The F-35 Thread

[Pilotasso]

Deterrent Sparrow shots were indeed a tactic used even in Vietnam to force the enemy to a position of weakness pre-merge.

 

By using TV outside a regular trajectory the range is reduced to 1/3, there's environmental factors to consider (clouds are black body to infra red spectrum) and these are 2 weaknesses that popped up in my head. Who knows?

[Emu]

Raptor says 'hi' from your left 8 at half a mile. See ya! :megalol:

 

IMO, WVR will happen, gun fights might even happen, but until the other guy gets his own 5th gen with comparable SA building capabilities...Head on passes ain't happening.

Wouldn't happen even with a stealth aircraft. IRST won't be blind to a stealth aircraft at 10nm.

 

By using TV outside a regular trajectory the range is reduced to 1/3, there's environmental factors to consider (clouds are black body to infra red spectrum) and these are 2 weaknesses that popped up in my head. Who knows?

No idea what that means. IRST picks up jet at 10+nm, cues ASRAAM, fire. Not all clouds are black body to IR at all wavelengths 3 to 11 µm.

Edited May 3, 2016 by Emu

[Boagrius]

No idea what that means. IRST picks up jet at 10+nm, cues ASRAAM, fire. Not all clouds are black body to IR at all wavelengths 3 to 11 µm.

 

Not to mention AIM120D. Even with the range penalty of HOBS shots, the slammer should make that sort of distance COMFORTABLY (ie. pK is still "good"). Even if that shot misses for some reason you can then take another one with the nose appropriately pointed while the target has been busy defending the first one.

Edited May 3, 2016 by Boagrius

[Emu]

Not to mention AIM120D. Even with the range penalty of HOBS shots, the slammer should make that sort of distance COMFORTABLY (ie. pK is still "good").. Even if that shot misses you can then take another one with the nose appropriately pointed while the target has been busy defending the first one.

True but I was assuming amazing enemy EW had rendered all radar homing missiles useless, just for the sake of proving that even then a dogfight won't happen.

[Boagrius]

Haha fair enough. It will be interesting to see what guidance package will find its way onto SACM. I suspect it will be optimised to cope with this kind of scenario quite handily.

Edited May 3, 2016 by Boagrius

[GGTharos]

True but I was assuming amazing enemy EW had rendered all radar homing missiles useless, just for the sake of proving that even then a dogfight won't happen.

There's nothing stopping the stealth fighter from approaching from a direction that you're not looking in. IRST is not magical, is a secondary sensor.

 

Btw I'm assuming the magical EW has disabled your RWR, although that's really just not necessary :D

 

There are also air force papers out there showing that stealth reduces reaction time so much dealer the presence of IRSTs that your dogfights will happen whether you want them or not.

[Ktulu2]

There are also air force papers out there showing that stealth reduces reaction time so much dealer the presence of IRSTs that your dogfights will happen whether you want them or not.

 

Do you have a link or an explanation for that? I trust you, but I just don't see why something optimized for absorbing radiowaves would be as good in IR.

[GGTharos]

Because it's also optimized in stealth for IR. A lot of people don't know that stealth aircraft tend to be actively cooled.

I don't have a link but if you're able to access dtic.mil you'll probably find something there, OR it might have been a RAND study. Unfortunately I just don't remember :(

[Boagrius]

There's nothing stopping the stealth fighter from approaching from a direction that you're not looking in. IRST is not magical, is a secondary sensor.

 

Pretty sure he was referring to EODAS, which acts as a 360 degree spherical IRST, especially at WVR ranges. While yes, VLO aircraft do possess sig reduction (eg. the F35's recessed LOAN nozzle, "Topcoat", fuel cooling etc.) in the IR spectrum it strikes me as unlikely that any of the F35's likely future opponents would have IR reduction measures capable of getting them to within 10nm without detection...

Edited May 4, 2016 by Boagrius

[Ktulu2]

That's fine, I just wondered haw that could be, thanks for explaining!

[Beamscanner]

No technology is perfect. It's how we use what we have that's important.

 

The F-35 will prove a useful tool.

Edited May 4, 2016 by Beamscanner

[Nerd1000]

Because it's also optimized in stealth for IR. A lot of people don't know that stealth aircraft tend to be actively cooled.

I don't have a link but if you're able to access dtic.mil you'll probably find something there, OR it might have been a RAND study. Unfortunately I just don't remember :(

You may be thinking of active cooling for electronic systems inside the jet. AFAIK this relies on the fuel system: essentially the aircraft uses the fuel tanks as heat sinks. From there the heat is dumped into the combustion chambers of the engine(s). This is necessary because it's pretty hard to cool your CPU with 800 km/h airflow.

 

You can actively cool the surfaces of the jet if you want, but nothing will hide the plume of >800 degrees C exhaust gas that you're shooting out of your tailpipe. The only thing you can do is put something between the IR source and your enemy- hence the YF-23's exhaust trenches, intended to reduce its IR signature when viewed from below. I'm fairly certain that modern imaging IR sensors are good enough to see the plume expanding out behind your jet even if you are flying straight towards the sensor with your fuselage blocking line-of-sight to the exhaust itself- so sneaking up on the F-35 will be challenging, to say the least. That's not to say it won't happen, of course.

[GGTharos]

Ever heard of supercruise? :)

 

Contrary to popular belief, no IRST is magical.

 

You can actively cool the surfaces of the jet if you want, but nothing will hide the plume of >800 degrees C exhaust gas that you're shooting out of your tailpipe.

[Nerd1000]

Ever heard of supercruise? :)

 

Contrary to popular belief, no IRST is magical.

600-800 degrees C is for 'dry' exhaust. Light up the afterburner and you're looking at exhaust temperatures greater than 2000 degrees C. For this reason, afterburner designers go to great lengths to direct a portion of the exhaust from the back of the turbine into a perforated liner on the inside of the tailpipe. This liner distributes the gas around to cool and insulate the tailpipe and nozzle while the afterburner is running- otherwise those parts would melt in the heat of the afterburner flame.

 

IRST isn't magic, but a jet engine is a really strong IR source. This is unavoidable because of the laws of thermodynamics. What saves you from being seen at massive BVR ranges is the fact that air absorbs IR radiation, particularly in certain parts of the spectrum.

[Emu]

There's nothing stopping the stealth fighter from approaching from a direction that you're not looking in. IRST is not magical, is a secondary sensor.

 

Btw I'm assuming the magical EW has disabled your RWR, although that's really just not necessary :D

 

There are also air force papers out there showing that stealth reduces reaction time so much dealer the presence of IRSTs that your dogfights will happen whether you want them or not.

Possibly but it's fairly wide angle, covers the entire frontal hemisphere with estimated 50km range against 'cooler' IR optimised fighters, and I was really assuming stealth vs stealth or non-stealth vs non-stealth or stealth vs non-stealth. A stealth aircraft would likely choose not to get that close anyway, it doesn't make any sense to.

 

RWR is passive, so EW doesn't really work on it. Some RWRs may struggle against AESA, some may not.

 

I'm dubious about the last point, it surely wouldn't apply to F-35 with EODAS as well as IRST.

Edited May 4, 2016 by Emu

[Emu]

Because it's also optimized in stealth for IR. A lot of people don't know that stealth aircraft tend to be actively cooled.

I don't have a link but if you're able to access dtic.mil you'll probably find something there, OR it might have been a RAND study. Unfortunately I just don't remember :(

I believe they have reduced IR signature certainly but not by anywhere near as much as the RCS is reduced because it's simply impossible for something moving through the air that fast with jet engines.

 

Ever heard of supercruise? :)

 

Contrary to popular belief, no IRST is magical.

IR reduction is not magical either. Supercruise doesn't stop skin friction, nor does it eliminate all exhaust heat. IR systems can spot things like jeeps, infantry and even small animals, so a huge aircraft moving at 600+mph through the air with jet engines will be a piece of cake by comparison, especially when the ambient temperature is minus several dozen degC.

Edited May 4, 2016 by Emu

[GGTharos]

Possibly but it's fairly wide angle, covers the entire frontal hemisphere with estimated 50km range against 'cooler' IR optimised fighters, and I was really assuming stealth vs stealth or non-stealth vs non-stealth or stealth vs non-stealth. A stealth aircraft would likely choose not to get that close anyway, it doesn't make any sense to.

 

You can estimate that range yourself ... but it's an estimate. Whether it will be 50km or some other km depends on a lot of things. The further your detection range, the more difficult it becomes to cover a lot of sky.

 

RWR is passive, so EW doesn't really work on it. Some RWRs may struggle against AESA, some may not.

Yeah, EW really works on RWRs. Just because it's passive doesn't mean you can't do things to it.

 

I'm dubious about the last point, it surely wouldn't apply to F-35 with EODAS as well as IRST.

For the F-35, you have more warning for things approaching from interesting angles. The range at which you can detect them is anyone's guess ... the EODAS resolution is a bit lower than that of the human eye, and building a track may take time. Certainly better than seeing nothing :)

[MegOhm_SD]

Static display at the Udvar Hazy Air and Space Museum at Near Dulles.

[Emu]

You can estimate that range yourself ... but it's an estimate. Whether it will be 50km or some other km depends on a lot of things. The further your detection range, the more difficult it becomes to cover a lot of sky.

No, it scans automatically.

 

Yeah, EW really works on RWRs. Just because it's passive doesn't mean you can't do things to it.

Passive stuff just looks for the direction and position of incident radiation. The more crap you send it the better.

 

For the F-35, you have more warning for things approaching from interesting angles. The range at which you can detect them is anyone's guess ... the EODAS resolution is a bit lower than that of the human eye, and building a track may take time. Certainly better than seeing nothing :)

EODAS resolution lower than human eye? Surely range is superior.

Edited May 5, 2016 by Emu

[Mike5560]

Many things that are passive can be jammed, like radio frequencies, GPS receivers, IR missile seekers, Electro Optical devices....etc.

[PiedDroit]

Passive stuff just looks for the direction and position of incident radiation. The more crap you send it the better.

Not true, a saturated RWR won't be able to get accurate direction.

That kind of sensors have reception lobes that can pick up a strong signal and give false indications.

[Emu]

Not true, a saturated RWR won't be able to get accurate direction.

That kind of sensors have reception lobes that can pick up a strong signal and give false indications.

It will because all the radiation is coming from the same point. Just to put things in perspective, there's even such thing as passive radar.

 

Many things that are passive can be jammed, like radio frequencies, GPS receivers, IR missile seekers, Electro Optical devices....etc.

That's the active signal that's being jammed though. You can tell where the jamming is coming from but it doesn't help you get the GPS info.

 

If you're talking about DIRCM, then yes it can jam IR with a laser, but an LWR would still be able to pin-point that signal.

 

I'm sure if it were that easy to jam missiles, including IIR, nobody would bother investing in them.

 

Please note that I'm not arguing about which plane will win, just making the case that one or other is bound to destroy the enemy head-on, pre-dogfight.

Edited May 5, 2016 by Emu

[Pocket Sized]

Sorry to interrupt the current weapon discussion, but I have a few questions about the plane itself.

 

I've heard some people say the F-35 is lacking in engine power. Yet (it would appear) it can hover on military power. AFAIK modern fighters can barely reach a thrust:weight of 1.2:1 while at full AB.

 

It isn't considered a VTOL because it would be too heavy to take off while carrying any sort of useful payload right?

[Nerd1000]

EODAS resolution lower than human eye? Surely range is superior.

Depends on conditions. It might well have a shorter detection range than the human eye (with caveats- see below) in broad daylight.

 

I should note at this juncture that the human eye only has high-resolution imaging in the central 3 degrees or so of its field of view. Its resolution outside that narrow region is not good enough to read this post, which is why your eyes are scanning along this line from left to right instead of staying focused on the middle of the screen.

 

There is also a blind spot (around 12 degrees to the side and 1.5 degrees below the centre of your FoV) corresponding to the place where the optic nerve passes through the retina (because the nerve cells that pick up signals from the retina are rather illogically positioned in front of the light sensitive cells). AFAIK you don't normally notice it because your brain 'fills in' the blind spot using information from the other eye.

[Emu]

Sorry to interrupt the current weapon discussion, but I have a few questions about the plane itself.

 

I've heard some people say the F-35 is lacking in engine power. Yet (it would appear) it can hover on military power. AFAIK modern fighters can barely reach a thrust:weight of 1.2:1 while at full AB.

 

It isn't considered a VTOL because it would be too heavy to take off while carrying any sort of useful payload right?

It only has hover capability with a partial fuel load, e.g. at the end of a mission. And it only has hover capability when the lift fan is active, which raises dry thrust from 34,000lbf to about 41,000lbf. With AB it's T/W is below 1 but then the A and C variants carry a lot more fuel than typical fighters. With a 30% fuel fraction, T/W goes above unity (about 1.03 for the A model). For comparison a GR9A's T/W was well over 1.5 dry but then a GR9 didn't have room for that much internal fuel, weapons, built-in avionics etc.

Edited May 5, 2016 by Emu