PAK-FA takes to the sky!

[Ruag]

The graphic below depicts how the YF-22 evolved dramatically into the F-22 -



Similarly, the PAK-FA too will undergo several changes before it enters service.

 

[Ruag]

Credit Planeman -

 

[krish]

BELLY SIDE LOOKS LIKE YF23

dude no offense is this f22 or f35 prototype or some other different aircraft

 

[xebex]

dude no offense is this f22 or f35 prototype or some other different aircraft

YF23 was a prototype made by Northrop for USAF, but lost the "Adcanced Tactical Figther competiton" to Lockheed's YF-22, which later became the F22 Raptor.

 

[gubbi]

i am referring to similarities i did not say PAK-FA is a copy even if it was i would have been really glad to see it in the skies challenging that dolphin called F-35 indeed the short clip in which the PAK-FA did a lil turn it was amazing. see the video on this thread where the plane turn to right in flight i think..

Roger that.

It indeed was a spectacular sight to see that bird flying! It was worth the wait.
IMHO, PAK-FA when finally inducted into service, would be a serious contender to the F-22!

 

[no_name]

A refreshing new look from the typical su-27 type layout.

 

[Thomas]

Of course there are similarities. However, it is not a copy (if you mean to imply that). If you want a product for a purpose, two people will end up designing a very similar looking product. The same laws of physics apply to the Russians as well.

credit to:Boyko_Borisov

While Russia may have imitated some what the YF-23. As the photo's show the YF-23 incorporates far superior stealth characteristics then the T-50.

 

[gubbi]

While Russia may have imitated some what the YF-23. As the photo's show the YF-23 incorporates far superior stealth characteristics then the T-50.

Can you explain how?
btw, IMHO, PAK-FA share more characteristics with YF-22 than YF-23, and I dont find any imitation. Those pics were for comparison, to point out differences.

 

[ptldM3]

While Russia may have imitated some what the YF-23. As the photo's show the YF-23 incorporates far superior stealth characteristics then the T-50.

Be careful when using the term "superior stealth" Chances are you don't work for Northrop or Sukhoi, so you dont know either of the aircrafts rcs. Granted, the exhaust nossles on the Pakfa are a work in proggress and not very stealthy. However, One has to remember the engines in the pakfa was modified AL-31, 117's, thus we don't know how the final layout will appear, it may have similar nossles to the F-35 or possibly F-22. Other than the engines everything look the way it should. Stealth aircraft come in the form of smooth lines and sharp edges, the Pakfa has both. Also don't let the primered finish fool you, it would look much cleaner/stealthier with a nice coat of RAM. Like i have been saying all along the final product will look different to what we have seen so far.

 

[Luftwaffe]

Thomas whether Russians did or not this thing surely is a big fat challenge to europeans to me atleast european are nervous specially UK..with SU-35/PAK-FA i see RAF to be a dwarf air force with 160 ef-2000 (might increase 1 ore squadron) and around say 138 ordered (might increase to 150) F-35 against PAK-FA number(?) and SU-27/SU-33/SU-35 this is called a real threat and challenge.

I would also like to know is there any future possibilities of Russians offering PAK-FA to France as Russian has bought or is in negotiations for warships from France..could the relations go beyond that..positive feed back would be appreciated.

 

[white_pawn]

Russia tests Vth gen fighter, IAF cheers

India Wants 250 Of Its Own Stealth Fighters

Rajat Pandit | TNN

New Delhi: Even as New Delhi and Moscow are now close to inking the detailed commercial contract for joint production of the fifth-generation fighter aircraft (FGFA), the advanced stealth jet tore into the skies for the first time in Russia on Friday.

The 45-minute maiden flight of the Sukhoi T-50 PAKFA, the first ‘technology demonstrator’ of the FGFA, at the Komsomolsk-on-Amur facility in Siberia was dubbed “successful’’ by Russian officials. “It’s a very encouraging development,’’ said a senior IAF officer. The IAF has reason to cheer since it hopes to induct 250 of these fighters towards its aim of building a true ‘expeditionary’ aerospace force. Fourth-generation fighters typically revolve around multi-role capabilities but the FGFA incorporate stealth technology, composite materials, supercruise, thrust-vectoring and integrated avionics as well.

Though the Russian military-industrial complex is still to recover from its steep downfall after the Soviet Union break-up, the Sukhoi T-50 is being billed as a rival to the American F/A-22 ‘Raptor’, with a unit cost upwards of $140 million. While the Raptor is the only operational FGFA in the world as of now, another one, the F-35 ‘Lightning-II’, is being developed jointly by the US, UK and seven other countries. While the Indian FGFA will be based upon the Sukhoi T-50, it will be built to IAF specifications already handed over to Russia. “The detailed contract is being worked out... It has been in the making for some years now,’’ Hindustan Aeronautics Ltd chief Ashok Nayak told TOI on Friday. Defence minister A K Antony has declared that India wants the development of its FGFA to be over by 2016 to ensure the IAF begins its induction from 2017.

 

[gambit]

Glad you like it, what do you think about the rear? too Flankerish?

The way the exhausts are designed, rear aspect IR and RCS signatures will doubled or even tripled from front. Not good. Dead meat for the Raptor.

Exhaust nozzle convergent coupled with throttle setting control thrust. Everything on a body create its own RCS signature and contribute to the overall RCS value of the body. The convergent-divergent mechanisms of an afterburning turbojet engine are no exceptions, if anything, they are the major RCS creators of the rear aspect.

Take a look at 'iris' style exhaust convergent-divergent nozzle above. It is called 'iris' because the mechanisms works the same way the human eye controls its pupil opening. Look at all the 'feathers' and the gaps between them. Those are corner reflectors and I have explained plenty enough here on how dangerous corner reflectors are to designs intending to be radar LO.

Now look at the F-22 exhaust convergent-divergent mechanisms above. They are simpler in designs and because there are less mechanical 'doodads' such as actuators and 'feathers' the F-22 exhausts are far less RCS contributors than exhausts with the 'iris' convergent-divergent exhausts.

The downside to the F-22's exhaust mechanisms is that it restrict thrust vectoring to 2D, whereas with the 'iris' style, the exhaust TV can be 3D, provided there are sufficient clearance between nozzles, which lead us to the controversial subject of design philosophy, specifically engine placements. Wide area engine placements have advantages and disadvantages. Personally, I have never been a proponent of wide area engine placements. The argument here is that for any reason, from bird ingestion to battle damage to 'Acts of God', in the event of a catastrophic engine failure that result in an engine explosion, the other engine would be somewhat protected. Given the fact that the airframe area between the engines are not empty but contain fuel, wirings and assorted mechanical items, an exploding engine will create enough collateral damage to render the aircraft unflyable anyway.

In the event of a non-exploding engine failure, widely spaced engines will create asymmetric thrust that can send the aircraft into a flat spin, which can be nonrecoverable. The combination here is speed, altitude, attitude and how far apart are the engines that the resulting asymmetric thrust will send the aircraft into a flat spin. An extreme example of asymmetric thrust is the C-17A Engine-Out Compensation System (EOCS) software upgrade to the aircraft's FLCS during take-offs and landings. For EOCS, the critical engine is the most outboard one on each wing if its companion outboard engine on the other wing fail. The software upgrade, upon sensing engine failure, would command a rudder deflection to compensate for the inevitable yaw (lateral) movement by the aircraft.

AOPA Online: AOPA Pilot's "An Invitation to Fly" - Beyond the Private

If one engine fails, for example, asymmetric thrust can cause the airplane to yaw severely. Much of the multiengine flight training curriculum centers on handling such emergency situations.

Fighter aircrafts with multiple engines do not have as wide engine placements as multi-engined transports, nevertheless, asymmetric thrust is still a potential problem for pilot training. The F-14 and F-15 have wider engine placement schemes than the F-18. The wider the engine placements the higher of some energy loss when there is thrust. Any mechanical engineer will tell you that it is better to have thrust as much inline with the main longitudinal axis of the body as possible. It is necessary that thrust be in parallel, but the closer to the central axis, the greater the concentration of their combined thrust to the longitudinal axis, the more energy efficient the TV system. The downside is that the closer the engines are together, there will so little room for movement that 2D vectoring is the only option.

3D vectoring require more complex flight control laws -- IF -- the desire is to automate the thrust vectoring. Automation require the removal of some of the decision making process from the pilot, which is NOT always a positive. The US have done extensive testing on the integration of propulsion into flight control laws, of which the C-17A EOCS is one deployed example, here is the history...

Propulsion Control of Airplanes

In July 1989, the tail engine of the DC-10 of United Airlines Flight 232, enroute from Denver to Minneapolis, sustained a "catastrophic uncontained failure" that created a hail of shrapnel, slicing the hydraulics lines of all three independent systems, leaving the aircraft "marginally controllable" at 37,000 feet. Contrary to the realistically motivated consensus at that time that this flight should have ended in disaster, Captain Al Haynes, with the help of United Captain and DC-10 Flight Instructor Dennis Fitch, quickly improvised a way to keep control of the aircraft by maneuvering the throttles of the remaining wing engines. To the great amazement of aviation officials, the crew managed to bring the aircraft to a crash landing in Sioux City, Iowa, saving the lifes of most of those on board.

NASA - NASA Dryden Fact Sheet - Propulsion Controlled Aircraft

Propulsion Controlled Aircraft is a computer-assisted engine control system that enables a pilot to land a plane safely when its normal control surfaces such as elevators, rudders, and ailerons are disabled. If used on commercial aircraft, PCA and follow on projects could help reduce the number of aircraft accidents.

Essentially...If we have engine failures, there is still a good chance of recovery and survival via flight control surfaces, aka 'dead stick' landing as UA 232 demonstrated...

Deadstick landing - Wikipedia, the free encyclopedia

A deadstick landing, also called a dead-stick landing or forced landing, occurs when an aircraft loses all of its propulsive power and is forced to land. The term is a misnomer, as the flight controls in the majority of aircraft are either fully or partially functional, even with no engine power. So it is not the "stick" (flight control actuator) that is "dead", but rather the engine(s). The term refers to the wooden propeller (the "stick") being stopped in an engine-out setting. The fixed position prop actually creates less drag and increases glide speed.

But what if the aircraft loses some of its flight control surfaces, that is where PCA enabled flight control laws can help. Thrust vectoring works on similar principles as PCA but it is about the incorporation of DELIBERATE off-axis thrust not to recover a damaged aircraft but to radically enhanced its flight regimes. So asymmetric thrust can be exploited to good ends.

The PAK-FA's wide engine placements allows 3D vectoring, however, we do not know the extent of TV automation. Is the pilot allowed individual nozzle vector controls? Now that would remove a lot of mathematical complexity from the flight control laws but would transfer the burden to the pilot. After all, what good in having a feature if you do not know how or allowed to use that feature? Remember UA 232 above where the pilot had to manipulate the throttles himself. This mystery alone begs us to wonder how does Sukhoi view the pilot. Is he a 'killer' first and 'flyer' second? Or would the TV training and operation be so intensive that he would be so busy working the nozzles that he can lose situational awareness and lose the fight?

3D vectoring is best when there is so little aerodynamic forces to exploit that in order to change aircraft attitude, an alternate force is required, this would be at very low airspeed, so low that even if there is any advantage to be gained over the F-22, the F-22 would have to be either battle damaged or at so low an altitude that the F-22 pilot has next to no room to maneuver. The Soviets/Russians do not have a good history of avionics and ergonomics. We knew that even before the Soviet Union collapsed.

Do not be gullible and impressed by that airshow 'cobra' maneuver. It was done with extraordinary airmanship acquired through years of flight experience and natural abilities. That is not how we want our air forces. We want an efficient combination of high flying capabilities and human instincts now. The American philosophy is -- make the aircraft do the flying as much as possible so the pilot can be a 'killer' primary and 'flyer' secondary. When the aircraft exceed maneuvering requirements just through aerodynamic exploitations alone, TV capability is gravy and having 2D only allow some pilot control and some automation without overly complex flight control laws. This is like creating one hundred above average airborne killers in one year instead of ten excellent ones in two years.

Raptors are extinct.

Raptor happens to be vegetarian. Poor thing!!

Raptor is a classification of bird...

Bird of prey - Wikipedia, the free encyclopedia

Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as any bird that hunts other animals. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh.

Dead meat for the Raptor, baby...

 

[hindustan]

Did you read the end?



The aircraft is set to fly next year. :lips: I believe India is funding it secretly or some what and it will acquire it later on. If successful and true. Pakistan is in deep trouble, and looking at far enough i dont see any chances. First it was Su-30 now T-50..

yes you are right pakistan is in deep trouble not because of planes but because of attitude

 

[gubbi]

^^^^@ Gambit.

Very informative post. Excellent explanation even a layman like me can understand.

However I find this T-50 F-22 comparison at this point very stupid for the sole reason that while F-22 is already in service, Sukhoi PAK-FA just had its maiden flight and we all do understand that what we have seen today is/will not be the configuration that goes into series production.

We still dont know the design or the real capabilities of the engines which are to power the PAK-FA. That includes the shape of the exhaust nozzles. IIRC there was a Su-27/35 test bed with 2D TVC with nozzles like those of F-22. We dont know whether that would be incorporated into the new engines.

Another point that many missed here is the placement of the engines on PAK-FA. If you look closely the engines are aligned at an angle to the central axis with the nozzles pointing lightly outwards. Wrt the explanation that you gave regarding wide placement of engines and their effect on flight control, what do you think about this development? Sukhoi engineers probably had a very good reason to design the placement of eninges in that particular manner.

 

[Luftwaffe]

guppi also to remind other members that PAK-FA is the first prototype vs F-22
to others never jump to the conclusion at this point therefore "PAK-FA is a dead meat for F-22 is invalid and foolish statement wise men should know it" pride aside lil americans focus on current issues we all will see the final version won't we?