Dave,

Couple of questions. I'm running my 160DZ with a Performance Specialties muffler, an APC 15.5x12 4-bladed prop, and CP 30% Heli fuel. Its got about 2 1/2 gals of fuel through it (acutally mostly Powermaster YS20/20 as I've just switched over to the CP 30% Heli).


1. The engine is making all the power I could want, transitions great, and will idle all day long at 2,000. However, I'm only turning 7,550 RPM at top end which seems lower than ideal. The HS Needle is just a click or two back from peak. Should I be getting more RPM with this prop/fuel combo and, if so, is there a second peak I should be looking for or could something else be causing it?

2. When I switched over to CP 30% Heli, I noticed an immediate change in the characteristics of the exhaust residue on the plane. Instead of it being the mostly clear/oily residue that I saw with the Powermaster 20/20, it now has a darkish silvery-grey residue (almost aluminum looking). Is this characteristic of the CP 30% or do I have something bad going on?

Thanks in advance,

Tony

With the size prop you are running, 7550 is pretty good. The fuel residue would worry me though. Go back to the 20/20 and see if it changes back, or if you have the same type residue.

Let me know.