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Range and Endurance Mass Brief Aim • To Learn the principles of range and endurance of an aircraft in flight, and the factors that effect these conditions Application • In long distance flying the maximum Range is important • When holding the maximum Endurance or time in the air is important Overview • Revision – Thrust and Power • Definitions • Principles – Range and Endurance • Considerations • Airmanship Revision • Thrust • Power IAS Thrust Power IAS Definitions • Range – Air distance travelled for a given fuel burn-off (distance) • Endurance – Time in flight for a given amount of fuel (time) • Best Range Speed – A certain speed that will allow the aircraft to fly the furthest distance. • Best Endurance Speed – A certain speed that will allow the aircraft to stay in the air for the longest time Principles • Maximum Range – Range is a certain distance, usually measured in nautical miles – Range is dependent on drag – Maximum range occurs when total drag is at a minimum Principles • Maximum Endurance – Is a certain amount of time an aircraft can spend in the air. – Endurance is dependant on the power setting of the aircraft – Power setting determines the burn-off (usually in Litres per hour) – Minimum power means minimal fuel flow – Maximum Endurance occurs at minimum power Considerations • Effect of Airspeed – Increased airspeed means a decreased Range and decreased Endurance – Decreased airspeed means a decreased Range and decreased Endurance Considerations • Effect of Weight – Increased weight, fly at a faster speed, however range will not change as you are always flying at best L/D ratio. – Increased weight, requires more power to fly level, so there will be a decrease in Endurance – Decreased weight, fly at a slower speed, however range will not change as you are always flying at the best L/D ratio – Decreased weight, requires less power to fly level, so there will be an increase in Endurance Considerations • Effect of Wind – A headwind will decrease the range, but have no effect on Endurance – A tailwind will increased Range, but have no effect on Endurance • Power – An increase in power will reduce both Range and Endurance – A decrease in power will reduce both range and endurance Considerations • Effect of Altitude – An increase in altitude will not change range as the L/D ratio is the same, however speed and power will need to be increased – An increase in altitude will decrease the endurance since a greater power setting is required – A decrease in altitude will not change range (Same L/D ratio) – A decrease in altitude will increase Endurance as a lower power setting is required – In reality range is affected by propeller efficiency which decreases with altitude, which would decrease the range. Airmanship • Set power according to cruise tables in POH • Lean the mixture in the cruise • Never exceed any of the aircraft’s maximum limitations (MTOW or VNE) |
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