Forum: Military Aircraft of the Cold War

The F-15E was structurally strengthened to be a 9G airframe at the increased basic weight of 62,000lbs. So adding 2,000 lbs of missiles and even another 4,000 lbs of external fuel (600gal centerline tank) is only increasing weight by 10%, and only dropping G available to 8.2. Now the extra weight is still going to hurt the lift-limited side of the turn, but the Super Tomcat was far from super in turning, a 6.5G airframe at a weight of 50,000lbs. Now since the F-14D weighs 44,000 lbs bone dry, you can do the math as to what happens when it is loaded up. Going to full fuel (total weight 60,000 lbs), adding the externals they always have (2*270 gal brings weight up to 63,500 lbs), and adding the same weapon load (weight now 65,500 lbs) lowers the F-14D G limit to 5G. So now you are comparing a 5G plane with a fuel fraction of 30% using the same (slightly lower rated) engines as a 8.2G plane with a fuel fraction of 43%.
And on terms of drag, the F-14 has a HUGE parasite drag coefficient, just reduced wave and induced drag for the low and high end.

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Okay just ran all my numbers. Given an F-15E and an F-14D wo/AMRAAM capability (as it was when they were retired) I propose the following scenario. A long range heavy strike aircraft refuels, flies 300nm to the front line, penetrates that line by 200nm, drops a payload of 4 GPS guided one-ton bombs, and is engaged by an enemy fighter at 25K feet.

Loadout:
F-14D - 2 x AIM-9M, 2 x AIM-7M
F-15E - 2 x AIM-9M, 2 x AIM-120B

Cruise Speed (speed at which max range achieved and fight starts)
F-14D - 0.65M
F-15E - 0.80M

Fight Fuel (before having a range of only 500nm to return to tanker)
F-14D - 6880 lbs (used two 270 gal tanks during ingress)
F-15E - 12750 lbs (no external tanks used)

Cruise Speed Turn Rates in deg/sec (ITR/STR) and Acceleration in knts/sec (AB/Mil)
F-14D beginning of fight - (10/7) (5.5/2.5)
@ Bingo Fuel - (11/8 ) (6/3)
F-15E beginning of fight - (12/7) (6.5/3)
@ Bingo Fuel - (15.5/9) (9/4.5)

Best Turn rates in deg/sec@Mach (ITR/STR)
F-14D beginning of fight - (12.5@.8M / 9@1.15M)
@ Bingo Fuel - (14@.8M / 10@1.15M)
F-15E beginning of fight - (15.5@1.05M / 8@1.4M)
@ Bingo Fuel - (18@.9M / 11@1.45M)

Average AB Acceleration to "High Mach"
F-14D average 5.5 knts/sec to 1.7M
F-15E average 5.5 knts/sec to 1.65M

So under a realistic scenario the F-15E has better Instant and Sustained turn performance, better subsonic acceleration (to reclaim speed lost in turning), and more fuel to fight with. In calculating fuel used to get to the target and in calculating supersonic acceleration I took into account the lower drag carriage of the F-14Ds bombs and the much lower wave drag effects of the sweeping wing. The only thing not taken into account is the "trim drag" during cruise and G, both of which will hinder the F-14 more as it is the more stable design, especially with wings swept.

Forum: Military Aircraft of the Cold War

A Comparison F-14 Versus F-15E In The Fighter Role