tag:blogger.com,1999:blog-72558199128582463212024-02-20T02:58:29.640-08:00Schmivits for your amusementIhab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.comBlogger22125tag:blogger.com,1999:blog-7255819912858246321.post-30908081735534458902011-02-13T20:37:00.001-08:002011-02-13T20:58:12.750-08:00Valentine's Day Velomobile<meta charset="utf-8">For Valentine's Day, I made a cardboard model of a side by side tandem velomobile. The scale is 2 inches = 1 foot, and the wheels are 20" (406 or 451). As with my previous model, the goal is to come up with a reasonably streamlined shape that can be built out of flat panels and simple curves. Here are some pictures.<div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5l3mPXDMEOXhMC0fCwCALIg2aAh3sXcXrpEiOCVP_z0EltS3SORT6xkYDVHQCz9B4rwh0A7892KJexzes02OzzwYKiIL_QRBO5OBkjeOEpkD3RhfJjeR3asN5-UgQHdhA-5j9J0YscdE/s1600/IMG_2227.JPG"></a><div style="text-align: center;">
<br /></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_3gblzXGpaJCH2zApLt-cdahCX71Oc1GNcpHl_VSM69Aj8yUkxrEz4AieDu-6Vg7bT-mg1x6I2kWVyLCJ49ktP0zqnDpv0Td_CRSFMjcP0DwzzMOWZcFQf9b7xJz4KR-92hybIj3k-Q0/s1600/IMG_2224.JPG"></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgi1PkDHyDiNFqGDx_hCZTG5qvgJEY2Jabi4DVGB2N5djyWa6sVGpKvMxcgiWo9gOaFnX8-HVVIuncTm2sedzmRJk2a53gILRkGq8oTI5nARmcReLqOePM0FGeEQYj4CaE8TKAgkAqWywM/s1600/IMG_2235.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgi1PkDHyDiNFqGDx_hCZTG5qvgJEY2Jabi4DVGB2N5djyWa6sVGpKvMxcgiWo9gOaFnX8-HVVIuncTm2sedzmRJk2a53gILRkGq8oTI5nARmcReLqOePM0FGeEQYj4CaE8TKAgkAqWywM/s400/IMG_2235.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5573400235034270418" /></a>
<br /><div><meta charset="utf-8"><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_3gblzXGpaJCH2zApLt-cdahCX71Oc1GNcpHl_VSM69Aj8yUkxrEz4AieDu-6Vg7bT-mg1x6I2kWVyLCJ49ktP0zqnDpv0Td_CRSFMjcP0DwzzMOWZcFQf9b7xJz4KR-92hybIj3k-Q0/s400/IMG_2224.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5573400367103496722" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></span></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; ">
<br /></span></span></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><meta charset="utf-8"><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; "><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5l3mPXDMEOXhMC0fCwCALIg2aAh3sXcXrpEiOCVP_z0EltS3SORT6xkYDVHQCz9B4rwh0A7892KJexzes02OzzwYKiIL_QRBO5OBkjeOEpkD3RhfJjeR3asN5-UgQHdhA-5j9J0YscdE/s400/IMG_2227.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5573400576059001346" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></span></span></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; "><meta charset="utf-8"><span class="Apple-style-span" style="color: rgb(0, 0, 0); "><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiP0V4yQDg78jljY20V6F55FQYvtkMb7EgfpQygHPqI3a48GgzwLgCK2658tdSwnQrUgaB3PaC7xYgihfoJqW8EUHN1MdbyQ9S3iAnYKuLljIAqTv_rrCbadDBBVZpWAqr5b7Iq4Q7RSxE/s1600/IMG_2231.JPG"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiP0V4yQDg78jljY20V6F55FQYvtkMb7EgfpQygHPqI3a48GgzwLgCK2658tdSwnQrUgaB3PaC7xYgihfoJqW8EUHN1MdbyQ9S3iAnYKuLljIAqTv_rrCbadDBBVZpWAqr5b7Iq4Q7RSxE/s400/IMG_2231.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5573400676807222530" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></a></span></span></span></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; ">
<br /></span></span></div><div><meta charset="utf-8"><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdyDSO5REbg7SwHeCbNJ6w0ty9AWonc5gRE6rmVttIkgPHI-4kX49lyP_yqL4xuSYv2tquLkjetBzWSGDenlPR3KjE2dZwD20w3FutNUcYRnxFcLzLzxJxFa_yPKmYDFUukVTR98E6BNY/s400/IMG_2232.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5573400778242794322" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></span></div></div>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com1tag:blogger.com,1999:blog-7255819912858246321.post-14996974353462833522011-01-22T21:14:00.000-08:002011-01-23T08:45:51.905-08:00Velomobile concept<div style="text-align: left;">Today, I made a quick structural mockup for a velomobile. This design could be built in plywood; carbon fiber sandwich panels; or any of a number of other techniques -- but it's mostly designed to be built using conventional aircraft sheetmetal techniques. Among the design influences are:</div><div><ul><li><a href="http://www.alleweder.eu/">Alleweder</a></li><li><a href="http://www.recumbent-gallery.eu/completely-different-velomobile/">Velayo</a></li><li><a href="http://www.deferredprocrastination.co.uk/blog/2010/what-does-an-atomic-duck-look-like/">Atomic Duck</a></li><li><a href="http://sonexaircraft.com/">Sonex</a></li><li><a href="http://www.thatchercx4.com/">Thatcher CX4</a></li><li><a href="http://www.teenietwo.com/">Teenie Two</a></li></ul><div>I built the mockup out of cardboard and a glue gun, around an artist's poseable mannequin. The mockup is scaled to a 6 foot tall person so, given that the mannequin is exactly 12" tall, the scale is 2" to the foot:</div></div><div>
<br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDu_w4vVd5ZID2wvQ7rl4QbLS6efyGVkHGZEDul5KowPJhUZPB_UMMA1Gh4rowTSpXCwpU1C86DsNzOWRBB3lSht8UTazYnaB-kKUTd0XFnfQdXjP4056ezL2R9fehnK8LA0bCb8rdY_c/s400/IMG_2144.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5565248075727657794" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 300px; height: 400px; " /></span></div><div><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; ">This mannequin was from a garage sale, and apparently, some kids had their way with him. He is now the evil brains-eating velomobilist of death from hell. His new ride looks like this:</span></div><div><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; "><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkqpNTVoN3eaNkgR17GhAun4jI39mXTJKMReNXQZ2KltkRKPntPJ2ADFKC_Z_KeYpVSyxzUPNy45wL8JYh0FoByVpNW173IiGrE59QlYReAGSwAzlPJR3kC_ticaHUptGp4SbjPsTm0rw/s1600/IMG_2156.JPG"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkqpNTVoN3eaNkgR17GhAun4jI39mXTJKMReNXQZ2KltkRKPntPJ2ADFKC_Z_KeYpVSyxzUPNy45wL8JYh0FoByVpNW173IiGrE59QlYReAGSwAzlPJR3kC_ticaHUptGp4SbjPsTm0rw/s400/IMG_2156.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5565423334056745042" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></a></span></div><div><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; "><meta charset="utf-8"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4MHC_WXdj6rEm4-tM8x0yZ6OY7RUoEDPg_9776Z10ILkKkt6tGjCHWmpnuBBJ-bLuBunhqxY8NtfNMUgMmMNuawkv40ShmhY1GjOqOMxgkPMX_qy4Lk3JJLzISq_WPlSAbwcKeoCvuio/s1600/IMG_2146.JPG"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4MHC_WXdj6rEm4-tM8x0yZ6OY7RUoEDPg_9776Z10ILkKkt6tGjCHWmpnuBBJ-bLuBunhqxY8NtfNMUgMmMNuawkv40ShmhY1GjOqOMxgkPMX_qy4Lk3JJLzISq_WPlSAbwcKeoCvuio/s400/IMG_2146.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5565248527355642690" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></a><meta charset="utf-8"><span class="Apple-style-span" style="color: rgb(0, 0, 238); -webkit-text-decorations-in-effect: underline; "><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqH0MvLthNrK3iTigYxtdxfjNyOkkb_6NEp1hXrQOZGB3ITgIpV80A9CeksU3bgecAak24mv92eNatft9ZgnmVkV9ugblWFfLfWxx3Yl4d4IjNp5eEycrTFhT2gqu8MXBFfGFW-tfesQQ/s400/IMG_2151.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5565248906458804594" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></span></span></div><div>The body is intended to have three main bulkheads, as follows:</div><div><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHYc-6D76r9mJYlcp2Tplao0qryKEo-jzP9lwgm9jxDKdCzEfJ1feA_7vj1e2BgadTFNSJysrgKJtHKM_27K5RmSSG7GKZpj0q5wTPq38PVdzcoIvNAxi1sx9IhPJw5IXevL3qykKRY28/s1600/bulkheads.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHYc-6D76r9mJYlcp2Tplao0qryKEo-jzP9lwgm9jxDKdCzEfJ1feA_7vj1e2BgadTFNSJysrgKJtHKM_27K5RmSSG7GKZpj0q5wTPq38PVdzcoIvNAxi1sx9IhPJw5IXevL3qykKRY28/s400/bulkheads.png" border="0" alt="" id="BLOGGER_PHOTO_ID_5565415452568859442" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 303px; " /></a></div><div>The cockpit, i.e., the area between B and C, has curved sides; everything else is straight. The body is spanned by four longerons at the corners, perhaps made from aluminum angle:</div><div><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoMEKXGvaIsPQLjvkoY8YuumlQraqiKI8rSxKlq95xf_JjAryXcu8qRJQ6CETiFRbxR6QiU_V3pne1O9oV94ZFCEOxajgTNz3ScdhJXdQ4M7FXkxmmq4YCDv_urJfU_8xsBTvI06FSBw4/s1600/longerons.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoMEKXGvaIsPQLjvkoY8YuumlQraqiKI8rSxKlq95xf_JjAryXcu8qRJQ6CETiFRbxR6QiU_V3pne1O9oV94ZFCEOxajgTNz3ScdhJXdQ4M7FXkxmmq4YCDv_urJfU_8xsBTvI06FSBw4/s400/longerons.png" border="0" alt="" id="BLOGGER_PHOTO_ID_5565415555772499202" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 303px; " /></a>The lower longeron is gently curved in the cockpit area; the upper one is made of two straight sections and one curved one, joined similarly to the <a href="http://www.sonex604.com/images/aft_box/SplicePlate.jpg">Sonex splice plate</a>. Both longeron curves are only in one plane, making them easy to bend.</div><div>
<br /></div><div>Since the area between bulkheads B and C is open, we add two "tunnels" to reinforce it in torsion. (In my model, bulkhead B is not quite shaped like it should be.)</div><div><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2BsxkYSXkoyT0ddk5rFA7I4IAPvfQdREbDl6n2-uSOrUViXrFNI5iXiRxgo7-pRxJH48NM882ohMtJ38IcUjQCVtQJCBU_e-AAzSEB9xFoVD6mbo0YU7M9W8557aKTaVKY1i4Qa1Ka7c/s1600/torsionTunnels.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2BsxkYSXkoyT0ddk5rFA7I4IAPvfQdREbDl6n2-uSOrUViXrFNI5iXiRxgo7-pRxJH48NM882ohMtJ38IcUjQCVtQJCBU_e-AAzSEB9xFoVD6mbo0YU7M9W8557aKTaVKY1i4Qa1Ka7c/s400/torsionTunnels.png" border="0" alt="" id="BLOGGER_PHOTO_ID_5565415331812980642" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 303px; " /></a></div><div>The seat can either be a sling, between bulkheads B and C, or a solid structure of some sort. Here is a view with the rider in place:</div><div>
<br /></div><div><meta charset="utf-8"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW5w9Oj8V06f1uLcJF36pSd10e6we2PvYpcCpNKw2hA0DL1_xdGUca5cksYIR_K1NL0WWwqBmMS_ce-nqQ35Nh62jddQn78AJckLV6wzIf30_ovPD-XElrp8flcY30Cm7GxNg1WaqrKTg/s1600/IMG_2153.JPG"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW5w9Oj8V06f1uLcJF36pSd10e6we2PvYpcCpNKw2hA0DL1_xdGUca5cksYIR_K1NL0WWwqBmMS_ce-nqQ35Nh62jddQn78AJckLV6wzIf30_ovPD-XElrp8flcY30Cm7GxNg1WaqrKTg/s400/IMG_2153.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5565418027929490834" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></a>The front wheel structure (with or without suspension, as the case may be) is built into bulkhead A, and covered with a fiberglass fairing. Here it is with the fairing off:</div><div>
<br /></div><div><meta charset="utf-8"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgY3tIpKUg-8AeiEjioEF0d-LbnDjDgLKLbmF5sWqywHR-PW-LvcVCJyLYSlIZfzGOwWlURZ99u419Zr3OxGbSfrMHoQ-M7QWEYmDeRHpUkkjO4D177R7CYTbGRm-V8y27mFR76zTSmG0k/s1600/IMG_2150.JPG"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgY3tIpKUg-8AeiEjioEF0d-LbnDjDgLKLbmF5sWqywHR-PW-LvcVCJyLYSlIZfzGOwWlURZ99u419Zr3OxGbSfrMHoQ-M7QWEYmDeRHpUkkjO4D177R7CYTbGRm-V8y27mFR76zTSmG0k/s400/IMG_2150.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5565418417568000754" style="display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; text-align: center; cursor: pointer; width: 400px; height: 300px; " /></a>The rear wheel suspension is not clearly defined at the moment. Perhaps a swingarm attached to bulkhead C, similarly to the Alleweder? Or some further structure aft of bulkhead C? I don't know yet.</div>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com1tag:blogger.com,1999:blog-7255819912858246321.post-60811446221693925512010-02-15T16:04:00.001-08:002010-02-15T16:05:45.866-08:00A380 wing skinsThe secret of the A380 wings is finally revealed. Check out <a href="http://www.cadinfo.net/aerospace/building-the-worlds-largest-passenger-aircraft-wings/page-3">this article</a>. Apparently, each skin panel is prestressed in a custom jig and autoclaved. When it comes out, <span style="font-style:italic;">sproing!</span>, it's the right shape. Nifty, eh?Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-74054647228457660162010-02-14T14:13:00.000-08:002010-02-14T15:38:49.314-08:00My first A380 flightI recently went on a business trip to Sydney. On the outbound, I chose to go directly from KSFO to YSSY to save time. On the return, I went through KLAX specifically because the YSSY-KLAX leg was on an A380. This is my report of the journey on <a href="http://flightaware.com/live/flight/QFA11/history/20100213/0420Z/YSSY/KLAX">Qantas flight 11</a>.<br /><br />At YSSY, I couldn't see too much of the aircraft because of the sheer volume of the three jetways leading up to it.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMr9R99iIy2eT3ca-2LZ-dqWIgsaFeGIYoP32sbthuMBSHYXwx9QPBdBfO70lS_4C4j0x5Ct061LV1zALaM2YPVsbgSkYlFIQwOp9f4qnf9CiOv0zd17m7R6UPzd2xk-48wEfAT_fCIQQ/s1600-h/IMG_9290.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMr9R99iIy2eT3ca-2LZ-dqWIgsaFeGIYoP32sbthuMBSHYXwx9QPBdBfO70lS_4C4j0x5Ct061LV1zALaM2YPVsbgSkYlFIQwOp9f4qnf9CiOv0zd17m7R6UPzd2xk-48wEfAT_fCIQQ/s400/IMG_9290.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5438227316814124194" /></a><br />No matters, though. Welcome aboard!<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPAqnLFu23N_qd2k_OXzQtWnY3E1tOxKotWrnArXUhsnPPjf5__qy2uGbMnvCnEGOobPvNlD9CWDZtUz-VrV2wY4jwd_nA0z8sMLUyBAw4Pa0x6pFSSAEvOKUx1GmNwflVAQ0wexS4Y8I/s1600-h/IMG_9293.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPAqnLFu23N_qd2k_OXzQtWnY3E1tOxKotWrnArXUhsnPPjf5__qy2uGbMnvCnEGOobPvNlD9CWDZtUz-VrV2wY4jwd_nA0z8sMLUyBAw4Pa0x6pFSSAEvOKUx1GmNwflVAQ0wexS4Y8I/s400/IMG_9293.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5438226891424452690" /></a><br />Notice the nice bright new shiny anodized door latch hardware. It's the details that matter, you see. Once in, the economy class cabin is nice if not ostentatious:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEil7XAmcdv3ntG-k8X-ZZln5wnWmXSpvemoSBTvb36xIgGp6PrqdjXwKn5DRogzzM0HGzL5epQBLcUpfFMGMQy8_y6L0I51dVSEzBR1ImdgmmWmgGxK-Ct6RDZ9_TWhhCskjTJ3LhNeEnU/s1600-h/IMG_9299.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEil7XAmcdv3ntG-k8X-ZZln5wnWmXSpvemoSBTvb36xIgGp6PrqdjXwKn5DRogzzM0HGzL5epQBLcUpfFMGMQy8_y6L0I51dVSEzBR1ImdgmmWmgGxK-Ct6RDZ9_TWhhCskjTJ3LhNeEnU/s400/IMG_9299.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5438228113589249202" /></a><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcGSidBAfaLCdS-Nl_1Lb-jYTr4BZv9J3z4xl29Cvwljqg-idpVLurZNO-UnI0iA2HNpfIRD8QhruD2nSVbhnwDoBKWByyKS3cpT0oTITvW_BNB-F7Sh9rXfz-jijA0QUhbq36ZrpRT8E/s1600-h/IMG_9340.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcGSidBAfaLCdS-Nl_1Lb-jYTr4BZv9J3z4xl29Cvwljqg-idpVLurZNO-UnI0iA2HNpfIRD8QhruD2nSVbhnwDoBKWByyKS3cpT0oTITvW_BNB-F7Sh9rXfz-jijA0QUhbq36ZrpRT8E/s400/IMG_9340.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5438231521897957650" /></a><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh72afGc_l3xi70k6iSXTmIV3pL9dbbYXA6Dh23_yzChZCRljMIONbFx-mobDM2Vz7sDkyU-ree5QOezew2WLNLj05SP4RzITelFN5i4uRHfGGOQyTr8SNxwYJSZ_sm-bPeC58tG0O6wz0/s1600-h/IMG_9300.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh72afGc_l3xi70k6iSXTmIV3pL9dbbYXA6Dh23_yzChZCRljMIONbFx-mobDM2Vz7sDkyU-ree5QOezew2WLNLj05SP4RzITelFN5i4uRHfGGOQyTr8SNxwYJSZ_sm-bPeC58tG0O6wz0/s400/IMG_9300.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438232858095855010" /></a><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2V8Inz0hNU6diTKt9WdSFwzOBCihOCyy3YMC70da3DoeoQiU9ixuGEZNWXBDP0EV9qbD05NnrVIbpl8OIzHkgLNbRGXYq8ThyJ-rxeAK6OkhpqQY2zoYH4Nun0yFPLht53TaCpll_y60/s1600-h/IMG_9298.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2V8Inz0hNU6diTKt9WdSFwzOBCihOCyy3YMC70da3DoeoQiU9ixuGEZNWXBDP0EV9qbD05NnrVIbpl8OIzHkgLNbRGXYq8ThyJ-rxeAK6OkhpqQY2zoYH4Nun0yFPLht53TaCpll_y60/s400/IMG_9298.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438232683018262210" /></a><br />Notice that the plastic parts of the seats are carbon fiber. This is not just a "look": By moving back the edge of the upholstery, I could tell that the reverse side is also carbon, and the edges look black even though the resin is transparent. Most likely: they <i>are</i> real carbon. Nifty!<br /><br />The seats articulate such that, as the back is reclined, the seat pan moves foward. I would have loved to un-Velcro all the padding to show you how this clever design feature is made possible, but that might have gotten me into trouble, so I chose to demur. Instead, I'll point out that, apparently, the aircraft seatbelt latches of the future are automotive-style, not airplane-style:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtZb9yKA18VfQg7AQChNI9J4eB4CmIChw4Fz0q7Ec8AfrDJJLVMVSAP7R920drVtJeuFRKUib1_jUnEKPD_xfJRvNolEeKTmiaPJP-KoMl82w8OxfYhLk0QB83hGgDQHWHHBuMEMA5EqM/s1600-h/IMG_9301.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtZb9yKA18VfQg7AQChNI9J4eB4CmIChw4Fz0q7Ec8AfrDJJLVMVSAP7R920drVtJeuFRKUib1_jUnEKPD_xfJRvNolEeKTmiaPJP-KoMl82w8OxfYhLk0QB83hGgDQHWHHBuMEMA5EqM/s400/IMG_9301.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5438230017476591538" /></a><br />Behold the mighty wing that is to hold all this stuff up in the air:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIYt6gEBYsnq57JBiOeZiF6LSZzIhdAgSIEPGWwH1KtZNoKxUJD5cKTVwdcDIRrgDSO6F9X6uUsXB80njkggdpjKXF9_0_g7bDHit1blBi_7VBMJp7XXfwNP22NZAZC4WscJh5AbMbGqM/s1600-h/IMG_9302.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIYt6gEBYsnq57JBiOeZiF6LSZzIhdAgSIEPGWwH1KtZNoKxUJD5cKTVwdcDIRrgDSO6F9X6uUsXB80njkggdpjKXF9_0_g7bDHit1blBi_7VBMJp7XXfwNP22NZAZC4WscJh5AbMbGqM/s400/IMG_9302.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438234041881774130" /></a><br /><br />Now on to the star of our performance: The tail-mounted camera. This one thing is so useful, so <i>awesome</i>, that it makes me want to grab a <a href="http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=UNIBIT-21">step drill</a> and <a href="http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=J1451">Jilson snips</a> and add this to every commercial heavy on the planet. Here we are at the gate:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO3q2XoDQBzssChGksSruD2R8uUuepVFc2GpGG98eLQda5DIg_CPpDlouFPG4rNxZTsmbLAJ4dghKuDqPjjBiOaJt3-oIPmZugll9DBdoyii2Ge4Ed2h5Lnvpx4YNgPccmC7NEotWd150/s1600-h/IMG_9297.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO3q2XoDQBzssChGksSruD2R8uUuepVFc2GpGG98eLQda5DIg_CPpDlouFPG4rNxZTsmbLAJ4dghKuDqPjjBiOaJt3-oIPmZugll9DBdoyii2Ge4Ed2h5Lnvpx4YNgPccmC7NEotWd150/s400/IMG_9297.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5438231229417726530" /></a><br />Who wants an entertainment system that shows movies on demand when you have <i>that</i>, eh? Here we are ready for our takeoff roll:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyjFNb7z63jPWEJUvLNmwbeZeToUAiIIjmr45mPyBTj0RO0j0quKyBEOCLewYEmD7w8bq1DziD5mFNYa0yQJLl6HVygYEf7-2K5SZR5MSRtYtsARtpLGcZw5-SSehnVlv1KUWXpU4FO58/s1600-h/IMG_9316.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyjFNb7z63jPWEJUvLNmwbeZeToUAiIIjmr45mPyBTj0RO0j0quKyBEOCLewYEmD7w8bq1DziD5mFNYa0yQJLl6HVygYEf7-2K5SZR5MSRtYtsARtpLGcZw5-SSehnVlv1KUWXpU4FO58/s400/IMG_9316.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438233151812038258" /></a><br />And on climbout, with nifty vortices and Sydney harbor in the background:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEig6dJJ2dHDyfhRfH8fgcxVaHZQ8bvk-xJjAmPQfCcWc2mD89drLIfXqCKOxUahj78mqC4LOfmceg2WZm79O9tpYwFAFU_Xd1eBsusufa6HrDSIon4wPWMpV6rx0grqQGS2l6LRxdBSXco/s1600-h/IMG_9323.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEig6dJJ2dHDyfhRfH8fgcxVaHZQ8bvk-xJjAmPQfCcWc2mD89drLIfXqCKOxUahj78mqC4LOfmceg2WZm79O9tpYwFAFU_Xd1eBsusufa6HrDSIon4wPWMpV6rx0grqQGS2l6LRxdBSXco/s400/IMG_9323.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438233649049945506" /></a><br />Speaking of which, let's look at that wing in flight one more time:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgao7wQNFtB9FBiAo4KXC-NFuCE822SC7Ej1ws113YKTbKWNOs2wxmV63qGMS4Ev4ojcO_3SmwR2yLfOjD1elcLDlnlxwSEH4owDJbvd-h2jGovxZbWtRSNnVEzAgPYQWJaMKmMuqdoZng/s1600-h/IMG_9331.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgao7wQNFtB9FBiAo4KXC-NFuCE822SC7Ej1ws113YKTbKWNOs2wxmV63qGMS4Ev4ojcO_3SmwR2yLfOjD1elcLDlnlxwSEH4owDJbvd-h2jGovxZbWtRSNnVEzAgPYQWJaMKmMuqdoZng/s400/IMG_9331.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438234368335622738" /></a><br />Notice anything? Yes, compared to the ground photo, you can <i>see</i> the wing outboard of the #4 engine pylon. Curved downwards on the ground, the wing <i>straightens</i> in flight.<br /><br />Ok, here's a quick weekend project. Design a reliable, strong and lightweight mounting, articulation and actuation system for the wing control surfaces. This must take into account the flexure of the wing, and specifically, should maintain proper slot geometry for flaps and slats all along their length at all aerodynamically significant conditions. Remember that, if your mounting is off the neutral axis of the wing, the spanwise distance between your mounting points will change as the wing flexes.<br /><br />(Yes, I know this is a previously solved problem: all large aircraft must be designed with wing flexure into account. But, in this case, it's particularly dramatic.)<br /><br />Another weekend project: Design a wing that is curved downwards when unstressed. Now manufacture it. Notice that, strictly speaking, your unstressed top and bottom skins are actually double-curved.<br /><br />And now on to the <i>only</i> way to go flying, as ordered by Doctor Awesome:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKalglU6JrWgUC98mkJEFwQsSfLnXEhQ8nFyWoi0S4a2jOyUzrcK4HlgoeE5zEHfNBex_qJ1H6GhLJnSy04gC0loNmZfBXoZgW95Mp7ly5iFTGqCrmaqLxnAkfHPYwFMtm-8Oq_5f_s4Y/s1600-h/IMG_9341.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKalglU6JrWgUC98mkJEFwQsSfLnXEhQ8nFyWoi0S4a2jOyUzrcK4HlgoeE5zEHfNBex_qJ1H6GhLJnSy04gC0loNmZfBXoZgW95Mp7ly5iFTGqCrmaqLxnAkfHPYwFMtm-8Oq_5f_s4Y/s400/IMG_9341.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438236132751412930" /></a><br />This is me programming, while keeping tabs on our status. :) Unfortunately, there is one source of silliness: the "warning" on the display. This comes up, and makes the rest of the screen "grayed out", whenever there is a PA announcement. How annoying. Hrmph. Incidentally, the power connector is on the back of the armrest of the seat in front of you (it took me a while to find it):<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeaxX-qqym4QoIrzGyRqmTwiarvO11c2em6gM4s421hUggjOVXyDf80AwFVp_S9nypowMv3cRRsBtrlB532xdHTbC3UuSe1EJqUItPVfjGGxwECJjsjFofYDvwwm29Ii2P5DIq6luLB8Q/s1600-h/IMG_9305.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeaxX-qqym4QoIrzGyRqmTwiarvO11c2em6gM4s421hUggjOVXyDf80AwFVp_S9nypowMv3cRRsBtrlB532xdHTbC3UuSe1EJqUItPVfjGGxwECJjsjFofYDvwwm29Ii2P5DIq6luLB8Q/s400/IMG_9305.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438237011847857810" /></a><br />There are RJ-45 and USB sockets on the end of your own armrest, but on my flight, these did not provide any useful connectivity (though perhaps the USB was powered).<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDBlaYsCNa1Zl4eHN3VaoVGupzdf2-bZCch3VOT0hQDJveYwabXgvP-Z_1Jy8i1i2HQx3_Oip9E7zeZLwr0Qa9CimaID-PBlJd7w2NJBd0f7D_hoIjARl7d2MX_gknvoKLGJV-6UtWi3U/s1600-h/IMG_9295.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDBlaYsCNa1Zl4eHN3VaoVGupzdf2-bZCch3VOT0hQDJveYwabXgvP-Z_1Jy8i1i2HQx3_Oip9E7zeZLwr0Qa9CimaID-PBlJd7w2NJBd0f7D_hoIjARl7d2MX_gknvoKLGJV-6UtWi3U/s400/IMG_9295.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438237417110135554" /></a><br />One of the "problems" with this ship is that it is noticeably quieter than the average commercial heavy. Why is that a problem? Because the all-night chit-chat of the flight crew in the nearby kitchen was audible enough to keep me up! D'owww! :) It did not help that I was consuming uppers and downers together:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO_ns-JHGPOHiwOgnKn_lgU1kr0PDdKCiNLif1PhNkyzcjnvrTFYim4D9yse8_lskzWze1zS-OKQRyARA-cpPvhMjD4EJI_OScTL4XBvamuI_o0xpwTFkL-Ht1TN5L6mlM7SmMChORprc/s1600-h/IMG_9346.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 480px; height: 360px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO_ns-JHGPOHiwOgnKn_lgU1kr0PDdKCiNLif1PhNkyzcjnvrTFYim4D9yse8_lskzWze1zS-OKQRyARA-cpPvhMjD4EJI_OScTL4XBvamuI_o0xpwTFkL-Ht1TN5L6mlM7SmMChORprc/s400/IMG_9346.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438243937107950722" /></a><br />Obligatory potty shot: The faucet is temperature adjustable and activated by a proximity sensor, like all decent bathrooms worldwide. Why it took so long for aircraft to adopt this "new" idea is totally beyond me.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTACFO3fUv1pRHBq-x7Aa4v_PeqUykeR-uCPYWmwlmlW-ZVHdCozlzbOJbkgzG3x8HBzhXdt8xyQ_Fcm973HyO0biEHFsRyJL353yMuc3NqqdCNM1M6o_MRrJuMtIy44hB0ndxxzDmM0c/s1600-h/IMG_9358.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 480px; height: 360px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTACFO3fUv1pRHBq-x7Aa4v_PeqUykeR-uCPYWmwlmlW-ZVHdCozlzbOJbkgzG3x8HBzhXdt8xyQ_Fcm973HyO0biEHFsRyJL353yMuc3NqqdCNM1M6o_MRrJuMtIy44hB0ndxxzDmM0c/s400/IMG_9358.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438244642083423762" /></a><br />Finally, we arrived, a little bleary-eyed but none the worse for wear. Here is an awesome, if blurry, shot of us approaching the California coastline with spoilers deployed:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeYgauMV7nPnU3G0ShtsaRfvce6y5GWrLdoQaunOTFDbv3xRr0I4woOWff-2erREa6uqkbGOBGkxtBHvOxWUmeMIlZ6DFSgIZNTKwVoeyZO8yh8lCUhjLQXiJrjDKWXtiXZhGjiZzU3TY/s1600-h/IMG_9368.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeYgauMV7nPnU3G0ShtsaRfvce6y5GWrLdoQaunOTFDbv3xRr0I4woOWff-2erREa6uqkbGOBGkxtBHvOxWUmeMIlZ6DFSgIZNTKwVoeyZO8yh8lCUhjLQXiJrjDKWXtiXZhGjiZzU3TY/s400/IMG_9368.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438237740381626674" /></a><br />Flying what looked like a downwind for KLAX 24R:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJCJ9KJJOs_-fa7DmIztKGt84lpZ5Ke8GYQXeYBU1JANFuA8tBLhQmfoE7nliS_Ch5t7Y-usUAXy1J1D2OK0vFXviodTUOCVWpCqxTxB_ygpL5uqtHfIeu8-8KODikz34nK-tV13fMnkc/s1600-h/IMG_9370.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJCJ9KJJOs_-fa7DmIztKGt84lpZ5Ke8GYQXeYBU1JANFuA8tBLhQmfoE7nliS_Ch5t7Y-usUAXy1J1D2OK0vFXviodTUOCVWpCqxTxB_ygpL5uqtHfIeu8-8KODikz34nK-tV13fMnkc/s400/IMG_9370.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438238031879463330" /></a><br />Turning final, likely over <a href="http://www.airnav.com/airspace/fix/PALAC">PALAC</a>, with downtown LA in the distance: <br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkHgVFfkvEPfzL6TmmDSJ-kJUc_yyAd-GTVj0HnpaIZ5_8au_fyPw48FZP7OXq0Hu67h8Wju0O4f8ES8hbXf_McfFkpZnuyVlWX1GXQlIc4cVttxpTgacnjQDAcwq21_6ZPJ6ONwxGbs8/s1600-h/IMG_9375.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkHgVFfkvEPfzL6TmmDSJ-kJUc_yyAd-GTVj0HnpaIZ5_8au_fyPw48FZP7OXq0Hu67h8Wju0O4f8ES8hbXf_McfFkpZnuyVlWX1GXQlIc4cVttxpTgacnjQDAcwq21_6ZPJ6ONwxGbs8/s400/IMG_9375.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438242017359581890" /></a><br />And braking on the ground:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYbY3jDc6yNfAOHrD5a17X6Rl-kItUFhpk-MzV6qmSSgXI7x8nQxA8c4JlgbmyKpWPQ-a4PqKoYf4JTwldOGJBu-sgUpcAtNpBroURYrjXZDb6CD5cwe_Wc5ncd5lb6U0H8EPd53RYxJg/s1600-h/IMG_9381.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYbY3jDc6yNfAOHrD5a17X6Rl-kItUFhpk-MzV6qmSSgXI7x8nQxA8c4JlgbmyKpWPQ-a4PqKoYf4JTwldOGJBu-sgUpcAtNpBroURYrjXZDb6CD5cwe_Wc5ncd5lb6U0H8EPd53RYxJg/s400/IMG_9381.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438242327338921410" /></a><br />Finally, it's time to say goodbye to my ride:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEju8uVvI3MAxOEvYDMUiZrZ5EKkALTFTF6Nm-ZIqSXhlwVYj_yZO38dZwSVmnThIWaDbA6FskiDhtqHtXhTm5fO7XcK7tuTHfPGu1ePL2QUjT7O9ViM9pUqsYwLWuhmYb8VPA1l2CfaDGs/s1600-h/IMG_9387.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEju8uVvI3MAxOEvYDMUiZrZ5EKkALTFTF6Nm-ZIqSXhlwVYj_yZO38dZwSVmnThIWaDbA6FskiDhtqHtXhTm5fO7XcK7tuTHfPGu1ePL2QUjT7O9ViM9pUqsYwLWuhmYb8VPA1l2CfaDGs/s400/IMG_9387.JPG" border="0" alt=""id="BLOGGER_PHOTO_ID_5438242501920993618" /></a>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-77923007339932213382009-06-01T20:47:00.000-07:002009-06-01T20:49:23.126-07:00Another riveted recumbentCheck out <a href="http://rivetrecumbentbike.com/">The Commuter Riveted Aluminum Recumbent Bicycle Plans</a>. Cool!Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-68289894330859403492009-05-25T13:39:00.000-07:002009-05-25T13:57:04.018-07:00Another little airplaneOn Saturday, May 21, we drove to <a href="http://www.airnav.com/airport/L36">Rio Linda Airport</a> for the 6th Annual Northern California <a href="http://www.sonexaircraft.com/">Sonex</a> Fly-in. Wow! The Sonex is one of the most amazing light aircraft designs out there. The airframe is filled with cute little tricks that make the construction simple yet strong. The design has an excellent track record and many dedicated followers. One aircraft that taxied in was powered by a <a href="http://www.usjabiru.com/3300.html">Jabiru 3300</a> engine. For reference, for those who haven't been there: it sounded no louder than a lawn mower; clearly, this is a very refined and well-muffled engine.<br /><br />Unsurprisingly, today, my son Aden (6yo) wanted a Sonex of his own. I copied the 3-view from the Sonex website into my CAD program and made some very simple cutting diagrams. We then cut stencils out of paper:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5kFcE6XGqN1DMFtlAnMIXKY4RhurkSsrC5b_DTHB4x0lIpTi7fPaU-1ft0kNjBulIeJIE1bsPjsyzYT9N8kFwIALYYrkdctH2IfYZzNpj1FdNSEPBOnem6bPVjRAlsYPKyvR_P0P_nZI/s1600-h/IMG_7585.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5kFcE6XGqN1DMFtlAnMIXKY4RhurkSsrC5b_DTHB4x0lIpTi7fPaU-1ft0kNjBulIeJIE1bsPjsyzYT9N8kFwIALYYrkdctH2IfYZzNpj1FdNSEPBOnem6bPVjRAlsYPKyvR_P0P_nZI/s400/IMG_7585.JPG" alt="" id="BLOGGER_PHOTO_ID_5339866373974860562" border="0" /></a><br />We cut the parts out of balsa:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9Uqhxx7BXW6CBidMBjSGgyEz_uUOoDp6DeZwbaBr72euKBBaQ5f0jmFTxBsU-qKtvpWu6RNZQT98WYC2gdsyTIFTeGy1k3j3dVrd7wV540NcJxRIADdVcTqSZJXKWvvGbnBJWfd_gYG4/s1600-h/IMG_7591.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9Uqhxx7BXW6CBidMBjSGgyEz_uUOoDp6DeZwbaBr72euKBBaQ5f0jmFTxBsU-qKtvpWu6RNZQT98WYC2gdsyTIFTeGy1k3j3dVrd7wV540NcJxRIADdVcTqSZJXKWvvGbnBJWfd_gYG4/s400/IMG_7591.JPG" alt="" id="BLOGGER_PHOTO_ID_5339866900161035522" border="0" /></a><br />We then attached everything with a glue gun:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEji1rxeYMmcg9HJsln64Nm_heTz5PNnzb8vmxg0gwRJ7LnobFODISiDzseeisY3KoeITRJYRFyexdUD2pY2LzWIm3-brnCJt0NMwPKzMt289eKzAJVeHTk-33_0wCEioUDRHiwkns_zbvw/s1600-h/IMG_7593.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEji1rxeYMmcg9HJsln64Nm_heTz5PNnzb8vmxg0gwRJ7LnobFODISiDzseeisY3KoeITRJYRFyexdUD2pY2LzWIm3-brnCJt0NMwPKzMt289eKzAJVeHTk-33_0wCEioUDRHiwkns_zbvw/s400/IMG_7593.JPG" alt="" id="BLOGGER_PHOTO_ID_5339867065625618146" border="0" /></a><br />I then made him a quick and dirty nose with scrap balsa. The result is a happy little Sonex fan:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAzAuUU7n1niG1Jh-WtFyh3lJEMEIRqW13fLSmR5EH2WvCa9spPGqyHoBRVUDOJQ67-GAmqicCr7PxtlEdCNeqR5vrEFoX4y-HMtFqd9Z5gPAcTQgJw0gPtQ7S3Lp9lXaIq5Yh4-5fhSI/s1600-h/IMG_7595.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAzAuUU7n1niG1Jh-WtFyh3lJEMEIRqW13fLSmR5EH2WvCa9spPGqyHoBRVUDOJQ67-GAmqicCr7PxtlEdCNeqR5vrEFoX4y-HMtFqd9Z5gPAcTQgJw0gPtQ7S3Lp9lXaIq5Yh4-5fhSI/s400/IMG_7595.JPG" alt="" id="BLOGGER_PHOTO_ID_5339867428024217186" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK6pO7_0V_AhQRFztHpiviOXxe3zvHfgigXkgGozB_winZCeI0nLfWtBGa0wLCkLbLLGOdbngpatqk1tRLXRwN5YLI6iiD2osQKXupwWTf6zP3PSangLInEI8w9cI5wlm3OTrCGOrsC_Q/s1600-h/IMG_7596.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK6pO7_0V_AhQRFztHpiviOXxe3zvHfgigXkgGozB_winZCeI0nLfWtBGa0wLCkLbLLGOdbngpatqk1tRLXRwN5YLI6iiD2osQKXupwWTf6zP3PSangLInEI8w9cI5wlm3OTrCGOrsC_Q/s400/IMG_7596.JPG" alt="" id="BLOGGER_PHOTO_ID_5339867499766184658" border="0" /></a>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-47507816367682390462009-01-04T19:18:00.000-08:002009-01-04T19:28:04.733-08:00Trim blues<div>I suspect I might be genetically unable to trim model gliders.</div><div><br /></div><div>I tried and tried with the little homebrew FF glider (see previous post). I moved the CG forward then experimented with all possible variations of wing and tail incidences. I was not able to get two consecutive consistent flights: with what seemed like the exact same settings, one flight would be lovely, floating down to a nice pretty flare, and the next twenty would either climb and stall, or dive.</div><div><br /></div><div>Perhaps it's my launching method. I mean, I can't really say I was consistent in my (hand) launches, and the six feet from my hand to the ground does not give the glider lots of room to settle into a nice trimmed attitude and speed. But still.</div><div><br /></div><div>I suspect I should just buy some RTF (better than a Guillows toy, but not necessarily the fanciest) and follow the instructions (especially about CG settings) religiously, hoping to build experience in how a properly constructed glider <span class="Apple-style-span" style="font-style: italic;">should</span> feel. Or maybe I should join the AMA and get someone to teach me. Or <span class="Apple-style-span" style="font-style: italic;">something</span>.</div>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-84086691179545435542009-01-03T20:28:00.000-08:002009-01-03T21:26:21.796-08:00Quick FF model gliderThis weekend, my son Aden and I made this quick free flight model glider:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLZuxsEzH8deiouZXuEP9BT6TQ8RgitVUwrpHNKf6OlGOTRtp8v7QCRqEujls7gnjcNSwZ3gW4m97m9YiTqnUyYSrxY9pAvaiMLrenqQTfj6B6ycK5DXaxEo8xdU2SUgdWsrs9oyBclgU/s1600-h/IMG_6630.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLZuxsEzH8deiouZXuEP9BT6TQ8RgitVUwrpHNKf6OlGOTRtp8v7QCRqEujls7gnjcNSwZ3gW4m97m9YiTqnUyYSrxY9pAvaiMLrenqQTfj6B6ycK5DXaxEo8xdU2SUgdWsrs9oyBclgU/s400/IMG_6630.JPG" alt="" id="BLOGGER_PHOTO_ID_5287304439194769474" border="0" /></a><br /><div><br /></div><div>We started with the <a href="http://secure.hobbyzone.com/catalog/HZ/hobbyzone_phantom/hobbyzone_phantom_parts/HBZ4720.html">wings</a> and <a href="http://secure.hobbyzone.com/catalog/HZ/hobbyzone_phantom/hobbyzone_phantom_parts/HBZ4731.html">tail</a> of a <a href="http://www.hobbyzone.com/">HobbyZone</a> <a href="http://www.hobbyzone.com/rc_planes_hobbyzone_firebird_phantom.htm">Firebird Phantom</a> park flyer. The fuselage is made of two strips of 1/8 x 1/2 balsa stick sheeted with 1/32 on either side. We didn't bother to draw a detailed design. First, we laid the top and bottom strips in the curved shape we wanted with some guide blocks on a building board, and added some cross pieces in between. Then we added one side sheet, removed from the board, trimmed the sheet, and cut and inserted a noseblock. Finally, we added the other side and trimmed, and sanded the corners.</div><div><br />(I learned this fuselage construction method from an issue of what must have been <span style="font-style: italic;">Radio Modeler</span> magazine back in the 1970s. And it's been <span style="font-style: italic;">years</span> since I've done any model airplane stuff. Let's see how far we get this time....)<br /><br /></div><div>When first test flown, the CG was too far back: it had little or no tendency to adjust its pitch attitude as a function of its speed, and would either dive and crash, or climb and stall. Part of the problem is that we used steel ball bearings, rather than lead shot, for the nose weight, and we ran out of space in the nose compartment.</div><div><br /></div><div>We are still testing. Stay tuned for more details.</div><div><br /></div><div>By the way: notice the price of the whole Firebird Phantom is only about $50, while the wings and tail alone cost a whopping $17.50. Whassapwiddat? If they can afford to sell the whole thing -- motor, RC, fuselage and everything -- for fifty bucks, then these two parts can't be costing them more than a buck each to make.</div><div><br /></div><div>So, note to self: next time, build up the tail surfaces from balsa and Monokote. The hinged elevators on the store-bought foam surfaces are a useless pain anyway, and the tail surfaces don't need to be cambered so they should be pretty easy to make.<br /></div>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-80376654556458484792008-10-26T13:27:00.001-07:002008-10-26T14:19:31.035-07:00B&M IQ Fly Senso Plus dissectionI've wanted a <a href="http://www.sheldonbrown.com/dynohubs.html">Sturmey Archer Dynohub</a> on my <a href="http://www.rcoc.co.uk/">Raleigh Chopper</a> since the mid 1970s. Now, I've finally decided to treat myself to a hub dynamo.<br /><br />After some research -- and much resistance of my lust for the multi-centibuck machined aluminum alternatives -- I bought a <a href="http://www.bumm.de/index-e.html?docu/174q-e.htm">B&M Lumotec IQ Fly Plus Senso</a> headlight. Here are a couple of exterior photos:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrZlL3ilPiiyGuR4XQWIQGBaYoRLPy3Jl11wuD106gVW9vrlEsOVdAFdG8XuTDDTPZ7qnxS1Rmj-52C41jH-IE7qBPGk-kpeXyrjltvYxlMHosrOL525DyVvN8KiDjbDk96bmdbg4aZpU/s1600-h/IMG_5796.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrZlL3ilPiiyGuR4XQWIQGBaYoRLPy3Jl11wuD106gVW9vrlEsOVdAFdG8XuTDDTPZ7qnxS1Rmj-52C41jH-IE7qBPGk-kpeXyrjltvYxlMHosrOL525DyVvN8KiDjbDk96bmdbg4aZpU/s400/IMG_5796.JPG" alt="" id="BLOGGER_PHOTO_ID_5261563881428429746" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHa6Jm3XhOAry-O-4PLVHaOeZ1lVoZsGXDLmucAFpV5aiMmBEtyT3ZNTw__gAGgNWEu0nR6PjLR6WDkq5q4X5gECMb6RXukzzeq9-PT4-ew31aJ2o5Dj_4S846Pm_4lvdhauosx33MGYA/s1600-h/IMG_5793.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHa6Jm3XhOAry-O-4PLVHaOeZ1lVoZsGXDLmucAFpV5aiMmBEtyT3ZNTw__gAGgNWEu0nR6PjLR6WDkq5q4X5gECMb6RXukzzeq9-PT4-ew31aJ2o5Dj_4S846Pm_4lvdhauosx33MGYA/s400/IMG_5793.JPG" alt="" id="BLOGGER_PHOTO_ID_5261568685669141906" border="0" /></a><br />In the rear view, note the white spot beside the switch: that is the opening for the light sensor. Note also the two pairs of spade terminals, and the built-in power wire. Here is one more shot showing how the emitter faces backward and downward against the reflector:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjiqsLDR7_SiIP5qPgsQZl5F17ho0-yHTVufRX9MfgtOnrgGxang5nw84sHVWRo_M47AjAg2e3kQk94JO-0aawIWeHmcCJBsIhsEUeZFuUbg5FcE6hVdpemNxj2sh16nUyX0GmuQFpVq10/s1600-h/IMG_5797.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjiqsLDR7_SiIP5qPgsQZl5F17ho0-yHTVufRX9MfgtOnrgGxang5nw84sHVWRo_M47AjAg2e3kQk94JO-0aawIWeHmcCJBsIhsEUeZFuUbg5FcE6hVdpemNxj2sh16nUyX0GmuQFpVq10/s400/IMG_5797.JPG" alt="" id="BLOGGER_PHOTO_ID_5261569967620824482" border="0" /></a><br />After some messing around, I decided that this must be the effective circuit for the thing:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuevRfn-aAHM_R3f4ps4z1paELQZp9gwQX9fNa4v96fqOScwHwyuzdfOfwOyafTW_vlhZhbfyX6v_e7kXlDVrT0adHlL722t2VcFhLHvOYhMLqMsns6EMTRPaXYRs8ES2JzXUKfNQPhHQ/s1600-h/iqFlyCircuit.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 196px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuevRfn-aAHM_R3f4ps4z1paELQZp9gwQX9fNa4v96fqOScwHwyuzdfOfwOyafTW_vlhZhbfyX6v_e7kXlDVrT0adHlL722t2VcFhLHvOYhMLqMsns6EMTRPaXYRs8ES2JzXUKfNQPhHQ/s400/iqFlyCircuit.png" alt="" id="BLOGGER_PHOTO_ID_5261569154648124482" border="0" /></a><br />Specifically: the switch is single-pole on the power side; the standlight capacitor does not appear to drain back into the spade terminals when the power is turned off; and the spade terminals bypass the switch.<br /><br />This last fact is highly annoying. It means that, to use a hub dynamo, you must use their supplied wire. Which happens to be too short to work with my recumbent bicycle. But the wire is built in and cannot easily be replaced -- either to make it longer or, as is likely down the line, to fix it if it starts to wear from road vibration.<br /><br />What I really wanted to do was to cut the provided cord short and attach connectors of some sort, then use these to attach my own wiring. But I was worried about what would happen if I messed up and needed to redo the connection. Should I cut the cord longer than I would like just in case? Even more annoying!<br /><br />It's usually easy to convince me to take something apart; this was the excuse I was waiting for.<br /><br />To open the thing, I pried off the front cap (which holds the reflector) with a flat screwdriver. This does mar the finish a bit and also slightly damages the clips that hold the cap in place, and will I'm sure Void Your Warranty™, so proceed at your own risk:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtRMAszng-2I1kc5k_VyIUsbOp7YyDVDgw7999lpuco0143tsDcqaRoyBs9wIHFsDwOU_YU0RJaZl9f23hUEsxoUIgAcnWpR_5ozZoUeKP85o3t9UemF4W37J50hWdBlmpTsMCcKkM68M/s1600-h/IMG_5799.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtRMAszng-2I1kc5k_VyIUsbOp7YyDVDgw7999lpuco0143tsDcqaRoyBs9wIHFsDwOU_YU0RJaZl9f23hUEsxoUIgAcnWpR_5ozZoUeKP85o3t9UemF4W37J50hWdBlmpTsMCcKkM68M/s400/IMG_5799.JPG" alt="" id="BLOGGER_PHOTO_ID_5261571571760322178" border="0" /></a><br />Here is a view of the opened unit looking at the circuit board from the front:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-EEOhCyaW_VcGQQSvtcWsthkmFLaV1vp5XRI3MQDf4gzviS_RvutVD0aw28Jx8Zy1otb8xLj6voBmF6JPmSXtae_DH1SvpG87sKpc_emkQ7GqYkC_Y9r92NdqhpKb_C0OhqtLbxv7fd0/s1600-h/IMG_5789.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-EEOhCyaW_VcGQQSvtcWsthkmFLaV1vp5XRI3MQDf4gzviS_RvutVD0aw28Jx8Zy1otb8xLj6voBmF6JPmSXtae_DH1SvpG87sKpc_emkQ7GqYkC_Y9r92NdqhpKb_C0OhqtLbxv7fd0/s400/IMG_5789.JPG" alt="" id="BLOGGER_PHOTO_ID_5261572278249567506" border="0" /></a><br />The circuit board is retained inside the back case by the two small screws in the picture. Note that B&M did not bother to put strain relief in the power cord. Tsk tsk. One fortunate fact, though, is that the points where the cord is soldered onto the circuit board are pretty easily accessible should the cord need to be replaced. Happiness. But while we're having fun taking things apart, why stop here...?<br /><br />This is the back of the circuit board, revealing the standlight capacitor:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8w4s3-hZ5Re1Wjg5WjfczIHwYUDnlkQcauM58df25HgvElyAgBueRBN6cfG20QTs8QlzD4bm9fwJNyTObxOO9YM6OTtJcqxfLZIE7O-tEHiydsDbBuGcHownOkUJB5H8ZaJfKu1rJ7Ds/s1600-h/IMG_5792.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8w4s3-hZ5Re1Wjg5WjfczIHwYUDnlkQcauM58df25HgvElyAgBueRBN6cfG20QTs8QlzD4bm9fwJNyTObxOO9YM6OTtJcqxfLZIE7O-tEHiydsDbBuGcHownOkUJB5H8ZaJfKu1rJ7Ds/s400/IMG_5792.JPG" alt="" id="BLOGGER_PHOTO_ID_5261573412687492578" border="0" /></a><br />As you can see, the light sensor on the board is the little square white dot to the left of the switch. Finally, here are two shots of the innards of the actual beam unit:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfvAA5OpaOia7xLrGCbNgiem9ufX5mH8pYGCZIboyN7D6Xg44-etAUZgbNkovKbgDHUDsWZrjzHtQGYS1Xtx4O_QtAdYgvas1yN3ZUuk4mbpyZU5CGo7PmKHGy5xUElehsJiJ1P2ZoMvo/s1600-h/IMG_5790.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfvAA5OpaOia7xLrGCbNgiem9ufX5mH8pYGCZIboyN7D6Xg44-etAUZgbNkovKbgDHUDsWZrjzHtQGYS1Xtx4O_QtAdYgvas1yN3ZUuk4mbpyZU5CGo7PmKHGy5xUElehsJiJ1P2ZoMvo/s400/IMG_5790.JPG" alt="" id="BLOGGER_PHOTO_ID_5261574196244638082" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzXnIgWhqxvcOp-5hX-8NF5CMPL_WaWIgVtSIFwOM8D8SEd0qgaFze7IBpjGEV3lHZMb1I0-w8gHR51QiA62f0cXJF-4Ml-ynWBiYWwfkS_PV6jEkWFD5MhLnsLdhuLqtcxARDFsLzM_I/s1600-h/IMG_5791.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzXnIgWhqxvcOp-5hX-8NF5CMPL_WaWIgVtSIFwOM8D8SEd0qgaFze7IBpjGEV3lHZMb1I0-w8gHR51QiA62f0cXJF-4Ml-ynWBiYWwfkS_PV6jEkWFD5MhLnsLdhuLqtcxARDFsLzM_I/s400/IMG_5791.JPG" alt="" id="BLOGGER_PHOTO_ID_5261574549223504658" border="0" /></a><br />In the second image, you can see the emitter; the formed aluminum heatsink; the reflector unit; and a retainer spring that holds the heatsink against the emitter when assembled. I expected thermal grease between emitter and heatsink, but there was none.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com3tag:blogger.com,1999:blog-7255819912858246321.post-30331177845442119402007-11-27T22:43:00.001-08:002007-11-29T20:43:49.284-08:00Simple bending brakeThis is a simple 2' bending brake I built recently. The goal is to validate the overall design approach in preparation for building a 4' version.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhca15cy6kIyGbDBeS2NGKYobx7hB5pqko6zLbwLlqiJnPu10bECcaWIooEj5KNKN2n4p7VsZbAebyiXLR70D937yiznuXT8F_-WVcNFNdL-cYBqiTs_S81mWPVR7pp3L4HFJcR08UnW-I/s1600-h/IMG_3497.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhca15cy6kIyGbDBeS2NGKYobx7hB5pqko6zLbwLlqiJnPu10bECcaWIooEj5KNKN2n4p7VsZbAebyiXLR70D937yiznuXT8F_-WVcNFNdL-cYBqiTs_S81mWPVR7pp3L4HFJcR08UnW-I/s400/IMG_3497.JPG" alt="" id="BLOGGER_PHOTO_ID_5137778613282553858" border="0" /></a><br />The leaf and bed are 1x4 oak from Home Depot. The bending bar is made of two pieces of 1x2 hard maple from a local lumberyard, topped with a piece of 1x4 pine, and a 1/8" radius is created with a <a href="http://www.amazon.com/Freud-80-122-Traditional-Beading-8-InchShank/dp/B00004T7K9">beading router bit</a>. The bed is screwed down to a large 2x6 for stability; the latter is clamped my workbench during use. (The reason the bending bar is in several pieces is because I didn't want to buy a wide -- read, expensive -- single piece of maple. I'll splurge for the next brake.)<br /><br />The construction is pretty obvious. I ensured proper alignment of the edges of the leaf and bed with the edge of the piano hinge by "match drilling" each side separately while fixtured to a base, like this:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOMCfG2i8OBbfUqcjYp-6zGOQuxtrc3kvEMSXCp7xcxMJKMIKm5eb2e-A6BEStqAZAhuP6I5YWaQn6XnuUtXOPikZWn13xE0h8pgXMG4Z4a1TDS0COM6CuSTQSJdSgWRjokyVfw4Buz9g/s1600-h/IMG_3041.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOMCfG2i8OBbfUqcjYp-6zGOQuxtrc3kvEMSXCp7xcxMJKMIKm5eb2e-A6BEStqAZAhuP6I5YWaQn6XnuUtXOPikZWn13xE0h8pgXMG4Z4a1TDS0COM6CuSTQSJdSgWRjokyVfw4Buz9g/s400/IMG_3041.JPG" alt="" id="BLOGGER_PHOTO_ID_5138422957161201762" border="0" /></a><br />For the <a href="http://www.sizes.com/tools/woodscrewpilot.htm">#8 wood screws</a> I used, I match drilled using an 11/64" drill for the unthreaded portion, ensuring reproducible alignment. I also drilled a deeper, pilot hole for the threaded portion. (Note that, in so doing, I ignored the pre-drilled holes in the hinge.)<br /><br />One problem I encountered -- perhaps because my pilot holes were too small, or not perfectly centered, or whatever -- is that the (admittedly, small and questionable quality) wood screws would torque off at the junction between the threaded and unthreaded portions.<br /><br />I added setback stops to provide a repeatable location for the bending bar:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZ7AvwjYGCNChUvNX9AcBeZEXq3w0JqnbqxO0REwEiRxnP6fwAVkVwZ5KDuqDGont7W7pE_m3oIibCLFg9vuoo-9x5gYKkmFxhZhSdZiB-4GCHA9zoECHly1m77aSibMG4fNQyUBiLtV8/s1600-r/IMG_3521.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFJQkxb29yz82GV1i7b5PryMtl1t1WJafZWw5OwZEVgjIx09ankP5Qc3DKWdaLqBP83DC9dLLLs9jm1yqgH-skzRH0aYwLwRxOc3-EqyPB320RY8fMTCljMGBtD59U2ZPhGU18blLKMto/s400/IMG_3521.JPG" alt="" id="BLOGGER_PHOTO_ID_5138485259956797602" border="0" /></a><br />I aligned the stops by putting some scrap into the brake, raising the leaf to the angle I expected I would need to get a 90 degree bend taking springback into account, then snugging the bending bar forward evenly:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyge_TUuQE8osVcyzJzMmgKbOmEpgGAEvHMgtApGQsCPEQOJPFHhfnd0FBIxylFqLRj4MBjcZmVkiBBD34GQAE7oKfRj4BriM3EA8c-BqBYbBCU6jylmeXoyW-Jfii1vmjf8OJGBhGMyI/s1600-r/IMG_3519.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkSFs4R1fZxleOzlSMIQTfMKe1UAH7nWbTRp0O5l_LYsUXuVb34OdWeoi22E1UnlVGoCCOGYdu00KGENnVcIhLzg2DVOMlh2fpkGVPphXv9ew0ooxvVfRZZZ1ucQbgu4IU5_BlT01-IdM/s400/IMG_3519.JPG" alt="" id="BLOGGER_PHOTO_ID_5138484903474512018" border="0" /></a><br />This is the bend line being set up for making a 2" wide channel. I figured out from some experimentation that my parts came out 1/32" undersize, so I needed to "steal" 1/64" or so from each flange, which is why my alignment is just a smidge to the left of the line here:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1NpSgipVms4QgICAM_Qyvm4F-yi0mxYH8dRahW2AfqOwCoPiukxR2dcIV6z209OAuoKkovr1-bLlBHA5ZKuXzTO37jKs7HgsuCMg0wvwaYMoAEjTpXxh51n3xg5m5PfvSNxQp4rc5Rg0/s1600-h/IMG_3506.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1NpSgipVms4QgICAM_Qyvm4F-yi0mxYH8dRahW2AfqOwCoPiukxR2dcIV6z209OAuoKkovr1-bLlBHA5ZKuXzTO37jKs7HgsuCMg0wvwaYMoAEjTpXxh51n3xg5m5PfvSNxQp4rc5Rg0/s400/IMG_3506.JPG" alt="" id="BLOGGER_PHOTO_ID_5137778913930264594" border="0" /></a><br />After bending, this is as far as I could go towards 90 degrees. This is due to inadequate leverage in my leaf -- I need to attach a handle:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6zHHN-sfaOrKUFYyWTtnjY4NYbHsDMaKYXUwiE8qSVlHdbU15gpjsh0_BIXsNwVCPN2-fIVV4_z1ui1gT2-eiUpiivJx_l6NH2ZHdCVq5pNMtwCuhDxCIi5z7kLfNSCtm0KJi1yjf8vI/s1600-r/IMG_3508.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZbCCooMfDGGkjBaNkRi3ltSH3M-0cBsbKDPD39otjzwbKkg5IziCwjeg9IWK2_l6K7LfUNSYC_kz6Eb3WsJhEor9R8EKM2oCUg1Di8ucZqoIuH-J9chM8d29AFFibkhrZMTM25PO1XJ8/s400/IMG_3508.JPG" alt="" id="BLOGGER_PHOTO_ID_5138484542697259138" border="0" /></a><br />But a few taps of a mallet put me all the way to a right angle. Note that the long 3/8" dia. lag bolts that you see pointing upwards and engaging the wingnuts are just about to get in the way of the channel if I bend it far enough. Also, you can't see this, but it's really pretty painful to tighten the wingnuts without mechanical assistance (hence the pliers you see), so one might as well just use regular nuts. In any case, the result is that, at one end, my channel is pretty exactly 2" wide:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1AIyjb-WUX_NcHFGgrwKZsLA7Dx7sJOx6P80GYKMZQrdqIrQ7y-mCQgX3AwIgvG1P8aMFmWtpjraAaaTLH0vsc7GBuU3PEWCvA6ivXlS-eNaX9qKt57961Mr4JEwDkBgDGESFq31IsE4/s1600-h/IMG_3516.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1AIyjb-WUX_NcHFGgrwKZsLA7Dx7sJOx6P80GYKMZQrdqIrQ7y-mCQgX3AwIgvG1P8aMFmWtpjraAaaTLH0vsc7GBuU3PEWCvA6ivXlS-eNaX9qKt57961Mr4JEwDkBgDGESFq31IsE4/s400/IMG_3516.JPG" alt="" id="BLOGGER_PHOTO_ID_5137780524543000642" border="0" /></a><br />But it's about 1/32" too small on the other end:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKu8KEEvAxBIBhv2CHsv2iJPqPpwZOJPjEuKR13jhrxlGVtTjNsq5QMiqjKM2A2N-kNG9DPMKIThZi-PwJtSLAzkLF08mUuZQMCXnc5wY06v5g3Wa4mcCzVXi_F3SbDok5NDR3LgeHGXM/s1600-h/IMG_3515.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKu8KEEvAxBIBhv2CHsv2iJPqPpwZOJPjEuKR13jhrxlGVtTjNsq5QMiqjKM2A2N-kNG9DPMKIThZi-PwJtSLAzkLF08mUuZQMCXnc5wY06v5g3Wa4mcCzVXi_F3SbDok5NDR3LgeHGXM/s400/IMG_3515.JPG" alt="" id="BLOGGER_PHOTO_ID_5137779966197252146" border="0" /></a><br />This is within spec for my (forgiving) uses, so I'm happy, though I will run some more metal through this to see how reproducible (or improveable) these results are.<br /><br />The following are the inspirations for this brake:<br /><ol><li><a href="http://www.daves601xl.com/Tools/tools.html">Dave Clay</a>'s brake, made of steel angle sections; and</li><li><a href="http://www3.sympatico.ca/murray.j/tools.htm">Murray Johnson</a>'s "Home Depot" (wood) bending brake.</li></ol>The following are the things I would/will do differently next time:<br /><ol><li>More leverage for the bending leaf;</li><li>Make all 3 working surfaces (leaf, bed and bar) out of maple;</li><li>Use larger and more durable wood screws that won't torque off;</li><li>Make the bending bar out of one wider piece of maple;</li><li>Secure the bending bar with bolts tightened from the top, as with Dave Clay's brake (above).</li></ol>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com2tag:blogger.com,1999:blog-7255819912858246321.post-14777218502389185112007-11-15T11:28:00.000-08:002007-11-15T11:44:12.621-08:00Of Recreational Vehicles and Army Navy HardwareLast Sunday, I visited my friend <a href="http://www.eastham-lee.com/rv/">Paul Eastham</a>, builder of an <a href="http://www.vansaircraft.com/public/rv-9int.htm">RV-9A</a> aircraft, at his hangar at <a href="http://www.airnav.com/airport/E16">South County</a> airport. We chatted about riveted aluminum, and went on a short trip to <a href="http://www.airnav.com/airport/KWVI">Watsonville</a> for lunch. He very generously let me take the controls and boy, I tell ya, that was a blast! He is building a camera mount, so he also took the opportunity to teach me how to drive solid rivets, and I learned about rivet smileys. :) All in all, I had a great time.<br /><br />As a parting gift, he gave me some leftover hardware (mostly AN3) to experiment with for my own projects.<br /><br />Now, meet my son, Aden. He is a nut (so to speak) for AN hardware. It was like showing a bag of diamonds to a jewel thief. He had to have an RV-9A. It had to be made of "real, lightweight" aluminum just like the real thing, and it had to be made with AN bolts. These were, so to speak, the design constraints. Here is the result:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTvHdcURhUoRyTRu7nOQFqZZ6tz6ZCDVIjmwGGuxDqLuU_1npbVSHmcN-vL5lgHikj2gfZF5Zo-4BUwCsPHyaK1_Fnh7aItAX-Iv4l-C-JtkwQQVFGQ8u-LWJcYS_IotYv4aiAam0WnZg/s1600-h/IMG_3483.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTvHdcURhUoRyTRu7nOQFqZZ6tz6ZCDVIjmwGGuxDqLuU_1npbVSHmcN-vL5lgHikj2gfZF5Zo-4BUwCsPHyaK1_Fnh7aItAX-Iv4l-C-JtkwQQVFGQ8u-LWJcYS_IotYv4aiAam0WnZg/s400/IMG_3483.JPG" alt="" id="BLOGGER_PHOTO_ID_5133154050196258786" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2C2iUeuKgggRb8nsiieRO7R8aAGuA7xM8jjyxqzzwO1BBkzHRp2DatpkdHZmE943DlUjp8DhffDutSTLsWCAIoB8zf1oqwSpaojzovFViVq8xYac2cG4ys2phjHhO4AbkTpXcQ3Gh2Rw/s1600-h/IMG_3485.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2C2iUeuKgggRb8nsiieRO7R8aAGuA7xM8jjyxqzzwO1BBkzHRp2DatpkdHZmE943DlUjp8DhffDutSTLsWCAIoB8zf1oqwSpaojzovFViVq8xYac2cG4ys2phjHhO4AbkTpXcQ3Gh2Rw/s400/IMG_3485.JPG" alt="" id="BLOGGER_PHOTO_ID_5133154432448348146" border="0" /></a><br />You may notice that it ended up being an RV-9 instead of an RV-9A. That's life, I guess. You start out trying to build one airplane, and you end up building the other. It just happens.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-22400684815215292872007-10-15T09:42:00.000-07:002007-10-15T10:02:02.322-07:00Curta calculatorYesterday, at the Harvest Festival at <a href="http://www.ebparks.org/parks/ardenwood">Ardenwood Historic Farm</a>, I saw an exhibit of antique surveying instruments. Among those was a <a href="http://curta.org/">Curta</a> mechanical calculator. Fascinating little thing. I subsequently found out that there's a <a href="http://www.vcalc.net/curta_simulator_en.htm">Curta simulator</a> in Flash; that these things go for about a kilobuck on <a href="http://search.ebay.com/search/search.dll?satitle=curta">eBay</a>; and that someone out there had the chutzpah to <a href="http://www.vcalc.net/disassy/">disassemble</a> theirs.<br /><br />Back in the early 1960s, my dad was studying at the École Nationale Supérieure de l'Aéronautique in Paris. My mother told me stories about him doing his homework late into the night, while she listened to the clicking of one of these things.<a href="http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fwww.paris-malaquais.archi.fr%2F&ei=nJkTR-yOI4i2gQO62YivCA&usg=AFQjCNGXZkf8_DTVK23NoOATNf4fRXk8YA&sig2=CxafnzD_T-8kjfiCJfSq6w" class="l" onmousedown="return rwt(this,'','','res','1','AFQjCNGXZkf8_DTVK23NoOATNf4fRXk8YA','&sig2=CxafnzD_T-8kjfiCJfSq6w')"><span style="font-size:-1;"><b></b></span></a>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-22160023723895049392007-09-29T09:54:00.001-07:002007-09-29T10:07:22.428-07:00Fragment of bracket detailI recently put together a fragment of <a href="http://schmivits.blogspot.com/2007/08/easy-racers-javelin-clone.html">this design</a> just to get a feel for how things go together. This is also the first time I'm using the <a href="http://www.aircraftspruce.com/catalog/cspages/zinc.php">Tempo zinc oxide</a> rattle can primer.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSwjjlwFTjceGEjawQmGqMp-qjx-ODDetzqWqntD06f5OXBVRITBNyLoGwRMdfn72SQ5k3NdqpVa8yf1rVDJ1b1WsAjrPXTMUdRKmLWzM0p-KnrN_y88e5qHEsGVk8_ucInflVWr1Unx4/s1600-h/IMG_3045.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSwjjlwFTjceGEjawQmGqMp-qjx-ODDetzqWqntD06f5OXBVRITBNyLoGwRMdfn72SQ5k3NdqpVa8yf1rVDJ1b1WsAjrPXTMUdRKmLWzM0p-KnrN_y88e5qHEsGVk8_ucInflVWr1Unx4/s400/IMG_3045.JPG" alt="" id="BLOGGER_PHOTO_ID_5115672285488094706" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5_bG1a9gD60bYJnej7Ns8jrzn_hlNB5rz6tOJ4pjMyAZdeHMNyYSzdOcV_V3l3o1JLs6snCYOZLjRUBa8ywfHEMxp7dou4Sn7TxsARVKLRElNjpbGcAxWEiFtrqsdYVXGvdnGlWgRHRI/s1600-h/IMG_3046.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5_bG1a9gD60bYJnej7Ns8jrzn_hlNB5rz6tOJ4pjMyAZdeHMNyYSzdOcV_V3l3o1JLs6snCYOZLjRUBa8ywfHEMxp7dou4Sn7TxsARVKLRElNjpbGcAxWEiFtrqsdYVXGvdnGlWgRHRI/s400/IMG_3046.JPG" alt="" id="BLOGGER_PHOTO_ID_5115672830948941314" border="0" /></a>Notice that the bracket, made of 1/8" thick material, is not a complete "T" shape. This is because I just happened to have a thin strip of the stuff, so I cut whatever I could and worked with what I had. This Is Only A Test.<br /><br />Notice also that I had trouble getting the primer to go on uniformly. It was scratch resistant on the sheet material, but seemed to easily de-bond from the 1/8" plate. I think the latter was because I didn't slap it on thick enough. Surface prep was to scuff with brown Scotch-Brite, wash with warm water and Dawn dish soap, dry, then apply the coating.<br /><br />You might think these random pieces of stuff I make are useless. Not so! I'll have you know that this latest creation of mine was used as a scoop to rescue a crawfish from the neighborhood street. My wife tells me that the handle on the side was helpful.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com1tag:blogger.com,1999:blog-7255819912858246321.post-6943742761821327672007-08-28T09:13:00.000-07:002007-08-28T10:07:04.124-07:00On bondageFolks have asked me about bonding (perhaps with backup rivets) versus just riveting. Elsewhere in this blog, I've mentioned that I am currently pursuing a "riveting only" strategy. The question is, "why"?<br /><br />In order to be useful, a design must fulfill a purpose, or "market" niche. The purpose need not be monetary -- the market in question may be that of making folks happy, spreading Peace and Love, or winning a competition just for the sheer challenge of the thing. In my case, my purpose is this:<br /><div style="border: 1px solid rgb(221, 221, 221); padding: 2px; background-color: rgb(255, 255, 102); margin-left: 2em;"><strong>Hypothesis 1.</strong> Traditional aircraft monocoque aluminum construction, using thin sheetmetal and large cross-sections, occupies a useful niche between welded space frames and carbon fiber monocoques. It is competitively light weight and rigid while being easy for beginners to build.</div><br />There is also another claim, less easily made:<br /><br /><div style="border: 1px solid rgb(221, 221, 221); padding: 2px; background-color: rgb(255, 255, 102); margin-left: 2em;"><strong>Hypothesis 2.</strong> The methods of Hypothesis 1 can be used as the basis for selling parts to homebuilders allowing them to design and build their own configurations.</div><br />With that in mind, the question is: should we just use plain rivets, or should we mess with bonding?<br /><br />The aircraft industry has been using rivet bonded construction for many years. Thus it is instructive to follow their trajectory. The original F-18 A-D had a multi-part metal fin. The newer E-F models have a single piece, bladder molded, heat cured composite fin. Sound familiar? Bikes like the <a href="http://www.m5-ligfietsen.nl/site/NL/Modellen/Carbon_High_Racer">M5 Carbon High Racer</a> and the <a href="http://www.velokraft.com/">Velokraft</a> bikes all use this method, as do many upright carbon frames. Clearly, if you have the equipment, this is The Future. In addition, absent bladder molding, people like Garrie Hill, <a href="http://www.jjscozzi.com/">Jim Scozzafava</a>, <a href="http://traylorfwd.home.mindspring.com/">Tom Traylor</a> and a whole host of others have shown that, if one is willing to do layups, carbon construction rules the roads. Hence, once again, the niche is to find something easier than carbon, but lighter than space frames.<br /><br />There seem to be conflicting notions out there about how much one needs to prepare a metal surface for bonding. However, among people who rely on it for a living (or whose companies will fail dramatically if their structures come apart in service), the consensus seems to be that it's not easy. Check these out for starters:<br /><ul><li><a href="http://www.loctite.com/int_henkel/loctite/binarydata/pdf/ACF205.pdf">Hysol® Surface Preparation Guide</a>, Loctite Aerospace [PDF]</li><li><a href="http://www.niar.wichita.edu/faa/FAAAB/Thursday%20Afternoon/Material%20&%20Process%20Qualification%20and%20Control/FAA%20Bonding%20Workshop_Mazza.pdf">Adhesive Bonding Surface Prep Qualification Considerations</a>, Jim Mazza, Materials and Testing Directorate, Air Force Research Laboratory [PDF]</li><li>The <a href="http://www.windcheetah.co.uk/manufacturing.htm">Windcheetah</a> manufacturing process<br /></li></ul>In general, it seems to me that proper surface prep for bonding in order to achieve the rated strength of modern epoxies involves at least lots of care, and sometimes toxic and/or caustic chemicals.<br /><br />Thus my current direction is to just rivet. Every Schmoe can build one and it will very likely stay together. It's easy to see a crappy rivet and, conversely, if a rivet looks pretty, it's probably adequately driven.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-47860272258114261982007-08-23T12:17:00.000-07:002007-08-23T12:35:32.309-07:00Easy Racers Javelin cloneMy current design is a clone of an <a href="http://www.easyracers.com/javelin.htm">Easy Racers Javelin</a>: 700c rear, 451 front, LWB. I figure this is an easy way to get started -- later on, I can try more fancy designs with integrated seats. I'm trying not to "overmodel", so here is a sketch of just the parts I need to build a simple prototype of the rear wheel attachment. I would certainly not build such a long structure to the right, but I want to give an idea of how it would fit together:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEid2iZUv0fyL2WLQyLI0s-u107cmDq7TWsNMQGFJBzhhWexmBU7XVvwtOBKmvXwRbU0JMkAjKlveuPBin3qDmTdsCtGdOSjiQqnkFGAOXa_2xx1BRPYiLU7S4tbNM1fbJ3GfciL_JYKKnM/s1600-h/toplevel-assy-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEid2iZUv0fyL2WLQyLI0s-u107cmDq7TWsNMQGFJBzhhWexmBU7XVvwtOBKmvXwRbU0JMkAjKlveuPBin3qDmTdsCtGdOSjiQqnkFGAOXa_2xx1BRPYiLU7S4tbNM1fbJ3GfciL_JYKKnM/s400/toplevel-assy-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101977644560862610" border="0" /></a>The dropout is made from 1/4" 6061-T6 plate. The stays are 5/8" diameter, .035" wall <a href="http://www.aircraftspruce.com/catalog/mepages/alumtube_2024.php">2024-T3 round drawn tubing</a>, flattened at the ends and attached with two #8 <a href="http://www.aircraftspruce.com/catalog/hapages/ms27039.php">MS27039 machine screws</a>:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqRgAY6W_EwYQy70gajj6vD8nE_yK6zBEfTbwJylsBYxfZylht89-23gxGDD9vbNv4KARtOizoHnB_kZmlDDUaLAY7-EUfmF2ucaY-8RRucc0SeidUxI7UL64qk3z8wMIJhZ7Uomzgt54/s1600-h/toplevel-assy-02.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqRgAY6W_EwYQy70gajj6vD8nE_yK6zBEfTbwJylsBYxfZylht89-23gxGDD9vbNv4KARtOizoHnB_kZmlDDUaLAY7-EUfmF2ucaY-8RRucc0SeidUxI7UL64qk3z8wMIJhZ7Uomzgt54/s400/toplevel-assy-02.jpg" alt="" id="BLOGGER_PHOTO_ID_5101977648855829922" border="0" /></a>The stays are attached to the body by (roughly T-shaped) brackets made from 1/8" thick 6061-T6 material:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgknmd5_zy44sn6qEmphESAX_-VtUCP9j2SsebIdcrAgGeHJVWTo2A0_F2RnzVudMln4oTbAv7A_t7-UaBLzrrRnUz0Y1UUOa_97RnRRQUkP69_bbwJ0AcF_2l6i2F-AY6Xd0sdGwP85B8/s1600-h/toplevel-assy-03.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgknmd5_zy44sn6qEmphESAX_-VtUCP9j2SsebIdcrAgGeHJVWTo2A0_F2RnzVudMln4oTbAv7A_t7-UaBLzrrRnUz0Y1UUOa_97RnRRQUkP69_bbwJ0AcF_2l6i2F-AY6Xd0sdGwP85B8/s400/toplevel-assy-03.jpg" alt="" id="BLOGGER_PHOTO_ID_5101977657445764530" border="0" /></a>They are held together at the middle by a spreader piece made from 1/16" 6061-T6:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiejl6JG9g2Ozr9LIw7QN8UQUxPL499649rPBMlj8Zt32SijwcfVCeeEj4naq8rtxXj8oSyGrdyE5pVwI1CzNovxhi7My0LDoFZc8Nl68kJ-JFqlI1GBhNWbWyWMXI1v6AJrZLXNerdpTY/s1600-h/stay-flange-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiejl6JG9g2Ozr9LIw7QN8UQUxPL499649rPBMlj8Zt32SijwcfVCeeEj4naq8rtxXj8oSyGrdyE5pVwI1CzNovxhi7My0LDoFZc8Nl68kJ-JFqlI1GBhNWbWyWMXI1v6AJrZLXNerdpTY/s400/stay-flange-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101977644560862594" border="0" /></a>Removing the stay and spreader piece, we can peek in to see that the 1/8" bracket is built up on each side with a 1/16" thick spacer, such that the stay is flattened on both ends to an inside dimension of 1/4". This ensures that it has a nice radius without cracking:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUCd3yfVkftaH06OOCQl8_x7ZFIL2f__fA9oRJXFZzwx_o95pA05vz2jdVjWPp59JBYrOKEzuS6Mzh6C_qaXuCLUiJdiNpd8VWLrFpwqr2s2AZlE4tRILNdDY6xhhaEPUh0SkP3GcQ8Xs/s1600-h/toplevel-assy-04.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUCd3yfVkftaH06OOCQl8_x7ZFIL2f__fA9oRJXFZzwx_o95pA05vz2jdVjWPp59JBYrOKEzuS6Mzh6C_qaXuCLUiJdiNpd8VWLrFpwqr2s2AZlE4tRILNdDY6xhhaEPUh0SkP3GcQ8Xs/s400/toplevel-assy-04.jpg" alt="" id="BLOGGER_PHOTO_ID_5101977657445764546" border="0" /></a>The approach I show here, with a thicker bracket and a stay flattened onto the bracket, is a lot simpler and more symmetrical than either <a href="http://schmivits.blogspot.com/2007/08/triangulated-stays-funky-mounting.html">riveting the stay from the sides</a> or <a href="http://schmivits.blogspot.com/2007/06/latest-riveted-aluminum-recumbent-bike.html">inserting the stays into the structure</a>. Note that I'm relying on the brackets themselves to resist side-to-side forces since the 1/8" plate has significant bending strength (though I haven't done the math on that part to know for sure, mainly because I am not sure what the design lateral loads <span style="font-style: italic;">should</span> be).<span style="text-decoration: underline;"></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUCd3yfVkftaH06OOCQl8_x7ZFIL2f__fA9oRJXFZzwx_o95pA05vz2jdVjWPp59JBYrOKEzuS6Mzh6C_qaXuCLUiJdiNpd8VWLrFpwqr2s2AZlE4tRILNdDY6xhhaEPUh0SkP3GcQ8Xs/s1600-h/toplevel-assy-04.jpg"><br /></a>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-4991216863927125202007-08-23T11:57:00.000-07:002007-08-23T12:03:09.722-07:00Early monostay designThis early monostay design was far simpler than my subsequent ones. Here is the overall view:<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcsogC8vGbCawqqzjdJURfW2M0zhaYufhsvXELZBXSLF5UZrHTqlwcNyxfV3WagtWJfweY6c-VktedZEaojuP_r9ysNm_Eiy_2xnfK6Q8QWbAwVRN7OL3HJT4tLnzPxWloNoRdUIwPzN8/s1600-h/toplevel-assy-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcsogC8vGbCawqqzjdJURfW2M0zhaYufhsvXELZBXSLF5UZrHTqlwcNyxfV3WagtWJfweY6c-VktedZEaojuP_r9ysNm_Eiy_2xnfK6Q8QWbAwVRN7OL3HJT4tLnzPxWloNoRdUIwPzN8/s400/toplevel-assy-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101972417585663298" border="0" /></a>Removing the right side skins, we can see inside. Each monostay side is made up of a top and bottom channel piece; these come together in the middle and are attached to top and bottom plates. The skins hold the whole thing to the main body of the bike.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnGWe3GIwVHusfwymegnhN4amnr9KOExQMvTwC9yr41aHIzmo75JIOX08kaAXdR2VTNhkUNFKp4bhBLlHSftAw1U4NgxeokqSKTG3xyZXTiSFSma0H8m7jectlKMr4ahyPqOxMZZ2hpgg/s1600-h/toplevel-assy-02.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnGWe3GIwVHusfwymegnhN4amnr9KOExQMvTwC9yr41aHIzmo75JIOX08kaAXdR2VTNhkUNFKp4bhBLlHSftAw1U4NgxeokqSKTG3xyZXTiSFSma0H8m7jectlKMr4ahyPqOxMZZ2hpgg/s400/toplevel-assy-02.jpg" alt="" id="BLOGGER_PHOTO_ID_5101972421880630610" border="0" /></a>Looking back, this design is somewhat appealing. Perhaps I should return to it one day.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-57673513262587852042007-08-23T11:46:00.001-07:002007-08-23T11:51:48.352-07:00Triangulated stays, funky mountingAnother remark about the design discussed earlier in <a href="http://schmivits.blogspot.com/2007/06/headtube-assembly.html">this post</a>:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdm40UQEx_WYq5AOYuKkU1Ju3bvkiLv5fCp8gC27lzuypC1IEOkOo_HfoQ_xy4n6LnbSm1jeswlToit2qMTfScWgX8xd-AkPh5Az-_LApPtJDjbFR7eOyFEQJECVIdxGGfytCenxk87vY/s1600-h/toplevel-assy-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdm40UQEx_WYq5AOYuKkU1Ju3bvkiLv5fCp8gC27lzuypC1IEOkOo_HfoQ_xy4n6LnbSm1jeswlToit2qMTfScWgX8xd-AkPh5Az-_LApPtJDjbFR7eOyFEQJECVIdxGGfytCenxk87vY/s400/toplevel-assy-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101969514187771154" border="0" /></a>Mainly, I just want to record the treatment of the stay attachment. The stays are riveted into two straps, made of 1/16" 6061-T6:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLRLUx0B2AdLNJnV177cxU15XLDrvhyphenhyphena2UCapVtTmYoXGhxOF2xOUwbJb9rowAeQKZzXp4RSPO_3ywh1kzi8uXUMTSBLMdfTdxcPwHNjyHajNENWOA-6t3WDu5hqLffNj5F_er5G0awhw/s1600-h/toplevel-assy-02.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLRLUx0B2AdLNJnV177cxU15XLDrvhyphenhyphena2UCapVtTmYoXGhxOF2xOUwbJb9rowAeQKZzXp4RSPO_3ywh1kzi8uXUMTSBLMdfTdxcPwHNjyHajNENWOA-6t3WDu5hqLffNj5F_er5G0awhw/s400/toplevel-assy-02.jpg" alt="" id="BLOGGER_PHOTO_ID_5101969514187771170" border="0" /></a>A third component, made of the same material, acts as a brace in between the stays and is riveted to the back of the bike structure to cleanly transmit side-to-side forces:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPbUpCeorui4KWNzVWzBY-SkX-DGyw780Ewslb8S1HURwjFWs9WHq9pZ7ojnEwmpXHvrMrKtDLfX5Srk0o0nYYXtQyO2D1ReJjgzwCCe_0UKvV0Kl6sZn8o2KeE5gv7Aqi2VRyTrbTjDs/s1600-h/seatstay-bracket-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPbUpCeorui4KWNzVWzBY-SkX-DGyw780Ewslb8S1HURwjFWs9WHq9pZ7ojnEwmpXHvrMrKtDLfX5Srk0o0nYYXtQyO2D1ReJjgzwCCe_0UKvV0Kl6sZn8o2KeE5gv7Aqi2VRyTrbTjDs/s400/seatstay-bracket-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101969518482738482" border="0" /></a>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-69432533721320731052007-08-23T11:39:00.000-07:002007-08-23T11:42:50.142-07:00An experiment with tubular monostaysThis was a quick experiment with tubular monostays riveted into the structure. I didn't really do any strength calculations on this; I include it here just to record the idea for posterity. Here is an overall view:<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEji4he4opkGJUQ_z30-jJH9l7x-x67pu_B3I8aexrCMrPwWkD2EhWiagjAXFFgOcT53ga0WaCtHe8a-toaB3sdK0wR86_Xsa15prJjkPquS16wBlWfEJR3HrOHNwjE3NqjTmKDPFUSl7ko/s1600-h/toplevel-assy-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEji4he4opkGJUQ_z30-jJH9l7x-x67pu_B3I8aexrCMrPwWkD2EhWiagjAXFFgOcT53ga0WaCtHe8a-toaB3sdK0wR86_Xsa15prJjkPquS16wBlWfEJR3HrOHNwjE3NqjTmKDPFUSl7ko/s400/toplevel-assy-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101967693121637602" border="0" /></a>Zooming into the attachment area and removing the side skin, we have:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXGGuo_VXwOD5TE_Q8x39lb_x2D91EojJirHAZGMKx7GNdpFIucMtNlafL5TZVpgxCuvPQLmX6-nNXklw00w6DN8gjCCl1ebl3foyKQjHS_Bf5o32vPZ-0WcabxStj7Lo-pZFsLHx-BEM/s1600-h/toplevel-assy-02.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXGGuo_VXwOD5TE_Q8x39lb_x2D91EojJirHAZGMKx7GNdpFIucMtNlafL5TZVpgxCuvPQLmX6-nNXklw00w6DN8gjCCl1ebl3foyKQjHS_Bf5o32vPZ-0WcabxStj7Lo-pZFsLHx-BEM/s400/toplevel-assy-02.jpg" alt="" id="BLOGGER_PHOTO_ID_5101967697416604914" border="0" /></a>After we remove a couple more parts, we can see the tubes nestled in there:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHJL0VoV4Q_3OEft7kKlggoXK0ZjxUGSxHcjS08EDpQCjwOI4zW_NQHzJkXnaz7LSwImEm6A84HJdC5k8tGdoFqklYxfikfl9tRzzVdzs5J02syLBY0gZ0xa30VjSg93cDeC8vTxUDBHE/s1600-h/toplevel-assy-03.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHJL0VoV4Q_3OEft7kKlggoXK0ZjxUGSxHcjS08EDpQCjwOI4zW_NQHzJkXnaz7LSwImEm6A84HJdC5k8tGdoFqklYxfikfl9tRzzVdzs5J02syLBY0gZ0xa30VjSg93cDeC8vTxUDBHE/s400/toplevel-assy-03.jpg" alt="" id="BLOGGER_PHOTO_ID_5101967697416604930" border="0" /></a>This design assumes that each tube is attached by a line of rivets on each of 3 sides (top, bottom and outboard) to achieve the necessary strength.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-52809432765218668912007-08-23T11:24:00.000-07:002007-08-23T11:30:36.959-07:00Funky design with tubular staysThis is a rather funky-looking design, again in the dual 406 SWB configuration. Note the mid drive attachment, a 1/2" diameter tube that is riveted between two bulkheads in the main structure:<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtUqMXOe1IE6YN5oqJJcAnkgikxVTzcknMG6gg18SU5N5gpRcLS6PxAkhjWUkDRxsxYUNetPQ9GL-hI0PIe7AzSzfPgBYxvlGxqSBM8wA8N8HtO45Ukv2vNrOwtLMjg0JQVnXx0qfUN60/s1600-h/toplevel-assy-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtUqMXOe1IE6YN5oqJJcAnkgikxVTzcknMG6gg18SU5N5gpRcLS6PxAkhjWUkDRxsxYUNetPQ9GL-hI0PIe7AzSzfPgBYxvlGxqSBM8wA8N8HtO45Ukv2vNrOwtLMjg0JQVnXx0qfUN60/s400/toplevel-assy-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101964033809501346" border="0" /></a>Here is the seatstay attachment. All 3 brackets are made from 1/16" 6061-T6 plate:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipdC3KcsaGMpmpDZS0hdaWAEn4T845NgwSB6jK8ldQUEItgZdlNrvcFd1d1M8064_chYAo4zu8z9w5Bzao64Mm-RuT-YOezRCJC9K8W-hRW0zBPkfFhp-c18ie7ouO4n9Z6wKwZJPYNGE/s1600-h/toplevel-assy-02.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipdC3KcsaGMpmpDZS0hdaWAEn4T845NgwSB6jK8ldQUEItgZdlNrvcFd1d1M8064_chYAo4zu8z9w5Bzao64Mm-RuT-YOezRCJC9K8W-hRW0zBPkfFhp-c18ie7ouO4n9Z6wKwZJPYNGE/s400/toplevel-assy-02.jpg" alt="" id="BLOGGER_PHOTO_ID_5101964038104468658" border="0" /></a>And here is the chainstay attachment. The main bike structure is extended backwards a bit to avoid making the stays too long, on the theory that the large rectangular cross-section monocoque is more rigid and lighter than the stays, so we use it as far as we can till we get very close to the wheel:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQRJXCFeMg5X2H8wc8INKrkiWf7qYWDFUQyxJjd72uujNb5CkNEmoubl78K561fgkA_EYPIzrjJ7LfPWcxTO1GBRrHQS-QNPjlIsHCrPYu9J_hcmLhKYwsUKz_wKSdWpdU-Z1_v7D5EDU/s1600-h/toplevel-assy-03.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQRJXCFeMg5X2H8wc8INKrkiWf7qYWDFUQyxJjd72uujNb5CkNEmoubl78K561fgkA_EYPIzrjJ7LfPWcxTO1GBRrHQS-QNPjlIsHCrPYu9J_hcmLhKYwsUKz_wKSdWpdU-Z1_v7D5EDU/s400/toplevel-assy-03.jpg" alt="" id="BLOGGER_PHOTO_ID_5101964042399435970" border="0" /></a>Removing the right hand mounting bracket and skin, we get a clearer view into the structure:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9qZG5db4fuBPmUIkyhpI4TitWowvGW-WaprTx5Wz9mmC3F3vxO-jlV3MtNNojaO4sdPJKZDqzWk_6EOoafEs83QgTeNtB7C1LGN2z1EPvtZFUcC7ZILyRwNEih0jx9vEzbO5_jOjetEM/s1600-h/toplevel-assy-04.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9qZG5db4fuBPmUIkyhpI4TitWowvGW-WaprTx5Wz9mmC3F3vxO-jlV3MtNNojaO4sdPJKZDqzWk_6EOoafEs83QgTeNtB7C1LGN2z1EPvtZFUcC7ZILyRwNEih0jx9vEzbO5_jOjetEM/s400/toplevel-assy-04.jpg" alt="" id="BLOGGER_PHOTO_ID_5101964046694403282" border="0" /></a>Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-36752252321581170102007-08-23T10:33:00.000-07:002007-08-23T12:09:48.239-07:00Full monocoque monostay designPerhaps the most complex of my riveted aluminum recumbent designs is this one, the culmination of a whole bunch of experimenting with parts and CAD work. The whole structure you see here (not including the wheels) weighs 5.02 pounds.<br /><br />Here are two SolidWorks renderings and one snapshot from the regular line view.<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMWwX20Guyx6_7RakoSx2c8_XvJRYrWwrt9TZ6QXqsGG0nB2rNX1LcflbUcWMxLj87W_k4eS6ZC4MwDfDTrLUt_Zoekbd-GMvqFo75UJtLoloqEYRZEl8Oh6IVoEkA8tJ1Y2KVwsYE9us/s1600-h/render-01.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMWwX20Guyx6_7RakoSx2c8_XvJRYrWwrt9TZ6QXqsGG0nB2rNX1LcflbUcWMxLj87W_k4eS6ZC4MwDfDTrLUt_Zoekbd-GMvqFo75UJtLoloqEYRZEl8Oh6IVoEkA8tJ1Y2KVwsYE9us/s400/render-01.png" alt="" id="BLOGGER_PHOTO_ID_5101951020058594226" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlkC7M3IP0raO5-l_zY5xWbjSmmiFuz0TPNBfm5jnEtMpnAS9psBSHez93TsS3GDnAsTrONRSP9hxNzJCHdTWBKnjcw6_ZfH6t6ltkQ_43k-8vOdk9g40QimxrIbPPC8m1z8XZ-TopVVA/s1600-h/render-02.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlkC7M3IP0raO5-l_zY5xWbjSmmiFuz0TPNBfm5jnEtMpnAS9psBSHez93TsS3GDnAsTrONRSP9hxNzJCHdTWBKnjcw6_ZfH6t6ltkQ_43k-8vOdk9g40QimxrIbPPC8m1z8XZ-TopVVA/s400/render-02.png" alt="" id="BLOGGER_PHOTO_ID_5101951093073038274" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGVyGU16T-cYCRL-n7fWfEt7PVepHlK2vv6-0NuWB9jmr9wGsRktFTqGRGPp6LKE6mIn4Nz0fSlnYosamGad8mXWW7XZD8o5fZuZZwjjImdmZrpOCAL_IYA6dZSsCyGhlwfQEJF06EgnQ/s1600-h/new-toplevel-assy-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGVyGU16T-cYCRL-n7fWfEt7PVepHlK2vv6-0NuWB9jmr9wGsRktFTqGRGPp6LKE6mIn4Nz0fSlnYosamGad8mXWW7XZD8o5fZuZZwjjImdmZrpOCAL_IYA6dZSsCyGhlwfQEJF06EgnQ/s400/new-toplevel-assy-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101951144612645842" border="0" /></a>The way I build these assemblies, I generally construct a "part" that contains just pure geometry, containing most of the important driving dimensions and shapes for the rest of the work. The hope (rarely achieved in practice but true for some things) is that a change to the geometry causes the parts to automatically rearrange and resize themselves:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdAbiuV8S0XNE02stuf9udgeHWtM7D-BkzKpXJTNR3h-IeiP2yILM5E5L7pSW7VLliHMOvT55Pn71fYSlPcLJDhYti0F3VaKHzEA5OhBJK58-eZCK_aOa5xavl2-scDMSmYqvUgo4GKBg/s1600-h/geometry-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdAbiuV8S0XNE02stuf9udgeHWtM7D-BkzKpXJTNR3h-IeiP2yILM5E5L7pSW7VLliHMOvT55Pn71fYSlPcLJDhYti0F3VaKHzEA5OhBJK58-eZCK_aOa5xavl2-scDMSmYqvUgo4GKBg/s400/geometry-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101957943545875602" border="0" /></a>The design is a dual 406 SWB. The seat is a sheet of plywood, while the remainder is riveted .025" 2024-T3 Alclad sheet with fittings made of 6061-T6. Zoomed in on the front, with the side skin removed, we have:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9i2pia3ivfNX6cC716K-Lt1iPBh-pGitRTLUVuR6GqyGIKOsrC3xksEpnfOMqsNjp1GILw13OP3eMfdqsXLMi4idM2fkMZn-YB7k0kB8sP91b_MLdPGx-LMIMl5cq_snFd7UuQb4x6wM/s1600-h/new-toplevel-assy-03.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9i2pia3ivfNX6cC716K-Lt1iPBh-pGitRTLUVuR6GqyGIKOsrC3xksEpnfOMqsNjp1GILw13OP3eMfdqsXLMi4idM2fkMZn-YB7k0kB8sP91b_MLdPGx-LMIMl5cq_snFd7UuQb4x6wM/s400/new-toplevel-assy-03.jpg" alt="" id="BLOGGER_PHOTO_ID_5101952205469567986" border="0" /></a>The headtube mounting assembly is previously documented in <a href="http://schmivits.blogspot.com/2007/06/headtube-assembly.html">this post</a> so I won't belabor it further. The adjustable bottom bracket assembly is made of 2x2", 1/8" wall 6061-T6 tubing and 1/8" 6061-T6 plate. This was a trial design to see how far I could go without any welding at all; everything is held together using machine screws. Here is a detail of this area:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcpRGe2ZNEHD4-EOsvHi5ckWEgBYEWx1W_oXa1phFEls3sINmrsEdHYq0u1ERsyectIaNOqAIIhjLp_7d_3kAP1MNjISrAqVLPnfaSTmymMmvv1XGPwu05Zf9LkFCckUn-u16PK5TIrn4/s1600-h/new-toplevel-assy-02.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcpRGe2ZNEHD4-EOsvHi5ckWEgBYEWx1W_oXa1phFEls3sINmrsEdHYq0u1ERsyectIaNOqAIIhjLp_7d_3kAP1MNjISrAqVLPnfaSTmymMmvv1XGPwu05Zf9LkFCckUn-u16PK5TIrn4/s400/new-toplevel-assy-02.jpg" alt="" id="BLOGGER_PHOTO_ID_5101952205469567970" border="0" /></a>I suspect the middle part of the rail could be machined (or simply drilled with lightening holes) to save a bunch of weight. Here's an example from a different design to illustrate:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKpiSV_uXhxyNXsjZqCUJed1j-skQ3Iy-UE6KzW5zwgZrgU6SyFPEIOfHtya8bWuhtcgcSWzZT6qqVIQwJTHg2_boSQO0jdZGUkDKwCmQoIMSqWXiCutV2JYKEj_hdK-TND-d6STFXsCk/s1600-h/toplevel-assy-02.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKpiSV_uXhxyNXsjZqCUJed1j-skQ3Iy-UE6KzW5zwgZrgU6SyFPEIOfHtya8bWuhtcgcSWzZT6qqVIQwJTHg2_boSQO0jdZGUkDKwCmQoIMSqWXiCutV2JYKEj_hdK-TND-d6STFXsCk/s400/toplevel-assy-02.jpg" alt="" id="BLOGGER_PHOTO_ID_5101975114825125234" border="0" /></a><br />The main emphasis of this design was to investigate how I could "use the monocoque, Luke": my goal was to build as much of the primary structure as possible using the monocoque, eschewing tubular stays. First, a view of the overall structure with the monostay assembly and only the skeleton of the rest of the structure, to give some perspective:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDc90XEhyphenhyphenG5SMzZqAmXI61BfJL3B8qTK9pyx3-zvxZbqPFjtFPbv1iX9HLfqphbpJrVInYv2ut7HmsLO8UlQ7Tgvgr_msKAiHLLVi5v_pWL2ysxJIvafTQ6rfafGKnv8454Sbn4KxzkRQ/s1600-h/new-toplevel-assy-04.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDc90XEhyphenhyphenG5SMzZqAmXI61BfJL3B8qTK9pyx3-zvxZbqPFjtFPbv1iX9HLfqphbpJrVInYv2ut7HmsLO8UlQ7Tgvgr_msKAiHLLVi5v_pWL2ysxJIvafTQ6rfafGKnv8454Sbn4KxzkRQ/s400/new-toplevel-assy-04.jpg" alt="" id="BLOGGER_PHOTO_ID_5101952209764535298" border="0" /></a>When the rest of the skeleton is removed, we can see that parts of the monostay assembly extend into, and intersect, the main structure:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjl-UjwZdkb7_GQ_SWhZE-PbR96WpgTsJExMqmPiN5XoSRcuHMqcxaipT8YPr34BSE-YVe_V6CVfORmd7qioRN3hitKQfJss9lWP78Noqhnulbkdav7nZUHkpZ6gzDOm4r7Hc3r-cyOjG0/s1600-h/new-toplevel-assy-05.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjl-UjwZdkb7_GQ_SWhZE-PbR96WpgTsJExMqmPiN5XoSRcuHMqcxaipT8YPr34BSE-YVe_V6CVfORmd7qioRN3hitKQfJss9lWP78Noqhnulbkdav7nZUHkpZ6gzDOm4r7Hc3r-cyOjG0/s400/new-toplevel-assy-05.jpg" alt="" id="BLOGGER_PHOTO_ID_5101952214059502610" border="0" /></a>Removing one side skin and the two doublers on the dropout end, we can peek into the structure:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR4yPwCqEH-R2B-N2djHga5ygz9lZmM1XhW-q1jCwf9H7_BdlzgnDzvztI_mzDRvaUp0VSdDB8_dwfvZ4v9_DgythNkIlFDtpmRFQoEiHQ0ksCcXzdUQ_eDDzB_e5ZUoh1kMItp1BA-L4/s1600-h/new-toplevel-assy-06.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR4yPwCqEH-R2B-N2djHga5ygz9lZmM1XhW-q1jCwf9H7_BdlzgnDzvztI_mzDRvaUp0VSdDB8_dwfvZ4v9_DgythNkIlFDtpmRFQoEiHQ0ksCcXzdUQ_eDDzB_e5ZUoh1kMItp1BA-L4/s400/new-toplevel-assy-06.jpg" alt="" id="BLOGGER_PHOTO_ID_5101952218354469922" border="0" /></a>Removing the two long channel sections that come out towards the viewer, we have:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJzebJu78CuHxlxVRcnsAdjdf9zwpCumYB2LoloncFwgVHBXQGCsKvzgIPYHOFunIpS5hHuUXQhsMHFWdqjBWLkS3gt_ksjzbxOzKDg7qABBbGCyfqf2a9E4lA4Y_-0ee1kRSYx-LfZik/s1600-h/new-toplevel-assy-07.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJzebJu78CuHxlxVRcnsAdjdf9zwpCumYB2LoloncFwgVHBXQGCsKvzgIPYHOFunIpS5hHuUXQhsMHFWdqjBWLkS3gt_ksjzbxOzKDg7qABBbGCyfqf2a9E4lA4Y_-0ee1kRSYx-LfZik/s400/new-toplevel-assy-07.jpg" alt="" id="BLOGGER_PHOTO_ID_5101955263486282818" border="0" /></a>and removing one more part, we have this:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg507vx7660ELZe69sOzGg6Mhp4iNkTdLcjbaRHDuSCGiQC18R58DfAQ-Su3TzjVIGReIBinHFitcSWkXFlLX7RubzEAF5o3HQjJu1Jg8SXYeFbdKz25ON-dbG9hSNfBKbSAJN4gtZglAI/s1600-h/new-toplevel-assy-08.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg507vx7660ELZe69sOzGg6Mhp4iNkTdLcjbaRHDuSCGiQC18R58DfAQ-Su3TzjVIGReIBinHFitcSWkXFlLX7RubzEAF5o3HQjJu1Jg8SXYeFbdKz25ON-dbG9hSNfBKbSAJN4gtZglAI/s400/new-toplevel-assy-08.jpg" alt="" id="BLOGGER_PHOTO_ID_5101955267781250130" border="0" /></a>which should explain pretty well how things come together. The one part we just removed is what I call the "stay fork"; this one:<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggwNs9_tpH7eWOChkiILDb8v4DDKbxYj9LOGAaERDm0RrL2eD6OboDBg3DkYXT2rQyzwZjfGQA0A5TD57YFuy42Br85LZoobDv9eaHQbs-LH9WcSXlLGBMQXnC5IB6mgWSOYWdmQ5WhPs/s1600-h/stay-fork-01.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggwNs9_tpH7eWOChkiILDb8v4DDKbxYj9LOGAaERDm0RrL2eD6OboDBg3DkYXT2rQyzwZjfGQA0A5TD57YFuy42Br85LZoobDv9eaHQbs-LH9WcSXlLGBMQXnC5IB6mgWSOYWdmQ5WhPs/s400/stay-fork-01.jpg" alt="" id="BLOGGER_PHOTO_ID_5101956513321766002" border="0" /></a>This proved to be a very difficult part to fabricate: in some parts near the "knee" of each leg, where it got pretty thin, the material kept cracking. Which led me to one important realization: parts are easier to draw than to make. One of the dangers of 3D parametric CAD such as SolidWorks is that one can go to town drawing complicated things that all auto-update whenever a dimension is changed, and have lovely geometries, but which are essentially unbuildable. :)Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-79125030547197306032007-06-24T21:30:00.000-07:002007-06-25T08:08:06.833-07:00Headtube assemblyThis is my first attempt to record some old-ish (maybe 1.5 years ago) work. Here is a rendering of one of my riveted aluminum recumbent bike designs:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhX1PINar2tCiiWKCNApR-k741WGhATGUlpT7XC5QgUXC0et3pgbb7nqEMRvas1kKEwoM1xxdrIbeTFcWRaFzpOa5p1eqS2PlmpfFiKGpsaDAhDLhQL6ftTU0TrJOQZto0W9Gc-dz7NNrI/s1600-h/overall-view.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhX1PINar2tCiiWKCNApR-k741WGhATGUlpT7XC5QgUXC0et3pgbb7nqEMRvas1kKEwoM1xxdrIbeTFcWRaFzpOa5p1eqS2PlmpfFiKGpsaDAhDLhQL6ftTU0TrJOQZto0W9Gc-dz7NNrI/s400/overall-view.jpg" alt="" id="BLOGGER_PHOTO_ID_5079855304181940242" border="0" /></a><br />and here it is with the side skins removed for illustration:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEJA9W7XfrXIvaJwTLewRWzSZJpnBAjsKd8XbdGZ6QT-LHXoAG2YtpWxbCEQBfrtLUGv_vT0vY9XbyzmU4mSMyXT4tkghc4dvx-5sIddWuRvypawDE2kXeUf0tbGOubxhNZ5uOI5xBCyg/s1600-h/skins-removed.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEJA9W7XfrXIvaJwTLewRWzSZJpnBAjsKd8XbdGZ6QT-LHXoAG2YtpWxbCEQBfrtLUGv_vT0vY9XbyzmU4mSMyXT4tkghc4dvx-5sIddWuRvypawDE2kXeUf0tbGOubxhNZ5uOI5xBCyg/s400/skins-removed.jpg" alt="" id="BLOGGER_PHOTO_ID_5079855514635337762" border="0" /></a><br />This was back when I was thinking of using rivet bonded, rather than just riveted, construction. I planned to use <a href="http://www.google.com/search?source=ig&hl=en&q=scotch-weld+dp460&btnG=Google+Search">3M Scotch-Weld DP460</a> adhesive, and the seat was to be a sandwich of <a href="http://www.rohacell.com/">Rohacell</a> structural plastic foam bonded between two very thin layers of aluminum. The only subassembly I actually constructed was the headtube mounting, shown here in CAD:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLPeGvKTzFcRlNigL7h-fqCl2twnKw3q78971SaqM0fa6-pJP39y73fKQHtQNlfsL7qcuSoOlnHvfMQuJUhUiqFrTHjnrFsuyH4dDVeMxhAuLE6SrlHfIBxXzDQBVUNyCCfLokVLRVtwo/s1600-h/headtube-assy-alone.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLPeGvKTzFcRlNigL7h-fqCl2twnKw3q78971SaqM0fa6-pJP39y73fKQHtQNlfsL7qcuSoOlnHvfMQuJUhUiqFrTHjnrFsuyH4dDVeMxhAuLE6SrlHfIBxXzDQBVUNyCCfLokVLRVtwo/s400/headtube-assy-alone.jpg" alt="" id="BLOGGER_PHOTO_ID_5079856506772783154" border="0" /></a><br />The parts are primed with <a href="http://www.google.com/search?source=ig&hl=en&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;q=cortec+373&btnG=Google+Search">Cortec 373</a> (thanks to <a href="http://www.centurycorrosion.com/">Century Corrosion</a> for arranging for a sample to be sent to me) prior to final assembly. The primer provides bonding support and corrosion resistance, and is non-toxic. However, the stuff is a bit hard to apply, and I was not able to get a uniform coat. Here is the final result:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEyc_X0h52zRDNL_9Ul_Kxd38RgrOXX5ZwCJg6fF1jWn6v7PTNo4qEnqiCSO_QGl8TXeQ5RySrJ3XL14-UilcuQNgLmiN0SsYI8lHHBGH3mjrCDLwvbBPPvjZpNd4Ojr6kKsKqB-EcNBM/s1600-h/IMG_2326.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEyc_X0h52zRDNL_9Ul_Kxd38RgrOXX5ZwCJg6fF1jWn6v7PTNo4qEnqiCSO_QGl8TXeQ5RySrJ3XL14-UilcuQNgLmiN0SsYI8lHHBGH3mjrCDLwvbBPPvjZpNd4Ojr6kKsKqB-EcNBM/s400/IMG_2326.JPG" alt="" id="BLOGGER_PHOTO_ID_5079859040803487810" border="0" /></a><br />As you might be able to see, the headtube has 4 flat surfaces providing solid surfaces for bonding and fastening into the sheetmetal. Lacking access to a machine shop, I improvised a jig from some hardware store metal and filed it down; it took several nights, and I would never, ever attempt this again, but I was finally done.<br /><br />I used 3/32" stainless steel POP rivets, and #2 stainless steel machine screws (yes, #2 -- these little guys are small -- but, in this design, all they do is stabilize the bonded joints to let the adhesive do its work). The screws are countersunk from the <span style="font-style: italic;">inside </span>of the tube to provide clearance for the steerer (sorry for the blurry pic):<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwCZW_Z78kZoEv0S9djQucI8BCAUBqXLklcPd10JHpjmmjOfs2MaibM_rTWAVpTT36NKHu2rsptI-lqfhC0QcQIUQDTUNAVg6TnXphjO3yJSWfSdXsw6ItOqyMYXAdHjFxj610OhQj9IE/s1600-h/IMG_2329.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwCZW_Z78kZoEv0S9djQucI8BCAUBqXLklcPd10JHpjmmjOfs2MaibM_rTWAVpTT36NKHu2rsptI-lqfhC0QcQIUQDTUNAVg6TnXphjO3yJSWfSdXsw6ItOqyMYXAdHjFxj610OhQj9IE/s400/IMG_2329.JPG" alt="" id="BLOGGER_PHOTO_ID_5079860436667859026" border="0" /></a><br />and this feat is accomplished by my handy reverse (aka <span style="font-style: italic;">back</span>) countersink <a href="http://www.browntool.com/productselect.asp?ProductID=295">cutter</a> and <a href="http://www.browntool.com/productselect.asp?ProductID=271">pilot</a> (tools I didn't even know existed till I needed them). Here is one more view for completeness:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUvcbbtRXVCWasZ2lt0UriWgxt8dcNl1SXTxFtp1KIFeTb5naXaDRRfGLDGbd7hXCf8qyNfc_hCpUr8ALpEX0h37NqRjKY-prScrkUGNNNR8LNZ2eCWHcLic1k_rfwPX-4HfnLNZ35KkM/s1600-h/IMG_2334.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUvcbbtRXVCWasZ2lt0UriWgxt8dcNl1SXTxFtp1KIFeTb5naXaDRRfGLDGbd7hXCf8qyNfc_hCpUr8ALpEX0h37NqRjKY-prScrkUGNNNR8LNZ2eCWHcLic1k_rfwPX-4HfnLNZ35KkM/s400/IMG_2334.JPG" alt="" id="BLOGGER_PHOTO_ID_5079862639986081890" border="0" /></a><br />Lessons learned:<br /><ol><li>Rivet bonding is tricky business. The adhesive is gooey and sticks to everything, and you have to quickly get all your parts assembled and riveted within the work time of the adhesive or else you have an ugly piece of scrap. It's all a bit stressful.<br /></li><li>Did I mention that the adhesive sticks to everything? This stuff is amazing. And it dries hard and tough as nails. I tried some test pieces, ripping them apart with my hands, to get an idea of how strong it is and, subjectively, that stuff is serious.</li></ol>More broadly, this launched me into some navel-gazing regarding the use of bonding versus just riveting. In favor of bonding, I get more rigid joints and better strength. But the flip side is the stress of having to get the surface preparation just right or else the glue doesn't stick, and the stress of assembling everything on a strict time limit while the glue hardens. And my whole idea is to devise a construction technique that can be built without fuss (or else, why not just do a carbon fiber layup and be done with it?). As a result, my subsequent designs have moved progressively away from bonding towards pure riveting.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com0tag:blogger.com,1999:blog-7255819912858246321.post-2362462046761753322007-06-23T18:01:00.001-07:002007-06-24T17:52:45.946-07:00Latest riveted aluminum recumbent bike partThis is the first of what I hope will be a series of posts describing my work to come up with a simple technique for building recumbent bicycles out of riveted aluminum. Some of these posts will work backwards in time since I have a backlog of un-blogged material (parts and CAD designs), but I'll start with the latest thing I've been working on.<br /><br />Here is a hypothetical chunk of a riveted aluminum recumbent, held against my Volae Expedition to give you an idea of where it would fit. The boxy part is supposed to be the "body" of the recumbent, forming part of the seat. The tubes sticking out are the seatstays attached to the body:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZuP1FjqR9yOs0MFqKInzeyN0q0TBBmAKegRmk2QfN4L2j30ITKot-23u0EMzmcSWlFEZBMezSTxCtAvHdJ7EbYSG-Y44GfYkY_CcBiD6LvJghPX87cnfw1HrdK9n4YoZebHHyECmNPS8/s1600-h/IMG_2321.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZuP1FjqR9yOs0MFqKInzeyN0q0TBBmAKegRmk2QfN4L2j30ITKot-23u0EMzmcSWlFEZBMezSTxCtAvHdJ7EbYSG-Y44GfYkY_CcBiD6LvJghPX87cnfw1HrdK9n4YoZebHHyECmNPS8/s400/IMG_2321.JPG" alt="" id="BLOGGER_PHOTO_ID_5079434367322160978" border="0" /></a><br />This work started with a simple sketch on dead trees. Yes, I've done the CAD thing for a while (using SolidWorks), but I spent literally hundreds of hours futzing around with minor 3D modeling details, so my current strategy is, "don't touch the computer":<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9uYkj269QtiWdIewbLWOLVuxeI9sd9PtXxaa6SI29W_Ebjg0Sk9vU8WaLO7qSgC9g-pckpxh9HYS-ZRW0p7-0M_jT7e9UUlW9-Ldp-1BP9wYCq2LBODwmL4lhsyL5v1BiT2dz_Oqdbpo/s1600-h/IMG_2325.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9uYkj269QtiWdIewbLWOLVuxeI9sd9PtXxaa6SI29W_Ebjg0Sk9vU8WaLO7qSgC9g-pckpxh9HYS-ZRW0p7-0M_jT7e9UUlW9-Ldp-1BP9wYCq2LBODwmL4lhsyL5v1BiT2dz_Oqdbpo/s400/IMG_2325.JPG" alt="" id="BLOGGER_PHOTO_ID_5079439959369580386" border="0" /></a><br />The first step is to build join the "seatstays" into a flat assembly with the proper spacing. Let's pretend that this is it:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmqKUcnDu4WRP2pGAW7mXUu-4oc3yxo7JWqfwxRZrvknqXZ6FEGX-rcUMWzMvt3Fs9Bw3KGLM4hi24f9F5GX4onZIFtaYLj0ijZmIHq80bTTv726l-aY6Q3PudrVqH96P965lksSgZXx0/s1600-h/IMG_2235.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmqKUcnDu4WRP2pGAW7mXUu-4oc3yxo7JWqfwxRZrvknqXZ6FEGX-rcUMWzMvt3Fs9Bw3KGLM4hi24f9F5GX4onZIFtaYLj0ijZmIHq80bTTv726l-aY6Q3PudrVqH96P965lksSgZXx0/s400/IMG_2235.JPG" alt="" id="BLOGGER_PHOTO_ID_5079442218522378098" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivQyLw9CZmVEhKpjpu-dY9WWCcyzo9spvYFdqH0wakCpORQu3wMkA2SR1UyKDVDozLX0o1yz0kk1Fzd9T6X7vwZ499ySkl3sONvCHII-YSYqi6uwJoo1FZw_slhikrvohjs0YbkPveMv8/s1600-h/IMG_2236.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivQyLw9CZmVEhKpjpu-dY9WWCcyzo9spvYFdqH0wakCpORQu3wMkA2SR1UyKDVDozLX0o1yz0kk1Fzd9T6X7vwZ499ySkl3sONvCHII-YSYqi6uwJoo1FZw_slhikrvohjs0YbkPveMv8/s400/IMG_2236.JPG" alt="" id="BLOGGER_PHOTO_ID_5079442733918453634" border="0" /></a><br />The tubes are 1/2" diameter aluminum from the hardware store (I didn't want to wait for an online order). The brackets in between are .025" 2024-T3 Alclad. By assembling these on a flat jig, I can ensure that the distance between the tubes is exactly 2". I used 3/32" stainless steel POP rivets.<br /><br />Next, I built the "box" with a slot for the seat tube assembly to be inserted:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcoS4N2GAm7_DVXFc2FXim5IycYX2rf0MBC8uRyuJEhTSfzqC_xW1OpWncT8abS6HbOH8Vh0BbvyLbs_MxfnQUgnfty-yNRUpqStku8MstVKPjJdOaaBueoQrR6n_BJR3fZ4k_AWjHrn8/s1600-h/IMG_2237.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcoS4N2GAm7_DVXFc2FXim5IycYX2rf0MBC8uRyuJEhTSfzqC_xW1OpWncT8abS6HbOH8Vh0BbvyLbs_MxfnQUgnfty-yNRUpqStku8MstVKPjJdOaaBueoQrR6n_BJR3fZ4k_AWjHrn8/s400/IMG_2237.JPG" alt="" id="BLOGGER_PHOTO_ID_5079443511307534226" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq1Ho1FP-8BhYjs143BmAG_TOWJIrjzRRfW9yZMmtYdxwrlBSuhygoCaRo0an0e1gn7ukV-b5O4QZLkYRlc0ze-REeF9UeWsGY7OTQ2xhlM3MTzJz-6xUnZ_8phlS29DWIGUR51dx3PsE/s1600-h/IMG_2238.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq1Ho1FP-8BhYjs143BmAG_TOWJIrjzRRfW9yZMmtYdxwrlBSuhygoCaRo0an0e1gn7ukV-b5O4QZLkYRlc0ze-REeF9UeWsGY7OTQ2xhlM3MTzJz-6xUnZ_8phlS29DWIGUR51dx3PsE/s400/IMG_2238.JPG" alt="" id="BLOGGER_PHOTO_ID_5079443897854590882" border="0" /></a><br />This box is also made on a flat jig -- there are no fancy 3D fixtures needed to hold everything in alignment. The two channel sections that form the frame, and the skin doublers that bridge the gap between the channels, are made from .025" 2024-T3 Alclad, while the side skins are .016". (Picky rivet geeks will notice a couple of edge distance boo-boos.)<br /><br />The next step is to mate these two parts. Presumably, this would happen when the builder completes the body and chainstay and seatstay assemblies. The three assemblies would be clamped to one another and to the dropouts, with an accurately dished wheel, and some 2x4s would be used to align everything <a href="http://mark.rehorst.com/CF_Bike/frame_jig.JPG">like this example</a>. The seatstay tubes can now be match drilled through the pilot holes in the side skins to fix the alignment:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5nBvs6-ZnkJghj2Ao4XFyqOZ2ZclgNAmOFILB5o1uEy-pZ-3heaP30KetaQIbCx0g6h8h_NOxcXLu69_aV8-ya0gInQ5JHw_MxJBID2SYLI-nGSHCFDOGMt_2pyNFV4-_codhhmxpxVU/s1600-h/IMG_2241.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5nBvs6-ZnkJghj2Ao4XFyqOZ2ZclgNAmOFILB5o1uEy-pZ-3heaP30KetaQIbCx0g6h8h_NOxcXLu69_aV8-ya0gInQ5JHw_MxJBID2SYLI-nGSHCFDOGMt_2pyNFV4-_codhhmxpxVU/s400/IMG_2241.JPG" alt="" id="BLOGGER_PHOTO_ID_5079446238611767218" border="0" /></a><br />The next step is to add some shear ties to the assembly, maintaining the continuity of the body around the slot and transmitting shear resulting from side-to-side forces to the body:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjugzLTgKjIVT281j54NYBcNxwxPquhA159vaN3tmh2quB4G_t001YFEMm4daExwJfY4B2fO-WF9-83srAfZhmEs0msOMQ3qL3_h7EakgWSvUBXkW4H1C2JHjIcU3-vAPELUx5te0ZfzXU/s1600-h/IMG_2249.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjugzLTgKjIVT281j54NYBcNxwxPquhA159vaN3tmh2quB4G_t001YFEMm4daExwJfY4B2fO-WF9-83srAfZhmEs0msOMQ3qL3_h7EakgWSvUBXkW4H1C2JHjIcU3-vAPELUx5te0ZfzXU/s400/IMG_2249.JPG" alt="" id="BLOGGER_PHOTO_ID_5079447479857315778" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimchKMgRrvvel2xQw8MfAD38hL2l-jN9cVatsmj1raNUSazMbphu07pVMZ3hWrE1XlA1n8zpc-TrvdtZIJd1CWPCFGhyWeSM63O-gehG0-0uOIUcveCNKlwKKFOnfNJK6MiQLKrrxnXO8/s1600-h/IMG_2251.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimchKMgRrvvel2xQw8MfAD38hL2l-jN9cVatsmj1raNUSazMbphu07pVMZ3hWrE1XlA1n8zpc-TrvdtZIJd1CWPCFGhyWeSM63O-gehG0-0uOIUcveCNKlwKKFOnfNJK6MiQLKrrxnXO8/s400/IMG_2251.JPG" alt="" id="BLOGGER_PHOTO_ID_5079448119807442898" border="0" /></a><br />If you look at the following picture, you'll notice, as I did, that the structure is missing an extra shear tie between the stays to maintain proper continuity of the monocoque. Filed under "note to self":<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCcatTqPhzmKsB1_hMmj9NiYo4z6ihJ89VObrgqlurvJlPnsakKLpRjO3OUX2x-0CN6FP0iTb6dT2FFgXtlgBuKrfzbtEa7ewcaPW6s73hn_nztxmRUlbKA40X0VVylucsbIBqjNgFr08/s1600-h/IMG_2254.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCcatTqPhzmKsB1_hMmj9NiYo4z6ihJ89VObrgqlurvJlPnsakKLpRjO3OUX2x-0CN6FP0iTb6dT2FFgXtlgBuKrfzbtEa7ewcaPW6s73hn_nztxmRUlbKA40X0VVylucsbIBqjNgFr08/s400/IMG_2254.JPG" alt="" id="BLOGGER_PHOTO_ID_5079450091197431778" border="0" /></a><br />The last step is to fabricate a cover for the other side. This will presumably be the surface to which the seat (perhaps made of plywood) would be attached. Here it is match drilled, primed and ready to rivet:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglaJ6oXFI90XWySvtyAN4pfnl948sE3tuWGOC_QxhBBgn8_YPyBCRNChJIt3tf6tbNpAabhOqjS8A6BGtztQfhE25VnsSZ8yohNbeRZiWGN_vIOSBHtIOPOaEreBLiUjf0n75pY5bCP4A/s1600-h/IMG_2315.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglaJ6oXFI90XWySvtyAN4pfnl948sE3tuWGOC_QxhBBgn8_YPyBCRNChJIt3tf6tbNpAabhOqjS8A6BGtztQfhE25VnsSZ8yohNbeRZiWGN_vIOSBHtIOPOaEreBLiUjf0n75pY5bCP4A/s400/IMG_2315.JPG" alt="" id="BLOGGER_PHOTO_ID_5079450095492399090" border="0" /></a><br />(Yes, a couple more edge distance boo-boos.) The finished product looks like this:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih3qNWFzDlL8fDYBhlXAfXUSuUFdWMVsefpz6BjJjY605By8gFzxDYvp79XjQoBW6bnSatG2EdTP3_B8Awp8rCXh_VQkXBO0y-NwIbVBKIWc4UDmIG9svUpaku2vI7GQE1_vzMDFmlTts/s1600-h/IMG_2316.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih3qNWFzDlL8fDYBhlXAfXUSuUFdWMVsefpz6BjJjY605By8gFzxDYvp79XjQoBW6bnSatG2EdTP3_B8Awp8rCXh_VQkXBO0y-NwIbVBKIWc4UDmIG9svUpaku2vI7GQE1_vzMDFmlTts/s400/IMG_2316.JPG" alt="" id="BLOGGER_PHOTO_ID_5079451830659186690" border="0" /></a><br />The craftsmanship on some of these parts leaves a little to be desired. You'll notice, in addition to the edge distance mistakes, some scratching where I accidentally pushed the drill too far through the structure, and a few parts that were made a bit skewed. I don't believe this is fundamental to the technique -- rather, I think that I, with a young family and a demanding job, am just being a bit hasty.<br /><br />An inevitable question is, how strong is this stuff? Well, a 5.5" deep by 2" wide beam made from two pieces of .025" channel (top and bottom) and .016" side skins is stiffer and stronger, in the vertical direction, than a 2" diameter, .049" wall thickness CrMo round tube -- and half the weight. With no welding, gluing or composite layups. Which is why I would really like to see this construction technique scale up to a full vehicle.Ihab Awadhttp://www.blogger.com/profile/15207814198779576601noreply@blogger.com5