Description
Object description
Description of and preparing Mk 12 torpedo fitted with air rudder control gear for use.
Content description
Reel 1: Opening scene of Beaufort being armed with 18" Mk12 torpedo fitted with air rudder control gear. 4 cylinder burner engine similar in principle tot he semi-diesel type. Mk12 made up of six compartments. Warhead, air vessel, balance chamber, engine room, buoyancy chamber and tail. Sectional drawing of torpedo and description of the six main parts. Warhead charged with 445lbs of TNT, Nose fitted with pistol charge which on contact with target fires into the TNT charge. Air vessel is charged with air to a pressure of 1600lbs per sq inch. Air used to drive various components of the torpedo such as gyroscope and servo motor and also mixed with the fuel that drives the engine. The balance chamber has depth regulating gear which operates the horizontal rudder which controls the depth that the torpedo runs at. Close up of depth regulating gear and detailed description of gear.
Content description
Reel 2: Torpedo 4 burner engine being removed from the balance chamber. Engine produces 220hp at 20 knots and 48hp at 27 knots – water cooling using sea water. Runs on shale oil. Explanation of operation of engine. Description of operation of gyroscope housed in the buoyancy chamber and effect on rudder operation to keep torpedo running straight. Demonstration using diagram of trajectory for dropping torpedo from aircraft – should enter water at 3˚ nose up to trajectory. Attitude of torpedo is controlled by drum control gear and rudder control gear connected by cables to torpedo until it has cleared the turbulence below the releasing aircraft. Explanation of air rudder operation to counter oscillation of torpedo in flight. Air rudder breaks off once torpedo enters water. Action of propellor described. Counter rotating props used to overcome torque reaction of single propellor.
Content description
Reel 3: "Air, fuel and oil leads." Diagram illustrating various components of Mk12 Torpedo and various pipe leads connecting them. 4 kinds of pipe lead – those carrying high pressure air, low pressure air, fuel and lubricating oil. Process of preparation of torpedo for action explained and various stages of activation of torpedo valves etc.
Content description
Reel 4: "Preparation for running" Known as charging and adjustment or "C&A" - first step is to fit gyroscope, next is buoyancy chamber test, tail oil strainer is cleaned as is engine oil strainer. Fuel bottle is filled as is lubrication oil bottle. Warhead is fitted and various adjustments made to valves etc. and charging air vessel.
Content description
Reel 5: "Checking Rudders" - to ensure torpedo will run at correct depth. Fitting igniters to generator and priming. Shell of torpedo is oiled to prevent corrosion and check all valves and panels etc. are secure. Loading torpedo onto Beaufort. Primers and pistols are fitted before torpedo is winched onto aircraft. Air rudder is fitted (and wind vane). Drum control wires are attached to aircraft and pilot checks torpedo and ensures stop valve is open and safety fork removed from pistol. Aircraft takes off.
Physical description
35mm