[tommy321]

Originally Posted by Trumpetman

...responding to the (IMHO) mistaken suggestion that climbing under power indicates a nose heavy condition...

OOOO an aerodynamics debate!

Actually assuming your wing and stab incidences are correct, climbing with power IS a symptom of being nose heavy - really nose heavy. If you're at the stage that you're into the Goldsmith trimming chart you're already really close to the neutral point you want and won't have this effect.

The simple way to think of it is:
Cruising at 50% power.
The nose of the plane is too heavy,
The tail needs to "push down" to lift the heavy nose
In order to provide this push, you trim the elevator up.

Now you add power,
With the increase in speed the elevator becomes more effective, so the trim you had at 50% power is now enough to raise the nose at 100% power and the plane climbs.

You can solve this problem with down thrust, but the main downside is that the effect of down thrust varies with power setting. So you can still end up with the ballooning effect when you chop the power (which could be argued is worse than ballooning when you apply power).

The reason moving the CG is better is you'll end up with a lighter plane and the end result is something that varies less with airspeed and power settings.

Obviously you don't want to go nuts with moving the CG back. No more aft than 30% MAC like Sam said. At some point (probably closer to 50% MAC) the aircraft will become unstable in pitch at which point it can become significantly less fun to fly. I was just suggesting removing the nose weight a little at a time. If it's climbing with power, he's certainly well forward to the unstable point - or there's something else wrong like Stab or wing incidence is out to lunch.

Cheers,
Tom

[machzx]

well considering i added weight this must be it
I was cautious with cg But the plane was flown before and the previous owner did not remove anything but his radio gear (he did it while i waited)
The weights i added are a stack of large fender washers on a bolts so i can remove 1/2 without it being a big deal and i will report back
We did have to add alot of up trim so what you are saying makes sense
thanks
ED

[Trumpetman]

Originally Posted by machzx

well considering i added weight this must be it
I was cautious with cg But the plane was flown before and the previous owner did not remove anything but his radio gear (he did it while i waited)
The weights i added are a stack of large fender washers on a bolts so i can remove 1/2 without it being a big deal and i will report back
We did have to add alot of up trim so what you are saying makes sense
thanks
ED

Ahh, a bit of new information! (adding a lot of up elevator trim). I am now more comfortable with Toms suggestion. I had assumed that you balanced to the indicated point on the plans but it now sounds like you are quite nose heavy! Interesting discussion.

[machzx]

well like i said earlier i hung it from the spar and added till it hung level?
me being cautious for sure

[machzx]

ever get to the field on a nice calm day and forget your wing tube

[Larry Pierce]

Hello There:

I am glad you are having fun with the Decathlon. I flew it for approx. 20 flights
no weight was added to the nose it flew perfect just the way you took it home.
Please never use down thrust, that will not cure your problem.
This Model used to familiarize my-self with a New Radio Spectrum 10-T.
Keep having fun

Larry

[machzx]

thanks Larry i am enjoying it really nice plane to fly
i will pull the rest of the weight out
flew it today and the characteristics prove that i was wrong to add weight