Starting Aircraft With a Shotgun Shell?
YouTube / Johnny Johnson
Did you know that a starting system used on many piston engines in planes and armored vehicles back in the day was a shotgun shell? This is known as the Coffman engine starter, or simply known as the shotgun starter.
A shotgun shell was a surprisingly common way to start an engine during the 1930s and 1940s.
Special shotgun cartridges were used as a common cordite explosive that was utilized to start tractors, tanks, and most commonly, aircraft with radial engines like the famous F4U Corsair.
There are various starter systems using shells, but they’re typically called Coffman engine starters. On planes, shotgun blast pressure pushed a special piston which drive a screw thread, engaging with the engine, turning it over.
Meanwhile, on a Field-Marshall tractor, the shotgun blast pressure acted directly to drive the engine piston sending it through its stroke and bursting the engine into life.
Shotgun starters are surprisingly simple. They offered advantages for the expensive planes that used them. To operate, a cartridge is inserted into a breach which is connected to the motor by a short steel pipe, which is quite similar to a gun barrel.
The pilot then fires the cartridge from the cockpit and high-pressure gas shoots down the gun barrel, forcing the plane’s motors to spin and engage the starter ring gear on the engine which is attached to the crankshaft. It’s also compact and lightweight- not needing any special auxiliary equipment.
However, the primary disadvantage to shotgun starting is that for each attempt to start the engine, a new cartridge must be used. To negate this disadvantage, an air compressor starting system could be added to engines already equipped with shotgun starters.
Shotgun starters can also be added to planes as an additional feature, such as quick takeoffs. They’re most commonly seen in American planes with radial engines like Pratt and Whitney wasp engines. British WWII fighters also had variants equipped with shotgun starters including the Supermarine Spitfire and Hawker Typhoon.
Technological advancements after WWII such as the use of electric starters caused the decline of shotgun starters.