The shells were manufactured in 1943 and still work!
How it’s done:
The Coffman starter uses a specially made 4 gauge paper shell with an electric primer. It is filled with .25″ and .187″ diameter cordite pellets for slow burning powder. The shell fires into a starter assembly on the accessory case of the engine, same position as an electric starter. It DOES NOT fire directly into a cylinder of the engine. The gasses force a piston inside the starter assembly forward towards the engine collapsing spiral gears on top of each other converting it into a circular motion. This engages the starter dog and rotates the starter gear. After the piston reaches the end of its travel a valve released the residual pressure and a die spring resets the whole process.
Wow that’s really cool. I really want to read more about war planes and other vehicles someday… such interesting history.
Such an awesome / timeless design.
Thoughts? Any of you guys thinking of modifying your Honda Civics to take a shotgun start? :P Now that I know about this method, I feel like turning a key or pushing a button is so lame.
Gat tip: Jay