I’m a novice flying a Great Planes PT-40 with an O.S. FS-52 four stroke engine that has about two hours on it, so it’s broken in. The engine quits just after finishing an aileron roll. It handles loops and stalls OK. On the ground the engine runs OK when the plane is pointed straight up and when its inverted. What could be the cause of the engine quitting after finishing an aileron roll?

Jolly the first place I would look is in the tank. It could be the klunk is against the back of the tank or the tubing to the clunk is too stiff and not letting it drop when the plane is inverted and is sucking air. Klunk could have fallen off to. Check the simple stuff first.
FB

The clunk is free - it bangs all over the place. Dubro 8 oz. tank and klunk, which is pretty heavy.

just a thought, mayb your pushrods are hitting, or mayb the reciever is causing the thotle servo to go to 0 ? just a thought.

It sounds like a plumbing problem that the roll aggravates to the point the engine is fuel deprived and it quits. As stated above I would pull the tank and start there. It's not getting fuel for some reason.

Does it happen when you roll to the right OR the left? Or do you always roll the same direction?

I'm guessing it's a fuel flow problem too, but....
Dennis-

I had this problem with a fuel line that had a big loop to the carb with a heavy fuel filter. The line was partially kinked closed, and a hard roll in one direction would close it completely.

Thanks a lot, guys. I've redone the "plumbing" and will test on Saturday. I'll keep you posted.

I don't know what kind of raduio you have but some "JR" have throttle/aileron mixing which comes with the radio already on. I have seen this happen recently. Of course if you can flt around thats probably not it but wanted to let you know it exists

I'm using a Futaba 6EXA.

I don't have the aileron problem but the loop problem,when I do a tight fast loop the engine will sputter and die unless I have it really rich..its a GMS .47,any thought to this deal?

Same deal, something in the plumbing somewhere. Switch out lines, pull tank and check in tank line, etc etc.

Andy