J-20 5th Gen Fighter Thread V

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FORBIN

Lieutenant General
Registered Member
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



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

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


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 don't understand your numbers ?
At test bench and full dry thrust, F135 consumes 11.089 kg per hour
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Air Force Brat

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

As others had noted the OVT must be fairly heavily made in order to "live" in the exceeding hot and lightly "constricted" afterburner jet, so yes it does add weight for petals and actuators as you attempt to "redirect" even lightly that extremely high velocity "JET!"....

FORBIN, there is a "very marginal" loss of thrust as you move those "plates" into that hot jet to redirect its flow. Think of putting your finger over the end of a water hose to increase the back pressure, reduce the flow "volume" and as the "back pressure" builds you actually increase the velocity, and reduce the size of the column of water.

that does lead to a very marginal "loss" as your finger "impedes" slightly some of the flow.:cool:
 

Air Force Brat

Brigadier
Super Moderator
"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.

My apologies to "Bernoulli" his theorem actually states that as the diameter is reduced, you have an increase in velocity and a decrease in pressure.

So if our hose had a constriction in the middle, flow though that area would have to be accelerated, and pressure would drop in that local area....once the hose "opened" back up velocity would slow, and pressure would go back up...

For accuracy I should acknowledge that water is not compressible, "air" is compressable, so water is not a perfect medium, but water is helpful to "envision" flow.

The Chinese purchase of the SU-35 will be their first experience with OVT,,,, they are going to love it, the Flanker is a beautiful airplane that thrives with OVT to help it get the "lead out". To be honest as an aft delta, the J-20 would actually benefit more from OVT than the Flanker or Raptor due to the center of lift/center of gravity being farther aft, while the distant coupled canards "lift the nose or drive it down, OVT on the other end would really hasten "pitch transitions" and that is the name of the game in fighter maneuverability.

So China's actual purchase of those SU-35s could be an anomaly, or it could be a harbinger of change, either way, it is a "grabber"....
 

Hyperwarp

Captain
All these kg/hr were supposed to be t/hr right?

No engine can be this efficient.

Or are they kg/hr/kgf?

My mistake. My mistake.
banghead.gif
Kick me in my you know where

it should be " lb/(lbf·hr) " or "kg/(kgf·hr)"

Edit: kg/(daN·hr) is whats given in the CDF post.
 
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