Yeah you're right, that photo of the landing gear panel part way up with the blister shape is pretty obvious. Maybe the difference lies in some kind of sensor up front.
J-20 5th Gen Fighter Thread IV (Closed to posting)
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Yeah you're right, that photo of the landing gear panel part way up with the blister shape is pretty obvious. Maybe the difference lies in some kind of sensor up front.
If so, I was wondering why the ACFC openings can't be placed inside the inlet?
plawolf
Lieutenant General
Because you can't have direct airflow in a supersonic inlet.
The airspeed of the incoming airstream needs to be subsonic or else it will cause the engine to flame out. All modern fighter inlets, be it fixed, variable or DSI all manipulates the airflow inside the inlet so that it bounces off of the inlet walls. This creates shock waves which slow the airflow to subsonic speeds when hitting the turbines.
When and where the redirected airflow hits the intake sides will vary depending on the way it is being redirected, which in turn depends on the speed of the aircraft (and hence airflow). As such, it will be near impossible to place an fuel cooling intake within the regular intake where it will get constant airflow.
I am not convinced those meshed openings are for fuel cooling, as you don't need two of them.
Some might scoff, but I still think those openings are to help regular airflow within the intake to work in concert to allow the J20 a much greater range of speeds than traditional DSI would allow.
The entire concept of DSI is to use the shape of the bump to manipulate airflow to achieve the above described dampening effect over a large band of airspeeds. Add two openings would allow the use of positive and negative pressure zones to vary when and where the airflow redirected by the bump first hits the inlet wall, which will cascade down and change the speed of the airflow when it hits the compressor face.
It's basically the same effect as traditional variable intakes, only you would be using pressure zones to shift the airflow rather than metal plates.
If this is really the case, I would love to see the 'experts' who dismissed this idea initially scramble to tell us which western concept the Chinese copied to achieve this innovation.
The massive ones, you mean? On the side of the intake? Well they are grilled, with lots of holes, not for holding optics or sensors.
And they're way to big for a DAS sensor too.
I think j-20s only side looking DAS apertures will be on both sides of the nose, similar to F-35.
I second that opinion for other reasons. The exterior of the inlet wall seems like a constrained and unnatural place to put such vents, since you'd need to work those cooling tunnels around the inlet tunnels.
AssassinsMace
Lieutenant General
I've seen in the Chinese forums suggesting plasma stealth. I know, probably way off but am curious how it works. If it requires an ionized gas enveloping the aircraft, that would be the place to put an ejector. Any other place forward that would get sucked into the intake. The weird filtering of the hexagon could be like a diffuser to spread the gas to cover that side as much as possible.
shen
Senior Member
Because you can't have direct airflow in a supersonic inlet.
The airspeed of the incoming airstream needs to be subsonic or else it will cause the engine to flame out. All modern fighter inlets, be it fixed, variable or DSI all manipulates the airflow inside the inlet so that it bounces off of the inlet walls. This creates shock waves which slow the airflow to subsonic speeds when hitting the turbines.
When and where the redirected airflow hits the intake sides will vary depending on the way it is being redirected, which in turn depends on the speed of the aircraft (and hence airflow). As such, it will be near impossible to place an fuel cooling intake within the regular intake where it will get constant airflow.
I am not convinced those meshed openings are for fuel cooling, as you don't need two of them.
Some might scoff, but I still think those openings are to help regular airflow within the intake to work in concert to allow the J20 a much greater range of speeds than traditional DSI would allow.
The entire concept of DSI is to use the shape of the bump to manipulate airflow to achieve the above described dampening effect over a large band of airspeeds. Add two openings would allow the use of positive and negative pressure zones to vary when and where the airflow redirected by the bump first hits the inlet wall, which will cascade down and change the speed of the airflow when it hits the compressor face.
It's basically the same effect as traditional variable intakes, only you would be using pressure zones to shift the airflow rather than metal plates.
If this is really the case, I would love to see the 'experts' who dismissed this idea initially scramble to tell us which western concept the Chinese copied to achieve this innovation.
Don't Rafales have two intakes?
Snort.
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