I was figuring that I'd use a .40 LA-S in my Nobler ARF when I get around to assembling it.  But I find myself with four FP-S .25 engines.  Looking through past posts in this section, there have been LA-S .25 Noblers that are said to fly well.  I also read that with the .40/46 LA-S, the plane gets nose heavy, so that's why I was wondering on the .25 FP-S.  Also, I was flying a gimme Flight Streak with a FP-S .25 engine this past weekend.  On 60' lines I was doing 3.5 second laps.  Much faster than my FS ARF with the .25 LA.  I did not find posts by anyone who had flown a Nobler ARF with the FP .25 engine.  Anyone have this experience?

In my opinion not enough engine unless you fly short lines and can keep under 40 ounces.

I agree that an OS 25 FP is really too small for a Nobler ARF. It might pull it around OK in level flight, but struggle in maneuvers or if it is a bit windy.

I have a Nobler ARF. I had an OS 40 LA on it and needed a bunch of tail lead to CG balance. It weighed close to 49 oz and did not fly well.

I came across and picked up the new Enya SS 35 EX BB ABC engine and put it on my Nobler. Wow, what a difference. The Enya SS 35 is designed around a 25-size case and is quite light at 7 oz. A Fox 35, which the Nobler was designed around once upon a time, weighs 6 oz. With this lighter 35 engine (compared to the 40 LA) I was able to remove most of the tail lead. Model overall weight came down to 43 oz all in (w/ stock Enya muffler). The model flies totally different at 43 oz.

I used a 25 LA in Nobler ARF and it flew nicely. 62' x .012 lines and 10x3 APC prop. 10% nitro. Full disclosure, it wasn't a powerhouse and if it was really windy, it was better to leave in the car.

Back when I was flying glow, the secret sauce to a competition Nobler ARF( besides enhancements like tip weight box, adjustable leadouts, equal flaps, upgraded elevator and flap controls and a few more) was the OS LA 46 with the  OS venturi restrictor, Shipp backplate, Smith venturi needle valve/body, ports tipped(although not a must) and a tongue muffler.  The stock muffler is where most of the weight is. An APC 11-4. Not at all nose heavy even with 4.5 ounce tank.  Of course, we replumbed the tank internally and for external air pressure. That combo could fly in sensible wind and grunt aplenty for verticals and overheads .

Quote from: Clint Ormosen on October 03, 2025, 10:59:55 PM
I used a 25 LA in Nobler ARF and it flew nicely. 62' x .012 lines and 10x3 APC prop. 10% nitro. Full disclosure, it wasn't a powerhouse and if it was really windy, it was better to leave in the car.

   I never tried one in a Nobler ARF but I had a similar experience with the ARF Primary Force. Started out with an LA.25 as per instructions and everything set up like the book. It flew right off the bench, but at best was marginal on power. Not a very big model, but weighed in the 43 ounce range, maybe 45 I think when new. After a season, I decided to try the FP-.25 and get some experience with that. It was better, and I'm convinced the FP.25 is stronger than the LA.25, but like you said, it was in any kind of wind where you really had to be careful in overheads and such. One of these days I'll try an FP.25 in something else that may be just a bit smaller and a bit lighter.
  Type at you later,
    Dan McEntee

I ran an OS .25FSR in a Noblarf for a while. The trick was to try to keep it below Mach 0.9 with the right prop. Too much fiddling with props and fuel for different days. Plenty of horsepower, just not as tractable as you might like if you are used to running an OS .46LA. The .25FSR even though an older engine probably has more grunt than the FP, which has in my opinion more grunt than the LA.

I have been happy with a good Brodak 40 in my Nobler ARF

Mark,
You need to setup the OS 25FP like they do for the OS 20FP per Brett Buck instructions. Use the stock 3030 muffler, stock NVA, stock full venturi, APC 9x4 prop, 10 - 15%N fuel. Set the CG at ~16% average chord,

With Brett's setup it will pull the Nobler better than a strong Fox35. Keep the lines to 0.012" cable and ~58' C to C.

Best,     DennisT

Maybe mine was light but I have flown mine happily with a 25FP.

60ft lines A 9x4 prop is too small for the 25FP.

I fly my 25FP with 10x3 APC and 10x4 Top Flite wood. Engine runs in a wet 2 solid as a rock for the complete pattern.

Don't underprop the 25FP with a 9x4 you don't get the power you need.

Tried to send message/pm and response is member unknown/no address/pm.

Sorry.  Just saw this. You talking to me, Doc?

Okay. 'Nuther "what if".  I was going through my engines to organize them and see what to get rid of.  I pulled out an FP-S .35 that I forgot about.  What do Y'all think about that on the Nobler ARF?

Quote from: Mark Mc on June 16, 2026, 03:55:53 PMOkay. 'Nuther "what if".  I was going through my engines to organize them and see what to get rid of.  I pulled out an FP-S .35 that I forgot about.  What do Y'all think about that on the Nobler ARF?

It will pull the Nobler ARF fine. But it's a heavy engine and especially so if you use the OS stock muffler.

I had an OS 40 FP (ABN) on a Nobler ARF, and I needed like 2.5 oz of tail lead to CG balance. And the 35 FP weighs more than the 40 FP (cuz the 40 is basically a bored-out 35). My model weighed 49 oz and flew heavy.

I now am using the new Enya SS 35 EX (BB-ABC) on my Nobler which is quite light for a modern 35. I was able to remove all of the tail lead, and the model now weighs 43 oz where it flies much better.

Enya designed the new SS 35 EX around a 25-size case thus the reason why it is quite light at 7 oz (engine only). About 1 oz more than a Fox 35.

Colin

A FOX 35 with a Brian Gardner ABC set and a Stan Frady tongue muffler will be a great combination. Would work best in a 2-2-2 with like a 10x5 prop or 10x4.5, still needs about 25% total oil for the main bearing and rod.

Best,   DennisT

I'm kinda late for this -- but I was going to recommend a Magnum 36.  I don't specifically have any experience with the FP 35, but if it acts like a smaller version of a 46LA, it'll be perfect.

The Nobler does best in the 40oz range. The ARF is film covered and that saves a lot of weight, you also want to watch the balance point. Since it was designed around an unmuffled FOX 35 putting one of the heavier engines in will likely need tail weight (even a Fox with a standard muffler will require tail weight in the ARF) but the Fox with a tongue muffler will need very little. I think even a standard Fox 35 running 10%N, 26% total oil on a wide ish 10x4.5 or 5 prop in a rich 2-2-rich 2 will pull it very well. Seems we got into this idea that the Fox 35 had to run in a 4-2-4, on a 10x6 prop because that's what the top guys did. The thinking was that it would change gears to pull uphill then slow in the down leg. For the most part that worked with the very light not supper finished stunters way back. As finishing became more important the weight went up and ships got bigger, you needed more power. The tuned pipe changed the thinking a little and so did the 2-2-2 run approach. But the old Fox was still looked at as only a 4-2-4 type motor. When Brian Gardner came out with his ABC setup the very light Fox with that piston/cylinder set up could run with the rest easily in the 2-2-2 and pull those bigger ships better (actually even the original Fox could run in the 2-2-2 just nobody did it).   

Quote from: Dennis Toth on August 05, 2026, 07:50:40 AM(actually even the original Fox could run in the 2-2-2 just nobody did it).   

For long!  Try that if you are last up in first and first up in the second.  You used to get  5 points for starting, that is why!

Ken

Quote from: Dennis Toth on August 05, 2026, 07:50:40 AMThe Nobler does best in the 40oz range. The ARF is film covered and that saves a lot of weight, you also want to watch the balance point.   

Exactly my experience on my Nobler ARF.

On CG, the ARF kit instructions mention a CG of 2.5" from the wing LE at the fuselage. That is where I have mine and it flies well there.

On model weight, the kit instructions call out an OS 40 LA as a good engine for the model. I tried one but needed around 2 oz of tail lead to CG balance. Model was at 49 oz. So, I tried the new Enya SS 35 EX (ABC-BB) which is quite light and it allowed me to remove all the tail lead. Model weight came down to 42 oz and flies much better. So, the Nobler ARF in the low 40's is right on.

The Enya SS 35 EX is quite light for a modern 35 (7 oz) cuz it's designed around a 25-size case, and Enya also used an alum head. In comparison, a Fox 35 is at 6 oz. A 40 LA is at 9.5 oz

Colin

Years ago, somebody convinced me that an FP 25 was a good engine for a Sig Twister.  It went "OK" in calm wind, but I have been happier with a 35 or 40.

I fiddled with a Top Flite Nobler for many years (decades).  I got my best satisfaction with the FP 40.