JollyPopper

My Feedback: (6)

Many folks believe that the FSR line of OS engines is among the best, if not the best, ever produced by anyone. I have a .60FSR that I bought new in 1974 on the same day that I bought a new Kraft Series 74 radio. I still have the engine and it still runs strong. My idea of FSR engines are the ones with bolt on front covers, ie, a two piece crankcase. I also see the .50 size FSR engines for sale that have a one piece crankcase. Are these engines of the same quality as the two piece engines? There should be some OS experts out there who have opinions on this subject.

Iflyglow

My Feedback: (79)

They were a good engine, but are nowere near the best engine ever made.

jeffie8696

Ihave not owned and or tested all the engines around but the OS40FSR is one of my favorites. it stands for Front intake , Schnerule port, rotary valve. I do believe. And that could apply to most modern airplane engines.

MJD

My Feedback: (1)

No argument here, the FSRs are classics and really fine quality sport engines. I'd still like to see those folk's opinions after they ran one side by side something like a Sport Jett darn-near-anything, an OPS Super .60, or a host of other engines that I would compare feature by feature with them any day with confidence. It's not a contest, just saying that people's viewpoints regarding "best" tend to be somewhat personal and can be jaded by the pride-of-ownership factor.

I have an OS .15FP that might be the most faithful and reliable little engine I've ever owned. OS has made some jewels in their time for sure.

MJD

jeffie8696

Ihave to agree. MVVS engines have a reputation of being the best idling engines around but mine was horrible!!!! However Ishall not poo poo the entire line for one bad carb, (and the liner but that is a seperate issue).
My FSR is one of the smoothest engines Ihave ever run and for a .40 makes great power ,even if it is a little heavy. I can put up with that.
And my 25FP is a wonderful if somewhat anemic little engine, hauls my Sig Kadet jr around just fine.

JollyPopper

My Feedback: (6)

OK guys, I didn't intend to raise any hackles or start any debates as to which is the best engine ever produced. So, let's assume FSR engines are just run-of-the-mill engines and compare one piece crankcase FSRs with two piece FSRs. No need to compare with any other brand. Maybe all the posts I read about FSR engines being the best ever were by folks selling one. Think so? So are the one piece FSRs as good (or as bad) as the two piece FSRs?

jeffie8696

My OS10FSR was a one piece and it ran great. It was a high rpm power maker if Iremember correctly.

scott17

I would say that most any size FSR of any configuration, fed the proper fuel (castor is nice), would fall in the catagory of an excellent engine. Every one I had was a sweet running, long lasting engine. I figure them to be a benchmark of sorts; any engine that runs as good as an FSR is a pretty good engine.... the rest I can work with...

gzkpez

50 FSR is a sweet engine. I have been told many times that it has better carb then the 40 FSR. The muffler for it is the "same" as your FSR 60 "744" but the mounting holes are dilled closer together. I have both versions of the muffler.

I have a NIB one, and would buy one if given a good price, but it is still a sought after engine so the price is a little high. I like to get the older engines and use them for sport or scale flying.

In hindsight I think the reason the FSR series was so popular was it was the first series be introduced and designed with the muffler in mind and snural porting (not the 10?). They, other then the 10 seem to be long life, with good power and carb. Oh, I did not mean to bad mouth the 10 FSR, I have one that is well worn (repaired many times) and a very nice man gave me a NIB one to replace it. Also, I do not have many NIB engine just 4 or so not meaning to brag above.

Kweasel

My Feedback: (29)

There are several one piece FSRs ; 10, 21, 25, 28, 32, 50, 90/91, and 108. All of them are very user friendly with good power. They really stood out when they were introduced in the 70s. Now they are just average on power but still relatively user friendly. Most of the 61FSR internal parts will fit in a 61SF case that is more durable, thats what a SFN is. The 50FSR is a fine engine but offers no advantage to the cheap engines currently available. A NIB 50FSR is worth more as a collectible anymore.