F-35 Lightning II vs Dassault Rafale

The F-35 compared with other modern jets.
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ricnunes

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Unread post13 Nov 2018, 13:41

Nice catch indeed swiss :thumb:

Actually I never noticed those saw-toothed paterns on the Rafale except for the ones inside the engine intakes. Nevertheless thanks for sharing the photos swiss!
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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ricnunes

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Unread post13 Nov 2018, 15:19

hornetfinn wrote:I really doubt that RCS goes up that significantly with modern weapons. Otherwise there would've made no sense for anybody to pay the price for developing lower RCS aircraft like SH, Rafale, EF Typhoon or even F-16 Have Glass upgrade. I think that modern weapons and even EFTs have very low RCS themselves and even added together with the aircraft, have lower RCS than without them. I agree that the have rather limited help, but everything that increases survivability is very good to have. Even somewhat lower RCS will boost survivability especially when combined with EW effects.

Of course true VLO will be totally something else when it comes to survivability.


Hi hornetfinn,

I'm not sure if I agree with your point above (or perhaps I'm misunderstanding it).
This said, I do think that external weapons and EFTs do and will always add a considerable amount of RCS. Look for example at the LO aircraft (but not exactly VLO) that are currently in development, the J-20, J-31 or Su-57. What these aircraft or any aircraft designed with LO/VLO in mind all have in common? All of them (without exception) are designed to carry their weapons internally (on internal weapons bays).
Moreover, even the LO/VLO mostly dedicated to Air-to-Air roles like the Su-57, J-20 and F-22 carry besides their main weapons bay, smaller weapons bays dedicated to the smaller (and potentially lower RCS) short-range air-to-air missiles.

Therefore I would never minimize the real impact on RCS by any external store even by the potentially lower RCS weapons/stores like short range air-to-air missiles.
And stores like EFT should have a much larger RCS than air-to-air missiles in general. Then there's also the Targeting Pod which nowadays is pretty much standard equipment for any fighter aircraft even when performing air-to-air missions. And then we have the pylons for all those stores.
So what we have here IMO, is a "RCS sum spiral" which in the end means that any aircraft than will or can only carry weapons/stores externally will end up having a quite higher (I would dare to speculate, at least two or three times more than the baseline/clean aircraft RCS).

But this doesn't mean that RCS reductions on aircraft like the Super Hornet or Rafale are "completely useless" of course. RCS reductions on aircraft like these will always help reducing the "RCS sum spiral" that I mentioned above.
For example, I'll post this academic example which does not envolve any aircraft, weapon or store in particular:
- Clean aircraft RCS: 2 square meters.
- Short Range Air-to-Air missile RCS: 0.1 square meters. If the aircraft carries two (2) so it's 0.2 square meters.
- Medium Range Air-to-Air missile RCS: 0.2 square meters. If the aircraft carries four (2) so it's 0.8 square meters.
- External Fuel Tank (EFT) RCS: 0.4 square meters. If the aircraft carries two (2) so it's 0.8 square meters.

So the aircraft above which doesn't necessarily represent a newer 4.5th gen aircraft but at the same time probably has a lower RCS (clean) than most earlier 4th gen fighter aircraft, means that it would have a total RCS of:
2 + 0.2 + 0.8 + 0.8 = 3.8 square meters

Then I'll post the example below which resembles more closely the current and more advanced 4.5th gen aircraft like the SH or Rafale which have some/considerable RCS reduction measures:
- Clean aircraft RCS: 0.5 square meters.
- Short Range Air-to-Air missile RCS: 0.1 square meters. If the aircraft carries two (2) so it's 0.2 square meters.
- Medium Range Air-to-Air missile RCS: 0.2 square meters. If the aircraft carries four (2) so it's 0.8 square meters.
- External Fuel Tank (EFT) RCS: 0.4 square meters. If the aircraft carries two (2) so it's 0.8 square meters.

So that means that it would have a total RCS of:
0.5 + 0.2 + 0.8 + 0.8 = 2.3 square meters.

I would say that's in itself a considerable reduction. For example against a radar capable of detecting a 3 square meter target at a maximum range of 350km, the first case (3.8 square meters) could be detected at a maximum range of 371km while the second case (2.3 square meters) could be detected at a maximum range of 327km (a 44 km "gain" in detection range).
Of course there's always the chance that my values above (about the stores) could be a higher than they actually are but honestly (and don't get me wrong) I don't think that they are either that low as you seem to imply. :wink:

Moreover and in line with my point(s) above I remember that Boeing planned to design "stealth pods" which could be attached to the Super Hornet's centerline and/or under the wings which were precisely intended to conceal/carry the weapons inside (the stealth pods). I would say that solution would add so much drag to the aircraft that it was abandoned (together with other initially planned upgrades for SH Block III).
Then we have (also from Boeing) the Silent Eagle concept which basically consisted in modifying the F-15's Conformal Fuel Tanks (CFTs) to carry weapons internally instead of fuel (along side with other modifications such as modified tails, etc...).~
So these 2 cases above leaves me to believe that the impact of external weapons stores, even such as air-to-air missiles is actually quite bigger than some here seem to anticipate/predict.
Well, my 2 cents antway :wink:
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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marsavian

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Unread post13 Nov 2018, 16:44

It's from the sides that vertical pylons ruin your RCS but from the front if they are angled right their effect is minimal. Enclosing all weapons in internal bays mean you have total control over all angle aspects of your RCS. Notice the SRAAM pylon of the F-35 where they have made it small and slanted to minimize the RCS impact from the side. Like you said it's a cumulative effect but the pylons type/size and whether the missiles are recessed or on wingtips make a big difference too to how cumulative that effect is. It's more subtle than your theoretical examples.
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Unread post13 Nov 2018, 19:17

Your are welcome steve2267 and Ric.

Thanks for your explanation linkomart.

hornetfinn wrote:I'm sure MBDA would like to do that, but it will require customer interest first and money for the integration. I'm sure that AESA seeker integration will happen at some point in Meteor too, but it might take some time. MICA NG is supposed to become operational in 2026, so it might be 2030+ before Meteor gets AESA seeker.

Matrix sensor sounds like normal IIR seeker (which is matrix), but with improved sensitivity and resolution. There can be really significant improvements here as MICA IR seeker technology is from 1990s and both sensitivity and resolution have gone up a lot. We are talking about potential to have at least 10 times the resolution and several times better sensitivity while reducing size and cooling requirements. I think seeker technology will improve significantly with future upgrades to all current IR seeking missiles like AIM-9X, ASRAAM, IRIS-T etc.


Thanks also for your answer hornetfinn. So still a long way to go for a AESA equipped Meteor.

marsavian wrote:It's from the sides that vertical pylons ruin your RCS but from the front if they are angled right their effect is minimal. Enclosing all weapons in internal bays mean you have total control over all angle aspects of your RCS. Notice the SRAAM pylon of the F-35 where they have made it small and slanted to minimize the RCS impact from the side. Like you said it's a cumulative effect but the pylons type/size and whether the missiles are recessed or on wingtips make a big difference too to how cumulative that effect is. It's more subtle than your theoretical examples.


Agreed. And even from the frontal hemisphere a EFT will increase the RCS clearly from a stealth Aircraft. Which is several orders of magnitudes lower then the RCS of a SH or Rafale.

@ Ric: What i don't get, why we are still talking about frontal RSC of modern missile and EFT's. Because they are studies postet by Hornetfinn, that shows that they are clearly under 0.1m2 from the front. I posted the link some pages bevor. So we talk about facts not guesses. So its very likely, that a SH or Rafale have a frontal RCS of under 1m2 with several missiles and 1 or 2 EFT.
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Unread post13 Nov 2018, 19:38

So still a long way to go for a AESA equipped Meteor.


http://aviationweek.com/defense/tests-j ... anned-2023

Japan and Britain plan to begin test shots of the advanced version of the MBDA Meteor air-to-air missile in five years, following a prototype manufacturing effort for which the two partners are now preparing. Britain will conduct the test shots, a Japanese defense ministry official says. The weapon, the Joint New Air-to-Air Missile (JNAAM), will essentially be a Meteor with a Japanese seeker with an active, electronically scanned array (AESA)


https://ukdefencejournal.org.uk/details ... an-emerge/

Details of joint missile project with Japan emerge
By George Allison - January 15, 2017
Japan and the UK are moving forward with efforts to develop a new joint air-to-air missile.

The project is understood to be supported by a successfully conducted project to integrate Japanese seeker technologies into MBDA’s Meteor Beyond Visual Range Air-to-Air Missile, IHS Jane’s has reported.

The project utilises Japanese technologies to enhance the accuracy and performance of the missile.

Meteor is an active radar guided beyond-visual-range air-to-air missile being developed by MBDA. Meteor will offer a multi-shot capability against long range manoeuvring targets in a heavy electronic countermeasures environment with range in excess of 100km.

MBDA is planning integration of Meteor on the Lockheed Martin F-35 Block 4. The Meteor has already been checked for fit in the internal weapons bays of the JSF. It is compatible with the aircraft’s internal air-to-ground stations, but would require modification of the fin span and air intakes to be compatible with the air-to-air stations.

It is understood that it is in this context, MBDA has agreed to jointly research a new seeker with Japan.

Defence Secretary Michael Fallon said:

“Japan is our closest security partner in Asia and I want to significantly deepen defence cooperation between our two nations.

We will do that through joint exercises, reciprocal access to our military bases, military personnel exchanges and cooperation on equipment, including a new air-to-air missile.”


The AESA seeker will be GaN too ..

viewtopic.php?t=53418
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Unread post13 Nov 2018, 21:11

marsavian wrote:It's from the sides that vertical pylons ruin your RCS but from the front if they are angled right their effect is minimal. Enclosing all weapons in internal bays mean you have total control over all angle aspects of your RCS.


Yes, I fully agree that enclosing the weapons in internal bays will give a "total control over all angle aspects of RCS".
I also agree that the impact on RCS by external stores is bigger from the sides compared to the front.

However I have to disagree that the RCS impact by external stores from the front is minimal even if the pylons are "angled right". Well, I do agree that if the pylons/weapons are angled correctly (like in the example that you gave about the F-35's Sidewinder pylons) that the impact on RCS will/would be lower, however I wouldn't call it minimal.

marsavian wrote:Notice the SRAAM pylon of the F-35 where they have made it small and slanted to minimize the RCS impact from the side. Like you said it's a cumulative effect but the pylons type/size and whether the missiles are recessed or on wingtips make a big difference too to how cumulative that effect is. It's more subtle than your theoretical examples.


Yes, I agree that the RCS impact is more "subtle" than my theoretical examples (like to you correctly said, they are theoretical or I would even dare to call them, "academic" examples).
However you cannot expect the aircraft to always be in the exactly precise angle towards the radar source (again I will address this further on my next reply/post).
As such I would say (or I strongly believe) that a F-35 loadout of 4 internal AMRAAMs plus 2 external ("wingtip" pylon mounted) Sidewinders will never be used on hostile environments where the F-35 will have to face enemies equipped with advanced air defense systems and/or fighter aircraft.
I would say that such F-35 loadout (4 internal AMRAAMs plus 2 external Sidewinders) will only be used when the enemy air defense systems and fighter aircraft force are severely degraded and/or more likely perhaps on policing missions where the increase of RCS isn't actually a bad thing since these are the kind of missions where the "policing asset" (F-35) says: "I'm here and I know that you know that I here, so behave" and/or an increase of RCS during such mission may also have another good side effect in which it denies the enemy the accurate knowledge of the F-35's actual RCS - Imagine those 2 external Sidewinders as some sort of expendable/deadly Luneburg lenses :wink:
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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Unread post13 Nov 2018, 21:13

swiss wrote:@ Ric: What i don't get, why we are still talking about frontal RSC of modern missile and EFT's. Because they are studies postet by Hornetfinn, that shows that they are clearly under 0.1m2 from the front. I posted the link some pages bevor. So we talk about facts not guesses. So its very likely, that a SH or Rafale have a frontal RCS of under 1m2 with several missiles and 1 or 2 EFT.


Hi Swiss,

The reason why I "insist on this" is because I honestly believe that those RCS values that you mentioned for external stores are way too low (again IMO), this for practical terms (and I would dare to say in the real world).

I even grant that you may/could get those values that you're mentioning on an exact angle in which the store (but not necessarily the aircraft itself) may be faced against the Radar source. But then again this would be more like a "spike" and not the usual RCS that you would probably get in the majority of the times when the fighter aircraft is flying towards or around the radar source.

Moreover I would speculate that there's also the chance that different weapons and stores (like EFTs) could have different "sweet spot" angles towards the radar source in terms of having its lower RCS.
And if you have different kinds of stores such as different kinds/models of missiles (even among air-to-air missiles) and other stores such as EFTs, Targeting Pods, etc... which the 4th/4.5th gen fighter aircraft always carry externally than getting that low RCS "sweet spot" will be a daunting task, to say the least! (although not impossible)

Because of the reasons above, I like/prefer to use average RCS values instead of using the RCS values regarding narrow angles.
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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Unread post13 Nov 2018, 22:55

ricnunes wrote:
marsavian wrote:It's from the sides that vertical pylons ruin your RCS but from the front if they are angled right their effect is minimal. Enclosing all weapons in internal bays mean you have total control over all angle aspects of your RCS.


Yes, I fully agree that enclosing the weapons in internal bays will give a "total control over all angle aspects of RCS".
I also agree that the impact on RCS by external stores is bigger from the sides compared to the front.

However I have to disagree that the RCS impact by external stores from the front is minimal even if the pylons are "angled right". Well, I do agree that if the pylons/weapons are angled correctly (like in the example that you gave about the F-35's Sidewinder pylons) that the impact on RCS will/would be lower, however I wouldn't call it minimal.

I was referring to the stealth of the pylons themselves but AAM missiles will have a low RCS too head-on but bombs, cruise missiles and fuel tanks much less so.


marsavian wrote:Notice the SRAAM pylon of the F-35 where they have made it small and slanted to minimize the RCS impact from the side. Like you said it's a cumulative effect but the pylons type/size and whether the missiles are recessed or on wingtips make a big difference too to how cumulative that effect is. It's more subtle than your theoretical examples.


Yes, I agree that the RCS impact is more "subtle" than my theoretical examples (like to you correctly said, they are theoretical or I would even dare to call them, "academic" examples).
However you cannot expect the aircraft to always be in the exactly precise angle towards the radar source (again I will address this further on my next reply/post).
As such I would say (or I strongly believe) that a F-35 loadout of 4 internal AMRAAMs plus 2 external ("wingtip" pylon mounted) Sidewinders will never be used on hostile environments where the F-35 will have to face enemies equipped with advanced air defense systems and/or fighter aircraft.
I would say that such F-35 loadout (4 internal AMRAAMs plus 2 external Sidewinders) will only be used when the enemy air defense systems and fighter aircraft force are severely degraded and/or more likely perhaps on policing missions where the increase of RCS isn't actually a bad thing since these are the kind of missions where the "policing asset" (F-35) says: "I'm here and I know that you know that I here, so behave" and/or an increase of RCS during such mission may also have another good side effect in which it denies the enemy the accurate knowledge of the F-35's actual RCS - Imagine those 2 external Sidewinders as some sort of expendable/deadly Luneburg lenses :wink:

Sidewinders/Asraams will only not be fitted when taking out SAM protected sites is the primary aim as VLO is crucial to the success of these missions. However they have been fitted to USMC F-35B on missions and are the default configuration of UK land based F-35B because even when fitted F-35 will still have a stealth advantage over their fighter opposition with RCS still in the 0.01-0.1 sq m range. I fully expect B and C models on CAP missions to have sidewinders and/or gunpod as default.

Last edited by marsavian on 13 Nov 2018, 22:57, edited 1 time in total.
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Unread post13 Nov 2018, 22:56

ricnunes wrote:...
...
However you cannot expect the aircraft to always be in the exactly precise angle towards the radar source ..


Pending your noting this in your next post ..

Actually you can expect precise presentation angles etc. with the F-35/22. That is sort of what the whole SA sensor fusion system is all about. Not only do they expect it .. they train for it.

Just saying,
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Unread post13 Nov 2018, 23:00

They actually have the RCS directional bat display in the cockpit to help them present their best side to opposing radars in the F-35.
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Unread post14 Nov 2018, 04:26

marsavian wrote:They actually have the RCS directional bat display in the cockpit to help them present their best side to opposing radars in the F-35.


Yep. A metric f--kton of work went into characterizing the RCS in various states, all so the pilot knows when he can be seen by what from where.
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Unread post14 Nov 2018, 07:05

marsavian wrote:The AESA seeker will be GaN too ..

viewtopic.php?t=53418


Thanks for the links marsavian. Sound indeed interesting.

blindpilot wrote:Actually you can expect precise presentation angles etc. with the F-35/22. That is sort of what the whole SA sensor fusion system is all about. Not only do they expect it .. they train for it.

Just saying,
BP


marsavian wrote:They actually have the RCS directional bat display in the cockpit to help them present their best side to opposing radars in the F-35.


I wasn't aware of this. So i understand more and more why SA and sensor fusion seems as important as stealth.

I assume 4 gen try to do the same.

@Ric. As you can see in this studys even a EFT as only from the site and RCS over -10dBsm. This means roughly 70% are lower then -10dBsm. For missiles its even smaller.
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Unread post14 Nov 2018, 07:52

ricnunes wrote:
hornetfinn wrote:I really doubt that RCS goes up that significantly with modern weapons. Otherwise there would've made no sense for anybody to pay the price for developing lower RCS aircraft like SH, Rafale, EF Typhoon or even F-16 Have Glass upgrade. I think that modern weapons and even EFTs have very low RCS themselves and even added together with the aircraft, have lower RCS than without them. I agree that the have rather limited help, but everything that increases survivability is very good to have. Even somewhat lower RCS will boost survivability especially when combined with EW effects.

Of course true VLO will be totally something else when it comes to survivability.


Hi hornetfinn,

I'm not sure if I agree with your point above (or perhaps I'm misunderstanding it).
This said, I do think that external weapons and EFTs do and will always add a considerable amount of RCS. Look for example at the LO aircraft (but not exactly VLO) that are currently in development, the J-20, J-31 or Su-57. What these aircraft or any aircraft designed with LO/VLO in mind all have in common? All of them (without exception) are designed to carry their weapons internally (on internal weapons bays).
Moreover, even the LO/VLO mostly dedicated to Air-to-Air roles like the Su-57, J-20 and F-22 carry besides their main weapons bay, smaller weapons bays dedicated to the smaller (and potentially lower RCS) short-range air-to-air missiles.


Hi, thank you for nice answer.

Actually I think we basically agree but have slightly different take on how much the RCS increases with modern external weapons and EFTs. I definitely agree that a combat loaded SH or Rafale has significantly higher RCS than a clean one. I do think that both will also have noticeably lower RCS than say Classic Hornet or Mirage 2000. Of course we are talking about very small differences compared to what VLO aircraft like F-35 achieve.

Internal weapons and fuel is also great for better aerodynamics in combat configurations and maneuverability. F-35 is Mach 1.6 and 7-9G fighter in combat configuration where all 4th++ gen fighters are subsonic or barely supersonic and restricted to less than 6G. So internal carriage is great for other purposes than RCS reduction also.
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Unread post14 Nov 2018, 08:12

swiss wrote:
marsavian wrote:They actually have the RCS directional bat display in the cockpit to help them present their best side to opposing radars in the F-35.


I wasn't aware of this. So i understand more and more why SA and sensor fusion seems as important as stealth.

I assume 4 gen try to do the same.

@Ric. As you can see in this studys even a EFT as only from the site and RCS over -10dBsm. This means roughly 70% are lower then -10dBsm. For missiles its even smaller.


4th gens can try to do the same, but their far larger and irregular RCS makes it much more difficult to calculate and display to the pilot.

Yes, EFTs have pretty low RCS. Studies seem to imply that they have -10dBsm to -30dBsm depending on angle. Of course broadside RCS can be pretty big, something like 10-20dBsm
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Unread post14 Nov 2018, 08:26

^^ Agree with both your points guys. But I just want split hairs a bit.

We all know that comparing aircraft with 8 missiles and 50% fuel is kinda dumb because light fighters will have ridiculously high T/W ratios at that configuration but at the same time will most likely be going home or will not be able to use AB as freely due to the extremely small fuel loads.

So what we did was we set up all combatants for a specific mission, lets say 300 NM away and compared T/W ratios and wing loading that way. But I don't think thats very realistic as well. Do commanders load up aircraft depending on where they think combat will take place? I don't think so.

As far as I know, all aircraft have Standard load outs. I have a copy of the USAF's F-16 standard load outs for Long range CAP, Short Range CAP, Long range Interdiction etc.

So my opinion on the best way to compare would be like this.
-F-16 loaded for short range CAP
-Gripen loaded for short range CAP
-F-35 loaded for CAP (I think an F-35 only has 1 Standard CAP load out )

Compare T/W ratios after 100 NM of travel.

Same goes for RCS.
Standard F/A-18E, Rafale and F-35 Strike load outs

Is there also a low RCS standard load where the ordnance is made up of VLO weapons like JASSM, Storm Shadow, SCALP etc.
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