There is only one way to stall a wing. Force it into too high an AOA.

High speed or low speed stalls........ they happen from the elevator forcing the wing to an AOA where it stalls. If you thought your speed was good enough and the tail had come up and everything looked cool, it wasn't........ if it stalled.

Consider how heavy your Cub might have been. Heavier means you need more lift sooner.

My Phoenix SD is one of the heaviest 46 size ARFs I have. Until it's at cruise speed, it's elevator is moved very carefully.