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

Agreed, it will never be a fair fight but how would the F-16 match up against the ... ?
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garrya

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Unread post23 Aug 2017, 02:14

eloise wrote:Sound like F-14 is very similar to F-18, Mig-29. I heard the gents in F-16 said they don't want to get slow with F-18 or Mig-29. From pilots testimony, F-35 also has this characteristic.

AFAIK the corner speed for Super hornet is even slower than F-14 Tomcat.
In a BFM (Basic Fighter Maneuvers ie a dogfight) engagement, the pilot has to think about energy management. Fighter pilots always talk about a Rate vs a Radius fight, which in layman terms means how fast can you go around the circle you are turning versus how short of a radius can you make your circle. Some Fighters perform better in a rate fight while others perform better in a radius fight.

For example, if a Tomcat was in a BFM engagement with a Super Hornet, the Tomcat's best chance to win the fight (we are assuming "Sticks and Stones" meaning each fighter has only a gun remaining) is to try and force the Super Hornet to bleed off energy at the first pass. The Tomcat would force the Super to honor his nose position, make a neutral pass at the merge and then go vertical. The Tomcat's ability to add energy and head into the vertical was a serious advantage over the Super Hornet. Conversely, the Tomcat would not want to get into a slow speed fight with the Super. With both jets at slow speed, the Super has a better ability to maneuver his nose for a shot than the Tomcat.

The F-15C is probably the premier BFM fighter and more capable in that area than the Tomcat. You have to remember, the F-15C has a 9G turning capability versus 6.5 to 7.0 G for the Tomcat. But the F-15C is strictly air-to-air, so there are trade-offs in capabilities between the two jets.They don't drop bombs, we do. Another thing: a lot of success in BFM has to do with the pilot's ability to maximize the jet's capability. Fortunately, the best trained guys who fly the F-15C are on our side!

https://www.google.com.vn/amp/foxtrotal ... 043625/amp
Last edited by garrya on 23 Aug 2017, 02:35, edited 1 time in total.
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garrya

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Unread post23 Aug 2017, 02:23

f-16adf wrote:Garrya,

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

I meant you can put these links to imgur inside the [image] tag so they could display.
Regarding turn radius, i meant that if you look at charts in page 1, the Tomcat sustain around the same turn rate as F-16 but at lower speed regime. Thus, the turn radius of F-14 would be smaller.
On the otherhand, that chart is the data for the heavier F-16 block 50 and taken at DI 50 instead of 40 (pylons gone with tanks) or 32 (assuming that F-16 uses 2 missiles for BVR combat). Since lower DI mean the fighter can sustain higher G and lower weight reduce lift induced drag so i guess magnum4469 and Gums statements still make sense.

sprstdlyscottsmn wrote:
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.

In that case what happened when the altitude is in between 14k and 20k?
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f-16adf

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Unread post23 Aug 2017, 03:49

Yes, but I chose G for a reason, you could also compare them at the same speed .6 Mach, .7 Mach, .8 Mach.


F-14B at .6 Mach = 2700ft, 14 DPS
F-14B at .7 Mach = 3500ft, 13 DPS
F-14B at .8 Mach = 4100ft, 12.7 DPS


F-16C at .6 Mach = 2900ft, 12.9 DPS
F-16C at .7 Mach = 3300ft, 13.5 DPS
F-16C at .8 Mach = 3600ft, 14 DPS


(All rough estimations, sorry i'm tired and in need of sleep, I was not too precise in observing charted material)



It still concludes that the Tomcat is best at .6 Mach, which I said in my earlier post.
Additionally, after .6 Mach the Tomcat's STR and radius is on a rather sharp decline.



But my main argument is that as you keep adding weight to a jet, namely 4,000lbs. your turn radius suffers. That is what is happening to the Block 50 against the other lighter Vipers.


For example, when I fly my RG, and i'm the only soul on board; obviously it will be more nimble and responsive than when i'm with 3 passengers. It's the same air-frame, but total weight of the airplane has gone up by a few hundred pounds and its lifting agent (namely the wing) is still of the same area. Remember that Lift opposes Weight (the 4 forces). So it's wing loading has increased-


Now since I do not have the T.O. F-16A -1-1, I do not know their actual rate/radius numbers. But compare the Block 30 sea level chart to the Block 50 sea level chart. Note the Block 30's increase in rate and decrease in radius at .6 Mach. And that proves my whole point. Additionally, the radius numbers improve even more with the small tail 15Klbs. Vipers.
Last edited by f-16adf on 23 Aug 2017, 13:07, edited 3 times in total.
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eloise

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Unread post23 Aug 2017, 03:56

hummingbird wrote: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

G limits could be there to reduce airframe fractures because F-14 has to carry a big a$$ radar, swing wings or because of sea corrosion, carrier operation, whatever, i don't care, we follow the limit set by Grumman. Neither you nor I have ever flown F-14, we don't know how it behaves at 9G, how dangerous is it to over g the airframe. By the time we have the F-16block 50/52, F-14s are at the end of their services so they will be even more prone to over stress.

hummingbird wrote: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

F-15 has higher load limit.
Image
Last edited by eloise on 23 Aug 2017, 04:29, edited 3 times in total.
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f-16adf

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Unread post23 Aug 2017, 03:57

Here is an interesting article about F-14A v F-14B.


http://imgur.com/a/9rShn


and pg.2 of it,


http://imgur.com/a/vaaRZ
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eloise

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Unread post23 Aug 2017, 04:06

hummingbird wrote:By a magnitude of ~0.3 mach compared to below 14,000 ft, so it changes nothing

0.3 is a whole lot for a dogfight and we will find CLmax i
changing the entire time before Mach 0.85 if we run the math
f-16adf wrote: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.

How did F-4 pilots and F-8 pilots defeat Mig-17 :mrgreen:
Last edited by eloise on 23 Aug 2017, 04:34, edited 1 time in total.
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f-16adf

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Unread post23 Aug 2017, 04:29

They used the vertical and kept the fight above 440 knots. The Fresco was superb in the 300 knot range. Almost unbelievable. If you are in the States, try to get to an airshow that Randy Ball is flying at. His Mig-17 demo will make your jaw drop-





I use to have a 20K Mig-17 chart, but I seemed to have misplaced it. I will try and find it tomorrow.
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f-16adf

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Unread post23 Aug 2017, 12:28

Actually back in Hoser's VX-4 days (i think circa 1974) he took out an early F-14A to 8.5G:




Read this entire page:


http://imgur.com/a/KWGr6




Now VX-4 is a "test and evaluation" squadron, so I do not know how this would translate into normal squadron operational performance. But it shows that the original Tomcat A model was a good performer.
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garrya

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Unread post23 Aug 2017, 12:36

eloise wrote:How did F-4 pilots and F-8 pilots defeat Mig-17 :mrgreen:

Vertical fight it is
f-16adf wrote:They used the vertical and kept the fight above 440 knots. The Fresco was superb in the 300 knot range. Almost unbelievable. If you are in the States, try to get to an airshow that Randy Ball is flying at. His Mig-17 demo will make your jaw drop-
I use to have a 20K Mig-17 chart, but I seemed to have misplaced it. I will try and find it tomorrow.

I would also love to see the chart
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Unread post23 Aug 2017, 13:31

f-16adf wrote:They used the vertical and kept the fight above 440 knots. The Fresco was superb in the 300 knot range. Almost unbelievable.


There was a famous Cunningham / Driscoll 1 v 1 dogfight in 1972 that served as what I feel is an example of how not to do this.

90% of the time the VPAF MiG-17s had no intention of stopping for a dogfight let alone trying to dogfight an F-4J in the vertical and this might have led to the assumption the MiG-17 would never follow him up. Anyway this one did (twice) and was described and illustrated as a rolling vertical scissors.

Being in that position against a jet with 30/37mm cannon and amazing low speed handling doesn't seem the best tactic to employ to me and the MiG-17F (as demonstrated) had a fairly respectable T/W if you try to go up with one with high energy. Luckily he got away with it when the MiG broke off and ran ( and promptly got shot in the back :P ).

But the lesson seems to be that to employ such a tactic you first need a distinct energy advantage. With the F-14 in most cases communicating its energy state as Magnum stated to the other pilot meant this was a great help in not getting into situations as above.

As for turn radius - dogfights happen in a 3D plane - e.g. what is the horizontal turn radius of a jet doing a high Yo Yo? well it can be a lot smaller than any level horizontal turn. Not only that the jet low on energy below me has to defend something above him which mean expending pretty much anything left in trying to get the nose up and turn - so even if the first defense succeeds it is in no position to defend the second one.
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Unread post23 Aug 2017, 22:19

eloise wrote:0.3 is a whole lot for a dogfight and we will find CLmax i
changing the entire time before Mach 0.85 if we run the math


Hehe, indeed it would be if 0.3 wasn't a giant typo on my end ;) It is 0.03 mach, you can see by checking the sweep chart. Thus as stated it makes no difference.

G limits could be there to reduce airframe fractures because F-14 has to carry a big a$$ radar, swing wings or because of sea corrosion, carrier operation, whatever, i don't care, we follow the limit set by Grumman. Neither you nor I have ever flown F-14, we don't know how it behaves at 9G, how dangerous is it to over g the airframe. By the time we have the F-16block 50/52, F-14s are at the end of their services so they will be even more prone to over stress.


The F-14 features no limiter, so the pilot can pull as many G's as he wants, and there are plenty of cases of 12+ G's being pulled without issue. Infact 14 G's has been pulled on old airframes without failure. So to artificially limit the F-14 to 6.5 or 7.5 G's in a comparison like this would only lead to a very inaccurate result as no pilot would ever limit himself to this in a real fight. Mock fights is another matter ofcourse, and here F-14 pilots are ofcourse at a disadvantage when G's past 6.5 are required and they don't want to ruin their relationship with the ground crews ;)

F-15 has higher load limit.


Operational load limit, yes. The ultimate load limit, which is what the operational load limit is calculated from based on operational demands, is the same. The F-14 & F-15 both feature a 13.5 G ultimate load limit. Thus had the F-14 been used exclusively as land based fighter it would've recieved a 9 G operational load limit as well.

In short the F-14 airframe can take just as high a G load as the F-15 or F-16 without any issues at all.
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eloise

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Unread post25 Aug 2017, 03:12

hummingbird wrote:Hehe, indeed it would be if 0.3 wasn't a giant typo on my end ;) It is 0.03 mach, you can see by checking the sweep chart. Thus as stated it makes no difference.

The widest point is around 0.1 Mach, I think it makes a noticeable difference for sustain turn rate.
Wingsweep.png

@ 0.7 Mach @ altitude > 20k ft, the wing sweep is at 21° auxiliary flaps are extended, below 14k ft, the wing sweep is at 31-33°auxiliary flaps are retracted
@ 0.85 Mach @ altitude > 20k ft, the wing sweep is at 47.5°main flaps are extended, below 14k ft, the wing sweep is at 53-55° main flaps are retracted.

The chart provided by Garry shows the L/D ratio reduced as wings sweep back.
Image

The calculation provided by sprstdlyscottsmn shows CLmax reduced as well
Image

I also think F-15 can excess F-14 instantaneous turn rate.
Lift = 1/2 * air density *Reference Wing Area * Lift Coefficient * airspeed ^2 and Lift = aircraft weight * amount of G aircraft pulls;

Wing loading = Aircraft Weight / Reference wing area ; or we can say: aircraft weight = wing loading * wing area;
For a level flight condition; if we are to put this into lift formula it becomes;
Wing loading * aircraft G load = 1/2 * air density * Lift coefficient * airspeed^2
In other words, Lower wing loading=> smaller Cl needed.

F-15 wing loading: 41,000/608 = 67.4 lb/ft²
F-14 wing loading: 55,620/565 = 98.4 lb/ft²
F-14 has 46% higher wing loading so for an equivalent instantaneous G, F-14's CLmax need to be bigger than F-15's CLmax by 46%

NASA test shows F-15's CLmax = 1.6 at AoA 40° so F-14 needs CLmax = 2.33 for equal G, higher than what we calculated for F-14 from the lift chart.
cft.jpg

F15 Cl Cy.jpg
Last edited by eloise on 25 Aug 2017, 07:10, edited 3 times in total.
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eloise

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Unread post25 Aug 2017, 03:56

hummingbird wrote:The F-14 features no limiter, so the pilot can pull as many G's as he wants, and there are plenty of cases of 12+ G's being pulled without issue. Infact 14 G's has been pulled on old airframes without failure. So to artificially limit the F-14 to 6.5 or 7.5 G's in a comparison like this would only lead to a very inaccurate result as no pilot would ever limit himself to this in a real fight. Mock fights is another matter ofcourse, and here F-14 pilots are ofcourse at a disadvantage when G's past 6.5 are required and they don't want to ruin their relationship with the ground crews ;)

Personally, i haven't heard about the story of F-14 pilot who pulls 14G but it wouldn't surprise me, I heard that some pilots did it in IAI Kfir and Mig-21 or F-4 as well. However, in my opinion, limits are there for safety, it was carefully calculated by Grumman based on the airframe and how they are used, some pilots are very lucky to pull off these crazy stunts and get away with it but that isn't recommended for all pilots.
If we go for a comparison without any G limit then I think we also need the sustain G diagram for F-15, F-16 with V-max switch engaged (102% engine thrust instead of 97%). There are many restricted maneuvers that more impressive than over G the aircraft. In one documentary that was posted here, one F-4 pilot backflip to make Mig-17 overshot. I will try to find it.

hummingbird wrote:Operational load limit, yes. The ultimate load limit, which is what the operational load limit is calculated from based on operational demands, is the same. The F-14 & F-15 both feature a 13.5 G ultimate load limit. Thus had the F-14 been used exclusively as land based fighter it would've recieved a 9 G operational load limit as well.

In short the F-14 airframe can take just as high a G load as the F-15 or F-16 without any issues at all.

Where did you get the ultimate load limit for F-14, F-15 and F-16?
Last edited by eloise on 25 Aug 2017, 05:06, edited 1 time in total.
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Unread post25 Aug 2017, 05:01

eloise wrote:one F-4 pilot backflip to make Mig-17 overshot. I will try to find it.

This documentary?
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Unread post25 Aug 2017, 05:23

eloise wrote:The widest point is around 0.1 Mach, I think it makes a noticeable difference for sustain turn rate.
Wingsweep.png

@ 0.7 Mach @ altitude > 20k ft, the wing sweep is at 21° auxiliary flaps are extended, below 14k ft, the wing sweep is at 31-33°auxiliary flaps are retracted
@ 0.85 Mach @ altitude > 20k ft, the wing sweep is at 47.5°main flaps are extended, below 14k ft, the wing sweep is at 53-55° main flaps are retracted

You can see retracted and extended envelope of maneuver flaps from graph below:
Image
At sea level, maneuver flaps are fully extended below Mach 0.51, partially retracted from Mach 0.51 till Mach 0.58 and fully retracted at higher speed
At 35K ft, maneuver flaps are fully extended until Mach 0.86, partially retracted from Mach 0.86 till Mach 0.87 and fully retracted at higher speed
Difference of approximately 0.3 Mach between sea level and 35K ft.
P/S: Come to think of this, since maneuver flaps start to be retracted at some specific wing sweep, does this mean wing fold back sooner at sea level than at 14k ft?
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