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Brent (and Frank)
I think a tail cone would work.....but just a
horizontal surface one diameter from the center (at the aft end or stern) would
keep the bow pointed either up of down (surfacing or diving) to prevent the
vortex's from forming. The size would be important, but without some in-depth
testing, I couldn't say.
I just don't want Frank to be come sea sick if the
event ever arose. I know the oscillations can get pretty severe depending on the
shape and the speed.
I know if the craft has some forward motion the
effect is less likely to happen.
Frank may have already tested for the
phenomenon.
Just don't do a full ballast blow the first time at
depth. :-)
James Long
Owner/Designer
Lil Brother LLC (Instrument Division)
----- Original Message -----
Sent: Tuesday, July 24, 2007 12:10
AM
Subject: Re: [PSUBS-MAILIST] Saucer Sub
Design
Here is a quote from the plague on the Dennock
Submersible
"TAILCONE - The tail structure serves a dual
purpose. It protects the
hoses exiting the rear of the submarine and
maintains stability during
rapid accent. Without it, a phenomenon known as
"vortex shedding" would
cause the relatively bulbous submarine to oscillate
uncontrollably
during surfacing, similar to the way a leaf
falls."
Because of this,
I would consider adding large stern control surfaces, and perhaps make
the stern fairing longer.
Brent
From: "Lil Brother LLC"
<lil_brother_llc@bellsouth.net>
Reply-To:
personal_submersibles@psubs.org
To:
<personal_submersibles@psubs.org>
Subject: Re:
[PSUBS-MAILIST] X Thruster Arrangement
Date: Mon, 23 Jul 2007
22:57:25 -0500
Frank,
I hate to hear that......but it's better to find out on the model, than
on the real thing.
I would like to know how stable the craft is on the move to the
surface?
Seems to me if you were rising to fast, it would tend to wobble. (I
have an aerodynamic background, not as an engineer, but I did work and study
aircraft for quite some time.)
James Long
Owner/Designer
Lil Brother LLC (Instrument
Division)
----- Original Message -----
Sent: Monday, July 23, 2007 10:36
PM
Subject: Re: [PSUBS-MAILIST] X
Thruster Arrangement
Thanks James, It used to look a lot more like a flying saucer, but
the original ballast tank design failed miserably in model testing.
Still learning from my mistakes. Frank D.
Get a sneak peek of the all-new AOL.com.
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