USAF/US NAVY 6th Generation Fighter Programs - F/A-XX, F-X, NGAD, PCA, ASFS news

[bagera3005]

to me that fighter looks like light attack aircraft

 

[AAAdrone]

Well, it is supposed to replace the F/A-18E and F Super Hornets so it would to be designed with ground attack capability in mind. The Navy is basically attempting to resurrect the A-12 Avenger with this aircraft by the looks of it. Both A/Cs have no rudders and a level of stealth that is unprecedented as a result of the minimization of control surfaces.

That next generation bomber design looks weird. It's like something out of Battlestar Galactica or something. I've noticed a lot of complaints about the cockpit being too far aft of the front of the aircraft. I guess I can't blame them considering how hard it would be to land something like that.

 

[Ogami musashi]

This is boeing's concept for F-X, that is the successor of F-22, not the navy F/A-XX...hence it is an air dominance concept. This not because it has dorsal intakes that it means it is not good for maneuverability; Actually dorsal intakes have their share of aerodynamic advantages.

 

[sferrin]

This is boeing's concept for F-X, that is the successor of F-22, not the navy F/A-XX...hence it is an air dominance concept. This not because it has dorsal intakes that it means it is not good for maneuverability; Actually dorsal intakes have their share of aerodynamic advantages.

Compatibility with hard manuevering not being one of them.

 

[Matej]

Not entirely true... http://www.secretprojects.co.uk/forum/index.php/topic,1161.msg9332.html#msg9332

Besides, how much maneuverability do you expect from the fighter equipped with advanced short-range AAMs, tactical lasers and radar with possibility to switch to the energetic weapon mode for close dogfight? I personally expect lower emphasis on maneuverability compared to the 5th generation.

 

[Ogami musashi]

This is boeing's concept for F-X, that is the successor of F-22, not the navy F/A-XX...hence it is an air dominance concept. This not because it has dorsal intakes that it means it is not good for maneuverability; Actually dorsal intakes have their share of aerodynamic advantages.

Compatibility with hard manuevering not being one of them.

That is actually the opposite. Vortex lift fighter exhibit superior performance at high high of attack and sideslip angles with dorsal intake due to the sweeping effect of vortex of the upper region.
If you look at the Boeing design then it is evident why they produced a blended lerx all the way from the nose.


Dorsal intakes show reduction in wetted area; They also can be used as vortex generators themselves for delaying separation aft of the fuselage; They also present with shorter duct reducing skin drag;


The problem is in supersonic were they usually have higher mach numbers inside the inlet thus have shock related losses but active flow control can help that.


Canopy integration is crucial in dorsal inlets and that's why the concept you see has a blended cockpit (surely meant to be use with distributed cameras).


Northop grumman F-X concept has also dorsal intakes.

 

[sferrin]

Yeah, that's what you want, a vortex going down the intake. :

 

[sferrin]

Not entirely true... http://www.secretprojects.co.uk/forum/index.php/topic,1161.msg9332.html#msg9332

Besides, how much maneuverability do you expect from the fighter equipped with advanced short-range AAMs, tactical lasers and radar with possibility to switch to the energetic weapon mode for close dogfight? I personally expect lower emphasis on maneuverability compared to the 5th generation.

Yep, and notice they ALWAYS ended up taking them off. There are tons of ATF conceptual art out there with dorsal intakes (no brainer from an RCS POV) but then when it came to formal proposals none of them had dorsal intakes.

 

[Ogami musashi]

Yeah, that's what you want, a vortex going down the intake. :

Man...don't be sarcastic...if you don't understand my post..say it and ask me to be more precise.
I don't tell things out of my hat.


I said: "due to the sweeping of the upper region"...where did you see me saying vortex inside the inlet was a good thing..


Well..since you don't believe me...


http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810015531_1981015531.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070006754_2007006182.pdf


That should help you..

 

[chuck4]

This is boeing's concept for F-X, that is the successor of F-22, not the navy F/A-XX...hence it is an air dominance concept. This not because it has dorsal intakes that it means it is not good for maneuverability; Actually dorsal intakes have their share of aerodynamic advantages.

Compatibility with hard manuevering not being one of them.

The fundamental reason why dorsal intake is incompatible with hard maneuvering in a tailess aircraft is because of the human being in the cockpit. This prevents the plane from pulling hard negative G lest the pilot suffer cerebral hemorrhage. If the plane is meant to be optionally manned, and designed from the start to be able to pull hard negative Gs when there is no pilot, then there is no issue with dorsal intakes.


If a plane is tailless and pilotless, it can be made more or less aerodynamically symmetrical top and bottom, and be able to pull same hard Gs in either direction. If it is not completely aerodynamically symmetrical, and the intake must be either on the top of the bottom, then it can always hard maneuver in the other direction to avoid masking the intake while hauling the nose around.

 

[sferrin]

Well..since you don't believe me...


http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810015531_1981015531.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070006754_2007006182.pdf


That should help you..

Oh brother. The first article was from 1981. Can you think of any fighter programs since then -any- that have seriously proposed a dorsal inlet? Me either. The 2nd article you cite is for subsonic, low manueverability, aircraft. How that is applicable to the topic being discussed is apparently only known by you.

 

[Sundog]

Can you think of any fighter programs since then -any- that have seriously proposed a dorsal inlet?

The Gripen. But it was too risky for SAAB, so they went the conservative route.

 

[AeroFranz]

The fundamental reason why dorsal intake is incompatible with hard maneuvering in a tailess aircraft is because of the human being in the cockpit. This prevents the plane from pulling hard negative G lest the pilot suffer cerebral hemorrhage. If the plane is meant to be optionally manned, and designed from the start to be able to pull hard negative Gs when there is no pilot, then there is no issue with dorsal intakes.

not sure i understand...how does the intake layout or planform layout affect how many negative Gs a pilot can pull? a G is a G regardless of whether you are flying an aircraft or riding a donkey. I must be missing something...


We've talked about this before, but even without a pilot, it is doubtful that we will ever see a 12G UCAV. The penalty in structural weight required to withstands the loads eats into other more useful things, like payload and range. Not to mention that to sustain a 12G maneuver, you need some serious thrust, hence bigger engines, hence more fuel, hence more structure, and so on and so forth.

 

[chuck4]

A pilot can't handle lot of negative Gs. So pull high G for extreme maneuvering, the plane has to pull positive G. This means whenever the plane pulls high Gs, any dorsal intake would be on inside of the maneuver trace, and thus be on the wrong side, subject to being masked, or having its intake flow disturbed, by parts of the fuselage.

If a plane is pilotless, then it can be built to pull both high positive or negative G. In this case it doesn't matter whether its intake is dorsal or ventral. It can simply pull its G in the direction that would put the intake on the outside of the maneuver trace.

 

[sferrin]

Can you think of any fighter programs since then -any- that have seriously proposed a dorsal inlet?

The Gripen. But it was too risky for SAAB, so they went the conservative route.

So, like many others, when it came right down to it the dorsal intake didn't earn it's way onboard. Like I said.

 

[Ogami musashi]

... discussed is apparently only known by you.

I will answer you when you learn to speak properly to people....

 

[AeroFranz]

A pilot can't handle lot of negative Gs. So pull high G for extreme maneuvering, the plane has to pull positive G. This means whenever the plane pulls high Gs, any dorsal intake would be on inside of the maneuver trace, and thus be on the wrong side, subject to being masked, or having its intake flow disturbed, by parts of the fuselage.

If a plane is pilotless, then it can be built to pull both high positive or negative G. In this case it doesn't matter whether its intake is dorsal or ventral. It can simply pull its G in the direction that would put the intake on the outside of the maneuver trace.

Ok, i must have jumped in the conversation a bit late and was puzzled by the wording of your reply. The pilot G tolerance and inlet location stuff is all true. Whether you would want to make an axisymmetrical inlet location to give your UCAV good positive AND negative high G maneuvering is not as clear. As you well know, the Su-27 and F-16 inlets, use parts of the fuselage to realign the flow straight down the inlet for low fan face pressure distortion, so there is some use to being non-axisymmetrical. Then there is the question of masking your inlet to radars. Hard to do with something like a Pitot inlet. Assuming you were somehow able to give your engine good air at high positive and negative alphas, you would end up with a non-LO, higher-than-average structural fraction and thus either short legs or little payload. You'd have to find a CONOPS that justifies such a vehicle to make it worth it.

 

[Sundog]

Assuming you were somehow able to give your engine good air at high positive and negative alphas, you would end up with a non-LO, higher-than-average structural fraction and thus either short legs or little payload.

The YF-22, and YF-23, and F-22 all were designed with LO inlets with excellent performance at high positive and negative AOA and it has definitely proven out in F-22 flight testing.

 

[AeroFranz]

How many negative Gs are we talking about? We must be talking three or so max because that's usually the design load factor. Ok, maybe add the 1.5x engineering factor of safety (but you probably deformed the structure at this point) and you get to 4.5Gs. That's still FAR from 9Gs.
The F-22 and F-23 inlets are not axisymmetric and benefit from some overhang.



There is no free lunch in aircraft design. It's always a trade, and the thing is, it's always worse than you think it's going to be. Every time somebody talks about some great idea that comes for free you find out that almost invariably it affects some other area of design in such a way that the system as a whole is degraded.

 

[AAAdrone]

I'm pretty sure that the design load factor is indeed -3Gs of acceleration so I don't see how the F-22 could pull -9Gs. Back to the F-X, I'm with Matej in that It does seem that maneuverability may be less important with the design as the next generation appears to require the capability to use high off boresight SRAAMs, directed energy weapons like lasers and Masers as well as highly agile long range Dial-an-effect missiles like JDRADM. Really it does appear as if the next generation no longer requires your aircraft to engage the enemy by pointing it at them. You just fire missiles and leave.

 

[Sundog]

There won't be an airframe designed for -9g, manned or unmanned, because there isn't a need for it. It's like complaining that the F-22's inlets aren't good for Mach 12. It's a nonsensical argument. As long as the airframe is designed for 9gs manned, or maybe +12/14gs unmanned, you don't need the negative G rating. With the roll rates that can be achieved today, especially unmanned, you just roll and pull. Making such high negative g ratings would just add too much useless structural weight and therefore cost. It's a non starter.

 

[Stargazer]

Not to mention the high stress factors on the pilots, which caused fatal crashes by two of the three F-20 Tigershark prototypes when the pilots lost consciousness.

 

[chuck4]

A pilot can't handle lot of negative Gs. So pull high G for extreme maneuvering, the plane has to pull positive G. This means whenever the plane pulls high Gs, any dorsal intake would be on inside of the maneuver trace, and thus be on the wrong side, subject to being masked, or having its intake flow disturbed, by parts of the fuselage.

If a plane is pilotless, then it can be built to pull both high positive or negative G. In this case it doesn't matter whether its intake is dorsal or ventral. It can simply pull its G in the direction that would put the intake on the outside of the maneuver trace.

Ok, i must have jumped in the conversation a bit late and was puzzled by the wording of your reply. The pilot G tolerance and inlet location stuff is all true. Whether you would want to make an axisymmetrical inlet location to give your UCAV good positive AND negative high G maneuvering is not as clear. As you well know, the Su-27 and F-16 inlets, use parts of the fuselage to realign the flow straight down the inlet for low fan face pressure distortion, so there is some use to being non-axisymmetrical. Then there is the question of masking your inlet to radars. Hard to do with something like a Pitot inlet. Assuming you were somehow able to give your engine good air at high positive and negative alphas, you would end up with a non-LO, higher-than-average structural fraction and thus either short legs or little payload. You'd have to find a CONOPS that justifies such a vehicle to make it worth it.

I am not talking about an axial-symmetric intake, but just a conventional dorsal intake. With a manned aircraft, this would tend to restrict the aircraft's hard maneuverbility because the aircraft must pull positive G to suite the pilot and this would tend to degrade the performance of the intake. With an unmanned aircraft, a dorsal intake needn't have any effect on the aircraft's manenuverability since the aircraft could always pull high negative G, and in the process allow its ventral intake the full advantage of being totally exposed to undisturbed flow.

 

[flateric]

'old' FA-XX, but now in higher resolution

 

[fightingirish]

'old' FA-XX, but now in higher resolution

Please notice, that this picture shows one of the 'old' F/A-XX as a UCAV. It has no cockpit. Compare it with post #14 & #41.

 

[red admiral]

With an unmanned aircraft, a dorsal intake needn't have any effect on the aircraft's manenuverability since the aircraft could always pull high negative G, and in the process allow its ventral intake the full advantage of being totally exposed to undisturbed flow.

You have to bear in mind that it's not just the pilot which is limiting the manoeuvrability of the aircraft. A Nz limit graph will firstly have a section relating to lift limit before moving over towards the structural load limit. You'll find that the speed you can pull -9g or more is actually rather high with today's designs. This is because aerofoils tend to be optimised for lift in the upwards sense. For what you're proposing pulling a large negative Nz would require a much different aerofoil shape - and likely lead to really poor low speed (i.e. take-off and landing) performance.

I'm thinking it would be better to go with a ventral inlet and an aerofoil design that produces reasonable Cls when inverted. For cruise flight at high speed have the vehicle fly upside down so you essentially have a dorsal intake. You don't need much lift in high speed cruise so it may be possible without having a massive wing area. For heavy manoeuvering simply roll the aircraft and use it the "correct" way up. If you're having to do such manoeuvres the time for much signature management is probably over.

 

[flateric]

Please notice, that this picture shows one of the 'old' F/A-XX as a UCAV. It has no cockpit.

we deliver first&best!

 

[flateric]

...

 

[pedrospe]

great pictures ,thanks for posting them.




regards


pedro

 

[donnage99]

http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3ae9727358-67a4-4a83-bbc5-1e4f78c47fe1&plckScript=blogScript&plckElementId=blogDest

 

[shedofdread]

Interesting what Richard McCrary had to say re product development but it's only how motorsport has gone about things since... ooh I don't know - early last century.

There are times when I truly dispare of the way [some] defence companies carry on. Just because one has a massive potential budget, doesn't mean one has to spend it and just because there's no pressing need for that which you are working on doesn't mean you can drag your heels. Could this mean they're finally waking up to other ways of working? Hmmmm....

S
(NOT holding his breath)

 

[Ian33]

The springs to mind the exhaust taken from the hantom Ray for a classified ground testing project. Possible technology transfer from that to this tailess design?

 

[flateric]

from Lockheed Martin Aeronautical Systems 2012 calendar - via Clindits

 

[bobbymike]

from Lockheed Martin Aeronautical Systems 2012 calendar - via Clindits

Looks like a two engine version of the McDonnell Douglas/British Aerospace/Northrop JSF entry

http://frn.beedall.com/images/jast-md-ng-bae2.jpg

 

[SteveO]

from Lockheed Martin Aeronautical Systems 2012 calendar - via Clindits

Slinky! Guess LM liked the way the F-23 looked too ;D

 

[BDF]

That's probably the coolest looking notional 6th Gen fighter concept released so far. Hopefully we'll actually get to see something like that around 2030...

 

[AAAdrone]

from Lockheed Martin Aeronautical Systems 2012 calendar - via Clindits

Slinky! Guess LM liked the way the F-23 looked too ;D

I'm with Bobbymike in that it looks more like a rip-off of the McDonnell Douglass/Northrop/BAe JSF submission than Northrop's ATF submission.

In any case, the general consensus among these designs appear to be the deletion of as many control surfaces (especially tail surfaces) as possible as well as dorsal inlets for increased LO against ground radars. It's just that Northrop and MD were a little ahead of the curve back in the day.

I really am interested in whether these companies actually keep their idea of dorsal inlets considering the possibility that even the next generation of fighters may still need to perform hard maneuvers at alphas above 20 degrees.

It will also be interesting to see how well the F/A-XX submissions can land on a carrier with little to no tail but such capabilities are being developed and tested as we speak so there shouldn't be too much to worry about there.

 

[SteveO]

I'm with Bobbymike in that it looks more like a rip-off of the McDonnell Douglass/Northrop/BAe JSF submission than Northrop's ATF submission.

In any case, the general consensus among these designs appear to be the deletion of as many control surfaces (especially tail surfaces) as possible as well as dorsal inlets for increased LO against ground radars. It's just that Northrop and MD were a little ahead of the curve back in the day.

Don't forget the BAe Replica study too http://www.secretprojects.co.uk/forum/index.php/topic,1202.msg74535.html#msg74535

I guess it's a configuration those in the know like.

 

[LowObservable]

It looks a lot like the supersonic long-range strike model that the Skunk Works showed off in 2006.

I wouldn't read much into it. You'd get put up against a wall and shot at LMT today if you floated an after-JSF concept that looked realistic!

 

[BDF]

It looks a lot like the supersonic long-range strike model that the Skunk Works showed off in 2006.

I wouldn't read much into it. You'd get put up against a wall and shot at LMT today if you floated an after-JSF concept that looked realistic!

Yes you can definitely see influences of the LRS model in that design and I totally agree, it’s much like the early ATF concept drawings as none looked anything like the F-22 or YF-23. I think it does, however, illustrate some of the themes that you can expect to see in the next gen fighter such as the ventral intakes, nearly flat fuselage with all of the shaping on top instead of on the bottom (the fuselage canoe on the F-22 and F-35), no tail and shielded exhaust. However the one thing that sticks out to me is that it’s too small to be a hi-end air dominance fighter. Just a guestimate but it doesn’t look much larger than an F-16 or F-35 based on the size of the cockpit and the guy sitting in it. Still cool as hell though!