Lying on the surface

[LUCKYSTRIKE]

You may not be aware but WW2 aircraft engines were also started by cartridges similar to these, known as starter cartridges. Often a spare would be fitted inside the engine in case during a flight it needed restarting. These are often found on WW2 airfields due to there abundant use.

An interesting find.
LUCKYSTRIKE

[big ned]

Hi Lucky,

The early starting system was of the combustion type (Coffman starter) using a multiple breech containing five cartridges (resembling big shot-gun shells and loaded with solid-fuel grains) which were indexed mechanically from the cockpit and fired electrically. The combustion gasses at pressures over 2,000 psi were piped to a starter-unit bolted to the rear face of the propeller reduction-gear housing, which drove the engine through a dog geared to the propeller. The starter unit used a piston driving a ball-jack to convert the piston's linear motion into rotary motion to drive the engine. The resulting power pulse was brutal -- while it powered the engine for less than a full revolution, the speed and energy were high enough that engine inertial would continue to turn the engine for several revolutions. If an engine failed to start after all five cartridges were fired, a detailed inspection was require to check for damage, so a specific starting regiment was followed which addressed priming, clearing and other starting procedures. The cartridge system suited military applications since it was reliable (aside from damage it caused) and could be used in remote locations where support was unavailable, thus eliminating the problem of dead batteries with no means to recharge them.

Later types of aircraft such as the Hunter and Canberra had a cartridge the size of a Bofors shell, and the General Dynamics F-111 we have at Cosford utilises a starter cartridge the size of a 5 litre paint can!!

Regards, Ned.

[OKW]

Yes i had considered the aircraft starter. They were using them at Middle Wallop in the late 70's to start the fixed wing aircraft that the helicopter pilots had to begin their flight training on. Theres quite an art to firing it and getting the engine to catch. You could tell the newbie course they used to sound like machine guns. These starters used shells the size of shotgun cartridges. Stoke Orchard was a glider training base, i don't know if they would have had towing aircraft, and how they were started, or been ground launched by cable.