titaniumbird00 has about the best answer except the starter was invented and was in operation on many A/C of the time. The "shotgun" starter is utilitarian, and weight saving (starters are heavy). The B-57 Canberra was one Bomber which had the Cartrige start
They weren’t shot shells, where you’d have a projectile, it was just a little explosive charge to turn the engine over. This was before the time of electric start and the engine was too big to just throw the prop to kick it over or crank it by hand.
The charge would not be the source for ignition as someone else mentioned. If anyone finds it, I’d love to read about though, I know they used this method to start large engines back in the day.
Also, I’ve seen big bulldozers where there was a small 4cylinder car engine (pony engine) bolted to the huge diesel engine that’s sole purpose was to start the larger engine.
Electric and air starters have come a long way since.
becuz they dont have the equipment to make keys, and WWII planes doesnt need keys. They spin the propeller (only to speed up the starting) and the shotgun shells is made to start the fire in the engine.
and its not really shot gun shells cuz if it is the gun will be bigger, its just a small gun to start a fire thats all.
I haven’t seen Flight of the Pheonix, but I do have an aviation background.
Black powder charges have been used to start aircraft engines in an emergency deployment, (when there wasn’t time to connect a GPU if a battery was dead,) since WWII.
A 12 ga. cartridge provided enough energy to kick a radial engine that had been properly primed through enough that it would begin to catch and run. A coffee can sized charge was used to start the #2 engine of the B-52B’s during the cold war in the event of a sudden deployment; it’s combustion provided enough expanded gas to spin the engine up to the "come in" speed where it would come up to idle on its own.
I don’t recommend trying to start the O-200 in your Cessna 150 this way.
If I recall the movie’s premise well, a shotgun shell may have been used because electrical power wasn’t available according to a plot that directors wanted to make as realistic as possible, and would have been plausible for old radial engines flying in the third world.
It’s called a cartridge start. They can come in various sizes and are used whenever the normal method of cranking the engine is not available (dead battery, etc.) As another poster said they used a large canister charge to start some jets. This was done in the event that an air source was not available. Reciprocating (piston) engines use a gear driven electrical starter for a normal start. If the battery is dead, you use the cartridge.