avionette

Hi everyone
sorry my english limited
i tested a busa 1/6 scale pup with os 46 ax and 11x7 pro zinger prop the model fly great but seems a little underpower when i want to do acrobatic manouvres can you help me to understand well the props caracteristic; if i buy a 12x5 so large diameter and lower pitch the model will reduce power but increase the thrust? and if i put a 12 x 7 what's the difference? and if i reduce diameter 10x 7?
regards

vertical grimmace

My Feedback: (1)

For that engine, I would try a 10-6. I think generally for that airplane I would keep the pitch down. Then try an 11-5 or APC makes that 12.25-3.375 prop that creates a ton of thrust. Try to stick with APC props as well. They just tend to perform better in these smaller sizes.
that 11-7 is too much prop. It has too much pitch for that diameter.

avionette

thank you just now a boy in another forum say that i have big cowl and i have to increase diameter 12x5 or 13x4 wood and light propeller

mgnostic

I agree with the folks who say lose some pitch. I flew a profile Ultimate Bipe with a .46 and a 12-5 prop for several years. It didn't have the big cowl but it does have draggy thick wings. The lower pitch will allow the engine to rev into its power band. With something as draggy as the Pup the 12-7 cant really operate at it most efficient airspeed and ends up just thrashing a lot of air around especially as the plane slows down as you climb into a loop. Think of a high pitch prop as a wing with a high angle of attack. The low pitch/ low angle of attack will continue to make lift/thrust. The 12-7 would work a lot better on a pointy nosed fast airplane. With 12-5 I still had to throttle back in level flight and I think it would have hovered on a 12-4. As far as it goes props are relatively cheap. Grab a couple in different pitches, slap one on, get some altitude, and see how it work. As the say goes your mileage may vary. Part of getting the best performance out of our planes involves trying out some variations.

Wayne22

My Feedback: (2)

I would not go bigger than a 12-5 (the 12.25 x 3.75 is awesome ) the big cowl is not a reason to increase the diameter..I flew a GeeBee Z for a couple of years, and it only had an inch of the prop outside the cowl, and it flew great! You may want to look at the Master Airscrew scimitar props, they have more blade area at the tips (where you need it) and seem to work better in an application like this...................

avionette

hi!
thanks about big cowl ...ok i will buy 12x5 and 12x4 i'll try after 12x4 i see at tower the scimitar prop start from 12x6 they dont have 12x5 just normal master wood prop or zinger
PLEASE ANOTHER INFORMATION .....i see the zinger has large blade and my friend use master airscrew nylon prop (that black ) with the same diameter and pitch but not larger than zinger.
What's the difference from large blade ? can i buy and try apc 12.25x3.75? why do you say awesome?
best regards

Wayne22

My Feedback: (2)

The 12.25 x 3.75 bolted to an OS 46 makes a lot of thrust...it is just a really good combination.

The zinger and Master airscrew props are not as efficient as the APC (or the Master Airscrew scimitar) props, and won't develop quite as much thrust.

avionette

thank you very much so i start with 11x7 zinger ok if i buy 12x6 scimitar wood? after 12x5 apc then 12.25x3.75 for finysh a 12x4 apc tell me if is ok these props?