I am having a little bit of trouble with the dive system I bought. Namely it has and atmosphric pump that transfers air from a wet cylinder to a dry cylinder (pressurising the dry one)...then when it is time to surface a non return valve is opened to let the air out.

Due to mechanical and seal losses it doesn't manage to fully push out all the water; hence such a cycle will leave the sub stranded after a short number of dives.

2 possibilities, either the air pump (what looks like two steam engine pistons) must run at the same time as the non return valve or the design is simply flawed.

I can either redisgn everything or supplent the chamber with some air (simpler solution). I am toying with the idea of using paintball CO2 cartriges and some sort of electronic trigger. I am slightly afraid of running a large capacitor in a submerged vehicle...gulp!

Can anyone comment...?...any suggestions????

Cheers...

Andrew.

the co2 should work wonderfully but youll need to get a porportional valve so you dont waste air or blow up you balast tanks

I know what you mean...I have found this system (thourgh a R/C Tank website), its a little more than I was willing to spend but it should provide about 50psi or 3atm...maybe less.

http://www.palmer-pursuit.com/online-catalog/rock.htm

I only need a little air, so I am currently planning to use channel 5 (landing gear channel) to control a 5v air pump. I am waiting for the regulator to be delivered so at the moment its all just an idea!

By the way, my model is a SeeHund...I think I may have found a way to disengage the torpedos...with magnets!!! Another funny little idea, if it works I'll be impressed...

Problem is I need a counter rotating gearbox with concentric shafts...any ideas?????

you mean a twin screw torpedo why not just use two mini moters(dont know the size of torpeedo)
do you have any links to where i could see this model or better yet on the specific torpeedo design
its these types of things that i have fun with ..... it makes me think!!!

The torpedo used two concentric shafts, this chap seemes to have a certain amount of success...

http://www.pt-boat.com/torpedo/torpedo.html

The model is similar to this one, although as the owner explained to me yesterday, mine is a vastly inferior model made in the mid 90s. Still great to cut my teeth on...

http://www.otwdesigns.com/Seehund/seehund.htm

The magnets I bought have a tractive force of 1.02kg which should be plenty. Found this servo:

http://www.huntersystems.co.uk/acata...o_Control.html

go down to Mega S04/BB 1/4 scale servo, I think it should be powerful enough to pull two of these magnets...do you know if I can run two of these servos off a single channel? Would I need some sort of in-line booster???

Cheers...

would it pull 2 of your magnets. ohh ya it would
booster for 2 of em. i would think it would lose some power but it should still have enough to pull thsoe magnets appart,this maight be a question for the radfio section.

(well now i know what concentric meant)at first i was thinking of the side by side twin torpeedos but this setup is grander than some of the things ive thought of(whod of thought of using a differential to run a inline twin)my ideas were ......well .....less thanideal for weight.
i would just try his way of doing it.
good luck