It's good to test everything you can if possible.
Here's one more tip- after getting your dome, take it out in the
bright sun and look at it with polarized sunglasses at various angles.
A slight reddish look is expected (mostly around the edge).
If the dome shows a "rainbow effect" through the filters
you've got problems and will need to stress relieve it again.
If you'd like to email me a picture I'd like to see it.
Greg C.
--- On Mon, 5/24/10, Alan James
<alanjames@xtra.co.nz> wrote:
From:
Alan James <alanjames@xtra.co.nz> Subject: Re:
[PSUBS-MAILIST] Rudders To:
personal_submersibles@psubs.org Date: Monday, May 24, 2010, 4:38
PM
Greg,
Thanks for the advice &
offer.
I live in NewZealand, so it might be
cheaper to buy an oven
than send the dome over &
back.
I have been on to the plastics
manufacturer about annealing
& he ensures me it will all be done
by Stachiws book. I will
pass on more information to him but I was
expecting a picture of
the finished dome yesterday, so it may be
too late.
That was an eye opener about the
unannealed dome failing at 50ft.
I had thought I'd be safe to this range
without doing an unmanned test.
Regards Alan
----- Original Message -----
Sent: Tuesday, May 25, 2010
1:27 AM
Subject: Re: [PSUBS-MAILIST]
Rudders
Make sure that the fabricator is going to anneal the
dome- this is where the strength comes from. Ask them to give
you the annealing schedule. For a 1" thick dome it should be
179 F held for 24 hours in a convection oven, Then cool at no
more than 10 F per hour for 6 hours, fan off. If you're not
convinced that they know how to do this then give me a call
and I'll do it here.
Greg C.
--- On Sun, 5/23/10, Alan James
<alanjames@xtra.co.nz> wrote:
From:
Alan James <alanjames@xtra.co.nz> Subject: Re:
[PSUBS-MAILIST] Rudders To:
personal_submersibles@psubs.org Date: Sunday, May 23,
2010, 10:14 PM
Thanks for the confirmation
Greg.
I'll leave off the dive plane
for now & see how it goes.
Had a photo a couple of days
ago of my sheet of acrylic bolted down ready for
blowing.
So after a year of waiting I
may hopefully have a dome this week.
Alan
----- Original Message -----
Sent: Monday, May 24,
2010 2:09 AM
Subject: Re:
[PSUBS-MAILIST] Rudders
I agree with Vance on the problems associated
with trying to vector up and down with thrusters
that are also used for propulsion
(although I don't have any experience with rudders).
The solution I prefer is to have a dedicated
vertical thruster. The additional benefit is that a
vertical thruster allows the sub to descend
while set for slight positive buoyancy. In this
configuration, it is the thruster (with variable
speed control) that pushes the sub down to the
desired depth, then the thrust is reduced to the
point where the sub is "hovering". Then the main
thrusters provide propulsion only. The major safety
benefit is that the sub will naturally return to the
surface in the event of a system failure
just by cutting power to the vertical thruster. I
found it to be more relaxing to dive a sub set for
positive rather than neutral or (heaven forbid!)
negative.
Greg C.
--- On Sat, 5/22/10,
vbra676539@aol.com
<vbra676539@aol.com>
wrote:
From:
vbra676539@aol.com
<vbra676539@aol.com> Subject: Re:
[PSUBS-MAILIST]
Rudders To:
personal_submersibles@psubs.org Date: Saturday,
May 22, 2010, 8:05 PM
There are some issues with using pivoting
thruster pairs for this sort of double duty,
especially in small thrusters on heavier vehicles.
When you vector down or up, or need to correct
steering, forward thrust is lost. Also, the lack
of control surfaces means that any correction must
be powered. Vehicles will not continue to turn,
for instance, once the power is switched off. You
can do very well without those control surfaces,
of course-----until you use a rudder and dive
planes for awhile-----then you see what you've
been missing.
Vance
-----Original
Message----- From: Alan James
<alanjames@xtra.co.nz> To:
personal_submersibles@psubs.org Sent: Sat, May
22, 2010 5:23 pm Subject: Re: [PSUBS-MAILIST]
Rudders
Thanks
Pierre,
is there a discount
on the posters with Psubs membership?
Alan
----- Original
Message -----
Sent:
Saturday, May 22, 2010 11:23 PM
Subject:
RE: [PSUBS-MAILIST] Rudders
Yes
that’s me! Please stand in-line for a signed
poster.
A
good design to control sub with 2 motor is to
have them in the center of mass (from front to
rear) and as far away from each other (side to
side).
I
also have mine so they can rotate on the shaft.
So I can use them for up/down
movement.
Pierre
Sorry
Pierre, It's clicked who you
are.
The
world famous owner of "big".
Your email
name through me out.
below
is a link to a glossary of submarine terms found
on the
"Deep
search site" that's quite
good.
-----
Original Message -----
Sent:
Saturday, May 22, 2010 4:13
PM
Subject:
Re: [PSUBS-MAILIST] Rudders
Any
photos of your sub you can refer me
to?
-----
Original Message -----
Sent:
Saturday, May 22, 2010 2:37
PM
Subject:
RE: [PSUBS-MAILIST] Rudders
Hi
Alan,
My
use a very similair design with one motor on
each side and I don,t have a rudder. With one
full foward and one full backward, I can almost
turn on the spot. Same as a
bulldozer.
So
no, I would not waste time on
rudders.
I
have been looking at some videos of a small 1
person semi-dry ambient sub in
action.
This
sub doesn't have a rudder & just uses
differing motor speeds to
turn.
As
I'm building a small 1 person sub of a similar
size with two PWM controlled motors I'm
wondering
wether
a rudder is going to be a waste of time for me.
I did have a rudder in my original
design.
Any
thoughts on this thanks.
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