[MHml] Proa/Flettner, re-living MM´s

[George Wade]

Many thanks, Chris & Roy, for this enquiry.

I expect the Flettner rotor to be useful over a particular range of  
apparent wind directions;  and for propulsive force + drag to be  
unuseful 1) dead downwind  2) near fine reaching or so.  Also --- for  
the force developed to be closely dependent upon the ratio of the  
circumferential velocity of the rotor as a proportion of the apparent  
wind velocity from instant to instant.  Ie. A gust may not hit as  
hard as expected because the ration of velocity of the rotor surface  
to wind velocity would go down:  depending on how the rotor is turned.

As the students are being given a 'Thinking Exercise' by their Prof.   
they may not have come across all of these considerations, just yet.   
Make them think.

It may act like a Spinnaker --> Fat Screecher ??  But I'm guessing  
from past readings of Marchaj.

George


On 2-Oct-06, at 8:19 AM, Claus C Plaass wrote:

>> From: Roy Mills <rsirfj at shaw.ca>
>> Subject: Re: [MHml] Proa with Flettner: Which MM issue ?
>>         Darn you for a time waster Claas.
>>          However, it was very interesting in
>> many other ways, pictures of state of the art ocean racers
>
> You`re welcome, Roy, I experienced exactly the same:
> The F-40 story, the upcoming French monsters, sketches,  tables, etc.
> all handcrafted into MM`s "famous" b&w pre-computer look.
> And guess what ? It worked well as a "Multihull Magazine" then,
> and after 31 years in a market full of color mags, still lives.
>
> Here´s a first impression on the "flettner´ed" proa

> :.....phone call of proa project head Prof Fiesser -
> thanking me for my tip, which meanwihle led to the debuggng.
> I am invited to test sail her back on Wednesday,
> and to further tests at the Flensburg University.
>
> The boat itself is well built and dimensioned,
> and her detailed solutions are nice thought out.
> An article with detailed shots will follwo in MM.
>
> Chris
> Kiel, Germany