Another stall spin

I prefer to move the trim full forward before entering the pattern. The
back pressure required has not been a problem with the various gliders I've
flown. If I get distracted for some reason I hopefully will be flying
faster than required, rather than slower. I too find it easier to control
air speed by varying the back pressure. If the glider is trimmed for
approach speed and there is a loss of headwind due to ground friction, the
forward pressure required to maintain airspeed feels unnatural to me.

At 00:02 05 September 2012, noel.wade wrote:
On Sep 4, 10:34=A0am, bumper wrote:
It's easy enough to practice low (within a few wing spans), slow, high
ba=
nk angle turns in a power plane like a Super Cub or Husky. Not so many
oppo=
rtunities in a glider. To the uninitiated, there's a tendency to skid a
tur=
n when low, as some pilots try to minimize bank angle - too much bottom
rud=
der, 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)