Teaching the correct way to break-in an engine

[RTK]

You reminded me Joe. People tend to load there engines down with too much prop, adding additional heat. Every body likes to show off how big there piece of wood they are swinging

[JoeAirPort]

That's very true, we all want to run the biggest diameter prop we can. But the engine doesn't always like them. A good friend of mine that was ahead of me on the gasser curve warned me about running my DA 50 on a test stand. He said keep the RPM's down and very short runs to keep it from over heating (so I kept it under a minute). That was some good advice.

[Wheels]

Hey guys what about no cowl on initial flights of a brand new gasser, is that the best cooling possible because of som much air moving around? Or the worst thing yopu can do because there's nothing ducting air over the fins?

[RustyTumbles]

I have benn told just to fly new gas engines. Once you put them in the plane. Run it on the ground and tune it for a SLIGHTLY rich tune and so it transitions well. Then go and fly it. Having it in the plane (with cowling on) gets the right amount of air over the engine and will allow you to get a feel for the tuning of the engine. The intial flights of my ultimate (DA50) were very rich. I just tweeked the needle 1/8 of a turn and it was alittle on the rich side. I flew it like that for 10 litres (2/12 gallon) then leaned it a little more and I haven't touched it since. It now has almost 20 litres (5 Gallon) through it and I'm about to switch to synthetic oil very soon. It continues to get stronger every flight.

[RTK]

Yep, that's it.