Used K&B .20 Sportster
 

Recently got a nice used K&B .20 from Saad Mirtza here on the forum (Thank You by the way) . I started it out light because it had not been run in quite a while. Here are the preliminary readings. On Sig 5% nitro 20% castor with an OS A3 plug turning a master Airscrew 9X4 I got 13,900 thus far:D. The engine is begging for more nitro but I wanted to let it settle in a bit before I up the Nitro and get some serious readings. In my experience the Sportster engines love nitro.

RE: Used K&B .20 Sportster
 

Great news. I had a little time ot waste so I adapted a nice OS 40 size muffler to the K&B .20 because of a bad thread in the stocker. No Baffle because the guy that sold it to me was a Dork (sorry venting )! And I tested some props on Sig 15% nitro 20% castor. With an OS #8 plug. All props are Master Airscrew.Here are the results. With the 9X4 from my first test I got 14,500. with a 10X5 I got 12,300 and with a 10X6 I got 10,700. If you run the numbers across a thrust calculator you will see the 10X5 is making 58 mph and 4.32 lbs of thrust. Nary a hint of detonation and it throttled up beautifully on the bigger props. Not too bad for a .20.