My three hour round trip last weekend presented the perfect opportunity for me to check my fuel burn and verify my fuel gauge readings. At the airport today I leveled the KR and pumped the tanks dry into a calibrated fuel can. I started the trip with nearly full tanks, which I seldom do. I had right at 12.25 gallon in each of the 12.5 gallon wing tanks, I have no header tank. I carefully monitored switching tanks every 15 minutes to keep the tank levels nearly equal. My gauges today were reading 1/4 tank on each side with the needle touching the full side of the 1/4 tank line. I pumped 4.1 gallon from each tank to empty. https://dl.dropboxusercontent.com/u/32133949/IMG_8717.JPG for picture of gauges then zoom in.
The math: 24.5 gallon minus 8.2 gallon = 16.3 gallon burn = 5.43 gallon per hour at 2450 to 2500 rpm cruise (mixture leaned at cruise) which included engine warm up, taxi, takeoff, climb, and decent ( 22.4 mpg). That's better than my Toyota truck but not as good as my Buick by 7 mpg. But then the round trip in the Buick would have been 7 hours non stop. My rule of thumb is never less than 1 hour fuel remaining without a planned fuel stop. I confirmed that I should have 1.5 hours to empty left in the tanks at 1/4 tank read. As the three hours was measured on an hour meter (clock time) I averaged 121.6 mph which included engine start, warm up, taxi, etc.. Winds at altitude were not a significant factor on the trip. I was also pleased to see the oil was at the same level as the start of the trip. Not bad for an engine with 2300+ hours since factory overhaul. The trip one way included a climb to 5500 feet and to 8500 on the return. All in all I'm pleased. Larry Flesner
