How is a Torpedo ejected or launched from a torpedo tube?

Question

Please no websites, unless they're very informative!

Answer 1

Compressed air

This first, successful, self-propelled torpedo of 1866 used compressed air as its energy source. The air was stored at pressures of up to 2.55 MPa and fed to a piston engine which turned a single propeller at about 100 rpm. It was able to travel about 180 metres at an average speed of 6.5 knots. The speed and range of later models was enhanced by increasing the pressure of the stored air. In 1906 Whitehead built torpedoes which were able to travel nearly 1000 metres at an average speed of 35 kts.

At higher pressures the cooling experienced by the air as it expanded in the engine caused icing problems (see adiabatic cooling). This was remedied by heating the air with seawater before it was fed to the engine. Unexpectedly, this increased engine performance further, because the air expanded even more after heating.

Heated torpedoes

This led to the idea of injecting a liquid fuel, like kerosene, into the air and igniting it. In this manner the air is heated up more and expands even further, and the burned propellant adds more gas to drive the engine. Construction of such heated torpedoes started around 1904.

Wet-heater

A further enhancement was the use of water to cool the combustion chamber. This not only solved heating problems so that more fuel could be burnt, but also allowed additional power to be generated by feeding the resulting steam into the engine together with the combustion products. Torpedoes with such a propulsion system became known as wet heaters while heated torpedoes without steam generation were, retrospectively, called dry heaters. Most torpedoes used in World War I and World War II were wet-heaters.

Compressed oxygen

The amount of fuel that can be burnt by a torpedo engine is limited by the amount of oxygen it can carry. Since compressed air contains only about 21% of oxygen, engineers in Japan developed the Type 93 torpedo (nicknamed long lance postwar by historian Samuel E. Morison) for destroyers in the 1930s, which used pure oxygen instead of compressed air and had an unmatched performance in World War II.

Steam

A derivative of the compressed-air torpedo was the steam driven torpedo. It had to be fuelled with superheated steam from the boilers of the attacking vessel prior to launch. This was a disadvantage since it couldn't be stored ready to use.

Wire driven

The Brennan Torpedo had two wires wound around drums inside the torpedo. A shore based steam powered winch pulled the wires which spun the drums and drove the propeller. Such systems had been in use for coastal defence of the British homeland and colonies from 1887 to 1903. Speed was about 25 knots for over 2,400 m.

Flywheel

The Howell torpedo used by the US Navy in the late 1800s featured a heavy flywheel which had to be spun up before launch. It was able to travel about 750m at an average speed of 30knts. The Howell torpedo had the advantage of not leaving a trail of bubbles behind it, unlike compressed air torpedoes. This gave the target vessel less chance to detect and evade the torpedo, and avoided giving away the attacker's position.

Electric propulsion

Electric propulsion systems also avoided tell-tale bubbles. John Ericsson invented an electrically propelled torpedo in 1873; it was powered via a cable from an external power source, as batteries of the time had insufficient capacity.

Germany introduced the first battery-powered torpedo shortly before World War II, the G7e. It was slower and had shorter range than the conventional G7a, but was wakeless and much cheaper. Its lead-acid rechargeable battery was sensitive to shock, required frequent maintenance before use, and required preheating for best performance. The experimental G7ep, an enhancement of the G7e, used primary cells.

Modern electric torpedoes such as the Mark 24 Tigerfish or DM2 series commonly use silver oxide batteries which need no maintenance, allowing torpedoes to be stored for years without losing performance.

Modern propulsion systems

Modern torpedoes utilize a variety of drive mechanisms that include gas turbines (the British Spearfish torpedo), monopropellants and sulphur hexafluoride gas sprayed over a block of solid lithium. Some torpedoes, such as the Russian VA-111 Shkval or the German Barracuda, use supercavitation to increase their speed to over 200 knots (370 km/h); compare the speed of the Mark 46 torpedo, which does not use supercavitation, of about 28 knots (32 mi/h, 52 km/h).

Answer 2

The torpedo is NOT discharged with compressed air. Compressed air is used to fire a ram and the torpedo is discharged using sea water forced in behind the torpedo at the other end of the ram(water ram discharge system). No air leaves the submarine as this would give away your position and would require different discharge pressures at different depths. All water used is external to the pressure hull so torpedo can be discharged at any depth.

Answer 3

The torpedo is blown out of the torpedo tube through compressed air; when it is outside of the submarine, the engine on the torpedo is activated, and travels at a very high speed by way of an alcohol or other fueled engine, to the target.

Answer 4

Sounds like he's not dealing with a full deck. If he's worth his salt, he should take it on board that such action would not be plain sailing and could land him in hot water. Nice to see you back!

Answer 5

Compressed air.

Answer 6

launched with air presure