How To Make The Submarine Dive

There is many differnet ways to make a model submarine dive. The follow information go ito the different systems you can use with the benfitts and negetives of each

Please click on each tab to open for information about each system.

Dynamic Dive

Dynamic Diving

To understand the problems associated with the hydroplane operation it is probably best to give a brief description of how the full size submarine works. When a submarine starts to dive, the fore planes are set to dive and the rear planes are set to surface, this has the effect of pushing the bow down and the stern up. Once the submarine has started to dive then the rear planes are also set to dive. When the operating depth is achieved both sets of planes are set level.

To surface the fore planes are set to surface and the stern planes set to dive, this pushes the bow upwards. Once the submarine is angled upwards the rear planes are also set to surface. There are different ways you can operate the hydroplanes according to the type submarine you have and your own preferences, they are:-

1) Fore planes only operational, rear planes fixed

2) Rear planes only operational, fore planes fixed

3) Both planes set to work together from one servo. (Both linked to dive and to surface together or either one set to dive and the other to surface alternately)

4) Both planes set to work independently using separate servos(Skill is needed here to control both sets of planes while diving).

In some cases, one set of planes are radio controlled by the operator and the other set controlled by an automatic leveller, a sort of autopilot to keep the submarine level.

Dynamic diving model submarines use the diving fins to submerge and surface, the electronics are kept dry in a watertight container. Hatches with watertight seals allow access to charge batteries, change receiver crystals and general maintainence.

VENTED TANK (Open tank with water pump)

This uses a reversible pump to fill and empty a top vented ballast tank, when the tank is full of water the submarine should have the decks awash and can be dived as a dynamic diver. When surfaced the pump can empty the ballast tank to bring the submarine to the normal surface waterline.

A diaphragm pump cannot be reversed due to the internal valve arrangements. So remember to use a geared i.e. fuel or water pump.

ADVANTAGES

Ideal system for beginners, easy to operate. Quick and easy to build, easily available parts. Positive buoyancy returns the boat to the surface on loss of power or radio signal. Better scale waterline when on the surface than a dynamic diver.

DISADVANTAGES

Can use more battery power and faster speed to drive the sub under. Large diving planes can give a non scale appearance. May be difficult to maintain a constant depth.

Water Sealed Tank

A heavy duty water car windscreen washer pump can be used as the pump.

ADVANTAGES

Can dive vertically without any forward speed.

Depth control can be more accurate.

Can be trimmed to a proper scale surface waterline.

A fail-safe can be fitted to open the valve if the radio signal is lost.

DISADVANTAGES

Parts are a little more expensive.

A stronger storage vessel is required for the higher pressure air.

The high power pump may reduce battery life.

AIR BAG SYSTEM (As Used On DARNELL Models)

This uses a model steam engine, driven by a small electric motor as a simple air pump to inflate and deflate an air bag. When the bag is deflated and the air pumped into an air reservoir the submarine dives, the pump can be reversed and the bag re-inflated to increase the buoyancy and surface the submarine.

ADVANTAGES

Can dive vertically without any forward speed.

Can be trimmed to a proper scale surface waterline.

A fail-safe can be fitted to inflate the air bag if the radio signal is lost.

The slow pump can be upgraded to a compressor at a later date.

DISADVANTAGES

Slow to dive and surface due to the type of steam engine type pump.

If the battery fails the pump will not operate to surface the boat.

If the air bag splits or the connections leak the air will be lost.

If the air bag is not centrally placed it may be difficult to trim.

Air Compressor System

This uses a compressor to remove the air from the top of the ballast tank, the tank is vented at the bottom to allow water to enter and dive the boat. To surface the boat a valve is opened and the stored compressed air forces the water back out of the vents at the bottom of the ballast tank.

INFO

A car tyre inflator can be used as a cheap compressor, Do not use pet shop fish tank type valves as these can stick with pressure.

ADVANTAGES

Can dive vertically without any forward speed.

Depth control can be more accurate.

Can be trimmed to a proper scale surface waterline.

A fail-safe can be fitted to open the valve if the radio signal is lost.

DISADVANTAGES

Parts are a little more expensive>

A stronger storage vessel is required for the higher pressure air.

A water sensor must be fitted to stop the compressor sucking water in.

If the compressed air is stored within the battery/electronics compartment the high moisture

level may affect the electronics.

Piston & Cylinder Tanks (As used on ENGEL models)

This system uses geared motors to drive a pair of pistons up and down cylinders. To dive the motors drive the pistons inwards drawing water along the tube and compressing the air in the central watertight tank. To surface the motors are reversed and the pistons push the water back out of the tubes. Micro switches are fitted to cut off the power to the pistons at the inner and outer limits of travel along the tube.

INFO

If you have a lath a set of pistons dive tanks can be made from a pair of tubes, a couple of discs with O rings fitted, threaded drive shafts and some geared drive motors.

ADVANTAGES

Can dive vertically without any forward speed.

Depth control can be very precisely controlled.

Fore and aft trim can be easily adjusted if motors are separately controlled.

A fail-safe can be fitted to operate the motors if the radio signal is lost.

DISADVANTAGES

Parts are expensive.

Strong storage vessel required for the higher pressure.

If the power is lost the motors will not operate.

Bellows Tanks

This system uses geared motors as for the piston diving tanks but with a pair of car steering rack gaiters as bellows to form the airtight seal. To dive the motors drive the bellows inwards compressing the air in the central watertight tank. To surface the motors are reversed and the bellows push the water out. Micro switches are fitted to cut off the power at the inner and outer limits of travel.

INFO

A threaded drive shaft and geared motors can easily be obtained but remember to securly seal the ends of the bellows well to prevent air leaks.

ADVANTAGES

Can dive vertically without any forward speed.

Depth control can be very precisely controlled.

Fore and aft trim can be easily adjusted if motors are seperately controlled.

A fail-safe can be fitted to operate the motors if the radio signal is lost.

Easier and cheaper to build than a piston diving tank.

DISADVANTAGES

Strong storage vessel required for the higher pressure.

If the power is lost the motors will not operate.

If the bellows wear or are punctured the air is lost.

Gas System

This system is based on a full size submarines diving system.

The submarine is kept afloat by a gas filled ballast tank. This tank is open at the bottom to allow the water in when the vent at the top is opened to let the air out. When this happens the submarine then submerges. To surface we close the vent on the top of the ballast tank, then open a valve to feed in pressurised gas or air from an on-board pressurised container. This forces the water out of the bottom of the ballast tank. The model then surfaces.

All the pipework joints, valves and seals must be pressure tested for safety.

ADVANTAGES

Can dive vertically without any forward speed.

Small in size and scale in operation.

Very reliable once it is properly set up.

A fail-safe can be fitted to operate the valve if the radio signal is lost.

DISADVANTAGES

Valves are not easily available but some may be made on a small lathe.

Plumbing and setting up the system can be a nightmare.

Can work out expensive to keep purchasing gas refill bottles.

Caution must be taken if using an explosive gas (Butane, Propane).

A strong gas storage vessel required due to the high gas pressures.

Once the stored gas is used up the boat can dive but it will not surface.

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