Russian Su-57 Aircraft Thread (PAK-FA and IAF FGFA)

b787

b787

Captain
FORBIN said:
First i don' t means PAK-FA is bad for stealth but less good than F-22/35 it is completely different...


F-22 also and the blocker removes air not good for reactor ?

Also the tunnel between the reactors is not excellent for stealth marginale but it is a break that can constitute a " brilliant point " for a radar.

Why with PAK-FA Russia have build a fighter using Su-27 style ( especialy part under the fuselage ) a solution more simple for build a fighter based on one existing ?
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2.4.4 Short, Aggressive Serpentine Inlets Propulsion airframe integration considerations drive the current research focus towards shorter serpentine inlets with an aggressive centerline offset [30]. BLI embedded engine systems are so highly integrated with the airframe that inlet size becomes a dominant factor in the overall aircraft configuration. Longer S-ducts succeed in avoiding significant losses and AIP distortions as a result of gentler offset and flow turning. Low-distortion serpentine inlets can be designed when sufficient length is available, i.e. an L/D > 2.5. However, inlet length is a significant challenge for propulsion airframe integration. Long inlets significantly increase the size and weight of the overall system and limit vehicle performance [14]. Longer ducts result in a large engine overhang from the trailing edge of the airframe, increasing exposed wetted surface area. This overhang results in weight and drag increases. In one study, a drag benefit from reduced ram of 6.85% was observed. The duct was long enough to produce low amounts of distortion and total pressure loss, resulting in minimal effects on engine performance. However, due to the large amount of overhang, the net effect resulted in a 3.1% increase in fuel burn [10].
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this can basically answer your question
 
Engineer

Engineer

Major
FORBIN said:
First i don' t means PAK-FA is bad for stealth but less good than F-22/35 it is completely different...
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In the context of 5-th generation fighter (using USA and Russia classification), PAKFA is bad for stealth. There is no need to not say the truth to avoid hurt feelings.

FORBIN said:
F-22 also and the blocker removes air not good for reactor ?
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Yes, the blocker causes turbulence that can hurt the efficiency of engine.

FORBIN said:
Also the tunnel between the reactors is not excellent for stealth marginale but it is a break that can constitute a " brilliant point " for a radar.
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Correct. Any discontinuity is a source of radar return.

FORBIN said:
Why with PAK-FA Russia have build a fighter using Su-27 style ( especialy part under the fuselage ) a solution more simple for build a fighter based on one existing ?
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Correct. A true 5-th generation fighter requires a lot of new engineering, which requires a lot of time and investment, the very things that Russia lacks post Soviet collapse.
 
FORBIN

FORBIN

Lieutenant General
Registered Member
Engineer said:
In the context of 5-th generation fighter (using USA and Russia classification), PAKFA is bad for stealth. There is no need to not say the truth to avoid hurt feelings.


Yes, the blocker restricts air and hurts the efficiency of engine.


Correct. Any discontinuity is a source of radar return.


Correct. A true 5-th generation fighter requires a lot of new engineering, which requires a lot of time and investment, the very things that Russia lacks post Soviet collapse.
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There is no need to not say the truth to avoid hurt feelings.
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You can say me at just reasons Rafale is not good for a thing it is not a problem, i am not a chauvinist and it is not good to be...

We are agree :) but the true is the true interesting to know things and i am not here for do big propaganda for F-22/35 but i think he get a design in general more efficient, also USA have build 4 stealth aircrafts since 40 years and surely it help much also for RAM coating it is certain they have more experience...

So what is not good for PAK FA stealth tunnel, nozzles others ?
 
Engineer

Engineer

Major
Equation said:
Yes land radars has improved, but I don't know about radars on jets has the same capability as the ground stealth detecting radars....at least not yet.
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Radars on aircraft use X-band, very short wavelength, so as to provide good resolution for targeting. Anti-stealth radars use VHF, longer wavelength, to exploit physical limitation on stealth shaping. Their requirements for operation are mutually exclusive.
 
Engineer

Engineer

Major
FORBIN said:
You can say me at just reasons Rafale is not good for a thing it is not a problem, i am not a chauvinist and it is not good to be...
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If a Su-27 with radar reduction modification is a 5-th generation fighter, then Rafale with radar reduction features could be called a 5-th generation fighter, right? ;)
Mc8qdoG.jpg
 
F

florin

Just Hatched
Registered Member
What you see is not the surface of the engines but nacelles, structures which contains the engines,a typical russian approach..
 
b787

b787

Captain
Carbon Ghosts': How Coal Plastic Will Help Russian Planes to Dodge Enemy Radar
© Sputnik/ Alexey Filippov
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13:37 29.07.2017(updated 18:44 29.07.2017)Get short URL
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4504620
Composite materials are all the rage today with Russia’s fifth-generation T-50 fighters and, Ka-52 and Ka-62 helicopters making extensive use of polymeric carbon plastics and other high-strength materials, rendering them virtually invisible to enemy radar. Sputnik looked at the way composites can help planes fly better and dodge enemy radar.




© SPUTNIK/ VALERIY MELNIKOV
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The use of carbon-plastic composites, which are lighter than duralumin, titanal and other alloys used in aviation construction, enabled Russian engineers to make the
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just as undetectable by radar as the US F-22 Raptor stealth fighter.


With 70 percent of the T-50’s airframe consisting of composite materials, its developers say that the effective area of the plane’s reflecting surface is just 0.5 square meters. For comparison, in the heavy "metal" SU-30MKI fighter this indicator is 40 times higher and is equal to 20 square meters.

Figuratively speaking, the T-50 is seen on a radar screen as a tiny 50 cm x 100 cm “spot.”



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The T-50’s designer, Alexander Davidenko, told Zvezda TV that due to the use of composites the aircraft has four times fewer parts compared to the Su-27, weighs less and is easier to mass produce.

Composite and radio-absorbing materials will also find extensive use in Russia’s new
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strategic bomber. Designed as a “flying wing,” just like the US B2 Spirit strategic bomber, the PAK DA will be much less visible to radar than its American counterpart.


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Ka-62
Meanwhile, the aircraft factory in Ulan-Ude in eastern Russia has completed flight tests of the new regional TVS-2-DTS plane, almost entirely built from composite materials.

The use of composite materials dramatically reduces a plane’s visibility, as electromagnetic signals are not reflected from carbon fiber surfaces and passing through them or getting absorbed.

As a result all a radar operator sees on his screen is blank space.



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The reduction in visibility is also ensured by the irregular geometrical shape of the plane’s surface, which is simpler to “mold” from carbon plastic than from metal.
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