In article , Andrew Warbrick
writes

snip

I won't let a spin demo go beyond the incipient stage
below 1500', but then, I'm a wimp.

Dear Andrew,

You are not a wimp, you are sensible and alive. And so are your
students.

Having flown many spins in a military training environment, there was
always a "golden rule" on recovery heights. Heights for spin entry and
minimum heights for recovery were always such that if recovery had not
taken place, there was sufficient height to bale out or eject as
appropriate. I speak of the fully-developed spin, of course. Bale-out
heights were, to my recollection, something like 4000 ft for a Harvard
and Jet Provost and no less than 12000 ft for a Hunter. I recall a
Hunter spin bottom out once at 6000 ft but passing 12 it was recovering
so the crew stuck with it. They started at 35k, by the way!

It is this simple safety rule that some parts of the gliding world seem
to have forgotten. An instructional cult seems to have grown up in some
places that seems to think that low level spinning is an absolute
necessity to teach student pilots of the dangers. I instructed in
gliders for 35 years and IMHO, it is not necessary. Recovery from
fully-developed spins can be taught at a safe height just as in other
branches of aviation. There is nothing "macho" about spinning too low,
just a failure to understand the dynamics of the manoeuvre and the
possible dangers not only to the instructor but to the innocent student.

In any case, the emphasis in instruction should be on quick recovery at
the wing-drop or incipient stage before the spin has developed fully.
THAT should be practised very regularly and full multi-turn spins only
rarely to show what can happen if the correct actions are not taken
early enough.

I have even heard it said by some instructors that deliberate low level
spinning is required because the student must experience the visual
"ground rush" that he/she would get in a real situation of an
inadvertent spin at low level. This is a good way to an early grave,
particularly if something happens in one of these low level spins such
as control failure, rudder cable slackness, or even as simple as
someone's foot trapped the wrong side of a rudder pedal.

Also, spins are not regular reliable manoeuvres with streamlined stable
airflow, they are complex interactions between turbulent (stalled)
airflow, significant control moments and inertia/gyroscopic effects.
Occasionally, for no particular reason other than statistics, a spin
will go deeper into the stall (high alpha) than normal, and recovery
will be delayed. Think of this before continuing a deliberate
fully-developed spin below the height above the hard stuff at which it
would be possible to bale out if the recovery were to go wrong.

There are old pilots and there are bold pilots, but there are few old,
bold, pilots. An aviation truism, I think. Me, I'm old but still here
and enjoying cross country soaring!

--
Ian Strachan