On Feb 1, 2:30*am, Bertie the Bunyip wrote:
Dudley Henriques wrote :



Bertie the Bunyip wrote:
WingFlaps wrote in
news:ddef2011-7cca-4e5e-b5a8-
:

On Jan 31, 12:34 pm, "Robert M. Gary" wrote:
On Jan 30, 1:36 pm, Peter Clark

wrote:
For those interested in such things, the MythBusters show titled
"Airplane on a Conveyor Belt" is in TVGuide to air tonight at 9pm
Eastern US on Discovery/Discovery HD.
Yea, I had the TiVo searching for it for the last few weeks. I see
that its set to record soon (I never actually pay attention to when
a show is on anymore). I'm looking forward to it. To me the
interesting part will not be the experiment but the premise. Do
some believe that an airplane generates lift as a result of the
speed of the wheels? -Robert
I'd be interested in knowing whether they can detect the actual lift
derived from the wheels spinning as the plane lifts off...

Well, you could do it in a wind tunnel!
There was a time in the 30's when a rotating cylinder was seen as the
future of the wing. I think maybe even a few were built! I'm pretty
sure I have an old Popular aviation with a few pics of a fairly
unsucessful prototype..
But a little spinning wheel isn't going to give you much..

Bertie
Actually you can still do it.

Really? I thought there might have been a physics watershed back there
in the late ffties!

I used a spinning cylinder all the time
in my discussions on aerodynamics. It makes a perfect example when
getting into lift. A cylinder not rotating in a free stream airflow
has no lift as the stagnation points are neutral. The airstream flows
over the cylinder equally; no Bernoulli...no Newton.
Now spin the cylinder clockwise to the airstream. Walla......instant
lift! You get it all in one simple demonstration. You get upwash and
downwash. That's circulation. (Newton) You get increased local
velocity over the top of the cylinder and decreased local velocity
under it. That's Bernoulli!
The whole shegang is Magnus effect. It's a wonderful way to get into
wings, golf balls, curve balls...the whole magilla :-))

Excellent. What kind of contraption do you use to demonstrate?


You can do it nicely with a pencil, a piece of paper and elastic band.
Attach a strip of paper about 4" long and 1.5" wide at the narrow side
to the band with scotch tape. Then wind the paper around the middle of
the pencil and use the elastic band as a catapault. Get a helper to
hold one end of the band on a table, you the other end and pull the
pencil back along the table. Let the pencil go and as it flys across
the table it is also rotated fast. It leaves the table edge and
conducts one or two loops. A hex section pencil makes a nice noise
too. Only trouble is the lead gets trashed as the pencil hits the
floor ;-)

Cheers