Thursday, August 4, 2011

Nearmiss.

I've been flying at the field every day this week since I mowed a path through the high grass and modified the fence a bit. I found a fuel shut off in the fuel line, they can't fool the old guy. Today I wanted to look at the head on the mower as it makes a noise when it starts up and I figured it may be filled with carbon. Overhead valve engine. I set up and got in a flight. At lap 2 I noticed something didn't look right. As lap 3 passed over the fence it struck me that I didn't remove the 2 sections needed for clearance. I backed off and finished the flight.
One of my LA .40's has been giving me trouble. I set the rpm and the engine will speed up and run away. Nothing worked to cure it. I drilled an extra hole in the spray bar, added lots of nitro, changed heads, changed props, same results. I had thought this engine was the one with the worn cylinder liner. I have to use the starter to get that one going after a flight the compression is so low. That is the only thing I haven't tried, lowering the compression a lot. I took the ball end mills and put the biggest one in the wood lathe, set it at lowest speed and pressed the head against the turning cutter. I took some off the combustion chamber but not a real lot. I went outside and ran it with very good results. I will mow the field tomorrow and will try the engine in flight after. After that I plan to go to Oneco and mow that circle. A couple more flights there will let the night worker know I'm still around.

1 comment:

robotfan said...

Cure for the runaway OS-40: Use a venturi from an OS-20 (Tower part number OSMG9252), and a lower pitch prop, as per Aeromaniacs article at

http://www.aeromaniacs.com/latocl.htm

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