jzinckgra

My Feedback: (11)

Without a pic, I'll try to describe this. I have an old GP Trainer 40 and don't ask me why I didn't notice till now, but the horizontal stab isn't level. The left side (looking from the back) is ~1/2" higher than the right side. I notice while doing loops, the plane wants to come out of the loop midway through and I have to compensate by putting in rudder. Under normal flying (takeoffs, landings, no aerobatics) the plane seems to fly fine, but I was wondering if there was a way to fix this. WOuld I have to break off the stab and re-glue? I was thinking of putting some weight on the left side of the stab and leaving it on overnight to try and see if I could "warp" it down or something, but I'm doubtful this will work.

FLYBOY

My Feedback: (11)

You would be better off to make the wing match the tail at this point. Put wood in the wing saddle to make the wing level with the horizontal stab. Then you don't do structural damage fixing it and noone will ever notice the diff. You can cut the stab off and fix it, but it isn't necessary. Just fix it by adjusting the wing.

FHHuber

The amount your talplane is off isn't much... more likely, you either are not entering the loop truely level (you have to learn what level really looks like...) or you are losing too much airspeed going up and that will have a wing starting to drop near the top of the loop. (any slower and the model would stall and 1/2 snap-roll out of the loop)

My bet is more on the airspeed.... Using a 10X6 on a .40 or a 10X7 on a .46? Try 11X4 on the 40 or 11X5 on the 46 and watch the improvement. I don't think the Tower Trainer .40 has theclearance to try a APC 12.25X3.75.. but that would be the optimum aerobatic prop for it if using a .46. (that would hover it if you were good enough on the sticks)

If you are using a 11X7 on a .46... you are loading the engine more than you should... and that will prevent you getting the proper rpm for maximum power. The Tower Trainer just won't fly 120 mph (which is where you need to be with a 11X7 on a .46) with less than a piped .61 in the nose...

Sometimes... it is as simple as changing the prop...

jzinckgra

My Feedback: (11)

Actually I am using an 10x7 on a ASP 40.

J_R

I am with FLYBOY. Get popsicle sticks, or some other hard wood sticks, and stick them under the low side of the wing and rise it. Shim it up with until the wing is right. If that resolves the problem, you can build it up later, doing a neater repair. The stab appearing 1/2 inch higher IS substantial.

Lowering the pitch of the prop will slow the plane down, and increase thrust. Going to a higher pitch will speed it up and reduce thrust.

You might take a 10x6 along, but, I suspect you diganosed the problem correctly to begin with.

FHHuber

Just for grins. try a 11X5 on that ASP .40 and see what happens. I bet you like the result.

Re-aligning the wing may help a little and certainly won't hurt... but I really think you need more PULL from the engine in the first half of the loop.

FLYBOY

My Feedback: (11)

If your tail is off 1/2 inch, changing the prop isn't going to make it loop straight. 1/2 inch is quite a bit to be off. Fix that problem first, then screw around with the prop. I run 10 x 6 props on 40s. You can run the 11s on it if you want, but don't go longer. I run 11s on my 46 engines. It won't take much to fix the wing and you will see results.

ksechler

As you apply up elevator you are also effectively adding rudder since the stab is not square.

I don't agree with fixing the problem by tilting the wing. If you do that you'll have 2 flying surfaces that aren't square instead of just one. The only true fix is to cut the stab off and put it back on right. That said, you might be better off just living with the problem and be careful not to make the same mistake on the next plane.

I have owned several planes in my time that turned better one way than the other due to alignment issues.

daveopam

My Feedback: (9)

I'm with you Fred. The prop might not be the only problem but it's one of them.

David

dicknadine

Do it correctly by cutting the stab loose and getting it Horizontal. Mickey Mouse doesn't belong in the HOBBY. dick

woodbutcher

If you aren't going to tear this apart you could straighten it out with flying wires. Since you describe it as an old trainer maybe you just want to experiment a little.
String some weedeater line all the way around and through the stab and fin. Make it fairly taught and fasten to the bottom off the fuse. You can pull them by each other and fasten with a landing gear clamp, or you get the idea. Pull the high stab side down and CA at the hole. CA at the other points. Bonus is a stronger tail group and you haven't added weight with metal rods.
Besides, weedeater line comes in those cool neon colors

ocirema

How much tilt is the vertical fin??????

p40bri

Before you shim up the wing to match the stab take this into consideration. I have an Easy Sport that had the wing uneven on its maiden flight. What a hand full!!! The plane wanted to make left turns ONLY! Even with full right trim AND Full right Aileron I barely was able to make the plane fly straight. I managed to get the plane down and adjust more ailerons. On the second flight I had the same problem. This is when I discovered I sanded too much of one side of the saddle. I shimmed the wing to match the stab and vertical fin and the plane flew perfect.

Just be prepared for an event full flight if you shim the wing.

I personally would enjoy the way it flies now and start building a second plane. It's only a short time till you’re bored of the trainer anyhow.