Everything Old is new again - Flettner Rotor Ship is launched

Interesting concepts Mr R

 

unstoppable

I seem to remember a similar idea (or this one) being featured on the BBC Science and Technology show "Tommorows World". I guess it must have been over 2 decades ago.

Anyway that prompted a discussion over a few beers at the local sailing club - and resulted in a tale of woe (or maybe Whoa) involving sailing dingies, ambiguous club rules and a 'gentleman' with enough knowledge of aerodynamics to be dangerous.

From memory, the guy in question had found some badly damaged helicoptor rotor blades in a scrap yard and had chopped them down to 5 or 6 foot and mounted three on the wheel hub of a scrapped car to give a rotor, this was fixed to the top of the mast with the plane of the rotor perpendicular to the deck and arranged so that the direction it was facing could be moved and adjusted throughout 360 degrees. Think of an Autogyro on its side.

As air passed through the rotor it generated thrust and also span the rotor faster making it more efficient at generating thrust. the problem was that it tended to get so fast that it acted like a gyroscope preventing the dingy/rotor from being turned - was in a smaller lake so a bit of a problem...
But in light winds he was able to make good speed when his fellow sailors were left with their sails flapping which caused some ill will, not to mention it was probably pretty terrifying to be close to...

Then there was a stroke of genius - the wheel hub was from a car - which had ... BRAKES! Once able to slow the rotor enough to change course as required, he became bolder and was then able to operate in stronger winds...

Eventually though the inevitable happened and when the brake failed the happless individual found himself unable to steer or stop as he accelerated ever faster across the water. The impact with the far shore destroyed the Dingy, and the mast snapped off with the rotor still spinning like a giant ninja thowing star which seemed to be aimed with great precision at a nearby herd of cattle though fortunately none were injured.

There may have been some embellishing on the details - a great fishermans tale over some good beer - but I always trusted that the essentials of the story were true...

 

http://www.rexresearch.com/boats/1boat.htm#lesh
Anything to these sword blade shaped rotors?
Since they are shaped like "surfboards" claims the article, if they were foam filled, assembled together as a catamaran dinghy in port.
I'd go for rigid rotors if I could use them that way.

 

They never built a full size version - the vibration on the smaller scale models was intense enough - as I remember it.

 

How is a propeller similar to Flettner Rotors ?

 

not a prop

OK I skipped a few stages of how the discussion got from the Flettner rotor, via dimples in golf balls and some less than complimentary comments about whether that effect was the reason for one member of our party's poor ability on the pool table

True enough it is not a Magnus Effect rotor, the vessel in question is still a rotor vessel (and more so than the turbo sails earlier in the thread) - no energy is supplied to spin the rotor other than from the wind. So, definately nothing to do with propellers.


While the original blades were from a Helicopter, they were being used in a configuration that had much more in common with an autogyro - the spinning rotor disk is presented edge into the wind (with a small angle of 'attack' to harvest some wind energy for rotation) and the wind passing through/across the spinning disk makes it behave like a solid aerofoil generating (lift) thrust perpendicular to the plane of the rotor - as the rotor is on its side a vector component of that thrust can propel the vessel forward (or be used to slow it down). It cannot sail directly into the wind but is far closer than a traditional sail. The downside is in terms of practicality - as was demonstrated by the 'prototype' - changing direction has issues but for a long distance ocean voyage this is minimised.

It was probably over 30 years ago - with more modern materials and maybe an active hub to change the flare of the blades preventing it from 'running away' it might be due for a return.

Unlike a sail - the rotor will extend way past the top of the mast and therefore the given 'rotor sail' area can be much larger for a given mast height. I guess if the blades were articulated allowing the rotor to be collapsed and bundled the storage space would be miniscule on a larger transatlantic vessel.

I suspect this is another area where the concept is waiting for materials to catch up - can you imagine where we'd be today if DaVinci had access to a 100 HP Rotax motor and a roll of dacron...:idea::idea::idea::idea:

 

An autogyro rotor could be used for sailing. However, its strengths would be to be very stable in gusts and handle high winds more easily. Such a rotor beating regular sails in light winds must be part of

.
If the rotor could also be pivoted horizontally this would allow turning without braking the rotor first and it would provide a component of horizontal lift given enough wind to sustain the rotation. Note that helicopter blades used in a autogyro fashion are bolted on upside down to use the twist in the blade for air to drive the rotor.
The general idea is discussed in this patent.
But this discussion is rather far removed from the topic of this thread with only a rotary motion in common.

 

Looks like pretty soon there will be another rotor ship - http://www.marinelog.com/index.php?...ial-norsepower-rotor-sail-on-ro-ro&Itemid=231

http://cdn2.shipspotting.com/photos/middle/9/3/1/2079139.jpg

 

Well spotted LJ

Found some more info from your link here

http://www.norsepower.com/

Claims :-

"The Norsepower Rotor Sail Solution is the first commercially available auxiliary wind propulsion solution. "

 

Test rig illustration

http://www.marinelink.com/news/harnessing-propulsion373430.aspx

 

So, so far there are norsepower.com, monorotor.com & thiiink.com - all offer same solution & ship owners still struggling from using it.

 

The valid cause for hope and optimism is, folks are trying. They're looking and thinking and investigating and investing in R&D.

Doesn't that brighten your day? Smile!
Human beings are generally nice people.
On average, pretty intelligent.

Until they form a mob.

 

How do you mean ?

 

Flettner in Egypt

I found this video of Flettner on a small boat.
3 parts to the video.
Really bad cell phone video. The guy has no clue about video taking.
Still, it looks great for a DIY rotor.

Magnus Effect Boat in Nile River 1
https://www.youtube.com/watch?v=ao8RfUermdw

https://www.youtube.com/user/amrgamalsami/videos

If the Egyptians can do it in 2009....

 

Flettner aircraft

For those who can't understand how a spinning tube can create lift...

https://www.youtube.com/watch?v=gjMbfxsHXw4

The front propeller pulls the "plane' forward, the spinning Flettner rotor only creates the lift. And it does indeed LIFT.

Stick two Flettner rotors horizontal out the sides of your boat.
Put an aircraft engine and propeller on the bow.
Get going at a good forward clip.
Spin the rotors fast enough and your boat would lift off.

Not that you might want to do so.
I guess that could be cool for a zany hydrofoil though!