Unstick speed
 

What is unstick speed ?in plain language please,do we have to find it during our line operation?Thanks.:sad:

Haven't heard that term in years. It's a B-52 performance speed!

B52's don't rotate at takeoff, they unstick. It's similar to the definition of V1 speed. But it's more likely the speed at which the ass-end of the plane begins to fly.

It is at this time the airplane is capable of flight in ground effect. B52's utilize ground effect more than other airplanes I've ever flown. After unstick speed, an engine loss is handled in ground effect.

I fly my engine loss senarios exactly this way in 767s, for many reasons other than performance. But that's a whole other tread.

Do a google search of unstick and B-52s...you'll get more information.

Vmu is determined during flight testing. It is the speed at which the aircraft become airbourne at the maximum possible body angle. This is achieved when the tail is in contact with the runway. There is some great footage of 747s and 767s dragging their a@@@s on the groung with a ply-wood (Yes seriously!!) skid attached.

A useful definition of the V speeds can be found here.

From my old Douglas DC9 manual, Performance Section:

"...the minimum speed that the aircraft can be made to lift off the ground, without demonstrating hazardous characteristics, and continue the takeoff." It is established for both all-engines and one engine inoperative.

This is the pilot's answer as it is the practical definition.