Avoiding Vne

Yesterday evening I talked with a friend about avoiding excessive speed when
recovering from a spin in a modern low drag glider with the somewhat larger
span.
He came up with the idea of pulling the airbrakes when still recovering from
the rotating mode. I am not sure this can be done without disturbing the
recovering action or without hurting the glider.
Any comment will appreciated.

Karel, NL

K.P. Termaat wrote:
Yesterday evening I talked with a friend about avoiding excessive speed when
recovering from a spin in a modern low drag glider with the somewhat larger
span.
He came up with the idea of pulling the airbrakes when still recovering from
the rotating mode. I am not sure this can be done without disturbing the
recovering action or without hurting the glider.
Any comment will appreciated.

Karel, NL



Pulling the airbrakes is what most handbooks say on this subject. But if
you're already very fast I'd do this carefully.

If you are already very fast and pull the airbrakes, you have to be very
careful during the pull up because the wing won't stand the same g-load as
without airbrakes.

--
Bert Willing

ASW20 "TW"


"Erik Braun" a écrit dans le message de
...
K.P. Termaat wrote:
Yesterday evening I talked with a friend about avoiding excessive speed
when
recovering from a spin in a modern low drag glider with the somewhat
larger
span.
He came up with the idea of pulling the airbrakes when still recovering
from
the rotating mode. I am not sure this can be done without disturbing the
recovering action or without hurting the glider.
Any comment will appreciated.

Karel, NL



Pulling the airbrakes is what most handbooks say on this subject. But if
you're already very fast I'd do this carefully.

must have slipped my notice that airbrakes on 'modern
low drag gliders' were speed limiting. my speed stays
pretty much constant at full travel. notwithstanding
that, why on earth would you want to increase your
sink rate further than that caused by the spin in the
first place. sounds like a death wish to me!

do what you were taught in your spin training, its
a recovery drill not a starting pint to experiment
with your life and possibly the life of your passenger/pupil.

At 09:36 25 March 2004, Erik Braun wrote:
K.P. Termaat wrote:
Yesterday evening I talked with a friend about avoiding
excessive speed when
recovering from a spin in a modern low drag glider
with the somewhat larger
span.
He came up with the idea of pulling the airbrakes
when still recovering from
the rotating mode. I am not sure this can be done
without disturbing the
recovering action or without hurting the glider.
Any comment will appreciated.

Karel, NL



Pulling the airbrakes is what most handbooks say on
this subject. But if
you're already very fast I'd do this carefully.

Hello Erik,

Yes that's what my handbook says for my Ventus-2cxT also.
I guess however that when recovering from a spin using the standard method
(or the more advanced one including a bit of aileron) that then Vne will be
exceeded after rotation has stopped and pitch angle is something like 60°.
To avoid this the idea is to pull the brakes even before the rotation has
stopped. But I am worried about that.

Karel, NL

"Erik Braun" schreef in bericht
...
K.P. Termaat wrote:
Yesterday evening I talked with a friend about avoiding excessive speed
when
recovering from a spin in a modern low drag glider with the somewhat
larger
span.
He came up with the idea of pulling the airbrakes when still recovering
from
the rotating mode. I am not sure this can be done without disturbing the
recovering action or without hurting the glider.
Any comment will appreciated.

Karel, NL



Pulling the airbrakes is what most handbooks say on this subject. But if
you're already very fast I'd do this carefully.

OK the answer to this one is very simple, VNE stands
for 'Velocity never exceed' the never is not optional.
Pulling the airbrakes or pulling back hard on the stick
may cause structural damage to the glider, however
this structural damage is not likely to be catastrophic.
Exceeding VNE may induce aerodynamic flutter, this
can and almost certainly will cause catastrophic failure
of the airframe. Put simply try and avoid both but
if the choice is exceed the placarded G loading or
VNE the G loading is the only choice. The potential
for catastophic failure is much much greater if VNE
is exceeded, exceeding VNE is therefore not an option.

I have no doubt there will now be lots of postings
from people who say they have exceeded VNE and got
away with it. Even idiots can be lucky sometimes.

At 11:30 25 March 2004, Bert Willing wrote:
If you are already very fast and pull the airbrakes,
you have to be very
careful during the pull up because the wing won't stand
the same g-load as
without airbrakes.

--
Bert Willing

ASW20 'TW'


'Erik Braun' a écrit dans le message de
...
K.P. Termaat wrote:
Yesterday evening I talked with a friend about avoiding
excessive speed
when
recovering from a spin in a modern low drag glider
with the somewhat
larger
span.
He came up with the idea of pulling the airbrakes
when still recovering
from
the rotating mode. I am not sure this can be done
without disturbing the
recovering action or without hurting the glider.
Any comment will appreciated.

Karel, NL



Pulling the airbrakes is what most handbooks say on
this subject. But if
you're already very fast I'd do this carefully.

Don Johnstone wrote:

OK the answer to this one is very simple, VNE stands
for 'Velocity never exceed' the never is not optional.
Pulling the airbrakes or pulling back hard on the stick
may cause structural damage to the glider, however
this structural damage is not likely to be catastrophic.

Why not?


Exceeding VNE may induce aerodynamic flutter, this
can and almost certainly will cause catastrophic failure
of the airframe. Put simply try and avoid both but
if the choice is exceed the placarded G loading or
VNE the G loading is the only choice. The potential
for catastophic failure is much much greater if VNE
is exceeded,

Why?

exceeding VNE is therefore not an option.

Isn't there a built in safety margin for both G's and VNE?


I have no doubt there will now be lots of postings
from people who say they have exceeded VNE and got
away with it. Even idiots can be lucky sometimes.

Don Johnstone wrote:
OK the answer to this one is very simple, VNE stands
for 'Velocity never exceed' the never is not optional.
Pulling the airbrakes or pulling back hard on the stick
may cause structural damage to the glider, however
this structural damage is not likely to be catastrophic.

"May"? At Vne, "pulling back hard on the stick" will guarantee
catastrophic structural failure, not just "damage". Even "pulling back
modestly" (like one-third of the stick travel) can get you very close to
the limits.

Exceeding VNE may induce aerodynamic flutter, this
can and almost certainly will cause catastrophic failure
of the airframe.

References? The majority of people I know that have suffered flutter did
so without catastrophic failure. The glider often had damage to a
control surface or linkage, but not structural damage.

Put simply try and avoid both but
if the choice is exceed the placarded G loading or
VNE the G loading is the only choice. The potential
for catastophic failure is much much greater if VNE
is exceeded, exceeding VNE is therefore not an option.

References?

I have no doubt there will now be lots of postings
from people who say they have exceeded VNE and got
away with it. Even idiots can be lucky sometimes.

Inadvertently exceeding Vne doesn't automatically make the pilot an
idiot. Most of these "idiots" will be good pilots that got caught in a
bad situation; some might be pilots that took exceptional risks. Anyway,
we are talking about what to do when caught between a rock and hard
place, not what led to it. Let's not prejudge anyone.


--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Hi guys,

Thanks for the discussion. Once one has exceeded Vne a choice must be made
by the pilot of either pulling the airbrakes or put some backpressure on the
stick or do both. We know the dramatic outcome of the Nimbus 4DM at Minden a
couple of years ago when doing the latter. Probably I would go for only
putting some backpressure on the stick and have the max g-load number for
the wing available. Hopefully the wing will survive flutter that may occur
and will not destroy the whole wing. Some years ago I saw and heard a tail
of a Cirrus move about heavily in a too fast fly by, but the glider survived
with minimum damage.
However the above is not my concern. I am worried about a possible means to
avoid Vne to be exceeded after recovery when the glider is still in its
spinning (rotation) mode. The idea is to pull the airbrakes even before the
rotation has stopped.

Karel, NL


"K.P. Termaat" schreef in bericht
...
Hello Erik,

Yes that's what my handbook says for my Ventus-2cxT also.
I guess however that when recovering from a spin using the standard method
(or the more advanced one including a bit of aileron) that then Vne will
be
exceeded after rotation has stopped and pitch angle is something like 60°.
To avoid this the idea is to pull the brakes even before the rotation has
stopped. But I am worried about that.

Karel, NL

"Erik Braun" schreef in bericht
...
K.P. Termaat wrote:
Yesterday evening I talked with a friend about avoiding excessive
speed
when
recovering from a spin in a modern low drag glider with the somewhat
larger
span.
He came up with the idea of pulling the airbrakes when still
recovering
from
the rotating mode. I am not sure this can be done without disturbing
the
recovering action or without hurting the glider.
Any comment will appreciated.

Karel, NL



Pulling the airbrakes is what most handbooks say on this subject. But if
you're already very fast I'd do this carefully.

Pete Zeugma wrote:

must have slipped my notice that airbrakes on 'modern
low drag gliders' were speed limiting. my speed stays
pretty much constant at full travel.

Of course, if the glider is already running at Vne I wouldn't pull the
airbrakes but try to recover really carefully. But up to ~220kmh, I'd do
this, because they DO produce a big drag an make the glider slower (in
my experience at least, which doesn't include a Nimbus or the other big
ones).

Erik