Got several hours to play around with my .46 today and had a great time. I didn't get to try every combination in the book but I tried all I could before the neighbors started staring and making evil faces.
First the 10% nitro (SIG of course and 20% all castor) posted a best of 13,570 on the same MA 11X6 prop as the beginning of the test. That is good for 77.1 mph and 7.7 lbs of thrust.
Today I tried my same SIG blend only 15% nitro . I dialed it in with a Fox standard plug and another head shim, on the 11X6 it gave me 13,320. A few rpms shy but it gave me some breathing room for the rest of the testing. Still good for 75 mph and 7.42 lbs thrust.
Next up with the same setup came a Master Airscrew 10X6 that gave me 14,400. No surprise. 81 mph and 5.92 lbs.
I stumbled across an old Rev Up wooden 12X5 and thought hey why not, this thing has lotsa grunt. WOW gave me 11,600 ! that is good for 54.9 mph and a whopping 7.97 lbs of thrust. And it just seemed to turn that prop over so easy. ALMOST 8 LBS OF THRUST !!! FROM A .46!!!![X(] AND AT OVER 50 MPH!!
Next I went to the opposite end of the spectrum, this is where I fell into some difficulty. on a Master Airscrew 9X6 it turned a relatively steady 16,500 . Pretty good numbers but I wanted more. Still 93.75 mph and 5.1 lbs is a feat no other engine in my airdrome can match!
This is where I experienceD some detonation issues trying to push the envelope and so before I proceed I will be getting a couple more head shims to lower the compression since I really have come to love this engine and I don't want to hurt it . Funny I would have thought the bigger prop would give me detonation since the engine would be turning low rpms and high torque upping the cylinder pressure but the opposite came true.
I did try some SIG FAI fuel on the 9X6 and with an OS A3 plug it gave me the same 16,500. I really liked the way it ran on it too.
Since I performed the high rpm test I have been informed that this engine is engineered to make low rpm power (Oh Yea I noticed!!
) So small props are no longer going to be tested . That is cool, I love an engine that throbs out tons of torque and moves my plane around like a dragster. If I want the speed all I need is to dial in a lot of pitch, this bad boy will handle it.