OS 55 and 15x4 Zinger Pro
 

OS 55 and 15x4 Zinger Pro Engine has been broken in using OS proceedure; with about 6 flights
of about 5 min duration. I think it was set up a little richer than normal. Obtained 8900 but very
sure it will be higher when fully broken in. It is mounted on an Sig Kadet Senior Arf with a
Dave Brown mount. Took a fair amount of filing on various places to get it to fit.

RE: OS 55 and 15x4 Zinger Pro
 

Wow thats a lot of prop. Unless you are trying to keep the prop noise down, there may be a better prop. Allow me to suggest some comparison data:

......type..........size...........RPM..........HP .........lbs. Thrust cor. for fuse drag.......Pitch speed MPH..........................Muffler

-Zinger Pro----15X4-------8,900------.91--------------------7.07--------------------------33.7-------------------Stock /w baffle
----APC-------12X5------12,900-----1.44--------------------7.90--------------------------61.0-------------------Stock /w baffle
M.A. (S-2)----12X5------13,800-----1.40--------------------7.74--------------------------65.3-------------------Stock /w baffle
----APC-------12X5------14,600-----2.09-------------------10.12-------------------------69.1---------------Jett Stream muffler

Static, on the ground numbers.

Note the near double pitch speed with another prop.

RE: OS 55 and 15x4 Zinger Pro
 

If you want performance you better not follow OS`s advice on props, they always advice WAY to big props. You have your engine struggling with a too big propeller and may possibly fry due to heat build up. It would be much happier if allowed to rev 10K and upwards

RE: OS 55 and 15x4 Zinger Pro
 

Way too much prop 8900 is way to low for that engine

RE: OS 55 and 15x4 Zinger Pro
 

The 55AX does seem to be very happy at 10,000 rpm, dont think I would run it any lower.