OCCWMF
20th Sep 2007, 12:51
On a flight test schedule I note the requirement for a military fast-jet to perform maneouvres described as WUT (maintaining max alpha and bleeding speed) and SHSS (left and right maintaining max Beta for 5 secs). Can anyone shed any light?
Knight Paladin
20th Sep 2007, 19:16
I suspect - Wind Up Turn and Steady Heading SideSlip. Hopefully someone with more than my (very limited) knowledge of flight test will be along soon to confirm or deny that!
Mad (Flt) Scientist
21st Sep 2007, 19:02
Yep, that's what WUT and SHSS mean.
I'm having a little difficulty reconciling my understanding of a WUT with what is described - when I was involved in aircraft that could (legally) perform a WUT, we did it by holding constant speed and slowly increasing 'g' and bank in a coordinated fashion, thus "winding up" or tightening the turn.
What is described (bleeding speed at max AoA) would seem to me to actually "unwind" the turn and the 'g' would decrease with speed, unless the max AoA was increasing quick markedly. It's closer to what I'd call a "turning stall" (such as the civil cert 1.5'g', 2 or 3 kt/sec decel manoeuvre) than a WUT. The fact that you're doing it at "max AoA" makes me thing its a FBW aircraft with envelope protection, where of course some of the traditional stall test methodology isn't applicable.
Other than the 5 second thing - which is pretty much an arbitrary test technique number - the SHSS sounds normal.