STEVESRCWORLD

My Feedback: (23)

I HAVE JUST FINISHED A KMP 30% EDGE AND MAIDENED IT TODAY. IT DIVES AT FULL THROTTLE AND CLIMBS AT LOW THROTTLE SETTINGS. WHICH WAY DO I NEED TO GO WITH THE ENGINE? UP THRUST OR DOWN? I HAD TO ADD UP ELEVATOR FOR IT TO FLY. THANKS

BarracudaHockey

My Feedback: (11)

You have too much down thrust.

And typing in all caps is considered shouting.

d_bodary

My Feedback: (85)

You need to add some upthrust.

STEVESRCWORLD

My Feedback: (23)

sorry for the all caps, just frustrated. i forgot to mention that when rolled inverted it actually climbs upward like your trying to pull a loop. i have never seen a plane behave this way. how much up do you think it needs?

Nam Vet

My Feedback: (15)

I would start by adding 1-2 degrees of upthrust to your engine. Also, I would check the incidence of your wing and stabilizer.
Yours,
Bob

STEVESRCWORLD

My Feedback: (23)

to be honest i don't know how to check it. i do have a meter though just never really any instruction on how to use it.

Nam Vet

My Feedback: (15)

Read the instructions on how to check the wing incidence. You need to secure the wing to the fuselage to check it. From the leading edge of the wing to the trailing edge, the wing should be level in the wing saddle (0 degrees) of the fuselage. It sounds as if you need more upthrust in your engine. Usually you can add upthrust by adding flat washers under the front of your engine where it attatches to the engine mount.
Yours,
Bob

BarracudaHockey

My Feedback: (11)

Ahh good call! I didnt think about that, he mentioned thrust angles and incidence didn't occur to me.

da Rock

Changing the engine thrust OR changing the wing's incidence both work. And some people consider that it's a tossup which one to do. But if you think about it, it's not always a tossup.

If the wing and stab are correctly aligned then changing the wing incidence is dirtying up the airplane. So you don't want to automatically shim the wing and forget it.

It's always seemed that the best first test is to the engine thrust. When you've got that sorted, then look at what elevator trim the airplane winds up with. If the airplane has then taken some elevator trim after the thrust line is sorted, consider changing the incidence to do some of the thrust adjustment.

Truth is, whether or not the thrust needed sorting, it's never a bad idea to consider dinking with the incidence to straighten out your elevator trim. But when you have discovered the need for a thrust change and the motor mount has a stack of washers under it, you've got the perfect time and reason to get rid of some of those washers if you can. And if you can, then it often winds up straightening out the elevator trim. Less washers, less elevator trim. Straighter airplanes fly better, faster, and with less drag.

DadsToysBG

My Feedback: (35)

There's one other thing that could cause this. If the plane is tail heavy every time you pull the throttle back it want's to swap ends. As you add throttle the elavator gets real touchy and that could account for the trim change. Dennis