Chinese Engine Development

siegecrossbow said:

While everyone is celebrating I’d like to sober everyone up by reminding that the WS-15 development took so long that all of the Chinese military forums are now dead and can’t celebrate the news.

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manqiangrexue said:

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.

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manqiangrexue said:

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.

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siegecrossbow said:

You don't want your fifth gen to fly at Mach 2+ speeds for too long. Heat would cause the RAM to fracture and strip off.

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manqiangrexue said:

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.

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ZeEa5KPul said:

I wouldn't take this information too seriously. That person thinks the H-20 will get WS-20 engines so whatever he has to say can be completely discounted.

Whatever the J-20's max speed with WS-10Cs is, expect the max speed with WS-15 to be around 10% higher.

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siegecrossbow said:

It is confirmed to be Mach 2.0 at Zhuhai Airshow.

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manqiangrexue said:

They seriously declassified the top speed??? By official channel instead of a leak? That's crazy! Why would they do that? I don't know of any benefit or instance where a nation declassified such performance parameters of a top fighter jet that isn't for export and isn't ready to be replaced.

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siegecrossbow said:

You don't want your fifth gen to fly at Mach 2+ speeds for too long. Heat would cause the RAM to fracture and strip off.

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manqiangrexue said:

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.

Click to expand...