F-15 in the interceptor role, hitting limits

Cold war, Korea, Vietnam, and Desert Storm - up to and including for example the A-10, F-15, Mirage 200, MiG-29, and F-18.
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by sprstdlyscottsmn » 09 Jun 2015, 22:24

Knowing that misuse of effect affects how effectively the message is received is all well and good, but unfortunately I am just a bad typist. I hit keys fast and I don't proofread well. My apologies John. I will strive to be more diligent.
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by geforcerfx » 09 Jun 2015, 23:20

Were these numbers with 600 gallon tanks? I saw clean listed so assumed not. Everytime I saw the 120th fw when they had eagles they always had 600gallon tanks, I also see that a lot on videos of scrambles.


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by sprstdlyscottsmn » 09 Jun 2015, 23:28

No, in all these figures there were no tanks used. I was trying to see the difference in fastest intercept profiles. Taking off with tanks and dropping them when empty would have been fun, but you would end up so far away from base that you may or may not even be able to get up to max speed once empty before you went Bingo. There are seemingly ENDLESS performance profiles I would love to calculate.
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by sprstdlyscottsmn » 26 Aug 2015, 18:06

So it was bugging me that I never went back to update the intercept profile for the F-15C after it was pointed out that the body stations are BAL limited. For the "standard" load of 6 AIM-120 and 2 AIM-9 the top intercept speed is now drag limited to Mach 2.0 (based on interpolation of two different speed charts)

Max Time for the Intercept is now just under 14 minutes and range has dropped to 143nm. It still has more range and I higher speed than an F-16C or an F/A-18E in a pure intercept profile.

Sorry for bringing up a dead thread but I had to get this out of my head.

P.S. for the same reason I also did an iterative F-35 intercept. This is a "Cold War" thread so I won't go into it here, maybe if the need presents in another relevant thread I will.
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by sferrin » 26 Aug 2015, 18:44

"BAL"? Re the Mach 1.4 limit, that seemed odded to me as well as I'd read of F-4s doing AIM-7 launches well above that back in the day. (Of course they're semi-submerged on the F-4 which would have had an effect.)


Att: John Will (or anybody who might know)

are you aware of any top end differences between the -229 and the -129 on the F-16? I'd think with the large differences in airflow / exhaust velocity that that would translate into different behavior at higher speeds.
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by sprstdlyscottsmn » 26 Aug 2015, 18:53

sferrin wrote:"BAL"? Re the Mach 1.4 limit, that seemed odded to me as well as I'd read of F-4s doing AIM-7 launches well above that back in the day. (Of course they're semi-submerged on the F-4 which would have had an effect.)

Basic Aircraft Limits, or in this case 2.5M. I am basing my calculations on an F-15E manual which has performance data for clean and 4xAIM-7 without CFT and with the -220 motors. I interpolated the drag data with another loadout of 4xAIM-7 and 4xAIM-9 with CFTs to get the needed performance. The F-15E is placard limited to 1.4M with anything body mounted, but someone was able to show me the page from the F-15A chart showing BAL.
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by johnwill » 27 Aug 2015, 00:31

sferrin wrote:"BAL"? Re the Mach 1.4 limit, that seemed odded to me as well as I'd read of F-4s doing AIM-7 launches well above that back in the day. (Of course they're semi-submerged on the F-4 which would have had an effect.)


Att: John Will (or anybody who might know)

are you aware of any top end differences between the -229 and the -129 on the F-16? I'd think with the large differences in airflow / exhaust velocity that that would translate into different behavior at higher speeds.



I don't know of any differences, but my F-16 insider knowledge terminated in 1986. Although there are probably performance differences, as a guess, I'd say the handbook limits are the same, as there is little if any use for top end performance. To extend the speed limit would require a full set of analysis and possibly flight test for Stability & Control, Propulsion, Performance, Flutter, Loads, Thermo, etc.


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