I just want to say I have 100s of flights on this viper jet. It does not have a high speed stall unless you really crank hard on the elevator and there would never be a reason to do that unless you dont know how to fly jets.

However, it does have a nasty low speed stall. If in a turn, it will snap on you if you slow it down.

This is a good trainer jet. Not a wannabee trainer jet like a boomerang. it flies like a jet. Stalls like a jet. You have to manage energy like a jet. Its stall speed is quite forgiving though.

If you stalled/snapped out either you freaked out and cranked the elevator and ANYTHING would have crashed, or you were just going too slow.

Also check elevator travel, you may have too much. Fly on low rates so you can crank the elevator and it wont snap. I can check my travel if you want. You want wide sweeping turns not tight turns on the viper. If it were a delta wing of some sort then you can get away with it if you know what your doing but not with a swept wing.