I’ve been ordering supplies like mad that I thought might help us with our oil temperature issues. I’ve got a 2-pass Positech 4218MN oil cooler coming. It has more tubes than the stock cooler, and being two pass should have nearly 1/3 more heat-rejection capacity than the stock cooler. I’m hoping we can mount it in the same location in the nose as the factory cooler and get the heat out of the oil and into the cabin in the winter time. While we wait for that, I got some smoke generators from Grainger to see if my cowling augmentors would pump air through the oil cooler when the cowling plugs were installed. We hadn’t been brave enough to fly with them yet, and I thought this might give us an idea what difference (if any) the they would make. I video recorded both runs so we could review the tape and see if there was any difference. The video was probably over zoomed, but it did seem that the run with the plugs in helped pull air into that NACA, and the run without seemed to have the engine sucking all of the air towards the colpilot side at times. This probably isn’t true at speed, but it seemed to indicate at least the cowling plugs wouldn’t hurt us any. I also mounted a 5″ high-capacity radiator fan from Jegs onto the discharge side of the rear oil cooler to help overcome the pressure drop across the fins (and help with ground running). Scott Swing also thought that the flox-and-micro lip we and on the discharge side of the nose cooler was really hurting our air flow, so we ground that out. Elizabeth flew again tonight and our temps just barely exceeded 230F, and would start falling right away when the power was pulled. That’s real progress, but still too high. Of interest, the blower in the back really pulled the heat out, and cooled the oil over 10 degrees just on the taxi back to the hangar, so I highly recommend that little gem. I may need to put it on a switch for winter, but right it comes on with the master.
Posted By: Brett FerrellSaturday June 5th, 2010 at 9:43 PM