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Old 27th Nov 2018, 10:35
  #13 (permalink)  
JohnDixson
 
Join Date: Mar 2007
Location: Hobe Sound, Florida
Posts: 950
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212 is correct ( as usual ). It winds up being a dive. Set max power in level flight then push the nose over and fly to the desired speed, take data and then recover back to whatever comes next on the flight test card for that flight. 76 was 185 and 92 was somewhere in that ballpark-just don’t recall the number.

Military qual ( US ) is a bit different. Typically the Vne is selected as a percentage of the design weight Vh ( level flight max speed at design gross weight ), and thus it too, is a dive point ( thus similar in thinking to the 1.11 FAA point ). The difference is that the military qual requires maneuver data at that point, to include a pullout. Thus the UH-60 at design weight did 2.8 G at 193 KIAS, as well as a maneuver called a “ Dynamic Yaw “, which is described as follows: set up the Vne ( sometimes referred to as Vdive ) then apply pedal in one direction to the max steady state sideslip angle, and upon reaching that, apply full pedal at max rate in the opposite direction to achieve the transient overswing sideslip angle*. Those two numbers for the UH-60 were 15 and 30 degrees. If you ever noticed the small bayonet type device on the leading edge of the 60 door, about half-way up the window, it is there because when we did this maneuver to get the left overswing angle data point, the left door would pop open with a very loud bang, and accompanying air racket, and the pilot sitting in that seat didn’t much care for it.
*obviously this requires some judicious buildup, so this maneuver ( to be accomplished separately in both directions ) winds up being done a couple of times.

Last edited by JohnDixson; 27th Nov 2018 at 10:43. Reason: typo
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