RE: [PSUBS-MAILIST] Euvreka/fast sub design

["martlet1" <martlet1@sbcglobal.net>]

You're right, I think the Seawolf class subs can approach 50 knots.  The
bullet shape worked good in the air too, (like the Bell X-1) until they hit
the "area rule" at transonic speeds.  At that point, fuselages began to be
designed in a "Coke bottle" shape with tapered waists, like the F-105
Thunderchief (don't ask me why this trend was abandoned, certainly some very
successful supersonic aircraft of today don't have the "wasp waist").  In
WWII, control surfaces at very high speeds in air also created additional
problems like compressibility.  In transonic designs the wings are thin and
blended into the fuselage as on the SR-71.

>From what you saw, it sounds like in water, considerations of drag are
paramount to all others, and what you look for is minimal surface area - the
circumference of a circle.  I'm thinking that short wings and other control
surfaces would need to be sharply elliptical to reduce drag and symmetrical
in cross section so as not to create lift.

Just observations without any background in aerodynamics or hydrodynamics
beyond what I've read so far and can comprehend at 50 years old (man, it's
been a long time since Calculus II).  Just for grins, anybody know what the
speed of sound in water is?!

Texas Lake Diver

-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org]On Behalf Of William
Alford
Sent: Monday, April 14, 2003 11:23 AM
To: personal_submersibles@psubs.org; personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Euvreka/fast sub design


At 06:24 PM 4/12/2003 -0500, martlet1 wrote:
>I think that there's a lot that we as sub builders could learn from the
>design of supersonic jets.  That is, if we want our subs to go fast.
>Anything to reduce drag and frontal area.

I watched the excellent PBS documentary on subs last week (or before?). An
excellent history and many archival film clips from history. One fact that
stuck in my mind was the mention of USA research for nuclear sub's hull
design
for speed for which the result was that the fastest hull design was that
which
had a pure circle for any cross-section of any part of the hull. When you
look
at them, the nose looks like a bullet (hey, those go fast through the air!).
Apparently the research has been done for us-- Now building that is another
story.

William Alford