ORIGINAL: MikeG4936
I am finishing up a new ARF - the 27 oz. Sportsman Aviation Aero Princess. The manufacturer recommends the AP .15 engine for power. The two engines I am debating on for this plane are the Enya .15 IV (circa 1970s), and the O.S. MAX .25 R/C (1973 model). I have already broken in the Enya, and its spinning an 8x4 at around 12500. I haven't run the OS yet... I just LOVE the little Enya, but I'm afraid that it won't be enough since it can't rev nearly as high as a modern .15 can. These engines are both old tech (iron pistons, high castor, etc...) but I'm thinking that the old O.S. .25 will put out the power that a modern .15 can, right? Any thoughts?? Thanks!!!
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I run 7x4 to 7x6 props on my .15 size engines. Even the old ones. These little rascals need to rev up to begin to develop serious power.
I don't know if the .15 will be up to the task of pulling the model because I am not familiar with the model. But you can bet that the lighter weight of the .15 will permit the model to turn sharper and fly better, if there is enough power being developed.
I have an old Fun One that I have flown with both an OS .32F-H and with several .40 to .50 size engines. I prefer flying it with the .32. It is a completely different model with the smaller engine.
Fortunately, the .32 provides enough power to fly rather quickly and will just hover the model. The larger engines provide infinite vertical performance, but they also double the turning radius with their extra weight. I'll take the .32 for power every time.