Accepted practice is a flow rate one point five times the maximum engine requirement in the worst possible flight configuration, generally nose high climb. You can't have too much fuel flow capacity unless you are over powering your carb.
Another rule of thumb that works well on our type of engine is that fuel burn will be 1/2 pound of fuel per horsepower per hour. My 0-200 for example at 65 percent power = 65/2 =32.5 pounds / 6 ppg = 5.41 gph, very close to actual. Just remember, silence in flight is for sail planes............... Larry Flesner --------------------------- Larry's fuel burn rate is correct. Of course when calculating minimum fuel flow, one wants to use 100% power setting at your worst fuel flow rate. As Larry says, that's usually steep climb and while you are low on fuel. The 1.50 times delivery for maximum fuel flow is for gravity feed systems. A pressurized fuel system requires only 1.25 times of maximum fuel flow for the engine. So, my gravity fed O-200 requires a minimum flow rate of 100% x .5 lb/hp/hr / 6 ppg x 1.5 = 12.5 gph minimum flow through the carburetor. Larry's O-200 with fuel pumps supplying the carb only requires a maximum fuel flow test of 10.42 gph. -Jeff Scott Los Alamos, NM ---------------------------- From the FAA handbook and fuel flow testing... For gravity-flow fuel systems, the fuel flow rate must be 150 percent of the takeoff fuel consumption of the engine. For fuel pump systems, the fuel flow rate for each pump system (main and reserve supply) for each reciprocating engine must be 125 percent of the fuel flow required by the engine at the maximum takeoff power. However, the fuel pressure, with main and emergency pumps operating simultaneously, must not exceed the fuel inlet pressure limits of the engine. _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
