Chinese Engine Development


Xsizor

Junior Member
Registered Member
Yes, we know that under ideal conditions the F135 can reach 220 kN. The J-20 and F-35 should be seen as twins when it comes to engines; the J-20 is currently hobbled by a crap engine, while the F-35 is also hobbled by non-mature engines. The US often tends to just negate aerodynamic disadvantages by increasing thrust; see the P-51s and the history of American aviation up until the present day. While the F-35 may be a crap or mediocre dogfighter today, future thrust increases (10% thrust increase from 190kN to 219kN is essentially resting thrust) will make the F-35 more competent and capable in WVR.
Re-read what you typed in when you are sober.
F135 cannot sustain 220 kN. It has around 190kN max thrust. (If recent reports are to be believed - neither the engine or the aircraft can sustain even the max thrust of 192 kN.)
"US often tends to negate...thrust"
No. US actually is well balanced when it comes to thrust and aerodynamics. F-35 is a single engine fighter that was never intended to be an air superiority fighter. It isn't bad in what it does. The problem is that it tries to accomplish a lot.
"J-20 is currently hobbled by a crap engine"
No. It isn't. AL-31 series powers a lot many aircrafts (flankers) across the planet. It is a great engine that does what it says on the lid. J-20 however requires an even more powerful engine to realize it's full potential as a fifth gen fighter. The Chinese have tested a 155 kN WS-10 engine too on the J-20. Seems like there are plan-A,B and even C.
"10% increase from 190 to 219"
10 percent increase means 0.1*190 + 190 = 209.
So it is around 210 Kn . But it is still 10 kN less than 220 kN.
 
Yes, we know that under ideal conditions the F135 can reach 220 kN. The J-20 and F-35 should be seen as twins when it comes to engines; the J-20 is currently hobbled by a crap engine, while the F-35 is also hobbled by non-mature engines. The US often tends to just negate aerodynamic disadvantages by increasing thrust; see the P-51s and the history of American aviation up until the present day. While the F-35 may be a crap or mediocre dogfighter today, future thrust increases (10% thrust increase from 190kN to 219kN is essentially resting thrust) will make the F-35 more competent and capable in WVR.
Well, I think the situation is quite different between the 2.

The J-20 is currently limited by the highest powered AL-31s which aren't as phenomenal in thrust as would be ideal but still quite the powerful engine and J-20 will have very competitive kinematics with possibly some weight trade-offs in what it carries. No doubt, as technology grows, more things can be added to the J-20 as large fighters have large upgrade potential and a better engine would be needed to preserve/enhance flight performance while adding those upgrades in.

F-35, on the other hand, cannot even fully use the current engine not to mention a 220kN version. With afterburners engaged for a certain time at speeds in excess of Mach 1.2, the F-35's rear sections start falling apart. So if I were a decision maker in the F-35 program, boosting the engine power would not be my concern even though performance-wise, it needs it.

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(June 12, 2019)

At extremely high altitudes, the U.S. Navy and Marine Corps’ versions of the F-35 jet can only fly at supersonic speeds for short bursts of time before there is a risk of structural damage and loss of stealth capability, a problem that may make it impossible for the Navy’s F-35C to conduct supersonic intercepts."

Both deficiencies were first observed in late 2011 following flutter tests where the F-35B and F-35C both flew at speeds of Mach 1.3 and Mach 1.4. During a post-flight inspection in November 2011, it was discovered the F-35B sustained “bubbling [and] blistering” of the stealth coating on both the right and left sides of the horizontal tail and the tail boom.

During similar tests of the F-35C in December 2011, “thermal damage” that compromised the structural integrity of the inboard horizontal tail and tail boom were apparent.

The Defense Department has also instituted time limits on the number of seconds the F-35B and F-35C can fly at speeds in excess of Mach 1.2 while at full afterburner.

The F-35B can fly for 80 cumulative seconds at Mach 1.2 or 40 seconds at Mach 1.3 without risking damage.

But for both the C and B models, flying at Mach 1.3 over the specified time limits poses the risk of inducing structural damage to the aircraft’s horizontal stabilizer.

And when those timer violations occur, they will result in “degradation of [stealth], damage to [communications, navigation and identification] antennas, and/or significant [horizontal tail damage],” one document explained.

It is infeasible for the Navy or Marine Corps to operate the F-35 against a near-peer threat under such restrictions, the documents acknowledge.
 

Hyperwarp

Captain
Going through my old photos, I could find only one reference to the 180 kN value. But this was before 2015 (2012/2013 ??). In the table below the SF-A thrust is put at 13t (13,000 kg). That would be roughly 127.5 kN. So I think we can assume at least at one point they were targetting the WS-15 to have dry-thrust of >125 kN and afterburning thrust of ~180 kN. Today, this doesn't mean much. We have had little to no updates on the progress of the WS-15. Our member 'Maya' said it would take at least 10 years for a fully completed WS-15 (not just the core) to be tested. This was back in 2008/2009. So we have now reached the 10-year mark. Fingers crossed!


 

Deino

Lieutenant General
Staff member
Super Moderator
Guys ... can we stay on topic - since now we are a bit far off with this strange discussion on the F135's maximum thrust and other Chinese engines - and as far as i know there is a dedicated J-20 thread for aerodynamics and so on...
 

Xsizor

Junior Member
Registered Member
Going through my old photos, I could find only one reference to the 180 kN value. But this was before 2015 (2012/2013 ??). In the table below the SF-A thrust is put at 13t (13,000 kg). That would be roughly 127.5 kN. So I think we can assume at least at one point they were targetting the WS-15 to have dry-thrust of >125 kN and afterburning thrust of ~180 kN. Today, this doesn't mean much. We have had little to no updates on the progress of the WS-15.
I was about to ask the details of the dry thrust of WS-15.
A quick search throws up figures like 105 kN and would make my forehead wrinkle a bit.
Since super cruise ought to be flight without afterburners, the dry thrust should be significant enough to push the aircraft over the mach speed. We are talking about a heavy fighter here that is a metre longer than the F-22. The values were the "targets" as of 2012.
The 127.5 kN figures need to be confirmed.
 

Tirdent

Junior Member
Registered Member
Yes, we know that under ideal conditions the F135 can reach 220 kN. The J-20 and F-35 should be seen as twins when it comes to engines; the J-20 is currently hobbled by a crap engine, while the F-35 is also hobbled by non-mature engines. The US often tends to just negate aerodynamic disadvantages by increasing thrust; see the P-51s and the history of American aviation up until the present day. While the F-35 may be a crap or mediocre dogfighter today, future thrust increases (10% thrust increase from 190kN to 219kN is essentially resting thrust) will make the F-35 more competent and capable in WVR.
What ideal conditions might those be? That report is just Pratt milking tests which are not directly applicable to the real world for maximum publicity.

Don't confuse triple-red-line (150h endurance run at max. pressure, speed & temperature *simultaneously*, a condition never encountered in real operation) durability testing with the actual capability of the engine in service. The triple-red-line test is specifically designed to wear the engine out at a rate so much faster than in actual service that its TBO interval can be established in "time lapse" on the bench. EVERY engine has yielded higher thrust than it was initially certified for during endurance qualification for this reason.

I think the F110 (or was it the F100?) reached ~160kN during tests in the 1990s, yet about a decade later the highest operational thrust rating (likely including tech insertions that the test engine did not have at the time) was 144kN on the F-16 Block 60. It does demonstrate the aerodynamic ability of the engine to handle the increased mass flow required to hit the higher thrust, but says nothing on whether its mechanical design can ever be sufficiently enhanced to cope with the higher loads and temperatures for acceptable TBO at this rating. It may happen eventually, but more probably some of the potential will forever go untapped.

The Trent XWB-84 for the Airbus A350-900 reached more than the certified thrust of the XWB-97 for the A350-1000 on the test stand - why was the XWB-97 developed at all (and it's far more than just a beefed-up XWB-84, 5% larger core engine, so limited parts commonality)? Because despite its bench testing results the basic engine couldn't handle the higher thrust without intolerably quick deterioration, that's why. Or the GE90 - it's rated for a maximum of 513kN in service but has achieved 569kN during its triple-red-line on the ground (and it was a colder-than-standard day to boot, so higher air density which is also favourable). Now GE says the GE9X may have topped that, despite aiming at a LOWER operational rating than the GE90 at 467kN. You have to view these reports in proper perspective.

As for the P-51, you have that bass-ackwards - when it appeared the Mustang was faster than contemporary Spitfire versions powered by the same Merlin engine, despite being significantly heavier and much longer-ranged. That wasn't magic, it was better aerodynamics (later Spitfire marks overtook the P-51 again, but only because they were fitted with the far more powerful RR Griffon, which did nothing to improve its short legs).
 

Inst

Senior Member
The point of comparison I'm using is more Zeros and Ki-43. The Japanese sacrificed armor because they needed to get the lightest plane they could, the Americans had engines that made it so that they didn't need to sacrifice protection for performance.

I'll also point out that the F135 upgrade/replacement programs call for 10% thrust increases, or the engine would roughly be in line of 210 kN given stated thrust of over 190kN.
 

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