Energy Maneuverability a priority?

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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rowbeartoe

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Unread post13 Sep 2021, 00:40

Hi Everyone,

I hope you are all have a great day whenever you read this. I remember growing up being a fan of the F-16 and admiring not only the looks of it, but also how it represented John Boyd's energy maneuverability of the time.

One could probably argue that several 4th generation fighters post the F-16 such as the Mig-29, Jas-39 Gripen, ef-2000 among others would all do well with Energy Maneuverability.

I'm not an expert on this as my next two questions will obviously show.

I'd imagine that this "theory" isn't about slow speed fighting, otherwise wouldn't a WW I aircraft be superior to a WW II one?
Doesn't this "theory" go against the idea of slowing down for the fight simply because your aircraft handles better at slow speed?

That said, whatever the science of having extremely agile and maneuverable aircraft can bring, isn't this a low priority now with US and world future fighters?

Thank you everyone.

https://en.wikipedia.org/wiki/Energy%E2 ... ity_theory
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Corsair1963

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Unread post13 Sep 2021, 06:39

While, a slow turning fight is less likely to happen in the future. You still want the ability to fight and survive in that arena.


Like modern fighters rarely use a gun in aerial combat. Yet, most would still prefer to have it in the toolbox!
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hornetfinn

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Unread post13 Sep 2021, 09:14

Extreme agility and maneuverability are still very useful even if extended gunfights are likely to be rare. They help in getting quickly into better missile firing position. Even with modern HOBS missiles, turning the aircraft helps increase range and hit/kill probabilities.

Another important thing is that high agility/maneuverability help avoiding enemy missiles. Read for example here:
https://apps.dtic.mil/sti/pdfs/ADA136834.pdf

It's almost 40 years old document, but still totally valid.

A rapid jinking maneuver that times the last reversal to occur with about one second until impact and is done in a
plane perpendicular to the line-of-sight vector showed the largest increase in miss distance. The open loop evasion algorithm for a PN missile is simple and centers around the missile being seen by the pilot. If a launch is detected but the missile is not in view, the pilot should jink as quickly as possible and in any direction. If the pilot sees the missile he should jink in a plane perpendicular to the line-of-sight vector and time the last switch to occur about one second before impact. If the missile is already one second from impact when first seen a maximum g turn perpendicular to the line-of-sight vector should be done immediately.


Another interesting thing from that article:
One thing that can be done is to provide a system that will be able to provide accurate missile state information
for use in an automated closed loop evasion algorithm. As mentioned before, work has already been done to develop
closed loop evasion algorithms against PN guided missiles. A radar/infrared package that can track the missile in flight
and provide reliable range, azimuth, elevation, and range rate information in real time would be a big improvement. With that type of sensor information a computer and electronic flight controls the aircraft could be flown in a optimum flight path to avoid the missile. Optimum maneuvering should be able to produce two or three times the average values found for the vertical jink with the last second reversal. The type of missile tracking system suggested does not yet exist, other equipment does exist that must be used to help increase the miss distance.


EO DAS Anyone... :D I think spherical and long range MLD/MAWS s great tool for the pilot to avoid missiles. Having as much time as possible is crucial in avoiding modern missiles.

Avoiding those missiles will likely get aircraft slow too and having controllability after that would be very nice. It's good if the aircraft has enough power to get up to speed quickly. So there E-M is also totally valid. Of course it's only one part of aircraft design and there are nowadays all kinds of other stuff that needs to be considered like stealth, networking, sensors and sensor fusion, targeting capability etc.
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milosh

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Unread post13 Sep 2021, 18:48

Corsair1963 wrote:While, a slow turning fight is less likely to happen in the future. You still want the ability to fight and survive in that arena.


Like modern fighters rarely use a gun in aerial combat. Yet, most would still prefer to have it in the toolbox!


Well pilots don't think so. If you listen this podcast:
https://www.fighterpilotpodcast.com/

Guests which are from different airforces have similar view on stealth vs stealth, it would came to dogfight because radar seeker in missile isn't powerful at all to deal even with lower tech stealths. For example if RCS is just 0.05 m2 seeker similar to one in AIM-120 in ideal scenario (no massive jamming which would happen in war between titans) would be able to lock that target only from 5-10km. In case of massive jamming and of course fog of war it would be lot less. And 0.05 m2 isn't really what we consider VLO, some threashold for VLO is 0.01m2 (F-117 RCS in real situation like in 1999).

What they didn't talk about is DIRCM. So if you have DIRCM on stealth then heat seekers are lot less effective so it would be guns only :D

This is why USAF didn't bother to even get some kind of external stealthy AIM-9 pod for F-35, they concluded others will go with DIRCM (Russians already did on Su-57) so it would be waste but we still want gun which isn't nowhere near good in CAS but quite useful in dogfight especially if target don't even have gun (like Chinese stealths).
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wrightwing

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Unread post13 Sep 2021, 23:25

milosh wrote:
Corsair1963 wrote:While, a slow turning fight is less likely to happen in the future. You still want the ability to fight and survive in that arena.


Like modern fighters rarely use a gun in aerial combat. Yet, most would still prefer to have it in the toolbox!


Well pilots don't think so. If you listen this podcast:
https://www.fighterpilotpodcast.com/

Guests which are from different airforces have similar view on stealth vs stealth, it would came to dogfight because radar seeker in missile isn't powerful at all to deal even with lower tech stealths. For example if RCS is just 0.05 m2 seeker similar to one in AIM-120 in ideal scenario (no massive jamming which would happen in war between titans) would be able to lock that target only from 5-10km. In case of massive jamming and of course fog of war it would be lot less. And 0.05 m2 isn't really what we consider VLO, some threashold for VLO is 0.01m2 (F-117 RCS in real situation like in 1999).

What they didn't talk about is DIRCM. So if you have DIRCM on stealth then heat seekers are lot less effective so it would be guns only :D

This is why USAF didn't bother to even get some kind of external stealthy AIM-9 pod for F-35, they concluded others will go with DIRCM (Russians already did on Su-57) so it would be waste but we still want gun which isn't nowhere near good in CAS but quite useful in dogfight especially if target don't even have gun (like Chinese stealths).

2 way datalinks would give AMRAAM better range vs a .05m^2 target.
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rowbeartoe

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Unread post14 Sep 2021, 02:13

"This is why USAF didn't bother to even get some kind of external stealthy AIM-9 pod for F-35, they concluded others will go with DIRCM (Russians already did on Su-57) so it would be waste but we still want gun which isn't nowhere near good in CAS but quite useful in dogfight especially if target don't even have gun (like Chinese stealths)."

It should be noted that the USN and USMC do not have internal guns for the F-35B and F-35C. That said the USAF do include guns with the F-22 and F-35A. Not sure how useful an external gun would work and I'm sure other stealth fighter creators may mention the "option".
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wrightwing

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Unread post14 Sep 2021, 02:27

rowbeartoe wrote:"This is why USAF didn't bother to even get some kind of external stealthy AIM-9 pod for F-35, they concluded others will go with DIRCM (Russians already did on Su-57) so it would be waste but we still want gun which isn't nowhere near good in CAS but quite useful in dogfight especially if target don't even have gun (like Chinese stealths)."

It should be noted that the USN and USMC do not have internal guns for the F-35B and F-35C. That said the USAF do include guns with the F-22 and F-35A. Not sure how useful an external gun would work and I'm sure other stealth fighter creators may mention the "option".

The gun pod on the B/C works just fine for A/A. So far, there's been no mention of a gun option on the J-20 or J-31.
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hornetfinn

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Unread post14 Sep 2021, 09:05

milosh wrote:
Corsair1963 wrote:While, a slow turning fight is less likely to happen in the future. You still want the ability to fight and survive in that arena.

Like modern fighters rarely use a gun in aerial combat. Yet, most would still prefer to have it in the toolbox!


Well pilots don't think so. If you listen this podcast:
https://www.fighterpilotpodcast.com/

Guests which are from different airforces have similar view on stealth vs stealth, it would came to dogfight because radar seeker in missile isn't powerful at all to deal even with lower tech stealths. For example if RCS is just 0.05 m2 seeker similar to one in AIM-120 in ideal scenario (no massive jamming which would happen in war between titans) would be able to lock that target only from 5-10km. In case of massive jamming and of course fog of war it would be lot less. And 0.05 m2 isn't really what we consider VLO, some threashold for VLO is 0.01m2 (F-117 RCS in real situation like in 1999).


That's probably true when it comes to current seekers with mechanically scanned planar array antennas. Future missiles will almost certainly employ GaN AESA radar seekers with far superior performance to current missile seekers to help against both stealth and EW. Another likely scenario is that air-to-air missiles will get dual-mode IIR and radar seekers, like already used in Israeli Stunner missile. Of course, like wringwright noted, 2-way data links will also help getting missiles close enough for seeker to work well and also to attack from better angles.

Such future missiles will be a lot more dangerous against VLO stealth aircraft. Conversely it's likely that VLO stealth or better is essential trying to survive against such missiles in the future. Slightly lower signatures and EW will be basically useless.

milosh wrote:What they didn't talk about is DIRCM. So if you have DIRCM on stealth then heat seekers are lot less effective so it would be guns only :D


DIRCM works well with reticle seeker heat seekers (like R-73 or AIM-9M) and a lot less so against modern imaging infrared seekers.
https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9251/925103/Requirements-for-laser-countermeasures-against-imaging-seekers/10.1117/12.2067264.pdf

Conventional anti-aircraft infrared seekers all operate on the principle of detecting the position of a IR source (target) by modulating the field of view (FOV) to encode the track of the target. This is a fundamental susceptibility of this class of seeker that renders them vulnerable to laser jamming with DIRCM. What the DIRCM needs are two things: modulation techniques and sufficient power for a J/S of 100 – 1000. There are several DIRCM systems available that meet these requirements and provide a high degree of protection against reticle seekers.

The latest generation of IR seekers use imaging technology that discriminates the target position in a fundamentally
different manner. This class of seeker is not susceptible to DIRCM jamming. This paper examines the effectiveness of
laser jamming against imaging seekers to derive requirements for laser countermeasures against imaging seekers


Regular DIRCM which work well against reticle seekers will only act like a beacon for IIR seekers. Only laser powerful enough to physically damage the seeker at long enough distance would work reliably. Of course there are ways to protect the seeker against lasers which would require even more powerful lasers to be used for the DIRCM system.

milosh wrote:This is why USAF didn't bother to even get some kind of external stealthy AIM-9 pod for F-35, they concluded others will go with DIRCM (Russians already did on Su-57) so it would be waste but we still want gun which isn't nowhere near good in CAS but quite useful in dogfight especially if target don't even have gun (like Chinese stealths).


Stealthy pod is not really needed as couple of external AIM-9X and ASRAAM very likely have rather small effect on RCS of the F-35. Pods which would work well for LOBL and LOAL modes and have significantly smaller RCS would also be quite expensive and would degrade performance due to their added drag and weight. I doubt DIRCM had anything to do with them. I also doubt that Su-57 DIRCM would work well against IIR seekers. How would it detect and track those missiles? UV-based MLD/MAWS work well only at lower altitudes and short ranges (about 3-5 km against "normal" missiles) when the missile rocket motor is burning. Does it have enough power to damage or blind IIR seekers at relevant ranges? That would require a lot more powerful lasers than used in any current DIRCM system.
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Unread post14 Sep 2021, 22:05

I tend to agree the 9x and ASRAAM likely have minimal RCS impact, likely not enough to warrant a separate stealthy mount, pod etc.. But it is interesting that recent pics of British F-35B's carry ASRAAM, as well as reports of USMC's using the gun pod rather extensively.

They may still be working out personal preferences or more likely, certain operational mission loadouts.I've read in the past where that was left up to the squadrons, but that involved F-14's on what sounded like CAP missions near Libya. In the new stealth world, I'm sure it's a different ballgame.

As to the OP's question, I think "it depends". Not a satisfying answer I know, but context is very important... as is the question of being "a priority". Fair to say I think it's not as much of one, as it used to be...
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Corsair1963

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Unread post15 Sep 2021, 06:15

mixelflick wrote:I tend to agree the 9x and ASRAAM likely have minimal RCS impact, likely not enough to warrant a separate stealthy mount, pod etc.. But it is interesting that recent pics of British F-35B's carry ASRAAM, as well as reports of USMC's using the gun pod rather extensively.

They may still be working out personal preferences or more likely, certain operational mission loadouts.I've read in the past where that was left up to the squadrons, but that involved F-14's on what sounded like CAP missions near Libya. In the new stealth world, I'm sure it's a different ballgame.

As to the OP's question, I think "it depends". Not a satisfying answer I know, but context is very important... as is the question of being "a priority". Fair to say I think it's not as much of one, as it used to be...


I doubt the RAF and/or USMC are worried to much about a small increase in RCS at the moment. (peacetime)
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Unread post15 Sep 2021, 09:44

I think external ASRAAM/AIM-9X are going to be used in most air-to-air missions and that the effect on RCS and flight performance will be very small. F-35 with couple of external IR AAMs will still have far lower RCS than almost any other fighter. I doubt they will be used when mission involves penetrating dense IADS and attacking ground targets. There couple of internal AMRAAMs/Meteors will be used for self defence and even then only when absolutely necessary. Otherwise better to hide and avoid enemy fighters and conduct the planned mission.

When it comes to E-M "theory" it's pretty clear that it's still important concept for all new fighter aircraft:

Ps = Velocity((Thrust-Drag)/Weight)

However it's now approached a bit differently. F-104 and MiG-21 have a lot of thrust and very low drag and weight. So they are at first glance good from E-M PoV, but they have a lot of deficiencies in real world conditions. Neither has much in the way of sensors and avionics in general. Neither has much fuel and doesn't carry much weapons either. Adding reasonable weapons load and fuel, they are not that stellar any more. And they don't still have much in the way of sensors and avionics. So their combat potential was rather limited even in their heyday.

F-35 on the other hand has a lot of thrust but also fair amount of drag and weight compared to clean F-104 or MiG-21. But it has enormous amount of sensors and avionics and can carry equally enormous amount of fuel and weapons when needed. Put couple of 2,000 lb class weapons on F-104/MiG-21 and fuel to fly 500 nm radius missions and they won't get off the ground. F-35A is still a 9G, 50 degree AoA and Mach 1.6 aircraft along with all the SA and stealth etc. So in real world combat conditions it's really excellent from E-M PoV also.
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madrat

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Unread post15 Sep 2021, 10:55

So 'combat loaded' EM is more material than aerial displays.
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milosh

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Unread post15 Sep 2021, 17:01

wrightwing wrote:2 way datalinks would give AMRAAM better range vs a .05m^2 target.


It wan't becuase 2 way datalink don't fix weak seeker against VLO targets.2 way datalink guidence would be something like radio guidance which became history already with 1960s SAMs, time delay is such it came SAMs pretty useless against fast agile targets.

In fact it would be much better to use SARH mode to guide missile then to use 2 way datalink, for example like you have in modern SAMs, TVM regime (which is 2 way datalink before 2 way datalink became must have :D) and SARH mode in terminal phase. But that is not smart for VLO fighters because SARH mode would for sure reaquire higher radar emision and thus it would compromise stealth.So no wonder folks which know (pilots on fighter podcast) are pretty sure LO/VLO fights will be dogfights.


@Hortenfinn


Su-57 DIRCM (101KS-O) have smaller IRST sensor so it have IR channel too:
https://pbs.twimg.com/media/ED2iPUoU0AE ... name=small

Second sentence translated:

Capabilities of system similar as 101KS-V (that is main IRST) + blinding of missile seeker.

Also that sensor act as part of Su-57 DAS-ski system.

Btw Russians in early 2000s did play with stealthy external missiles (speacial spray coatings to reduce RCS):
https://www.fighter-planes.com/stealth2.htm

But they dump that idea and go with stealthy wing pod in case of Su-57 and in case of Su-75 classic side weapon bay.

So if Su-57 which isn't No1 stealth design have stealhy pod it is clear that carrying R-74 externally would impact its RCS noticable.

In case of F-35 is would be even worse.

Here is good math simulation about RCS of AIM-9 like missile:
https://www.scielo.br/j/jatm/a/tPfhf4dM ... df&lang=en

As you can see side RCS is huge, and it is logical fins act as excellent radar reflector when radar is lateral to missile. Rocket engine is also nice radar reflector so rear RCS is also quite compromised in case of LO/VLO fighter which carry WVR missile externally.
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Unread post15 Sep 2021, 18:17

milosh wrote:Rocket engine is also nice radar reflector so rear RCS is also quite compromised in case of LO/VLO fighter which carry WVR missile externally.


AFAIK the AIM-9X has some kind of plug in it's engine when it's carried by an F-35. This plug shields the engine from radar waves.
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Unread post15 Sep 2021, 19:37

milosh wrote:
Corsair1963 wrote:While, a slow turning fight is less likely to happen in the future. You still want the ability to fight and survive in that arena.


Like modern fighters rarely use a gun in aerial combat. Yet, most would still prefer to have it in the toolbox!


Well pilots don't think so. If you listen this podcast:
https://www.fighterpilotpodcast.com/

Guests which are from different airforces have similar view on stealth vs stealth, it would came to dogfight because radar seeker in missile isn't powerful at all to deal even with lower tech stealths. For example if RCS is just 0.05 m2 seeker similar to one in AIM-120 in ideal scenario (no massive jamming which would happen in war between titans) would be able to lock that target only from 5-10km. In case of massive jamming and of course fog of war it would be lot less. And 0.05 m2 isn't really what we consider VLO, some threashold for VLO is 0.01m2 (F-117 RCS in real situation like in 1999).

What they didn't talk about is DIRCM. So if you have DIRCM on stealth then heat seekers are lot less effective so it would be guns only :D

This is why USAF didn't bother to even get some kind of external stealthy AIM-9 pod for F-35, they concluded others will go with DIRCM (Russians already did on Su-57) so it would be waste but we still want gun which isn't nowhere near good in CAS but quite useful in dogfight especially if target don't even have gun (like Chinese stealths).


got it backwards again
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