J-20 5th Gen Fighter Thread V

plawolf · Nov 15, 2015

A naval a J20 is going to need some significant design changes.

The folding wings are easy, even the airframe strengthing isn't that troublesome. What will be the biggest challenge in my view will be the landing gears, specifically, the placement.

Currently, the J20's landing gear is fairly forwards, and stubby.

For a carrier fighter, they will probably want to move the MLGs further aft, and/or extend the MLG to give the plane more alpha on approach to a trap.

The may also need to shrink, or maybe delete the vental tailfins as well to limit the chances of tail strike upon landing. If they do that, it will significantly change the CoG of the J20 as well as its aerodynamics.

That will elevate the J20's tail when she is in the ground to give her a crouching, or head stooped ready to pounce look, which should make quite a striking frontal shot.

kurutoga · Nov 16, 2015

SinoSoldier said:
Huitong is saying that the PLANAF has selected a naval variant of the J-20 over the FC-31.

How was Huitong's track record in this type of predictions?

Blitzo · Nov 16, 2015

kurutoga said:
How was Huitong's track record in this type of predictions?

He tends to be an aggregate of rumours from the various Chinese language boards... his track record is fairly decent and in some cases having an updated rumour on his site is a key milestone for considering the validity of a rumour.

That said, often these claims are acknowledged clearly as rumours, as is this one.

The important thing is to realize that everyone can make mistakes when trying to make these kind of projections, and that new information might turn previous understandings and consensus of a rumour upside down.

newguy02 · Nov 16, 2015

SinoSoldier said:
Or PLAAF.

I would think that since the J-20 is eventually going into PLAAF service that they would not choose the FC-31.

Alvaritus · Nov 16, 2015

newguy02 said:
I would think that since the J-20 is eventually going into PLAAF service that they would not choose the FC-31.

They could go for a HI/low strategy (like F15/F16 in the USAF) .... its cheaper than having an all J-20 airforce but still very capable into the next decades...

Richard Santos · Nov 16, 2015

To make j-20 into a naval fighter will likely involve major changes to the shape and size of the wing and possibly canard, in addition to strengthening the airframe overall for the stresses of carrier takeoff and landings. The near delta shape of the j-20 wings are excellent for transonic and supersonic drag, but poor for low approach speed and handling. To improve carrier approach characteristics would likely involve giving j-20 wholly new wings with substantially reduced leading edge sweep, increased span, and increased area, along with larger high lift devices on the trailing edge, and possibly leading edge as well.

The main landing gear wheels would also likely be moved further aft relative to the aircraft's center of gravity to improve the aircraft's tendency to pitch down during wheel touch down. I wouldn't be surprised if it gains f/a-18 style kneeling main landing gear legs to help absorb landing shocks and move the wheels further aft without relocating wheel well.

I am going to guess the front landing gear leg would be relocated to the front of the gear well to make space for a much stronger diagonal strut to the rear, that would extend all the way down to the point on gear leg where the catapult attachment point would be. Thus would allow the catapult force to be transmitted direct up the rear support strut into the airframe, without exerting a huge bending moment on the landing gear oleo struts.

The landing gears may also be made taller to allow the aircraft to touch down at higher angle of attack, as well as give greater clearance for any under belly stores that might be carried should the plane burst a tyre on a carrier deck landing.

mr.bean · Nov 16, 2015

Richard Santos said:
To make j-20 into a naval fighter will likely involve major changes to the shape and size of the wing and possibly canard, in addition to strengthening the airframe overall for the stresses of carrier takeoff and landings. The near delta shape of the j-20 wings are excellent for transonic and supersonic drag, but poor for low approach speed and handling. To improve carrier approach characteristics would likely involve giving j-20 wholly new wings with substantially reduced leading edge sweep, increased span, and increased area, along with larger high lift devices on the trailing edge, and possibly leading edge as well.

The main landing gear wheels would also likely be moved further aft relative to the aircraft's center of gravity to improve the aircraft's tendency to pitch down during wheel touch down. I wouldn't be surprised if it gains f/a-18 style kneeling main landing gear legs to help absorb landing shocks and move the wheels further aft without relocating wheel well.

I am going to guess the front landing gear leg would be relocated to the front of the gear well to make space for a much stronger diagonal strut to the rear, that would extend all the way down to the point on gear leg where the catapult attachment point would be. Thus would allow the catapult force to be transmitted direct up the rear support strut into the airframe, without exerting a huge bending moment on the landing gear oleo struts.

The landing gears may also be made taller to allow the aircraft to touch down at higher angle of attack, as well as give greater clearance for any under belly stores that might be carried should the plane burst a tyre on a carrier deck landing.

With that much changes and modifications, would they not be better to start with a clean sheet and custom design a next generation naval fighter?

Blitzo · Nov 16, 2015

mr.bean said:
With that much changes and modifications, would they not be better to start with a clean sheet and custom design a next generation naval fighter?

Possibly, but a navalized J-20 will likely still be lower risk, and if it meets the Navy's requirements then it's logical for them to go for it.

That said, we should wait and see just how comprehensive the structural changes and more importantly aerodynamic changes are.

coolieno99 · Nov 17, 2015

newguy02 said:
If this is the case, it looks like the FC-31's only hope left is export.

It's plan to be exported.

Li Yuhai, deputy general manager of AVIC, told reporters in November, “Since the start of the J-31's development, we have planned to use the plane to end some foreign nations' dominance of the fifth-generation fighter jet. One of its variants will be specifically designed for export,” Chinese media reported.

J-20 5th Gen Fighter Thread V

plawolf

Lieutenant General

kurutoga

Junior Member

Blitzo

Lieutenant General

newguy02

Junior Member

Alvaritus

New Member

Richard Santos

Captain

mr.bean

Junior Member

Blitzo

Lieutenant General

coolieno99

Junior Member

by78

General