Hi All,

I have a balsa usa 90 eindecker,and was hoping someone would suggest what engine thrust angles to use in the model,it will either be a 2 stroke 61, or a 4 stroke 91,if you could help i would be most grateful,i was thinking of 2 degrees down and side?
Many thanks in advance
Mark

This may be a really dumb question, but what do the kit plans and instructions say about engine thrust settings?

Hi Jim,

well iv read instructions cover to cover,and theres no mention of any thrust lines mentioned,im thinking of adding 2 degrees in side and down,and see how that goes!!! but if anyone knows better let me know thanks!!

-*Deck,
If the plans show no thrust angles ,the firewall square to datum,leave it alone.Not nall planes have to have thrust angles.I built that plane and she's a floater,just build it exactly the way the plans show it.

I had one with a couple of different engines in it. The .91 4-stroke will be fine-sounds better. The plane needs down thrust or the trailing edge jacked up to lower the incidence or I guarantee you it will climb like mad on full power. You'll trim like heck to keep it level. When you reduce power, it will dive because of all the down trim you added. In my opinion, the plane is poorly designed from an incidence (wing and tail) and thrust line standpoint.

A buddy and I built 2 of the smaller ones and one big one. On the second small one we jacked up the TE 3/16 inch and it helped, but still climbed somewhat. The big one had a .91 4-stroke and an OS 1.08 in it. It cruises around at slow speed OK.

If I was doing another one, I would put a full symmetrical airfoil on it. Then you could set 0-0 and fly like normal. Since the original full scale had the very thin under cambered airfoil, any thick airfoil is non-scale so you may as well use a good flying one.