PAK-FA : photos and videos

Indian-Devil · May 21, 2010

kaku said:
No, i think russia want to invade afganistan together(India and Russia) after total withdraw of NATO-ISAF. and also can also called its other allies.

But i think india not sent its army in afganistan because its cost lots of money and india have lots of internal issue.

Why is so. Why Russia will invade Afganistan??? Simply cant stop laughing on the way you have kept these baseless comments.. :rofl:

mohit · May 21, 2010

kaku said:
No, i think russia want to invade afganistan together(India and Russia) after total withdraw of NATO-ISAF. and also can also called its other allies.

But i think india not sent its army in afganistan because its cost lots of money and india have lots of internal issue.

Huh?

Did you wake up on the wrong side of the bed today?

SpArK · May 21, 2010

kaku said:
No, i think russia want to invade afganistan together(India and Russia) after total withdraw of NATO-ISAF. and also can also called its other allies.

But i think india not sent its army in afganistan because its cost lots of money and india have lots of internal issue.

Are u alright?? are u sure you are in the right forum??? :what:

Indiarox · May 21, 2010

kaku said:
No, i think russia want to invade afganistan together(India and Russia) after total withdraw of NATO-ISAF. and also can also called its other allies.

But i think india not sent its army in afganistan because its cost lots of money and india have lots of internal issue.

Said like a true noob

Parashuram1 · May 21, 2010

A.V. said:
south asian media hype 10% true ..........

This is pretty common when it comes to fanboys of military in any country (including countries of South Asia). But I don't think your government would be using that line if you see the number of orders the Indians are placing with your aircraft manufacturers.

From what I read on this posts both from Pakistanis and Indians, the latter were interested earlier in 230 of your Sukhoi fighters. However, since last year, there has been an increased demand of additional 40-50 of same fighters (with perhaps respective technological updates). I used to consider such news gasbags but after this last deal, I have shut my mouth and not criticized Indians.

gaurish · May 21, 2010

kaku said:
No, i think russia want to invade afganistan together(India and Russia) after total withdraw of NATO-ISAF. and also can also called its other allies.

But i think india not sent its army in afganistan because its cost lots of money and india have lots of internal issue.

Y afghanistan dude??? americans cant manage afghanistan do u think Indian & russian will be able to control the territory.... and for what reason they want afghanistan???

gambit · May 22, 2010

gubbi said:
Thanks for the clarification. Another question. Do these play a role something akin to inlet ramps during high AoA? The Sukhoi aircraft do have insane AoA!

Not exactly certain what you mean there. The F-15's and F-14's movable inlet ramps are to slow down supersonic air. Any air flow over them of course will influence the aerodynamics at that time but the FLCS stability augmentation system would deal with that. Angle of attack is created by rear stab deflections, but the higher the AoA, the less lift available for the airfoil, and that include the lifting body as well.

Prior to computerized stability augmentation system, a pilot would have to learn his aircraft's idiosyncrasies manually, if he pulls back on the stick, it is up to him to know his aircraft's pitch limit lest he stall his wings. And if he does stall, it is up to him to know how to recover. There were no AoA probes back then. But with 'angle of attack probes' (keywords image search) we can program the FLCS computer to limit rear stab deflections REGARDLESS of pilot inputs. This is a huge misconception regarding Western fighters where some believe Western fighter designs cannot handle high AoA. These AoA limits are balanced between speed, altitude, pilot input and external loads. The calculations are transparent and designed to avoid pilot induced stall situations. For the Soviet/Russian fighters, those high AoA require exceptional airmanship to handle and recover. They may be available but based upon our investigations and conversations of Soviet trained Eastern European pilots, the airshow high AoA situations are to be avoided. Talk to any pilot and you will find the truth, that none like to approach his aircraft's AoA limits and if the aircraft is designed to prevent him from doing it to himself -- great.

Take a look at the PAK-FA's outline superimposed over the F-22.

I highly suspect the PAK-FA's wide engine spacing, to accommodate 3D thrust vectoring, necessitated the movable leading edge root extension (LERX). The PAK-FA's wing sweep is almost the same as the F-22's. The F-22's wing leading edges has continuous 'slats', which are the front version of trailing edge 'flaps', to increase surface area for lift. The PAK-FA's wing leading edges also does have 'slats' but the designers seem to need more, hence the movable LERX. The wings themselves are comparable to the F-22's wings in terms of surface area:

Sukhoi PAK FA - Wikipedia, the free encyclopedia

Wing area: 78.8 m2 (848.1 ft2)

Aerospaceweb.org | Aircraft Museum - F-22 Raptor

Wing Area 838 ft² (78.0 m²)

Not that much different for a clearly larger aircraft -- fuselage-wise. So it looks to me that RCS requirements forced those wing surface area and the desire to match the F-22 maneuverability -- movable LERX -- which remains to be seen if they are detrimental to the low RCS requirements. But then again, it could be argued that because of the movable LERX, the PAK-FA is not in the same RCS class as the F-22 or F-35. Way too early to tell.

gubbi · May 22, 2010

gambit said:
Not exactly certain what you mean there. The F-15's and F-14's movable inlet ramps are to slow down supersonic air. Any air flow over them of course will influence the aerodynamics at that time but the FLCS stability augmentation system would deal with that. Angle of attack is created by rear stab deflections, but the higher the AoA, the less lift available for the airfoil, and that include the lifting body as well.

Prior to computerized stability augmentation system, a pilot would have to learn his aircraft's idiosyncrasies manually, if he pulls back on the stick, it is up to him to know his aircraft's pitch limit lest he stall his wings. And if he does stall, it is up to him to know how to recover. There were no AoA probes back then. But with 'angle of attack probes' (keywords image search) we can program the FLCS computer to limit rear stab deflections REGARDLESS of pilot inputs. This is a huge misconception regarding Western fighters where some believe Western fighter designs cannot handle high AoA. These AoA limits are balanced between speed, altitude, pilot input and external loads. The calculations are transparent and designed to avoid pilot induced stall situations. For the Soviet/Russian fighters, those high AoA require exceptional airmanship to handle and recover. They may be available but based upon our investigations and conversations of Soviet trained Eastern European pilots, the airshow high AoA situations are to be avoided. Talk to any pilot and you will find the truth, that none like to approach his aircraft's AoA limits and if the aircraft is designed to prevent him from doing it to himself -- great.

Thanks for the explanation. I am what you call a greenhorn/noob. So excuse my ignorance.
Correct me if I am wrong here, but at high AoA, the airflow to the engine is not adequate and hence the inlet shape plays an important part? I was thinking that may be the LERX on PAK-FA would be to deflect airflow into the intake at a high AoA.

Take a look at the PAK-FA's outline superimposed over the F-22.

I highly suspect the PAK-FA's wide engine spacing, to accommodate 3D thrust vectoring, necessitated the movable leading edge root extension (LERX). The PAK-FA's wing sweep is almost the same as the F-22's. The F-22's wing leading edges has continuous 'slats', which are the front version of trailing edge 'flaps', to increase surface area for lift. The PAK-FA's wing leading edges also does have 'slats' but the designers seem to need more, hence the movable LERX. The wings themselves are comparable to the F-22's wings in terms of surface area:

Sukhoi PAK FA - Wikipedia, the free encyclopedia

Aerospaceweb.org | Aircraft Museum - F-22 Raptor

Not that much different for a clearly larger aircraft -- fuselage-wise. So it looks to me that RCS requirements forced those wing surface area and the desire to match the F-22 maneuverability -- movable LERX -- which remains to be seen if they are detrimental to the low RCS requirements. But then again, it could be argued that because of the movable LERX, the PAK-FA is not in the same RCS class as the F-22 or F-35. Way too early to tell.

As you said that the surface area of wings of both aircraft is comparable, but isnt the want of a greater surface area compensated in PAK-FA by the flat underbelly between the widely spaced engines? Like you said in you previous post, these fighters are basically lifting bodies!

marcos98 · May 24, 2010

ptldM3 · May 24, 2010

http://img72.imageshack.us/i/pakfahires4.jpg/

http://img30.imageshack.us/i/pkafas.jpg/

gambit · May 25, 2010

gubbi said:
Thanks for the explanation. I am what you call a greenhorn/noob. So excuse my ignorance.
Correct me if I am wrong here, but at high AoA, the airflow to the engine is not adequate and hence the inlet shape plays an important part? I was thinking that may be the LERX on PAK-FA would be to deflect airflow into the intake at a high AoA.

The 'angle-of-attack' is relative to the direction of the body. Let me put it this way...

The AoA for the above F-15 is: 0. Air is entering the engines just fine. Look at the inlet ramps and you will see they are quite neutral.

gubbi said:
As you said that the surface area of wings of both aircraft is comparable, but isnt the want of a greater surface area compensated in PAK-FA by the flat underbelly between the widely spaced engines? Like you said in you previous post, these fighters are basically lifting bodies!

These aircrafts are more like body-wing blended rather than true lifting bodies.

You need wings in order to make turns like the F-15 above. The PAK-FA's movable LERX are to change the body's upper surface area. Try this NASA educational source for starter...

Effect of Shape on Lift

A body-wing blended design must still obey the aerodynamic laws that governs airfoil.