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Old 25th May 2012, 21:12
  #940 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 76
Posts: 2,484
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Hello Dozy;
Re, "Quoting Owain Glyndwr:
It might not be so bad if it were not for the fact that your illustration
isn't actually representative of a modern airliner stall except at low Mach
numbers and with flaps and slats deflected.
Quoting Dozywannabe:
"I did say it was a generic example from basic classroom material! If not
being representative of a jet transport is a problem I'll remove it."
I might be able to provide some input here, if only obliquely to your point.

I support the views that Owain is offering; - your example isn't representative of a jet transport and isn't even generic, basic classroom material for airline pilots.

Machinbird began a very helpful diversion in the thread by opening the discussion about stall AoA's.

You may recall that in the second AF447 thread, entitled, "AF447 - Search to Resume" (you can use mm43's excellent search tool, here), Machinbird HN39, Chris Scott, mm43, ChristiaanJ, fdr, Gretchenfrage, CONF iture and others had a lengthy discussion on the stall, AoA's, FPA's/Pitch and so on. I think that discussion is well worth reviewing.

In response to Machinbird, I introduced what I thought was "standard, basic knowledge" of stall AoAs as presented in Davies' Handling the Big Jets, I discovered that my understanding of stall AoAs at high Mach Numbers and at our typical cruise altitudes was incorrect, I offered that they were around "14 - 18deg" which was what all the graphics in Davies' book indicated. They were correct, but were for the approach phase where high-lift devices were in use. AoA's as low as "5deg" had never occurred to me, and I can tell you, this was never taught or discussed in any groundschool or recurrent simulator training I had ever received - another issue.

So a very helpful discussion and exchange with HN39 began and it changed my understanding of high altitude, swept-wing, high-Mach Number flight in transport category aircraft.

It was, I think, a re-interpretation of what we might understand in old-fashioned terms as "coffin-corner", (which, for practical reasons, does not exist for the A330).

I hope this pointer to some of our previous discussions before the crash site was discovered, is both interesting and useful. I found it refreshing to re-read many of the thoughtful contributions of the time. I think it is a good thing to do so as it lends an ongoing check on one's thoughts, as well as providing some perspective to current discussions.

Happy reading!

Cheers,

PJ2

Last edited by PJ2; 25th May 2012 at 21:28.
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