As others have said, yes there is compensation but it's done with blade pitch rather than speed.

Planes do this too when they drop a payload, especially wing mounted loads. The pilot will select what to fire with consideration to weight and balance. Some fancy planes like the B1 will actually adjust the CG ahead of a scheduled drop. The A-10 will decelerate slightly when firing the GAU because there's so much mass being shot out at such a high rate.

Physics always apply, the pilot (or plane) must oblige.