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1、3 Sizing from a Conceptual Sketch,IntroductionTakeoff Weight BuildupEmpty Weight EstimationFuel Fraction EstimationMission ProfileMission Segment Weight FractionSpecific Fuel ConsumptionL/D EstimationFuel Fraction EstimationTakeoff Weight CalculationDesign Example:an anti-submarine warfare aircraft,
2、Introduction,Use of Historical DataEvaluation to a Number of Proposals to Meet the Design RequirementsInevitable Difference Between Prediction and actual flightA Simplified Sizing Method for Quick Estimation of Takeoff Weight,Takeoff Weight Buildup,Design takeoff gross weight and Maximum takeoff wei
3、ghtClassification of Weight,Weight Equation,Known,given by design requirements,Unknowns,dependent on W0,Takeoff Weight Buildup,An alternative form is,and then,if,Impractical design,practical design but unreasonable,practical design,improvable,practical design,reasonable,Takeoff Weight Buildup,Lets g
4、o back to estimation of W0,Calculate iterativelyNo sudden weight changeCannot be used for fixed-engine sizing,Empty Weight Estimation,Empty Weight Estimation,For composite material,that of metal,that of metal,ACM,FBE,Fuel Fraction Estimation,for mission,required by design specifications,cannot be us
5、ed,mission,aerodynamics,fuel consumption,depends on,The fuel used is a function of the aircraft weight.The reason is that the aircraft weight during mission affects the drag.,Fuel Fraction EstimationMission Profile,Fuel Fraction EstimationMission Segment Weight Fractions,A simple cruise mission prof
6、ile,MSWF,Fuel Fraction EstimationMission Segment Weight Fractions,Fuel Fraction EstimationMission Segment Weight Fractions,燃油重量系数估算单位耗油率,定义：单位耗油率（“SFC”或简写为“C”）是燃油消耗率除以由此产生的推力。喷气发动机，单位耗油率通常用每小时每磅推力所消耗的燃油磅数度量。螺旋桨发动机的SFC通常用 表示，它是指每小时每螺旋桨轴马力功率所消耗的燃油磅数（或一个“制动马力”：,ft-英尺,lb-磅).,燃油重量系数估算单位耗油率,燃油重量系数估算单位耗油率,
7、燃油重量系数估算单位耗油率,燃油重量系数估算L/D估算,22-3/2013,燃油重量系数估计L/D估算,燃油重量系数的估算L/D的估算,燃油重量系数的估算L/D的估算,燃油重量系数的估算L/D的估算,燃油重量系数的估算L/D的估算,燃油重量系数估算,起飞重量计算,设计目标,确定参数,选择展弦比,草图,发动机的SFC,设计实例：反潜机（ASW）,设计实例：反潜机方案草图,设计实例：反潜机详细方案草图,设计实例：反潜机L/D估算,设计实例：反潜机起飞重量的确定,设计实例：反潜机权衡处理,设计实例：反潜机权衡处理,设计实例：反潜机权衡处理,图3.11 航程权衡分析图,设计实例：反潜机权衡处理,设计实例：反潜机权衡处理,设计实例：反潜机权衡处理,ENDTHANK YOU,
