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

From:         weiss@watson.SEAS.UCLA.EDU (Michael Weiss)
Organization: SEASnet, University of California, Los Angeles
Date:         02 Apr 93 05:36:14 PST
References:   1 2 3
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In article <airliners.1993.282@ohare.Chicago.COM> rdd@cactus.org (Robert Dorsett) writes:
>>Anyway, one of the measures he took to get back down to the glide slope
>>was to retard the thrust levers below a recommended minimum setting. 
>A pilot can normally retard the throttles all the way back to idle
>without having to worry about the fuel controller or flaming out the engine.  
>The thrust at this setting can range from 300 lbs to 1000 lbs per engine.  

Normally, yes.  The 727 is an exception.  Evidence of that can be seen in the
angle of attack used on final.  I doubt you'll see other aircraft with such
high angles of attack on final.  The specifics behind this are unclear to me,
but I have heard exactly the same thing from an American Airlines 727 Flight
Engineer and from my girlfriend's brother, who is an airline mechanic.

>Do you have an issue date?  Again, allegations of a "deep stall" are some-
>what serious, since it suggests the airplane is in an aerodynamic condition
>it *can't* escape from.  In the case of the BAC-111, for example, aerodynamic
>effectiveness of the elevators was almost nil.  If the 727 is actually capable
>of such a stall, I'd like to hear about it! :-)

Perhaps the 727 is not, but the DC-9-80 (later renamed MD-80) got into a deep
stall during FAA cert.  The configuration of the 727 wing/tailplane is very
similar to that of the MD-80, and deep stalls are a fact of life with high
tailplane aircraft.
--
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-   Weiss   izzydp5@oac.ucla.edu  |   University of California, Los Angeles   -
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