Depends on the purpose and make of the helicopter.
The SUPER Cobra (two engines instead of one) is a "post" Vietnam helicopter used by the USMC because it was cheaper to buy than the newe APACHE attack helicopter.
The US Marines needed fast, armoured helicopters capable of heavy hitting.
For a fairly new helicopter, around 120 knots. Around 150 mph, except for fast military helicopters.
AH-1W Super Cobra HelicopterCost $10,700,000.00
No, a Cobra helicopter cannot break the sound barrier. The maximum speed of a Cobra helicopter is around 185-190 mph, which is significantly lower than the speed of sound (about 767 mph at sea level).
The AH-1 Cobra was first fielded in South Vietnam in 1966.
A fast aeroplane will be faster than any helicopter, but a fast helicopter can be faster than a slow aeroplane.
Military Police Battalion Cobra was created in 1978.
The fastest are attack helicopters like Apache, they mostly fly about 230 -250 mph.
a king cobra has a very fast strike
Cruising speed is about 150 mph.