RE: DA 50 midrange setup
Here's what I do for any DA50 I get my hands on. I have hundreds of flights on them and the one Dave had looked at he said was wearing perfectly and running very clean.
Despite what people expect, DA50s don't run that great out of the box.. the midrange is not all that good and the idle is rocky. Dead sticks at low throttle are not uncommon if the needles are even just slightly rich (which is where everyone thinks they need to set them to run a new engine for break in) ... here's what I do to minimize the pain:
Misconception #1 - low end needs to be rich to prevent overheating. Not true, you want to lean the low end as much as possible the only challenge here will be keeping the engine running or from dead sticking.
Misconception #2 - DA's take a long time to break in.. NOT 2 gallons is more than enough.
Here's a tried and true recipe for getting the most out of your DA50>
1> Run BelRay S2 or Lawnboy Petroleum 2-Stroke oil 32:1 Regular Unleaded (don't use premium)
2> Use a 22x8 MenzS or NX wood prop (you don't want a large load on a new engine)
3> Set the high needle for highest RPM, then back off 300 RPM (you can do this by ear, 300 RPM is pretty noticeable)
4> Set the low needle so the engine just barely stumbles from idle to WOT during a rapid transition, once this point is attained, richen the low needle by the width of one screwdriver blade at a time until the hesitation stops
5> Check WOT again, tune for max RPM, then back off by 300
If you get this right, the midrange won't be too bad, and you won't have the "die at idle" or "die at touchdown" problems most people run into with these engines DA's are extremely sensitive to needle settings.
You may have to deal with a little higher idle at first until you get a gallon or two through it, after the first gallon its OK to start lowering the idle, by the second gallon, you should be able to final tune the engine and not have to touch it again.
During this period also just FLY the airplane. Avoid prolonged WOT use, and especially hovers and high stall events that will allow heat to build up in the cowl. The first 15 minutes of an engine's life is the most critical!! Keep it cool!
After TWO gallons, it is quite safe to switch over to BelRay H1R full synthetic, run that at 50:1 Running break in oil more than 2 gallons in these engines is a waste and just lays down heavy carbon deposits where you don't want them. My original DA50 has 500 flights on it and is still running like new. I have never touched the needles since my final tune after 2 gallons. Best running engine I have ever owned (well, OK, I like my 3W QQ106 too...)
DP