easyways1

Plane is a Pizzaz with a 46fx in the nose. Already have about 2 oz. in the nose trying to balance per instructions. On first flight I needed nearly all of down elevator trim for level flight. What gives?

shenion

Sounds tail heavy. You need down elevator to hold the heavy tail up.

cruzomatic

My Feedback: (17)

yup,,,,I agree with Henion.

Did you zero out the elevator servo?

Zero it out, set the elevator as close to neutral throw and put the horn on the servo. It helps out a lot.

easyways1

Thanks for the info guys. I guess it's "break out the lead time" . And Henion, That Kadet I came out to your field with is still flying, This Pizzaz is giving me trouble though. I've got five planes now, all different flavors, and enjoying the hobby tremendously.
Thanks again.

Curtis

ctshaynes

A tail heavy airplane will generally be overly sensitive to elevator input. (a little move of the stick causes a LOT of response from the model.)
So just because you had to trim it down doesn't nesesarily mean it's tail heavy.
Basically if it flew ok after the down trim then you're ok in the balance department. just rotate the control horn on the servo a bit so that it has the same amount of down trim you needed when the trim slider is centered, and you should be all set.
Somebody feel free correct me if I'm wrong here...

Geistware

My Feedback: (16)

I assume you landed OK, I would fly it again and roll inverted. If it wants to keep climbing then it is tail heavy.

shenion

Yes, if it flies ok then you have a reasonable balance point.

Definately at least change the linkages so all your trims are centered. Gives you full range if you need it.

I like mine a bit tail heavy. Inverted flight then needs little or no elevator input. For symmetrical wings the ideal CG will give hands off flight on both normal or inverted flight.

Tail heavy will have its effects though:
1. More sensitive to elevator input
2. Will tend to "ballon" on landing.
3. Will snap roll easier (maybe too easy!)
4. May need more rudder on turns, otherwise it may lose speed or roll under. (Tail will tend to "hang low" on turns.)
5. Will do stunts better, especially knife edge or snap rolls.
6. Will be more sensitive to wind gusts.
7. Basically a requirement for 3D.
8. Inverted flight will take less input.

Tail heavy will "wallow around" more.

The main thing is how does it fly. If it seems too sensitive then cg is too far back. If it is hard to maintain pitch on landing, the CG is too far back.

If you have a hard time in windy days, add a bit of nose weight. Can't say how many times people have complained their planes stink on windy days. I hand them one of my prop weights and they are amazed at the change.

Nose heavy:

1. Will be less sensitive to controls.
2, Will be more stable.
3. May not snap roll or do stunts well.
4. Will be stable on landings, but may not flare well. Will also land faster.
5. Inverted flight may take more input. May not even be possible if real nose heavy.
See how it flies. Play with the CG in small seps to see what is best. ALways start out at recommended setting.

A lot of trim may make it fly level, but will likely vary at speeds. It also adds some drag.