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:         30 Mar 93 10:04:58 PST
References:   1 2 3 4
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In article <airliners.1993.283@ohare.Chicago.COM> gbisaga@mitre.org write:
>|> The 727's spoilers can be used as speed brakes in-flight.
>I believe this is only true in the 72s if you're using flaps 1 or less,
>maybe up only.  I need to check with my 727 pilot friends to be sure.  

No, there's no restriction.

The spoiler system is comprised of a panel of seven spoilers per wing.
These are arranged in groups of four spoilers outboard and three inboard.
They are all hydraulically actuated.

The five outer spoilers are "flight spoilers."  They are used to command
maximum roll rates, when needed.  They are also user-selectable from 0 to
45 degrees (full up) via a single speed-brake lever in the cockpit.  They
can be used in any flight configuration, and often are used during initial
let-down.

The two inner spoilers are "ground spoilers."  These have a two-step actuator.
When on the ground, if the speed brake lever is selected, these will deploy
along with the flight spoilers if the Air/Ground switch is set.

Many (most?  all?) airplanes come with an automatic speed brake system.  
When placed in the ARM detent, all spoilers will automagically spring to
maximum when the A/G switch is set.  This reduces some fumbling in the
cockpit on roll-out.

You may be thinking of the leading edge devices, which are fully deployed by
flaps 5, and remain deployed until flaps-up are commanded.

Note that there's no Flaps 1 on the 727, only Flaps 2, 5, 15, 25, 30, 40.

All of the above only applies to the 727.


Sources: various technical publications.



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