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

[sferrin]

These concepts are not necessarily what the company aims to propose (there are competitors listening) but they're indicative. The idea of showing something at USNL is to get the message across to customer people that you're thinking... and maybe the Navy Lt Cdr who stops to chat might be someone in the office that's also thinking about such things, and who knows where he'll be when he's a Capt.

Note that all the Boeing concepts have been absent vertical tails, finless and highly blended.

Not trying to be a smartass (honest) but absent vertical tails and finless? ??? What's the difference? If you don't have any vertical tails aren't you by definition "finless"?

 

[Sea Skimmer]

Wing mounted fins wouldn't be tail fins, though few aircraft have ever been built this way.

 

[chuck4]

Ventral fins like those on the F-14, 16, Su-27, etc are usually not considered to be tails.

 

[quellish]

It's generally accepted that a 6th Gen fighter will have a higher altitude and cruise point for a given mission set (think more Blackbird than Raptor; i.e. go fast/high and stay there). It will be interesting to see if DEW pans out enough to reduce the maneuverability requirements because if it does, it could mean a wing that is better tailored to high altitude and air speeds (deltas for instance). Couple that with the new ADVENT engine variants which has a higher compression ratio than current 5th gen engines and will be able to configure to a pure turbojet and you could have a design that should be able to cruise higher, perhaps much higher than the current 5th gen heavyweights. I could see this jet cruising another 10-15k higher and perhaps another 0.5 Mach higher. I'd imagine it'd infer similar kinetic advantages over a 5th gen as a 5th gen does over a 4th gen.

Strangely, this has been studied to death.
"Future Air Force Needs for Survivability"
http://www.nap.edu/catalog.php?record_id=11743

 

[BDF]

These concepts are not necessarily what the company aims to propose (there are competitors listening) but they're indicative. The idea of showing something at USNL is to get the message across to customer people that you're thinking... and maybe the Navy Lt Cdr who stops to chat might be someone in the office that's also thinking about such things, and who knows where he'll be when he's a Capt.

Note that all the Boeing concepts have been absent vertical tails, finless and highly blended.

Well it begs the question then, if these are similar to working designs then are these artist conceptions compatible with the current design requirements regarding signature? The reason I ask is that my understanding is that both the F-X and F/A-XX will be geared towards broadband all aspect VLO (even ELO) to all known threat frequencies, including VHF. If that's the case then the only design shown so far that meets that is Boeing's F-X concept.


That F-X design has design features as what that is publicly known to be effective in those frequencies; smooth nearly flat bottom, dorsal intakes and other vertical protrusions located inside the outer perimeter line and no vertical stabs. The LM F- X and this new Boeing FA-XX designs don't appear to have this.
Also none of these designs appear to come close to carrying enough fuel for the 1000-1500nm combat radius that has been thrown around.

 

[TaiidanTomcat]

who knows where he'll be when he's a Capt.

Probably being called a Boeing shill?

 

[sublight_]

The curie point problem is still there for a VLO aircraft.

The Zinc oxide suddenly becomes highly reflective at higher temperatures?

 

[kcran567]

How are they going to get good high AOA control in yaw without any vertical stabilizers? I know that there are patents for nose mounted vortex control "jets" and maybe fluidic thrust vectoring. RE: fuel and range, it would seem that this aircraft would have to be much bigger than the f-22? Maybe larger than a j-20? any way to increase range without vastly increase in airframe size? Is the need to maneuver completely outdated at this point?

 

[pathology_doc]

Regardless of what form it takes - if it can't be sold to large numbers of overseas customers to defray the costs, is it ever going to exist? It's all very well to want the best of everything with all the right buzzwords hung off the name and all the right weapons packed inside a radar-invisible blended box, but sometimes you need Starfighters and A-4's as much as (if not more than) F-106's and B-58's. If the F-22 and the F-35 are the high-low mix of the current generation, then the low end is still way, way too high.


Just food for thought.

 

[quellish]

How are they going to get good high AOA control in yaw without any vertical stabilizers? I know that there are patents for nose mounted vortex control "jets" and maybe fluidic thrust vectoring. RE: fuel and range, it would seem that this aircraft would have to be much bigger than the f-22? Maybe larger than a j-20? any way to increase range without vastly increase in airframe size? Is the need to maneuver completely outdated at this point?

http://en.wikipedia.org/wiki/Rockwell-MBB_X-31

 

[Sundog]

How are they going to get good high AOA control in yaw without any vertical stabilizers? I know that there are patents for nose mounted vortex control "jets" and maybe fluidic thrust vectoring. RE: fuel and range, it would seem that this aircraft would have to be much bigger than the f-22? Maybe larger than a j-20? any way to increase range without vastly increase in airframe size? Is the need to maneuver completely outdated at this point?

Canards don't have a problem controlling aircraft in yaw at high AOA and TV works as well. See Quellish's link above regarding the X-31. You may wish to also check out the X-36.

 

[lantinian]

That's a nice PDF link.... Already reading the summary and could help posting this quote

"Recommendation 2: Before choosing a design point on the speed-stealth performance curve, the Air Force needs to conduct rigorous analyses and trade-off studies as a basis for that decision."

So whether speed helps and how fast should the next US aircraft platform fly is not exactly clear even to USAF as they have not yet studied the problem enough

 

[lantinian]

Is the need to maneuver completely outdated at this point?

No. It's not the need to maneuver that's becoming outdated, it's the combat speed at which that keeps increasing. Look at the optimum maneuvering speed from WWI till now for each fighter generation.

 

[quellish]

That's a nice PDF link.... Already reading the summary and could help posting this quote

"Recommendation 2: Before choosing a design point on the speed-stealth performance curve, the Air Force needs to conduct rigorous analyses and trade-off studies as a basis for that decision."

So whether speed helps and how fast should the next US aircraft platform fly is not exactly clear even to USAF as they have not yet studied the problem enough

USAF, contractors, and others have studied it quite a bit. The problem here though is that different parties have different ideas of what a realistic signature is.
Speed helps, just as it did with OXCART, even if the threat eclipsed the platform before it was operational. With modern aircraft the signatures are *much* lower and the requirements far more complex. It's easier to lose the edge that VLO gives you as speed increases. Let's say you are -50dbsm at M1.2 and 52k. At M2.5 and 52k you may be -20dbsm because of aerothermal heating effects on coatings, etc, which negates most of the advantages the speed and altitude give you.

 

[Triton]

Probably being called a Boeing shill?

Seriously? A rather nasty comment. I don't need to remind you that Boeing is the successor of MCAIR and the owner of the Phantom Works. Why wouldn't members of the service think it was the latest thinking out of St. Louis and think of the service's long history with both McDonnell and Douglas?

 

[GTX]

Probably being called a Boeing shill?

Seriously? A rather nasty comment. I don't need to remind you that Boeing is the successor of MCAIR and the owner of the Phantom Works. Why wouldn't members of the service think it was the latest thinking out of St. Louis and think of the service's long history with both McDonnell and Douglas?

He was being sarcastic I think - a reference to the constant belittling of those who might support the Lockheed F-35...

 

[Triton]

I presume a sarcastic comment directed at LowObservable.

 

[lantinian]

It's easier to lose the edge that VLO gives you as speed increases. Let's say you are -50dbsm at M1.2 and 52k. At M2.5 and 52k you may be -20dbsm because of aerothermal heating effects on coatings, etc, which negates most of the advantages the speed and altitude give you.

No argument here, but where is the balance between the two. What is the maximum speed that can be achieved without significant signature degradation. I think that's where "more studies are needed" part comes in.

 

[quellish]

It's easier to lose the edge that VLO gives you as speed increases. Let's say you are -50dbsm at M1.2 and 52k. At M2.5 and 52k you may be -20dbsm because of aerothermal heating effects on coatings, etc, which negates most of the advantages the speed and altitude give you.

No argument here, but where is the balance between the two. What is the maximum speed that can be achieved without significant signature degradation. I think that's where "more studies are needed" part comes in.

There are plenty of studies, they all reach different conclusions. Why? Mostly because each study has different data for what levels of signature reduction are possible in the near term.
Nonetheless, many of these studies have converged at more or less the same points largely because of how speed drives configuration, and how that (can) conflict with observables requirements.

 

[mkellytx]

It's generally accepted that a 6th Gen fighter will have a higher altitude and cruise point for a given mission set (think more Blackbird than Raptor; i.e. go fast/high and stay there). It will be interesting to see if DEW pans out enough to reduce the maneuverability requirements because if it does, it could mean a wing that is better tailored to high altitude and air speeds (deltas for instance). Couple that with the new ADVENT engine variants which has a higher compression ratio than current 5th gen engines and will be able to configure to a pure turbojet and you could have a design that should be able to cruise higher, perhaps much higher than the current 5th gen heavyweights. I could see this jet cruising another 10-15k higher and perhaps another 0.5 Mach higher. I'd imagine it'd infer similar kinetic advantages over a 5th gen as a 5th gen does over a 4th gen.


It's also conceivable that with the advances in materials and manufacturing technologies there could be significant weight savings which could of course translate not only higher altitude/Mach but could also allow for higher available G at any given altitude/Mach point. That's pretty important feature since being able to rapidly change your vector (cranking) is important in BVR tactics. Personally as cool as these concept drawings are, I don't think they anything like what these respective design houses are working on.

Not to dump cold water all over this idea, another 10-15K above the Raptor pushes the A/C past human physiological limits. The Raptor is already bumping up against the Armstrong limit at 62K, so unless you want the crew wearing pressure suits and pre-breathing O2 60-62K is the ceiling.

 

[TaiidanTomcat]

Not to dump cold water all over this idea, another 10-15K above the Raptor pushes the A/C past human physiological limits. The Raptor is already bumping up against the Armstrong limit at 62K, so unless you want the crew wearing pressure suits and pre-breathing O2 60-62K is the ceiling.

It has not been pleasant on the pilots either.

 

[sferrin]

It's generally accepted that a 6th Gen fighter will have a higher altitude and cruise point for a given mission set (think more Blackbird than Raptor; i.e. go fast/high and stay there). It will be interesting to see if DEW pans out enough to reduce the maneuverability requirements because if it does, it could mean a wing that is better tailored to high altitude and air speeds (deltas for instance). Couple that with the new ADVENT engine variants which has a higher compression ratio than current 5th gen engines and will be able to configure to a pure turbojet and you could have a design that should be able to cruise higher, perhaps much higher than the current 5th gen heavyweights. I could see this jet cruising another 10-15k higher and perhaps another 0.5 Mach higher. I'd imagine it'd infer similar kinetic advantages over a 5th gen as a 5th gen does over a 4th gen.


It's also conceivable that with the advances in materials and manufacturing technologies there could be significant weight savings which could of course translate not only higher altitude/Mach but could also allow for higher available G at any given altitude/Mach point. That's pretty important feature since being able to rapidly change your vector (cranking) is important in BVR tactics. Personally as cool as these concept drawings are, I don't think they anything like what these respective design houses are working on.

Not to dump cold water all over this idea, another 10-15K above the Raptor pushes the A/C past human physiological limits. The Raptor is already bumping up against the Armstrong limit at 62K, so unless you want the crew wearing pressure suits and pre-breathing O2 60-62K is the ceiling.

Not to be a smartass, but the air must be different over Russia as they seem to have operated Mig-25s and -31s routinely at the higher altitudes. If one were really worried about it one could do like they did with the XB-70, B-58, and had planned to do with the XF-108, or even further and do like the F-111 and B-1A. Not saying these are ideal solutions, just saying that where there's a will there's a way.

 

[mkellytx]

Not to be a smartass, but the air must be different over Russia as they seem to have operated Mig-25s and -31s routinely at the higher altitudes. If one were really worried about it one could do like they did with the XB-70, B-58, and had planned to do with the XF-108, or even further and do like the F-111 and B-1A. Not saying these are ideal solutions, just saying that where there's a will there's a way.

Scott,


Just looking at this from an US aircrew perspective. No operations above 50K with current life support equipment (and depending on the platform, above 42K you have the mask up pressure breathing in 100% O2), Raptors get to 60K b/c the life support equipment acts as a partial pressure suit(so I'm told). When I was in the business, many moons ago, I worked with U-2 pilots who did operate well north of 50K and 60K in full pressure suits, pre-breathing pure O2 to avoid the bends. I think the Russians wear at least partial pressure suits on the -25 and -31 up really high. The problem is above about 62K is that blood boils. Buying hundreds of A/C requiring very expensive life support ensembles and pre-breathing pure O2 to get rid of the N2 in the blood would be more trouble than its worth.


The XB-70, XF-108 and B-58 required partial pressure suits for the really high fast stuff. The SR-71 and U-2 did to, the B-1A IIRC had a ceiling of 60K and could be survivable if depressurized in theory.




Cheers

 

[Magoodotcom]

who knows where he'll be when he's a Capt.

Probably being called a Boeing shill?

 

[kcran567]

How are they going to get good high AOA control in yaw without any vertical stabilizers? I know that there are patents for nose mounted vortex control "jets" and maybe fluidic thrust vectoring. RE: fuel and range, it would seem that this aircraft would have to be much bigger than the f-22? Maybe larger than a j-20? any way to increase range without vastly increase in airframe size? Is the need to maneuver completely outdated at this point?

Canards don't have a problem controlling aircraft in yaw at high AOA and TV works as well. See Quellish's link above regarding the X-31. You may wish to also check out the X-36.

I'm very familiar with the x-31 and 36. What I was getting at was are we even sure that the next fighter will be thrust vectored at this point? I was sure that the f-35 was going to get a 3-d nozzle and was disappointed when it did not get one. We all know the argument for and against thrust vectoring and obviously the f-35 is without it because it was deemed unnecessary. How much time is the next fighter going to spend in post stall maneuvers? I also mentioned the vortex control nose mounted devices and fluidic vectoring (like the x-36 has?) and are those possibilities on the next fighter. And will the next fighter be larger than the J-20, it seems to be probable in order to have the necessary range and loiter capability to surpass current fighter designs.
Does a joint USA/Japan project sound reasonable considering the astronomical costs involved?

 

[Dragon029]

I had thought the F-35 didn't have thrust vectoring due to the extra weight and complexity that the B model would have moving around on it's exhaust.

Obviously the X-32 had thrust vectoring, but it's system was less dependent on such large, individual thrust posts.

 

[lantinian]

What I was getting at was are we even sure that the next fighter will be thrust vectored at this point? I was sure that the f-35 was going to get a 3-d nozzle and was disappointed when it did not get one. We all know the argument for and against thrust vectoring and obviously the f-35 is without it because it was deemed unnecessary. How much time is the next fighter going to spend in post stall maneuvers?

Trust vectoring was originally developed to enhance combat maneuverability and provide STOL performance since those qualities were thought to increase the overall system survivability at the 80s. The current thinking I believe is that survivability is better preserved by keeping the fighter energy high and letting the missiles do the turning. This also keeps the fighter in level flight, preserving its lowest signature profile to the most likely enemy sensor locations. Not having trust vectoring also saved weight which was important to meeting other range and performance requirements.


Trust vectoring still has a bright future as its seen replacing altogether some of the traditional aerodynamic surfaces, because it allows for aircraft control over much infinite speed, height and AoA envelope. Reducing number of aircraft flight control surfaces will have added benefits to range and reduced signature as well.


Trust vectoring however, as implemented in the F-22 was never intended to replace a flight control surface and thus simplify the design of the aircraft. The reason is pretty simple: Reliability. For TVC to work, both the engine and the TVC system need to work. At this time neither is more reliable than a simple hydraulic flight control. For mechanical TVC, this is likely to remain so, therefore its is highly unlikely than the next fighter will have TVC as in the F-22.


On a side note, the way the USAF used the F-22 in mock combat in Red Flag proved Northrop assessment than a TVC in not required for the ATF mission and represents unneeded weight and complexity, hence the lack of TVC on the YF-23 which made it much harder to be engaged in the rear quarter.


It is therefore my understanding that only a non mechanical TVC (as the fluidic one in X-36) has a chance of being a feature of the F-X provided it brings much more side benefits and fewer drawback than the F-22 one.

 

[Sundog]

Just an FYI, IIRC, the X-36 only vectored it's thrust in yaw, not pitch.

 

[lantinian]

That's a great point. It proves that Boeing was only interested in studying how suitable is TVC as replacement for the vertical tail, not any fancy post-stal maneuvers.

 

[BDF]

DARPA's Air Dominance Initiative


The Pentagon's Defense Advanced Research Projects Agency (DARPA) is studying next-generation fighter concepts under a new air dominance initiative that should yield results for next year's budget cycle.
DARPA director Arati Prabhakar says that the air dominance study grew out of conversations she had with Pentagon procurement chief Frank Kendall when she took the helm at DARPA last year. "Out of those conversations came the notion of taking a look at air dominance and asking the question about how we could create this generational shift and how we could extend our air superiority capability," she says. However, Prabhakar adds the caveat that "there really isn't going to be a silver bullet technology that, for example, extends air superiority into the next three or four decades."


But the Pentagon believes that it must begin studying technologies to take on advanced threats because future threats will be much more dangerous that the enemies the USA has faced since the end of the Cold War. "Frank Kendall, I think, also had a strong view that, first, that it's very important for us to create this generational shift in capability recognizing that the threats we are going to face in the future are likely to be much more sophisticated than what we have seen in the last decade," Prabhakar says.

Prabhakar says that DARPA has "very deliberately" chosen a "systems approach" to the problem. "This is not a question about what does the next aircraft look like, this is a question about what are all the capabilities that it will take, layered together, in order to really comprehensively extend air superiority," she says.
DARPA is conducting the study in conjunction with the US Air Force and the US Navy. There are eight DARPA programme managers matched with USAF and USN experts working on next generation technologies for the project. Those technology areas span networks and communications, control of the electromagnetic spectrum, sensing across the electromagnetic spectrum, manned and unmanned teaming, and the role of space-based assets. "It been a very high-energy effort over the last few months," Prabhakar says.
Preliminary results from the study could influence further developments as early as the fiscal year 2015 budget process."At this point, we're just a few months into a study, what I hope will come out of this will be some initiatives for the next budget cycle," Prabhakar says.



http://www.flightglobal.com/blogs/the-dewline/

 

[quellish]

That's a great point. It proves that Boeing was only interested in studying how suitable is TVC as replacement for the vertical tail, not any fancy post-stal maneuvers.

Post-stall maneuver is not something the customers are interested in.

 

[Deino]

http://www.youtube.com/watch?feature=player_embedded&v=GDLas_2Qy-E

Deino

 

[Sundog]

If any of you would like to print your 3D planes, go to shapeways. I make parts for model kits using this technology. But they have to be solid models, not just a 3D mesh model.

We also use this technology at work for prototyping, before we invest in molds/dies. Though that isn't through shapeways as they can't print parts large enough; We do it through another company that has printers similar to, if not the same, as the ones shown in the Boeing video.

 

[kcran567]

Just speculating, but that printed model shows some detail, but it doesn't seem to show any flaperons or leading edge flaps. Maybe it uses aeroelastic tailored/wing warping like the NASA f-18 research aircraft.


I'm expecting better range, altitude, higher speed, and loiter ability than today's 5th generation aircraft.

 

[flateric]

LM 6G paper study under ESAVE program

has two equal volume weapon bays one behind other a-la T-50

 

[helmutkohl]

Is that supposed to be the bays?

they look really narrow.

Deino

 

[lantinian]

has two equal volume weapon bays one behind other a-la T-50

forgot to mention that is has the YF-23 rear fuselage and no mechanical vectoring nozzles.. oh the irony!

 

[Stargazer]

I could be wrong, but the aircraft depicted looks extremely flat... and each of the wings highly disproportionate from the other.

Perhaps the image was distorted? Here is the same image reduced in width to 75% of the original and 50% of the original. Though the latter is obviously exaggerated, it does bring the wings to more of a similar size. Apart from the wings, the 75% version looks pretty good overall. Just my two cents.

 

[Dragon029]

It must just be rendered in orthographic rather than perspective (hence, the dimensions remain constant regardless of distance from the viewer).

 

[saintkatanalegacy]

Yip, it's orthographic. So I guess they're going for yaw thrust vectoring.