Featured Project Azm: Pakistan's Ambitious Quest to Develop 5th Generation Military Technologies.

[Shabi1]

Stealth and Canards don't go together

https://www.quora.com/Is-Chinese-fi...s-of-a-fighter-jet-reduce-its-stealthy-nature

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[Image credits : Martian2]

For a start we need to define certain terms in layman language : For a Fifth-Gen fighter jet, the smaller the radar cross section (RCS), the better stealth feature it has and the harder for enemy aircraft to detect it - In short, a Fifth-Gen fighter jet’s stealthy nature comes from its frontal and lower fuselage RCS. Many people have the misconception that canards on a fighter jet drastically increases its RCS due to deflections off the canards and exposes the fighter jet to early detection. Let’s set the record straight - Canards on a fighter jet does not necessarily increase its frontal RCS, especially when there is planform alignment.

As Dr Michael J Pelosi and Dr Carlo Kopp pointed out in their assessment of[1]J-20’s RCS , the frontal RCS of the J-20 presents robust Very Low Observable (VLO) performance against X-band and S-band radars - canards included. Furthermore, South Korea and Indonesia's joint KF-X 5th gen fighter project selected a canard-delta configuration for their final aircraft. Even the Dassault Rafale has a lower RCS than the F-18 Hornet despite it having canards and the F-18 being a traditional configuration fighter. If canards were an impediment to VLO performance, Chengdu would not have selected the J-20's canard-delta configuration and neither would KAI have chosen the same configuration for their 5th gen fighter jet program.[2]

Northrop Grumman - and they are not unknown in the field of stealth - proposed a delta-canard derivate of the ATF/YF-23 for the NAT program and the latest proposal for Boeing's 6th generation fighter is also a delta-canard design!

McDonnell Douglas X-36 in 90's has similar canards configuration as J-20, NASA says that it was extremely stealthy from all angles.

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[Armchair]

I get the point @Shabi1 is making. i.e. That a stealth 5th generation may have canards.

My problem with canards is three-fold:

1. Canards increase drag, compared to a pure tailless delta.
2. Canards increase RCS, compared to a pure tailless delta.
3. Canards increase weight and complexity (cost), compared to a pure delta.

 

[Suff Shikan]

Ladies and gentlemen, I bring to you the design of the Azm project (rumor). This picture that you view here, is your Azm 5th generation stealth fighter. It appears to look like a mini-J-20. Even has tiny canards positioned like a Rafale, closer to the main wing.

looks like cross of F-16 and F-22

 

[Shabi1]

I get the point @Shabi1 is making. i.e. That a stealth 5th generation may have canards.

My problem with canards is three-fold:

1. Canards increase drag, compared to a pure tailless delta.
2. Canards increase RCS, compared to a pure tailless delta.
3. Canards increase weight and complexity (cost), compared to a pure delta.

Your points are valid that is why it's a balancing act, you gain some advantages but their are setbacks associated as well. Have to choose optimal mix

The canards impact on the RCS is that of tail plane. From the designer of the J-20 they chose canards to increase lift, range and the added lift allowed them to reduce wingspan (can be googled up). So they had a cumulative impact on RCS and drag to consider and would have been favorable so they went with it.

On the other hand SU-35 designers decided to delete the canards from the flanker series.

Some 6th gen concepts have canards but deleted vertical stabilizers to reduce weight and drag.

You might be interested to know that besides a B-2 type bomber China is also rumored to have supersonic bomber concept very similar to the YF-23 design.

 

[Armchair-General]

Are there any leads on the RD93MA that was being designed by Russia specifically for the FC1/JF 17. Longer life and larger thrust. It could power the Azm.

 

[Armchair]

Your points are valid that is why it's a balancing act, you gain some advantages but their are setbacks associated as well. Have to choose optimal mix

The canards impact on the RCS is that of tail plane. From the designer of the J-20 they chose canards to increase lift, range and the added lift allowed them to reduce wingspan (can be googled up). So they had a cumulative impact on RCS and drag to consider and would have been favorable so they went with it.

On the other hand SU-35 designers decided to delete the canards from the flanker series.

Some 6th gen concepts have canards but deleted vertical stabilizers to reduce weight and drag.

You might be interested to know that besides a B-2 type bomber China is also rumored to have supersonic bomber concept very similar to the YF-23 design.

That's quite true, it's a balancing act with tradeoffs. If we look at the Mirage 2000, its obviously capable as a design both in BVR and WVR.

The advantage of the Mirage 2K is that despite a weak engine (not dissimilar to an RD-93), its design enables it to go toe-to-toe with the F-16.

At the same time, it has superior high altitude performance. Which is the prime arena of future BVR combat. High speed, high altitude launches extend the range and NEZ.

Does PAF really need anything better than a stealthy Mirage 2000? It's a simple and effective design, with inherent stealth. Easy to R&D, cheap to maintain (the design, not the French gamesmanship), and cheap and easy to build.

Now, if you want to improve upon the M2K design, you could add a V tail. And to lower the need for wing area and stabilizers, use TVC, further improving high altitude maneuverability.

To take it one step further, you could have small canards built with dielectric material (invisible to radar). This is actually not that expensive, its basically Corning glass and epoxy. Its very similar to what the radome of a fighterjet is made out of.

But even without these canards, you should have the general plane, with V tails and TVC, that provides a better balance than a M2K.

Shouldn't an important aspect of the design be Keep it Simple?

The Chinese bomber you posted looks brilliant, BTW. Big fan of the F-23.

 

[enroger]

I get the point @Shabi1 is making. i.e. That a stealth 5th generation may have canards.

My problem with canards is three-fold:

1. Canards increase drag, compared to a pure tailless delta.
2. Canards increase RCS, compared to a pure tailless delta.
3. Canards increase weight and complexity (cost), compared to a pure delta.

All that is true to a certain degree, depends on the designer to decide whether the gain of pitch authority and vortex lift in high AoA is worth the cost. A pure delta would definitely has the least drag. On that note I think the Russian movable LERX on their Su-57 is an interesting design, though less powerful in vortex generation.

M2

That's quite true, it's a balancing act with tradeoffs. If we look at the Mirage 2000, its obviously capable as a design both in BVR and WVR.

The advantage of the Mirage 2K is that despite a weak engine (not dissimilar to an RD-93), its design enables it to go toe-to-toe with the F-16.

At the same time, it has superior high altitude performance. Which is the prime arena of future BVR combat. High speed, high altitude launches extend the range and NEZ.

Does PAF really need anything better than a stealthy Mirage 2000? It's a simple and effective design, with inherent stealth. Easy to R&D, cheap to maintain (the design, not the French gamesmanship), and cheap and easy to build.

Now, if you want to improve upon the M2K design, you could add a V tail. And to lower the need for wing area and stabilizers, use TVC, further improving high altitude maneuverability.

To take it one step further, you could have small canards built with dielectric material (invisible to radar). This is actually not that expensive, its basically Corning glass and epoxy. Its very similar to what the radome of a fighterjet is made out of.

But even without these canards, you should have the general plane, with V tails and TVC, that provides a better balance than a M2K.

Shouldn't an important aspect of the design be Keep it Simple?

The Chinese bomber you posted looks brilliant, BTW. Big fan of the F-23.

M2K has excellent instantaneous turn rate, makes her very scary on initial merge. However compared on F-16, M2K loses energy fast in high-g turns, not a good energy fighter. I believe all the delta-wing family shares this trait (J-10, J-20 ,EF-2000...etc), depends on wing sweep angle, the steeper the angle the more M2K like...

 

[帅的一匹]

J20 is never designed for dog fighter, it's a hit-and-run fighter, a sniper.

That's why it doesn't have machine gun.

Is it possible to mount a laser gun on J20 in the future?

 

[Armchair]

Maybe but first you need to make a ground based AAA using laser. The US already has this deployed, including in their new cruisers.

 

[enroger]

J20 is never designed for dog fighter, it's a hit-and-run fighter, a sniper.

That's why it doesn't have machine gun.

Is it possible to mount a laser gun on J20 in the future?

J-20 probably have similar energy characteristic to J-10 in subsonic regime, in super-sonic regime J-20 would be a class of her own even with just WS-10B engine. So it;s not that she can't dog fight, its just not her strong suit compared to other 5th gen (except fat lightning haha...)
Newer generation high off-bore IR missile like PL-10 might even eliminate the need for traditional dogfight where you don't need to point your nose to the enemy to get a firing solution.

 

[dBSPL]

(except fat lightning haha...)

Fat but True.
ps: No rocker smiley on PDF

 

[MastanKhan]

J20 is never designed for dog fighter, it's a hit-and-run fighter, a sniper.

That's why it doesn't have machine gun.

Is it possible to mount a laser gun on J20 in the future?

Hi,

For a laser gun---you might need a mini nuc reactor on the aircraft.

And you are correct---the J20 is for BVR combat only---absolutely stupid to get into a dog fight---.

 

[帅的一匹]

According to big Shrimp in China defence, WS19 medium turbo fan engine with 10+tons wet thrust is ready to test on fighter jet. This might be the powerplant to be installed on J31 for PLAN.
And WS15 engine according to PuPu(another big shrimp), is going smoothly under development.

Hope those hundreds billions investment in aviation Engine industry will pay off.

Hi,

For a laser gun---you might need a mini nuc reactor on the aircraft.

And you are correct---the J20 is for BVR combat only---absolutely stupid to get into a dog fight---.

PL10 and new HMD are all you need in WVR.

China shall mass produce J31 and J20 to prepare possible show-down with USA.

 

[Thorough Pro]

Canards increase the RCS

Tell me why

 

[CHI RULES]

The 5th Gen jets like F35, F22 or even J20 and FC31 can be assumed to have far superior detection capabilities at longer ranges so chances of dog fight shall be almost zero in case of China, Russia or USA. However scanrio may be changed in case of Indo-Pak scenario so chances are that both air forces shall deploy specialized versions which shall have capability of effective WVR engagements as well.