Hi there,
I am assuming it is a C18/C20. This was used in Bell 206 Jet Ranger, Hughes 500/520, Enstrom 480, Eurocopter 355 Single Squirrel, Bolkow BO105.
If it was a C28/C30 then it was: Bell 206 Long Ranger, Sikorsky S76A.
If it was a C47, it was: MD 600.
There are surely some others that I've missed out, but that should keep you going.