Ask anything Thread (Air Force)

[lcloo]

China does not need a single engined gen 5 fighter jet, this aircraft is the wish of other countries that cannot afford to buy and operate the expensive twin engine 5th gen fighter.

The reason being
1) complication of logistic management and human resource management for having 3 types of 5th gen fighters
2) why develop a new 5th gen fighter for PLAAF when 6th gen fighters are in development stage? Won't this take away development fund for 6th gen?
3) local point air defence belonged to the era of short range J6 and J7 fighters, today's air defence emphasis is on 1st and 2nd island chains.

The real question is will China develop a new single engined 5th gen fighter for export purposes, just like JF-17 Thunder. Will there be enough export sales order to justify the development costs? Remember the sales failure of F-20 Tiger Shark?

 

[gelgoog]

Who is to say that the design needs to be 5th gen? It could be 5.5 gen or 6th gen even if they want to.

They already have existing airframe designs they can consider like the US McDonnell Douglas X-36 or Boeing Bird of Prey demonstrators.
Both of those airframes reduce radar cross section further by not having vertical surfaces on the tail. I suspect whatever airframe they come up with for NGAD or F/A-XX will also dispense with vertical surfaces.

So, basically a new airframe design without vertical surfaces, powered by a single WS-15 engine, with stealth nozzle, optionally manned.

 

[Michaelsinodef]

I honestly think some sort of drone could 'replace' the J10, or at the very least, kind of take on the role of a single jet engine fighter.

It would be a very high tech, expensive drone (that would need something like a WS15), but still a drone.

 

[99PLAAFBalloons]

Are there any functional differences between a J-11B(S) and a J-11B(S)H beyond designation? If not, do we think the PLANAF jets will be re-designated?

@Deino (Will endeavour to order your book in the future )

 

[ACuriousPLAFan]

China does not need a single engined gen 5 fighter jet, this aircraft is the wish of other countries that cannot afford to buy and operate the expensive twin engine 5th gen fighter.

The reason being
1) complication of logistic management and human resource management for having 3 types of 5th gen fighters
2) why develop a new 5th gen fighter for PLAAF when 6th gen fighters are in development stage? Won't this take away development fund for 6th gen?
3) local point air defence belonged to the era of short range J6 and J7 fighters, today's air defence emphasis is on 1st and 2nd island chains.

The real question is will China develop a new single engined 5th gen fighter for export purposes, just like JF-17 Thunder. Will there be enough export sales order to justify the development costs? Remember the sales failure of F-20 Tiger Shark?

Who is to say that the design needs to be 5th gen? It could be 5.5 gen or 6th gen even if they want to.

They already have existing airframe designs they can consider like the US McDonnell Douglas X-36 or Boeing Bird of Prey demonstrators.
Both of those airframes reduce radar cross section further by not having vertical surfaces on the tail. I suspect whatever airframe they come up with for NGAD or F/A-XX will also dispense with vertical surfaces.

So, basically a new airframe design without vertical surfaces, powered by a single WS-15 engine, with stealth nozzle, optionally manned.

I honestly think some sort of drone could 'replace' the J10, or at the very least, kind of take on the role of a single jet engine fighter.

It would be a very high tech, expensive drone (that would need something like a WS15), but still a drone.

I think I'll go all-at-once, easier that way.

To clarify, if there is the need and incentive to develop and build one, China certainly can come up with a single-engine fighter model, which certainly isn't limited to 5th-gen only. Of course, 5.5th-gen or even 6th-gen is possible.

However, as @lcloo had explained, it doesn't make much sense for China to procure proper single-engine fighters to be used as the main fighting assets for the PLAAF and PLANAF in war, whether the fighter is a 5th-, 5.5th- or 6th-gen.

This is also considering the significant upgrades and advances expected to be present on 5th-, 5.5th- and 6th-gen fighters into the future, which are only getting ever power-hungry-IER than before - And here, I strongly believe that having only one engine may no longer be sufficient at providing enough power to keep all those computer systems onboard running (just look at the ongoing debacle with the F-35's engines).

Besides, all conceptual illustrations of 6th-gen fighters that have been published around the globe right now (NGAD, F/A-XX, GCAP, FCAS, PAK-DP, LDJ-XX (China's 6th-gen, notional designation), etc) shows twin-engine designs. Therefore, I believe that twin-engine designs are going to be the mainstream for proper fighter jets in the future.

But, just slid in some food-for-thought deviation.

~~~

After some thoughts, I believe that China could pick either one of the two options that I could think of in order to develop a single-engine 5/5.5/6th-gen fighter:

#1 - A true-purpose single-engine light fighter (e.g. Su-75).
This light fighter would be fully equipped with advanced features typically found on other 5th-gen fighters and future 6th-gen fighters. Therefore, this light fighter will the more capable of the two options.

But, as I have mentioned above - Although the benefits brought by the single-engine 5/5.5/6th-gen fighter is commendable, yet since China has no need for single-engine 5/5.5/6th-gen fighters, hence this light fighter would only be viable for the export market.

This brings alongside some caveats associated with the developmental and sale of the fighter itself:
- The developmental project would have to be funded by the company(ies) responsible for the development of the fighter, as the Chinese government is unlikely to help funding something that isn't expected to see usage by the PLA;
- The price tag of the fighter would be comparably higher than the below option (though still lower than proper twin-engine fighter jets), hence the marketability of the fighter to overseas customers could be rather limited (though still not as limited as trying to market proper twin-engine fighter jets); and/or
- The risks whereby the profit earned from the sales of the fighter being unable to cover the relatively higher developmental cost of the fighter (hence incurring significant losses for the company(ies)) is much higher, etc.

#2 - A dual-purpose single-engine jet trainer-cum-light fighter (e.g. JL-8 and T-7).
This jet trainer/light fighter would only be equipped with some of the advanced features typically found on other 5th-gen fighters and future 6th-gen fighters. Conversely, this jet trainer/light-fighter would be equipped with all, yet reduced to a certain degree of advanced features typically found on other 5th-gen fighters and future 6th-gen fighters. Therefore, this jet trainer/light fighter will the less capable of the two options.

Despite the caveats, however, there are several benefits associated with this approach:
- The versatility of the fighter's role means that there is still likely to have markets in China, i.e. becoming advanced jet trainers for PLAAF and PLANAF cadets (complementing or replacing JL-10s) to undergo 3rd-stage (advanced) fighter pilot training, before graduating onwards to fly proper 5th and 6th-gen fighters;
- The developmental project might be able to receive funding from the Chinese government;
- The comparably cheaper price tag than the above option could open the marketability of the fighter to greater number of foreign customers with shallower pockets; and
- Cheaper developmental costs means lower risks of incurring loss from the sale of the fighter (or conversely, higher chances of earning profits) for the company involved in the fighter's developmental project, etc.

So, it depends on which option is the preferable choice for China. (Personally, the 2nd choice is more attractive for me. But, eh.)

~~~

Bringing back the discourse on whether China needs a single-engine 5/5.5/6th-gen fighter at all - @Michaelsinodef's idea is actually better, IMO. Similarly, @99PLAAFBalloons and @Blitzo have also discussed on this topic, so I won't dive any deeper.

Tl; dr - If China intends on developing a single-engine 5/5.5/6th-gen fighter for active service by the PLAAF and PLANAF, might as well for her to develop loyal wingman-type UCAV fighters based around that premise instead.

As an addition - With the growing capabilities of 6th-gen fighters and wingman-type UCAV fighters (and thus, their dimensions and weights), it will only be a matter of time before loyal wingman-type UCAVs become as large and as heavy as the medium-weight, medium-size fighters of today*.

*Regarding the bolded sentence: Of course, this also applies to other types of large UCAVs that are non-fighters (e.g. bombers, tankers, AEW&C, ASW ELINT, SIGINT, EW, ECM etc). But this is going beyond the current scope of discussion, so I'll stop here.

 

[MarKoz81]

BUT, just for a little food-for-thought discussion - If there is really a demand and incentive for it, then China can absolutely develop a single-engine 5th-gen fighter.

The single engine 5gen isn't a great idea but a terrible one.

You want food for thought?

1. Why is there no single-engine 5gen apart from F-35?
2. Why were there single-engine and twin-engine fighters?
3. What determines what choice is appropriate?
4. What is the cost breakdown for maintenance between engine and the rest of the aircraft systems?

I'll give you the answers below but do try to answer these on your own before reading further.

============

1. Why is there no single-engine 5gen apart from F-35?

Because F-35 is not a fighter aircraft. It's a scam. Actually a series of scams. It's also a product created to corner the market. It's only "successful" because there's no competition.

It began in the 80s as a DARPA project for a stealthy STOVL aircraft for USMC. Lockheed patented the solution used in F-35B and shared it with PW to develop a preliminary design. Once the project was completed the estimated cost was too high for it to materialize so the project was expanded to include USAF and bring down the unit cost. Because Lockheed and PW cooperated on a proprietary design including it in requirements could decide the outcome of a competitive tender. Lockheed made convinced USAF that their solution allowed to replace the lifting fan with a fuel tank giving the plane double combat radius of F-16 and that ensured that USAF and USMC programs were merged. Lockheed deliberately cooperated with Yakovlev in early 90s to restrict Yak-141 technology and in 1996 the conditions for JSF were set and with two participants of which only Lockheed had a functioning solution. Between that, ATF and the mergers the market for 5gens was effectively cornered even before the fly-off.

So the reason why F-35 has a single engine has nothing to do with the cost of the engine or its performance - which became problematic as requirements grew the mass of the "light" fighter to more than that of F-15. It had everything to do with how that specific single engine derived from F119 for F-22 with STOVL solution decided the outcome of a tender.

And this is why there is no single-engine 5gen. It is not economical to do so. Also this is why Su-75 is a scam to get money and not a revolutionary design.

2. Why were there single-engine and twin-engine fighters?

It had to do with energy and flight parameters of the aircraft. Engines produce thrust. Thrust moves mass against gravity and imparts momentum which is useful for launching missiles and retaining energy for flight maneuvers.

Engines have their efficiency that is determined by technology. F-16 had very good engines which is why it had a single engine capable of giving 8,5/19t (empty/MTOW) aircraft better flight parameters than MiG-21 - a mainstay of Warsaw Pact forces when F-16A entered service - at 5,8/8,8t

It all mattered because until 1991 when the only fire-and-forget missiles were WVR IR missiles and BVR missiles were SARH - requiring continuous illumination of target until impact - and both were not very good with the BVR missiles being even worse. So dogfighting existed as a viable tactic because missiles weren't particularly effective.

This is why MiG-29 was a big deal in 1983 - a twin-engine, very powerful (20% better climb, ceiling and speed than F-16) "light" fighter with new R-73 and helmet-mounted cueing and an IRST. It was a beast that ate F-16As for breakfast and also had R-27 that F-16C only got much later. Now it's seen as obsolete because Sukhoi won the war for the market in Russia by lying about PAK-FA and MiG has no real support for 29SMT/35. It was very much not the case in 1983 when Fulcrum was a mature design (apart from radar, which got downgraded) while Flanker struggled. Germany got DDR's MiGs and flew them against NATO planes in early 90s. They were the only thing that Germany kept from the entire extensive DDR arsenal.

Then AMRAAM changed everything and perception of what is a good fighter changed with it.

WVR became obsolete even before new generation of highly maneuverable WVR missiles like ASRAAM, IRIS-T or AIM-9X ensured that it was fatal on launch. Without support and R-77 Fulcrum became obsolete just as F-16 would be in such conditions. F-16As weren't that much better than MiG-21 bis or MiG-23MLD but they had support.

3. What determines what choice is appropriate?

The required energy for performance and availability of engine models. It's that simple.

Of course aerodynamics is a factor which influences mass distribution but it's not decisive.

Reliability is also a factor, bigger for naval planes, although not a necessity. But two is almost always better than one including in terms of engine production. It's easier to build a less powerful engine so two weaker engines may bring savings overall compared to one more powerful and expensive engine. This is why Eurofighter and Rafale fly with two instead of one.

4. What is the cost breakdown for maintenance between engine and the rest of the aircraft systems?

Unfortunately I can't give you numbers but I can give you examples.

Poland had in 1991 three main types:

• MiG-29A (2x RD-33) since 1990
• MiG-23MF (1x R-29) since 1978
• MiG-21bis (1x R-11) since 1980

MiG-23 was retired in 1998 because of the engines which were using up quickly due to their (deliberately) inefficient design. MiG-21 was operated until 2003 because despite poor engine life it was well understood and with large fleet of aircraft it could be maintained well. MiG-29s was bought from USSR with full maintenance kit so it keeps flying to this day. Two more expensive but better engines can be cheaper over the life of an aircraft than one cheaper but worse engine. And the difference in cost between F-16s bought in 2003 and MiG-29s is very significant.

Finland used single-engine MiG-21 and J35 Draken and in the 90s bought twin-engine F-18C. AIM-7 and AIM-120 were a consideration but not the deciding factor because by then F-16C was available with the missile. Reliability and maritime environment were primary factors. Cost turned out to not be an issue.

Why does every country keep buying F-16s? Because Lockheed Martin is best at lobbying and corruption and they fight to keep their market cornered. They never produced a fighter that wasn't bad in at least one major way. You think F-22 is great? Think again... Have you ever seen the plane in action? F-18s are better all around but they have the Navy as backer in DoD.

Sweden used single-engine JA27 Viggen (PW JT8D)which was too expensive for Sweden and chose single-engine JAS39 (GE F404) which was meant to be cheaper. Where was the difference? In many small details of the entire plane. The number of engines didn't matter.

Also increasingly the cost of the aircraft shifts not only to bespoke electronics but software as well. The radars in 1980s were crude. The rest of the electronics even cruder. Modern aircraft must have AESA radars to have a shot against EW. They must have EW systems. They must have electro-optical sensors. They must have multi-directional communication links. If you add VLO then the airframe becomes a major cost item.

Rafale is an expensive plane with two expensive but relatively weak engines. It doesn't matter once you accept the cost of radar, EW and the rest of the systems and - most importantly - lifecycle support with all upgrades and updates and weapon integration.

Engines - unless they are high-performance items like F135 or WS15 - become less of a factor and modern missiles put far less demand on energy of the plane. Payloads not platforms. Systems not weapons.

So what about engines?

• KF-21 has 2x GE F414
• TF-X has 2x GE F110 (later: domestic)
• Indian projects have 2x GE F414
• FC-31 has 2x WS13

Notice a pattern? Two cheaper engines with design and part commonality. Not one expensive high-end engine.

And for UCAVs? One cheaper engine with design and part commonality.

Engines wear out during use. Cheap may not only be better at high intensity operations. It may be the only thing that works.

============

Are you happy with this answer? Well, you have to be, because you're not going to get anything else no matter how hard you dig. Unless you ask Sukhoi of Lockheed but then be ready to be scammed.

 

[Kich]

A general question but what fighter aircraft are in production across PLA?
J-31/35, J-20, J-16, J-15, and J-10?

 

[FriedRiceNSpice]

A general question but what fighter aircraft are in production across PLA?
J-31/35, J-20, J-16, J-15, and J-10?

J-31/35 is almost certainly not in production yet. Current J-10 production status is not known at the moment: most recent production was for fulfillment of export orders to PAF and the production lines were rumored to be pending relocation to Guizhou, which may result in a pause in production. Unknown whether new production lines will be for export orders only or additional units for PLAAF. The other three (J-20, J-16, J-15) can be considered to be in production, with J-15 production taking place at a significantly slower pace.

 

[davidau]

J-31/35 is almost certainly not in production yet. Current J-10 production status is not known at the moment: most recent production was for fulfillment of export orders to PAF and the production lines were rumored to be pending relocation to Guizhou, which may result in a pause in production. Unknown whether new production lines will be for export orders only or additional units for PLAAF. The other three (J-20, J-16, J-15) can be considered to be in production, with J-15 production taking place at a significantly slower pace.

I often wonder why some fighter jets have pitot tube, others don't. What determines this requirement? For example, J15 carrier borne jets have pitot tube, J16 don't

 

[tamsen_ikard]

How good is China's air defence coverage?

Ukraine war has shown Air Defence is the most important aspect of warfare at the moment, when it comes defending against air attacks from fighters, drones and missiles.

Does China have homegrown s-400 level system? How many units of HQ-9 does China have, which is equivalent to s-300?