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Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 15:14
by hummingbird
magnum4469 wrote:Years ago flying the "A" blk 15 against F-14D doing BFM and ACM sorties. We were flying with centerline and 2 bag jets, the F-14s were clean. In fights with the 2 bag jets it was about an even match with slight advantage to F-14s. Centerline jets had huge advantage vs F-14. Clean vs clean jets the F-14 would be no match for the F-16. You can't just compare the turn rate you also have to look at the radius. The setups were all standard, 20k, 350kts, line abreast 1.5nm split, check away 30 degrees, at approx 2nm separation turn in and fights on. Meet 180 degrees out, the F-14 would go into horizontal break two circle turn, Vipers would pull vertical and roll and pull to 6 oclock. Employing either AIM-9 or gun. The F-14 provided a huge target compared to Viper for putting the pipper on. The tail stab of the F-14 (33' wide, compared to 32' wide of the F-16 wing) had almost the same area as the entire wing of the Viper. As soon as you saw the wings sweeping forward you knew he was out of energy and went in for the gun shot. Not to take anything away from the F-14, it was a great platform for what it was designed for, keeping Bear bombers away from carrier air group and shooting down cruise missiles but as far as a knife fighting dog fighter it came up short, even with the "D" model upgrades.


Hi Magnum,

Don't worry we are also taking the radius into account since this is where the F-14 has the real advantage versus the Viper, whilst at the same time the Viper enjoys a higher max sustained rate. Thus in a pure horizontal contest it would end up a rate vs radius fight.

Also I notice you pointed out that the std. tactic for the Viper was to go vertical straight away after the merge, which incidentally mirrors exactly what F-15 pilots would do, whilst they ofcourse did this out of nessecity as they knew they would never win a straight out turn contest with the Cat. Doing it anyway would end the fight very quickly in the Cat's favor. By comparison the Viper is on more equal grounds, but again I suspect they went vertical for a reason.

Btw, were these top gun students you were flying with?

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 15:43
by eloise
hummingbird wrote:I didn't really make any estimations, and I certainly nowhere went contrary to charted info (!)
What I did do was provide the actual charted lift curve for the F-14, and from it can be observed that no real change occurs until Mach 0.85, which is where the high lift devices stop operating.
Thus I could/can correctly state that the F-14 will be able to pull the 9 G's instantanuous at lower alts before the F-16, as the lift curve straight away lets us know this. Thus whilst I can't provide the exact G @ specific speed past 7.5 Gs I can instead positively state it would hit 9 G long before M 0.85 at for example 10 kft.

I think because the charted lift is at 35k ft, the wing swept is delayed compared to low altitude
Image
and F-14 has lower G limit than F-16.
hummingbird wrote:Because that's how the discussion garrya linked you guys started originally, as a comparison in performance between the "current" F-14, F-15 & F-16 in order to illustrate the typical expected performance of the aircraft as seen on duty. How you got that twisted into a "best version vs best version irrespective of time frame" debate I don't know

Current F-14 has retired

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 15:55
by garrya
eloise wrote:I think because the charted lift is at 35k ft, the wing swept is delayed compared to low altitude
and F-14 has lower G limit than F-16

That indeed true but iam wondering, does F-14 wing has only 2 mode of operation such as below 14k ft and higher than 20k ft or the two line is only for reference and the sweep will varied with altitude?
For example: if the altitude is 50k ft, will the wing fold back later than at 21k ft? Or does the automatic system treat all altitude higher than 20k ft the same.
P/s: nevermind, i found the answer:
Image

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 16:15
by sprstdlyscottsmn
garrya wrote: if the altitude is 50k ft, will the wing fold back later than at 21k ft? Or does the automatic system treat all altitude higher than 20k ft the same.

Everything below 14k is the same and everything above 20k is the same.

hummingbird wrote: What I did do was provide the actual charted lift curve for the F-14, and from it can be observed that no real change occurs until Mach 0.85, which is where the high lift devices stop operating.

Except I ran the math and showed that the CLmax is indeed changing the entire time. The simplest evidence is this, with 1G occurring just after 0.3M then 4G should be occurring just after 0.6M, instead of 0.75M, if the Clmax was constant at this altitude.

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 16:22
by garrya
sprstdlyscottsmn wrote:Everything below 14k is the same and everything above 20k is the same

But it said the auto program is adjusted for altitude biasing, doesn't that mean it will operate using information from the pitot tube?

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 16:38
by f-16adf
"Furthermore things are what they are, all the information we need has already been exhaustively tested and charted out, so there's really no need to be making guesses or claims about anything."

I ascertained that was directed towards me, that is why I include my diatribe about your "estimations" vs my own.


Exactly, you can draw the line out to 9G, but technically do not know its actual parameters on the curve. Neither you nor I have ever flown for VX-4 or are actual fighter pilots.


This original discussion thread never included any F-15 posted data. Go back to pg 1-3 and look. No F-15 charts.

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 16:57
by f-16adf
Magnum is talking about entire turn circles. You are getting that confused with instantaneous turn radius (your initial "max lift" turn pull). That sounds a little goofy, but i'm at my desk, so excuse my odd composition.



Here is the F-14B at 10k.

http://imgur.com/a/nuDmP



Here is the heavies of the GE vipers, the Greek Block 50 at 10K.


http://imgur.com/a/2r745




For the initial (meaning the beginning of the turn), the Block 50 is on its CAT 1 limiter. The Tom is not. The first few seconds of the turn (I will call it instantaneous turn radius), the Tom is superior. No disagreement here. :D


However, lets examine them both doing 5g sustained turns:

The Tom at 5g, 13.9DPS, at almost .6 Mach, has a sustained turn radius of a little over 2700ft. The B 50 at 5g, 13.3DPS, around .65 Mach has a sustained turn radius of 3100ft. Remember at .61 Mach the Tom has its BEST STR of 14 or 14.1 DPS.


It's hard to tell exactly tell, but for a 6g sustained turn, the Tom has a sustained turn radius of 4000ft. The B50 at 6g has a sustained turn radius of 3500ft.

At 7g the B50 is at 14.2 DPS, yielding a 3750ft radius.


With the benefit of the corner plateau, meaning, you have options-




See the trend.


And once again, the B 50 is one of the heaviest Vipers. B30 and B10 are lighter so expect smaller turn radii.




Lastly, pull out the Mirage 2000, 15k chart. See, it's great for the first few seconds; after that, the shows is all over.

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 17:02
by garrya
F-16adf,you can put the link in the image tag so the image will display

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 18:34
by sprstdlyscottsmn
garrya wrote:
sprstdlyscottsmn wrote:Everything below 14k is the same and everything above 20k is the same

But it said the auto program is adjusted for altitude biasing, doesn't that mean it will operate using information from the pitot tube?

I am pretty sure that is why there is a <14k and an >20k line in the program.

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 19:05
by garrya
f-16adf wrote:Magnum is talking about entire turn circles. You are getting that confused with instantaneous turn radius (your initial "max lift" turn pull). That sounds a little goofy, but i'm at my desk, so excuse my odd composition.
Here is the F-14B at 10k.

http://imgur.com/a/nuDmP
Here is the heavies of the GE vipers, the Greek Block 50 at 10K.
http://imgur.com/a/2r745

Come to think of it, if F-14 sustain the same turn rate as F-16 at slower speed, shouldn't the radius be smaller.?

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 20:00
by sprstdlyscottsmn
Same rate and lower speed is smaller radius, yes. That's why you don't fight your opponents fight. You don't go horizontal at low speeds with a Tomcat, you go with vertical maneuvers.

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 21:58
by f-16adf
You need to look up Gums old posts on the F-16A. He flew the very light small tails from 1979-84 at Hill AFB. I believe he said that at 9G, he had a turn radius between 1100-1200ft. Now I do not know if he was at an ACM range in that general area, or above Hills elevation of 1459ft., or sea level.


http://imgur.com/a/gMzYO


This is a small tail data sheet from 1979/80, as you can see EMPTY WEIGHT: 15,137lbs, which is 4k or more lighter than Block 50. Hence it has a FAR smaller turning radius than later F-16's.

This agrees with Mig-17 demo pilot Randy Ball's statement about the early A model Viper being the first jet to have a smaller turn circle than the Mig-17 (I posted his interview earlier). I'm sure with the wings out at 20-22 degrees the Tomcat gets pretty close, but it seems that the small tails could do better.

Randy's interview, listen at 4:45 mark:

https://www.youtube.com/watch?v=V2-LprWf3NI

I emailed CDR Chesire, who flew the F-14A against the Mig-17 in the late 1970's after his deployment with VF-1, the same question; his answer was that even with the wings forward the F-14A did not have a smaller turn circle than the Mig-17.


But once again, you keep adding weight to the jet (like the later Blocks) and turn radius will obviously suffer.




The problem is a USAF T.O. -1-1 is nearly impossible to come by for any of the A models, so I will defer to CDR Chesire and Mr. Ball's statements as fact.

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 22:25
by hummingbird
eloise wrote:I think because the charted lift is at 35k ft, the wing swept is delayed compared to low altitude
Image


By a magnitude of ~0.03* mach compared to below 14,000 ft, so it changes nothing.

*EDIT: Initially wrote 0.3 Mach which was a giant typo.

and F-14 has lower G limit than F-16.


That is just the regulatory operational load limit, and this "limit" (which isn't actually a limit, just a "regulations tell me not to") was set by the Navy based on ensuring maximum airframe longevity. The projected operational load limit was initially set at 7.5 G's by Grumman, reduced 1.5 G's from 9 G to account for the extra stresses of carrier operations. However when F-14 orders were cut short, and each airframe therefore suddenly had to last a lot longer, this was reduced first to 7 Gs and then later 6.5 G's by the Navy.

In terms of actual airframe strength the F-14 is no more limited than the F-15, both aircraft featuring the same ultimate load limit. In truth Grumman could even pride themselves with abit more assurance as to this limit as it was derived from an unprecented amount of airframes tested, Grumman subjecting more F-14 airframes to stress tests during development than with any other US aircraft before and I think also since.

Utlimately though, as any fighter pilot will tell you, in a life or death dogfight G limits don't exist and you pull as many G's as you can endure to ensure you get out of there the victor. In the case of the F-16 this is just an enforced 9 G by the FCS.

Current F-14 has retired


I know, hence the "" ;)

In other words I was comparing the usual 2000's F-14, F-16 & F-15.

Re: F-16C, F-16E vs F-14D

Unread postPosted: 22 Aug 2017, 23:24
by f-16adf
Garrya,

What link are you referring to? I might have missed something?

Re: F-16C, F-16E vs F-14D

Unread postPosted: 23 Aug 2017, 01:14
by basher54321
hummingbird wrote:In other words I was comparing the usual 2000's F-14, F-16 & F-15.


Ha it's the first time I have seen the F-16 & F-14 compared together where the F-16 looks the superior BVR jet. :wink: