Jump to content

Can the Magnus Effect be practically applied to aircraft?


Recommended Posts

Summer's coming and we'll see lots of polishing of cricket balls so that the bowlers can get lateral movement through the air. How so?

 

The principle the cricketers are depending on is the Magnus effect. The Magnus effect is an observable phenomenon that is commonly associated with a spinning object moving through the air or another fluid. The path of the spinning object is deflected in a manner that can be explained by the difference in pressure of the fluid on opposite sides of the spinning object.

 

This effect has been used in the past to replace the wings, or rotors of an aircraft with cylinders. 

On a cylinder, the force due to rotation is known as Kutta-Joukowski lift. The lift on the cylinder per unit length, F/L, is the product of the velocity v (in metres per second)  of the aircraft relative to the airflow, the density of the fluid, ρ (in kg/m3), and the strength of the vortex that is established by the rotation, G.

F/L= ρ.v.G

where the vortex strength is given by

G=(2.pi r)^2.s

or,

= (2.pi r)^2.ω

where s is the rotation of the cylinder (in revolutions per second), ω is the angular velocity of spin of the cylinder (in radians / second) and r is the radius of the cylinder (in metres).

 

To maintain a constant height, F (Lift Force) must equal the weight of the aircraft, so:   F = L.ρ.v.G, and to climb, F > L.ρ.v.G

 

Can this effect be applied to aircraft? Well, yes. Sort of. The Plymouth A-A-2004 was built in 1930 by three anonymous American inventors, and was reported to have made successful flights. 

editor_images%2F1535549833393-Flettner_Rotor_Aircraft.jpg

 

Once again, this early experiment was probably hindered by the available engine technology of the time. Some young experimenters have used this method for generating lift for RC test beds. Here are two videos that show that flight can be attained using the Magnus Effect.

 

This first video is a bit of fun, but shows some of the engineering problems that need addressing to perfect the rotation of the cylinders. The choice of cylinders may also adversely affect the result. 

 

Once the thing is flying, you can see that work is required to get the aircraft to fly more tail up in a normal orientation to the ground.

 

This video shows another application. This time the flight is better, but the video lacks the technical background of the first.

 

 

  • Like 2
  • Informative 1
Link to post
Share on other sites

Have always loved this concept but for human fun I would want a full airframe recovery parachute because if/when the engine stops no spin = no lift = no glide.

 

But I think it would be right up there with the UFO flying disc if someone could have a go at getting one flying and registered in the RAAus system.

  • Agree 1
Link to post
Share on other sites

Kasper has found the flaw in the otherwise flawless plan - if the drums stop spinning there is no Lift. Fortunately we now have recovery chutes. They would need to be an essential component. 

Link to post
Share on other sites

Oh there is another problem with this from a usable system - how to have seperate variabble control of the spin of the drums and the propulsive engine - you cannot have a fixed link between the drum rate and the forward prop because it will then become a single speed/altitude aircraft.

 

Why?  The lift is proportional to forward speed at a set drum rotation speed ... increase forward speed and lift increases so unless you can slow the drum rotation speed as you add forward speed it will not increase airspeed just go up and down at a set airspeed speed.

 

Ideal would be to have the drums rotate on electric motors as they are very controllable and have the forward speed on a seperate engine/motor prop.

 

Then you can have the fun of the mixing control for the 4 drums on 4 motors to give you pitch control (different drum rates fore/aft) roll (differential drum rates for left/right) and automatic alt hold to allow for different airspeeds (variable drum rates all around) ... mix it all with a good RC onboard autopilot and you can fly if by joystick control fly-by-wire.  Even more fun would be to add two forward thrust electric engine outboard at the front/rear and get yaw control by differential thrust.

 

You'd have to do this in RAAus becuase the CASA guy/gal faced with this nightmare will run screaming in the distance when you try to explain its a 6 motor fly-by-wire autostabilised magnus effect lifting device with no wing area and no stall speed cobbled together in my garage and managed with $300 of electronics from Hobby King I programmed up on this laptop 😁

 

 

  • Haha 1
Link to post
Share on other sites
49 minutes ago, kasper said:

You'd have to do this in RAAus becuase the CASA guy/gal faced with this nightmare will run screaming in the distance when you try to explain its a 6 motor fly-by-wire autostabilised magnus effect lifting device with no wing area and no stall speed cobbled together in my garage and managed with $300 of electronics from Hobby King I programmed up on this laptop 😁

 

Ha Ha Ha!

 

Have a look at the KFC video to see how he gets the drums rotating. I see your point about having each drum powered independently in order to provide roll movement.

 

From the video of the KFC buckets I formed the opinion that the engine should be a pusher, and set out like the Royal Aircraft Factory FE2D

image.jpeg.7db7b7a509a1091a974763fb09e0ced0.jpeg

 

The video also indicated that there needs to be a lot of weight forward of the CofG. Perhaps the everything forward of the cylinders could be set out like a regular plane, and the pusher prop driven by a shaft.

Link to post
Share on other sites

Nature never used the principle and the further you get away from how a bird flies, the less I like it. Watch an albatross fly. There's nothing much better for efficiency. Nev

Link to post
Share on other sites

Monstrous metaphors. Pernicious puns. Sympathetic similes. Malevolent malapropisms. Spontaneous spoonerisms. 

 

It all comes from my DNA. An early ancestor in the Jurassic dined regularly on Thesaurus.

  • Like 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...