os 70 surpass II RPM

Jeez, what is wrong with this picture?

No, I did NOT say that. In fact I HAVE tried more nitro and found the result wanting in light of the added expense. Not significantly better idle or transition to what I already had, and not enough more power to justify the added cost. I was not brought up to waste resources or throw money away, so I CHOOSE not to run more nitro. Can I say it any other way to make it clear for you?

inexpensively.

requirements

Reply to
Six_O'Clock_High
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Nothing wrong with this picture. You are just in the vast minority concerning nitro and four strokes.

performance.

Reply to
Paul McIntosh

Add me to the vast minority. I use 10% nitro and have great idle and transition. People are always asking me how I get my engines to run so well. I don't know.

John VB

Reply to
jjvb

Slow down the idle! There are adjustments for that and they work real well with higher nitro.

Reply to
Paul McIntosh

I am a newbie to the 4-stroke engine and I have a OS FS-70 Surpass II.

I am putting it on a Sig Something Extra and I wanted to know what pro size I should use.

Thanks,

Joh

-- Manny515

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Reply to
Manny5150
13-6 or you can go with a 14-4
Reply to
Double Ace

agreed 13x6 for this engine

12x8 or 14x4 alternatives if for some reason you do not want 13x6
Reply to
Charlie H.

I'd try the 14x4. I flew a Somethin' Extra for 4 years and found out that the more torque the better and it isn't gonna be fast no matter what pitch prop you put on the front. Somethin' Extra's main virtue is it's ability to fly slow and almost stallproof. It's a waste of time to try to push an airfoil that thick to a high speed! I love flying this kind of plane myself. Land it and watch the rollout... all 2 feet of it. Takeoffs required 6 feet, but that was with a 2 stroke. Your 70 should do better.

Jack

Reply to
Jack Sallade

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