Re: [PSUBS-MAILIST] fins on dragged naval sonar

[Coalbunny <coalbunny@vcn.com>]

Also, long and narrow boats are more stable than short and fat ones.
Carl


Cliff Redus wrote:
> 
> Not exactly classic teardrop shape.  The classic teardrop shape has a length
> to diameter ratio of approximately 6. The boat shown in
> http://www.sfu.ca/casr/101-navvds.htm looks more like an L/D of  2.5.  To
> drag (no pun intended) everyone back to school; for turbulent flow around an
> axisymmetric body of revolution, there are two contributions to overall
> drag, the first is skin friction and the second is form drag.  As the L/D
> ratio increases for a teardrop shape, the form drag decreases and the skin
> drag increases.  The total drag being a combination has minimum around an
> L/D of 6.  Modern military boats use a higher L/D because even though not
> optimum, at higher L/D's than 6, the total drag does not increase very
> rapidly. With higher L/D's than 6, they can pack more kit in the boat
> without paying to much of a drag penalty.  "Concepts in Submarine Design"
> Burcher and Rydill (1999) pg 105.
> 
> Cliff
> ----- Original Message -----
> From: <dinosnider666@spacemail.com>
> To: <personal_submersibles@psubs.org>
> Sent: Wednesday, October 22, 2003 2:04 PM
> Subject: RE: [PSUBS-MAILIST] fins on dragged naval sonar
> 
> >
> >
> > http://www.sfu.ca/casr/101-navvds.htm
> >
> > Classic teardrop. Pretty huge fin control panels. Reminded me of circular
> band at back of original bazooka.
> > Anyone else know any unorthodox fin configurations?
> > D.

-- 
"Without deviation from the norm, progress is not possible" - F. Zappa