Delete comment from: Elements Of Power
Guys,
I used the HAF F-16 manual and this article:
http://defense-update.com/products/c/F-16-CFT.htm
for the drag estimation of centerline fuel tank. Drag of a 370 gal centerline tank w/no adjacent stores:DI=27. Pylon DI= 7. (12% of total ~4) A 300 gal drop tank on centerline DI =15 (12% of that total would be ~2) both very low. The real drag adder is the external non-wingtip AMRAAMs and launchers (x2) =20. I estimated a DI uppers on the Block 60 to be the same as the Block 50, which would be DI upper = 22 or 24 depending upon tank used as basis. The article mentions specifically the CFT set as "12%" of 300 gallon tank, but that is a general statement that may be the average drag reduction for the 300 in the subsonic region. I'm using 4 as the estimated DI for the CFTs for the transonic region, but even if it is 2, The difference between DI totals of 22 and 24 won't be seen in any guesstimate we can do. And in any case I doubt it will make as much difference as accounting for all the weights involved. I see weight as more important (back to lift and wave drag dominance). Example: the empty weight of the CFTs (900 lbs) being more than the pylon/empty 300 lb tank weight of 569 lbs).
Mar 2, 2015, 6:08:10 AM
Posted to The F-35 and the Infamous Transonic Acceleration ‘Spec’ Change: