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Joined: 8/16/2003 From: davis,
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I thought some folks might be interested in the design and build process of our 2003 SAE Aerodesign heavy lift airplane for the unlimited class. This airplane was designed and built last year by 5 undergraduate students led by one graduate student (me, heh heh). The airplane was designed and built in 5 months. Total cost was around $6000.00. Here's the specs:
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Joined: 8/16/2003 From: davis,
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fuselage plug construction photos. The foam is 2.2 lb large cell extruded polystyrene. Full size templates were printed on the pen plotter and glued to cardboard. Copper foil tape was added to the edges and the foam was hot wired to rectangular section. A steel tube was inserted into the foam centerline before hot wiring. The foam was hand shaped, fiberglassed and then lots of bondo. This was at least a two month process working about 4 hours a day.
< Message edited by aeroanalysis -- 1/11/2004 1:16:19 AM >
Posts: 101
Joined: 8/16/2003 From: davis,
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quote:
ORIGINAL: Tall Paul
There appears to be a Drela influence...
Paul, absolutely. The horizontal stabilizer is a Drela copy. It's an elegent design and hard to improve upon. Incidently, I worked with Drela on some projects when he was consulting for Scaled Composites.
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Here's the plug getting close to final shape. The vertical stab is on and the wing root fairings are being installed with a fixture to get the allignment right. Note the huge stack of blue foam in the background for the wing cores. That's $500.00 worth of foam!
< Message edited by aeroanalysis -- 1/11/2004 1:20:55 AM >
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Joined: 8/16/2003 From: davis,
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Here's the very talented Paul Roysdon (the machine) working on the fuselage plug. Second pic is the almost finished plug undergoing wet sanding. The big dimple in the nose is so the engine cylinder head isn't completely buried in the fuselage.
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The wing foam, with the talented Pierre-Luc from France. Next pic is a wing core being hot wired. Nothing new here, Feather cut on CNC formica templates. Templates were bolted to the table using steel fixtures. Original templates were 1/8" aluminum and that didn't work at all. The aluminum conducted heat away from the wire and it wouldn't cut near the template. What a bummer to have to re-macnine those templates!
< Message edited by aeroanalysis -- 1/11/2004 1:37:18 AM >
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Joined: 8/16/2003 From: davis,
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Here's the spar caps being assembled. Spar caps were Graphlite, 1"x1/4" at the root and tapering out to the tip. Way overbuilt! Spars were assempbled with Rohacell core and wrapped with carbon on the bias. This years airplane will use a mere fraction of this material. (By the way, last years airplane had an empty weight of 40 lbs, this years plane has to weight 12 lbs due to a change in the rules. Think about that, a 24 foot wingspan airplane with an empty weight of 12 lbs! It's gonna be fragile!) The second photo is the wing joiner being layed up. Solid 50k carbon tow hand layed up in an aluminum tool. Wing joiner weight was 1.5 lbs!
< Message edited by aeroanalysis -- 1/11/2004 1:46:55 AM >
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Joined: 8/16/2003 From: davis,
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Here's some of the gearbox parts. These were CNC machined on a 3-axis (very finicky) Bridgeport. The gearbox used steel spur gears inside a case. The case bolted to an aluminum ring that was bonded to the forward bulkhead and the engine mount hung off the back of that. Exactly like the typical electric airplane set-up. A custom machined aluminum engine mount was made to get the rigidity we needed. Two gearboxes were made, a proof of concept and a final competition unit. I'll try to dig up the CAD drawings for the gearbox, they are nice. The second photo shows Nghiem trying to start the engine and gearbox assembly the morning before we left for the competition. The problem turned out to be the fuel pump, but we were pretty nervous! Nghiem did all of the detail design and machining of the gearbox and is one of the most talented undergraduate engineers I have ever had the pleasure to work with. The third photo shows the engine and gearbox mounted in the airplane. Now you can see why the dimple is there.
< Message edited by aeroanalysis -- 1/11/2004 2:01:49 AM >
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Joined: 8/16/2003 From: davis,
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Here's the airplane assembled for the first time. That's a lot of carbon, folks! Message to other AeroDesign groups, don't finish your airplane the night before the competition!
< Message edited by aeroanalysis -- 1/11/2004 2:08:25 AM >
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Joined: 8/16/2003 From: davis,
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Okay, here's the team on the motel lawn putting the last touches to the airplane. That's a 35 lb steel plate being fitted into the cargo bay. Most of these folks are on night number four with no sleep. Fun stuff!
< Message edited by aeroanalysis -- 1/11/2004 2:11:40 AM >
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Joined: 12/29/2001 From: Sacramento, CA, USA Status: offline
Cool! How'd your team do last year? Do you still have the plane, where do you fly it. When does this year's model need to be ready for competition. Is there a web site with rules and info that might answer my questions as well as provide additional details about this event.
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UC Davis SAE Aerodesign Unlimited Details - 
