Dear Burt

At 17:00 04 February 2005, Jim Vincent wrote:
³In reality ailerons and the rudder don¹t turn airplanes;
they allow the
pilot to bank the airplane, allowing the engine to
pull the aircraft around
in a circle. Once the turn is established, controls
are returned to almost
neutral and the elevators and engine do the work of
turning the airplane.²

Hmmm, I wonder what makes a glider turn. Maybe only
motor gliders can turn
and then only after the engine is started.

Lift is what causes an airplane or glider to turn.
Bank the wings and a
component of lift is then in the horizontal, causing
the turn. All the engine
does is control the rate of climb, typically to maintain
altitude.

Jim Vincent

Seems to me this picture is also inadequate. If the
aircraft is banked and a component of the lift is then
horizontal, why doesn't the aircraft just go sideways
over into the next county?

We need a good mental picture of what is happening
to cause the circling flight instead of just being
lifted sideways. We have to bring gravity, centrifugal
force, and the effect of the tail feathers into this
picture.

"Nyal Williams" wrote in message
...
At 17:00 04 February 2005, Jim Vincent wrote:
Seems to me this picture is also inadequate. If the
aircraft is banked and a component of the lift is then
horizontal, why doesn't the aircraft just go sideways
over into the next county?

We need a good mental picture of what is happening
to cause the circling flight instead of just being
lifted sideways. We have to bring gravity, centrifugal
force, and the effect of the tail feathers into this
picture.

You need to remember that this is a 3D vector problem involving both
velocity vectors and acceleration vectors.

The math works out something like this:

Turn Radius = Velocity squared divided by 11.26 time the tangent of the bank
angle.
Velocity is in knots (TAS), bank angle is in degrees and turn radius is in
feet.

The full description of the problem and its' solution can be found on page
178 of the 1965 edition of "Aerodynamics for Naval Aviators."

Respectfully,

Wayne
http://www.soaridaho.com/Schreder

This is exactly my point! Why don't we all already know what makes an
aircraft turn? Many pilots feel they do, but if we sit several
professional pilots down, separately, and ask them how an aircraft
flies from a pilot's perspective, you'll get three substantively
related, though specifically different answers.

I can demonstrate with an equation (F=ma), a rectangular piece of stiff
paper, and a paper clip that an aircraft in a bank will turn (establish
a circular flight path) unless the pilot intentionally prevents it from
turning by applying rudder or reducing AoA. The point, for the sake of
this thread, isn't to define a theory of flight suitable for aviators.
Rather, it is to recognize how informal and untested many of our
theories really are. A theory that demands tail feathers to initiate
turns (as opposed to the wing just dragging the aircraft sideways
through the air) doesn't sufficiently explain the flight of hang
gliders, boomerangs, frisbees, or my paper clip ballasted flying wing.

Some might say, well, the model serves well enough.... but does it
really? How many accidents do we have each year that are preventable?
Why do competent pilots spin in? Why do well-trained pilots demonstrate
a lack of competency in basic flight skills like slipping and stall
recognition?

I'll return to slips: it's my favorite example becasue so few people
can do them well or describe them accurately. What factors need to be
considered during a slip? Are you aware that the ailorons contribute a
nose down pitching motion during a slip? Have you considered that
during a slip, you must increase the angle of attack because the lift
verctor is no longer antiparallel with graivity (as in a turn)? Are
you aware that the pitching moment of the elevator decreases with
increased beta? What effect on lift and drag does the effective
reduction of wing aspect ratio have? What differences in stick use can
be expected in a high performance versus a wide-body glider during
slipping? Is there any aerodynamic difference between a forward and a
side slip? If there isn't, why do we bother differentiating them? Have
you ever seen any of these ideas discussed in a flight primer? Why not?
I consider all these questions foundational. Yet it took me a long time
to start asking them. I learned to do slips by rote, but never did them
really well until I began to ask these questions. Hopefully, you'll
recognize I've only asked some of the less obvious questions. There are
plenty of others, some taught, some ignored, some simply not
recognized. An example of the latter... how do you measure airspeed in
a slip?

OK, I'm dancing on the head of pin, but I needed an example to drive
home what we don't know about something so "simple" as slipping. A good
pilot should be asking questions and looking for answers all the time.
A good instructor should be looking for new and better ways to pose and
answer such questions. One last example, if I asked "What is the
primary yaw control in a glider?" how would you react if I answered,
"its the ailerons?" And why might this be a better answer than "the
rudder?"

There's alot left to learn, and discuss, and apply. And alot of bright,
"mis-informed" people out there who have something to contribute. I'll
address myself to Burt again... if the RAS is misinformed, isn't the
source culpable? Isn't the first step to recognize that we're ALL, to a
greater or lesser degree, misinformed so we can get about the business
of improving our understanding?

Not to be argumentative without cause...but in my humble opinion you are
very caught up in the minutae or degree of specificity as though you have
the only way...I guess that my point. There are many ways to discuss these
and a myriad of issues and the real key is to convey the information to a
student so that HE/SHE understands the principles...Just when I start
thinking I really know my stuff about aerodynamics, I listen to someone like
Mark Maughmer...or some other guy who REALLY knows his stuff...and all the
blacks and whites start turning grey...


I guess my analogy would be...that I really don't completely understand the
funky new "low volume flushing toilet" to an exacting tolerance, but I've
never had difficulty understanding it's theory of operation, or using it, in
its intended roll.

My opinion would be that we should speak simple english, that new guys can
understand and make certain that we've conveyed the correct principles and
answered questions in logical fashions...And demonstrated behaviors that are
consistent across the board. I've had lots of check rides and bi-ennial's
and NEVER...NOT ONCE....do you answer every question to the satisfaction of
the examiner/instructor. Not to worry though...the trick is in making sure
that the student or examinee understands well, and has the tools required to
accomplish the task at hand.


That's it from me...


Steve.

Steve, don't run away...

You're going in an interesting direction and raising interesting
questions. I think I'd like to see wrangle through just what
information needs to be conveyed? I can speak simple English and
present you with a model that is patently wrong, but applicable. And
that's my point: what's the right model?

What's fascinating about where we're going with this discussion is that
we don't have much latitude for experimentation. If we go down the
wrong path, it could cost dearly. But at the same time, the methods we
currently use demand some healthy suspicion.

As for my commitment to a "way," that is, my way... of course I'm
committed to it. This is a potentially dangerous business we pursue,
and we need to have confidence in our abilities to see every flight
through to a successful outcome. As an instructor, I had some axioms,
among them that a student who could not demonstrate control of the
glider had absolutely no business flying alone in it: the basis for my
criticism of your "flexibility." However, that doesn't mean I'm not
open to differing view points. Just be ready for a bit of sparring. I
am, if nothing else, open to having my mind changed. If we were talking
Marxist criticism of Shakespeare, I might be more disposed to wear your
opinion... but when it comes to flying, you'll have to make a sound
argument and skillfully field my objections.

I mean this to be entertaining. A little sparring. A little learning,
for both of us.

wrote:
What's fascinating about where we're going with this discussion is
that
we don't have much latitude for experimentation. If we go down the
wrong path, it could cost dearly. But at the same time, the methods
we
currently use demand some healthy suspicion.

================================================= ====================

Earlier I made two examples that I thought detailed some of the more
pressing problems in instruction today: lack of detailed ground
instruction on a conceptual basis, and a specific example of how that
translated a short-handed description into a bad understanding for a
student (in that particular case a new PPG).

Pilots like to fly, otherwise they would do something else. Some
instructors are very good pilots, yet they are not particularly good at
communicating on a conceptual level the art of flying. Result, a
flying instuctor that hangs onto the stick and is always willing to
show instead of teach.

New instructors are particulary susceptable to this as they are not
quite sure of their ability to let out enough rope to the student but
not so much as to hang themselves as well. So they hang on. Some very
experienced pilots do just that. When I had one flying me around while
I was being checked out in the club's grob, I suddenly realized that I
was probably doing the same and wasn't even aware of it. Speak more,
show less.

Which brings out another frequently overlooked item. An aircraft is a
lousy classroom. In a tandem configuration, I am talking to the back
of someone's head. If we accept that a great portion of communication
is non verbal, then students are only receiving a small portion of what
is trying to be conveyed verbally.

It is more fun to fly. I would rather strap into the glider and fly
flight after flight, but were I to do that with students, how would I
plan, brief, clarify questions, query, and evaluate progress for that
day while examining my student's hat or hair style? Impossible.

The instructor sets the plan and executes the instruction. By taking
the time, and it does take AT LEAST the same amount of ground time as
flight time to settle any misconceptions and solidify instruction, your
student will have fewer bad habits and hopefully fewer withdrawls from
the bank of luck.

Terry

I am a Private SEL and Glider Pilot, not an instructor or an examiner,
so go easy if I have no biz contributing!

I currently work at an airplane flight school (not as a pilot). I have
observed how individual students/customers learn and progress, each in
their own timeframe and each with his/her own strengths and weaknesses.
I've also witnessed how, with varying levels of success, the CFIs
perceive and handle customers' differences.

Based on those observations and my own personal experiences, I have two
comments:

(1) "One picture is worth a thousand words." Terry, I appreciate the
value of your thoughts about how "the student needs to learn, not me"
and about being able to "fly orally, and certainly there are some things
that can only be explained or shown to a point, after which the rest is
up to the student/customer. On the other hand, while some CFIs are
hesitant or even reluctant to "fly for the student", there are other
times when being SHOWN *instantly* teaches an understanding that
multiple verbal or written descriptions cannot convey. The preached
phrase -- "don't fly on the customer's dime" -- has been taken so
literally and absolutely by some instructors that repeatedly and
unsuccessfully verbally explaining something vs. demonstrating it
sometimes wastes more of the customer's dime than it saves.

(2) Please welcome questions, and never EVER make anyone regret asking
you. I know how BASIC that is, but it addresses the original ideas about
erroneous info on RAS or anywhere, how and why it is born, how long it
lives, and whether or not instruction is lacking. Whether we hear it in
a hangar caf or read it on RAS, if it gets people thinking about
specific areas, and more importantly, if we bring the thought/question
to you, a CFI or Examiner, *THAT DISCUSSION*, regardless of the source
that prompted it, should be one of the most welcome opportunities you
get to further educate us.

I have tremendous respect and gratitude for everyone I've taken
instruction from, but I have varying levels of comfort approaching each
of them with questions. I have been both chastized and applauded for
asking questions that originated from discussions on the internet. In
one instance, Instructor-A blasted me for even considering that anything
I'd read on an internet newsgroup may have validity; Instructor-B heard
my question, suggested some topic-specific reading material, and took a
flight with me to address the subject hands-on. Which instructor made me
feel apprehensive about asking other questions? And which reaction to my
question was advantageous to me as a pilot constantly striving to be as
safe, knowledgeable and competent as possible?

Lastly, I recently was invited to sit-in at a CFI meeting. During an
exchange of ideas/suggestions for various areas of instruction, one CFI
expressed a preference for teaching instrument or commercial students
because "they already know how to fly." Another instantly spoke up,
saying that she welcomes and appreciates the opportunity to teach
private students because she's had so many instrument and commercial
students that have clearly been adequately taught the mechanics of
flying, but NOT how to think, reason and make sound judgments in
situations that aren't routinely rehearsed for a checkride. She said she
felt that skill of how to think, due to the vagueness of how to
measure/grade it, was the one most commonly skimmed over and
consequently lacking, and sometimes not received as well when addressed
in a person already licensed vs during training for Private.

Interesting thread. Thanks!

Don't sweat it...no running here.

I am simply convinced that many times, one persons perfect plan, is another
persons last alternative.

I think what we are really referring to, is the single most difficult thing
to teach. we can teach the skills, we can teach the theory, but what we
cannotn teach, is judgment. The first time you cut a student loose, after
knowing they have all the required skills and then you watch them do
something truly dumb or completely adverse to what you've taught, you
realize that the single best thing we can try to share, is how to think and
analyze and act. There was an old military adage called the ODA loop. I'm
sure someone will be able to tell you the guys name. It was
Observe,Decide,Act. It really became and analytical basis for modern
warfare. As Mark James Boyd points out, the PTS does a good job of laying
out what is to be demonstrated to the minimum acceptable standards. I have
just always sorta felt that the PTS and ensuing exam is based on passing the
test in a 2-33 and going for 20 minute sled rides.

Real world in a 45:1 sailplane...that test doesn't even scratch the surface
of what's required.

We can argue for weeks I'm sure and in the end, a free exchange of soaring
philosophy from a variety of sources is of more benefit to a soaring pilot
advancing into the ranks, then just passing the FAA Knowledge Test and PTS.
Just my opinion...flame me all you want. Not a safe soaring pilot, does a
freshly printed Glider certificate in hand...necessarily make.


I'm still not running....but it is Friday and I'd rather go have a beer than
argue anymore.



Steve.

Glad I misunderstood. I'd have joined you, but Laura had beer and pizza
waiting this evening.

Cheers,

OC (hic)

In article ,
Steve Hill wrote:

I have
just always sorta felt that the PTS and ensuing exam is based on passing the
test in a 2-33 and going for 20 minute sled rides.

Real world in a 45:1 sailplane...that test doesn't even scratch the surface
of what's required.

You may be correct about the test. OTOH, if people are flying things
similar to what they've lerared in then they are probably OK. At our
club, at the moment people learn in 38:1 sailplanes, but in 18 months or
so we'll be switching to 45:1 sailplanes from their first flight.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------