Since when was the F-22’s acceleration specs released? And am I supposed to believe that the Su-35S accelerates better in the supersonic than the F-22?

No. In fact with 50% fuel, Su-27/35 has inferior acceleration to most aircraft types. However when fuelled for equal range its quite possible.

However, if we are talking about precise validity of the graph, none of these numbers are factually correct. Here are some numbers from their respective flight manuals:

F-16: M0,8 to M1,2 -> 34 seconds; time to M1.6 (from M0,8) -> 69 seconds; top speed = M1,91 (which looks correct in the graph)
MiG-29: M0,8 to M1,2 -> 42 seconds; time to M1,6 -> 68 seconds; top speed = M2,25
F/A-18C (with 2x AIM-9+2xAIM-7): M0,8 to M1,2 -> 48 seconds; top speed M1,51
F-5E: M0,8 to 1,2 -> 84 seconds; top speed M1,45 (looks correct)

To add some other known aircraft to these;

F-15E (PW-229, with 4x AIM-7): M0,8 to M1,2 -> 36 seconds; time to M1,6 -> 66 seconds; top speed = M2,1
Su-27S: M0,8 to M1,2 -> 50 seconds; time to M1,6 -> 83 seconds; top speed = ??
MiG-23ML M0,8 to M1,2 -> 48 seconds; time to M1,6 -> 75 seconds; top speed = M1,8
F/A-18E (with 2x AIM-9+2xAIM-7): M0,8 to M1,2 ->~54 seconds top speed = M1,46

As for Su-35; it has same aerodynamics as Su-27, and due to increased fuel capacity, it has same (or similar) T/W with Su-27 at 50% fuel load, so I expect same acceleration from it.

As for F-22, It has same T/W as F-15E and similar aerodynamic layout. Sure it does have some aerodynamic improvements, but it also lacks variable ramps so, IMHO, those values are greatly exeggerated and F-22 fall very close to F-15/16 and may even fall behind them at some speeds.

As for F-35, altough fat and underpowered, its roughly comperable to F-18E in acceleration, so I find 57 second estimate (M0,8 to M1,2) to be valid. However, none of the other aircraft performs as good as the graph claims.

Plane just looks to wide to be a mach 2+ in my totally non expert opinion.

Every other mach 2+ plane seem to follow a longer narrower approach.

Aerodynamics evolved much from 70s,80s. Observe;

F-18:

or F-14 and F-15:
http://birch.family.tripod.com/f14sb8.jpg
http://www.f-16.net/attachments/iaf_f15i_pass_sound_barrier.jpg

And now the F-22, current pinnacle of supersonic performance:

Did you notice the difference? The secondary shockwave forms next to the inlets?? Such mechanisms are used to delay the shock wave formed around the main wing, and reduce the wavedrag while going supersonic. In the old days, having wide wings/body was bad, because more of the airframe would be in supersonic flight and be very draggy. CFD analysis changed all that. In other words, today, you can have wide wings, and have some kind of mechanism to deflect shock wave away from the main wings so they would remain subsonic and cause less drag. Both F-22 and F-35 uses such mechanisms. It was first applied on X-15, then on SR-71 and YF-22 YF-23 and X-35. If T-50 design needs, such mechanism are already implemented into the design.

[ATTACH=CONFIG]221324[/ATTACH]

That doesn’t really answer the question. I wasn’t trying to imply that the Flanker was slow or some sort of inferior aerodynamic design.
Basically the question is: which is the draggier design at say, Mach 1.6 – 2.0, between Su-27 and F-15, between T-50 and F-22?

Such direct comparison is very difficult. Maneuverability demands will determine required CL hence wing profile, and wing area. Having engines seperated to accomodate a lifting area there should have no greater impact than having larger wings. Added bonus is you can have useful empty space to put fuel or equipment in there. (Very much like a flying wing). For a direct statistical comparison, I don’t have sufficently solid data for Su-27, but I have for MiG-29 from its flight manual, and some info for F-15, which is obtained from a soviet information booklet about western aircrafts’ aerodynamics, so may not be 100% accurate, (but I find it to be very close):

MiG-29;

1- Drag coefficient (Cx0) graph with respect to mach number, 2-delta Cx with for payloads 3- Maximal Lift coefficient with respect to mach number:

[ATTACH=CONFIG]221323[/ATTACH]

F-15;
Third graph on the left page (13) is drag coefficient graph with respect to mach number.
First graph on the right page (14) is the Clmax graph with respect to mach number,
Second graph on the right page is the delta cx graph for 4 AIM-9s or 4 AIM-7Fs.

[ATTACH=CONFIG]221322[/ATTACH]

To summarize;
-MiG-29 has higher drag coef than F-15 both at subsonic and supersonic speeds, and it has higher increase of drag coef. at transonic regime.
-MiG-29 has higher lift coefficient than F-15 at all speeds. (max 1,5 vs max 1,1)

As Su-27 has even higher Clmax than MiG-29, expect it to have greater drag coefficient.

Higher Cx, combined with larger airframe, Su-27 is surely draggier than F-15 (at straight line), both at subsonic and supersonic regimes.

However that doesnt lead to a similar comparison between F-22 and T-50. By using different wing profiles, F-22 may even turn out to be both draggy and more maneuverable of the two. We just have no solid numbers about them.

Yeah but this is what I don’t get – in the second pic, the vortex comes off the lerx/chine and over the wing itself,but not the body – and the stabs are in the ‘correct’ position to fend the vortices – which is similar to raptor’s config. I never saw a vortex over the lifting body on t-50. Am I missing something?

What you are seeing is vapor clouds formed due to sudden pressure drop. Seeing less is actually a good thing, and thats what the LEVCONS also provide. Slower the pressure drop = less chance of flow seperation and no vapor clouds. Vapor clouds do form on the T-50s body, however they do so at the same time with wings, which is -again- a good thing. Pressure-drop above the body is just well controlled as it is on the wings.

Thanks. It was a good read. I thought you meant straight line acceleration, not the SEP.

Just to clarify – I didn’t mean frontal projection, but this (I’m sure you will recognize):
[ATTACH=CONFIG]221052[/ATTACH]

Those are the frontal cross sectional areas, graphed in the x axis of the aircraft. Important for area ruling, but not for incompressible aerodynamics.

Yeah, that’s where T-50 comes in. One thing I don’t quite understand – how is it going to deal with the vortices coming off its ‘nose’ over the levcon when stabs are set relatively further apart than on the flanker? Or am I derping…

Judging from the looks of it (I mean I am estimating, i didn’t run an analysis on it), those vortices not something to be dealt with in T-50, but its also desired. At high AOA, on a regular aircraft having a nose with cylindrical cross section causes an phenomenon called vortex shredding, which is a repeated asymetrical flow seperation and vibrates/destabilizes the aircraft on yaw axis:

This is worsened -a lot- by the fact vertical stabs are in the way of this disturbed airflow, and their effectiveness is also reduced (or completely eliminated). So F-16 or Su-27 has verticals at their bottom to stabilize the aircraft at high AOA.

However like I’ve said, PAK-FA uses hexagonal nose cross sections. While it wont prevent flow seperation, it will produce two symetrical vortices which does not destabilize aircraft, Much like Su-34;

As these vortices are symetrical, they are harnessed and this vortices are just like LERX vortex of the wings, they form right above the body, however, to contribute body lift (instead of wing lift).

How much lift compared to total lift is provided by the space between the engines. That space is very huge in volume.

Its added to wing area. Not only the tunnel but any area having the airfoil shapes. Lerx/chines contribute to lift, so they are added too. Su-27 does not really have 62 m2 wings. If you calculate from the blueprints VictorK posted Su-27 has around 37 m2 main wing area and around 11 m2 elevator area. Same for F-22, it does not have 78 m2 wing area. It has 40m2 main wing and 13 m2 elevator area (approximately)

Sorry but… any bird is draggy when pulling high AOA. That’s why it’s called instantaneous. In fact, Su-27 design (as in, any LERX/aerodynamically unstable design) strength is that it requires less alpha per G, therefore inducing less drag while turning. It is easily noticeable in airshows – its control surfaces barely move when entering a turn.
Also, less than impressive acceleration? Compared to what? It may have been a tiny bit more reluctant to go faster than f-15 while already going supersonic, but it has more to do with rather huge bypass ratio of al-31f (fuel economy is more important than supersonic acceleration, I guess) than anything. Yeah, there’s higher wavedrag due to 10% wider wing and the fact that supersonic speeds tend not to like oblique contours, but you also have to remember that Su-27 max cross sectional area/midship is rather tiny for the largest 4th gen aircraft – its cross sections peak at about the same as f-15’s – roughly 3,95 – 4,2 m/sq (depending on your calculating method/errors), while nominal wet thrust is 20% more.

We all know the effects of negative stability. What you say, is equally correct, however this is not exactly what I am talking about. Firstly, it really doesnt matter what frontal cross section is we are not talking about cars here. When aircraft is concerned, the “A” or area in Cd*A for any aircraft is wing or -lifting body- area. Other than inlet area, nothing really contributes to aircrafts drag at high AOA maneuvers. Lift and drag during a maneuver is all related to airfoil shape. Secondly, such inefficiency I am talking is not necessarily a bad thing. This is a slight trade-off for much higher available turn rates. With my lacking english I possibly wont be able to explain it, so I will put some numbers here. For the sake of argument, lets compare F-16 blk50, and Su-27S. Both have same T/W of approx. 1,2 at 50% fuel. lets only talk about subsonic regime, to rule out wavedrag, bypass ratio and inlet related differences, and stick to subsonic aerodynamics. Numbers alone should tell how (and why) is Su-27 is efficient in sustained turns, or inefficient in instantenious ones.

At Sea level M0,5, I will state Gs, and the excess powers of F-16 blk50 and Su-27S respectively.
-1,0g: 630 fps and 590 fps. (this gives an idea how Su-27 design is draggy in straight line, but i will get into that later)
-3,0g: 590 fps and 525 fps (this is the condition where both aircraft pulling 9,2 deg/s turn)
-5,0g: 200 fps and 260 fps (this is the condition where both aircraft pulling 16,1 deg/s turn)
-6,0g -050 fps and 060 fps (F-16 can sustain 19,6 deg/s turn rate, Su-27 can sustain 20,2 deg/s at this speed)
-7,0g -400 fps and -200 fps (22,7 deg/s turn rate)

Despite having similar T/W, Su-27 has less excess power than F-16 (nearly) at all times simply because its more draggy, while this does not translate to maximal horizontal sustained turn rates, it will translate to inferior acceleration and climb performance to F-16 when pulling smaller amount of Gs.

However here is the interesting part: F-16 reaches its lift limit at 7,4Gs by pulling 24 deg/s turn rate. We know the aircraft weight and G load to find lift force, and from that (we know wing area) ClMax; which is 1,56.

At the condition where F-16 maxes out (7,4Gs with approx -500 fps), Su-27 only requires Cl of 1,39. This happens at very comfortable 16,5 degrees AOA, with only -310 fps SEP (I can post a dozen charts here but its too offtopic, I posted them on this forum some time ago you can find them via search) In short, Su-27 excels at sustained turn rate, and also at any turn rate between F-16’s STR and ITR. This is the part you are correct, however this point is hardly a cornering turn for Su-27; As flight manual states, Su-27 is capable of 24 deg AOA to achieve Clmax of 1,85 at M0,5!! This means if Su-27 pilot wants, it can go on and on to pull 9,66Gs at M0,5 to achive 31,44 deg/s turn rate. (You may say its overloading the airframe but we are talking about aerodynamics here) How efficient Su-27 actually is at such ITR? its at -850 fps, which is twice of F-16’s SEP at Clmax. This is the inefficient part I am talking about.

Let me put MiG-29 into my case as well. MiG-29 shares very similar layout to Su-27, but its Clmax is limited to 1.5 due to much thinner airfoil. Result is, it can pull comperable STR to Su-27, but max out at 7,9Gs (which is more comperable to F-16 than Su-27). However, much thinner airfoil means less drag, so MiG-29 has much higher climb rate (345m/s vs 300) and acceleration (600 to 1100 km takes 13,5 seconds in MiG-29 and 15 seconds in Su-27).

Going back to Su-27. Flight manual says, its wings are not stalled at 28 deg AOA. As wings are not stalled, their lift coefficient will keep increasing until 28 deg. Then why is the Clmax occurs at 24 deg AOA? My only explaination is that sudden drop of lift coefficent of the lifting body, due to localised stall.

What I was trying to say in my previous post was this: PAK-FA uses high lift devices to improve lift above its body to both increases lift and delays stall, In a sense, if MiG-29 had used such LEVCON devices, it would have retained same incredible climb and acceleration performance, and we would be seeing cl max to jump to at least 1,7 (assuming linear increase in lift due to delayed stall, excluding the increased cl due to pressure distribution levcon may provide) performance to reach 8,9Gs at M0,5 instead of 7,9. Now imagine what PAK-FA can be if it simply uses the MiG-29 airfoil: (comparing to MiG-29 and Su-27). If we assume pakfa is 23 tons with 50% fuel, PAK-FA will have a T/W of around 1,35 even with current 117 engines. With MiG-29 airfoil, it will have only 10% inferior T/D ratio (as Cd will be same) and 12% better T/W ratio, resulting slightly better (by 1,4%) acceleration and climb rate than MiG-29. With clmax = 1,7 PAK-FA will be able to pull 10,49Gs with its currenly known wing area, which will translate to 34,2 deg/s turn rate @M0,5, 8,7% better than Su-27. Of course, this paragraph is merely a rough estimate, but shows the potential of PAK-FA design. Impressive considering it also has an internal bay within.

P.S. Now that makes me wanna see how big is t-50’s midship.

Probably just as big, but that doesnt matter. Again, cross section means little. If you pull a flat plane with zero theoratical frontal cross section, it will still create drag. (and great amounts of it. Calculation of this drag is a common problem in fluid mechanics) Thats why such objects with long finese Cd is the drag coefficient of upper cross sectional area. *Not front* If you want to compare drag, simply compare wing areas. While they have different Cx, this would be far, far more accurate than comparing their frontal areas. PAK-FA will be draggy, it doesnt matter if its thin as hell. Due to L/D always positive, every single kg in weigh directly translates to induced drag. Heavier aircraft, greater wing area (or greater AOA), greater drag. Its simple as that.

Here you can see Irkut’s Su-30KN is cleared for only 2 KAB1500KRs. The KNs were essentially the developmental forerunners to the Su-30MKI and will have a structurally identical airframe (apart from the canards). It also supports the supposition that the structurally stronger Su-34 & Su-35S can carry only 3 KAB1500s as a load distribution factor.

Impossible for them to have identical airframe, considering Su-30MK has two additional pylons on its wings and 4+ tons greater MTOW. Its very likely that Su-30KN shares its wings with Su-30/27PU/27S.

I’ve posted image of MKI carrying 4xKAB-1500s. KN can carry 2x because of absence of inner pylons.

Here is Su-30MKK with 6x Kh-31s, KN, is likely to carry 4 due to same reason above.

However, IMHO, there is still some inaccuracy in the data. Site says Su-30KN can carry 6 RBK-500 or PB-500 bombs, where Su-27SK flight manual says Su-27 can carry 8, with double MERs on 3 and 4.

Hence (imho) it is highly unlikely that the Su-30MKI can accommodate 2 of the 2.5T BrahMos’ and would explain the strengthening of the MKI airframe for the centreline pylon to accommodate it:

Its ok if we disagree about our opinions. My opinion is, they want to modify the airframe not because it can’t carry in its current state, but because, they require better aircraft performance while carrying BrahMos missile. Obviously going supersonic or pulling some Gs with missile on single pylon would be problematic (difficult to stabilize due to inertia of the long missile) leaving only centerline pylon for the task. And another possibility is the aircraft lack necessary wiring/software to accomodate a centerline guided missile. (I maybe wrong about this one, but has anyone seen MKI carrying a guided A-G munition on centerline?)

How does this defines as war crime? Anyone passing borders illegaly is already violating international law. Mi-17 pilot is warned he is approaching the border, and he crossed the borther nevertheless. If he heard the warning, he deliberately ignored it. If he didn’t, well, its not Turkey’s problem if pilot is incompetent, or his equipment is malfunctioning.