The S-70 Black Hawk has some kind of movable surfaces on its tail, look:
Source: Airliners.net
They look like "elevators" on airplanes. Does anybody know what are these things for?
$\begingroup$
$\endgroup$
3
-
1$\begingroup$ Related: Can the MH-60 helicopter fly without one or all of the stabilators? $\endgroup$– foootMay 9, 2016 at 22:27
-
$\begingroup$ Curiously, a variant of this is used for presidential transport by the Marines. $\endgroup$– Burhan KhalidMay 10, 2016 at 8:13
-
$\begingroup$ I had a pretty good idea once I looked up what an empennage is. $\endgroup$– MazuraMay 10, 2016 at 14:11
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
1
It's a stabilator used on the Blackhawk to reduce attitude changes with airspeed and to offset pitch effects from the tail rotor. It's part of the automatic flight control system.
All "traditional" design helicopters have horizontal stabilisers to push the tail down to reduce the nose down pitch in forward flight. Fixed ones are normally trimmed to provide a more level deck at typical cruise speed.
On the Blackhawk, it's fully movable. It is automatically adjusted according to collective pitch and airspeed. From here, the benefits are:
Align stabilator and main rotor downwash in low speed flight to minimize nose up attitude resulting from downwash.
Provide collective coupling to minimize pitch attitude excursions due to collective inputs from the pilot.
Decrease angle of incidence with increased airspeed to improve static stability.
Provide sideslip to pitch coupling to reduce susceptibility to gusts.
Provide pitch rate feedback to improve dynamic stability.
-
$\begingroup$ Not just on later models. It was that way on the A. $\endgroup$ Oct 13, 2016 at 18:05