Sterling R-51 engine swap???

[frank mccune]

      Hi Folks:

      I have a Sterling F-51 that is really nicely finished but is powered by a McCoy .35 RH.  With this engine, the plane is quite nose heavy and needs a bit of weight in the tail to get it to balance well.  I would like some input into replacing the McCoy 35 with a ST G20/.23 or a Brodak .25.  The ST has a bit more power than the Brodak and weighs about the same.  Would these smaller engines give better performance than the heavier McCoy?  The F-51 does not have very large wing area thus the question of substituting a smaller and lighter engine.  I have seen the F-51 powered by .35 engines in the past and all I remember was that they were quite swift!

    Suggestion sand/or comments?

                                                                                                                  Tia,

                                                                                                                  Frank McCune

[Dan McEntee]

  Depending in the weight of the airplane, you have several options. I have no experience with the little Tigre, so can't address that. If you could find a McCoy .29, and the model is light enough, that will keep you period correct for power. As for a .25, I have not been overly impressed with the Brodak .25s that I have, and would advise either OS .25FP or OS LA.25 for a modern engine. Bob Whitely won OTS at VSC one year with one of these, powered by a Fox.35, which would also keep you period correct. If it's over 30 ounces, i would go the .35 route, especially if you are just flying for sport.
   Type at you later,
     Dan McEntee

[frank mccune]

      Hello Dan:

      Thanks for the reply.

      The plane weighs 32 oz. sans fuel ready to fly. I may fly well at that weight.

       A friend of mine also is a aficionado  of the old ST G20/.23 engine.  They start very easily and fun very well.  I know that I am living in the past, but they get the job done.  Of course, the newer more modern engines are a bit "better" but the old ST is fine piece of kit.

                                                                                                               Be well,

                                                                                                               Frank McCune

[Steve Helmick]

Stunt rule #1: "Slow the plane with less pitch, load the engine with more diameter or blade area."

I'd think the ST G.20 .23 would work well with 4" pitch or maybe even less. If you need to use a muffler, that might be a problem, but it doesn't sound like you do.  Steve

[Terrence Durrill]

      Hi Folks:

      I have a Sterling F-51 that is really nicely finished but is powered by a McCoy .35 RH.  With this engine, the plane is quite nose heavy and needs a bit of weight in the tail to get it to balance well.  I would like some input into replacing the McCoy 35 with a ST G20/.23 or a Brodak .25.  The ST has a bit more power than the Brodak and weighs about the same.  Would these smaller engines give better performance than the heavier McCoy?  The F-51 does not have very large wing area thus the question of substituting a smaller and lighter engine.  I have seen the F-51 powered by .35 engines in the past and all I remember was that they were quite swift!

    Suggestion sand/or comments?


                Being a "period engine" guy, I prefer the K&B .29 Greenhead on the Sterling Mustang (kit-S-2) and the Sterling Yak-9 (kit s-3 and sister ship to the F-51.  I have to admit though, that the old reliable standby Fox .35 stunt does an excellent job on both of these aircraft.


                                                                                                                  Tia,

                                                                                                                  Frank McCune

[Steve Lotz]

It's too bad the old 3-bolt backplate Fox 25 isn't still around as it would be perfect. Decent oomphff and lightweight to boot.

[john e. holliday]

There are quite a few on EBAY but some think they are collectors items already.   I usually find some at swap meets unless they see me coming and they start jacking the prices up.

[frank mccune]

     Hi Steve:

     I have one of those 3 bolt Fox .25 engines in my "junk" drawer.  It was a great engine until it did its Fox thing and wore out prematurity!  I think that they weighed about 4.5 oz. and had MORE power than the Fox .35 stunt.  Why it gave up the ghost so quickly, is a mystery to me!  It was a great engine on the largest Clown airplane.  It was much better than the Brodak .25.

                                                                                                                          All of the best.

                                                                                                                          Frank McCune

[Steve Lotz]

I have one that I bought new many years ago and it is still ok. I run it on 25% castor with 3% synthetic and usually swing a 9x5 or 9x6 prop.  I do like them!

Steve