Geographer
Junior Member
Re: New Generation Fighter
Can someone explain why fixed inlets would be good at one speed and bad at another?
Can someone explain why fixed inlets would be good at one speed and bad at another?
J-20... The New Generation Fighter
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Re: New Generation Fighter
As the speed of an object traveling through air increases the nature of the boundary layer along the surface of that object also changes (particularly as it reaches different speed envelopes, ie sub-, trans-, and supersonic speeds). Though I'm not sure about the particulars, my general understanding is that different inlets are designed to optimize the airflow into the engine at different speed envelopes (which different engines will be designed to perform best at). Anything beyond or below that particular speed envelope will make the engine less efficient, potentially to the point of stalling. Variable inlets get around this by using ramps and internal diverters to control the airflow at different speeds (again primarily to block or control supersonic shockwaves in the airflow). Fixed ramps don't have this luxury, so there's a bit more matching of engine to inlet going on.
Re: New Generation Fighter
Any one have more clear pics of this beast ?
Any one have more clear pics of this beast ?
Re: New Generation Fighter
Another big problem there is that the airflow through the engine has to be subsonic to allow for the combustion to happen. And supersonic airflow would also damage the blades in the compressor stages. So the air flowing into the engine has to be slowed down. So at high speed you need a narrow entry that widens further down, this allows the air slow down by expansion. At slow speeds you need a wide entry so the engine can suck in enough air for operation.
Another big problem there is that the airflow through the engine has to be subsonic to allow for the combustion to happen. And supersonic airflow would also damage the blades in the compressor stages. So the air flowing into the engine has to be slowed down. So at high speed you need a narrow entry that widens further down, this allows the air slow down by expansion. At slow speeds you need a wide entry so the engine can suck in enough air for operation.
MwRYum
Major
Re: New Generation Fighter
Looks like that's it for now. Can't find anything new in the likes of CJDBY either. Some eyewitness account said that some bought SLR to the scene and got their "big gun" confiscated.
If CAC/PLAAF wants to send a message, think they already got what they want. Most of the mainstream media said the first flight would be 2012, though I've heard the report on Phoenix TV that some big shots in the industry claimed the coming year (2011) would be a critical one - does that mean it's going to be 2011?
Looks like that's it for now. Can't find anything new in the likes of CJDBY either. Some eyewitness account said that some bought SLR to the scene and got their "big gun" confiscated.
If CAC/PLAAF wants to send a message, think they already got what they want. Most of the mainstream media said the first flight would be 2012, though I've heard the report on Phoenix TV that some big shots in the industry claimed the coming year (2011) would be a critical one - does that mean it's going to be 2011?
Re: New Generation Fighter
It's also quite wrong. I know I saw he made quite a few revisions as newer pictures surfaced.
It's also quite wrong. I know I saw he made quite a few revisions as newer pictures surfaced.
Re: New Generation Fighter
If one looks at the historical timelines of western aircraft development, first flight comes within a few months of low-speed taxi tests. If we assume the bird is undergoing low-speed taxi tests and the Chinese follow a similar test timeline, it should only be a few months until we see first flight (assuming they don't discover any hiccups with the control laws during high-speed taxi tests).
If one looks at the historical timelines of western aircraft development, first flight comes within a few months of low-speed taxi tests. If we assume the bird is undergoing low-speed taxi tests and the Chinese follow a similar test timeline, it should only be a few months until we see first flight (assuming they don't discover any hiccups with the control laws during high-speed taxi tests).
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