or 1 ----- fuel flow {p309} If maximum endurance is desired, the flight condition must provide a minimum of fuel flow. To understand the impact this has on endurance, we have to look at brake specific fuel consumption (BSFC). While the peak value of specific range would provide maximum range operation, long range cruise operation is generally recommended at some slightly higher airspeed. As a result, your airplane is carrying around a lot more power than is required for cruising. Aircraft are not designed solely for cruising; they must also takeoff and climb. Thrust Specific Fuel Consumption Is Lower Due To Lower Temperature Thrust Required (drag) Remains The Same At Best Endurance Airspeed Regardless Of Altitude Fuel Flow Is Lower At Higher Altitudes Up To The Tropopause So Specific Endurance Is Improved. If maximum specific range is desired, the flight condition must provide a maximum of speed per fuel flow. of fuel/hr. Figure. This is a measure of fuel efficiency within a shaft reciprocating engine. Specific Air Range & Specific Endurance Key cruise parameters are Range (distance flown) and Endurance (time of flight). Figure 11: Airspeeds for maximum endurance vs. maximum range. Cruise control of an aircraft implies that the aircraft is operated to maintain the recommended long-range cruise condition throughout the flight. The following formula determines the specific endurance for any given flight condition. As stated earlier, every effort is made to maintain the SG of … Range must be clearly distinguished from the item of endurance. It simply the rate of fuel consumption divided by the power produced and can also be considered a as power-specific fuel consumption. Specific Endurance = Flight Hours per Hour / Pounds of Fuel per Hour. Specific Endurance = flight hours/pounds of fuel OR flight hours/hour / pounds of fuel/hour ... • Maximum Range = maximum of speed per fuel flow . Go to Top Final Thoughts . maximum specific range varies only about 1 % from the mean value, which is equivalent to less than a 2-knot change intheheadwind ortailwind component. Specific Range •Affected by: –Aircraft Gross Weight –Altitude –Aerodynamic configuration of the aircraft 17 . Specific examples of aircraft designed for these conditions include Burt Rutan s Voyager (maximum range), Unmanned Aerial Vehicles (maximum endurance), U-2 reconnaissance aircraft (maximum range and altitude), and the P-3 Orion submarine hunter (maximum endurance). 2 proportion to SMOE. Question: What Is The Effect Of Altitude On Specific Endurance For A Jet Aircraft? Cruise Control. A brief discussion on cruise flight performance of piston prop aircraft, including two examples of range and endurance calculations. 6. AP3456 - 2-1 - The Effect of Variation in Specific Gravity of Fuels on Range and Endurance . Range Vs Endurance 16 . 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