What most models have right thrust for:
6. Side thrust: Fly away from you, into any wind and pull vertical.
... A: Model continues straight up; No adjustment.
... B: Model veers left; Add right thrust.
... C: Model veers right; Reduce right thrust
This is a very often repeated test included in flight tests for trimming model flight. It shows that for most, the thrust is a response to an aerodynamic action called p-effect. P-effect is a result of the prop pulling better on one side than the other. It happens when the airplane pitches up or down. As you see from the trimming advice above, it happens, and changing the thrust cures it.
It's funny, but there is no test for p-effect in any other direction.................... left for example, or down.