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Tubercles lower stalling airspeed?



 
 
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  #1  
Old May 14th 07, 05:13 PM posted to rec.aviation.soaring
RichardFreytag
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Posts: 8
Default Tubercles lower stalling airspeed?

This article: http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale fins actually
improve efficiency in fluid by lowering stall speed. I expect someone
here might have a good sense if this has any likelihood of working.

  #2  
Old May 14th 07, 05:37 PM posted to rec.aviation.soaring
bumper
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Posts: 322
Default Tubercles lower stalling airspeed?


"RichardFreytag" wrote in message
ups.com...
This article: http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale fins actually
improve efficiency in fluid by lowering stall speed. I expect someone
here might have a good sense if this has any likelihood of working.




I'm not so sure, Richard. I remember about a decade ago there was an
independent double-blind study done on the aerodynamics of humpback whales.
Best they could achieve was an L/D of about 0/1 when dropped from 10,000
feet.

bumper
Minden, NV
ZZ


  #3  
Old May 14th 07, 05:55 PM posted to rec.aviation.soaring
[email protected]
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Posts: 7
Default Tubercles lower stalling airspeed?

On May 14, 12:37 pm, "bumper" wrote:
"RichardFreytag" wrote in message

ups.com...

This article:http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale fins actually
improve efficiency in fluid by lowering stall speed. I expect someone
here might have a good sense if this has any likelihood of working.


I'm not so sure, Richard. I remember about a decade ago there was an
independent double-blind study done on the aerodynamics of humpback whales.
Best they could achieve was an L/D of about 0/1 when dropped from 10,000
feet.

bumper
Minden, NV
ZZ


As I recall pretty much came out about the same as a bowl of petunias.

  #4  
Old May 14th 07, 06:30 PM posted to rec.aviation.soaring
Ralph Jones[_2_]
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Posts: 117
Default Tubercles lower stalling airspeed?

On Mon, 14 May 2007 16:37:06 GMT, "bumper"
wrote:


"RichardFreytag" wrote in message
oups.com...
This article: http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale fins actually
improve efficiency in fluid by lowering stall speed. I expect someone
here might have a good sense if this has any likelihood of working.




I'm not so sure, Richard. I remember about a decade ago there was an
independent double-blind study done on the aerodynamics of humpback whales.
Best they could achieve was an L/D of about 0/1 when dropped from 10,000
feet.


But they did achieve a successful calibration of the Norden
Whalesight.

rj
  #5  
Old May 14th 07, 08:14 PM posted to rec.aviation.soaring
Nyal Williams
external usenet poster
 
Posts: 215
Default Tubercles lower stalling airspeed?

Whale of a 'tail.'



At 17:30 14 May 2007, Ralph Jones wrote:
On Mon, 14 May 2007 16:37:06 GMT, 'bumper'
wrote:


'RichardFreytag' wrote in message
roups.com...
This article: http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale
fins actually
improve efficiency in fluid by lowering stall speed.
I expect someone
here might have a good sense if this has any likelihood
of working.




I'm not so sure, Richard. I remember about a decade
ago there was an
independent double-blind study done on the aerodynamics
of humpback whales.
Best they could achieve was an L/D of about 0/1 when
dropped from 10,000
feet.


But they did achieve a successful calibration of the
Norden
Whalesight.

rj




  #6  
Old May 14th 07, 11:12 PM posted to rec.aviation.soaring
Shawn[_3_]
external usenet poster
 
Posts: 58
Default Tubercles lower stalling airspeed?

wrote:
On May 14, 12:37 pm, "bumper" wrote:
"RichardFreytag" wrote in message

ups.com...

This article:
http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale fins actually
improve efficiency in fluid by lowering stall speed. I expect someone
here might have a good sense if this has any likelihood of working.

I'm not so sure, Richard. I remember about a decade ago there was an
independent double-blind study done on the aerodynamics of humpback whales.
Best they could achieve was an L/D of about 0/1 when dropped from 10,000
feet.

bumper
Minden, NV
ZZ


As I recall pretty much came out about the same as a bowl of petunias.




Oh no, not again.
  #7  
Old May 15th 07, 04:47 PM posted to rec.aviation.soaring
Paul Repacholi
external usenet poster
 
Posts: 5
Default Tubercles lower stalling airspeed?

RichardFreytag writes:

This article: http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale fins actually
improve efficiency in fluid by lowering stall speed. I expect someone
here might have a good sense if this has any likelihood of working.


Was worked on in the wind tunnel by one of the east coast US unis, Princton?,
and they got up to about a 28deg AoA with a perspex replica of a Humpback fin.

  #8  
Old May 15th 07, 07:02 PM posted to rec.aviation.soaring
Bob Kuykendall
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Posts: 1,345
Default Tubercles lower stalling airspeed?

Earlier, RichardFreytag wrote:

This article:http://www.thestar.com/Business/article/213475
claims that the tuburcles on the leading edge of whale fins actually
improve efficiency in fluid by lowering stall speed...


Lower the stall speed? Probably. I can see them having the same effect
as adding typical blade-type turbulators in that regard.

Improve efficiency? It depends on what your measure of efficiency is.
I strongly doubt that it could make any improvement in best L/D. My
guess would tend the other way. I'd reckon that sucker-punching your
boundary layer is a sure ticket for a trip through the weeds.

Thanks, Bob K.
http://www.hpaircraft.com/hp-24


 




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