Magnus Effect

Well, after asking the question, I found most of what I wanted. Just a
matter of putting the right words into a search engine.

For those who care, see an excellent report at
http://www.grc.nasa.gov/WWW/K-12/airplane/cyl.html

The formulas for lift of a cylinder is specified. An example is given that
has a 20 foot long cylinder of 2 feet diameter. At 100 mph, 236 rpm
rotation of the cylinder yields 1085 lb lift.

That seems to answer the question, since the energy required to rotate a 2
foot diameter cylinder which is 20 feet long would be substantial. And,
this would not provide any forward motion - just lift. Much easier to use a
simple, less complicated wing. But, it might be possible to build something
that actually flew.

Now I am a bit smarter.

Colin N12HS


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"COLIN LAMB" wrote in message
nk.net...
...Has anyone every produced an airplane using the magnus effect? If the
cylinder is rotating faster, I would expect that lift would be increased.
Does anyone know if there have been any writings and/or test aircraft?

Doesn't count as a real aircraft, but a Magnus effect vehicle was theorized
in the 1957 juvenile science fiction book Tom Swift and his Ultrasonic
Cycloplane:

http://www.series.net/swift/volume10.html

In the late 1970s the Van Dusen Development Company built a
subscale prototype rigid airship which rotated to produce lift
via the Magnus effect. They never built a full scale vehicle.

-- Joe D.

Joe replied:

In the late 1970s the Van Dusen Development Company built a
subscale prototype rigid airship which rotated to produce lift
via the Magnus effect. They never built a full scale vehicle.

Well, Joe, now that you mention it, there was a full scale model that did
fly. I had forgotten about that. It was called the CycloCrane and used
helium to obtain neutral buoyancy then rotated using the Magnus Effect for
lift. During the experiments, it was stored in the old blimp hangers at
Tillamook, Oregon. I recall the last flight was in about 1991 when it broke
up.

So, there was an aircraft that used the Magnus Effect - sort of.

Colin N12HS




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COLIN LAMB wrote:
If a wing is replaced by a rotating cylinder, with the forward surface
rotating upward, lift will be produced. The local air velocity is high on
top and low on the bottom. This upward force is known as magnus effect.

The information above comes from my helicopter handbook. The theory is used
to explain some helicopter principles, but caused me to wonder more about
it. Has anyone every produced an airplane using the magnus effect? If the
cylinder is rotating faster, I would expect that lift would be increased.
Does anyone know if there have been any writings and/or test aircraft? Not
much use with a glider, for obvious reasons - but the answer would make me a
bit smarter. I was not able to find much on the internet.

Thanks, Colin N12HS


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It's possible to use the effect in an airplane, but
there is no concept of an angle of attack and the
L/D ratio is quite bad at low RPM.

You don't even neet an engine, the spin can be self-sustaining.
Experiment: Trow a strip of cardboard trough the air. If you get
it right, it will start to spin and glide at a L/D of about 1-2.

Regards,

Iwo

Iwo Mergler wrote:

It's possible to use the effect in an but
there is no concept of an angle of attack and the
L/D ratio is quite bad at low RPM.
...

The first thing (no concept of an angle of attack) is a good
reason that no airplane may have success using this effect.
An essential condition for an heavier than air aircraft to be
controlable is that its lift coefficient (CL) increases with the
angle of attack. So that if anything disturbs it from its previous
path by an upward deviation the angle of attack is decreased, and so
the CL and the lift (because the other factor, the speed, needs time
to change due to inertia), so the weight becomes higher than the
lift and this gets the aircraft back to its initial path, similar
things in case of a downward deviation. This is why airplanes and
gliders become uncontrolable at stall angle of attack, not by
lack of lift, the CL is then at its maximum, but due to the impossibility
of increasing it further by increasing the angle of attack.

"COLIN LAMB" wrote:
If a wing is replaced by a rotating cylinder, with the forward surface
rotating upward, lift will be produced. The local air velocity is high on
top and low on the bottom. This upward force is known as magnus effect.

Has anyone every produced an airplane using the magnus effect? If the
cylinder is rotating faster, I would expect that lift would be increased.
Does anyone know if there have been any writings and/or test aircraft? Not
much use with a glider, for obvious reasons - but the answer would make me a
bit smarter. I was not able to find much on the internet.

Thanks, Colin N12HS

Well, not so much "produced" as "used". No writings about it (until
now), but it will easily fly across the living room.

Take the thin walled cardboard tube from inside a roll of gift
wrapping paper. Hold it so it is sticking straight out from your
body, with your right hand below the tube, and your left hand above
the tube, palms to the tube. I know this sounds a bit perverted, but
stick with me. Now spin the tube by pulling your hands away from each
other and give the tube a toss away from you and to the right.
Careful ot to crush the tube! It may take some time to get a good
launch technique, but the tube will fly.

Gyroscopic effects and an unbalanced tube can make the flight path a
bit erratic. Tried end plates, as the basic tube has no directional
or lateral stability. That was a disaster! And it made launching
much more difficult. Good for minutes of fun. Terrorize the dog or
cat. Great for removing ornaments from Christmas Trees. Paper towel
rolls and toilet paper rolls don't work so well. Not enough aspect
ratio.

Tried to get Wham-O to package and sell them as a 21st Century
Frisbee. Eventually put the whole idea in the same place as the Slim
Whittman wrist watches that yodel every hour. ;-)

Steve Leonard

"Steve" wrote in message
om...

Take the thin walled cardboard tube from inside a roll of gift
wrapping paper..... Tried to get Wham-O to package and sell
them as a 21st Century Frisbee....

About 20 yrs ago, something similar was marketed as
a flying tube. It was essentially a 1/2 height aluminum soda can,
open on both ends. The lip on one end was slightly weighted.
You threw it like a football, overhand with a side spin. The
tube's open axis was the flight path. It flew very well,
would go 200 feet. It was amazing to see such a low mass object
cut through the air so far. Don't remember the name.

-- Joe D.

"Joe D." wrote:
About 20 yrs ago, something similar was marketed as
a flying tube. It was essentially a 1/2 height aluminum soda can,
open on both ends. The lip on one end was slightly weighted.
You threw it like a football, overhand with a side spin. The
tube's open axis was the flight path. It flew very well,
would go 200 feet. It was amazing to see such a low mass object
cut through the air so far. Don't remember the name.
-- Joe D.

There are similar things available now. But those fly along the axis
of the cylinder. The tube I am flying flies (sort of) perpendicular
to the axis of the cylinder.

Steve L.

On Wed, 20 Oct 2004 03:16:14 UTC, "COLIN LAMB"
wrote:

: If a wing is replaced by a rotating cylinder, with the forward surface
: rotating upward, lift will be produced. The local air velocity is high on
: top and low on the bottom. This upward force is known as magnus effect.

It's a simple illustration of the idea that vorticity/rotation
produces lift. Instead of inducing the rotation by the shape of the
section, you spin the cylinder and drag the air round with it.

: The information above comes from my helicopter handbook. The theory is used
: to explain some helicopter principles, but caused me to wonder more about
: it. Has anyone every produced an airplane using the magnus effect?

There's a shop in Covent Garden which sells magnus effect rotor-kites.
And you might like to look up the Flettner Rotor Ship, "Baden Baden"
(http://college.hmco.com/history/read...sh_009400_bade
nbaden.htm for example).

Ian

COLIN LAMB a écrit :
If a wing is replaced by a rotating cylinder, with the forward surface
rotating upward, lift will be produced. The local air velocity is high on
top and low on the bottom. This upward force is known as magnus effect.

The information above comes from my helicopter handbook. The theory is used
to explain some helicopter principles, but caused me to wonder more about
it. Has anyone every produced an airplane using the magnus effect? If the
cylinder is rotating faster, I would expect that lift would be increased.
Does anyone know if there have been any writings and/or test aircraft? Not
much use with a glider, for obvious reasons - but the answer would make me a
bit smarter. I was not able to find much on the internet.

No sailplanes, but a sailboat did navigate using rotary masts.

A similar effect is used on an helicopter instead of tail rotor (the
tail is not rotating but side lift is created from main rotor flow by
blowing air through on side or another )