How Low to Spin??

Kirk Stant wrote:

I disagree with your conclusion about steep bank angles. It is
usually a lot harder to spin from a steep turn, and a lot easier to
recover from an incipient spin, for a simple reason (see Piggott for
more details): a properly flown steep turn is flown at a
significantly higher speed, and the elevator is limited, making it
harder to reach stalling angle of attack, and much easier to reduce
the angle of attack if needed due to the higher speed.

Not always true. An aircraft that has done a complete 180 during the
spin still has momentum, and is now to some degree flying backwards.
The excess forward momentum translates into excess reduction of airspeed.

Think about it for a minute. If you're going 50 knots in one direction,
and then one-half second later the nose of the glider is 180 degrees
pointed the other way, does this mean you are doing 50 knots in the other
direction? That's some G's, and I don't feel them in a spin.

This is why aircraft oscillate pitch up and down for a few turns before
stabilizing in a spin. For the first few turns, the aircraft momentum
is still slogging through the air.

But some of what you point out is true. Aircraft without enough
elevator authority to stall, and with forward CG, won't have the
ability to stall in a steep bank. But if the CG is back a bit, the
elevator has a lot of authority because the glider is designed for a
wide range of speeds, and the pilot has in aileron to resist overbanking,
then whoa nellie!

A properly flown steep turn at higher speed isn't what I'm talking about.
I'm considering a 30-45 degree bank turn at low speed.

You mention in an earlier post about making shallow, fast turns during
a low save. Why shallow? If the thermal is narrow, you usually need
to be steep (and fast) to stay in the (probably a bit turbulent) core.

This thermal was very smooth and regular and wide. I was feeling it
out on the first turn, and was not eager to make any coarse inputs or
lose sight of my landing site or get vertigo during the circle.

A shallow turn is asking for the classic base-to-final spin entry,
The classic spin entry from a shallow bank is uninteresting.
I won't be jamming in the rudder for a skid at some obviously
low speed close to the ground. I think the focus on the classic case
is niave and dangerous. Yes, it's easy to teach and demonstrate,
but it ignores too much. The more complex, less discussed
spin entry is the one in the accident reports: tight pattern,
higher speed, steep bank, lots of inside rudder, pilot focussed on
keeping the yaw string straight, quite a bit of opposite aileron
in the steep bank, in vertigo, pulling stick back to tighten up the
turn, and then wham! I'll look back through the accident reports, but
the ones I recall, and the B-52 and the DG spin I saw on video, involved
stabilized, 30-45 deg bank turns before each of the spins. In each,
it looked like the craft was overbanking, and the pilot put in more
opposite aileron and more elevator and WHAM! Instant spin...

Too much rudder, maybe, but it wasn't because he moved it. It was
because the pilot put in more dragging aileron without RELEASING
inside rudder.

unless you fly so fast that any climb is more luck than skill!

This is usually the case for me on cloudless days (like that one).
High over the terrain, I usually just bump into a thermal. Of course,
at altitude, while thermalling, slow is good, and trim is your friend...

Methinks your power background is showing (all those shallow turns!).

Shallow turns in power? Why? Just jam the throttle all the way in,
full flaps, and yo-yo base to final at 60 degrees. Gas is a good
substitute for brains ;PPPP

Power planes (except maybe the DA-20) often have lower
aspect ratios. Some even have frieze ailerons. And if the left turns
are flown with power off, there's even a little slip provided by the
P-factor of the prop. There's enough differences between the two
that the USA CFI practical tests require training and evaluation in each
category seperately (CFI transition from one to the other requires
spin training in the new class, except for Sport Pilots, but that's
another thread).

Even though I also have a power past going way back, I now find my
glider bias showing when I fly a stinkpot; I find myself whipping into
nice 45 to 60 degree banks, scaring the daylights out of my power-only
friends...

Power flying can be boring. If an autopilot can do it, why do they
need me?

Anyway Kirk, I welcome some more discussion. As you can see, there
are quite a few points where we agree, and a few nuanced ones where
we don't. I hope you have time to continue another response...
--

------------+
Mark Boyd
Avenal, California, USA

Bert Willing wrote:
Circling at 400ft while being able to land anywhere doesn't mean unsafe
operations by definition. I frequently start circling over a ridge at less
than half of this altitude. But not always.
Everything depends on experience (with that glider), current training level
(with that glider), personal daily fitness, wind conditions and lift
conditions.
And you have to put the question "is it safe" every single time - but then,
this does hold for every manoeuvre.
You just have to accept that sometimes the answer to this question is "no".

Experience is no panacea.

F1 - Francois De Klerk died in his Ventus 2cx. He entered a spin trying to save
a launch at 450". He was a national champion and one of the most experienced
contest pilots. Unfortunately he can't tell us whether it was disorientation,
turbulence, or wind shear that stalled him.

Unless the landing options are certain to include serious injury it must be
considered unwise to even think of trying to thermal under your safe spin
recovery altitude. It used to be with the draggy wodd and fabric jobs that
people generally got away with it low down, but a modern glass glider with
elliptical lift distribution departs violently into a spin and does not recover
in less than 500-600" (altitude loss after recovery is irrelevant)

So - my opinion is - the answer is always no, unless you have already put
yourself in the position where you are effectively already dead, and all the
possible outcomes are no worse. Personally I would prefer to avoid getting into
the situation in the first place...

Bruce Hoult wrote:

How about the opposite? I can't see much wrong with thermalling at 300
ft or lower if the ground underneath you is landable and unobstructed
such that you can roll level and land in any direction. Or on one of
those occasions where there is almost no lift about but no strong sink
either.

I've thermalled fairly low before. The main issues for me were to ensure
there was no traffic nearby, and avoid wires and towers. But yes, we
have a lot of flat, wide open dry plowed fields, so a landout is a
no-brainer.

I don't usually bother that low, however, because where I am, if I'm that
low, it's usually because it's early and the thermals aren't really cooking
yet. So that low there's often an inversion, and I'm gonna land anyway...
--

------------+
Mark Boyd
Avenal, California, USA

I wasn't there, didn't see the event nor know the place or the pilot.
(But then I guess most other posters don't, either.) This said...

thru a thermal and a release into sink. Our proud pilot was unable to
find the thermal

It might have been just a bubble. Happens a lot where I fly.

pattern and landing, he turned and climbed in this thermal. The IGC file
showed that his altitude at the time of encountering lift was 300 ft.

I more than once saved the day with a thermalling exercise at 300 ft
(with a chosen and reachable outlanding field, of course). Every serious
cross country pilot will enconter this situation sooner or later.
Whether it is appropriate in the circuit depends on the local situation
and the actual traffic, which I don't know.

asked him 1 question as he displayed this flight on See You. "How Low do
you want to spin?"

Why should he spin just because he thermals? Fly fast and carefully
enough and there's no reason why you should spin out of a thermal,
unless it's not extremly gusty.

spending a considerable amount of time in the mountains within 500 feet
of the terrain.

Which I consider absolutely normal in the mountains.

I am doubtful as to his ability to reach a landable area
during this portion of the flight.

In the mountains, the terrain often descends much faster than the
glider. So those 500 ft may be good for 20 miles. (Again, depends on the
local situation which I don't know.)

This pilot is in his first year of private ownership, cross county
soaring and may have almost 200 hours of total time.

If this is 200 hours in one year and cross country, then I would
consider this pilot as fairly current. 200 hours TT isn't exactly high
time, but it isn't beginner level, neither.

Again, I don't know the pilot. He may or may not be a bold, dumb and
reckless idiot. I'm just saying that your "facts" don't say anything
about the safety of the situation.

Stefan

Marc Ramsey wrote:

*Listen* to what Kirk (and others) have said about this. The last thing
you want to do when thermalling down low is use a shallow bank angle.
It is just too easy to lose track of what you are doing, and end up a
bit too slow in a skidding turn.

Kinda mixing apples and oranges here, aren't you Marc? If you're saying
that an uncoordinated slow shallow turn is less safe than a properly
coordinated 40-50 degree bank angle, that's not very interesting.

It is far safer to be in a properly
coordinated turn with a 40 to 50 degree bank angle. Every glider I've
ever flown gives a much better warning of impending departure in a tight
turn, plus the visual (nose above horizon) and physical (G forces
slacking off) cues are much more pronounced.

And how many pilots did this save from a spin? How many pilots
have died because of spins from the 40-50 degree bank angle vs.
the shallow bank angle?

What makes you think that the pilot who gets too slow in a shallow bank
won't do the exact same thing in a steep bank? Not enough elevator
authority? Maybe in a training ship, and then negative transfer to
a more controllable faster glass one?

Look at the fatal accidents and describe to me the "typical" spin
fatality. Then see if it matches the classic one (shallow bank).
In my reading, it does not...
--

------------+
Mark Boyd
Avenal, California, USA

I have read and re-read a couple of these postings and feel that while every
single one of us can point out a single instance when it may be okay for
this kind of behavior, I feel that if you ask yourself if you were the
instructor on the ground, watching a student pull this off, how would you
react? I think even the pilot who got away with it, should ask himself the
same question quietly while staring in the mirror...

I am not an instructor in sailplanes...but if my student did that,
well...we'd have a substantial "chat"...a "critique", if you will.

I think the whole thing boils down to one thing. How long do you wish to
participate in this sport? If it's a long time, then not contacting the
ground in a stall or spin will benefit that goal. If you have a blatant
disregard for you health and well being ( or mortality) then carry on. But
under no circumstance in my book, in a modern sailplane is this low of a
"save" a normal or good plan of action. The fact that the argument is
carrying on about how is it different from a rope break, is exactly how we
view autorotations in helicopter flying...we need to be prepared for the
worst, and so we practice them with instructors for checkrides...do you ever
see people go practice rope breaks on their own???

If you want to stay alive in this sport, you will adjust your assessment of
yourself to a more sustainable plan of action. I fly a DG-400, and once the
gear is down, the flaps down and the spoilers are cracked...we're
landing...no biggie...that's just the way it is. I commit to that act of
landing much higher away from the ground than some people...but I think it's
smart. 1000 feet is just a good all around safe AGL place to fully and
completely commit to land...can you be closer to the ground in the
mountains...or while ridge soaring....well...duh!!! that's not really the
point here though is it...?

I think I've added a full three cents worth now...I completely agree with
Eric Greenwell on the topic of the top competitors carrying safety to
amazing levels in their planning and throughout their flying...we should
too.

Steve.

Mark James Boyd wrote:
Marc Ramsey wrote:

*Listen* to what Kirk (and others) have said about this. The last thing
you want to do when thermalling down low is use a shallow bank angle.
It is just too easy to lose track of what you are doing, and end up a
bit too slow in a skidding turn.

Kinda mixing apples and oranges here, aren't you Marc? If you're saying
that an uncoordinated slow shallow turn is less safe than a properly
coordinated 40-50 degree bank angle, that's not very interesting.

No, I'm saying (based on experience) it's a lot easier to let yourself
slip (well, actually skid) into a dangerous uncoordinated turn from a
shallow bank, than it is from a steeper bank.

It is far safer to be in a properly
coordinated turn with a 40 to 50 degree bank angle. Every glider I've
ever flown gives a much better warning of impending departure in a tight
turn, plus the visual (nose above horizon) and physical (G forces
slacking off) cues are much more pronounced.

And how many pilots did this save from a spin? How many pilots
have died because of spins from the 40-50 degree bank angle vs.
the shallow bank angle?

Most pilots die spinning on the base to final turn, and they almost
always manage to do it from a slow shallow turn, rather than a slow
steep turn.

But, hey, we can agree to disagree, as long as we're not in the same
glider...

Marc

wrote in message ...
He definitely sounds like an accident waiting to happen.

Not so much the fact that he did some questionable things, but the fact
that he brags about them.

Eventually he will hit some big sink while over the mountains, and
realize he doesn't have an escape route. Hopefully the sink will let
up before he crashes, and it will cause him to reevaluate his risk
taking practices.

Of course, it might just be occasion for him to brag again about what
he got away with.

I have had the pleasure of seeing Ted get started in his cross country
flying. I don't consider him an overt risk taker and most, if not
all, of the advice he receives from our club members encourages
caution. I am pleased he wanted to discuss this experience with me.
He wanted my honest feedback, I gave it, and he accepted it. I saw no
bragging.


Andy (GY)

Eric,

Well said.

To reemphasize, contest pilots do not put their aircraft or lives at
risk for the sake of points. They make balanced decisions. If they
appear to some to be "dangerous," it probably points to a difference
in skill and experience between the performer and the observer. Don't
get into the habit of assuming that the only way to win is to take
unreasonable risks. Such thinking can get you into far more trouble
than you (or any other pilot) could hope to handle.

Eric Greenwell wrote in message ...
Ted Wagner wrote:

Thanks Shawn, I'll take a look.

Btw, so say "It's *safe* to say everyone should land (blah blah blah)" is,
well, stating the obvious (kinda like saying "It's safe to stay on the
ground"). The pertinent question is whether it was *unsafe* for me to
continue the turn in the precise circumstances in which I found myself. I
remain open to the possibility that it was not, but in the same spirit,
being over tiger country out of reach of landable points is questionably
unsafe, yet I hear regularly of pilots doing this as a matter of routine,
especially in contests,

We must know entirely different groups of pilots, because I sure don't
hear pilots talking about this, unless it starts out "Boy, did I screw
up today...". The story often ends with "... so I ended up ground
looping (or "scaring myself sh--less", "hitting the fence", "breaking
the tail", etc)".

and if I continue flying contests long enough (and I
hope to be doing them for many years), I will have to take that step many
times myself.

No, you certainly don't have to. Pilot's choice, you know. It some areas
in some conditions, the lift can be so reliable that you can actually
count on it, but if done regularly, you will find the times when you
misjudge the weather.

I want to err on the side of safety, but at the same time, I
want to be reasonable and competitive.

Take a look at the flight traces from the top pilots. See if they are
really taking these chances. The ones I've flown with didn't seem to
take these kinds of chances. I think the philosophy for many of them is
"there is always another day and another contest, and if you break your
glider, you won't even win this day or this contest".

Mark James Boyd wrote:

And how many pilots did this save from a spin? How many pilots
have died because of spins from the 40-50 degree bank angle vs.
the shallow bank angle?

What makes you think that the pilot who gets too slow in a shallow bank
won't do the exact same thing in a steep bank? Not enough elevator
authority? Maybe in a training ship, and then negative transfer to
a more controllable faster glass one?

I suggest the elevator authority isn't any greater on a faster glass
ship because there is no need for it. My experiences in a Blanik L13,
Ka-6e, Libelle h301, Std Cirrus, ASW 20C, and an ASH 26 E were the same:
they were much harder to stall at 30-35 degrees than 10 or 15, and I
couldn't stall them above 45 degrees. This is in coordinated circling
flight.
--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA