Montague
Posts: 4653
Joined: 4/19/2002
From: Laurel, MD,
Status: offline
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I'm not sure how many of you guys have had a look at the plane in person. Maynard brought one of the remaining planes to a club meeting here shortly after the trans-atlantic flight. (not the plane that made it, one of the backups).
One thing to note is that there were many many more than 5 built. I seem to recall the one that made it was actually #23 or something in that range (I forget the actual number, but it was much higher than "5"  . Several were lost in crashes or didn't test out well enough in flight trials around here. One is still "missing" in a swap or field around here after crashing during testing. (last I heard it was still missing, who knows, it may have turned up by now).
As I understand it, and listening to the guys on the team talk about it, the airframe design was based far more on Maynards experience than any calculations. Not that they didn't do calculations, but as I understand it, their range calcuations weren't done with forulas, they were done by putting a measured amount of fuel in a tank and using a stop watch to see how long the engine would run, and tests in the air measuring how far the plane would fly in what time and on how much fuel, etc. Very "low tech" really.
And the plane looks very low-tech in person. I'm sure you could cut down on drag quite a bit, and you could probibly build it lighter with composites. Though they did go to some pretty extreme lengths to reduce weight.
I did ask what the airfoil was, but I didn't get a chance to ask Maynard, and the person I asked didn't know, but didn't think there was a lot of time spent on picking a "perfect" airfoil at all.
Looking at the plane in person, the "coolest" part of the engineering by far is actually all the engine work. For every engine that made it in to an airframe, there were several that didn't measure up, or used for parts. It didn't help that the engine is no longer made. They really had to beat the bushes for engines for the project. The engines were also highly modified to reduce weight and mount the power takeoff to drive the generator and so on.
Luck always plays a part in these things as well. They were counting on a tail wind to make the crossing. But at first, the tail wind wasn't there. And the engine was running funny. They believe that the engine was actually set a little too lean, which may have actually helped in the end, though they don't know for sure.
So, could you do better with a high-tech approach? I think you might be able to. If you had someone who knows engines the way Maynard knows engines, and you also had a BIG stack of OS .61FS's sitting around. (or the ability to machine your own engine). After all, the fuel weighted more than anything else, and the FAI weight limit includes fuel. If you can't get an engine to run long enough on that many pounds of fuel, you aren't going to make it.
Not to downplay the low drag, of course. Just pointing out that there was a lot of other problems to deal with, and obviously a conventional balsa-ply-heatshrink covered airframe is good enough.
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Kirk Montague Adams
RCCA 560
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RE: Maynard Hill TAM 5 Aspect Ratio - 
