Stick Position at Stall
Colleagues,
I see that the "Stick Position at Stall" discussions have migrated to this thread after the Tiger thread was closed.
Some of the fallacious advice on "stick position at the stall" being given in this and other thread concerns me and needs a rejoinder, if not a complete rebuttal.
First of all we need to agree that what is being talked about is fore and aft Control Column (CC) position. i.e. elevator position, as determined by fore and aft CC position in the cockpit.
Fore and aft CC ("Stick") position may sometimes be useful as a cue to the approaching stall – but no more than a cue. As a cue this is exactly the same as IAS, airflow noise, ineffective (“sloppy”) controls, high nose attitude (and all the other “cues” that are taught in basic stalling exercises). It is just that - a cue - and is not always valid.
The fore and aft CC position at stall will vary with C of G, acceleration and deceleration rates, flap position, thrust (power) and, in some aircraft, trim position.
In a pure aerobatic aircraft, where aeros are usually performed at a (more or less) fixed fuel load with a given pilot (weight) and no baggage / freight (fixed C of G), clean aircraft and a set trim position (not normal to trim into aerobatic manoeuvres) the “fixed stall stick position” cue may be valid. However, for many other cases that are experienced every day in GA (for example, even a simple C172 with 1 POB versus 3 – 4 POB) the premise is not valid and, if taken as gospel, can be dangerously misleading.
It is just as incorrect to say that an aircraft will always stall at the "same stick position" as it is to say it will always stall at the same IAS. Both are true for any given, fixed set of variables. Change the variables and both are quite wrong.
Fore and aft CC ("Stick") position is just a cue and to be taught as an absolute is simply wrong and potentially dangerous.
By the way, a comment or two on the subject of spin recovery that has also surfaced in this thread. Roundsounds' post has touched on it. In my humble opinion, one of the biggest issues in aircraft that have a reputation for "spin accidents" (the Chipmunk being an example) is the fact that during a classic recovery drill, after the full anti - spin rudder is applied, as the CC is moved forward, the spin rotation rate increases. This leads the uninformed to react by either moving the CC back - or at least to stop moving it forward. In the Tiger, Chipmunk, Winjeel, CT4, Bulldog, Tutor, Stearman, Firefly and a range of other "classic" ex - mil training aircraft, failure to continue to move the CC forward "until the spin stops" is very likely to result in a high - rotational spin with delayed subsequent recovery and significantly increased rate of height loss. A problem exists where a pilot has been "taught" spin recovery in a more benign aircraft type, where simply releasing the back pressure or moving the CC forward a little will bring about recovery. Having been involved in high - rotational spinning trials, I will say that continuing to move the CC forward - sometimes to the stop - and sitting there, is quite counter - intuitive but, the placard shown on the Chippie's instrument panel says it all.
Fly Safe PJ
Last edited by Propjet88; 5th Jan 2016 at 10:55.