Crash King

My Feedback: (24)

Dave,
I sent my 53 in for service and your service guys replaced some parts that were defective from the factory. The engine was NIB but sat in the closet for some time. I can only get approx 8500 RPM (backed off a peak of 8900) out of her on a 12x8 Zinger. This seems low, but I saw an article by Clarence Lee and he was only getting 9700 on the 63. I am told this is a low RPM for this prop. Am I dreaming, I have run approx 4 tanks of fuel through the engine. I am running 20/20 fuel.
Thanks

Dave Shadel

A 12x8 Zinger is too much prop for the YS 53. We normally use an 11x7 or 11x8 APC. It should turn the 11x7 at about 11000.

Crash King

My Feedback: (24)

The 11x8 would hit 10.5K plus and the 11x7 was well over 11K.
Thanks Dave, I am surprised I also ran a MAS 12x8 and got even better RPM out of them, almost 10K. Are the Zinger props less efficent or more,
Thanks, I am very happy
Crash King

Dave Shadel

If you take a good look at most any of the currently available wood props, they have square leading and trailing edges, thick airfoils and inconsistant grain structure from one blade to another. It's not a knock on the wood prop manufacturer, it's just a fact of life with the material they have to use. The plastic props have better and more consistant airfoils, sharp entries and exits and are just better from an aerodynamic standpoint. We used to rework the wood props for better performance before the advent of good plastic props, now it's just a lot easier to get the performance without the rework headache.
Sounds like either the 11x7 or 11x8 will work fine. If you want a lot of vertical, you might also try a 12x5. Anything that keeps the peak RPM at 10500 to 11500 will work fine.
Good Flying,
Dave