2018/3/11 Calculation of Form Factors 园上清大华 Fuselage Drag Breakdown 国上清大学 Wing,Tail,Strut,and Pylon F-+0(自+m目】儿网 2.30 Fuselage and Smooth Canopy: m-(+9+ 123) Nacelle and Smooth External Store: FF-1+(0.35/n 02.32 where 了-导mA (12.33) 0 .Base drag D=DANC+DINC DC DIcD.rC DiTe oorornenin ong oorn enin Song 32 Fuselage Drag=Friction Drag Base Drag 圆上清大坐 Fuselage Drag General Equation 圈上活大整 D=DINC DIc+Di+Dp.BuSE With span denoted by b and the aspect ratio A=b2/S we have D Dp.BASE 学-业会a份)xd8)]F- 0.029 Hoerner suggests Co,auSE= Then the fuselage drag coefficient is given by Then the fuselage drag coefficient becomes 0.029 s Co-K cyF+ 0.029 10F s是20器，aw 33 34 Fuselage Form Factor:different correlations 图上洋大峰 Wing Form Factor 圆上清大学 (Kw=1+) k-factor in fuselage drag correlation k-factor in wing drag correction K=1+k) 01 0.8 nkinson 0.6 0.5 0.4 8 0.2 Qatcom 0.1 0 ★★三 10 15 20 0 0.05 0.1 0.15 0.2 Fineness Ratio Ud Thickness Ratio tc 35 36 62018/3/11 6 © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Calculation of Form Factors © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Fuselage Drag Breakdown •32 LN LF LC LR DF D D D D D D D       p NC f NC p C f C p TC f TC , , , , , , 0 Base drag © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Fuselage Drag= Friction Drag + Base Drag •33   , , , , . Re, f NC f C f TC p BASE wetted p BASE D f D D D D D D S D c c M qS S qS        , 0.029 D BASE wetted f base c S c S Hoerner suggests  3 0.029 2 wetted base D f wetted f S S c c S S S c S         Then the fuselage drag coefficient becomes Hoerner, S.F.: Fluid Dynamic Drag, published by the author, 1958 © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Fuselage Drag General Equation •34 2 2 2 2 2 2 4 4 4 wetted base S A d L d k dL k A k A F KF S b b d b S k d A k A d K S b b                                                     With span denoted by b and the aspect ratio A=b2 /S we have 0.029 4 D f f c K c F c F         Then the fuselage drag coefficient is given by 0 5 10 F cD © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Fuselage Form Factor: different correlations •35 kfactor in fuselage drag correlation 0 0.2 0.4 0.6 0.8 1 0 5 10 15 20 Fineness Ratio L/d k NAA Datcom Torenbeek Hoerner(Kf=1+k) © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Wing Form Factor •36 k - factor in wing drag correction 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 0.05 0.1 0.15 0.2 Thickness Ratio t/c k Jenkinson Torenbeek NAA Hoerner DATCOM 2 DATCOM 1 (Kw=1+k)