I've never heard it about a helicopter......and I'm rated. But I suppose it
could be since everything is weird about helicopter aerodynamics.

"Coffin corner" refers to the narrow band of airspeed between stall and mach
buffet in a jet.

The corporate jet most affected is the older Lear Jet. The problem comes at
high altitude and encountering wind shear. If you lower the nose just
slightly the airplane goes into mach buffet. If the nose is raised slightly
it stalls. Neither is good. In a Lear the only option, if it gets severe, is
to lower the landing gear.

In the early days of the Lear, pilots would sometimes pull the mach buffet
warning horn circuit breaker. Several airplanes were lost due to upset.

Karl
ATP
BE30 LRJet CE500 DA50


"mike regish" wrote in message
...
I've only heard of the "coffin corner" in reference to helicopter flight.

mike

"Mxsmanic" wrote in message
...

By envelope I mean the area of safety between two extremes, e.g., the
"coffin corner" of some aircraft represents a very tiny envelope,
since more than a slight movement in any direction may result in
irrecoverable instability.