OS 160 twin - prop ?

[ericb]

Hello, I have an OS 160 twin and I have a prop question. I have the 160 on a 1/4 scale cub. I currently have a 16X6 on it and it flies it nicely, but it will fly at about 3 to 4 clicks above idle. I would like to do normal flying at about 1/2 throttle. Would an 18X6 prop help me achieve this? How about a 20X6? I know you would get lower top RPM's, but would you also get more thrust with the larger diameter? Any help is appreciated.

[Craigsc5]

I owned one of those engines a number of years ago but never used a 16 x 6. The prop that worked for me at the time was a 15 x 10. If I read your question correctly, even with the 16 x 6 at 1/2 throttle you are flying faster than you would like. You might try going down to 10% nitro fuel or less to reduce power to the current prop or look for less pitch. For me the props you suggest are not the answer.

Craig

[ericb]

What plane did you have that on? Was it for speed? The manual suggest from 15x8 to 20x6, so I figured an 18x6 or 20x6 would help in my situation. You are reading my question correctly.

[ericb]

Do you think a 16x4 would work fine?

[zoomer260]

I flew a 15x8 on mine in a Cap 21. It was a heavy prop and I wish I could remember the make. The plane I bought the engine off of was a Cub the first day it flew and I got the engine for $250 after some guy made the Cub owner an offer he could not refuse for the airframe only. One day old FS 1.60 for $250 ! Dang I wish I hadn't sold it.

Anyway he flew it with a cut down 18x6 Zinger. Maybe 1\2 inch removed on each end.

[bosshoss]

I fly my Balsa USA 1/4 scale cub on a OS 160 Gemini II with a Zinger 17 x 6 , it is perfect. Super slo-mo with the McDaniels twin glo-driver and 1800MAH Sub C Ni-Cd. It gets up and goes too.

One flip starts, after proper choking. Perfect ground clearane.

I just flew it yesterday with a camera on the right strut , looking for a friend's plane in the forest.

Zinger 17 x 6 and don't look back .

[ericb]

I will give the Zinger 17x6 a try. What does your balsa USA cub weigh?

[Craigsc5]

I want to wade in with one more thought, looks like you have a prop choice in mind so one more idea won't hurt. I fly a 9C Futaba radio, under the expotential you can dial in a longer travel on the throttle servo which would allow you to adjust where 1/2 throttle would be, I think the 3D guys are doing this for better contol of this function. Your radio may not have this feature but talk to the guys, they maybe can wade in with the idea. The 160 twin is a wonderful engine, a bit oily with the crankcase vent and all, the airplane I flew was about 9 lbs and 80" wing span, the 15 x 10 was perfect, I finally broke the crankshaft doing some hot rodding.

Craig

[ericb]

I didn't think of doing that. I fly with an X9303.

[zoomer260]

I forgot to mention that the guy I got mine from has a 3 digit A.M.A. number and to fly a brand new plane with a brand new engine on a cut down new prop I think he had done his homework.