Originally Posted by
Fl1ingfrog
Darrol Stinton, ‘Flying Qualities and Flight Testing of the Aeroplane’ writes: ....
(6) PAUSE (say long enough to count one hundred-two hundred-three hundred) allowing the rudder to bite and take effect. THEN:
(7) Move stick progressively FORWARD (elevator NOSE-DOWN) until rotation stops. ......
The above is the technique applied when testing an aircraft for certification and for the most part there's little more than lip service to this published in the POH. It is a matter of required compliance on the part of the manufacturer.
Back in 1936, NACA Tech Note 555 stated:
"The recommended operation of the controls for recovery from a spin, which presupposes that the ailerons are held in neutral throughout the recovery, is as follows:
1. Briskly move the rudder to a position full against the spin.
2. After the lapse of appreciable time, say after at least one-half additional turn has been made, briskly move the elevator to approximately the full down position.
3. Hold these positions of the controls until recovery is effected."
The latest NASA advice is in their TN D-6575 which states:
"It is important to note that when these results were obtained in 1935, the airplanes of that day probably were in the zero loading condition previously discussed and today this recovery technique would apply only for airplanes that have similar loadings. As previously pointed out, the control technique required for spin recovery is primarily dictated by the mass distribution in the airplane. Therefore, for airplanes of different loading conditions, this control technique recommended in 1935 would probably not apply.
....
The mass distribution and the relative density determine the tail configuration requirements and the control technique required for recovery.
....
The rudder is generally the principal recovery control, but for positive (wingheavy) loadings or for recovery during the incipient spin, the elevator can also be an important recovery control and can reduce the rudder power requirements.
Experience has shown, however, that relying on the elevator is dangerous because it might become ineffective for fully developed spins, flat spins, or cases in which the mass distribution has been changed or the center of gravity has been moved behind the normal rearward limit because of changes in loading of the airplane due to growth or operational factors."
I won't go back to the time when Stinton wrote his book but the current FAR 23 Flight Test Guide has: "Recoveries should consist of throttle reduced to idle, ailerons neutralized, full opposite rudder, followed by forward elevator control as required to get the wing out of stall and recover to level flight. For acrobatic category spins, the manufacturer may establish additional recovery procedures, provided they show compliance for those procedures with this section."
Originally Posted by
Fl1ingfrog
I've been concerned for many years with regard to the language used, such as; "briskly", "pause" and "progressively" without any of these words being defined. Briskly could, in the heat of the moment, be applied too much and tip the aircraft inverted. A pause could be anything in a high adrenaline moment and delay the recovery too long similarly the term progressive. Stinton does offer some definitions but few manuals do so.
As you can see, NACA explained the "pause"; "briskly" is about the rate of movement not the amount (which must also be specified) so that seems clear to me; "progressively" also seems clear to me. Pilots should know enough theory to understand why those words are used - Australia's CASA has such info required in their Manual of Standards for underpinning knowledge in the spin training.