HI Guys
I hope you have all been busy doing your projects during this lock down.
A good friend of mine gave me one of the otw upholder model submarine, it had even got the tube with it and the 40mhz radio but my friend got so far through it and lost interest in building it, but as i have started to build it the first problem i came into when you filled the centeral ballast tank as it came to about half full the water pump would slow down to the point where it could not put any more water into the tank because of the pressure build up, even as though the tank had got a small pin hole at the top of the tank to let the air into the rest of the tube and the water sensor sits just below it to stop it filling so water does'nt go in to the rest of the tube. But no matter what i did the tank would not fill more than half full it would be interesting to know if any one else has had the same problem. even i stript the water pump down and rebuilt it and the water valve it still did the same, had a problem with the control board for the pump it decided to let the magic smoke out enough to say the board blow up, but the tube leaked and water got into the board ended up stripping it all down again and repaired and rebuilt the circuit board. The other problem i had was the cut out voltage on the board was the wrong voltage for the batterys i was going to use moded that and it now works for what i need it to do.
I Have done alot of modes on the tube inside one is when the sub dives the water sensors that was in the top of the ballest tank now has a small seperate tank with the water sensors in that there is one way valves so what happens is the tank fills so much with water then switches off the pump, the pressure build up inside the main tube is vented out through a snorkle with sits inside the conning tower so the air pressure goes back to normal pressure one bar, the snorkle is fitted with electro valve and all so works as a mushroom valve the mushroom valve works in such a way even if the tube heats up it lets air out to keep it at one bar pressure. When you blow the main ballest tank the first thing it does any water that has built up in the small seperate tank it sucks that water back into the ballast tank to pump it out as the pump starts to suck the water out of the main ballast tank the main tube in depressurized but as soon as the snorkle clears the surface of the water in the conning tower the snorkle opens and puts the pressure inside the tube to one bar normal air pressure There is another small over flow tank that is connected to the snorkle so if any droplets of water comes in the next time you dive it is blown out thrugh the snorkle
I don't have any more problems with the tank only half filling now and the tank now fills alot faster, the beauty about having a sub as small as this you can try the tube in the bath which make life easy not like trying to put a 12ft gato in the bath even the engal gato won't fit hope some body finds this interesting
All the best Sub John ps i did'nt think i would build another sub again but it just goes to show