Thorp Air Command - T18.net

If I am reading Sunderland drawing #101L correctly the dihedral angle should be 7 degrees. Correct me if wrong. However when I bolt the 215 and 315 fittings together, I measure 4.1 degrees. Need some comments and info. from C wing builders.

Jon Sanders

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Jon P Sanders

Are the fittings bolted to the spars? How are you measuring the degrees? the spar fittings are tapered, you would have to measure it along the bolt line. I made a 7 degree angle and clamped it to the spars to maintain the 7 degrees,
Dihedral gives the plane stability and keeps the wingtip from hitting the ground when you ground loop. I would think 4 degrees would be OK but not ideal, the plane would be a little unstable, probably would fly like a RV.

Bill thank you, was hoping you would jump in on this with your no nonsense approach. No the fittings are not bolted to the spars. I had locked in on the 215 profile and ignored the 315 taper. I leveled the top of 215 in a vise then placed the smart tool on top edge of the 315. Just did it again this time I used the hole line in the 315, it came out 6.9 degrees. I like the idea of the angle jig, will use it.

Jon Sanders

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Jon P Sanders