ORIGINAL: lsnover
Hi Guys:
Been fighthing my DA50 in my Aerotech Yak all summer. Been very tentative on the needles, as I'm somewhat new to gas, and have been told SMALL adjustments. My problem is my engine would run fine on the ground in every attitude, but in the air, as soon as I got in an extended upline or inverted, or any extended snap maneauvers, the engine would loose power and threaten to cut.
I tried the "balsa box" solution from the Carb vent. No change. I finally turned the Low needle about a 1/8 turn richer, and now it seems to be doing much better. It will still start to loose RPM in a long upline if I'm below half throttle, but I can fly inverted and knife edge almost indefinately. I'm at the point where its starting to not transition as quickly to the high end. I'd like to resolve the power loss on the uplines and in snaps. How far can I push the low needle before I have other problems?
Also, this engine vibrates pretty badly. On my glow engines, I always mount my props in line with the cylinder at full compression, and this seemed to help with vibrations. I wanted to do this with the DA, but others have told me to mount it horizontal on compression to keep the prop. from stopping in a bad position on a dead stick. It would seem to me to be better to reduce vibrations MOST of the time, then to worry about the dead stick that MIGHT happen. Will aligning the prop and cylinder make much difference with vibrations on these engines?
Thanks!
Lee
Lee,
if a gas engine looses power on the uplines then the high end needle is too lean. Go back to the factory settings and try this:
From the factory setting leave the high speed needle alone, lean the low end needle until the engine will no longer transition, then richen it back up about 1/8th turn. Now check your rpm at full power. LEan the engine until you get max rpm, then richen back up until you lose about 200 rpm
Now go fly.
Also vibration can be caused by a bad engine setup or an out of balance prop. It's very important to blance the blades and the hub. The DOD web site has some great videos on how to do this.
http://www.downonthedeck.com/videos_instruction.htm
Clikcon the video for prop balancing
Aslo what prop are you using, Too much prop can cause an engine to overheat and run lean