Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Scale Model Gas Engines - Hit & Miss - Throttle Governed - Non-Compression – etc => Topic started by: RobA on January 18, 2025, 02:28:47 pm

Title: Re: Retrol HM-01 model engine running on propane
Post by: cheepo45 on January 19, 2025, 11:30:20 am

Nice job! Propane is so much cleaner than liquid fuels. Make sure that you lubricate the cylinder somehow.
 Scott

Title: Re: Retrol HM-01 model engine running on propane
Post by: txlabman on January 18, 2025, 02:36:07 pm

Awesome!

Great to see it running.

Title: Retrol HM-01 model engine running on propane
Post by: RobA on January 18, 2025, 02:28:47 pm

After having success running my Retrol mill engine on propane, I decided to try running my much smaller Retrol HM-01 engine on propane. I used the same gas bag regulator and unmodified carb setup as before. The bag is filled about 1/3 full and that will last 15-20 minutes. The needle valve is opened around 1/4 turn. Its very sensitive; a click either way from the running position will stop the engine. The same with the throttle cap, which has transparent tape over the center hole and is closed down all the way and opened just slightly.
It runs pretty good in the throttle governed mode but not so well in the hit & miss mode. That is because the fuel flow is very low and the hit cycle is quite weak. I will work on that but I think the carb propane inlet would have to be opened up to allow the right fuel mix for full power operation.

https://youtu.be/HW-wzfiPPV8