Hey Guy's - I am looking to buy a collet for a Dynamight .15 marine engine ,any one know the thread size?
The motor was given to me and I thought I would put it in a Zippkits Jae.12 on my winter build list.
Any other info {prop,pipe lenght ect would be helpfull
Will be running 40% nitro fuel

I know there are lots of other higher HP options out there,thought I would play with this and see what it can do - Thanks Mike

I am sure you could buy an Octura collet that would work look it up.

Most .12-.18's have 5mm threads on the output shaft, the Dynamite should be the same.
As far as props go, a non-lifting prop will make it easier to drive. An Octura X-437 or Prather 215 would be 2 good places to start.
Pipe length varies according to the pipe but usually 8-1/2" from the glow plug following the flow of the exhaust to the widest part of the pipe should get you close.
I've built 2 of the JAE .12's, versions 1 and 2 but not the ultra-light.
Watch which Octura collet that you get was one of the 5mm versions is not threaded, it's made for electric motors. The part numbers tell the story. It'll have the 5MM in it plus what cable size you're using, .125" or .150".

Thank You Ron for you answer,that should get me in the ball park to start out with
Mike

It's a start.
When I began messing around with the .12's, I started with a Trinity/Picco/Nova Rossi which wasn't the fastest one around but it was dependable if not anything. I've still got it 12 years later and still running great. I also run air-cooled as they don't need water cooling, just lopping off most of the heat sinks. It won't be a rocket but you can always upgrade later.
If you need a few tips and tricks on the 'rigger, I can help you out there.

Super Ron - I will drop you a pm when I start the build

OK. It's just a few small things but they do help.