Tweaking my first design.

[bbaker]

I recently designed and built an electric stick type plane. I am new to flying and have a couple questions about some quirks it seems to have.

It is 3-channel, throttle, rudder, elevator. The plane has a v-tail with the tail surfaces at a 90 degree angle to each other. The wing and tail are mounted more or less parallel to thrust. The wing is on pylons and is about 1 inch above the fuse. It is using a GWS 300 and gearbox. The motor is above the stick, putting the thrust line through the wing... sorta. It just seems to fly better this way.

I noticed that when yawing/rolling with rudders... if I turn left, the nose rises, if I turn right the nose drops... a lot. Is this gyro precession? Maybe fat thumbs that aren't truly moving the stick right and left? :)

And second, throttling up just a little causes the nose to rise a bunch. This is much more noticable when the motor and propshaft are below the stick and further from the wing. I read that perhaps this is happening because my thrustline is lower then my center of drag.

Are these normal things that high-wing aircraft pilots just know and deal with? I've read up on gyro precession (www.av8n.com/how) and I think it explains my turning quirk.

Would down-thrust or changing wing incidence help correct either of these?

[BMatthews]

More likely something is wrong with the mix ratio if it's consistent and highly noticable. Either that or the V angles are not even. A lean of the V to either side would produce this sort of effect.

[bbaker]

Kinda. I mentioned it was scratch built right? The wing wasn't quite level. Shimming up the left side of the wing fixed it. This brought the wing in line with the V-tail.

Pitch - throttle coupling was fixed with some downthrust.

[BMatthews]

For your pitching problem you can move the CG back a little and re-trim the elevator. As long as it still shows some signs of recovering from a stall it's all good and you can keep moving it back a little at a time and re-trimming until the stall recovery becomes very slow and long. That's about your best trim point and will set the model up to be the most efficient at flying. As you retrim in this manner you can remove some of the downthrust and set it so that the power on to power off shift is minor. A little nose up with power is actually nice but you don't want it to come up so hard that it is uncomfortable to the pilot.