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General control line discussion => Open Forum => Topic started by: Gerald Arana on August 29, 2020, 07:57:33 AM

Title: OS FP, FSR
Post by: Gerald Arana on August 29, 2020, 07:57:33 AM
I know what FIRE stands for (front intake, rear exhaust) but what does "FP" or FSR" stand for?

Does anyone know?

Thank you, Jerry
Title: Re: OS FP, FSR
Post by: Mike Ferguson on August 29, 2020, 08:47:52 AM
FSR: Front Intake/Side Exhaust/Rotary Valve

Not sure about FP.
Title: Re: OS FP, FSR
Post by: David Hoover on August 29, 2020, 10:16:04 AM
Front intake/Plain bearing?
Title: Re: OS FP, FSR
Post by: Gerald Arana on August 29, 2020, 11:11:28 AM
Mike and David, that sounds about right! I forgot about the plain bearing.

Motorman, It's got to stand for something.....

Thanks for the answers guys.

Cheers, Jerry
Title: Re: OS FP, FSR
Post by: Brian Hampton on August 29, 2020, 09:11:51 PM
What makes things uncertain is that, before the FSR, OS had the 40 SR which was their very first Schneurle ported engine (maybe why the "S"?) and it was intended for Racing (rat race and/or pylon) but it was also Rear induction. My bet would be on Schneurle ported Rear induction as indicated by the SR under the exhaust port. I think it was about 2 years later that the exact same crankcase casting was used to make a front induction version which was then called the FSR where the F could only have meant Front induction and the R was simply a carry over from using the same crankcase. FSR then became common for all similar designs of different sizes. Later still there was a small range of rear induction engines called RSR, mainly for either marine or ducted fan use.

Front induction and plain bearing sounds logical for the FP series but where does that leave something like the FX or LA? I'm guessing only the factory knows and they're not telling :).
Title: Re: OS FP, FSR
Post by: John Rist on August 30, 2020, 01:51:21 AM
Not sure where the thought came from but I thought FSR meant Front Schneurle Rotter.   I bought new, around the time it first came on the market, and still have an OS Max 50  FSR.  Flew it on a Dirty Birdy 40.
Title: Re: OS FP, FSR
Post by: Steve Helmick on August 30, 2020, 07:53:42 PM
So....what does the "LA" stand for on the fab LA series engines? "Lay About", maybe?  LL~ Steve