Hi Brian,
Yes, epoxy & you need to try it on the polystyrene first, as some additives
in some epoxies can dissolve polystyrene.
Acetone does a good job on polystyrene. Petrol can dissolve it. It dissolves down to a
hard thin layer. Sometimes flakes of it come off, so you'd want to make sure these wouldn't
travel anywhere where they're not wanted.
I was thinking you would need to glue several blocks made of some heat resistant material
like aluminum, around the motor, flush with the level of the polystyrene, so the fiberglass jacket
was left suspended around the motor on these.
A further thought was that you could calculate the volume of air required to counteract any
buoyancy problems caused by the motor at the back of the sub. & incorporate this in the size
of the motor jacket.
Alan
----- Original Message -----
Sent: Saturday, February 26, 2011 7:12 PM
Subject: Re: [PSUBS-MAILIST] pressure compensated outboard
I did think of Frank when thinking of this, maybe he's still influencing our thought process more that we know ! so you're saying create a very small amount of an air pocket. Somehow I was thinking steel, but that really wouldn't matter with an ambient situation. A fuel bladder would work also. How does one go about dissolving polystyrene? Actually polyester resin is not compatible with styrene so you would have to use an epoxy - which would be so much the better anyway.
Brian
On Fri, Feb 25, 2011 at 7:18 PM, Alan James
<alanjames@xtra.co.nz> wrote:
Hi Brian,
there are flexible fuel tanks that have the advantage in that they would be pressure resistant
& as your fuel level changes your buoyancy wouldn't change; or not significantly.
You could possibly cover the motor with thin sheets of polystyrene then fiberglass over it &
dissolve out the polystyrene leaving a small pocket of air around it.
I'm sure if Frank were around he'd be on to this. He wanted to put an outboard on Git Kraken.
Regards Alan
----- Original Message -----
Sent: Saturday, February 26, 2011 3:10 PM
Subject: Re: [PSUBS-MAILIST] pressure compensated outboard
Hi Alan,
That was my first thought, if any components would be affected. I can't see where there would be a problem, anything that has gasoline in it would be safe as far as pressure is concerned. I'm thinking a 20 hp or so outboard, electric start, fuel injected. I think most of those are water cooled so that would be a plus. I would just turn the whole cylinder to steer, and mount the thing in there good. Have a fuel line that could be valved off, the fuel tank might have to be pressure resistant.
Brian
On Fri, Feb 25, 2011 at 5:58 PM, Alan James
<alanjames@xtra.co.nz> wrote:
An ambient outboard!
Sounds like an idea with a lot of potential Brian.
I'm wondering if there are any components that may be affected by the air pressure.
How big a motor are you envisaging? What sort of motor controls?
Regards Alan
----- Original Message -----
Sent: Saturday, February 26, 2011 12:57 PM
Subject: [PSUBS-MAILIST] pressure compensated outboard
I have an idea for a pressure compensated outboard engine so as to give surface power for my sub. Basically it would be a "can" that would cover an outboard engine with an opening on the bottom. There would be a float valve located near the bottom of the opening so when I submerge, as the water begins to move up into the cylinder, compressing the air, the float valve would inject air. That way it would keep a constant volume of air in the outboard engine compartment. As you assend the extra air would simply expand out the bottom.
Brian