Crank shaft thread?

It's either an M5 which is metric, or it is 7/32-32 SAE. OS used those two sizes for crank shaft threads on their .15 size engines.

The OS web page shows M5.

Dr.1 Driver "There's a Hun in the sun!"

M5 relates to the current LA series only. The earlier MAX FP and the even earlier MAX cross flow series with a strap on muffler were U7/32 - 32

regards Alan T. Alan's Hobby, Model & RC Links

What is the thread size on the OS Max 15 engine? I need to add a weighted hub nut but cannot find the proper thread size. snipped-for-privacy@aol.com (broke=not working, retired=not working, retired=broke)

Weighted hubs on the business end of a motor in order to balance an aircraft is not a good idea imo, due to gyroscopic precession forces it introduces, and the extra stress on the crank if the balance is even slightly out.

Hey, y'll did great! Thanks much snipped-for-privacy@aol.com (broke=not working, retired=not working, retired=broke)

Correct, I read the wrong line. The proper thread IS 7/32-32. Dr.1 Driver "There's a Hun in the sun!"

Never had a problem on my Enya .09 with a Higley weighted spinner. No precession, no vibration, no problems.

Hey Bob, I think I sold that motor to you. Don't you have that thing flying yet?? Steve Boucher

Brokebob wrote:

Not yet, Steve. Long story including lots of out-of-town time and RAIN. The plane is finished but not balanced yet. Seems that heavy spinners are scarce to non-existient so i will have to move the wing back about 3/4 inch. Gonna do that today. snipped-for-privacy@aol.com (broke=not working, retired=not working, retired=broke)

Attach a piece of lead inside the engine compartment.

This is an old timer with the wing right behind the firewall. Weight doesn't have much effect on balance that close to the CG. It is against my religion to add a lot of weight to a plane that is probably gonna be short on power. I hate to do it but that wing is gonna be back a little further even if I have to give up some of the 'old time' free flight looks. snipped-for-privacy@aol.com (broke=not working, retired=not working, retired=broke)

Ok, I understand now.

Hey, if you go with a spinner (plastic or otherwise) Great planes makes

Brokebob wrote: