On Saturday, September 1, 2012 5:08:52 AM UTC-5, Duster wrote:
Where I disagree with "66" in the ASW-20 video

is that the pilot applied the POH-recommended spin recovery at high

altitude (according to the pilot's own words). He's in a tight turn,

near or below the slowest part of the ASI white-arc range when he

encounters a gust (increasing AOA). As the incipient phase begins and

the wing drops hard, he first rapidly moves the stick further towards

the outboard wing (opposite aileron) with no opposite rudder input.

His reflexive move is to reduce flaps to full negative (per the POH)

while still holding opp aileron.. The resulting decrease in AOA is

what presumably unstalls the wings. I think this is right. When low,

the POH recommends not reduceing flaps, but rather to carry extra

speed. Good lesson.

Ok, lets think about this. Steep turn, so possibly some top aileron prevent overbanking. Wing drops (bottom wing starting to stall?) first action is to use top aileron to stop the roll (top wing is presumably not stalled), then when the lower wing didn't come back up, recognize the departure and reduce angle of attack by first raising the flaps, then if necessary, forward stick. Recovery was too fast to allow a yaw rate to develop, so coarse use of rudder not really needed.

Not an expert on 20s, but I know my LS6 will recover by releasing back pressure. but manual also says to put flaps at 0 to prevent overspeeding in the recovery, should the departure end up in a full spin or spiral dive situation. Really, the response is the same - slight easing of the stick (probably not even visible in a video) and flaps up if the nose starts to drop much.

Of course, at low altitude, speed is life - when you are scratching out a save you absolutely cannot afford to depart or spin - and again now we are doing steep turns in tight, turbulent lift: quick, what's your stall speed at 60 degrees of bank? With half water? It's not in the POH, probably, so what speed do you use? AOA sure would be nice to have!

As far as only one wing being stalled in a spin - if one wing is still flying (below stall AOA), the other is just barely at stall AOA (due to yaw, gust, whatever) and the flying wing will roll you over until it too stalls (now you are spinning, via an over the top entry, or once the nose goes down you will accelerate until the stalled wing is under stalling AOA. If you fully stall the glider in a yaw, both wings are above stall AOA, but one will still produce more lift than the other, that is what causes the autorotation/spin.

Kirk
66