PPRuNe Forums - View Single Post - AF 447 Thread no. 4
View Single Post
Old 15th Jun 2011, 20:03
  #10 (permalink)  
RetiredF4
 
Join Date: Jun 2009
Location: Germany
Age: 71
Posts: 776
Received 3 Likes on 1 Post
THS effectiveness with high AOA > 60

HeavyMetallist
@RetiredF4: Your analysis of the likelihood of recovering from a fully developed stall is based on some flawed assumptions, principally that a stalled aerofoil has "stopped working". Lift coefficient doesn't just fall to zero after the stall AoA is reached, it falls gradually (and may even have a second peak that's not that far off the stall value). At 60 deg AoA you may still have a lift coefficient half the primary stall value, so a stalled HS can still be generating a lot of lift. In addition the wing pitching moment (nose down) typically increases significantly with AoA post-stall. In principle a conventional design is still recoverable, given reasonable lateral control and enough height.
It is based on my own expierience out of high performance aircraft with a big ugly stabilizer....... which we could stall at less angle than 45° AOA. Fortunately we had a big heavy cannon in the front with lots of weight and favorable cg.

So it would be kind if you could proof it with numbers for the AF 447, otherwise its just an oppinion of yourself.
RetiredF4 is offline