J-20 5th Gen Fighter Thread V

[Hyperwarp]

I dug through the CDF engine thread. It seem the WS-15 prototype in 2013 bench tests had reached,

Max Thrust in Afterburner - 161.865 kN
Max Thrust Dry - 105.220 kN

The ~162 kN in AB is slightly higher than the official value of 156 kN for the F119 (Unofficially the F119 thrust is said to be much higher.). But the 105 kN dry thrust of the WS-15 prototype is lower than the F119. F119 dry thrust is said to be around 115 kN.

The final production version of the WS-15 will have to improve on the dry thrust as it is what matters for supercruise.

 

[Air Force Brat]

NO

I have also seen the source that says that flat nozzles trade off 14-17% thrust for stealth. I don't see why it wouldn't reduce thrust when you force round airflow into a rectangular slit. I re-tracked the article down. The source is dubious, but the writing seems very professional and the article is in general very well-supported by citations. Here it is:

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I have also seen one source say that the engineers at Lockmart were able to reduce that supposed loss to an acceptable number.

thanks for naming your source and "coming clean", and I mean this very sincerely, I really do appreciate it. I don't know what LockMart/Pratt & Whitney list as the "straight scoop", but I promise you it is not 17% nor is it 10%, I would range it from 3 to 7%. The total loss would actually be more honestly reflected if we knew the total nozzle area of the rectangular nozzles as opposed to round.

"Bernoulli's Theorem" states that as the diameter of the tube is increased, flow velocity increases with a substantial "drop" in pressure! This would actually increase the exhaust gas velocity, allowing the OVT to substantially increase the velocity and force of the directed exhaust jets to push the tail of the aircraft either up or down, dramatically increasing the pitch rate, it is also possible to trim the aircraft at supersonic speeds with the OVT resulting in far less "trim drag" at supersonic speeds!

Furthermore, when the F-22 was actually introduced and "rolled out" at airshows across the country, the one are that was shielded and had a guard posted were the "Nozzles, OVT actuators/etc. No photographs of the nozzles were allowed, period!

and "don't believe everything you read on the internet", let history and common sense steer you toward the truth, you will never be very far off.

 

[Air Force Brat]

I dug through the CDF engine thread. It seem the WS-15 prototype in 2013 bench tests had reached,

Max Thrust in Afterburner - 161.865 kN
Max Thrust Dry - 105.220 kN

The ~162 kN in AB is slightly higher than the official value of 156 kN for the F119 (Unofficially the F119 thrust is said to be much higher.). But the 105 kN dry thrust of the WS-15 prototype is lower than the F119. F119 dry thrust is said to be around 115 kN.

The final production version of the WS-15 will have to improve on the dry thrust as it is what matters for supercruise.

There you go, and I am much more inclined to believe this much more accurate and realistic "expectation".

 

[Inst]

Sorry, it was late. But my point isn't that the flat nozzles mean that the F119's actual thrust is lower than rated thrust, but rather that the nozzle choice reduces rated thrust and increases weight, but decreases RCS and IR emissions. That said, few aircraft have the same level of all-aspect stealth the F-22 has, and the design choice gives the F-22 a powerful versatility.

 

[Air Force Brat]

Sorry, it was late. But my point isn't that the flat nozzles mean that the F119's actual thrust is lower than rated thrust, but rather that the nozzle choice reduces rated thrust and increases weight, but decreases RCS and IR emissions. That said, few aircraft have the same level of all-aspect stealth the F-22 has, and the design choice gives the F-22 a powerful versatility.

No problem, and I certainly don't have a problem with any of this, as you noted about your source you had some doubts, so in the future if you would note that, we could "weigh" the sources credibility, as it is, you've come a long way here toward becoming a much more reliable source yourself, and thanks for being honest. In the end, we may all end up being off or even flat wrong, but honest efforts to produce honest assessments will likely put us in the neighborhood of the truth.

As I have noted in the past the J-20 does perform very well, and like everyone else here I can't wait to see their Chinese engine, and look forward to the J-20 getting a healthy performance boost.

 

[Hyperwarp]

Regarding those WS-15 bench test values,

Here is the CDF post -

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Translation -

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I don't know about the reliability, so don't sue me,

Comparing the F119, F135, WS15

*Max thrust (A/B)
F119 : >156 kN
F135: ~190 kN
WS15: ~162 kN

*Max thrust (Dry)
F119: ~115 kN
F135: 125 kN
WS15: ~105 kN

*Fuel consumption (A/B)
F119: 0.99 kg/hr (aircraftenginedesign.com/TableB2.html)
F135: N/A
WS15: 2.02 kg/hr

*Fuel consumption (Intermediate)
F119: N/A
F135: N/A
WS15: 0.665 kg/hr

*Diameter
F119: 1.20 m
F135: 1.17 m
WS15: 1.02 m

*Length
F119: 5.16 m
F135: 5.59 m
WS15: 5.05 m

*Weight
F119: 1800 kg
F135: 1700 kg
WS15: 1862 kg

F135 is ahead by quite a margin. Yo AFB, Is the weight difference with F119 due the TVC nozzles? F-135 is 100 kg lighter than the F119. WS15 has to improve its dry thrust and fuel consumption.

 

[latenlazy]

[

Regarding those WS-15 bench test values,

Here is the CDF post -

Please, Log in or Register to view URLs content!

Translation -

Please, Log in or Register to view URLs content!

I don't know about the reliability, so don't sue me,

Comparing the F119, F135, WS15

*Max thrust (A/B)
F119 : >156 kN
F135: ~190 kN
WS15: ~162 kN

*Max thrust (Dry)
F119: ~115 kN
F135: 125 kN
WS15: ~105 kN

*Fuel consumption (A/B)
F119: 0.99 kg/hr (aircraftenginedesign.com/TableB2.html)
F135: N/A
WS15: 2.02 kg/hr

*Fuel consumption (Intermediate)
F119: N/A
F135: N/A
WS15: 0.665 kg/hr

*Diameter
F119: 1.20 m
F135: 1.17 m
WS15: 1.02 m

*Length
F119: 5.16 m
F135: 5.59 m
WS15: 5.05 m

*Weight
F119: 1800 kg
F135: 1700 kg
WS15: 1862 kg

F135 is ahead by quite a margin. Yo AFB, Is the weight difference with F119 due the TVC nozzles? F-135 is 100 kg lighter than the F119. WS15 has to improve its dry thrust and fuel consumption.

I'd be extremely skeptical of that article. Some of its claims, like the STVOL fighter, did not check out.

 

[Blitzo]

[

I'd be extremely skeptical of that article. Some of its claims, like the STVOL fighter, did not check out.

I agree... I think anything with the numbers of that kind of specificty should prompt significant skepticism

 

[latenlazy]

I agree... I think anything with the numbers of that kind of specificty should prompt significant skepticism

Funny I only *just* did this, but I think we've found the original source of the information. Based on this blog entry, it's Russian.

Please, Log in or Register to view URLs content!

 

[FORBIN]

NO

thanks for naming your source and "coming clean", and I mean this very sincerely, I really do appreciate it. I don't know what LockMart/Pratt & Whitney list as the "straight scoop", but I promise you it is not 17% nor is it 10%, I would range it from 3 to 7%. The total loss would actually be more honestly reflected if we knew the total nozzle area of the rectangular nozzles as opposed to round.

"Bernoulli's Theorem" states that as the diameter of the tube is increased, flow velocity increases with a substantial "drop" in pressure! This would actually increase the exhaust gas velocity, allowing the OVT to substantially increase the velocity and force of the directed exhaust jets to push the tail of the aircraft either up or down, dramatically increasing the pitch rate, it is also possible to trim the aircraft at supersonic speeds with the OVT resulting in far less "trim drag" at supersonic speeds!

Furthermore, when the F-22 was actually introduced and "rolled out" at airshows across the country, the one are that was shielded and had a guard posted were the "Nozzles, OVT actuators/etc. No photographs of the nozzles were allowed, period!

and "don't believe everything you read on the internet", let history and common sense steer you toward the truth, you will never be very far off.

Can you help a guy not good in engine matter
Fot what exact reason the power is lower with a vector thrust reactor ?