J-20... The New Generation Fighter III

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kyanges

Junior Member
Thanks guys, and I do remember discussing these differences, but I thought you were referring to some substantive differrences that I had missed? I think the fact that there appear to be no obvious differences is a good thing and indicative of the overall soundness of the design, I did note on the J-31 thread that the Air Force Magazine had commented on both of these advance tactical prototypes and their likely usages?

Where can I get a glance at this particular piece from Air Force Magazine?
 

kyanges

Junior Member
The Sept 25, 2012 daily report, in a paragraph or so dedicated to the Shenyang bird.

Thanks, I found it. Seems like it's simply repeating one of the views that the J-20 is a strike, and the J-31 is now the air-superiority fighter.

I wish China would just release the physical dimensions of the J-20...
 

T-U-P

The Punisher
Staff member
Super Moderator
Registered Member
I got a question:
What's the advantage of using drag chutes for landing as opposed to something similar to a spoiler? In war times wouldn't having a drag chute slow down the sortie rate? since every plane that landed would need to have a new drag chute installed. Also, someone needs to get rid of the used drag chute off the runway right?
 

plawolf

Lieutenant General
I got a question:
What's the advantage of using drag chutes for landing as opposed to something similar to a spoiler? In war times wouldn't having a drag chute slow down the sortie rate? since every plane that landed would need to have a new drag chute installed. Also, someone needs to get rid of the used drag chute off the runway right?

Well I think the biggest advantage is that a drag chute will stop a fighter in a considerably shorter time/distance compared to using airbrakes.

Drag chutes are pre-packed and just inserted into the housing and fastened, so it seems a relatively straight forward and quick procedure, so I really cannot see that slowing down sortie rates by the slightest.

Since the drag chutes are manually released by the pilot, they can pick a spot/area on the runway to release them where a crew is waiting to collect them, whatever system they have already for collecting used chutes should also work in war time conditions, as even in peace time, you really want to get hold of the chutes asap after they detach for nothing more than practical reasons, as you don't want to be chasing them all over the airfield if it's winding, and the longer you let them drift about, the greater the chance they would snag something and tear.
 

Air Force Brat

Brigadier
Super Moderator
I got a question:
What's the advantage of using drag chutes for landing as opposed to something similar to a spoiler? In war times wouldn't having a drag chute slow down the sortie rate? since every plane that landed would need to have a new drag chute installed. Also, someone needs to get rid of the used drag chute off the runway right?

The drag chute is far more effective simply because it has a larger surface area, and yes someone does have to remove them from the ops area, I imagine, the chutes are packed and ready to go. Their use as noted by some posters is cultural, the Chinese and Russians continuing to use them, and they are very cool, in fact my formative memories of fighters is seeing them pop the chute on roll out, and then watching the chutes collapse, as they were released from the aircraft. F-15s, J-20s, F-18s have fuselage mounted speed brakes which are also quite effective and may be deployed in flight, spoilers the same, where they actually help you slow approach speed, obviously a far more usefull tool all around. Both have their purpose, and it is probly nice to have both.
 

Air Force Brat

Brigadier
Super Moderator
Well I think the biggest advantage is that a drag chute will stop a fighter in a considerably shorter time/distance compared to using airbrakes.

Drag chutes are pre-packed and just inserted into the housing and fastened, so it seems a relatively straight forward and quick procedure, so I really cannot see that slowing down sortie rates by the slightest.

Since the drag chutes are manually released by the pilot, they can pick a spot/area on the runway to release them where a crew is waiting to collect them, whatever system they have already for collecting used chutes should also work in war time conditions, as even in peace time, you really want to get hold of the chutes asap after they detach for nothing more than practical reasons, as you don't want to be chasing them all over the airfield if it's winding, and the longer you let them drift about, the greater the chance they would snag something and tear.

Sorry wolfie, I didn't see your post, we got to the same point, and you made it much better than I.
 

Air Force Brat

Brigadier
Super Moderator
Thanks, I found it. Seems like it's simply repeating one of the views that the J-20 is a strike, and the J-31 is now the air-superiority fighter.

I wish China would just release the physical dimensions of the J-20...

It really probably has more to do with simple physics, engineer and I had this same discussion, Editor Tirpak can likely tell you exactly how long the J-20 is. It has more to do with mass centralization, the J-20 is longer and therefore it will take longer to make pitch transitions all other things being equal, than the F-60 which is more mass centralized. The primary advantage of TVC is quicker pitch response, which will increase turn rate, the only reason it is included on the F-22, and not the J-35. I am NOT trying to relight the dead horse beaters, simply saying that tactically the F-60 also has a niche, and that there are obviously two separate design philosophies at work here. The editors thoughts mirror my own, and that of many in the aviation community.

And NO, I am NOT labeling the J-20 a strike aircraft as the F-35, I don't believe that nonsense, nor should you.
 

Engineer

Major
The Su-27 being a more maneuverable aircraft than the MiG-21 is also a lot bigger, yet you don't call the Su-27 a striker. Size has little correlation with maneuverability. Those authors just say what they want to believe.
 
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Quickie

Colonel
It really probably has more to do with simple physics, engineer and I had this same discussion, Editor Tirpak can likely tell you exactly how long the J-20 is. It has more to do with mass centralization, the J-20 is longer and therefore it will take longer to make pitch transitions all other things being equal, than the F-60 which is more mass centralized. The primary advantage of TVC is quicker pitch response, which will increase turn rate, the only reason it is included on the F-22, and not the J-35. I am NOT trying to relight the dead horse beaters, simply saying that tactically the F-60 also has a niche, and that there are obviously two separate design philosophies at work here. The editors thoughts mirror my own, and that of many in the aviation community.

And NO, I am NOT labeling the J-20 a strike aircraft as the F-35, I don't believe that nonsense, nor should you.

It's also a fact the longer moment of arm of the canards of the J-20 balances out the increase in inertia (Remember here that the comparatively longer J-20 is also thinner so its mass stays about the same and the increase in moment of inertia is due mainly to increase in length). Of course other factors also have to be taken into account, like air resistance and the fact that the J-20 can also use its ruddervators for pitch control and this in combination with the canards can increase the pitch force. In any case, the pitch rate and roll rate of an aircraft has no direct relation to its turn rate, something which I think some of the members here, who I believe has studied aerodynamics (delft, engineer, i.e.), will agree with me.
 
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