I recently finished scratch building a Q-500 plane. I have three flights on it and I am still trying to sort out a problem I’m having. Whenever I make a left turn and start to put G the aircraft it rolls to the right. If I keep them turns big and gentle it tracks nice and straight. What could my problem be?

I built the aircraft with zero down thrust and zero right thrust. I have double checked all the measurements from the wing to the tail and everything is straight as far as I can tell. What’s next to check?

Hi!
It stalls! That's why it snaps to the right when turn left hard and pull lots of G!
Why? Because it's too heavy or you have too much elevator throw or both. Or the wing is twisted (has wash-in at the tips)!
Have you checked wing with a Robart meter so it's straight?? 0-0-0 degrees on both ,engine, stabilizer and wing is the norm on most model



airplanes.

Ok. I’ll double check the wing. Before covering it was all straight. I’m not sure the airplane is it snapping. When I roll 90° to the left and start to pull real slow and gentle it takes about half of my left aileron stick to keep the aircraft in the turn. It’s not a quick snap like I think of a Snap roll. I am not brave enough to try a right turn yet.

I guess I am stuck flying a normal traffic pattern instead of pylon turns.

Jaka54. Sweet covering. Thanks for your help.

Lateral balance. Start adding weight to the left wing tip until it stays put during a tight turn.

Hi!
Balancing the plane in lateral is a good thing to do! I mostly drill a hole in the light wing tip and glue in some lead (mostly less than 5 gram).
When you fly at full speed and make a near 90 degree hard left turn...what happens then? Does the plane track along nice and steady or ...?

Read the Peter Goldsmith article about trimming - especially where he discusses lateral balance and engine thrust. May help you sort it out.

https://www.flyinggiants.com/forums/...ad.php?t=32733

You need to check to see if you have a minimum gap on your aileron hinge lines. You might try sealing the gap. Sometimes uneven gaps will give problems in high G turns.

In particular, he advises to test for lateral balance by doing a vertical dive, and pulling sharply to level. The heavy wing will be low after you pull out to level. More details as to why that is a better test, and why it works, in the article.

Thanks everyone. I will check out the Lateral balance again. I'll also check that article and see what i can learn from that.

I will also put some gap sealing tape on the wing. and see what that does.

I have the plane trimmed out to fly like at arrow across the sky, "hands off from horizon to horizon" Pulling even into a loop the plane does more of an "barrel roll." I need to make the roll rate a little faster so I can do an up line with a roll and see that it does. I haven't tried much with the plane yet because I wanna sort out the turning problem. Anything more than 25% pull the plane rolls.

Thanks,
Brian

Hi!
How much elevator movement at the trailing edge?
I have 3-4mm up on all my Q-500 racers.

[QUOTE=jaka54;12695545]Hi!
How much elevator movement at the trailing edge?
I have 3-4mm up on all my Q-500 racers


1/4inch/6mm. Currently if I use anything more than what is need to fly a traffic pattern I have to use left a Aileron to keep it in the turn. I am guessing that’s maybe 1-2mm is what I use in the pattern. Anything more than that it rolls.

I hope to get back out with it next month and sort this out. Ready to race a couple guys in the club.

Hi!
What is the weight?
Have you checked the wing with a Robart incident meter so it isn't twisted ( has wash-out at the tips)

His opening post states that as far as he can tell everything is straight. No mention of excessive aileron trim. Washout shouldn’t be needed on a 500 sq in airplane that weighs under 4 lbs. It’s a lateral balance issue. I have yet to see on of Richard Verano’s airplanes without some weight taped to a wing tip to correct this very issue.

Check for aileron any differential

Not sure what that would do. By the time you pull through the turn the ailerons are back to nueltral or at least should be.

I experienced a sloppy linkage on one side of the servo arm , thus not allowing the aileron to fully extend / contract were the other did
This was causing a roll back / out when turning hard left , gentle turns & strait flite there was no issues it was always when pulling hard G's
A hard pull into a loop was to say the least.......very interesting @ 180 mph
With a new tight servo arm fitted and the issue was gone , so my conclusion was at high speed small play will affect plane stability

Good point, I agree that on an airplane like this ( any airplane really ) that the linkages need to be tight. Some people are shocked to learn that our models can hit 30 G without much effort.

Got back to the field today. Added $.10 to the tip and it’s a complete different plane. I’ll drill out the wing tip. Chang her coins for some lead and I’ll be all set. I will need to add just a little more than this. But I can’t believe how much weight i was off. When I double checked the balance everything was food. But I added the weight anyway. Thanks all for the help.