Everything Old is new again - Flettner Rotor Ship is launched

Found the following types of calculators and selected these as representational of the best of their type. IMHO.
Any of them the one you had in mind?

http://tomdove.com/sailcalc/sailcalc.html

http://www.wb-sails.fi/Portals/209338/news/SailPowerCalc/SailPowerCalc.htm

http://www.gosail.com/boatRating.html

http://www.sailingcourse.com/keelboat/cal_wind_load.htm

 

As to cylinder construction. Among other things, I'm a drummer. I have quite a 'collection' of old drums.
Would the cylinder HAVE to be made of carbon? Laminated wood is strong.
I'm thinking nested drum shells about 12 feet high when extended. Diameter of lowest shells 16 inches and highest shells 12 inch diameter. Various diameters in between consecutively nesting within each other. Circular end plates at each diameter change. Cogs on captive bottom plates of each higher cylinder, engage notches in the inner perimeter cutout of top plate that's part of cylinder beneath. A simple expedient locking all the extended tower together to spin in unison.
Obviously I'm envisioning ability to 'FURL' or collapse this cylinder in heavy wind.
Impregnating these drum shells with epoxy inside and out, could they withstand the spin? they're perfectly round, or drum heads wouldn't fit!

 

Good one Yo - I dont know the best method of calculation for sail thrust, but if you did a few, and got an average, that would be good enough.

Your ideas all sound sensible, though getting a wind powered spinning device to work might be best left till you get the actual rotor built and working.

The choice of hydraulic or electric power will be important.

I think you have an inboard diesel, but is that correct ?

I attach another photo of a Flettner rotor on a small boat for your info.

I reckon you ought to start a new thread in PROJECTS and PROPOSALS, and we can post threads in all the areas of interest like Hydrodynamics and Aerodynamics, Boatbuilding - Metal, for welders and metal cutters, Fibreglass for input on the shell.

I will be offline for a couple of days, but I will be back asap.

Keep up the good work

 

Man look at that thing go!

https://www.youtube.com/watch?v=VuobfwRo-IE

 

That's exactly what I needed to see! and slung beneath a tripod mast too!
Exactly what I have in mind.
Thankyou!

 

Yes, "that thing" is fast. But it was never nearly as fast as this design with the original sails which made more than 15knots and the conditions in Flensburg were very special (direction of wind, flat water etc.).

Stephen Thorpe tried another approach: http://www.thedailysail.com/dinghy/...boat-adds-a-new-dimension-to-aerodynamic-theo and http://www.ayrs.org/flettner.pdf. His very remarkable hp www.rotorboat.com is no longer online. But I`ve got it printed out.

Overloaded small catamaran with rotor on Nile River: http://www.youtube.com/watch?v=ao8RfUermdw

When we speak of Flettner rotor and Magnus effect it should not be forgotten, that this phenomenon was first discovered by Isaac Newton 1672, then 1742 by Benjamin Robins, British mathematician, ballistic researcher and military engineer: "Why do cricket balls swing and curve balls curve ?". Heinrich Gustav Magnus came 1852. May be we should better speak of the Robin`s effect ?

Flettner rotor aeroplane: http://www.youtube.com/watch?v=acXvl-8xrBM and http://www.youtube.com/watch?v=GAqLyyg2AHk and http://www.youtube.com/watch?v=hlmvHfIAszo

 

I was in personal contact with Stephen Thorpe and his boat was talked about in this thread.

http://www.boatdesign.net/forums/bo...r-rotor-ship-launched-24081-3.html#post393555

Too bad his site is down and I lost his email.

IMO his effort of using a tapered rotor without an endplate is superior to using a cylinder with an end plate, in exactly the same way tapered/eliptical wings and foils work better than jamming an end plate on a crude planform.

 

If the tube was made collapsible (which would be possible with a tapered section as the small sections will fit inside the larger ones) it might store away small enough to use on your yacht tender and require a very small solar panel. I think Stephens boat used only 20w or so?

 

His email has been: mail@rotorboat.com. You will find it at the end of this article: http://dtyoe.wordpress.com/2008/05/24/an-articel-to-my-rotorboat-by-stephen-thorpe/

 

started a new thread here

http://www.boatdesign.net/forums/pr...-frettner-rotor-project-50587.html#post690828

 

Actually, there have been a lot of test with these 'plates', and they increase efficiency by huge margins. It like the jets t hat have winglets on their end tips.

Jo Norwood recommended multiple Thom Gates, and this attached excerpt from 21st Century Sailing Boats shows the formula e that illustrates their efficiency

 

He was one of a continuing stream of investigators, and didn't solve the equations.

Sir George Cayley (1773-1857) - did a lot more on the topic,

Frank H. Wenham (1824-1908), a Council Member of the Aeronautical Society of Great Britain, is generally credited with designing and operating the first wind tunnel in 1871.

Otto Lilienthal (1848-1896) has been called the world's first true aviator. Although he built no powered aircraft, his hang gliders made him world famous and generated great enthusiasm for manned flight. Starting in 1891, Lilienthal flew-actually glided-over 2500 times, covering 270 yards in his longest attempt. He amassed more air time than all his predecessors combined.

Sir Hiram Maxim (1840-1916). An American living in England, Maxim had made a fortune with his famous machine gun. ...., he built large elaborate testing facilities and aircraft to match his immense aspirations. Maxim first tested airfoils.

etc etc

 

Folding / Retractable Flettner Rotor

Compliments of Alan Sailor, a good place for this reference

"The THiiiNKsail© RFR flettner rotor system is controlled by software and monitored from the bridge. It requires no additional crew. The system has been developed and tested both in tank tests and in full-scale sea trials. It is suitable for inclusion in new-build designs and ,importantly, can be retrofitted on existing vessels"

http://www.thiiink.com/advantages-rfr-technology/

 

The rotor would have to be a special case then as winglets/plates are only used on a very small percentage of wings in the real world. Span and more complicated planform gets a better result on wings. Wing keel boats usually sail worse than the longer span non winged version.

But the rotor is not really a wing so these rules probably don't apply in the same way. I still think that a tapered rotor may work well and plates could still be used. There has been no back to back tests done on tapered rotors that I have seen so the potential might still be there?

 

You are arguing against a lot of research. From Flettner to Norwood, engineers have tried all sorts of variations.