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Sturgeon's House

Bash the F-35 thred.


Belesarius

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My opinion on the F-35, is the same as the Bradley

 

It's being forced to do alot that other vehicles can do better, and of-course has to make sacrifices

 

But the amount of high performance tech Americans can still shove into a piece of hardware, as blotted and inefficiently priced as it might be, will continue to make it a major threat 

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I keep seeing a lot of repeated memes about the F-35's deficiencies that seem... in want of critical review.

 

 

1)  The F-35 bleeds energy badly during turns

 

Perhaps this is true compared to an SU-27.  However, compared to a competitive model that a potential JSF buyer might want instead, it is unclear to me how this is a problem.  Because, while the F-35 may bleed energy badly during turns, the Eurocanards probably bleed energy much worse.

 

One of Pierre Sprey, and other military reformer's talking points is that fighter maneuverability is essentially a function of wing loading; that is, the mass of the fighter divided by the area of its wings.  Wing loading is very informative when discussing instantaneous turn rates, but not particularly informative when discussing sustained turn rates.

 

A fighter performing a turn first rolls until the top of the fuselage is pointed in the direction of the turn, and then pulls its nose up towards the intended direction.  The angle of attack increases, which increases the lift force acting on the fighter, and this force accelerates the fighter around the turn.

 

Increasing the angle of attack increases the drag acting on the fighter, so it begins to slow down.  The drag increases for a number of reasons, not the least of which is that the fuselage isn't aligned with the airflow anymore, but another very large reason that the drag increases is from induced drag, or vortex drag.  This is the drag caused by the vortices of air that spill over the edges of lifting surfaces.

 

Induced drag is largely a function of the aspect ratio of the wing; that is, its span divided by its chord length.  The lower the aspect ratio, the higher the induced drag.

 

So, in terms of energy retention during turns the F-35 should actually do well compared to the Eurocanards because it has a substantially higher aspect ratio.

 

 

2)  The F-35's Low Observables are Poor/General Stealth FUD

 

 

Stealth technology is complicated, so it's fairly easy for charlatans like Pierre Sprey to dupe the public on its effectiveness.

 

One idea that gets trotted out perennially is the idea that long-wave radar will invalidate stealth.  While it's true that low-observables techniques work best against shorter wavelengths, long-wave radar is only a partial counter to stealth technology because long-wave radars have very poor angular resolution (and there's nothing that can be done about this; angular resolution is a function of wavelength).  So, while a long-wave radar could pick up a stealth aircraft at greater distances than a short-wave set, it would only have a general idea of the aircraft's location rather than a precise lock.

 

Another idea that gets promoted from time to time is that Infra-Red Search and Track (IRST) sensors invalidate stealth.  IRST isn't anything new; the SAAB J-35 Draken had it on certain variants, as did some models of MiG-23.  IRST was ditched on both aircraft because it proved useless.  At least one US fighter pilot opined that the IRST on early model MiG-29s was useless too.  The resolution on more recent models has improved, so charitably granting that IRST works as advertised, does it provide a compelling stealth counter?  No.  No it does not.  It is at best a partial countermeasure.

 

IRST is a purely passive sensor that detects infrared emissions from aircraft.  The brightest emissions come from the jet engine's hot exhaust, but infrared sensors are actually sensitive enough now to pick up heat from the friction between the leading edges of the aircraft and the air, albeit at less range.  This has the advantage that, unlike radar, an aircraft being tracked on IRST does not know they are being tracked.  However, IRST cannot determine the range to a target, which makes it useless for training weapons.  At best it can cue other sensors and alert the pilot to the presence of another aircraft.  Worse still, IRST does cannot identify a target, while the latest radars have at least some means of identifying aircraft type by radar return signature.  Finally, IRST does not work well on cloudy days, as clouds absorb infrared.

 

One will occasionally see the assertion that stealth doesn't work.  This is so bizarre and wrong-headed that it scarcely needs detailed refutation.  I suppose the Iraqis manning the air defense systems over Baghdad in 1991 just decided not to shoot at the incoming F-117s because they didn't think it would be sporting or something.  It is also worth noting that the people who say this are the people who said, twenty some years ago, that radar on fighters didn't work either.  A slightly more sophisticated variant is the assertion that stealth does not work in adverse weather, which was true of first-generation stealth aircraft, but is not (at least according to Lockheed Martin), true of the latest and greatest.  Given that the F-22 and JSF use completely different radar absorbing materials than the F-117, it seems likely that getting the stuff to work in wet conditions is something they addressed.

 

Finally, one occasionally sees the complaint that the JSF's signature reduction measures are not as comprehensive as the F-22's.  This is true; the design of the F-22 pays much more attention to reducing the radar cross section from the sides and rear.  This comes at a price, however.  While there is a lot of materials black magic that goes into stealth, a lot of stealth is shaping.  Shapes that have low radar cross section are generally not shapes that make good aircraft.  The flat engine nozzles on the F-22's F119 engines, for instance, reduce both radar and IR signature, but at a considerable penalty to weight and thrust efficiency.  So, making the JSF as stealthy from the sides and rear as the F-22 could have been done, but it would have made it a less capable aircraft.

 

3)  The JSF's Helmet-Mounted Display is so bulky the pilot cannot turn their head

 

f-35b-bf-4.jpg

 

Somehow I doubt that.

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I keep seeing a lot of repeated memes about the F-35's deficiencies that seem... in want of critical review.

 

 

1)  The F-35 bleeds energy badly during turns

 

4b6.jpg

Who in the fuck care's

 

This isnt 19 fucking 40

 

Do people really think billions, if not trillions are spent on stealth technology, missiles, and computers so jets could fucking turn fight 

 

and another thing, i would understand the concern if this was a Air superiority Bird

 

But its fucking not, its made to zap anything that can out-turn it from beyond fucking visual range, and let the F-22's do the fucking dogfighting

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Sprey is irrelevant, and that comes from someone that used to take his word (with a grain of salt). 

 

His group advocated a small, lightweight fighter in the 60's and that had an influence on the F-16...but when the design was finalized, *they complained because they didn't want advanced avionics, at all*. 

 

That says it all. 

 

Aspect ratio really isn't a valid mean of judging an aircraft's' performance, for better or worse. 

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Who in the fuck care's

 

This isnt 19 fucking 40

 

Do people really think billions, if not trillions are spent on stealth technology, missiles, and computers so jets could fucking turn fight 

 

and another thing, i would understand the concern if this was a Air superiority Bird

 

But its fucking not, its made to zap anything that can out-turn it from beyond fucking visual range, and let the F-22's do the fucking dogfighting

That in itself is also an invalid argument... BVR combat is great when flying up against aircraft of significantly lesser BVR capability, but in a lot of cases it won't work this way. 

 

The F-35 is designed to link up with other C4ISR capable AWACS/ELINT to track enemy aircraft, and even fire upon them. Doing this keeps the aircraft "invisible" because it can keep its' radar system in a passive state. 

 

This is fine unless your *enemy's priority is to destroy said aircraft, and disable communications. PLAAF has stated this is how they'd work on the USAF, and certainly the same is true for RuAF.* 

 

In which case each F-35 would need to work independently, use their radar systems, and inevitably get located doing so...there goes the "stealth advantage". 

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Aspect ratio really isn't a valid mean of judging an aircraft's' performance, for better or worse. 

 

 

For sustained turn performance is definitely is.  During a sharp turn, induced drag will be a dominant source of total drag, and inversely proportional to wing aspect ratio per the equation:

 

5f067737b1ecd4663eb49c215c29838a.png

 

The only thing you've got to careful of is the fact that in most modern fighters, by design, the wing and fuselage blend together, so there's usually a blend area that is acting as a wing.  Usually, it is acting as an extremely low aspect ratio wing (deliberately), so something like the F/A-18 bleeds energy faster in a turn than you'd think it would just looking at the wings, because the LERX create big vortices (this is deliberate and has benefits).

 

 

That in itself is also an invalid argument... BVR combat is great when flying up against aircraft of significantly lesser BVR capability, but in a lot of cases it won't work this way. 

 

The F-35 is designed to link up with other C4ISR capable AWACS/ELINT to track enemy aircraft, and even fire upon them. Doing this keeps the aircraft "invisible" because it can keep its' radar system in a passive state. 

 

This is fine unless your *enemy's priority is to destroy said aircraft, and disable communications. PLAAF has stated this is how they'd work on the USAF, and certainly the same is true for RuAF.* 

 

In which case each F-35 would need to work independently, use their radar systems, and inevitably get located doing so...there goes the "stealth advantage". 

 

The APG-81 has all sorts of clever trickery that is supposed to make it difficult to pick up with RWR.  Even if it's up against very clever electronics it does get picked up, which is far from a given, getting picked up on RWR does not instantly eliminate the stealth advantage.  All the other plane knows is that something pinged them, and a rough bearing towards that thing.  They don't know who it was that pinged them, how far away it was or what direction and speed it's going; all things they would need to know to sling a BVR missile at it.

 

It's very similar to the issue with IRST before; for BVR missile engagements, there really is no substitute for an actual radar lock.

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For sustained turn performance is definitely is.  During a sharp turn, induced drag will be a dominant source of total drag, and inversely proportional to wing aspect ratio per the equation:

 

5f067737b1ecd4663eb49c215c29838a.png

 

The only thing you've got to careful of is the fact that in most modern fighters, by design, the wing and fuselage blend together, so there's usually a blend area that is acting as a wing.  Usually, it is acting as an extremely low aspect ratio wing (deliberately), so something like the F/A-18 bleeds energy faster in a turn than you'd think it would just looking at the wings, because the LERX create big vortices (this is deliberate and has benefits).

 

 

 

The APG-81 has all sorts of clever trickery that is supposed to make it difficult to pick up with RWR.  Even if it's up against very clever electronics it does get picked up, which is far from a given, getting picked up on RWR does not instantly eliminate the stealth advantage.  All the other plane knows is that something pinged them, and a rough bearing towards that thing.  They don't know who it was that pinged them, how far away it was or what direction and speed it's going; all things they would need to know to sling a BVR missile at it.

 

It's very similar to the issue with IRST before; for BVR missile engagements, there really is no substitute for an actual radar lock.

Not by itself, hence my point. It can be used to give one a general idea of the *wings'* performance, but the fuselage itself is also crucial...as are the control surfaces, TVC etc. 

 

F/A-18 is a well known energy bleeder. 

 

Currently, only the Rafale's radar system is known to be "hard to pickup". I forget how they do it, but it has something to do with a scattered frequency or something.

 

Given enough time, said variables could probably be figured out. 

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Almost all of those photos were taken at the Patuxent Naval Air Museum in Lexington Park, MD. For a summer I worked at the gun store across the street (literally) and went to see the X-32 (and X-35) every Friday.

My favorite bird they've got there is their RA-5C Vigilante. Helluva plane.

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Currently, only the Rafale's radar system is known to be "hard to pickup". I forget how they do it, but it has something to do with a scattered frequency or something.

 

 

 

APG-81 and APG-77 use exactly the same tricks.

 

It is quite reasonable to say that for a given AOA the F-35 will have less induced drag than a delta-canard.

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Delta-Canards aren't exactly known for having little induced drag, IIRC. 

 
Because of their low aspect ratios.  That is what causes that.  There is a direct causal relationship between low-aspect ratio lift-generating surfaces that create vortices and lift-induced vortex drag.
 

LPIR is great in theory, but their performance isn't going to be perfect. There have also been developments to try and defeat them. http://dtic.mil/dtic/tr/fulltext/u2/a456960.pdf

 

The ECM/ECCM race goes on, but the JSF is, astride the raptor, leading the pack, not trailing it the way many of its detractors would imply.

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