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Old 02-13-2013, 08:34 PM
  #844  
FlatSpin
 
Join Date: Jan 2007
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Default RE: New Evolution 10cc gas engine


ORIGINAL: josephcraig

Dave,

do you think the factory needle is the way it is for a reason...i'm in the process of of putting my plane together on hanger 9 katana 50..i've run my engine some on the test stand..can't really tell on the stand until the engine is off the load..i did take some 320 sandpaper and knock the edge off the high side needle on the end...i'm gonna run it the way it is for a while to see how it adjusts...what blades have you tested and which size you like the best far as performance ...12 x 6 in the manual says best all around...
I'm sure there is some reason the HS needle is flatter than standard glow needles, but I and others at my flying field have found that there isn't any fine tuning adjustment to it. One click makes a difference between lean and rich. Another guy took his needle out to examine it before firing it up and discovered a burr on it. He took a jewelers needle file and touched it up. I'm not recommending anyone modify their needle, but if you cannot get it dialed in after a lot of flying time, it may be something to consider. I had over 1/2 gallon through my engine before experimenting with the needle shape.

On the 8lb Meridian airframe (dry weight, no fuel), my Evo likes a 12x6 APC the best. I flew it with a 13x6 and it worked pretty good but you could tell there was a performance decrease in aerobatic "snappiness". I think 8lbs is about the "performance limit" for this engine. I've also put the Evo on a 7lb trainer with a 11x7, 11x7, 12x6, 13x4 and 13x6. On that plane, the 12x6 and the 13x4 was the best match. I have a good 60-75 degree vertical climb out with those props.

Dave