Another stall spin

On Tuesday, September 4, 2012 8:02:52 PM UTC-4, noel.wade wrote:
On Sep 4, 10:34*am, bumper wrote: It's easy enough to practice low (within a few wing spans), slow, high bank angle turns in a power plane like a Super Cub or Husky. Not so many opportunities in a glider. To the uninitiated, there's a tendency to skid a turn when low, as some pilots try to minimize bank angle - too much bottom rudder, not enough aileron. Not a good situation to be. Yes, one thing to point out is that a lot of training spins emphasize a lot of back-stick *plus* a punch on the rudder to initiate the spin. But IMHO this isn't how spins develop in the real world. I believe that many spins develop as the aircraft's situation degrades over a couple of seconds (airspeed bleeds off, or back-stick/rudder is slowly added in by the pilot without realizing they're "creeping" on the controls). Another item for thought: Using trim on an aircraft is great (I am constantly re-trimming my aircraft). BUT if you trim the aircraft for flight at a slow speed (say an approach-speed that's a little too slow), the trim-spring is what is "pulling back" on the stick. YOU will not feel yourself pulling on the stick. Yet the aircraft may be dangerously close to a stall/spin. And once it starts to develop you'll have to PUSH *against* the trim spring in order to un-stall the wing! Simply "relaxing the back-pressure" will not break the stall or stop the spin. This goes against a lot of the muscle-memory we learn when we train in gliders and perform training stalls & spins, so pilots are not likely (IMHO) to take the full corrective action. Lastly, think about wind gradient and headwind/tailwind components... Let's say we're making a landing pattern (and this could be particularly bad in an off-field situation). There's a tailwind on downwind so the ground rushes past and we try to slow down (perhaps subconsciously). Then we turn base/final and while we get a bit of the headwind, we also have to remember low level wind gradients mean that as we descent down close to the ground that headwind goes away. So we have pulled the stick back (from trying to "slow down" on downwind) AND we lose lift as the headwind decreases. Stall, anyone? And possibly a spin, if the wind gradient kicks in during the base-to- final turn. Think about the typical base-to-final spin accident - they tend to happen when people are low and not yet on final, right? So isn't it possible that its not just them "skidding" the turn, but also possibly aggravated by the wind gradient? How many instructors discuss the wind gradient with their students? How many discuss it in terms of a low base-to-final turn? --Noel (CFIG-in-training)

I teach the sneaky slow low banked turn with student looking into the turn(where are the "pilots" looking when they spin on base to final?) while I have them try to force "just a little more turn" while very subtly sneaking in some more inside rudder. When it goes, they are surprised. That is the point- it comes as a surprise, especially when the pilot isn't watching the attitude and yaw.
Add a bit of a gust or shear, and it is even more sudden.
Question- "how would you like to do that low?" gets the predictable answer.
UH