A Stroud 'chute launcher has a long spring that must be wound up inside its "can". There is a 15/16" hex nut welded on the end of a shaft that winds up a nylon strap to compress the spring. Although a long speed wrench can be used, it isn't easy for one person.
I made a tool for winding up the spring that works quite well. A collection of China Freight stuff can be assembled into a tool that ratchets the spring down easily. I use a 15/16" deep socket with a short 3/8" to 1/2" adapter. Next, I drilled out the threads of a 1/2" hex nut to 7/16", slipped it over a short 3/8" extension and silver-brazed it on.
This deep socket fits over the big nut on the can and a 3/4" box ratchet wrench fits on the brazed nut while a 3/8" ratchet snaps on to the end.
To wind up the spring, the ratchet is turned while the wrench keeps it from turning backwards when the ratchet is turned back for another turn. Cheap & easy.
Regards, Neil Tucson, AZ