Flat Spin

I'm surprised this spin thread hasn't produced more discussion of the flat
spin. One poster told us about getting into a flat spin after several
revolutions of a "normal" spin" at Minden when the Puch went flat (nose on
horizon). The poster thought it was kind of thrilling, until he applied spin
recovery controls (opposite rudder & forward stick) The Puch continued to flat
spin for another 5 or 6 revolutions. This spin started at 12,000 feet. Had it
been initiated at a much lower altitude, we might be investigating yet another
Puch-in. Has anyone else had the Puch go into a flat spin?

Perhaps those who have are no longer with us?
JJ Sinclair

I wonder where the CG was for the "Puch Flat Spin"

BT

"JJ Sinclair" wrote in message
...
I'm surprised this spin thread hasn't produced more discussion of the flat
spin. One poster told us about getting into a flat spin after several
revolutions of a "normal" spin" at Minden when the Puch went flat (nose on
horizon). The poster thought it was kind of thrilling, until he applied
spin
recovery controls (opposite rudder & forward stick) The Puch continued to
flat
spin for another 5 or 6 revolutions. This spin started at 12,000 feet. Had
it
been initiated at a much lower altitude, we might be investigating yet
another
Puch-in. Has anyone else had the Puch go into a flat spin?

Perhaps those who have are no longer with us?
JJ Sinclair

(JJ Sinclair) wrote in message ...
I'm surprised this spin thread hasn't produced more discussion of the flat
spin. One poster told us about getting into a flat spin after several
revolutions of a "normal" spin" at Minden when the Puch went flat (nose on
horizon). The poster thought it was kind of thrilling, until he applied spin
recovery controls (opposite rudder & forward stick) The Puch continued to flat
spin for another 5 or 6 revolutions. This spin started at 12,000 feet. Had it
been initiated at a much lower altitude, we might be investigating yet another
Puch-in. Has anyone else had the Puch go into a flat spin?

Perhaps those who have are no longer with us?
JJ Sinclair



Group,

As a Pitts owner and pilot who flies a LOT of aerobatics I thought I
would chime in on a possible reason for the Puchs' delayed recovery
from the flat spin.

The quickest and most assured method of exiting a flat spin is to
first convert it to a conventional spin and then exit that spin mode.

In a Pitts you get the spin to go flat by adding opposite aileron.
Take away the the opposite aileron and it returns to a conventional
spin. The puch most likely flatens out the same way.

More than one Pitts pilot has pounded in while trying to exit a flat
spin before first converting it to a conventional spin. This delay in
recovery from a flat spin could find you establishing a new bottom to
the aerobatic box.

It is therefore imperative to not add opposite aileron while spinning
(in an attempt to pick up the low wing) or risk having it go flat. If
you do find yourself in a developed flat spin you need to confirm that
you have not added opposite aileron and/or add a little pro-spin
aileron to assist in returning the aircraft to a conventional spin and
then recover from that spin mode.

All that said, I must also add that I have never flown the Puch. All
the above is based on aerobatics in a Pitts. I am not a CFIG or the
current world aerobatic champ. This is information that my CFIG has
instilled in me and is supported by many books on aerobatics that I
have read. It has also been proven to myself time and time again in
practical application.

Anybody up for a discussion on inverted accelerated flat spins?!

Gus Rasch
Pitts S1S
N21JF

"The Puch continued to flat
spin for another 5 or 6 revolutions. This spin started at 12,000 feet. =
Had it
been initiated at a much lower altitude, we might be investigating yet =
another
Puch-in."
Rather unlkely scenario as you are not taking account of air =
density/Reynolds number.
My experience of extensive spinning in the SZD30 Puchacz is that at =
altitudes in excess of 8,000 feet the spin recovery is prolonged =
regardless of spin characteristics. If "out spin" aileron is applied the =
spin tends to go flat and the rotation apparently decreases. If "in =
spin" aileron is applied the spin goes nose down and appears to increase =
in rate of rotation. Standard recovery action results in both types of =
spin stopping after three to 5 turns - remember that part of the =
recovery procedure is "centralise ailerons".
Below 5,000 feet the SZD30 tends to cease spinning if the back pressure =
on the stick is simply relaxed, i.e. without application of out spin =
rudder.
The difference is nothing to do with C of G position or aircraft =
configuration - it is simple aerodynamics connected to the air density =
decreasing with increasing altitude.=20
When considering the various reports of spinning on this forum how many =
actually take into consideration the altitude at which the exercise was =
undertaken.
Admittedly this does not explain the high?? accident rate but there is =
currently a lack of suitable training gliders in which to undertake spin =
training. The ASK21 has been designed as supposedly unspinnable - try it =
at 10,000 feet - you might be surprised. As said elsewhere how does the =
accident rate in the Puchacz compare to say the Bocian which was another =
excellent aircraft for spin recovery training. The DG505 is one of the =
newer German aircraft that also exhibits good characteristics for spin =
training although be aware of spinning close to the aft C of G.
I have to admit to deliberately spinnIng any aircraft (subject to its =
Cof A limitations) so that I am thoroughly aware of any peculiarites in =
respect of its handling. I would be amiss in not doing so as I would =
then be unable to thoroughly brief any pupils for their first flight in =
these aircraft. I also want to know what the characteristics of the =
aircraft are from a self preservation aspect - at least I will not be =
caught out by inadvertant departure from normal flight due to gusts, =
rotor, etc.

I haven't flown a puch, but I have been in a flat spin
in an SF34 with an instructor some years ago. The instructor
had decided to see how many turns we could manage in
a spin (note that after 3 you become a test pilot).
We were at 6500ft when we entered the spin. After 10
turns he decided to recover, but the spin was already
completely flat, with the nose gently nodding above
and below the horizon as we turned. Upon application
of the recovery control inputs, the spin continued
for another 3 turns (which gave plenty of time to start
worrying and thinking about the parachute) before we
eventually recovered. Unfortunately I never noted down
accurate start and finish heights in my log book, but
I think that we recovered at about 3500'. Needless
to say we never tried that again, and I wouldn't recommend
anyone prolonging a spin beyond 3 turns.

... and then you wonder why the back end fell off that
particular glider!


At 11:18 06 February 2004, Jon Meyer wrote:
I haven't flown a puch, but I have been in a flat spin
in an SF34 with an instructor some years ago. The instructor
had decided to see how many turns we could manage in
a spin (note that after 3 you become a test pilot).
We were at 6500ft when we entered the spin. After 10
turns he decided to recover, but the spin was already
completely flat, with the nose gently nodding above
and below the horizon as we turned. Upon application
of the recovery control inputs, the spin continued
for another 3 turns (which gave plenty of time to start
worrying and thinking about the parachute) before we
eventually recovered. Unfortunately I never noted down
accurate start and finish heights in my log book, but
I think that we recovered at about 3500'. Needless
to say we never tried that again, and I wouldn't recommend
anyone prolonging a spin beyond 3 turns.

Jon Meyer wrote:

had decided to see how many turns we could manage in
a spin (note that after 3 you become a test pilot).

JAR requires 5 turns.


JAR 22.221

(b) The sailplane must be able to recover
from spins of at least five turns or such lesser
number at which the spin changes into a spiral
dive, by applying the controls in a manner
normal for recovery ...

etc.


Stefan

At 14:48 06 February 2004, Jon Meyer wrote:
French engineering at its best!

That would be 'Scheibe' , makers of 'Le Moteur Falke'
?

:-)

Jon Meyer wrote:
The thought had occured to me Kevin, but I suspect
that a flat spin puts very little strain on the airframe
compared with other manouvres.....provided it doesnt
continue all the way to ground level that is.

I think that thing was just never glued together properly
at the back end, considering the fact that after the
accident you mention, they found that none of the frames
in the tail section were bonded to the fuselage skins.
French engineering at its best!
Considering the way that thing was built I think all
of us who flew it should just be glad that it didnt
break when we were flying it and that, when it did
break, nobody was hurt.

By the way, could you explain us what French engeneering has to do with the
Puch or the SF34 ? I have seen particularly badly engeneered French gliders,
notably the Bijave and the Javelot, but here i am really wondering about
what glider you are speaking. Incidentally we have heard recently discussions
about poorly glued wings from the most prestigious German factory, while
this did not occur, up to my knowledge, with the *much* cheaper Pegase.






--
Michel Talon

Sorry my mistake, got confused by the fact that the
Alliance 34 is made by Pegase (a copy of the SF34).

I know all about the quality of french construction
though, I fly an ASW20F and drive a Peugeot......neither
is as well made as their german equivalents :-)