ORIGINAL: 5_spot
On my alpha 60 i had it all set on the ground per book instructions,but when i takes off it climbs at a fast pace,i've readjusted the elevator but it needed more so i readjusted,but it still wants to climb,i think i have turned the adjustment a full six turns and it could be more but i've trimmed the tx,i'll wait til i get some calmer winds before trying it again,all this is at full throttle.It has a 17 oz tank if it makes any difference.
The typical trainer is VERY difficult to trim so it does not climb at full throttle.
The trainer USUALLY (I have a couple of examples where this is not true...) has significant "decalage" or angle of incidence difference between the wing and the horizontal stab. That angular dfference is similar to holding a lot of up-elevator all the time. When an airplane has this decalage, increasing airspeed increases the downforce on the tailplane, and lifts the nose. The nose lifting puts the airplane nto a climb... and the climb requires more power than level flight, so maximum airspeed is somewhat limited by this part of the airframe design.
You can overcome this by shimmng the trailing edge of the wing up, thust reducing the decalage. However... its not really recommended. (by me... Others recomend it all the time as a way to improve aerobatic capability.) If you make the change... then you are sacrificeing some inherant stability for the increased airspeed and some increased aerobatic performance. (particularly inverted flight) You would also be taking out a designed airspeed limitation effect...
See my post about "GREAT BOOK" (posted today) and if you can... find a copy and read it...
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Your oversize tank will have your model a bit more noseheavy than normal when its full... requiring more up elevator for the same level flight speed, and making higher speed pitch the nose up more.
BUT its inappropriate to adjust the CG for the larger tank...
Do test-trim flights with very little fuel (3 to 4 oz at take-off) in the tank to determine how far back it is safe to move the CG. (you can almost always move it back some on a trainer vs what the instructions reccomend. AFTER you have learned a bit about controlling the model.)
Be careful about excess climb-out angle with a low fuel level... you don't want a dead-stick on take-off.
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There are all kinds of "trims" involved in an aircraft. But ALWAYS... IN FLIGHT you trim the elevator to match the desired level flight airspeed. Whether by constant pressure on the stick, or with a bendable (not adjustable in flight) trim tab or with a trim-wheel.... The elevator "trim" controls level flight airspeed. The throttle controls if you have the power to maintain that speed in level flight, or if the plane is going to climb or dive due to excess or inadequate power.
The transmtter "trims" are actually equivilent to having an adjustable spring on the control stick in the full scale aircraft... to vary the tension applied to the stick, taking a load off of the pilot's arms.