jetcareers - View Single Post - Maximum Endurance and How Does A Tach Work?

aerospacepilot · September 30th, 2007, 16:46

Hey,
I am flying in a flying club that charges their aircraft on tach time. I think it is a great idea, afterall, maintenance and fuel burn is directly proportional to tach time. Also, I find I fly much safer when I am being charged on tach time. But I am curious how I can minimize being charged.

How does the tachometer work? Is tach time directly related to RPM's? How is 1 hour of tach time calculated (for say a C-172)?

What speed should I fly at to minimize tach hours and maximize flight hours. My first thought was best L/D, but then I realized that endurance is proportional to Cl^1.5/Cd. How would tach time be related to endurance? Same question with what altitude should I fly at. I know endurance is proportional to density^.5, so max endurance comes from flight at sea level, but is the same true to minimize tach hours?

I am just looking for things I can do to minimize my costs. I know the general concensus would be to pull the power back, but I am interested in specific airspeeds, RPM's, and altitudes (for a C-172) that would minimize tach hours?
Thanks.

September 30th, 2007, 16:46	#1
aerospacepilot Junior Member Join Date: May 2007 Location: SF Bay Area, CA or Boulder, CO Posts: 174	Maximum Endurance and How Does A Tach Work? Hey, I am flying in a flying club that charges their aircraft on tach time. I think it is a great idea, afterall, maintenance and fuel burn is directly proportional to tach time. Also, I find I fly much safer when I am being charged on tach time. But I am curious how I can minimize being charged. How does the tachometer work? Is tach time directly related to RPM's? How is 1 hour of tach time calculated (for say a C-172)? What speed should I fly at to minimize tach hours and maximize flight hours. My first thought was best L/D, but then I realized that endurance is proportional to Cl^1.5/Cd. How would tach time be related to endurance? Same question with what altitude should I fly at. I know endurance is proportional to density^.5, so max endurance comes from flight at sea level, but is the same true to minimize tach hours? I am just looking for things I can do to minimize my costs. I know the general concensus would be to pull the power back, but I am interested in specific airspeeds, RPM's, and altitudes (for a C-172) that would minimize tach hours? Thanks. __________________ http://www.youtube.com/watch?v=oX6pNsQzRy4 Props are 4 boats. Jets are 4 hot tubs. Rockets are for aerospacepilot!