Hi,
I just completed my AW 25 % Edge 540 about 2 months back. I flew the plane for triming and engine running in. I found on ful power the plane picks up a lot of hight. Can I know what cold be the possible reason for this?

Regards

Sharad

I would first check for proper engine thrust line. If it's set up with a positive incidence, it will cause the plane to climb more as you increase the rpm's. If the engine incidence is OK, then go for the wing incidence.

it should be 2 degrees (i think)

The incidence and the thrust line from the side view is at 0 degrees as per the plans. Now what should I do, time I set the wing incidence I leveled the fuselage with help of Robart Incidence meter. Keeping it in between the F1 and F 2 former.

Now what exactlly should be the problem the thrust of the engine or the incidence?......

Also like to no let say its a Incidence problem and I give a 1 degree down thrust on the engine, will it be right to do? Kindly let me know how to solve the problem.

If the incidence is 0 at the engine, wing and stab, I'd shim the engine to produce 1-2 deg down thrust. Fly it and see how it behaves. You should notice less climbing as you increase throttle. It may also have a tendency to stay on the ground a little longer during take-off.

Any airplane will climb with throttle increase and the opposite with throttle decrease... Trim your airplane at the mean speed you plan to fly...

Sharad, I'm not sure I understand the situation, but IMHO;

Nearly any plane trimmed for level flight at a constant powersetting, let's say at half throttle, will begin to climb following an increase in power, as the trimmed condition attempts to maintain the trimmed lift condition, and hence, the airspeed at which it had neutral. It will also descend when power is reduced, for the same reason. One trim setting will not maintain neutral at all airspeeds. I generally trim for a 'cruise' power setting, ie. the one which I expect to have most of the flight, and hold forward or back stick as required when flying faster or slower during manuevers. Depending on the model I'm flying I may re-trim to neutral for landing approach speed, but usually not.

A need for changing thrust angle can be determined by establishing trimmed level at less than full throttle. If the aircraft pitches up when throttle is quickly raised to full, this can indicate a need to add some down thrust. Conversely, from the same trimmed condition, if quickly reducing the throttle to low causes the nose to pitch down suddenly then some up thrust may be needed. Using the same rapid increase or decrease of throttle, and noticing if the nose pulls left or right, can else help identify a need to adjust thrust angle left or right.

I'm not sure, but I believe that a wing or stabilizer incidence problem is indicated when the plane wants to pitch up or down (not necessarily climb or descend) with changes in airspeed. Perhaps someone more knowlegeable than I am can explain this.

Thanks for the reply. After the suggestion on the forum I gave some down thrust over the engine and felt on the take of a need of some up elevator as it was dipping a bit. I guess since its my first Gaint scale and the first fully made up kit I will test fly it few more weeks and with a experinced aerobat to perfect trim and setup my plane.

The Incidence is surely a problem, I am sure as visualy looking at the fuse it is not really perfectlly leveled where the wing incidence is 0 degrees. So let see.

Hi!
Every modelairplane should be trimmed at full power...that's a good rule to follow.
If the airplane climbs at full speed then do something about it!
The first thing to do is to check the elevator setting , second: measure the wing, stab and the engine thrustline with a Robart incident meter.
On most airplanes which are lowwinged and midwinged the incident should be 0 degrees on all these 3 positions.


Regards!
Jan K
Sweden

I disagree that a plane should be trimmed at full power unless you are planning to race it... Let me explain this: If you fly at full throttle throughout the flight then by all means trim it at full bore... If you mostly fly at 1/2 or 3/4 like a aerobatic plane then trim it between 1/2 and 3/4 throttle... Full scale planes from a cessna all the way up to a jetliner constantly retrim their plane for climbing after a take off, cruising, descent, approach... Changes in weather i/e temp, density can change your trim setting for level flight from day to day or region to region... For a model it is a little but of a pain in the butt to retrim throughout the flight so find a trim setting that is close for all power settings and you will need only a click or 2 on any given flight... As I stated before:

"Any airplane will climb with throttle increase and the opposite with throttle decrease... Trim your airplane at the mean speed you plan to fly... "

If you find that your plane climbs tremendously then you may have a thrust line problem... Roll inverted and see what happens... A thrust line problem can be fixed at the field with some washers under certain bolts between the engine mount and the firewall...

Check the location of the cg. A airplane with a more forward cg will pitch up sharply with addition of power as it tries hard to maintain trim speed. With the cg located more aft, it will pitch up less sharply with addition of power. In either case it will gain altitude with addition of power unless it is trimmed for the higher speed.