General F/A-XX thread

[sprstdlyscottsmn]

Guys, these are not mutually exclusive. Look at the dates. In 2012, Spaz posted about testing done in 2010 where sub 140kt values were achieved. what disconnectedradical is pointing out is that AFTER those posts were made, in the 2012-2013 timeframe, a decision was made to go from 30 degree TEF to 15 degree TEF to improve handling. This raised the approach speed to 147.9 knots at the maximum weight of 46klb.

[ricnunes]

Guys, these are not mutually exclusive. Look at the dates. In 2012, Spaz posted about testing done in 2010 where sub 140kt values were achieved. what disconnectedradical is pointing out is that AFTER those posts were made, in the 2012-2013 timeframe, a decision was made to go from 30 degree TEF to 15 degree TEF to improve handling. This raised the approach speed to 147.9 knots at the maximum weight of 46klb.

Exactly!
It was only a change in the approach profile (shallower approach) which obviously lead to the increase on approach speed. Seems obvious that a change in approach profiles leads to an aproach speed increase.

Moreover, 147.9 knots at the maximum weight of 46klb equals to a carrier bring back capability of a full internal weapons loadout (2x 2000 lb bombs + 2 x AMRAAMs) plus 33% (or 1/3) of fuel. Not bad at all, in my book!

So no, this change in approach profile isn't the reason why the US Navy isn't procuring the F-35C in numbers right now and definitely doesn't mean that the F-35C doesn't meet it's bring back capability. (the reason of this "discussion" in the first place)

[sprstdlyscottsmn]

I would not say it is a shallower approach, just a faster approach with less flap deflection. This would allow Magic Carpet to be more responsive as it works my altering the flap settings.

[disconnectedradical]

It was only a change in the approach profile (shallower approach) which obviously lead to the increase on approach speed. Seems obvious that a change in approach profiles leads to an aproach speed increase.

???
There was no mention of a shallower approach. The reason for the increased carrier landing speed is the TEF position changed due to handling quality concerns.

The high landing speed does affect the bringback, it’s simple physics. This isn’t to say that it’s a severe issue or it makes the F-35C a bad aircraft, and the landing characteristics is likely still acceptable for USN. But I’m pointing out potential areas that I imagine for F/A-XX, they may want more. Note that I mentioned Super Hornet limitations too. The F/A-XX is meant to be superior to both.

Frankly, I don’t know why you are so aggressive with this and instantly assume I made something up, especially considering that the 2023 SAR document has been posted here before a few times.

[ricnunes]

I would not say it is a shallower approach, just a faster approach with less flap deflection. This would allow Magic Carpet to be more responsive as it works my altering the flap settings.

Yes, perhaps this doesn't necessarily translate into a shallower approach however a lesser flap deflection (15 degree instead of 30 degree) will obviously increase the aircraft's stall speed which obviously and inevitably will increase the aircraft's approach speed.

[sprstdlyscottsmn]

Right, that is the reason for the change from sub 140 to "147.9" at the same weight.

[ricnunes]

The high landing speed does affect the bringback, it’s simple physics. This isn’t to say that it’s a severe issue or it makes the F-35C a bad aircraft, and the landing characteristics is likely still acceptable for USN.

You clearly said that the reason why the US Navy wasn't procuring more F-35C's was probably because of this "increase in approach speed" and therefore that the F-35C failed it's approach speed requirements which is false. At least admit this.
The F-35C didn't fail any approach speed requirements but instead is was the requirements that changed: 30 degree flap deflection to 15 degrees.

But I’m pointing out potential areas that I imagine for F/A-XX, they may want more. Note that I mentioned Super Hornet limitations too. The F/A-XX is meant to be superior to both.

If you think that the F/A-XX - if it ever sees the light of day (I do really hope so but...) - won't have any or significant carrier landing approach limitations then I have all the bridges in North America to sell you! I hope I'm not being "too aggressive" here

Frankly, I don’t know why you are so aggressive with this and instantly assume I made something up, especially considering that the 2023 SAR document has been posted here before a few times.

Because of what I mentioned in my first paragraph of this post.

[sprstdlyscottsmn]

The F-35C didn't fail any approach speed requirements but instead is was the requirements that changed: 30 degree flap deflection to 15 degrees.

I disagree with this assessment. The approach speed requirement is failed, but it was knowingly failed as a way to improve safety and handling. The handling characteristics on approach were deemed more critical than an 8 knot increase in speed. Clearly the wires can handle the stress because the F-35C is out on combat cruises now, it is operational.

[ricnunes]

The F-35C didn't fail any approach speed requirements but instead is was the requirements that changed: 30 degree flap deflection to 15 degrees.

I disagree with this assessment. The approach speed requirement is failed, but it was knowingly failed as a way to improve safety and handling. The handling characteristics on approach were deemed more critical than an 8 knot increase in speed. Clearly the wires can handle the stress because the F-35C is out on combat cruises now, it is operational.

From what I see and read and this can be read in the links and quotes mentioned on Spaz's post (which I previously posted), the F-35 met the requirements (including carrier approach speed and landing) with distinction during carrier trials. Granted that this happened with 30 degree flap deflection. Now and apparently the landing requirements are with a 15 degree flap deflection, so I fail to see this as a requirement failure.

[gtg947h]

I'm really curious what these handling issues were at flaps 30... perhaps the DLC (or whatever that function is called) didn't work well enough at that setting?

[disconnectedradical]

You clearly said that the reason why the US Navy wasn't procuring more F-35C's was probably because of this "increase in approach speed" and therefore that the F-35C failed it's approach speed requirements which is false. At least admit this.
The F-35C didn't fail any approach speed requirements but instead is was the requirements that changed: 30 degree flap deflection to 15 degrees.

USN's current procurement rate of the F-35C is not very high. Perhaps that's because they want to wait for Block 4, or maybe they're not satisfied with the higher landing speed, who knows. I'm presenting it as a possibility, not a certainty, but regardless the USN F-35C procurement rate has been sluggish. That being said, I do expect that all 340 F-35C between the USN and USMC will be procured, since it's a fairly small number in the first place. And none of this is to say that the F-35C is even a bad aircraft, in fact even with Block 3F it's the overall most capable strike fighter the USN has. But that doesn't mean it's not without some limitations, or there may be areas that they want more performance. Hence F/A-XX is likely to address these, as well as Super Hornet limitations.

From what I see and read and this can be read in the links and quotes mentioned on Spaz's post (which I previously posted), the F-35 met the requirements (including carrier approach speed and landing) with distinction during carrier trials. Granted that this happened with 30 degree flap deflection. Now and apparently the landing requirements are with a 15 degree flap deflection, so I fail to see this as a requirement failure.

That's NOT how requirements flow work, the USN has a requirement, or KPP, for carrier landing speed, and that's a system level requirement and it's up to the F-35C contractor to find out how to achieve that, through flight control laws, TEF scheduling, etc. So things like the TEF scheduling is NOT stipulated by USN, that's a lower level specification by Lockheed Martin that's derived from the carrier landing speed, not the other way around. The SAR even said that 30 degree TEF position wasn't used because of handling quality concerns. If the 30 degree TEF position could lower the landing speed but was deemed unsafe or have unsatisfactory handling, then what's the point? This is a failed requirement, period. That's not to say this makes the aircraft a failure or even bad, even successful designs have failed requirements, but you can't just sugarcoat this.

[Corsair1963]

With the release of photographs of two Chinese 6th Generation Stealth Fighters on a single day.


It makes you wonder. If, the US Government will now follow suit with the F/A-XX? (Naval NGAD)

[laos]

What has been revealed are not even 5th generation fighter prototypes, let alone 6th generation.
A 5th generation aircraft is not just a shape. It's also 5th generation engines, DAS, stealth, GaN radar and many more.

In this demonstrator, 3 WS-10 engines were probably inserted, because the Chinese don't have enough powerful and modern engines. This makes the whole fuselage filled with 3 air channels and no armament chamber. So it can't carry armaments inside the fuselage. On top of that, it has small vertical control surfaces, so it is very far from the stealth F-35. It has no DAS.

In my opinion it's simply a demonstrator to work on fly-by-wire systems in a flying wing configuration. Nothing more.

[mixelflick]

What has been revealed are not even 5th generation fighter prototypes, let alone 6th generation.
A 5th generation aircraft is not just a shape. It's also 5th generation engines, DAS, stealth, GaN radar and many more.

In this demonstrator, 3 WS-10 engines were probably inserted, because the Chinese don't have enough powerful and modern engines. This makes the whole fuselage filled with 3 air channels and no armament chamber. So it can't carry armaments inside the fuselage. On top of that, it has small vertical control surfaces, so it is very far from the stealth F-35. It has no DAS.

In my opinion it's simply a demonstrator to work on fly-by-wire systems in a flying wing configuration. Nothing more.

I think you're 100% right about why it needs 3 engines.

Allegedly, the new J-20's rolling off production lines are fitted with the mature, WS-15 engine. Provided that's the engine used here, the mature engine goal was to reach 36,000lbs in max afterburner (possibly as much as 40,000lbs). In military power, the goal was approximately 24,000lbs. That I'm guessing, is the issue..

Even pumping out a monster 28,000lbs in military power, the F-35 still doesn't achieve real super-cruise. This thing looks to be easily double the F-35's gross weight, so 2 engines doesn't get them there. When super-cruise is necessary, the 3rd engine does.

Yes, I'm aware the F-35 is also hamstrung by it's thick fuselage, area/rule drag being a factor. But even assuming the WS-15 hit its metrics and is in service, they likely need 3 to give it the "oomph" it needs.

[weasel1962]

PLA doesn't normally issue serials to demonstrators. Using J-20 as a gauge, it had previously used 4 digit serials for early prototypes before transitioning to the 5 digit serials. 36011 is still a first prototype (3rd and 5th digit basis) with 361 mirroring early J-31 prototype (which used 31001), consistent with PLAAF serial practice. FC-31/J-31 is an example how the early prototypes never went into production (and had to be revived as the J-35).

Prior to production, substantial number of prototypes tend to be built so its too early to use this aircraft as a definition for how the production variant would be. There was substantial redesigns for the J-20 from 1st serial to final production sequence. They won't put all the bells and whistles but this aircraft is far further in development than J-20 which suggest a shorter development cycle.

Only when there are a few more units, can anyone then suggest how the production units will look like or even whether this will enter production. I'd wait and see.