Antares100

My Feedback: (12)

Hi All. I have a Hobby Hanger OV-10 Bronco (52") and am interested in opinions/suggestions. Do I go with two OS 26 four-stroke engines or 2- .25 (or so) engines. The kit minimum engine size is stated as a .20. I am not looking for 3-D performance, more scale appearance in flight. I lean more toward the four-strokes, but give me your opinion and reasons for your choice.The Bronco will be done up in a US Marine finish, as I am a former Marine.
On one hand, 2 .25 engines would be the cheap way out. They would provide more power (?) and pull more RPMs. On the other, the .26's may sound better and swing a bigger prop I plan on using 3-blade props for a more scale look. I know when using a 3-blade prop you have to go down in size and pitch. But I'[m wondering if a 4-stroke's ability to swing a larger prop may cancel out having to use a smaller prop.
The plane is not built yet, but I may post a build. We'll see. Thanks in advance for any thoughts.

pkoury

My Feedback: (7)

I built one and flew it for 12 years before selling it to a Marine. I powered mine with 2 OS 25FX engines and Macs mini-pipes. To me the high revving 2 strokes on the mini-pipes sound closer to a turboprop than four strokes would.

vertical grimmace

My Feedback: (1)

If you go with the 4-strokes, I would add on board glow for reliability. I have a Saito .30. They also make a Saito .40 that was in the same sized case, The .30 is the same size as the OS .26. Also, way back in the day, when I flew combat, there were guys running the OS .26 with the RC car .26 cam. This gave them a bunch more power. It was just a drop in part.

Of course, the .25 FX is one of the best small 2-stroke engines ever made. It would be the most reliable and the best runner of them all I believe. It it were me, I would go with the .25 FX or maybe the Magnum .25 SLX, which is a clone, and is the engine of choice of the combat fliers now. They are cheaper and just as good. Check Hobby people for pricing.

Antares100

My Feedback: (12)

pkoury and vertical grimace, thanks. As far as pipes are concerned, don't they provide the most power only at a particular setting? I was thinking of an OS .25 but will look into the Magnum. Another reason I was thinking 4-strokes is that it is easier to hide the exhaust.

vertical grimmace

My Feedback: (1)

As far as the OS .25 goes and a pipe, we used the mousse can mufflers and the quarter wave, Jett mufflers. They all do basically the same thing. I would not think a full tuned pipe is practical or even wanted on a model like this.
As far as the mousse cans and Jett mufflers go though, They will get your .25 up to 19,000 rpm, with the right 9-4 prop. Most used Master airscrew black props. The engine must be allowed to turn up rpm to get on the can. So a reduction in prop load is needed.

My recommendation: Run a stock OS .25 FX with the black Macs mufflers. THey are one piece, and have a low profile so will be unobtrusive to the looks of your scale model. The engine will want 9-5 APC props and they should spin around 16,000 rpm. This is a great set up. Very reliable. In fact I am scratch building a sport twin model right now with just these engines. A Dick Sarpolus 50 Caliber. Looks like a Kaos with 2 engines. It is a practice plane to help me get my feet wet with twins as I have never built/flown one. My goal is a larger German heavy twin fighter.