Shenyang FC-31 demonstrators / J-35 naval fighter / J-35A land-based version

BLACK_MAMBA said:
VTOL requirements dominate the design of any air vehicle. Hence the F-35B influenced the layout, aerodynamics, structures etc of all three versions as the requirement on the JSF program was a common, or as common as possible airframe. Thus the F-35A and C versions are significantly compromised in terms of what their aerodynamic performance could have been. J-35 is effectively what F-35A and C should have been without the VTOL compromise.
Click to expand...
I'm of the belief that we don't really know enough about the J-35 to say how much it benefits from not having those same restrictions. Realistically I can't imagine its aerodynamic performance is all that different from the F-35A although it might benefit from a somewhat lower weight.

Ainen said:
They weren't compromised by the B version in any single way. I didn't bring up the Convair model 200 experience for nothing - it was a very specific program that specifically showed that a combination of CTOL and VTOL doesn't require compromises.
Moreover, the only significant problems B version brought into the program were (1)alcoa alloy troubles(specific to this version and not affecting others) and engine upgrade controversy.
Click to expand...
In my understanding some compromise was accepted as a result of the combination of requirement for the STOVL and CV variants. The STOVL variant imposed the length limitation so it could fit on the elevators of US Navy LHAs and LHDs. As a result, the original Lockheed ASTOVL-CALF-JAST design progression used a delta layout with canards. While I personally have a preference for a more conventional wing and tail, in this case the delta + canards configuration worked better within that length limit. Maybe it was also more suitable given the change in center of gravity for the lift fan.

Then when JAST became JSF they needed a CV version, and the Navy didn't find the flight characteristics of the existing design acceptable for CATOBAR operation, although I'm not aware of the specifics as to why. So the aircraft was redesigned with a more conventional wing and tail as demonstrated on the X-35. Boeing had to make a similar change at a late stage on their JSF design, likely because the Navy didn't like whatever testing of the X-32 had revealed. This is just speculation, but the conventional layout Lockheed switched to might have been better for stealth shaping too.

So overall it seems like the F-35 would have had better aerodynamics if it used either used the original delta + canards layout or if they had a few more feet of length to work with. But that isn't to say the F-35 is necessary a poor performer as it is.

For some reason the STOVL variant seems to get all of the blame for any and all performance compromises made with the F-35, but the CV variant was the late-comer to whole effort. Previous programs definitely seemed to reinforce the concept that you could field a very capable STOVL fighter along with a CTOL counterpart that would be entirely competitive to a similar design without any aspirations of performing vertical take-offs or landings. So, I can't fault the decision to pursue that concept. Fundamentally all aircraft design involves compromises to conform with restraints on size, engine power, cost, etc. to fulfill the required role. Same is true of most engineering in general I'd think.
 
BLACK_MAMBA said:
VTOL requirements dominate the design of any air vehicle. Hence the F-35B influenced the layout, aerodynamics, structures etc of all three versions as the requirement on the JSF program was a common, or as common as possible airframe. Thus the F-35A and C versions are significantly compromised in terms of what their aerodynamic performance could have been. J-35 is effectively what F-35A and C should have been without the VTOL compromise.
Click to expand...
I am not a fan of F-35, honestly I do not like it a lot, but here I think we should say F-35 is 3 different aircraft, so aerodynamics are not the same for the 3 different variants, a single engine powered fighter has an advantage in production less engines means easier to produce and make and cheaper this translates in more numbers see F-16 vs MiG-29.

Second is a single engine means smaller cross section, so it might look fatter but F-35 actually is thinner because a single engine powers the whole aircraft
 
The F-35B did drive a not-insignifcant amount of redesign to reduce weights due to the VTOL requirement. Due to the high amount of commonality between the versions, the weight reduction greatly improved the -A models.
 
F119Doctor said:
As the plane passes show center, you can see the smoke trail disappear and visible AB flames during the pull up and short shallow climb sequence. Back to Mil power w smoke trail as it levels off.

This was a comment on the apparent need for AB just to maintain speed under this non-challenging maneuver.
Click to expand...
All engines can generate smoke especially during throttle transients such as coming out of afterburner. That being said, the RD33 was especially prone to this, and the WS-13 and WS-21 from what I understand are essentially enhanced variants of that engine. I believe the WS-19 is supposed to be a clean sheet design, but not sure if that's what is being displayed.
 
Ainen said:
They don't, it's a (wrong) public "common sense". VTOL looks so different, VTOLs tend to fly worse - we have found the witch. Can we burn her?
The main reason behind JSF's performance compromises are requirements: single specified engine, A/C version carrying capacity, length limitation. Even "compromise" is perhaps a wrong word - it flies as specified.
The main troublemaker for the JSF program, though, is indeed the least common one of the 3 - you're right here. But it's the CATOBAR C version. Not B.

They weren't compromised by the B version in any single way. I didn't bring up the Convair model 200 experience for nothing - it was a a very specific program that specifically showed that a combination of CTOL and VTOL doesn't require compromises.
Moreover, the only significant problems B version brought into the program were (1)alcoa alloy troubles(specific to this version and not affecting others) and engine upgrade controversy.

VTOL doesn't limit length- it only limits the relative position of lift and center of mass during hovering.
This requirement doesn't limit aircraft of normal aerodynamic scheme, just takes away significant volume that is already there. You may or may not use it for lift purposes, simple as that.
Click to expand...
The F-35 was very much limited by the requirements of the STOVL version. That's why the Navy ended up with a single engine aircraft instead of the twin engine designs they prefer. It also limits the size of the aircraft due to the weight limitations of the STOVL requirement. To say it didn't affect the design is to quite literally not understand aircraft design or physics.
 
Spinmaster said:
emm….no? Before socialmedia there were magazines and televisions, neither of those are reachable by foreigners. CCTV has a freaking Channel specifically dedicated to this.View attachment 747780
Click to expand...
Not really, back in those days people do transport those magazines out of the country, and copy those television programme to platforms like youtube. The quality of those productions were, however, varied. The magazine cover (Aerospace Knowledge) you posted was well known for it's lack of quality articles, when compare with it's navy and army counterparts...
 
Sundog said:
The F-35 was very much limited by the requirements of the STOVL version. That's why the Navy ended up with a single engine aircraft instead of the twin engine designs they prefer. It also limits the size of the aircraft due to the weight limitations of the STOVL requirement. To say it didn't affect the design is to quite literally not understand aircraft design or physics.
Click to expand...
I fully believe the Navy needs a larger and more capable fighter than the Super Hornet and the F-35C, but to a large degree the Navy earned the way they were thrown into the JSF stew pot because of recent failures. The A-12 Avenger II program was a disaster, they weren't very enthusiastic about NATF so that was cut pretty quickly, and then a variety of factors put an end to the possibility of new Super Tomcats. Some of the A/F-X designs looked to have potential, but that program was still in an early stage and who knows what option the Navy would pursue there? They could have also screwed that one up.

Admittedly not all of this was their fault. For example, a lot of political influence seems to have been opinionated against new F-14s. But a lot of the rest of it was due to poor choices the Navy made. On paper a carrier variant of the JSF gave the USN a useful strike/attack fighter probably comparable to at least some of the A/F-X designs being considered, while leaving most of the program to be managed by anyone but the Navy. But things are rarely that simple and easy.
 
Last edited:
Sundog said:
The F-35 was very much limited by the requirements of the STOVL version. That's why the Navy ended up with a single engine aircraft instead of the twin engine designs they prefer. It also limits the size of the aircraft due to the weight limitations of the STOVL requirement. To say it didn't affect the design is to quite literally not understand aircraft design or physics.
Click to expand...

Single engine was there since the very beginning, going down from air force request since before usmc vtol program was merged in. One engine is cheaper and smaller than two, simple as that.

For navy, much later when they joined, it meant that they either join the program as is, or don't get a new aircraft in 2010s at all(without real option of saying no). F-35b and USMC just wasn't important enough to mandate something this big.

There is nothing that prevents multiple engine VTOLs; in fact, they weren't even a majority. Please don't use word physics as a magical defense word.

There's already a j-35 for you - and this one is a significantly longer aircraft.
 
Thing that bothers me about the state of affairs in the US is it looks like neither the FA/XX or NGAD will be using 3-stream engines and will likely be using a slimmed down F135 or one of the new engines with the 3rd stream stripped out. No more F414-sized engines going forward.
 
sferrin said:
Thing that bothers me about the state of affairs in the US is it looks like neither the FA/XX or NGAD will be using 3-stream engines and will likely be using a slimmed down F135 or one of the new engines with the 3rd stream stripped out. No more F414-sized engines going forward.
Click to expand...
I'm not sure about that.

Because an 85klb MTOW/55klb trap weight aircraft needs about 70klbs thrust for 1:1 T:W at 50% fuel. 70klbs is 2x F119 class. A pair of F135s or the big adaptive engines is enough to have better than a 1:1 T:W at takeoff.
 
Ainen said:
Single engine was there since the very beginning, going down from air force request since before usmc vtol program was merged in. One engine is cheaper and smaller than two, simple as that.

For navy, much later when they joined, it meant that they either join the program as is, or don't get a new aircraft in 2010s at all(without real option of saying no). F-35b and USMC just wasn't important enough to mandate something this big.

There is nothing that prevents multiple engine VTOLs; in fact, they weren't even a majority. Please don't use word physics as a magical defense word.

There's already a j-35 for you - and this one is a significantly longer aircraft.
Click to expand...
There have been very few multi engine VTOLs... You are looking at P.1154 design studies and maybe a few concept demonstators in the 60s? The fact that most successful VTOL designs are single engined, usually balanced with lift jets (usually also marked with lower reliability and increased risk) if not the Harrier tells you a lot about the confidence in multi-engine systems in hover. And yes, physics plays a part. The more engines you have, the more the aircraft mass grows, the bigger the thrust you need for VTOL. And you are back to a fundamental constraint imposed by the VTOL requirement.

The length restrictions has been mentioned to death, again as far as I can tell only an issue on smaller carrier lifts - for the VTOL variant to operate and fit on...

I am not sure why there is a debate on this. The F-35 is fundamentally driven and limited by needing to accomodate the VTOL version. It doesn't make the aircraft itself useless however. It just means that in reality a common systems, instead of airframe approach would probably have resulted in better adapted (and one could argue more capable in their specific enviroment/role) aircraft for each service.
 
GcT7EiTbAAAyGfo
 
Here's an interesting video by Alex Hollings from Sandboxx concerning whether or not the J-35 is a good design:


Last week, China officially unveiled the nation’s second domestically developed 5th-generation fighter, known officially as the J-35. This new twin-engine stealth fighter, which comes in both runway and carrier-capable variants, is meant to bolster China’s rapidly expanding fleets of larger J-20 stealth fighters, and maybe even to end America’s global monopoly on exporting stealth aircraft.
Click to expand...
Citations:
https://web.archive.org/web/201411210...https://www.youtube.com/redirect?ev...ghter-disappoints-first-display&v=bJFRW8ul4RY
https://www.globalsecurity.org/milita...https://www.youtube.com/redirect?ev...g/military/world/china/ws13.htm&v=bJFRW8ul4RY
https://theaviationist.com/2021/10/29...https://www.youtube.com/redirect?ev...m/2021/10/29/j-35-first-flight/&v=bJFRW8ul4RY
https://www.sps-aviation.com/story/?i...https://www.youtube.com/redirect?ev...PLAAF-and-JF-17-of-PAF-Analysed&v=bJFRW8ul4RY
https://thedefensepost.com/2022/08/02....
https://www.sandboxx.us/news/americas....
https://www.safety.af.mil/Portals/71/...https://www.youtube.com/redirect?ev...tics/USAF%20Single%20Engine.pdf&v=bJFRW8ul4RY
https://web.archive.org/web/202308062...https://www.youtube.com/redirect?ev...-come-into-focus/154356.article&v=bJFRW8ul4RY
https://web.archive.org/web/201509241...https://www.youtube.com/redirect?ev...hbeam.com/doc/1G1-97131209.html&v=bJFRW8ul4RY
https://theaviationist.com/2021/10/29...https://www.youtube.com/redirect?ev...m/2021/10/29/j-35-first-flight/&v=bJFRW8ul4RY
https://web.archive.org/web/201511110...https://www.youtube.com/redirect?ev...vics-new-stealth-fighte-418777/&v=bJFRW8ul4RY
https://www.washingtonpost.com/world/...https://www.youtube.com/redirect?ev...35a-stealth-fighter-jet-russia/&v=bJFRW8ul4RY
https://www.twz.com/air/chinas-j-35a-...https://www.youtube.com/redirect?ev...fighter-officially-breaks-cover&v=bJFRW8ul4RY
https://www.navalnews.com/naval-news/...https://www.youtube.com/redirect?ev...-of-chinese-navys-j-35-fighter/&v=bJFRW8ul4RY
https://warriormaven.com/china/china-...https://www.youtube.com/redirect?ev...alth-jet-to-rival-us-navy-f-35c&v=bJFRW8ul4RY
https://www.cnn.com/2019/05/14/politi...https://www.youtube.com/redirect?ev...adow-war-chinese-spy/index.html&v=bJFRW8ul4RY
https://www.sandboxx.us/news/the-man-...https://www.youtube.com/redirect?ev...cas-stealth-fighters-for-china/&v=bJFRW8ul4RY
https://www.secretprojects.co.uk/thre...https://www.youtube.com/redirect?ev...and-based-version.13939/page-14&v=bJFRW8ul4RY
https://www.twz.com/42920/chinas-carr...https://www.youtube.com/redirect?ev...pable-stealth-fighter-has-flown&v=bJFRW8ul4RY
https://theaviationist.com/2021/11/02...https://www.youtube.com/redirect?ev.../state-of-china-naval-aviation/&v=bJFRW8ul4RY
https://www.twz.com/sea/chinese-aircr...
Click to expand...
 
Last edited:
I am currently in the process of contesting one of his B-21 videos where he (or someone on his team) decided to use some of my artwork without permission, so you can get an idea of the character of these folks :)
 
Hollings is just on the content mill farm.

Having to regularly push out content without genuine humility, and on one's own schedule, where one's livelihood is on the line, puts common sense and potentially integrity out of one's priorities.
 
AGS-1787 said:
Why does the cockpit opens forward like the f-35?
Click to expand...
To seal the frontal opening of the canopy better (I believe) and thus reduce it's impact on the most critical sector of the RCS. At least this is the main reason why Kaan also has it.

1000006452.jpg

It's also easier to remove the seat and do maintenance this way. (Which might be a big plus when you're in the hangar of a CV.)
 
Last edited:

Similar threads

Please donate to support the forum.

Back
Top Bottom