Magnus Effect

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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Have not seen such an aircraft.. but the principle of the "magnus effect"
can be seen in the flight path of a golf ball... ever watch a golf ball when
first hit.. start out low and then increase the climb rate before arcing
over ?.. I'm not talking about a golf ball hit with a pitching wedge... but
hit with the driver.. the spin imparted is the same as the rotating cylinder
described.. creating "lift" over the top of the ball... and yes.. all those
little divots in the ball (I forget what they are called) adds to the
lifting effect.

BT

"COLIN LAMB" wrote in message
nk.net...
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


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
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Speak for your own balls! Golf balls that is. Mine don't climb progressively
in a straight line ahead but they do swing impressivelly left or right!

:-)

The divots are called dimples by the way!

Ian


"BTIZ" wrote in message
news:MKldd.32193$bk1.30147@fed1read05...
Have not seen such an aircraft.. but the principle of the "magnus effect"
can be seen in the flight path of a golf ball... ever watch a golf ball
when first hit.. start out low and then increase the climb rate before
arcing over ?.. I'm not talking about a golf ball hit with a pitching
wedge... but hit with the driver.. the spin imparted is the same as the
rotating cylinder described.. creating "lift" over the top of the ball...
and yes.. all those little divots in the ball (I forget what they are
called) adds to the lifting effect.

BT

"COLIN LAMB" wrote in message
nk.net...
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


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.775 / Virus Database: 522 - Release Date: 10/8/04

Ian... you are not hitting the ball "square on" but in a slice (across) the
desired flight path of the ball.. hence the hook or slice path of the ball..
instead of imparting an "over the top" spin, the ball is spinning off at an
angle, as in the earths axis is tilted..

roger on the dimples... mind froze up that late at night..

BT

"tango4" wrote in message
...
Speak for your own balls! Golf balls that is. Mine don't climb
progressively in a straight line ahead but they do swing impressivelly
left or right!

:-)

The divots are called dimples by the way!

Ian


"BTIZ" wrote in message
news:MKldd.32193$bk1.30147@fed1read05...
Have not seen such an aircraft.. but the principle of the "magnus effect"
can be seen in the flight path of a golf ball... ever watch a golf ball
when first hit.. start out low and then increase the climb rate before
arcing over ?.. I'm not talking about a golf ball hit with a pitching
wedge... but hit with the driver.. the spin imparted is the same as the
rotating cylinder described.. creating "lift" over the top of the ball...
and yes.. all those little divots in the ball (I forget what they are
called) adds to the lifting effect.

BT

"COLIN LAMB" wrote in message
nk.net...
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


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.775 / Virus Database: 522 - Release Date: 10/8/04

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.

News to me. I've been flying radio control helicopters and never heard of
this. Don't discredit me offhand, most full size rotor heads have no idea what
a pitch curve is or how many degrees they're pulling in fast foward flight
(FFF).

Generally what happens is that the rotor rotating forward generates more lift
because of relative wind. That generates a combined pitching and roll motion.
That rotation is around the vertical axis, the motion you're talking about is
about the lateral axis.

It seems to me that the magnus effect is best exampled by a spinning ball with
top spin, maybe like for golf or baseball. The lift contribution is generally
neglible.

Fire away! ;-)

Jim Vincent
N483SZ
illspam

I understand that that is the limiting factor to helicopter forward
speed.( and why 'Airwolf' could never have worked ) At around 400 kph the
forward going blade starts to overcome the amount of control input available
to overcome the rolling effect.

Ian

"Jim Vincent" wrote in message
...

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.

News to me. I've been flying radio control helicopters and never heard of
this. Don't discredit me offhand, most full size rotor heads have no idea
what
a pitch curve is or how many degrees they're pulling in fast foward flight
(FFF).

Generally what happens is that the rotor rotating forward generates more
lift
because of relative wind. That generates a combined pitching and roll
motion.
That rotation is around the vertical axis, the motion you're talking about
is
about the lateral axis.

It seems to me that the magnus effect is best exampled by a spinning ball
with
top spin, maybe like for golf or baseball. The lift contribution is
generally
neglible.

Fire away! ;-)

Jim Vincent
N483SZ
illspam

I understand that that is the limiting factor to helicopter forward
speed.( and why 'Airwolf' could never have worked ) At around 400 kph the
forward going blade starts to overcome the amount of control input available

I thought is was because the forward blade is approaching supersonic.

Jim Vincent
N483SZ
illspam

Could well be Jim. Like I said that was what I understood.

Ian
"Jim Vincent" wrote in message
...
I understand that that is the limiting factor to helicopter forward
speed.( and why 'Airwolf' could never have worked ) At around 400 kph the
forward going blade starts to overcome the amount of control input
available

I thought is was because the forward blade is approaching supersonic.

Jim Vincent
N483SZ
illspam

"Jim Vincent" wrote in message
...
I understand that that is the limiting factor to helicopter forward
speed.( and why 'Airwolf' could never have worked ) At around 400 kph the
forward going blade starts to overcome the amount of control input
available

I thought it was because the forward blade is approaching supersonic.

A one-off special version of the Westland Lynx has the record for
world's fastest conventional helicopter; it did 249 mph (401 kph),
albeit with special experimental rotor blades. Supersonic flow on the
advancing blade is a problem.

However a compound helicopter like the Lockheed Cheyenne AH-56
(stub wings and pusher prop in addition to main rotor blade)
or the XH-51A (pusher jet engine) could unload the main rotor and
do 250-300 mph.

I think the fictional Airwolf helicopter used pusher jets in
"supersonic" flight. IOW it was a compound helicopter, although
this wasn't clearly stated in the TV show. The Bell 222 it was modeled
on had stub wings for landing gear.

I don't know what the theoretical speed limit is for a compound
helicopter, but it's clearly faster than 400 kph.

But considering the difficulty of getting a winged plane to efficiently fly
supersonic, even if a supersonic compound helicopter was theoretically
possible, it's unlikely to be practical. There are better approaches, such
as tiltrotor up to about 350 mph (570 kph), and beyond that V/STOL
winged aircraft.

-- Joe D.

Both the advancing rotor blade and the retreating blade on a helicopter
cause problems limiting maximum airspeed.

In many case, it is the retreating blade that limits first. Retreating
blade stall is announced by rotor roughness and vibration. In fully
articulated rotor blades, the retreating blade flaps down to the limit.
Then, because of precession, the nose will pitch up and the helicopter will
roll over.

At about the same time, the advancing blade will be moving at close to the
speed of sound. A sharp rise in drag produces shock waves which can cause
structural damage.

A number of years ago, in England, a pilot and crew were testing a
helicopter. At 11,000 feet and an IAS of 46 knots, the helicopter was
deeply in the retreating blade stall. It did two barrel rolls so large that
at the end of the second roll the aircraft collided with the ground.
Miraculously, the pilot and crew member survived. (This information comes
from "Principles of Helicopter Flight" in the Retreating Blade Stall
section.)

I have heard there is a jet powered gyrocopter that can fly at 350 knots or
so. Gyrocopters eliminate a lot of problems facing helicopters, but they
are still not very good at soaring.

Colin N12HS


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