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NutLoose
18th Apr 2018, 20:43
I had never heard of it until I saw the aircraft this kid has built, it uses the spinning effect used to curve footballs in flight.

Watch the film, fascinating and very very clever.

https://forum.keypublishing.com/showthread.php?144884-Young-kid-builds-and-flies-amazing-Magnus-Effect-plane&p=2439021#post2439021


https://en.m.wikipedia.org/wiki/Magnus_effect

You learn something new every day.

megan
19th Apr 2018, 01:49
There's nothing new under the sun as they say, well, the idea anyway, though it wasn't successful.

https://en.wikipedia.org/wiki/Flettner_airplane

https://www.youtube.com/watch?v=_XMT5aBBaMI

ChrisVJ
19th Apr 2018, 04:24
I am sure I saw a prototype manned helicopter on 'Tomorrw's World' maybe some late sixties or so on which the blades were long cylinders of relatively small diameter. It demonstrated flying qualities that helicopters don't have, including an actual loop. (Yes I have seen a helicopter loop, but that was much later.)

ORAC
19th Apr 2018, 06:37
Been used on ships for many years....

https://i.kinja-img.com/gawker-media/image/upload/s--THBgUVcf--/c_scale,fl_progressive,q_80,w_800/edlk7qunpejjw0if2ud1.jpg

https://www.marineinsight.com/wp-content/uploads/2011/09/65213_8.jpg

https://youtu.be/IouXKW298YQ

Fareastdriver
19th Apr 2018, 08:04
I remember a theory at Farnborough in the sixties. There was a model of a Trident with a pole that could be retracted into the fuselage for cruising flight. On arrival it would erect and be rotated by engine bleed air, come to the hover and land.

goudie
19th Apr 2018, 10:44
Brilliant stuff, I’d have lost money, betting it would never fly.

Icare9
19th Apr 2018, 12:21
Ah! I used a school ruler to produce this effect, spin it backwards and launch - it really is a surprise!

G-CPTN
19th Apr 2018, 12:34
Ah! I used a school ruler to produce this effect, spin it backwards and launch - it really is a surprise!

Been there - done that (often) - though I never knew why it worked.

VP959
19th Apr 2018, 13:15
Always worth a look in the NASA Technical Library for stuff like this, as they have done a really good job of archiving all the old NACA papers.

There's an interesting Technical Note that examines the forces acting on a rotating cylinder in an airflow in Technical Note 209, dating from December 1924 that describes the lift and drag characteristics discovered from wind tunnel tests fairly well: https://ntrs.nasa.gov/search.jsp?R=19930080991&hterms=Technical+Note+209&qs=N%3D0%26Ntk%3DAll%26Ntt%3DTechnical%2520Note%2520209%26Nt x%3Dmode%2520matchallpartial%26Nm%3D123%7CCollection%7CNASA% 2520STI%7C%7C17%7CCollection%7CNACA

It looks like the L/d can approach 8:1 for a rotating cylindrical "wing". Not great, but not too shabby either.

Groundgripper
19th Apr 2018, 14:25
Ahh...NACA Tech Notes. I spent many an hour in the basement of the Aero Society rummaging through them when I worked for ESDU.


GG

VP959
19th Apr 2018, 15:02
Ahh...NACA Tech Notes. I spent many an hour in the basement of the Aero Society rummaging through them when I worked for ESDU.


GG

Nice and easy to search now, thanks to the generosity of NASA, but if you just want to browse the NACA TNs from a UK library, then Cranfield have made them available online: MAGiC NACA Archive (http://naca.central.cranfield.ac.uk/)

Edited to add:

I forgot to put the link in to the NASA library server earlier: https://ntrs.nasa.gov/

ShyTorque
19th Apr 2018, 15:22
Over fifty years ago a school pal of mine had a kite that flew using this principle; I never knew it was called the Magnus Effect tho'.

Haraka
19th Apr 2018, 18:07
Over fifty years ago a school pal of mine had a kite that flew using this principle.

Probably a Palitoy "Revojet Plane ". They were quite popular and made a distinctive clattering noise.

RAT 5
19th Apr 2018, 18:46
Whatever the future, and even the present, for this project I salute and applaud the young man for his brilliant engineering endeavour.
A honestly earned 'well done' and may you have a bright and successful future. :ok:

D120A
19th Apr 2018, 19:13
I still have the 1950s American toy similar to the Revojet, called the Skyro Plane. My grandson loves it and it certainly turns heads in the park. Two S shaped 'wings' rotate in the airflow on rigid wire spindles and the aircraft flies like a kite on a thread dispensed from a fishing rod. Google 'SkyroPlane' and you can see examples. Occasionally they emerge on eBay.

The lift generated by the circulation (integral of v.ds around the surface for the mathematical) around a cylinder (or a wing) is given by L=air density x velocity through the air x circulation. See:

https://www.grc.nasa.gov/www/k-12/airplane/cyl.html


You don't have to rotate the cylinder, you can blow gas around it from tangential slots to produce a net circulation and it will generate a force in an airflow. That is how the yaw force is generated by the tail boom in NOTAR tail-rotor-less helicopters. Professor I C Cheeseman demonstrated a similar 'barbers pole' rotor device at Farnborough in the 1960s where smoke generators proved the existence of downwash when exhaust gas was blown through slots.

And, of course, the Dam Busters' Upkeep weapon depended on the Magnus Effect in its final stages. Still spinning backwards, as the mine sank through the water the Magnus Effect forced it up against the dam wall. This magnified the effects of its depth-fused explosion by tamping the water. I always thought that was the really clever bit.

Icare9
20th Apr 2018, 12:21
Blimey! Never realised the Magnus Effect was responsible for the Upkeep against the Dams!
Thought it was just the rotational effect of the cylindrical case - never thought that a smooth cylinder would have a magnus effect aspect.... YLSNED! Thanks for that D120A

megan
21st Apr 2018, 01:37
Always regarded Magnus as being closely allied with the Coanda effect.

https://www.youtube.com/watch?v=kR2Oi3XCX18

meadowrun
21st Apr 2018, 02:16
Going off topic - Why wasn't the first steam engine attached to anything that would do work?


(Heron and Vitruvius draw on the much earlier work by Ctesibius (285–222 BC)


http://s2.hubimg.com/u/4670081_f520.jpg

Ascend Charlie
21st Apr 2018, 02:18
Why wasn't the first steam engine attached to anything that would do work?

...because nobody had invented gears / chains / rubber belts / pulleys / bearings blah blah

meadowrun
21st Apr 2018, 02:23
Rope? Cogs?


Seems a logical extension of the process.
This thing spins. It has power but too bloody dangerous to get near.
Could that rotating power be transferred to something unpowered and room temperature?
How could we do that? A nice trip hammer without all those troublesome slaves would be good.

PDR1
21st Apr 2018, 14:44
Because it developed extremely low levels of torque, so it needed to run at high rpm with the associated gearing to produce usable power. With the technology of the day the associated static friction was too high and the transmission efficiency was too low. The reduction drives available to the Romans were essentially ropes and pulleys (very high static friction) or wooden interlocking-peg contrate gears (high dynamic friction due to sliding peg contact).

As a technology it sits with the flame-licker/flame-gulper vacuum engines and the low-pressure Stirling engine - very low torque devices which only work if the balance between fits and friction is precisely right. I've made several "coffee-cup sterling engines" (google it) and each one has needed half a dozen attempts at the piston to get a fit with a good enough seal without friction - even though the pistons are turned from graphite (an inherently low-friction material).

To make usable steam turbines like the above, let alone actual steam engines, the romans would have needed to first develop precision machining, and to do that they would need to have worked out how to do precise and repeatable screw threads. They were nowhere near developing those technologies.

0.00002 supplied,

PDR