Gliding lecture slides

On Apr 14, 10:18*am, (Richard Lancaster)
wrote:
Hi,

I've put some lecture slides on the following topics:

* Principles of glider flight
* Glider instruments

onto the web site:

http://www.carrotworks.com/

Regards,

Richard

Generally excellent for an introductory presentation. There are a few
very minor issues that only an engineer or aerodynamisist would
catch. One is the use of the Greek letter Alpha to label the AoA of
the fin in a skid - Beta is correct.

Another is the description of the secondary effect of roll with the
application of yaw inputs (Yaw to roll coupling). You are correct
that this is momentarily due to a spanwise difference in airspeed but
you failed to mention that the continued, and much larger, effect is
due to dihedral. Your description of 'adverse' yaw is correct but I
cringe at the negative connotation of the word. Adverse yaw is not
"bad" yaw - it's just what ailerons do. In fact, 'adverse' yaw can be
quite useful in soaring turns as well as in crosswind landings.

BTW, your description of how lift is generated is just fine for this
sort of presentation. Some will argue endlessly about it without
reaching a consensus but yours is more than good enough.

On Apr 14, 1:24*pm, bildan wrote:
On Apr 14, 10:18*am, (Richard Lancaster)
wrote:

Hi,

I've put some lecture slides on the following topics:

* Principles of glider flight
* Glider instruments

onto the web site:

http://www.carrotworks.com/

Regards,

Richard

Generally excellent for an introductory presentation. *There are a few
very minor issues that only an engineer or aerodynamisist would
catch. *One is the use of the Greek letter Alpha to label the AoA of
the fin in a skid - Beta is correct.

Another is the description of the secondary effect of roll with the
application of yaw inputs (Yaw to roll coupling). *You are correct
that this is momentarily due to a spanwise difference in airspeed but
you failed to mention that the continued, and much larger, effect is
due to dihedral. *Your description of 'adverse' yaw is correct but I
cringe at the negative connotation of the word. *Adverse yaw is not
"bad" yaw - it's just what ailerons do. *In fact, 'adverse' yaw can be
quite useful in soaring turns as well as in crosswind landings.

BTW, your description of how lift is generated is just fine for this
sort of presentation. *Some will argue endlessly about it without
reaching a consensus but yours is more than good enough.

I was maybe a little imprecise in my niggle, but Kevin has described
it very well. My main criticism would be that glider pilots don't
really need to know this. The rest of the stuff is fine.

Mike

Mike the Strike wrote:
... There are a few
very minor issues that only an engineer or aerodynamisist would
catch. One is the use of the Greek letter Alpha to label the AoA of
the fin in a skid - Beta is correct....
Mike

Hmmm...beta is yaw angle, and alpha is AoA.
In referring to side forces generated by a vertical fin,
beta is not quite the controlling factor, is it, when the rudder effect
is included?

Brian W

On Apr 15, 8:24*am, bildan wrote:
One is the use of the Greek letter Alpha to label the AoA of
the fin in a skid - Beta is correct.

In mathematics variable names are without meaning and therefore
interchangeable, so I don't see how you can say that a particular
labeling is correct or incorrect, but at most that it follow or does
not follow some convention.

It is true that when considering an entire aircraft it is conventional
to use Beta for yaw, but if you are considering the fin as an airfoil
in isolation then Alpha is perfectly reasonable in order to use the
same equations as you would for other airfoils.

Thanks for the comments.

You wouldn't believe how much time I spent on the first few slides of the
Lift / Drag lecture, the bit covering how a wing generates lift, to try to
make them benign with respect to controversy but still say something
useful and meaningful.

Kevin, when I get a chance I will go back and review the streamline and
force diagrams on pages 7 and 8 of the Lift / Drag lecture. It does look
like they might be slightly erroneous, but I just want to check back
through the literature and dig out some experimental results before I make
any changes.

Bildan, with regard to yaw generating roll via dihedral effects I do
actually say that in the slide. However the section on the effects of the
controls is going to get a rework at some point. It's the only point in
all three lectures where the audience without fail zones out on you and
looses interest. So I need to think up some way of making it more
interesting.

Regards,

Richard

On Apr 16, 5:10*am, (Richard Lancaster)
wrote:
Thanks for the comments.

You wouldn't believe how much time I spent on the first few slides of the
Lift / Drag lecture, the bit covering how a wing generates lift, to try to
make them benign with respect to controversy but still say something
useful and meaningful.

Kevin, when I get a chance I will go back and review the streamline and
force diagrams on pages 7 and 8 of the Lift / Drag lecture. *It does look
like they might be slightly erroneous, but I just want to check back
through the literature and dig out some experimental results before I make
any changes.

Bildan, with regard to yaw generating roll via dihedral effects I do
actually say that in the slide. *However the section on the effects of the
controls is going to get a rework at some point. *It's the only point in
all three lectures where the audience without fail zones out on you and
looses interest. *So I need to think up some way of making it more
interesting.

Regards,

Richard

You're right, I seem to have missed the section on yaw to roll due to
dihedral. I apologize.

Just a thought. This isn't exactly fair - it's clear you spent a lot
of effort on the graphics - but just repeating the same graphics style
with minor changes with different text can be boring. There's an easy
way to illustrate slides and get more color and realism by using a
flight simulator like Condor. I think Uros would grant you the right
to use the graphics if you give full credit.

The flight sim technique is to set up a situation you want to
illustrate and pause the simulator at just the right moment. Select
the outside view you like then take a JPEG screenshot. The resulting
JPEG file can then be edited with a graphics or photo-editor to add
additional graphics or text. The result can be quite pleasing.