VA-111 Shkval
VA-111 Shkval is a very fast torpedo. Its speed far exceeds that of any standard torpedo currently fielded by NATO. This speed is a result of supercavitation: the torpedo is, in effect, flying in a gas bubble created by outward deflection of water by its specially shaped nose cone and the expansion of gases from its engine. By keeping water from coming into contact with the surface of the body of the torpedo, drag is significantly reduced, allowing extremely high speeds.