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How Low to Spin??



 
 
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  #81  
Old August 27th 04, 07:02 PM
Kirk Stant
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(Mark James Boyd) wrote in message news:[email protected]

You have a BBQ and beer cooler in the nose? How inventive...
I suppose your landouts are quite a party...


You bet!

In an aileron roll, the head is moved. In max dutch rolls
45 to 45, the head is moved. So again, I guess you are agreeing with
me that high roll rates and steep banks can induce vertigo.
If you don't agree. Take a pax at night cover all instruments.
Head perfectly straight ahead. Close eyes. Then max roll rate
left 45 bank, then 90 degrees of turn, slow roll right,
and tell them to open eyes while level and recover. Fun, huh?


No, I do not agree with you that high roll rates and steep banks
induce vertigo. It's the disconnect between what you see, and what
the inner ear feels, that causes vertigo. If you can see the horizon,
then as long as you don't make a sudden movement of your head in a
"wrong" direction (which depends on which way the plane is moving"),
you should not experience vertigo. But close your eyes, or fly into a
cloud, and even a small roll or pitch rate can induce vertigo. Unless
you are thermalling with your eyes closed (reminds me of some pilots I
know!) or in a cloud (not common in the US), vertigo should not be a
problem in a glider, no matter how fast you roll or steep you turn.
Now, I will caveat that statement with the observation that it is
possible to trigger vertigo in some individuals by a sudden (and I
mean unusually rapid) head movement at the same time as the plane is
rolling - and that should be taught to pilots, just like IFR pilots
are shown how lack of outside references can lead to vertigo. But you
shouldn't be jerking your head around while flying!

And yes, lack of coherent outside reference is important too.
Pretty easy to get when looking at clouds and fog and mountainsides...
And sometimes tough to correct without...
wait for it...moving your head


You don't need a lot of outside references to maintain your attitude -
but yes (as I say above), when you lose outside references, you are
vulnerable to vertigo. But to get a glider into a situation where
there are no useful outside references is a bad thing.

The only disadvantages I can find of very effective spoilers a

1) If they ain't locked for takeoff, a gnarly pio
2) If they don't have very fine controls, hard to be precise
about glide slope.
3) If at max out, landing flare is VERY fast, and stall speed
increased


1. Use a checklist. Oh, and why is the tow pilot fanning his rudder
at me?
2. G-103s are horrible in this respect. Most gliders are fine.
3. You don't have to land with them all the way out, but it's nice to
have the option.

Kirk
Ads
  #82  
Old August 27th 04, 08:19 PM
Robert Ehrlich
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Marc Ramsey wrote:

Mark James Boyd wrote:
For some of us with less currency and less practice in type,
this could be quite dangerous. Vertigo, inadvertent coarse use
of controls (including roll), imperfect centering technique,
visual illusions due to wind and movement of the ground,
different pressure feel caused by different gliders or
C.G.'s, etc. can make this more hazardous.


Well, I disagree, and I strongly believe that a well-trained glider
pilot, in any glider, low or high, should be every bit as comfortable
and safe (if not more so) in a 50 degree bank as in a 20 degree bank.

Marc


Agreed for feeling safe, but when comfortable is the question, I think
most pilots would find 1.02g is much more comfortable than 1.75g.
  #83  
Old August 27th 04, 08:29 PM
Mike Lindsay
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I must say, however, that I vaguely recall that other countries don't
fly rectangles, but a V and then a 45 deg turn onto final.
Is this true? It seems like a better way to avoid looking
back over the shoulder for the touchdown spot...


--

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


Not in this country (UK). But I was taught to do a 45 degree approach at
Minden.

--
Mike Lindsay
  #84  
Old August 27th 04, 08:43 PM
Mike Lindsay
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In article [email protected]_s04, Bill Daniels
writes

Most of us pretty well know the routes we will use on XC flying. Get your
handheld GPS, a digital camera and a good map with a Lat/Long grid and go
driving. Looking over fields from ground level is much better than from
1000' feet while stressed out.

You don't need to find many fields, just enough to fill in the gaps between
airports. When you find a good one, note the GPS coordinates and take
photos and notes. Maybe include the name of the landowner and a phone
number. If you can, walk the landing area. Then, post them on your club
web site. The Albuquerque Soaring Club is a good example of this.

Scratching for a save when within an easy glide of a known safe landing site
is a lot less stressful.

Bill Daniels


Excellent idea. But the trouble is, what might be a good field in August
2004 might be terrible in June 2005, with a rape or potato crop..
--
Mike Lindsay
  #85  
Old August 27th 04, 10:38 PM
Mark James Boyd
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Kirk Stant wrote:

1) If they ain't locked for takeoff, a gnarly pio


1. Use a checklist. Oh, and why is the tow pilot fanning his rudder
at me?


LOL! "use a checklist."
Kind of covers everything, huh?

"Oh yeah? He had an accident? I bet he
didn't use the checklist!"

everyone nods solemnly in agreement, and the
speaker passes Leadership 101 for saying the most obvious,
non-controversial thing anyone can think of

ROFL! Man, I remember my MEI and his checklists.
We added so much stuff, I think there was
something about taking our pulse and blood pressure
in the runup to ensure we weren't overstressed
for the flight. Oh, and zipper check and
make sure we had chewing gum in case ATC gave us a
real fast descent. I think we had to taxi back for
fuel one time because we'd drained the tanks in
the runup area doing the checklist.

But hey, Kirk, I'm just teasin ya'. Just one of my
pet peeves, the checklist with the important
points buried.

How about just three critical safety items in the PW-5:

1. Airbrakes locked
2. Trim forward
3. Belts on tight

I'm a big fan of the prioritized checklist.
Do the three most important items first.
Do the nine most important items next.
Do the 27 most important items next.
Do the 81 most important items next.
And so on...

To figure out what the priority list should be, I
follow this advice:

You should learn from the mistakes of others, because you?ll
never have enough time to make all those mistakes yourself.
--- Ben Franklin

So I scour the accident reports, and see what killed
other pilots, and put that at the top three. Then I see
what caused non-fatal accidents, and put that in the
next 6-9. Then I add in the stuff from the
factory checklist. Then I add the piddly stuff that just
prevents a nuisance (vent closed to avoid dust, for example,
or towrope attached. It's hard for me to imagine why
an unattached towrope would be a safety hazard

Despite my best efforts, I've found myself getting sleepy
after the 45th item on the checklist. So this has worked
best for me.
--

------------+
Mark Boyd
Avenal, California, USA
  #86  
Old August 28th 04, 12:13 AM
ADP
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That means that the NTSB can add to the accident report:
1. Failed to use proper check list.

Along with my favorite:
2. The aircraft had not filed a flight plan.

As in: A sharp wind blew up and destroyed the properly secured glider
while the operator was home in bed. The operator had NOT filed a flight
plan.

The NTSB finds the probable cause to be the Pilot's failure to use a proper
check list and file a flight plan. Contributing factors were the 100 knot
wind and the fact that the pilot was home in bed at the time of the
accident.

Allan

"Mark James Boyd" wrote in message
news:[email protected]
Kirk Stant wrote:

1) If they ain't locked for takeoff, a gnarly pio


1. Use a checklist. Oh, and why is the tow pilot fanning his rudder
at me?


LOL! "use a checklist."
Kind of covers everything, huh?

... Snip ...



  #87  
Old August 28th 04, 12:20 AM
Bruce Hoult
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In article ,
Robert Ehrlich wrote:

Well, I disagree, and I strongly believe that a well-trained glider
pilot, in any glider, low or high, should be every bit as comfortable
and safe (if not more so) in a 50 degree bank as in a 20 degree bank.

Marc


Agreed for feeling safe, but when comfortable is the question, I think
most pilots would find 1.02g is much more comfortable than 1.75g.


That's 1.06 vs 1.56, actually.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------
  #88  
Old August 28th 04, 04:06 PM
Chris OCallaghan
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Andy,

I guess my only comment is a question: Does it really make any
difference in what you see? Framing wires against the sky (if that's
your intent) requires being lower than the wires. Which in turn means
you are at risk of hitting other wires.

What is the genesis of this approach? It clearly requires advanced
energy management skills, so it isn't appropriate for low time pilots
(the majority) or lower peformance sailplanes. Was it suggested by
someone, or is it someplace you arrived through time and experience?

I'll give it a try at the home drome during my next few flights. But I
guess I'm still having trouble determining what advantage I have by
flying a base and final leg low and fast. Would you apply the same
method for an approach over tall trees? Even if it meant losing sight
of your intended touch down point during much of the final leg?

As an aside, I'll suggest that best way to avoid wires is to land in
the very center of the biggest appropriately textured field you can
find. If the field is more than 500 feet wide and you see no poles,
you'll find no wires (unless of course, they're marked on your
sectional!). Alas, we can't get farmers to grow turf in such
proportions in appropriately spaced fields.
  #89  
Old August 28th 04, 04:31 PM
Chris OCallaghan
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Marc,

Per earlier discussions, the spin is avoided by coordinating rudder
with aileron input. The stall is avoided by decreasing angle of
attack. Yes, aileron input will increase angle of attack at the tip,
but in modern sailplanes, if you use an equal deflection of rudder,
even on the cusp of a stall, a certified aircraft will not spin. Of
course, this ignores other variables, and there's nothing like a few
extra knots (read lower AOA) to keep things manageable. But we really
should start discarding some of the old axioms. Or at least replacing
them with more accurate ones.

Let me give you an example for the sake of continuing the discussion
on an interesting tangent. You are very close to the ground, turning
base to very short final. In a twenty degree bank, you sense your
speed has decreased and your bank is suddenly steepening. You fear
that your wingtip will touch the tree tops before completing the turn.
What do you do?

Think this one through. According to an axiomatic approach, you make
no aileron input because your fear entering a spin (or your muscle
memory keeps you from doing it). Lowering your angle of attack means a
momentary increase in sink rate. Kicking the rudder exclusively will
also increase your sink rate, even if manages to slow or stop your
roll momentarily.

There's only one effective solution.

Maybe we should spawn a new thread.

Cheers,

Chris
  #90  
Old August 29th 04, 12:01 AM
Mark James Boyd
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ADP wrote:
1. Failed to use proper check list.
2. The aircraft had not filed a flight plan.


3. Pilot failed to maintain proper terrain clearance.

everyone nods heads solemnly in agreement with
the wise sage who figured this one out too
--

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




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