What modification should be done to 3rd prototype of PAK-FA?

[gambit]

Everyone should take a hard look at the below illustration...

Say that we want to reduce the aircraft's overall RCS. The first thing that must be understood is that an aircraft is a complex body that is made up of many smaller complex bodies, or structures, and each structure is called a 'contributor'.

For the above illustration, it would be a waste of resources if the largest contributorship, that complex corner reflector structure created by the single vertical stabilator and the two horizontal ones that resulted in that huge voltage spike, is not reduced.

This is what a 'corner reflector' look like...

...And such a structure is a big no-no if the goal is to control RCS.

Buoyage Systems Australia Pty. Ltd. :: More Info

Every boat needs a radar reflector.

Experts agree that the best radar reflector is the one that gives the highest radar cross-section and continuous coverage.

Corner reflectors are used for small marine craft safety purposes so large vessels can see these smaller boats. It is not that difficult to look at an aircraft, a car, or even the human body, and find plenty of corner reflectors of varying sizes. But for RCS control as in having the vehicle as small an EM signature as possible, they are to be avoided like the plague. So for the aircraft above, that large voltage spike must be reduced to at least the same level as the other voltage spikes.

For the PAK-FA, we should not expect to see anything that drastic, however, we would not know if there are structures on the aircraft that demands immediate attention until we take isolated EM anechoic chamber measurements, like how the US measure our 'stealth' aircrafts at Benefield => Edwards Air Force Base - Media Search

This is part of the 'balanced stealth' approach where not only do we try to balance out infrared, acoustic, visual, and EM, when it comes to EM, the goal is to focus on the largest contributorship and work our way smaller. Once we have achieve a relatively uniform intensity level from all EM contributors. The really hard work begins where we would work on all contributors at the same time to maintain that reduction level. It make no sense, financial or else, to reduce a contributor to negligible while several other contributors simply cannot be reduced further.

This is why Lockheed engineers laughs so hard at some who would zero in on the F-22's conventional diverter inlets as if somehow the aircraft's RCS have been 'compromised'. Since everything are already contributors, it make evident common sense the 'so what' question: So what if the diverter plate may be the greater RCS contributor than the DSI 'bump'? If everything else on the aircraft cannot be reduced further, what financial sense is it to install the DSI system anyway? But since the F-22's RCS is so low overall, that mean its conventional diverter plate inlet systems are irrelevant and is actually very well designed.

The PAK-FA may have a relatively uniform EM signature overall. We just do not know and Russia is not going public with the true figure.

 

[gambit]

Post 61 is where we attempt to deal with large structures regarding their contributorships. Assume for now that we have mostly succeeded but the aircraft is still above a certain radar threshold.

Grooves are smaller corner reflectors whose constructive interference behaviors are well known. Grooves are created by panels that are frequently accessed, such as landing gear bay and maintenance doors. Since they cannot be eliminated, the goal would be to redirect any possible signals away from the source direction. Hence the 'sawtooth' pattern on these doors. Grooves are also created by fasteners and gouges. Here is an unconfirmed rumor about working on US 'stealth' aircrafts: Maintainers cannot simply tightened screws and leave them as is. Of course a screw must be secured but care must be taken so that the end position of the screw head minimizes the possibility of a radar signal entering the groove and behave as illustrated. If this rumor is true, that should be an indication of how much of a contributorship surface imperfections, intentional or not, can be towards the overall RCS value. And how serious the US take this issue.

 

[Firemaster]

Everyone should take a hard look at the below illustration...

Say that we want to reduce the aircraft's overall RCS. The first thing that must be understood is that an aircraft is a complex body that is made up of many smaller complex bodies, or structures, and each structure is called a 'contributor'.

For the above illustration, it would be a waste of resources if the largest contributorship, that complex corner reflector structure created by the single vertical stabilator and the two horizontal ones that resulted in that huge voltage spike, is not reduced.

This is what a 'corner reflector' look like...

...And such a structure is a big no-no if the goal is to control RCS.

Buoyage Systems Australia Pty. Ltd. :: More Info

Corner reflectors are used for small marine craft safety purposes so large vessels can see these smaller boats. It is not that difficult to look at an aircraft, a car, or even the human body, and find plenty of corner reflectors of varying sizes. But for RCS control as in having the vehicle as small an EM signature as possible, they are to be avoided like the plague. So for the aircraft above, that large voltage spike must be reduced to at least the same level as the other voltage spikes.

For the PAK-FA, we should not expect to see anything that drastic, however, we would not know if there are structures on the aircraft that demands immediate attention until we take isolated EM anechoic chamber measurements, like how the US measure our 'stealth' aircrafts at Benefield => Edwards Air Force Base - Media Search

This is part of the 'balanced stealth' approach where not only do we try to balance out infrared, acoustic, visual, and EM, when it comes to EM, the goal is to focus on the largest contributorship and work our way smaller. Once we have achieve a relatively uniform intensity level from all EM contributors. The really hard work begins where we would work on all contributors at the same time to maintain that reduction level. It make no sense, financial or else, to reduce a contributor to negligible while several other contributors simply cannot be reduced further.

This is why Lockheed engineers laughs so hard at some who would zero in on the F-22's conventional diverter inlets as if somehow the aircraft's RCS have been 'compromised'. Since everything are already contributors, it make evident common sense the 'so what' question: So what if the diverter plate may be the greater RCS contributor than the DSI 'bump'? If everything else on the aircraft cannot be reduced further, what financial sense is it to install the DSI system anyway? But since the F-22's RCS is so low overall, that mean its conventional diverter plate inlet systems are irrelevant and is actually very well designed.

The PAK-FA may have a relatively uniform EM signature overall. We just do not know and Russia is not going public with the true figure.

Highly Informative.
I understood only 90 %

 

[DrSomnath999]

Everyone should take a hard look at the below illustration...

Say that we want to reduce the aircraft's overall RCS. The first thing that must be understood is that an aircraft is a complex body that is made up of many smaller complex bodies, or structures, and each structure is called a 'contributor'.

For the above illustration, it would be a waste of resources if the largest contributorship, that complex corner reflector structure created by the single vertical stabilator and the two horizontal ones that resulted in that huge voltage spike, is not reduced.

This is what a 'corner reflector' look like...

...And such a structure is a big no-no if the goal is to control RCS.

Buoyage Systems Australia Pty. Ltd. :: More Info

Corner reflectors are used for small marine craft safety purposes so large vessels can see these smaller boats. It is not that difficult to look at an aircraft, a car, or even the human body, and find plenty of corner reflectors of varying sizes. But for RCS control as in having the vehicle as small an EM signature as possible, they are to be avoided like the plague. So for the aircraft above, that large voltage spike must be reduced to at least the same level as the other voltage spikes.

For the PAK-FA, we should not expect to see anything that drastic, however, we would not know if there are structures on the aircraft that demands immediate attention until we take isolated EM anechoic chamber measurements, like how the US measure our 'stealth' aircrafts at Benefield => Edwards Air Force Base - Media Search

This is part of the 'balanced stealth' approach where not only do we try to balance out infrared, acoustic, visual, and EM, when it comes to EM, the goal is to focus on the largest contributorship and work our way smaller. Once we have achieve a relatively uniform intensity level from all EM contributors. The really hard work begins where we would work on all contributors at the same time to maintain that reduction level. It make no sense, financial or else, to reduce a contributor to negligible while several other contributors simply cannot be reduced further.

This is why Lockheed engineers laughs so hard at some who would zero in on the F-22's conventional diverter inlets as if somehow the aircraft's RCS have been 'compromised'. Since everything are already contributors, it make evident common sense the 'so what' question: So what if the diverter plate may be the greater RCS contributor than the DSI 'bump'? If everything else on the aircraft cannot be reduced further, what financial sense is it to install the DSI system anyway? But since the F-22's RCS is so low overall, that mean its conventional diverter plate inlet systems are irrelevant and is actually very well designed.

The PAK-FA may have a relatively uniform EM signature overall. We just do not know and Russia is not going public with the true figure.

exactly sir ,very well explained by u ,sir this is the better way of what u explained here above

it should also be noted that a flat plate focuses its backscattering
on a very narrow angular sector, with a high RCS value.
A sphere, by contrast, has a low RCS value which is uniform at all angles.
Thus, on a limited angular sector around the specular direction, spheres
and cylinders give the lowest RCS values. If otherwise, RCS must be kept
low on a wide angular sector, then it is better to use very narrow-beam
shapes such as the flat plate, correctly aimed in order to avoid the specular
flash [7].

are single piece canopies more stealth than two pieces if so what about F-35, B-2 or F-117?

Square trihedral corner reflector Strongest radar return due to triple reflection of incident wave



Right dihedral corner reflector Second strongest radar return due to double reflection of incident wave; decreases from maximum slowly with changing θ and rapidly with changing φ


Flat plate Third strongest radar return due to direct reflection of incident wave; decreases rapidly as incidence angle changes from perpendicular



Right circular cylinder Strong radar return as aspect (&#952 changes, but decreases rapidly as azimuth (&#966 changes

From a frontal view the F-22 is very stealthy

however radars will see the F-22 from angles more like this

still from this view T-50 is very stealthy and is what they will try radars see


A radar looking at the same angle the J-20 and F-22 will have an excellent view of both jets, so you can be sure, they will try radars do not see those angles of J-20 anf F-22

 

[DrSomnath999]

well i think russia are desperate hurry to operationalize Pakfa so they are not giving importance any more design changes ,Instead in pak fa 3rd protype we may expect installation of new x band AESA radar in 3rd protype .well 4th protype would also be built
so lets see can russia do some changes i doubt

 

[RickyBahal]

Is the news about 3rd prototype true?

 

[tvsram1992]

Highly Informative.
I understood only 90 %

I understood remaining 10%

 

[DrSomnath999]

Is the news about 3rd prototype true?

what news ????

 

[Firemaster]

I understood remaining 10%

Hey you mean only 10%

 

[tvsram1992]

Hey you mean only 10%

just kidding

 

[rkapo7]

If you read Russian reports all of the modifications talked about are on the way. Either developed or almost there.
It is not engine turbines that can be seen in the early Photos of the intakes.
They are blockers made of composites probably. They are too far forward to be Turbines.
The intake if not S type is definitely curved. They have to be - they have to curve up and around the wheel arches. Probably up and inwards and then out to the engines. Obvious now from all the photos available from different angles etc. Russian Engineers and Designers are not going to make such a basic mistake as to leave the turbines exposed.
RAM has not been put on the early aircraft. A waste of time at this stage.
It is intended all protrusions be eliminated. The IRST dome etc.
A one piece canopy has been developed and is being tested. [Maybe it has a few problems - does not matter - they don't need it for at least 3-5 years.
The Russians don't waste money just to prove how clever they are. If they have a few older canopies around they will use them up for sure on Prototypes that will in the end probably end up scrap metal.
They don't say much about the IR signature of the engines - they hint they are reducing those by using cooler air flows around the hot inner air - they say its final IR in that area will be better than the F22 from what they know about the F22 - still a secret on the F22 - if they are using a different approach to that used by others of course it will remain secret also. Nobody gives away there secrets and if they are bolt on why would they put it on now and give away there secret years sooner than they need to. Probably they will wait until there ultimate 5th gen engine is ready -2017 they hope.
Just like there L-Band Radars - they are not going to reveal any secrets there if they are more advanced. The first to use them - have they got a secret there/ - who knows? I don't imagine they are putting them on just as an ornament.
In about 10 years we may find out?
The Chairman of there United Aircraft Corporation stated in 2010 the final Pak Fa will look considerably different to the first Prototype. On the prototypes they have made no real attempt to incorporate RAM to any large degree and make them super stealthy. A waste of money and time on the first two being used to test the Airframe and Avionics and Engines etc.
Its ultimate stealth will have been well tested on models etc. and in a laboratory. In line with the normal Russian methods they will simply refine it as they go. Gradual development. I would not mind betting just about every second one of the first production batch to be started in 2013 if they can stay on schedule will be slightly different in small aspects - they will be trying small new ideas even on those. Thats how they do it. Thats how it ends up with most new designs even in the US where they do try to go in with an overall master plan of everything. That has never been the Russian way. They usually take the best from the past and try to keep all its best feature and incorporate all the basic new basic concepts they want into the first prototypes. Don't worry about all the fine detail - it will be a waste if the basic concept has flaws often. With the large airframes they are now use this makes it easy to modify and change things easily as they go.
A problem with the F35 design - there is not much room to move or add extras - overweight already.
It will be very costly to ever change its basic characteristics from what I have read. The F22 is more like the Pak Fa - it has the room and performance etc. to make changes. We now see probably the final nose on the front of the 3rd Pak Fa with the AESA radar fitted. [Unless they find any problems.]
Also the first 2 aircraft were probably fitted with many extra sensors etc. for testing and missing most small refinements.

 

[rkapo7]

If you read Russian reports all of the modifications talked about are on the way. Either developed or almost there.
It is not engine turbines that can be seen in the early Photos of the intakes.
They are blockers made of composites probably. They are too far forward to be Turbines.
The intake if not S type is definitely curved. They have to be - they have to curve up and around the wheel arches. Probably up and inwards and then out to the engines. Obvious now from all the photos available from different angles etc. Russian Engineers and Designers are not going to make such a basic mistake as to leave the turbines exposed.
RAM has not been put on the early aircraft. A waste of time at this stage.
It is intended all protrusions be eliminated. The IRST dome etc.
A one piece canopy has been developed and is being tested. [Maybe it has a few problems - does not matter - they don't need it for at least 3-5 years.
The Russians don't waste money just to prove how clever they are. If they have a few older canopies around they will use them up for sure on Prototypes that will in the end probably end up scrap metal.
They don't say much about the IR signature of the engines - they hint they are reducing those by using cooler air flows around the hot inner air - they say its final IR in that area will be better than the F22 from what they know about the F22 - still a secret on the F22 - if they are using a different approach to that used by others of course it will remain secret also. Nobody gives away there secrets and if they are bolt on why would they put it on now and give away there secret years sooner than they need to. Probably they will wait until there ultimate 5th gen engine is ready -2017 they hope.
Just like there L-Band Radars - they are not going to reveal any secrets there if they are more advanced. The first to use them - have they got a secret there/ - who knows? I don't imagine they are putting them on just as an ornament.
In about 10 years we may find out?
The Chairman of there United Aircraft Corporation stated in 2010 the final Pak Fa will look considerably different to the first Prototype. On the prototypes they have made no real attempt to incorporate RAM to any large degree and make them super stealthy. A waste of money and time on the first two being used to test the Airframe and Avionics and Engines etc.
Its ultimate stealth will have been well tested on models etc. and in a laboratory. In line with the normal Russian methods they will simply refine it as they go. Gradual development. I would not mind betting just about every second one of the first production batch to be started in 2013 if they can stay on schedule will be slightly different in small aspects - they will be trying small new ideas even on those. Thats how they do it. Thats how it ends up with most new designs even in the US where they do try to go in with an overall master plan of everything. That has never been the Russian way. They usually take the best from the past and try to keep all its best feature and incorporate all the basic new basic concepts they want into the first prototypes. Don't worry about all the fine detail - it will be a waste if the basic concept has flaws often. With the large airframes they are now use this makes it easy to modify and change things easily as they go.
A problem with the F35 design - there is not much room to move or add extras - overweight already.
It will be very costly to ever change its basic characteristics from what I have read. The F22 is more like the Pak Fa - it has the room and performance etc. to make changes. We now see probably the final nose on the front of the 3rd Pak Fa with the AESA radar fitted. [Unless they find any problems.]
Also the first 2 aircraft were probably fitted with many extra sensors etc. for testing and missing most small refinements.

 

[DrSomnath999]

If you read Russian reports all of the modifications talked about are on the way. Either developed or almost there.
It is not engine turbines that can be seen in the early Photos of the intakes.
They are blockers made of composites probably. They are too far forward to be Turbines.
The intake if not S type is definitely curved. They have to be - they have to curve up and around the wheel arches. Probably up and inwards and then out to the engines. Obvious now from all the photos available from different angles etc. Russian Engineers and Designers are not going to make such a basic mistake as to leave the turbines exposed.
RAM has not been put on the early aircraft. A waste of time at this stage.
It is intended all protrusions be eliminated. The IRST dome etc.
A one piece canopy has been developed and is being tested. [Maybe it has a few problems - does not matter - they don't need it for at least 3-5 years.
The Russians don't waste money just to prove how clever they are. If they have a few older canopies around they will use them up for sure on Prototypes that will in the end probably end up scrap metal.
They don't say much about the IR signature of the engines - they hint they are reducing those by using cooler air flows around the hot inner air - they say its final IR in that area will be better than the F22 from what they know about the F22 - still a secret on the F22 - if they are using a different approach to that used by others of course it will remain secret also. Nobody gives away there secrets and if they are bolt on why would they put it on now and give away there secret years sooner than they need to. Probably they will wait until there ultimate 5th gen engine is ready -2017 they hope.
Just like there L-Band Radars - they are not going to reveal any secrets there if they are more advanced. The first to use them - have they got a secret there/ - who knows? I don't imagine they are putting them on just as an ornament.
In about 10 years we may find out?
The Chairman of there United Aircraft Corporation stated in 2010 the final Pak Fa will look considerably different to the first Prototype. On the prototypes they have made no real attempt to incorporate RAM to any large degree and make them super stealthy. A waste of money and time on the first two being used to test the Airframe and Avionics and Engines etc.
Its ultimate stealth will have been well tested on models etc. and in a laboratory. In line with the normal Russian methods they will simply refine it as they go. Gradual development. I would not mind betting just about every second one of the first production batch to be started in 2013 if they can stay on schedule will be slightly different in small aspects - they will be trying small new ideas even on those. Thats how they do it. Thats how it ends up with most new designs even in the US where they do try to go in with an overall master plan of everything. That has never been the Russian way. They usually take the best from the past and try to keep all its best feature and incorporate all the basic new basic concepts they want into the first prototypes. Don't worry about all the fine detail - it will be a waste if the basic concept has flaws often. With the large airframes they are now use this makes it easy to modify and change things easily as they go.
A problem with the F35 design - there is not much room to move or add extras - overweight already.
It will be very costly to ever change its basic characteristics from what I have read. The F22 is more like the Pak Fa - it has the room and performance etc. to make changes. We now see probably the final nose on the front of the 3rd Pak Fa with the AESA radar fitted. [Unless they find any problems.]
Also the first 2 aircraft were probably fitted with many extra sensors etc. for testing and missing most small refinements.

sir are u Dr Carlo Kopp of air power australia ?????