Overspeed Recovery question

On Thursday, February 12, 2015 at 3:59:16 PM UTC+13, Bill D wrote:
On Wednesday, February 11, 2015 at 6:49:09 PM UTC-7, Bruce Hoult wrote:
On Thursday, February 12, 2015 at 12:07:31 PM UTC+13, wrote:
On Tuesday, February 10, 2015 at 6:58:58 PM UTC-8, wrote:
If you inadvertently fly into the yellow range and kiss the red range, and you get into the high speed vibration, what is the best way to slow before the wings depart the glider. My sense is to reach for the spoilers and slowly extend to slow. Any opinions on that matter?

Thanks all for your input. The senario as stated in my quest has happened to me several times whilst flying Condor - Glider flight Simulation software. I've been deploying spoilers to slow down but that I would ask this group in case it happens in a real glider. Your inputs, as I suspected, are well thought out and are convincing. My thoughts to control highspeed flight (overspeed flight) will be pitch.

The flutter in condor is nasty, and happens at speeds well below where any real glider would probably experience flutter. The simulated glider also falls apart very very quickly!

Have a lot of experience at that?

Yes. Real gliders I've flown have never fluttered at indicated Vne at low altitude. Condor does every time.

On Thursday, February 12, 2015 at 7:55:09 AM UTC-5, Tango Eight wrote:
On Wednesday, February 11, 2015 at 6:07:31 PM UTC-5, wrote:

Thanks all for your input. The senario as stated in my quest has happened to me several times whilst flying Condor - Glider flight Simulation software. I've been deploying spoilers to slow down but that I would ask this group in case it happens in a real glider. Your inputs, as I suspected, are well thought out and are convincing. My thoughts to control highspeed flight (overspeed flight) will be pitch.

Illustrating nicely the perils of self directed training in Condor. You did well to ask for the benefit of real world experience.

Evan Ludeman / T8

Yes, good to ask real world experience. While I've never been in the scenario as described (over VNE unintentionally) I have had dive brakes open at speed.
Coming back from a day of flying, I did a speed pass over the field (in a ASW-24) aiming to do a pull up and enter late downwind. At ~300' (in the pull up), I hit a gust that slammed the spoilers full open (speed was likely close to 180MPH) and aimed away from the field.
The glider felt like it hit a wall.
I went from, "Life is good, lets do a nice pattern" to "I'm low, losing speed quickly and am getting a wee bit busy".
The spoilers DID close and everything turned out well.
We did spend some time checking spoiler linkages & alignments before de-rigging.

As to flutter, I would hazard it's more of the control surface balance, hinge condition & linkage slop than the wing itself. The wing tends to be involved AFTER the control surface flutters.
Right on up there with old/cheap safety tape that peels up its leading edge and blanks a surface. Especially newer designs with small chord control surfaces.

At 15:10 11 February 2015, Dan Marotta wrote:
How can you "inadvertently fly into the yellow range and kiss the red
range"? Sleeping at the helm? You have to have quite a nose down
attitude to get near the red line and it doesn't sneak up on you. It's
very noisy and pitch sensitive.

Don's advice below is excellent.


On 2/11/2015 3:20 AM, Don Johnstone wrote:
At 02:58 11 February 2015, wrote:
If you inadvertently fly into the yellow range and kiss the red range,
and

you get into the high speed vibration, what is the best way to slow
before

the wings depart the glider. My sense is to reach for the spoilers
and
slo
wly extend to slow. Any opinions on that matter?

A very experienced test pilot once told me, and several others, that if
you
were faced with exceeding VNE you should pull as hard as you can, even
if
it means exceeding max G load, to reduce speed as soon as you can to
below
VNE. Catastrophic structural failures due to excess G are very rare
unless
there are other factors, catastrophic failures due to flutter are
almost


inevitable.
There is no right answer, just a less wrong one and I would stress I
have
not had the opportunity to test this.
One of the requirements on a Grob 103 post major inspection test flight
was
to operate the spoilers at 70kts, having done this many times I would
not
recommend the spoilers option.


--
Dan Marotta


Once, while practicing aerobatics in my Pilatus B4, and entirely due to my

own clumsiness, I found myself in a 45 degree inverted dive and rapidly
approaching Vne. Fortunately, I did what I was trained to do, which was to

push hard until the nose was above the horizon, then roll out. It was all
captured on my cockpit mounted Go-Pro. This shows the momentary
hesitation while I overcame the instinct to pull. The ASI shows 130knots
(Vne) was just touched, and the accelerometer, after initially being
obscured
by my left arm rising to be firmly held against the canopy, showed -4g.

Had I pulled through, I would probably have exceeded Vne by 30knots.

On landing, the aircraft was thoroughly checked, and found to have suffered

no ill effects.

I am thankful for the thoroughness of my training, and for the robustness
of
the B4.

At 16:12 12 February 2015, Michael Corcoran wrote:
At 15:10 11 February 2015, Dan Marotta wrote:
How can you "inadvertently fly into the yellow range and kiss the red
range"? Sleeping at the helm? You have to have quite a nose down
attitude to get near the red line and it doesn't sneak up on you. It's
very noisy and pitch sensitive.

Don's advice below is excellent.


On 2/11/2015 3:20 AM, Don Johnstone wrote:
At 02:58 11 February 2015, wrote:
If you inadvertently fly into the yellow range and kiss the red
range,
and

you get into the high speed vibration, what is the best way to slow
before

the wings depart the glider. My sense is to reach for the spoiler
and
slo
wly extend to slow. Any opinions on that matter?

A very experienced test pilot once told me, and several others, that
if
you
were faced with exceeding VNE you should pull as hard as you can,
even
if
it means exceeding max G load, to reduce speed as soon as you can to
below
VNE. Catastrophic structural failures due to excess G are very rare
unless
there are other factors, catastrophic failures due to flutter ar
almost


inevitable.
There is no right answer, just a less wrong one and I would stress
have
not had the opportunity to test this.
One of the requirements on a Grob 103 post major inspection test
flight
was
to operate the spoilers at 70kts, having done this many times I woul
not
recommend the spoilers option.


--
Dan Marotta


Once, while practicing aerobatics in my Pilatus B4, and entirely due to m

own clumsiness, I found myself in a 45 degree inverted dive and rapidly
approaching Vne. Fortunately, I did what I was trained to do, which was t

push hard until the nose was above the horizon, then roll out. It was all

captured on my cockpit mounted Go-Pro. This shows the momentary
hesitation while I overcame the instinct to pull. The ASI shows 130knots
(Vne) was just touched, and the accelerometer, after initially bein
obscured
by my left arm rising to be firmly held against the canopy, showed -4g.

Had I pulled through, I would probably have exceeded Vne by 30knots.

On landing, the aircraft was thoroughly checked, and found to have
suffere

no ill effects.

I am thankful for the thoroughness of my training, and for the robustnes
of
the B4



I'm Genuinely relieved that the original poster is not a trained glider
pilot,because most people once trained are so used to speed control the
situation does not occur.
Which is why we have been talking about loosing control in clouds or
failing
to allow for the reduced VNE at altitude.
Presumably if you fly high enough you can get to a coffin corner where the

stall speed is higher than the hight adjusted VNE but we should be so lucky

as to get there.
I was impressed with the pushing to recover from an inverted dive ,not
something to try without proper training.
Fun thread ,hope the snow melts soon.

I'm Genuinely relieved that the original poster is not a trained glider
pilot,because most people once trained are so used to speed control the
situation does not occur.
Which is why we have been talking about loosing control in clouds or
failing
to allow for the reduced VNE at altitude.
Presumably if you fly high enough you can get to a coffin corner where the

stall speed is higher than the hight adjusted VNE but we should be so lucky

as to get there.
I was impressed with the pushing to recover from an inverted dive ,not
something to try without proper training.
Fun thread ,hope the snow melts soon.

I originally posted the question and actually, I am a trained and rated glider pilot and in addition to my 28,000 hours of flight time, I'm type rated in 747, 767, 737, DA20. In my glider training, I was trained to avoid VNE but am aware that there are circumstances where one can find himself (in this case it was in CONDOR flight simulaton) in rapid buildup of speed that continues on through the yellow arch and rapidly approaches VNE. I've encountered that very situation at high altitude in Jet aircraft, in heavy mountain wave conditions. In those instances, the only available action is to kill some lift by carefully extending spoilers - it works well but gliders are a different animal and and this forum is an excellent place to go when one has a question.

On Thursday, February 12, 2015 at 4:41:17 PM UTC+13, Jonathan St. Cloud wrote:
Oh, a quick way to tell if a spin has turned into a spiral, when the rudder does not stop the spin.

Should have thought the rapidly increasing wind noise and G forces would rather give it away...

I would recommend going up with a competent instructor and trying it for yourself. First thing I noticed was rudder did not stop the spin. By the time you notice the increase in airspeed you will be going very fast. Nothing beats first hand experience!

On Friday, February 13, 2015 at 3:30:09 AM UTC-5, Bruce Hoult wrote:
On Thursday, February 12, 2015 at 4:41:17 PM UTC+13, Jonathan St. Cloud wrote:
Oh, a quick way to tell if a spin has turned into a spiral,
when the rudder does not stop the spin.

Should have thought the rapidly increasing wind noise and G forces
would rather give it away...

Some very experienced pilots have made the mistake of
interpreting a spiral dive as a spin. IIRC this was how
an Eta was lost during spin test (pilots bailed out OK).

So, its not necessarily so easy to distinguish,
especially in clean quiet fast gliders...
In the briefing prior I first flew an Antares I was
specifically warned on this...

Be careful out there,
Best Regards, Dave

On Tuesday, February 10, 2015 at 9:58:58 PM UTC-5, wrote:
If you inadvertently fly into the yellow range and kiss the red range, and you get into the high speed vibration, what is the best way to slow before the wings depart the glider. My sense is to reach for the spoilers and slowly extend to slow. Any opinions on that matter?

ask this guy:

https://www.youtube.com/watch?v=kQI3AWpTWhM

Quoting from The Handbook of Glider Aerobatics by Peter Mallinson and Mike Woollard.

"Effect of Airbrakes
Contrary to popular belief, use of the airbrakes does cause a significant increase in the loads applied to the glider, requiring a moderation of the Flight Envelope in a similar way to the ailerons..The reasons are twofold:

(a)the airbrakes destroy lift over a fairly large inboard section of the wing causing the spanwise wing lift distribution to move outboard. This substantially increases wing bending moments.

(b)the airbrakes also generate drag loads on the wing, a proportion of which become an additional load in the pitch plane direction.

JAR22.345 specifies that the maximum positive load factor limits should reduce to not less than 3.5G with airbrakes fully deployed.

It is nearly always better to slow a glider by pulling G rather than opening the airbrakes."