"Dave Martin" wrote in message
...

The exercise I described is one of the BGA stall reinforcement
exercises. The common cause following a winch launch
failure, pushing hard forward, then as the attitude
looks correct and as the glider is in a reduced G situation
starting a turn. (Without getting the books out that
is as simple as I can describe it) This has caused
several accidents in the UK some of them fatal.

The danger also exists when pulling up sharply in to
a thermal and pushing over hard at the top of the pull
up then starting a turn in reduced G.

Fingers crossed as yet I have never entered a spin
pulling up into thermals. But as an instructor at
a winch launch site, it something you need to be able
to demonstrate.

But we are getting away from the thread...........

Regards


Dave

These are fun maneuvers. I find a Blanik L-23 to be a prefect trainer for
them - it spins easily, recovers easily with little altitude loss or
airspeed gain.

My winch stall maneuver is done at a safe altitude (of course). First, I
ask the student to dive then zoom up at 45 - 50 degrees, then when the
airspeed drops to about 55Kts, I yell "wire break" and expect the student to
push over smartly in a simulated wire break recovery. (This gets the
student used to the attitude and feel of a wire break and the control inputs
needed for a recovery before trying it for real on the winch.)

If the student doesn't screw it up on his own, I will demonstrate a botched
recovery by doing nothing until the nose falls on its own then stopping the
pitch-down at the normal gliding attitude. This results in the airspeed at
about 15 knots with the glider held level with near full-up elevator. The
L-23 will usually oblige with a quick flip into a spin even if no turn is
attempted - try a turn and it will spin for sure. No student observing this
has failed to appreciate that the wings should be level and the nose needs
to be well below the normal glide attitude and held there until a safe
airspeed is achieved.

The thermal entry stall/spin only requires that the pilot hold into-the-turn
rudder a second or two longer than needed while trying to reduce airspeed
still further. In most cases, this is a full cross-controlled accelerated
stall from a 45 degree bank - wheee! (I've caught some high time pilots
with this one.)

Bill Daniels