Ask anything Thread (Air Force)

Equation

Lieutenant General
The question hasn't changed. Do you know whether the J-20 has launched weapons from its internal bay while travelling at supersonic speed? Deploying weapons externally is different from launching from internal bays. One can't assume is business as usual until is proven.

It's actually not always good logic to assume that something is negative unless you see proof that it is positive; the safest assumption is what is the norm and that is assumed unless there is evidence otherwise. For example, if you've never seen your coworker eat, the assumption should not be that he doesn't eat. There is no modern fighter (not in China or the world) that is incapable of launching weapons at supersonic speeds so to assume that of the J-20 actually requires more evidence than to assume that it can. If we were to follow your logic, we would have to assume that J-20 doesn't have a working ejection mechanism because we've never seen a pilot eject from it before.
 

Blitzo

Lieutenant General
Staff member
Super Moderator
Registered Member
It is not business as usual because the drag coefficient is different between designs. For example between an F-15E and a F-16C.

View attachment 52907

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Further more the aerodynamic forces are different depending on speed.

... Yes, all aircraft are unique in terms of how their aerodynamics interact and what that means for their overall kinematic properties.
That goes without saying.

However that does nothing to support your argument that we it is reasonable to believe as the null that a 5th generation fighter was designed in a manner whereby it is not capable of supersonic deployment of weapons from its internal weapons bay.



The only reasonable explanation I can come up with to rationalize your position is if you truly believe that supersonic weapons deployment from an internal weapons bay for a 5th generation fighter is not among the most basic kinematic/aerodynamic requirements for such platforms, but instead believe it to be something unique or exceptional.
 

Brumby

Major
It's actually not always good logic to assume that something is negative unless you see proof that it is positive; the safest assumption is what is the norm and that is assumed unless there is evidence otherwise. For example, if you've never seen your coworker eat, the assumption should not be that he doesn't eat. There is no modern fighter (not in China or the world) that is incapable of launching weapons at supersonic speeds so to assume that of the J-20 actually requires more evidence than to assume that it can. If we were to follow your logic, we would have to assume that J-20 doesn't have a working ejection mechanism because we've never seen a pilot eject from it before.

How do you think the F-35 program found out that they have ejection issues without actually undergoing a testing regime? It is not a positive or negative thing. I was just asking whether there was evidence of testing. If there isn't any then there isn't any. Not a big deal.
 

Brumby

Major
My belief regarding J-20's ability to launch weapons from its internal weapons bay at supersonic speed is similar to my belief that J-20 has an AESA radar,
Btw, the US DOD in their May 2019 report actually stated that China is having difficulty with its radar The wording seems to sjuggest that it is associated with the J-20.
 

Blitzo

Lieutenant General
Staff member
Super Moderator
Registered Member
Btw, the US DOD in their May 2019 report actually stated that China is having difficulty with its radar The wording seems to sjuggest that it is associated with the J-20.

The DoD report says lots of things. Some are more credible than others, while some are of little relevance at all.

There's enough of a history of DoD reports to compare with information we have had in the past, to be able to judge it.


In any case, it is entirely reasonable for us to expect supersonic deployment of weapons from an internal weapons bay to be a very baseline requirement for a 5th gen fighter.
 
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Equation

Lieutenant General
Btw, the US DOD in their May 2019 report actually stated that China is having difficulty with its radar The wording seems to sjuggest that it is associated with the J-20.
Quote it with a link and let's all have a look.

Right off the bat, my initial thoughts are

1. What does the US DOD know about China's radar efforts?
2. If they knew anything, it would have to be from espionage; is it is smart to publish the results of espionage to alert your rival? 3. "Having difficulty" can mean a wide array of things, ranging from being unable to make it work at all to facing challenges making an already superior design leapfrog its rivals generationally.
 

Brumby

Major
... Yes, all aircraft are unique in terms of how their aerodynamics interact and what that means for their overall kinematic properties.
That goes without saying.

However that does nothing to support your argument that we it is reasonable to believe as the null that a 5th generation fighter was designed in a manner whereby it is not capable of supersonic deployment of weapons from its internal weapons bay.



The only reasonable explanation I can come up with to rationalize your position is if you truly believe that supersonic weapons deployment from an internal weapons bay for a 5th generation fighter is not among the most basic kinematic/aerodynamic requirements for such platforms, but instead believe it to be something unique or exceptional.

As I have already stated the aerodynamic forces arising from compressibility changes with speed.
When flow velocities reach sonic speeds at some locations on an airplane (such as the area of maximum
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on the wing), further acceleration will result in the onset of compressibility effects such as
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formation, drag increase,
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,
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, and
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difficulties. Subsonic flow principles are invalid at all speeds above this point.
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upload_2019-7-8_18-58-43.png
When the weapons bay door open besides drag it has an airflow effect. The effects cannot be assumed to be business as usual when we are talking about weapons separation at supersonic speed because compressibility kicks in.

An article on weapons separation that did not go so well.
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