Glider Tail Stall

Glad to see people Dog-piling on me and exagerating my comments...
*smirk* Makes me wonder why are you folks feeling so threatened and
defensive. I'm not advocating a college course in order to get your
pilot's license, I'm not calling for any changes at all in my
comments... Why are folks blowing this out of proportion?

Please re-read my original post carefully. I never said you had to
have a "perfect" understanding of aerodynamics. I also never said it
would make you a fast race pilot. I'm saying that pilots should
understand what is happening - aerodynamically speaking - when they
deflect the control surfaces on their aircraft.

The sum total of your knowledge should not be "I push the stick to the
right to make the airplane roll right". It should be "I push the
stick to the right which makes the left wing aileron go down,
increasing angle of attack and therefore the lift on that part of the
wing. Simultaneously, the right wing aileron is doing the opposite
movement with the opposite effect. The net _effect_ is that the
aircraft rolls toward the right - with a bit of adverse yaw because
the increased lift on the left wing has a bit of rearward action/angle
on it."

And since people are taking me so literally, let me clarify that I'm
not advocating you talk through this whole sequence with each control
movement - but it _should_ be something you intuitively know is
happening. In a cause-and-effect system like flying, you need to
understand the "cause" bit - because the "effect" is only guaranteed
under certain limited conditions.

What I am claiming, is that knowing this stuff will make you a better
pilot and perhaps a more consistent pilot. Most of all it will make
you a safer pilot. As Bob Wander is fond of saying, "your aircraft is
your life support system". I think its mind-boggling that people are
willing to use a life-support system they don't understand.

Regarding the sarcastic "National Team" comments: I'm working on
that. :-) I've only been flying for 2 years (well, 2.5 if you count
powered aircraft as "flying"). I will be competing in my first
Regionals here in late April at Warner Springs. Last summer I bought
a DG-300 and took my first 7 flights out of an unfamiliar airport
(Ephrata). I made 3 flights in excess of 400km (at 82 - 97km/hr); and
all 7 flights were in excess of 200km - even the first couple of
familiarization flights and on days with OD and rain.

I'll let this die now - I'm sure many of you will post follow-on
comments that will tempt me to jump back in and clarify - but I'll try
to resist. If you're dead set on arguing this, nothing I say will
change your mind - so I'll try not to waste everyone's time.

--Noel

On Feb 24, 3:36 pm, "noel.wade" wrote:
Glad to see people Dog-piling on me and exagerating my comments...
*smirk* Makes me wonder why are you folks feeling so threatened and
defensive. I'm not advocating a college course in order to get your
pilot's license, I'm not calling for any changes at all in my
comments... Why are folks blowing this out of proportion?
....

--Noel

Noel,

Maybe are responding to the tone of this post by you:

2) I continue to be astounded by the pilots out there who are
perfectly happy to GAMBLE THEIR LIVES by taking part in an activity
where they don't know what it is they're doing; AND they will even
state outright that they don't CARE that they don't know (like some of
the people who said so in this thread)!!

After they had stated reasonable positions on how much aerodynamic
knowledge is needed during flight. So don't be suprised that people
kick back.

Todd Smith
3S

It is impossible to separate the aerodynamics that you learn from the books
from the total learning experience putting things you learned in the book
together with things you learned from your Instructor. The total package is
what makes us better pilots. I know that if you get into a spin because of
a bad turn from base to final, you are not going to have time to decide,
'did my tail stall' or what. I think this topic got started when the video
came out about the videos about icing causing a tail to abruptly go down
when the area of stagnant air moved back to the rear of the stabilizer.
This caused a movement that is not expected and the response has to be a
learned not an instinctive one from regular 'stall' warning signs. You have
to have the whole package of book facts and mechanical skills learned in the
cockpit to make a safe pilot.
"Eric Greenwell" wrote in message
...
Andy wrote:
On Feb 24, 1:00 am, Jim White wrote:
Does anyone else see the connection? I don't.

I don't claim any expertise in aerodymanics but I have never felt that
it placed any limitation on my ability as a pilot. With a perfect
knowledge of aerodynamics and a full understanding of the
characteristics of the glider being flown, all pilots still lack
complete knowledge of the airmass they are flying in. How can the
aero solution be derived without a knowledge of the airmass behavior?

I very much doubt there is a good correlation between pilot
proficiency, particularly cross country flying skills, and the
theoretical knowledge of aerodynamics. If I'm wrong we should see
Noel in the National team quite soon.

I have to agree with Andy. I've flown gliders for 33 years, 6000 hours
(5500 cross-country hours), and instructed for about 12 years. I am geeky
to the point of annoyance about aerodynamics (I'm sure pilots around the
world hesitate over the "send" button because they are afraid I will whip
out my "Fundamentals of Sailplane Design" and ruin a good argument). And
yet, I can't really think of how my knowledge of aerodynamics has kept me
safe all these years.

Same for my students. Sure, we talked about aerodynamics, but it was to
reinforce the lesson or to satisfy curiosity, not to equip them to deal
with a flight problem (literally) "on-the-fly".

And frankly, most of us have such a simplistic understanding of
aerodynamics, it's probably best we don't try to use it to deal with a
flight situation. Shoot, we still have discussions about which way the
elevator is 'lifting', yet pilots aren't crashing because they don't know
the right answer.

I'd like to hear of examples where a knowledge of aerodynamics saved the
day. I don't have any I can recall, but maybe someone's comments will jog
my memory.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Many thanks to those that supported my argument. My reaction was indeed
against the SHOUTED proposition that I was a dangerous numb head because I
felt that a knowledge of aerodynamics was not fundamental to my flight
safety.

Noel, seems I have an edge on you. I have been flying 15 years and have
flown in 7 UK Nationals competitions, sometimes doing quite well. I
suspect that when you have built up some experience you may temper your
assertions.

Jim

Argh, so much for my resisting a follow-up:

1) I need to apologize. My flight experience may be small, but my
computer experience stretches back to age 6, long before there was an
"internet". In the good old days of dial-up modems (300 baud, baby)
it was common to use ALL CAPS as a replacement for bold text, and
_underscores_ to indicate italics. The "CAPS is SHOUTING" standard
evolved later (sometime in the late 80's if I recall correctly). I
understand it, and hate shouting as much as everyone. But I still
sometimes slip back into all caps when I'm trying to really stress
certain words or make things stand out. My intent was not to yell
_at_ people, but rather to raise my voice in disbelief that people
don't see (or care about) the connection between their understanding
of how air flows over their aircraft and how it affects their safety.
The whole "lack of vocal inflection in typed communications" thing
still rears up and bites us all from time to time.

2) One last time (and I promise, it really is the last time in this
thread I'll post): I think people took my initial comments too far.
My main point is that I see too many pilots talking (and worse, too
many instructors teaching students) about moving the controls and how
the aircraft reacts. And the connection to aerodynamics is lost.
Sure, people read in a textbook about lift, drag, and gravity. And
they see a pretty picture about angle of attack. But then once they
take the FAA written test, the knowledge falls out of their brain and
they never think about it again. The thing is (and this is my central
point) - the aircraft doesn't _care_ what you do with the controls or
what the textbook says. The aircraft is going to react to what the
air around it is doing; and the controls are just a means to
manipulate that airflow (and only to a limited extent). However good
or however safe a pilot may be, I personally believe they could be
even _better_ if they keep that rattling around in the back of their
brain. Not thinking through every step or any calculations; but just
the general ideas and concepts and an understanding of how it all
works. And I believe a pilot who doesn't have this knowledge and
doesn't think about this stuff is at a much greater risk of reacting
improperly in an emergency situation (or unintentionally doing
something that increases their risk-factor during a flight).

Alright, I promise I'll really let the thread die now... :-P

--Noel
P.S. Jim - just a note about experience: I flew R/C gliders for a
few years before going "full-scale". My favorite thing was to fly 24"
wingspan flying wings on small hills (20 - 30 feet tall) using ridge/
slope lift. The total CG envelope was 1/8th of an inch in size, and
total movement of the control surface was about 3 millimeters (full
back-stick to full forward-stick). And we flew 1 - 2 feet off the
deck a lot of the time... Its different from flying full-scale stuff,
but it really trains the hands and makes the pilot focus! ;-)