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-   -   Pilot Yak54 30cc help with getting it trimmed correctlly (https://www.rcuniverse.com/forum/questions-answers-154/11595409-pilot-yak54-30cc-help-getting-trimmed-correctlly.html)

Jetdesign 02-27-2014 07:34 PM

Note that these planes are designed for 3D flight. There is a good chance there is 0 positive incidence in the wing. It is probably a recessed wing route, too, so not much you can change without major surgery.

Check your control surfaces, make sure things are straight and properly lined up, etc. Double check your CG, then check your engine thrust.

Fly at 75% throttle in a straight line parallel to the strip and cut the power when the plane is in front of you. Does it climb, dive, or fly level and gently start to lose altitude?

ggate 02-28-2014 05:08 AM

Joe
I am going to do some checking on it tonight. A friend is bringing some incidence gauges. I will check thrust line also. If weather permits i will do some flying tomorrow..

flycatch 02-28-2014 08:56 AM

If you don't have an incidence meter get one. It can either be mechanical or digital. The next thing to do is move your question from this forum to that of "pattern" and ask the same question. You need to establish the relationship between the incidence angles of the stab and wing. After this is done than you can move on to thrust angles of the engine. If all this fails than contact the distributor of the ARF.

ggate 02-28-2014 05:13 PM

Joe
I set plane level to canopy rails.
Incidence on wing is 1/2 deg pos--up at LE
Incidence on stab is 1.9 deg pos--up at LE-I think this is where the problem lies.
what u think.

Greg

ggate 02-28-2014 05:26 PM

Ok guys
here is the deal.
I set plane level to canopy rails.
Incidence meter on wing--1/2 deg positive up on LE
Incidence meter on stab-1.9 deg positive up at LE
Have not checked thrust line yet.
Problem is stab.

AMA 74894 03-03-2014 07:05 AM

JUST to make sure we're all reading this correctly, you're saying:
the wing is 1/2 degree leading edge UP (higher than the trailing edge)
and the stab is almost two degrees (1.9) also leading edge UP (LE higher than the TE) ?

if the above is true, it does sound like the stab is at least part of the problem. did you check the firewall / engine thrustline?
that could be off too...

ggate 03-03-2014 09:04 AM

Jim
yes that is what it checked. I re-leveled plane to canopy rails- wing is near perfect to 0- stabs were almost 2 deg positive. I fixed stabs and set to 0.
flew plane this past week-end. changed cg several times. Plane flies much better. Have 2 clicks of up elevator trim. That fixed knife edge rolling to canopy. Now i am going to put 1 deg upthrust in engine. Heres why. When i flip inverted at airspeed just enough to keep it flying it holds true. Increase throttle an she starts to climb inverted. Also with a power up vertical she rolls to belly. I think about a 1 degree upthrust will get it feeling like a want.

speedracerntrixie 03-03-2014 08:50 PM

I would suggest dropping the ailerons just a bit before trying the up thrust. Adjust them about 1/16" down.


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