Re: 727 deep stall (Re: tip vortices *do* exist!)

From:         rdd@cactus.org (Robert Dorsett)
Organization: Capital Area Central Texas UNIX Society, Austin, Tx
Date:         25 Mar 93 00:08:43 PST
References:   1 2
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In article <airliners.1993.267@ohare.Chicago.COM> you write:
>In <airliners.1993.255@ohare.Chicago.COM> jonathan@hermes.chpc.utexas.edu (Jonathan Thornburg) writes:
>
>>On this same trip, coming in to Salt Lake City over
>>the Wasatch mountains, I could clearly see the spoilers being deployed
>>several times, *without* their being any perceptable roll.  

The 727's spoilers can be used as speed brakes in-flight.


>>I believe
>>the Salt Lake City approach path is somewhat notorious for requiring
>>rapid altitude loss.  (Indeed, one of the early B-727 deep stall crashes
>>was on such an approach, I think.)
>
>Do you have a reference for this crash (how about Robert or Karl?)?
>
>I wasn't aware that any 727s had been lost to deep stall.  

There haven't.  


>I was actually
>under the impression that 727s were somewhat immune to deep stall 

They are. :-)  The horizontal stabilizer surface area is larger and the
tailplane itself is higher than the BAC-111. 


>and that
>the designers had spent considerable effort getting this T-tail bugaboo
>out.  

They did. :-)  The 727 followed the 111, and the designers were certainly
aware of the problems the 111 had.


>I've seen several videos of 727s in stall testing - seemed pretty
>straight-forward.

Very gentle.  See Paul Havis' "Test Flying and Building the Boeing 727 &
747" for some manufacturer stall footage. 




---
Robert Dorsett
rdd@cactus.org
...cs.utexas.edu!cactus.org!rdd