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Why did this aircraft have so much trouble...
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You are currently reading a thread in /k/ - Weapons

Thread replies: 58
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Why did this aircraft have so much trouble up until Desert Storm and then suddenly become our most effective aircraft of the war?
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Jews.
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Weaponry caught up with the delivery platform.

Doctrine up until just before then was high speed ingress at low altitude for accurate hits with unguided bombs.

As Paveway laser guided bombs came into wider use, the F-111 became the best option to put them on. Strategic bombers were still for carpet bombing, with long range cruise missiles just coming into service. The newest F-16s were just getting LANTIRN pods at the time, and didn't have a high enough payload compared to the F-111.

The F-111 was able to carry a large number of guided bombs, and actually had crews that had trained with them. It had the payload, range, speed, and survivability for deep strike missions.
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>>28926541

Out of curiosity, what was the "trouble"? I know the planned carrier variant failed, but was there something else?
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>so much trouble up until Desert Storm
Uh, what?
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>>28926940
>>28926944
Not entirely sure what he's talking about, although I know compressor stalls were a problem in early variants and they went through several engine inlet designs over the course of production.
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>>28926940
It was envisioned to do a lot of things but failed to do a majority of them. It was supposed to dogfight but would do so sluggishly. It was supposed to fly off carriers but the carrier variant had issues. All sorts of technical problems really punished the reputation of this craft who shined in its strike role. ECM, precision strikes, anti-tank strikes during the Gulf War.
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>>28926940
The F-111 had numerous problems during its development and service life, including its overly complicated ejection seat mechanism, its ostensively heavy weight (see its early trials with the Navy), and its terrain navigation system which was part of why it was aptly named "Widowmaker".
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>>28927018
>It was supposed to dogfight but would do so sluggishly
No, that was never the case. It was supposed to be a long-range strike aircraft and fleet defense interceptor. Actual fighter operations were never part of the program.
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>>28927018

Imagine if they had stuck with the idea and America had multiple decades of just F-111's in every role. America would have the most long-range fighter fleet for all of history.
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>>28927087
They tried doing fighter platform missions with the F-111 during Vietnam, though.
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>>28927110

With what weapons? Sparrow?
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>>28927110
>They tried doing fighter platform missions with the F-111 during Vietnam, though.

On the F-111 documentary I watched on it, they only did strike missions in Vietnam, and only as part of combat trials. They were effectively testing them while in actual combat.


>>28927018
>It was supposed to fly off carriers but the carrier variant had issues

Actually I have read that it trapped easily, its just that like you said, it was terribad at close in ACM. It actually was "better" at the fleet interceptor role than the tomcat. It could loiter longer, and go faster, but sucked at dogfighting.

Hence, the F-14 project.
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>>28927110
No, they didn't. The F-111A was never rated for any air to air weapons, and it never even carried a cannon operationally. It wasn't until later models (F-series IIRC) that the F-111 was even wired for AIM-9s, and they never had any avionics for air-to-air duties.
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>>28927198

The reason the carrier version was scrapped had nothing to do with dogfighting. It had to do with the fact that the airframe simply weighed too much and so it needed too long of a runway to be safely operated from an aircraft carrier.
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>>28926840
Also, the F-111D could actually carry the PAVE TACK in the bomb back, where the F-16 could not and the F-15E had to carry externally.

Because LANTIRN was just coming up there was a shortage of laser designators, so the F-111Ds, as the only baseline targeting pod equipped all weather capable tactical strike fighters got a lot of business.
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>>28926940
Also, flyaway cost per unit was up to 103 MILLION DOLLARS in the 1960's. So it cost more than an F-35A currently does at a time when the A-6, a moderately expensive all weather attack aircraft, cost only 9 million dollars. All this for a very poor combat performance in Vietnam.
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>>28927006
>Compressor stalls
Man, how could GE have gotten SO far off the mark with the TF-30?
>>28927198
>It could loiter longer
Metric fuckloads of fuel will do that...
>and go faster
Wat
>but sucked at dogfighting
And acceleration, which is kinda important for an interceptor.
>>28927406
LRIP is always much higher than FRP, pic related.
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>>28928000

The F-111 could go up to 1450 knots. That's Mach 2.5, equal in speed to the F-15 Eagle. The F-14 couldn't do that. Probably takes a while to build up to that speed, though.
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>>28928000
IIRC the big problem that was causing the compressor stalls on the F-111 was actually more due to the inlets causing the ingestion of boundary layer air.
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>>28928047
Setting aside the fact that supersonic fighters NEVER get to mach 2 in the real world outside of flight testing....
https://en.wikipedia.org/wiki/General_Dynamics%E2%80%93Grumman_F-111B#Specifications_.28F-111B_pre-production.29
>Top Speed: Mach 2.2
The F-14's top speed was higher than that of the naval F-111B.
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>>28928154

>Setting aside the fact that supersonic fighters NEVER get to mach 2 in the real world outside of flight testing....

*raises eye-brow skeptically*
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>>28928087
Well, yes, that's effectively the aggravating factor at play, but the TF-30 had a very poor tolerance of it. It happened to the TF-30 on both the F-111 AND the F-14, but once the F-14 adopted the F110 engine instead, the problem virtually disappeared.
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>>28928201
They don't. Reaching those speeds requires a prohibitively-tremendous amount of distance and fuel, and not to mention can only occur at impractically-high altitudes. The ONLY time it ever actually happens is during high-altitude recon missions were the entire flight is planned out in advance.

Oh yeah, and the aircraft must be aerodynamically clean to do it, too.
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>>28928302

Good to know.
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>>28928201
Getting to 750 meters a second takes a long time accelerating in afterburner. You can do it, but it means getting very high, then burning all the fuel you can carry at once, more or less.

Getting to 450 meters per second is more reasonable. Gives a lot of velocity for weapons to build on and lets you get where you want to be in a huge hurry
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>>28926541
The Air Force ironed out its problems over the course of decades, and PGMs became a thing. The F-111 was wired for them, and performed quite well with them.
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>>28928371

So I guess the takeaway here is that being able to accelerate quickly is more important than top speed. But don't the two go hand-in-hand? Would a jet with a lower top speed but high acceleration be the ideal? Would such a thing even be possible?
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>>28928516
>Would such a thing even be possible
Yes.
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>>28928516
>But don't the two go hand-in-hand?
Not necessarily. Inlet design starts to be really important at higher Mach numbers, so without variable geometry inlets, it doesn't really matter how must thrust your engines are rated for.

Acceleration, on the other hand, is just a function of thrust-to-weight ratio. So while, through careful aerodynamic design, you might be able to go incredibly fast, that doesn't mean you'll accelerate to that speed quickly.

An extreme example would be the SR-71 compared to the F-16. The F-16 has a top speed half that of the SR-71, but it's got a far better thrust-to-weight ratio, so it'll be accelerating far faster.
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>>28928583

That's very informative. So you could design the inlets in such a way that the fighter will not go above a particular speed, say Mach 1.75, regardless of thrust?
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>>28928516
>So I guess the takeaway here is that being able to accelerate quickly is more important than top speed.
Yes.
>But don't the two go hand-in-hand?
Not really. The chief limiting factor on these afterburning fighters tends to be a combination of thermal effects and inlet design. Look at the SR-71 - titanium airframe and nickel superalloy engines, plus incredibly sophisticated variable-geometry inlets allowed it to accelerate to mach 3.3+, but it's thrust:weight ratio was less than 0.5. Or the MiG-25, or XB-70 for that matter - steel airframes and variable-geometry multi-shock inlets in both cases.
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>>28928621
Well no. You could design an engine that wouldn't be able to 'breath' and thus function at higher speed then that, but it could still exceed that speed in a power dive or by using some kind of auxiliary rocket. Those would be terrible ideas.
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>>28928621
>regardless of thrust
Inlet design limits how effectively you can ingest, and subsequently compress and combust air, and thus limits available thrust. Inlet drag is
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>>28928411
>PGMs became a thing. The F-111 was wired for them

*Cough* Carpet Bombing for decades *Cough*
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>>28928621
It's more that you need to manage airflow into the engine at higher speeds.

You need special inlets for the magic that is compressible aerodynamics. Generally, the limit for simple fixed inlets seems to be around Mach 1.6. Beyond that, you're either using variable geometry inlets, movable shock cones, or some magical shaping that somehow works at high supersonic speeds without fucking up the flow at low speed as well.
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>>28928754

So THAT's why the F-35 has a top speed of 1.6 despite it's ginormous engine.
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>>28928746
I'm not sure what you're trying to say here.
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>>28928769
Yup. Static inlets that are easier and cheaper to design.

It's also why the MiG-23 is significantly faster than the MiG-27 - the former has special inlets while they're static on the latter.
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>>28928754
Why did the Mig-25 get away with its inlets?
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>>28928852

I've read test pilots saying that the F-35 has far superior acceleration to the F-16, yet it has a slower top speed. It never made sense to me. Now I can explain it.
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>>28928861
The MiG-25's inlets are variable-geometry 4-shock inlets. Also they're fucking huge.
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>>28928000
>LRIP is always much higher than FRP, pic related.
Anon. 103 million apiece flyaway. in 2015 dollars, that's 775.18 MILLION apiece. Each F-111 cost more than a B-2 in 1997 in then year dollars.
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>>28926559
Care to elaborate on that anon?
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>>28928516
>Would a jet with a lower top speed but high acceleration be the ideal? Would such a thing even be possible?
Yep
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>mfw we retired them
>F-35s and F-18s don't have the range to reach Malaysia in case of happening
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>>28932090

Why were they retired?
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>>28926541

>Dat range
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>>28932168
Too expensive to fly, burgers weren't providing replacement parts anymore

This is what the gov thinks about long range strike capability
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>>28932090
you mean f-16? f-18 would just launch from a carrier off the coast.
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>>28932225

>Australia
>Carriers
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>>28932225
Funny guy
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>>28932168
Insane maintenance costs/times.
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>>28927110
>They tried doing fighter platform missions with the F-111 during Vietnam, though.

On the F-111 documentary I watched on it, they only did strike missions in Vietnam, and only as part of combat trials. They were effectively testing them while in actual combat.


>>28927018
>It was supposed to fly off carriers but the carrier variant had issues

Actually I have read that it trapped easily, its just that like you said, it was terribad at close in ACM. It actually was "better" at the fleet interceptor role than the tomcat. It could loiter longer, and go faster, but sucked at dogfighting.

Hence, the F-14 project.
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>>28928047
Now I cannot find a source at this min, but I have read on multiple occasions that despite what it lists on wikipedia, the F-14A did mach 2.43 in testing with the shitty TF-30 engines, and was still accelerating.

On the other hand, I have never heard of an F-15 actually achieving mach 2.5 on any flight.

Either way, 0.1 to 0.2 mach is hardly a huge deal.

>>28928154
>>28928201
>>28928302
The F-14 and the F-111 were actually some of the fastest aircraft with weapons loadouts.

The F-111 because it had an interanl bomb bay ( though to be fair it was only really ever used for nuclear payloads), and the F-14 because of the tunnel between the engines. The tunnel was essentially an internal bomb bay, weapons put there were in a very low drag installation.

But yeah, when you add weapons and pylons to fighter jets, they incur massive drag penalties. One aircraft famous for this is the F-18. With a FULL stores loadout, the motherfucker can barely break the mach. The Viper isnt exactly a rocket ship either with two wing bags and a pair of 2k lb jdams.

This is why the F-35 vs F/A-18 argument isnt even close.
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>>28932212
Sad as it is, it was part of the end user certificates we bought them with - we were contracted to destroy them on retirement.
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>>28932735
Hence why a number of them are preserved whole in RAAF museums.

God knows why you're making shit like this up. They put them in landfill because preserving all of them was too expensive.
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Here, because I love you cunts and I love the F111

https://youtu.be/_WpPO9_Zed0

https://youtu.be/R7p5kWPl7Xw
Thread replies: 58
Thread images: 13
Thread DB ID: 519801



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