[Allan Stern]

I have just started to fly my 8A and noticed that the underside was getting a very nice coating of exhaust on it. I was wondering if this was normal on most 8's? The second question is are there exhaust turndowns or extensions that might be added to redirect the exhaust from the belly? I also noticed that when I have powerd down it appears that I am getting what sounds to be a "back" fire under my feet. Is this the drumming or engine pulses 8's feel when fly? At high power I do not notice it only when I have throttled back on landing.

Thanks
Allan Stern

 

[John Ciolino]

I had the same issue plus I found some significant cracks at each end of the stiffener midway across the cooling ramp.

I patched the cracks and added downturns and it seems both problems are now solved.

I bought the downturns from a local builder but he got them from Vetterman. If they cost me any airspeed I can't tell it. And the belly is clean!

p.s. Use WD-40 to clean the exhaust residue, it works great.
John Ciolino
RV-8
N894Y

 

[Guy Prevost]

If you have a Vetterman exhaust, Larry really recommends his downturned tips for the 8A. My exhaust certainly works better with these tips. If you call him, I bet he will send you a set gratis.

The cackling when you pull the power is a common trait of RVs with Vetterman exhaust. If you pull the throttle more slowly it will happen less.

Regards,
Guy

 

[David-aviator]

This is for those who are coming down the exhaust road - my 4 pipes have not been trimmed and they absolutely leave no material on the fuselage bottom. I had a lot of stuff left over from the Subby adventure and after cleaning it off with scrubbing bubbles, the skin has remained clean.

I was going to trim the exhaust stacks a bit but have decide not to because cleaning the fuselage bottom is a royal pain in the back. The pipes may cost me a half knot in speed as they are but that's no big deal. The airplane goes plenty fast as is.

 

[Laser]

Just a thought

At the lower power setting, the sound might be an indication of a mixture that is too rich. Don't be afraid to lean a bit during approach or low power settings. Excess fuel will make the motor sound sluggish. Most of us tend to fly too rich during the landing phase. Just athought.