tukkus,

Interesting question and interesting replys. Seems to me that an engine with that big fan in front of it is going to run at the same temp whether it's on a stand or an airplane, unless it's in cowl situation where it runs hotter on the plane.

I've been playing with this stuff for about a year and have only assembled three ARFs with new engines. I like to run the engines on the bench before I go to the field, but I mount them in the airplane and then tie the plane down to my picnic table. This way I can do the "break-in" and fiddle with the needles without a gaggle of experts standing around giving advice. That way I learn to tune and I do my range checks at the same time. Scr*w the neighbors. Less noisy than a lawn mower.

If I decide to take my next new engine directly to the flying field, I think the 35 years of combined experience of ronwc and qow589 outweighs the "bench run a new engine" opinion, and I won't lose any sleep about harming the engine.

rcjon