Depends what you mean by "successful" ..... but I think the answer's a Bell anyway.
Jet Ranger/206/Kiowa has a lot going for it, but was not the Huey/205/Iroquois and variants the biggest production run, making it the "rotary DC-3".
You could also argue the case for the Bell 47, as the first mass produced rotary that could actually do a job (a contentious claim perhaps??)
And on a personal note I'm very pleased to have qualified on all three (amongst others).........hence the handle
