Chinese Carrier Fighter Project !

[B777LR]

THose boxed wings, do they work by simply sorta cutting the wing in halfways between the tip and root, and placing that bit you cut off low down?

[Planeman]

Afraid it's far more complex than that. For a start there are several types of "joined wing" configurations which offer different advantages.

These ones have are unique in that the forward wing is all-moving much like having a giant canard. This eliminates having control surfaces as part of the wing (ie. the wing is the control surface) and this saves weight and allows for a 100% composite wing. The all-moving leading wing can remain in positive lift even when the aircraft is at high angles of attack, because it can adjust its incidence to match the oncoming airflow.

The rear wing is forward swept. The main advantage is that this results in very slow stall speeds especially at high angles of attack. There are further control surfaces behind the rear wing (used mainly for trim and at high AOA), and of course the outward canted twin stablisers. Add to that thrust vectoring control and you have an aircraft wing high lift, very slow take-off land speeds and exceptional agility. Transonic drag may suffer. There are ways to reduce form drag but I'll skip those.

No aircraft has ever been flown in this configuration with an all-moving forward joined wing.

[kitflubber]

Planeman,

Was talking with Greg (Chtulhu77) who mentioned that chin intakes are not popular on carriers...

I whipped up a drawing with cabin and intakes reversed. The plane is slightly longer.  I believe there are aerodynamic tradeoffs with intakes up there as well.

[Planeman]

Above fuselage intakes have problems at high angles of attack because they become masked by the forward fuselage. That pretty much rules them out here. Shame as your redesign looks rather nice.

The thing about chin intakes being unpopular on carriers is a bit like the story that single engine fighters are unpopular, there are loads of exceptions. In fact the successful and popular A-7 & F-8 Crusader had both those features. And the X-32, although it didn't win. But the chin intake wasn't the reason.

There's nothing wrong with having a chin intake. At any rate it'd be a crap carrirer fighter anyway because there's no practical way of giving it folding wings so I guess it's a land fighter.  

[kitflubber]

Planeman,

Here is a look with the lower fuselage strakes 'notched' or blended/removed for a section to allow freeflow intake at high AOA.




As for chin intakes, I really don't know more than Greg said, though I did work with a Navy vet who referred to Corsairs (or was it that Chance-Vought thing?) as 'Chief-eaters.' Don't know if he was just reporting gallows humor from the flight deck, or real everday risk.

[cthulhu77]

From a pilot's standpoint, I think the only big disadvantage to the intake on top would be visibility...is there a way to move them/split the intake to the sides?
 Anyone out there have a F-22 1/32nd scale they want to trade for something? I'd like to build this sucker.

[kitflubber]

Cthulhu77,

I could do one with side intakes -- Planeman has already done a nonstealth version like this.

[kitflubber]

Planeman, I wonder if the 'choked strake' version I did would not benefit from canards to add maneuvarability and direct intake flow?

[kitflubber]

Another with better visibility for pilot:

[kitflubber]

Wing folding ideas... it might not be a good dea for the forward wing to have hinge midway. so maybe it could detach from the outer pylon anf flip up.

[cthulhu77]

That's gonna be a real bitch to build, but I like it !

[Planeman]

I love the creativity, very analytical and problem solving also. I think the intake concerns are a bit of a red herring, it's a carrier myth just like single engine carrier jets. What's the difference between a single belly intake and twin belly intakes as per the Su-27? Or the intake on the X-32?

There's a few other things about my design that I haven't really explained that might throw new challenges at your redisgn process. Stealth is a major part of its shaping. The slab sided/side intake option, whilst tempting would be terrible for stealth.


Canards. Have thought about those before, maybe as a way of allowing the forward wing to be non-moving and yet still be good at extreme high AOA approaches (slow speed). Here's an earlier canard design from my single engine UCAV project (non-stealth BTW).

But with the all-moving forward wing there's really no need for canards.


Re the wing fold. Nice ideas, but would add weight and probably compromise stealth. One of the reasons for going for joined wings is that they can be light weight because they have structural strength (being connected) and almost entirely composites (radar transparent in some cases). The wing fold mechanism would have to be metal(?) and that would complicate the internal structure of the wing(s) a lot. There's already some metal in the rear wing for the flaperon articulation, but this is compounding that problem. But if we did have to go for wing fold, your bottom illustration is by far the best.


EDIT, actually, designing a stealthy wing fold is the sort of challenge I like. It could use marsking by the wingtip structure.  

[cthulhu77]

The dual intake is for spin control...with one, you run the risk of flameout too much. ( a real problem with early carrier aircraft)

  I like the idea of stealthy folding wings...since we are talking future-time, we could speculate on the properties of composite wing folding structures/joints?

[Planeman]

Aside from COLAB and also the inevitable Dornier Rutenflugel, a stylistic influence influence was the latest Chinese concept models that are doing the airshow rounds:



The joined wing design needs to be deeper, partly to allow for a large weapons bay, and partly to increase verticle seperation if the wings.

[kitflubber]

Planeman,

What is marsking?