Never Built or used a RC sub before

[FNG2k4]

Hi,
Just doing some research and found this forum.
I have my open water certification and have been lucky enough to scuba dive in the red sea but have not had a chance to scuba dive since but have always been interested in the open sea. I hope to eventually make an underwater rover, maybe solar powered that would just wander the deep ocean and when it runs out of power surface and send the data its collected then continue on after reaching full power but I figured I should start small with a RC sub. I just thought with my electronics engineering I should be able to make/design all the elctronics on a RC sub and that would also be a great senior project so I'm starting to really like the idea of making a RC sub and was wondering where I should start. I would also like to try making it from scratch as I am working on a college budget of broke to begin with.

Thank you,
FNG2k4

[d3snoopy]

I'm just starting on a scratch built RC sub of my own, so I'm not all that experienced, but here's what I've gathered so far: There seem to be two catergories of RC subs out there: The ones that are ARF style- charge it up, turns it on, and enjoy; and the "Gather your own parts and build your own custom beast." type. It sounds like you wouldn't be interested in the first type, so here's what I've gathered about the second. First, the community seems to be really into scale warship replicas... and seem to consider anything else quite toyish. Second, it seems like of any of the RC stuff out there, subs will be among that fastest to get pricy. If you look at the places out there that offer shells, you will find that a fiberglass shell (that's just that outside covering, nothing sealed, no guts whatsoever) will probably cost you more than $100. Apparantly there is a plastic model out there (like that ones you cement and put on display) that works decent as a shell, too. (that'll still cost you a bit) From there, most people buy water tight compartments (WTC's) which are basically tubes with o-ringed endcaps to put the main guts of the subs from. From there, it's up to you to collect all the different part you will need from wherever you can find them and build your own custom ship.

I'd say that it's not for the faint of heart- if you've never done modeling before, building an RC sub will be a really hard place to start. Like I said, I'm just getting started, so good luck with it all.... I'm hoping for the best myself.

[bghost4]

I also would like to build my own sub. I am concerned about motor types and sealing. I know lots of kids bathtub toys don't have sealed motors, so do you need to seal the motors? My goal is to make a simple sub for checking out underwater areas. I need to find a CCD module for taking pictures. I am hoping to keep it under 2 cubic feet in size, hopefully I can find a good powersource to put onboard, I was thinking rechargable sealed battery. But before I do that I have to figure out what kind of motors to use. can anyone give me any suggestions?

[Rex R]

one could check out us plastics for clear pvc and/or clear acryllic sheets. (guessing here) if your cylinder is otherwise airtight, then an o-ring on the prop shaft might work.

[CG Bob]

The best place to look is at theSubCommittee (http://www.subcommittee.com/), there is a discussion board there, where all these questions have been answered. You can generally expect to pay betwen $650 and $1200 US dollars for the parts to make an r/c sub.

For starters, here is a list of the minimum requred items: radio, at least 4 channel; 3 servos; esc; sub hull; watertight cylinder; motor, generally 540 size with a gear or belt reduction, usually 3:1; watertight pushrod and prop shaft seals; battery; charger; swim mask, snorkel and fins (for WHEN, not IF, you lose the model).

Subs fall into two general categories. Dynamic divers use slightly higher than scale speed, and sometimes slightly oversize control surfaces to "drive" from the surface to submerged mode. If you low the sub down while submerged, it will float to the surface. Dynamic divers always have positive buoyancy.
Static divers use a ballast tank to dive. There are several methods of filling and emptying the ballast tank; compressed gas; pump tank; piston tank; or use of a blood pressure cuff (RCABS). In a compressed gas boat there is a small cylinder that contains the compressed gas, usually air brush propellent. A servo opens the vent valve at the top of the tank, allowing it to fill with water. The same servo also opens a gas valve, that lets the gas out of the small tank forcing the water out of the ballast tank. In a pump tank system, a reversible pump is used to flood and empty the ballast tank. The pump out the tank, the sub must be at periscope depth as the scope is the vent for the ballast tank. In a piston system, a plunger moves back and forth in the ballast tank, drawing water in or forcing it out - think of a hypodermic needle. The RCABS boat has a small blood pressure cuff in the ballast tank and a small air pump. Removing the air from the BP cuff floods the tank with water, The air is pumped into the dry section of the watertight cylinder.

I have two operating subs with watertight cylinders or WTC. The 3" WTC has three compartments. The forward compartment is the battery space and holds a 7.2V NiCd or NiMh battery and the esc. The forward battery compartment is connected to the after electronics compartment by a brass tube and O-rings. The center compartment is the ballast tank and has a small cylinder for the compressed gas. The gas cylinder isilver soldered from copper tubing and caps. The brass tube connecting the battery and electronic compartments runs thru the ballast tank. The after space holds the receiver, motor, 3 servos (rudder, dive planes, and ballast tank), Sub Safe, and auto pitch control. The SubSafe is a failsafe device, the will move the ballast ank servo to blow the tank if a raio signal is not received in a set time frame. The auto pitch control (APC) helps keep the dive planes on an even keel. The SUbSafe and APC are connected between the receiver and their respective servos.
The 3.5 inch WTC is similar, but has two compartments. The forward compartment is the ballast tank. The after compartment houses all of the electronics, except the battery. That sub uses a 12V gel cell, which is located in the wet section of the hull. The aft bulkhead has two thru hull fittings that the battery wires conect to.

[Matty G]

There is some info on the net but when it comes down to micro electronics you gotta figure it out for yourself. Look for 'fail safe' devices as these will solve the over-range/over-dive probs. As for the best camera device then go for CCD camera's and at least 800mW output to penetrate the water.