Spinning (mis)concepts

At 02:54 31 January 2004, Adp wrote:

Except it isnt is it! Gliders require you to understand
fully things like adverse yaw, energy management, not
being able to power-on and go around. When you land
a glider, you only get one shot at it, what ever the
conditions happen to be thrown at you. How much time
do you spend thinking of where you are going to land
out when you are at 1500 feet above the ground in
your power plane? It has nothing what ever to do with
irrational prejudice.

This is one of the biggest nonsense myths in the soaring
community. It
amounts to an irrational prejudice towards power pilots
who transition to
gliders.
There is considerably greater difference between, say,
flying a Bonanza and
flying a Boeing 757 than flying any glider.
Gliders are incredibly easy to fly. Simply be aware
of the differences.
It really amounts to attitude. (In both senses of
the word.)
When flying a Bonanza, think Bonanza. When flying
a King Air, think King
Air. When flying a B-757, think 757. When flying
a F18, think F18. When
flying a glider, think glider. When flying a motor
glider, think glider.
It can't be much simpler.

Allan

'Mark James Boyd' wrote in message
news:401acc7c$1@darkstar...
Pete Zeugma wrote:

Ah, power planes, not gliders! Do you not think perhaps
we should be differentiating between rudder usage
in
power plane, and a glider? I started flying originally
in gliders, so I dont have any bad habits from power
flying, and when I fly powered aircraft, i cant help
but fly coordinated all the time. I know that power
pilots who make the transition to gliders quite often
make fundemental errors due to the power mindset when
sat in a glider. What do you think?

Absolutely there are subtle differences that get overlooked.
Primacy is a factor here. Use of spoilers, wheel
brake
not at the feet, no stall horn, can't use throttle
to
descend, actually seeing adverse yaw, etc. All these
were probably much harder to learn (unlearn) than
if
one started as a glider pilot first.

....Snip....

It appears that you have missed my point - but managed to illustrate it very
nicely!
I rest my case.

Allan

"Pete Zeugma" wrote in message
...
At 02:54 31 January 2004, Adp wrote:

Except it isnt is it! Gliders require you to understand
fully things like adverse yaw, energy management, not
being able to power-on and go around. When you land
a glider, you only get one shot at it, what ever the
conditions happen to be thrown at you. How much time
do you spend thinking of where you are going to land
out when you are at 1500 feet above the ground in
your power plane? It has nothing what ever to do with
irrational prejudice.

This is one of the biggest nonsense myths in the soaring
community. It
amounts to an irrational prejudice towards power pilots
who transition to
gliders.
There is considerably greater difference between, say,
flying a Bonanza and
flying a Boeing 757 than flying any glider.
Gliders are incredibly easy to fly. Simply be aware
of the differences.
It really amounts to attitude. (In both senses of
the word.)
When flying a Bonanza, think Bonanza. When flying
a King Air, think King
Air. When flying a B-757, think 757. When flying
a F18, think F18. When
flying a glider, think glider. When flying a motor
glider, think glider.
It can't be much simpler.

Allan

'Mark James Boyd' wrote in message
news:401acc7c$1@darkstar...
Pete Zeugma wrote:

Ah, power planes, not gliders! Do you not think perhaps
we should be differentiating between rudder usage
in
power plane, and a glider? I started flying originally
in gliders, so I dont have any bad habits from power
flying, and when I fly powered aircraft, i cant help
but fly coordinated all the time. I know that power
pilots who make the transition to gliders quite often
make fundemental errors due to the power mindset when
sat in a glider. What do you think?

Absolutely there are subtle differences that get overlooked.
Primacy is a factor here. Use of spoilers, wheel
brake
not at the feet, no stall horn, can't use throttle
to
descend, actually seeing adverse yaw, etc. All these
were probably much harder to learn (unlearn) than
if
one started as a glider pilot first.

....Snip....

At 14:24 02 February 2004, Chris Ocallaghan wrote:
Pete,


Every now and then, I like to keep my hand in with
sidesliping on finals. One airfield I fly at has a
real narrow tarmac strip, like 5 meters. When I am
in a nice balanced, wings level sideslip, how come
I maintain a striaght path all the way down to my reference
point where I kick it off to round out?



Unfortunately, you are wrong on this one. You can,
in fact, use rudder to change direction, much to the
aerodynamicist's
chagrin.

especially if you have and engine up front.

It is very
inefficient, but by holding wings level and ruddering
(a skid)

side slip actually

you
create an inward pointing force caused by the fuselage
(along with a
rearward componenet -- drag). It is this force that
allows you to slip
by counteracting the turning force of the wing with
an opposite force
from the fuselage. (Again, much to the chagrin of the
aerodynamicist.)

Please, expand on this 'force', from an aerodynamics
point of veiw. I'd love to know what law of physics
you have created this thrust vector from.


You need rethink your model. Remember, things only
go straight if in
equilibrium.

actually, all objects in motion exhibit a natual tendancy
to go in a straight line, unless an external force
is applied to upset that equilibrium. One of Mr Newtons
laws I think!

An aircraft flying sideways through the air wings level
won't be in equilibrium, therefore either speed or
direction
must change.

I did loads of sideways flying this weekend soaring
on our hill!
Wings level, straight line constant 60knots, crabbing
along at 40 odd degrees.

in order to keep the wings level while applying yaw,
you have to apply a roll moment to counter the secondary
roll moment caused by the yaw. This puts the aircraft
back into equilibrium by force. If you release the
aileron, the secondary roll moment caused by the yaw
will eventually bank the aircraft into a turn. Stick
an engine into the equation, and it all changes.

Pete Zeugma skrev den 2 Feb 2004
15:16:31 GMT:
you
create an inward pointing force caused by the fuselage
(along with a
rearward componenet -- drag). It is this force that
allows you to slip
by counteracting the turning force of the wing with
an opposite force
from the fuselage. (Again, much to the chagrin of the
aerodynamicist.)

Please, expand on this 'force', from an aerodynamics
point of veiw. I'd love to know what law of physics
you have created this thrust vector from.

The same laws which keep you in the air, in fact. When the fuselage is
going through the air at a beta angle (sideslip), it generates lateral
lift. That's what makes knife edge flight possible.

Chances are this effect is not very noticeable in a glass bird with the
streamlined fuselage, meaning that the bank angle required to keep the
glider travelling in a straight path might be marginal and not really
noticeable.

Cheers,
Fred

On Mon, 2 Feb 2004 15:16:31 UTC, Pete Zeugma
wrote:


: you
: create an inward pointing force caused by the fuselage
: (along with a
: rearward componenet -- drag).

: Please, expand on this 'force', from an aerodynamics
: point of veiw. I'd love to know what law of physics
: you have created this thrust vector from.

May I jump in? He's right, and it's dead easy, really. If the fuselage
is yawed to the right, the airflow comes from the left. Which tends to
push the big front big - the cockpit - to the right. And I'm an
aerodynamicist, amongst other things.

: in order to keep the wings level while applying yaw,
: you have to apply a roll moment to counter the secondary
: roll moment caused by the yaw. This puts the aircraft
: back into equilibrium by force. If you release the
: aileron, the secondary roll moment caused by the yaw
: will eventually bank the aircraft into a turn.

Whoops. I think you are confusing the effects of yawing and the
effects of being yawed. As you yaw, one wing moves faster than the
other and produces more lift, tending to roll the glider unless
prevented. But once you are yawed, this effect ends. There may be
other effects requiring use of aileron while yawed - sweep forward in
the wings, for example.

: Stick
: an engine into the equation, and it all changes.

Not very much changes, actually.

Ian

Pete,

It sounds like you have the axioms down pat, but are having a little
trouble with recognizing that the controls allow pilots to do all
sorts of things that the designer didn't intend. Of course you can
(not should) rudder a glider wings level around a turn. Just like the
rudder on a boat. This is commonly called a skid.

Frankly, I can't tell whether you are trolling or exhibiting genuine
ignorance. Let's hope it is the latter -- there's a cure for what you
don't know. At any rate, I'd stop arguing on this point until you've
had a discussion with a CFI, power or sailplane. Your heart appears to
be in the right place. (It's the wings that turn an aiplane. The
rudder is to counteract adverse yaw.) But you're failing to recognize
how a pilot can abuse the controls to a variety of ends. Slips are
one. Skidding turns another. Stalls still another. Some are useful.
Some less so. Skidding turns fall into the second category.

At 10:00 04 February 2004, Adp wrote:
It appears that you have missed my point - but managed
to illustrate it very
nicely!
I rest my case.

Allan


Hardly, been busy and away from the office. Plus pilotnet
has been down the last couple days. This just fills
in my time between while waiting for software builds
to complie. Mind you, your theories on flight dynamics
have caused intence amusement here. several posts are
currently on our main notice board collecting comments
from within the flight dynamics group!

Well, not only have you missed my point but you have confused me with
someone else.
To what theories of flight dynamics are you referring?
I don't have any theories on flight dynamics.
It also seems that your "group" is starved for items of amusement.
My theory on spinning is simple - don't get into one and you won't have to
recover!
My point, to which you took exception, had to do with the thought that power
pilots
are deemed to be inferior to ab initio glider pilots when learning to fly
gliders and that
power training is of little use when transitioning to gliders.
Having run into this perception multiple times, I pointed out that it is
nonsense.
The few differences that define glider flying are small when compared to the
differences
between powered aircraft.
Aerodynamics are aerodynamics. They apply to gliders, powered aircraft,
buzz bombs and flat plates.
You just have to be aware of the differences.

Allan


"Pete Zeugma" wrote in message
...
At 10:00 04 February 2004, Adp wrote:
It appears that you have missed my point - but managed
to illustrate it very
nicely!
I rest my case.

Allan


Hardly, been busy and away from the office. Plus pilotnet
has been down the last couple days. This just fills
in my time between while waiting for software builds
to complie. Mind you, your theories on flight dynamics
have caused intence amusement here. several posts are
currently on our main notice board collecting comments
from within the flight dynamics group!

At 18:30 04 February 2004, Adp wrote:
My theory on spinning is simple - don't get into one
and you
won't have to recover!

strangly, thats basically what ive been saying all
along, and objecting to the 'experts' who insist its
ok to turn a glider using rudder alone!

My point, to which you took exception, had to do with
the
thought that power pilots are deemed to be inferior
to ab initio
glider pilots when learning to fly gliders

didnt mention ab initio at all, neither did i say they
were inferior.

and that power training is of little use when transitioning
to
gliders.

actually i said that there was a degree of unlearning
and bad habits that typically show up, in this particularly
instance the general theme was in the misuse of the
rudder pedals and the misguided belief that because
you can do something in a powered aircraft the same
must apply to gliders.

Having run into this perception multiple times, I pointed
out
that it is nonsense.

you may well think so in your own experiences, however
it still remains true. old habits are hard to break,
especially when they become instinctive.

The few differences that define glider flying are small
when
compared to the differences between powered aircraft.

and it is those small differences which when wrongly
applied to glider flight can rapidly end life!

Aerodynamics are aerodynamics. They apply to gliders,

powered aircraft, buzz bombs and flat plates.
You just have to be aware of the differences.

no argument there.

Pete Zeugma wrote in message ...
strangly, thats basically what ive been saying all
along, and objecting to the 'experts' who insist its
ok to turn a glider using rudder alone!


Pete,

No one in this group has suggested it is "OK to turn a glider using
rudder alone." In an earlier post you stated in no uncertain terms
that turning a glider with rudder only was an aerodynamic
impossiblity. You then "proved" your point by stating that unbalanced
movement of the rudder produces a forward slip. Is it surprising that
several of the group's readers, ones who lay hands on the controls
occasionally, took exception?

Your absolutism isn't uncommon. It is a tool used by good students to
learn and apply their lessons. It is especially common in flight
training, where instuctors must daily grapple with the fact that they
are giving their students access to an environment that capitalizes on
any lack of experience and exacts a brutal cost when it finds pilots
wanting. An axiomatic approach is warranted -- a short cut, proven to
be a fair trade between rapid progress to certification and safety in
the air. A pilot can even afford to arrest his development at this
point, but if you are going to engage in discussions on the philosophy
of flight, you'll need to start looking behind the short cuts your
flight instructor proffered to keep you safe in the air.

I assume your need for a strawman is a first step in overcoming
denial. That's a good thing. Get past this.