Thrust angel of a pusher.

[stevem1928]

I have asked this question before, but I still seem to be a little confused. I have included a diagram to eliminate the confusion.

The plane in question is a miniature version of a Soarstar (pusher), using an IPS - A. I have not tossed it into the air yet, for fear of it crashing at high speed into the ground, due to incorrect thrust angle. While holding the plane in my hand at full throttle, the thrust appears to be forcing the nose down hard. I tried to correct it by applying more thrust like figure "A". But, it did not seem to help. Which way do I change the thrust angle if the nose wants to go down too much? A or B?

From what I have read, it is opposite of what you might first think, due to the fact that the thrust is coming from behind the CG. I also believe the fact that the thrust is above the vertical CG has some affect also.

[propfan]

B

You want the nose to go up so the tail has to go down.
The reason it's already forcing the nose down is probably that it's above the CG.

[Sparky Paul]

I think you'll find dead straight ahead or your "A" will work.
"B".. don't even think that! Serious downthrust!
This is "B"
First toss on this was a rapid pitch down onto the runway. The fortunate provision of wheels helped.
About a 3/16" shim of scrap wood under the rear of the mount fixed that problem.

[propfan]

Oops! I forgot the propeller pushes towards the motor instead of pulling away. You want the engine to push down but that is A like Sparky Paul said.

The trade off will be that while that gets the nose up, it pushes the whole plane down