Coffin Corner
Thread Starter
Joined: Apr 2008
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From: Canada
Coffin Corner
I have read with great interest the posts concerning the diminishing range of allowable speeds for a heavy airliner at higher altitudes, ie between stalling and overspeed. Is there any significant difference between say, the A 330-200 and the B767-300, in their allowable speed range at similar heavy weight and high altitude?
Thread Starter
Joined: Apr 2008
Posts: 45
Likes: 0
From: Canada
As of now, 377 viewers of this question but zero replies!
Is this because:
It was a dumb question?
The question was badly written?
To provide an answer would be too time consuming?
There is no clear answer?
Neil
Is this because:
It was a dumb question?
The question was badly written?
To provide an answer would be too time consuming?
There is no clear answer?
Neil
Joined: Jun 2004
Posts: 1,843
Likes: 0
From: Australia
There have been no replies because each aircraft is uniquely different to another. To take the point even further, the same aircraft type at differing weights exhibits entirely different characteristics as the weight varies.
Apples and Pears, Chalk and Cheese...................
Regards,
Old Smokey
Apples and Pears, Chalk and Cheese...................
Regards,
Old Smokey
Last edited by Old Smokey; 10th June 2009 at 04:13. Reason: Can't spell for nuts
Prof. Airport Engineer
Joined: Oct 2000
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From: Australia (mostly)
So this thread is not left hanging, with the scepter of the coffin corner unanswered, ELAC in R&N here said the following for the A330-200:
I don't have the same data for the 767-300.
At FL350 and 210 tons my A330-200 (slightly different engines) would have had a barberpole at M.86 of 292 KIAS and a Vls 1.3G of 241 KIAS, a spread of 51 kts. A M.80 cruise would have been at 272 KIAS and the recommended TAPS would have been 260 KIAS. At either speed there would exist an approx. 20 KIAS margin to the nearest limiting speed, let alone the nearest actual buffet speed. That's a pretty wide margin to operate within and hardly anything like a coffin corner.
Joined: Apr 2009
Posts: 13,226
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From: down south
I have just been looking at Buffet Onset Boundary charts for three different jets and, whilst they all look the same, they are not when you put some examples in.
Things such as wing section, % MAC of C of G, weight etc. all come into play. Thus the range between low and high speed stall will vary from aircraft to aircraft.
Things such as wing section, % MAC of C of G, weight etc. all come into play. Thus the range between low and high speed stall will vary from aircraft to aircraft.
