Slide 26 of 58
   Notes:  
 
Substantiating Data for Drag Reduction
Minimum drag data for two configurations employing vertical tails shows that the vertical tail accounts for 5% to 10% of the total airplane minimum drag at a cruise Mach number of 0.9.  Configuration features like area distribution and interference effects results in variation of the tail contribution.  Nevertheless, 5% CDmin is still significant.