Another disappointing weekend down. I was hoping to get a flight in this weekend after we replaced our hoses with 3003 hard line. This is essentially the exact same configuration that we flew without issues in 2008, the only differences being that instead of a 3-way valve up front, the second nose cooler has been completely removed from the loop, and I have a fan on the firewall cooler that was not on there previously.
Before flying, I came up with a test that I hoped would show me what I could expect in flight without the stress of flying with high temperatures. Once we were ready to go, we taxied out to the run-up area and let the oil warm to 180F (which takes a fair amount of time, so I don’t really suspect that we have a spun bearing or sticking ring or the other things that could cause high oil temps). Once the nose NACA cooler was warm to the touch, we went to WOT and directed the output of a leaf blower against the NACA to simulate the take-off roll. Our oil temperatures have been climbing so quickly, really by the time we’re established on downwind, this seemed reasonable. We could feel the air blowing out the outlet duct, relatively cool, but the oil temps rose steadily (maybe 1 degree per second). When we would pull the leaf blower away from the cooler, it was cool to the touch. I think that this was telling me that I’m getting plenty of air to cool the oil, but not enough oil to the nose, still, to cool the engine oil sump off. I believe that’s telling me that the vernatherm is not seating at high temperature, and so the hot oil just goes back to the engine. Because of this I elected not to fly the airplane, but rather bring it back and open it up and check/replace the vernatherm.
Since we were down and didn’t have an extra vernatherm laying about, we fitted up some washers and bolts onto the nose wheel to try out the new towbar. This seems to be working really well when pulling the airplane, we may need to rotate the wheel backwards before putting on the tow for backing it up. We’re also installing a winch in the back of the hangar so that once we have this working we can just hook to the towbar and pull the airplane into the hangar.
Posted By: Brett FerrellSunday June 13th, 2010 at 9:53 PM