BODY RESISTANCE 



Example (il). Resistance of Wheels. Consider two 800 

 by 150 wheels. Without fairing 

 r= 2 x -000184 x 800 x 150 = 44/2 pounds at 100 miles per hour. 



With shields to the rims only 

 r 2 x -000113 x 800 x 150 = 27-1 pounds at 100 miles per hour. 



While with the complete shields from tyre to tyre 

 r 2 x -000062 x 800 x i 50= 14-9 pounds at 100 miles per hour. 



Example (12). Resistance of a Cockpit. Suppose the cock- 

 pit is 2 feet wide and 3 feet long at the opening, then the resist- 

 ance is given by 



r = -7 x 24 = 1 6 '8 pounds at 100 miles per hour. 



Example (13) Resistance of a Windscreen. Take a wind- 

 screen 8 inches by 1 2 inches, then the resistance is given by 

 r = 29 x = 19-3 pounds at 100 miles per hour. 



Example (14). Resistance of Engine Cylinders. Take the 

 case of a 9-cylinder stationary radial engine with the cylinders, 

 which are six inches diameter over the gills, projecting 4 inches 

 beyond the cowling, then the total area of cylinder can be taken 

 as = 9x^x^=1 -5 square feet. 



.'. r = 31 x i'5 = 46-5 pounds at 100 miles per hour. 



Example (15). Line of Action of Body Resistance. Let us 

 assume the following particulars : Take the top fuselage longeron 

 as datum ; reckon a's in inches and positive for parts above the 

 longeron ; use the batches defined on page 83 ; let the values 

 of a's and R's be as in the table : 



Therefore the line of action of the body resistance is at a 

 height above the top longeron of 



' l848 - - .97 inches, 

 190 



i.e. it is 97 inches below the top longeron. 



