Joke’s on you. No discussion of domestic military matters.
Chinese Engine Development
- Thread starter jackbh
- Start date
Joke’s on you. No discussion of domestic military matters.
by78
General
H-20 will use WS-20 turbofans? That right there is all you need to know about the credibility of this article.
Quickie
Colonel
For security reasons, China does maintenance on the AL-31Fx, the most common Russian fighter jet engine used on J10s and maybe a few older J11s, all by themselves using locally manufactured parts, even improving the engine's lifespans in the process in some of the stories that we heard.
outdated information.
up until 2019 PLAAF wanted to maintain Russian AL-31F along with WS-10 engine but not anymore. AL-31F costly to maintain and advancement in WS-10 changed the entire game plan.
Russian engine equipped fighter jets rapidly down in PLAAF inventory. many old J-11 and J-10 re-engined with WS-10. coz WS-10 production skyrocketed.
PLAAF phasing out AL-31 engine one by one after engine finish its service life. remaining AL-31F fleet will replace very soon with WS-10..
PLAAF want one standard engine due to logistics cost and WS-10 is way easier to maintain.
China already is this year.
Quickie
Colonel
Yes, that was some time back. I was trying to give a historical backdrop of how things were.
manqiangrexue
Brigadier
Something about those numbers doesn't sound right to me, especially if we take @sunnymaxi 's 25,000lbf (~11 tons) dry thrust into the picture. J-20 was specifically designed to do well even with underpowered engines. I can believe that if the dry thrust was around 11 tons, it can reach mach 1.8 in supercruise; 11 tons isn't much less than the wet thrust max of the original AL-31 and Su-27 can get to mach 2.35 on it, so mach 1.8 kinda makes sense, especially to someone who isn't trained in aero-engineering. (Obviously, they're totally different designs but J-20 has decades of aerodynamic research to its advantage though stealth shaping and internal bay requirements to the detriment of kinematic performance compared to the Su-27.) But how to you bump up the thrust to a monstrous 18 tons, making the J-20 the most well-powered fighter jet in the world by far, and end up with a max speed of only just over mach 2.2??? Unless they want to stay very far away from revealing the true speed (highly likely) and just threw 2.2 in there instead of saying, "classifed," I'd say it sounds off. With 2 engines of 18 tons thrust, I'm expecting something like Mach 3, though I'm really not qualified in the field.
The increase in maximum speed (achieved when thrust equals drag) does not scale linearly with engine thrust. To first approximation, drag is proportional to the square of the speed, hence maximum speed goes up as the square root of the increase in thrust. To pull numbers out of a hat, suppose the WS-10C has a thrust of 15 tons and the WS-15 a thrust of 18.5. Max speed would then increase by sqrt(18.5/15) = 1.11. Therefore, if the max speed of the J-20 was M2.2 with WS-10Cs, its M2.45 with WS-15s.
manqiangrexue
Brigadier
I know it's far from linear and not calculable with what we have but I'm just saying it sounds weird compared to other jets. Logically, the J-20, desgined on a premise that it must prioritize high kinematic performance even with underpowered engines, should not have a lower max speed than basically every other twin-engined heavy fighter while also miraculously getting engines that are significantly more powerful than every other twin-engined fighter. Although the caveat to this is that they could have prioritized maneuverability, agility, subsonic and transonic performance at the detriment of max speed since this is one of the less useful envelopes.
They said that the max speed of J-20 is over mach 2.2 with two 18.5 ton WS-15s, not with WS-10C.