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I'm new to the PB stuff, but have been flying giant scale RC planes for years.
Specifically, Pylon racing airplanes.
Last year I wrapped up a project that might be helpful to some. I have a plane called a Sundowner. It's got an 80" wingspan and uses a 2.10 cid rotary valve single cylinder 2S made by a company called Moki.
Engine is around 35cc and rated at 5hp on 10% nitromethane glow fuel.
The prop I wanted was a 16"x16 pitch. The stock engine was able to turn it to a peak ground RPM of 7400.
After extensive modification (new head, a water "coil", radiator, full wave tuned pipe, new RING (the point of this) and some other stuff), I was able to get the same prop up to 11,500rpm on the ground. In the air its unloading prolly another 900-1200 rpm for a peak of 12,700.
That's a theoretical ground speed of over 190mph! The plane does nowhere near that due to drag on the airframe, but it's safe to say that it definitely hauls the mail. It's been radar gunned at over 150mph during straight and level flight. This is a 80mph increase over the stock engine.
Not too shabby.
Frank Bowman is an old man that lives down in New Mexico. Frank is a sharp ol cat and machines scratch built piston rings for RC engines. His rings are legendary in the gas/big displacement RC airplane community. He made me a ring for the Moki engine and it responded really, really well.
You can find Frank by just Google foo-ing his name along with piston ring.
His stuff is affordable and it WORKS!
Maybe this will help someone with an engine project.
Here's a YouTube of the Plane/Engine:
http://www.youtube.com/watch?v=MWDosPup5L0
Specifically, Pylon racing airplanes.
Last year I wrapped up a project that might be helpful to some. I have a plane called a Sundowner. It's got an 80" wingspan and uses a 2.10 cid rotary valve single cylinder 2S made by a company called Moki.
Engine is around 35cc and rated at 5hp on 10% nitromethane glow fuel.
The prop I wanted was a 16"x16 pitch. The stock engine was able to turn it to a peak ground RPM of 7400.
After extensive modification (new head, a water "coil", radiator, full wave tuned pipe, new RING (the point of this) and some other stuff), I was able to get the same prop up to 11,500rpm on the ground. In the air its unloading prolly another 900-1200 rpm for a peak of 12,700.
That's a theoretical ground speed of over 190mph! The plane does nowhere near that due to drag on the airframe, but it's safe to say that it definitely hauls the mail. It's been radar gunned at over 150mph during straight and level flight. This is a 80mph increase over the stock engine.
Not too shabby.
Frank Bowman is an old man that lives down in New Mexico. Frank is a sharp ol cat and machines scratch built piston rings for RC engines. His rings are legendary in the gas/big displacement RC airplane community. He made me a ring for the Moki engine and it responded really, really well.

You can find Frank by just Google foo-ing his name along with piston ring.
His stuff is affordable and it WORKS!
Maybe this will help someone with an engine project.
Here's a YouTube of the Plane/Engine:
http://www.youtube.com/watch?v=MWDosPup5L0