Tiger Moth revisited - Page 3 - RC Groups
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Mar 14, 2017, 12:13 PM
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EdSoars's Avatar
Yes, it is a beautiful place to fly. This version of the TigerMoth has some real potential for offering the solution to the design goals. It's fast, aerobatic and very damage resistant.

I haven't decided yet whether the separate elevator is a good or bad thing. If I can get the crow sorted, which isn't too difficult, it might be worth the extra expense and work. I'm going to set up a separate program that has the ailerons operating as elevons, and the separate elevator engaged only for crow.

Why? Because in normal fast or cruise flying, the separate elevator works well, but when you want to slow down, it creates a washed-in condition that makes for tricky handling; just what you don't want for landing in turbulence. If you slow down with up elevator, you want the up-travel on the outer surfaces, not at the root.

Five more TigerMoths are on the bench. I have orders for two from local flying buddies, and I want more myself. It is that much fun to fly! The next generation is going to use 1/8" nylon rod on the leading edge and a stronger sub-spar in front of the trailing edge stock.

The batteries will be AA's end-to-end, to reduce frontal area. Also a hard rubber nose cone to reduce foam wrinkling in front.

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Aug 13, 2017, 09:03 AM
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EdSoars's Avatar
There should be a post-mortem for this version of the Tiger Moth. Sadly, no video. I was standing on a narrow path with the TM cruising around, when i heard a mountain biker approaching. I looked behind me to be sure my dog Joe was out of the way, and lost sight of the TM. A buddy saw roughly where it went down, and I found it, but it was pretty thoroughly smashed.

The last control setup seemed to be the best: use the outer surfaces for elevons, with the center surface for down trim and crow. At least for this fairly low aspect ratio, I never felt the need for rudder coupled to aileron: the rolls were axial and smooth. In fact, this was the easiest-handling plank I've ever flown, partly because the control throws for trim and elevator are larger than for full-span elevons; much less sensitive to a small amount of servo gear slop, easier to maintain a good trim condition.

If the dihedral is kept nearly flat on the top surface, the central control surface ("flap") can be activated by only one servo. On the next version, there is a little dihedral, which required a hingeline that starts on the top surface at the center line, and ends up on the bottom surface at the outer ends of the "flap". A bit tricky, and not as easy to achieve a zero-friction, zero slop hinge.