View Full Version : Minimum Unstick tests
1.86EPR
13th Jan 2002, 16:52
During the flight testing of large aircraft (i.e. 777) to assess the min. unstick speed,(i) is it necessary to scrape the tail?, and (ii)if in service Min unstick speed was used, will the tail scrape?
FAR 25-107(d)
Minimum Unstick Speed, VMU shall be the speed at which the airplane can be made to lift off the ground and to continue the takeoff without displaying any hazardous characteristics
I would say that this means you aren't supposed to strike the tail, therefore the wooden buffer is there for when things dont go according to plan.
Anyone else?
Mutt.
Genghis the Engineer
13th Jan 2002, 21:55
No, definitely not a tail scrape.
The speed will have been worked out between aerodynamics and flight test departments, to give a small but acceptable margin before a tailscrape. If you get a scrape, you over-rotated.
G