Prop mounting rotation vs. exhaust soot

[Brian Jackson]

Greetings.

Hadn't considered this before, but does anyone coordinate their prop installation such that blades are timed for minimal carbon deposit from exhaust? It occurred to me that my exhaust pipe is only a few inches ahead of a white prop, but the prop could be installed rotated such that it misses the firing pulses by 90 degrees. Is this something pilots do? Or is there a more important criteria for prop mounting? Trying to avoid soot. Thanks.

Brian

 

[WaspAir]

Might make a difference in the character of the noise as well, I imagine.

 

[JEFF TIPTON]

I would think that if you are using a reduction unit, the blades would be passing the exhaust more than you might imagine. The propeller and the engine rotation not being one to one.

 

[meglin]

White blades are not the best choice in this case. You will have to clean them after each flight. I usually only offer the white paddle option for pull motors. In this case we make them two-color, black on the back.

 

[Brian Jackson]

I would think that if you are using a reduction unit, the blades would be passing the exhaust more than you might imagine. The propeller and the engine rotation not being one to one.

Ahhh... I did not consider that, which negates the whole point. Rookie mistake.

i aRe eNgineEr

 

[Doug Riley]

Brian, you're not an engineer 'til you get your striped engineer's cap. Woo woo!

Seriously, I haven't watched my exhaust with rapt attention. Too far to turn my head. But I suspect that the typical 2-stroke expansion-chamber mufflers smooth out the "puff puff" quality, resulting in a more or less steady stream. Two-strokes run rich on purpose so, you're right, you'll get oily soot on your prop.

Wipe it off or leave as a badge of honor.