In wave, in blue hole at cloud level, hole closes, in IMC, then what?

On Wed, 08 Apr 2015 07:08:34 -0700, son_of_flubber wrote:

My glider is capable of benign spiral. I open the spoilers, (already
trimmed to 50 knots) and let go of stick and rudder.

I started a cloud-flying course last year and one of the first things we
were told was that, if you loose it in cloud, leave the trim where it
was, fully open the brakes and use feet and hand(s) to keep all controls
central, i.e. DON'T let go of the stick or take your feed off the pedals.

This takes advantage of the fact that most gliders are stable with brakes
open and controls centralised and not flapping about. Don't forget that
if the glider is pulling any G the stick can flop over and move elevator
and/or ailerons away from neutral if you're not holding it central.

Something similar might also occur in strong turbulence. If the stick is
raked or Z-shaped like a Libelle's, then its CG is behind the pivot, so
if you're pulling either positive or negative G than the offset stick
weight will tend to increase that if you're not holding the stick to stop
that happening.

A bit later in the season I did indeed loose it when LK8000 sounded an
airspace warning during a cloud climb and I manoeuvred too fast when
trying to avoid breaking into the bottom of the airspace. So, I did as
I'd been told and opened the brakes and then held the stick central and
the rudder straight. The glider, my Standard Libelle so fitted with weak
brakes, zoomed around a bit but didn't pull noticeable G or exceed Vne.
In fact I didn't notice it even exceeding Va. It came out the bottom of
the cloud more or less upright, so returning to straight and level was
perfectly straight-forward and didn't cost me more than 100 feet of
height.

Suggestions?

Do as I did if you don't pop out of the cloud fairly soon: this assumes
you were cruising in a straight line when the cloud got you and trimmed
more or less at Vbestglide. Open the brakes and centralise controls
immediately if you see the airspeed changing because that means you've
been upset by turbulence.

You'll have time to think about bail-out procedures later when you're
sitting, holding the controls centralised and waiting to exit the cloud.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On 4/8/2015 8:08 AM, son_of_flubber wrote:
So I'm flying in a blue hole in wave lift of 5 m/s, trimmed to 50 knots, in
clear air with a cloud layer upwind and downwind, cloud top above and cloud
base below. Suddenly I find myself in IMC. What are my options?

My glider is capable of benign spiral. I open the spoilers, (already
trimmed to 50 knots) and let go of stick and rudder. Then I mentally
rehearse my bail out procedure and expect to come out below the cloud (or
possibly above). It seems like I should decisively and without hesitation
initiate the spiral ASAP, while the glider is still relatively level and at
cruising airspeed.

Suggestions?


In re Bob K.'s and Steve L.'s comments elsewhere on this branch, "Ha ha ha. Oh
the knowing joy of those familiar with 90-degree landing flaps (and I'm one of
'em)!!!" Regrettably (in subsequently broken ship/traumatized pilot terms),
that particular religious war was lost long, long ago.

An argument can be reasonably made that - in "tribal knowledge" terms - there
is nothing new to be learned from the Easter Sunday Reno accident. That said,
I understand that in *individual* terms there is *always* something to gleaned
from such things...and I hope by such gleaning some may avoid finding
themselves in similar dire circumstances.

As first-hand-experience(s) have noted in another branch of this thread,
apparently not all gliders have a "you can comfortably bet your life on it
being 'a good enough' benign spiral capability," that I would willingly bet
*my* life on it. That said, if - for whatever reason - Joe Glider Pilot
develops a sense that unwanted IMC is in a flight's future, I sure hope he's
done-through-practice-beforehand what he intends to do soon! My own
spoilered-ship preference would be to initiate the 'save your butt disaster
plan' *before* loss of visual conditions, but that's just me. My guess is
Martin G.'s post-IMC-entry advice is generically sensible, too.

As always, the devil is in the details, and YMMV...

Bob W.

Find an instructor with much wave experience and ask them to help you come up with a plan and some training. Some gliders will do a benign spiral well, others will not. Get some benign spiral training then try it in your glider to see under what conditions it will or will not have a benign spiral.. Get an instant on AH. I would be very hesitant to open the spoilers at high speed, there was a discussion about that a month or two ago. I have flown many complex aircraft and I think one thing gliders pilots do not do very well is to seek recurrent training from a qualified instructor. When I was actively flying gliders I trained every year with an instructor, spins, spiral dive and I always asked them to surprise me with something we had not covered before (just now getting back into gliding after a long absence). In the other complex type aircraft I trained every 3 to 6 months. Most glider pilots only get recurrent training every biannual. I like to know what to do during an emergency rather than figure it out at the time.

I have experienced multiple inflight emergencies and in all but one case my training took over and no thought was involved, just muscle memory. However, the case I had not trained for was one throttle cable coming loose on final with the engine immediately going to full throttle. My very first thought was "we never covered this in training". It would be best just to rely on muscle memory. As a side note, it was a big cabin class twin and after a moment of thought I feathered the engine and continued to landing on the one good engine.

In climbing we always said plan for the worse, hope for the best. Training, training. Maybe one of the experienced legends of the sport can comment here and add guidance.

One more thought. In the war bird community we had hanger flying sessions were we talked about the emergencies we experienced and how we handled them.. These were priceless sessions! I learned what other pilots did in situations I had never thought of. Maybe we should start a hanger flying session on this site!

On 4/8/2015 1:00 PM, Jonathan St. Cloud wrote:

Good stuff snipped...
In climbing we always said plan for the worse, hope for the best. Training,
training. Maybe one of the experienced legends of the sport can comment
here and add guidance.

One more thought. In the war bird community we had hangar flying sessions
where we talked about the emergencies we experienced and how we handled
them. These were priceless sessions! I learned what other pilots did in
situations I had never thought of. Maybe we should start a hangar flying
session on this site!


From the numerous-n-rapidly-arriving comments related to Bob Spielman's
IMC-related bailout, I'd guess the situation hits close to home for many
thoughtful gliderpilots...

I'll second the idea of Real Worth being found in hangar flying sessions, even
if only the unvoiced thought, "You gotta be kidding!" Thanks to everyone who's
shared so far!

Bob W.

On Wed, 08 Apr 2015 11:41:01 -0600, Bob Whelan wrote:

In re Bob K.'s and Steve L.'s comments elsewhere on this branch, "Ha ha
ha. Oh the knowing joy of those familiar with 90-degree landing flaps
(and I'm one of 'em)!!!" Regrettably (in subsequently broken
ship/traumatized pilot terms), that particular religious war was lost
long, long ago.

Around 2004 there was another benign spiral thread which caused me to be
a bit of experimenting in an ASW-20. I found that, in calm evening air
trimmed for best glide (57 kts) and zero flap (position 3) and flying
straight, it slowly developed a 25 second phugoid oscillation with an
associated +/- 5kt speed oscillation.

I also tried for a benign spiral: zero flap, wheel down and brakes out,
same trimmed speed and going hands free after setting up a 20-30 degree
bank. After even half a circle the bank angle had increased, the nose had
dropped the speed was increasing. I never let it go beyond that point and
concluded that the ASW-20 doesn't have a benign spiral.

I haven't tried either experiment with the Libelle but should do so this
season, as its always good stuff to know. BTW, my H.201 is s/n 82, so it
dates from before the move to the B series, so it has balsa sandwich
flying surface skins, the small tailplane and upper and lower surface
brakes.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Wednesday, April 8, 2015 at 3:02:26 PM UTC-4, Martin Gregorie wrote:

concluded that the ASW-20 doesn't have a benign spiral.

It's ship/setup dependent.

In my 20B, what works is landing flaps, gear down, spoilers full out. My CG is pretty far back.

Round and round and round at about 50 kts. Top rudder makes it even more stable.

T8's hot tip for partial panel descents: get the glider dirty (i.e. spoilers, flaps, gear). It's about 1000x easier to fly a dirty glider on instruments than a clean one.

Evan Ludeman / T8

On 4/8/2015 1:28 PM, Tango Eight wrote:
Snip...

T8's hot tip for partial panel descents: get the glider dirty (i.e.
spoilers, flaps, gear). It's about 1000x easier to fly a dirty glider on
instruments than a clean one.

I lack the experience to express an informed opinion about that
paragraph-ending statement (though I'd wager a 6-pack it's correct), but will
readily second the idea of adding all the disposable drag your glider has as
being a Great Idea if/when things get visually dodgy. It's hard to get more
stable than a glider with so much drag it can't do anything but slowly and
stably fall to earth like a featherweight shuttlecock, regardless of what Joe
Pilot might attempt with the stick.

Short list of gliders which qualify follows:

Bob W.

P.S. For any offended HP drivers out there, please note I qualified things
with "slowly and *stably* fall to earth...". My HP 14 fell to earth quite
slowly and UNstably with full flaps and no hands/feet on the controls, and
never exceeded ~50 knots regardless of any of the "unusual attitudes" it found
while bouncing between the tail-high/nose-low state and "various sideways
states" as it alternated between stalled with full flaps and not stalled with
full flaps. To avoid stalling, one merely had to hold sufficient forward stick
to maintain 40 knots or so. Quite instructive...

On Wednesday, April 8, 2015 at 1:30:23 PM UTC-7, Bob Whelan wrote:
On 4/8/2015 1:28 PM, Tango Eight wrote:
Snip...

T8's hot tip for partial panel descents: get the glider dirty (i.e.
spoilers, flaps, gear). It's about 1000x easier to fly a dirty glider on
instruments than a clean one.

I lack the experience to express an informed opinion about that
paragraph-ending statement (though I'd wager a 6-pack it's correct), but will
readily second the idea of adding all the disposable drag your glider has as
being a Great Idea if/when things get visually dodgy. It's hard to get more
stable than a glider with so much drag it can't do anything but slowly and
stably fall to earth like a featherweight shuttlecock, regardless of what Joe
Pilot might attempt with the stick.

Short list of gliders which qualify follows:

Bob W.

P.S. For any offended HP drivers out there, please note I qualified things
with "slowly and *stably* fall to earth...". My HP 14 fell to earth quite
slowly and UNstably with full flaps and no hands/feet on the controls, and
never exceeded ~50 knots regardless of any of the "unusual attitudes" it found
while bouncing between the tail-high/nose-low state and "various sideways
states" as it alternated between stalled with full flaps and not stalled with
full flaps. To avoid stalling, one merely had to hold sufficient forward stick
to maintain 40 knots or so. Quite instructive...

It was probably emphasized elsewhere already in this thread, but worth emphasizing again, that many gliders have speed limits for positive flaps. In a 27 at VNE you can only be on negative flap. Not even neutral flap 3 (which I find it odd). So you really need to maintain relatively slow speed to fly really dirty in those gliders, especially with landing flaps.

Ramy

This thread is off the rails. OP posed a scenario involving IMC in smooth lift at low speed. Now guys are complaining that some of the tips given won't work at redline in rough air. Well that's true. It shouldn't really be a surprise now, should it?

-Evan Ludeman / T8

On Wednesday, April 8, 2015 at 8:37:02 PM UTC-7, Tango Eight wrote:
This thread is off the rails. OP posed a scenario involving IMC in smooth lift at low speed. Now guys are complaining that some of the tips given won't work at redline in rough air. Well that's true. It shouldn't really be a surprise now, should it?

-Evan Ludeman / T8

And the scenarios were folks are breaking gliders in wave, at least in the big Sierra wave are just not that scenario, so it's not particularly interesting to other folks here, who may be trying to get the topic on a rail relevant to actual problems experienced in real wave flying ... :-) Well stuff that has at least eaten two gliders in the Reno areas.

The Sierra wave scenario is really being closed in IMC near VNE in smooth air (if bombing along you are maybe 10,000'or so higher than the rotor). No turbulence necessary to have a very bad day.