The T-50 (PAK-FA) Thread

[Emu]

Another important point is this:

 

Flat dash intercept for 150nm is accomplished in 16+ minutes with an F-15C, but about 10.5 minutes with an F-22. The F-22 also arrives with fuel to spare.

What's a 'flat dash'?

[GGTharos]

Take-off, specific climb technique to altitude and level supersonic dash to the intercept point. Thus flat. (There maybe a specific altitude-varying acceleration technique involved as well).

[ФрогФут]

However the engines generate so much thrust that it just might not matter.

It is not a matter of thrust. It is a matter of compression shock going into the air duct at some point, i think.

[BronzeBuddha]

It is not a matter of thrust. It is a matter of compression shock going into the air duct at some point, i think.

 

I think what he's saying that the engines are powerful enough such that fixed inlet isn't the limiting factor when it comes to max speed.

 

Still, the T-50 will lightly be more efficient and have considerably longer range compared to the F-22, since it's fuel load is much bigger and it has variable inlets. Insiders also alluded to lighter empty weight and MTOW. It would appear that RCS and VLO is compromised to get these attributes. Like how the T-50 used straighter inlets + radar blocker and the perpendicular joints in the rear fuselage.

[sobek]

It is not a matter of thrust. It is a matter of compression shock going into the air duct at some point, i think.

 

They obviously got it covered or it wouldn't go M2. It wouldn't even go M1.

[Weta43]

They obviously got it covered or it wouldn't go M2. It wouldn't even go M1.

 

??? really not something I know about (happy to be educated about it), but to me common sense says the angle the shock wave is created at varies with speed, and if it's designed so the shockwave doesn't arrive inside the inlet till M2.0, it wouldn't be anywhere near it at M1.5

So

=> not a problem < M2, Problem > M2 ...

[topol-m]

Any new info on whether it's getting changes to its lower and back side, flat nozzles for instance?

[NRG-Vampire]

without offense: have you ever seen flat nozzle on any russian ac ? that's not an f-15 active-atf :D

http://www.yf-23.net/Pics/ATF/MTD/F-15B%20SMTD%20under.jpg

[Namenlos Ein]

without offense: have you ever seen flat nozzle on any russian ac ? that's not an f-15 active-atf

http://www.yf-23.net/Pics/ATF/MTD/F-15B%20SMTD%20under.jpg

An experimental Su-27.

 

http://russianplanes.net/id81659

[NRG-Vampire]

i know those images, but those are actually not nozzles

those are spoilers/elevators/blast governors

noozles are inside of spoiler-boxes

 

and those boxes are ugly as hell :D and easy to do a spoiler/tailstrike with them

Edited July 15, 2014 by NRG-Vampire

[topol-m]

without offense: have you ever seen flat nozzle on any russian ac ? that's not an f-15 active-atf :D

http://www.yf-23.net/Pics/ATF/MTD/F-15B%20SMTD%20under.jpg

 

Dude I know they don't have such now, but this was considered as a possible feature that would increase the stealth characteristics of the aircraft. I'm asking if someone has read recently anything new on the matter, cause I personally haven't. The aircraft might as well stay as it it, but looking at how sometimes prototype aircraft are quite different than the final serial production ones (Su-27 T-10, YF-22...) changes are not to be ruled out.

Also that argument about them not having flat nozzles therefore they can't build ones is invalid IMO, they have quite an experience with engine thrust vectoring so I don't see how that's such a challenge. Have you seen the trust vectoring the R-73 uses? It's a system similar to that of the X-31 or ATD-X. I have no doubts they can put something similar or even Raptor-style nozzles to the PAK-FA, whether they want to is another question.

Without being an expert the aircraft's belly does look like it could get some work too, there seem to be some 90 degree angles there which isn't a good thing.

[NRG-Vampire]

with flat nozzles, probaly they can increase the stealth characteristics but on the other side they will decrease the maneuverability

current t-50 nozzles provide more degrees of freedom

f-22 got only 1d flat nozzles: both moves only same direction, always up-down together

current t-50 nozzles are 3d nozzles: nozzles able to move in opposite direction on the ~vertical axis and moving on the ~horizontal axis able to protect against or can do flat spins of the aircraft

so a non-flat nozzle can provide more maneuverability

[topol-m]

with flat nozzles, probaly they can increase the stealth characteristics but on the other side they will decrease the maneuverability

current t-50 nozzles provide more degrees of freedom

f-22 got only 1d flat nozzles: both moves only same direction, always up-down together

current t-50 nozzles are 3d nozzles: nozzles able to move in opposite direction on the ~vertical axis and moving on the ~horizontal axis able to protect against or can do flat spins of the aircraft

so a non-flat nozzle can provide more maneuverability

 

I know that. They can still keep the 3D thrust vectoring and increase the stealth characteristics by putting three paddle nozzles like in X-31. Having 3D thrust vectoring vs 2D vectoring is also a questionable advantage. It might give you a slight edge in some situations but meh, the concept of stealth in the first place is to stay undetected and fire first avoiding dogfighting, so if a stealthier aircraft enables you to do that you'd probably be willing to sacrifice a bit of your maneuverability.

[NRG-Vampire]

another side effect with flat nozzles: aircrafts with flat (1d or 2d) nozzles need bigger tail(s), just like the f-22

bigger tails keep the aircraft more stable at high speed and at high aoa

but bigger tails means increased side radar cross section as well (specifically as badly)

 

with current rounded 3d nozzles they can use smaller tails (see mig 1.44 too)

 

so t-50 with flat nozzles = less nozzle rcs, but with less stability

---> t-50 needs larger tails keeping the stability = more rcs

---> sum of rcs is the same as before but with less maneuverability

---> t-50 does not need flat nozzles at all

 

and image this little off topic : 2 opposing stealth ac approaching each other head to head

each got better airframe (stealthier) than better radar so they will explore the opponent only in a short distance: then aircraft with better maneuverability will win - in a dogfight

but if

each got better radar than better airframe then it will create a bvr fight...

...later they will need more stealthy airframes ---> induces shorter detection distance ---> dogfight again ---> better maneuverability aircraft win again :D...and so on

 

ps. three paddle nozzles are decreasing the stealth characteristics

all the edges (of paddles) incrasing rcs, same as visible turbine blades

Edited July 15, 2014 by NRG-Vampire

[topol-m]

In that theoretical 1vs1 scenario ^^ the Raptor has the better stealth and the better radar, so guess who's gonna fire first :)

 

ps. three paddle nozzles are decreasing the stealth characteristics

all the edges (of paddles) incrasing rcs, same as visible turbine blades

 

Three paddle nozzles is far from turbine blades in terms of RCS. Following that logic the edges of F-22's nozzles would make it more visible than the conventional round nozzles. Ultimately if you compare the nozzles 3 paddle ones have less area than 1 round nozzle and more than 2 paddle nozzle, so they should be somewhere in the middle in terms of RCS.

Edited July 15, 2014 by topol-m

[NRG-Vampire]

In that theoretical 1vs1 scenario ^^ the Raptor has the better stealth and the better radar, so guess who's gonna fire first :)

 

yep, this is all theoretical :D

it would be better (for the whole world) if the facts should not prove themselves which is more stealthy, modern or better :)

[topol-m]

This will happen sooner or later, it might not be F-22 vs Pak-fa, but seeing how a lot of countries will have 5th gen fighters by 2050 if a war breaks out we will no doubt witness 5th gen vs 5th gen fights. It's just a matter of time.

[Exorcet]

so t-50 with flat nozzles = less nozzle rcs, but with less stability

---> t-50 needs larger tails keeping the stability = more rcs

---> sum of rcs is the same as before but with less maneuverability

---> t-50 does not need flat nozzles at all

Why would the RCS be the same between the larger tails and 2D nozzles? What about the IR signature?

 

and image this little off topic : 2 opposing stealth ac approaching each other head to head

each got better airframe (stealthier) than better radar so they will explore the opponent only in a short distance: then aircraft with better maneuverability will win - in a dogfight

but if

each got better radar than better airframe then it will create a bvr fight...

...later they will need more stealthy airframes ---> induces shorter detection distance ---> dogfight again ---> better maneuverability aircraft win again :D...and so on

 

 

I've always thought this sounded too simple. It's because it's assumed both sides will see each other at the same time and from equal positions, which isn't necessarily true. 5th gen combat will be very much unlike WWII because it's not limited to visual detection, even if beyond visual range detection is hindered by stealth, etc.

 

Maneuverability is important, it's always been important in BVR, but I don't think it will be decisive.

[NOLA]

Wait, so you're implying that the T-50 max speed is lower than the F-22? That's hard to believe. :ermm:

 

Of course it is. That has been known for a long time. And discussed here multiple times.

 

It might actually be. Although I wouldn't expect it to be vastly different, perhaps 200 kph or so. Doesn't matter much either IMO.

 

Depends on your vastly. But it is a fair bit more than "200 kph or so". Whether it matters or not, i don't care about. I like fast planes as much as the next guy, but for me, that is where MiG-31 comes in. Whenever they fix the canopy/windsheild issues that is.

 

Any new info on whether it's getting changes to its lower and back side, flat nozzles for instance?

 

If anything everything points to them not going flat nozzle route. I have even read than nozzle from 117/177S will be used on Izd.30. Source seemed thrust able, but we will see.

 

without offense: have you ever seen flat nozzle on any russian ac ? that's not an f-15 active-atf :D

http://www.yf-23.net/Pics/ATF/MTD/F-15B%20SMTD%20under.jpg

 

When you are ignorant, at the very least don't be arrogant about it.

[topol-m]

If anything everything points to them not going flat nozzle route. I have even read than nozzle from 117/177S will be used on Izd.30. Source seemed thrust able, but we will see.

 

Alright that's what I was looking for, thanks for the info.

[Isenhill]

Так на испытаниях этой весной при полной загрузке топливом и массагабаритными макетами вооружений 4й борт взлетел с 310 метров, достиг крейсерской скорости 2135кмч и максимальной 2610кмч, при этом был еще потенциал по разгону, а так же забрался на 24300 метров - дальше не пустили.

 

This spring fully loaded with fuel and dummy weapons 4th board took off from the 310 meters, has reached cruising speed of 2135 km/h and maximum speed of 2610km/h, there were also potential for more, and also climbed to 24,300 meters - wasn't allowed higher.

 

From radioscanners who are pretty legit.

[NOLA]

Oooooooold info. Apparently originally from radio scanners yes, but the first place i have seen it on was in sdelanounas blog/news site comments. So impossible to verify for sure. What is your source for the quote?

[Isenhill]

http://www.paralay.com/pakfa/pakfa.html

 

Seems like a good source for T-50 info.

 

The given altitude reflects the goal of breaking an area of coverage of air defense Patriot PAC3 MIM-104F Flight altitude 79,500 feet (24,200 m).

Edited July 19, 2014 by Isenhill

[ФрогФут]

Paralay is the database of all rumors and fantasies. There are some real notes, but they drown in the madness of fantasies.

[BronzeBuddha]

From radioscanners who are pretty legit.

 

Given that the T-50 has only started external weapons carriage tests earlier this year, I find the claim regarding the dummy weapons part to be rather suspect.

 

Also, considering that the Indian Air Force thinks that the current T-50 with Izd.117 engines are underpowered, I have a difficult time believing the speed claims. Remember, the new Izd.30 engines won't be out until almost 2020.

Edited July 22, 2014 by BronzeBuddha