@TomcatViP:

Frontal section: if you mean the total projected area of the fuselage as a mean to estimate the drag of the airframe, as it was discussed thousand of times here, you have more chance to fall off the real value than to get a proper estimation. here is an exemple of how non-intuitive drag estimation is :

No picture appeared, sorry

Drag is proportional to A and Cd. At a given speed the rest of factors cannot be managed, so cross sectional area is a key issue. No wonder old planes with much weaker engines were extremely thin.

Finesse ratio is certainly not one good parameter to estimate the drag. For exemple the bulky F-4 Phantom outspeed the pointy X-3 by far that compare even poorly with the F-100!

My bad, fineness ratio. Wave drag is the dominant component of drag at transonic and supersonic speeds and scales as the square of the second derivative of the area distribution. So, the longer, thinner and smoother, the less wave drag created. Coherently, fuselage of supersonic planes as Concorde are so similar to the Sears-Haack body. So indeed fineness is very relevant to know drag at supersonic speeds

Wing design: It’s all about providing lift. With better lift and trim management for example, you need far less surface area. The formidable F-35 load carrying parameter is a good hint at what kind of lift that tiny wing and lifting fuselage can generate. Such as is the 50+ AoA performance.

Wings optimized for subsonic and supersonic flight are very different, you just need to look a the sweep angle of F-35 compared to that of F-22. F-35´s wing is optimized for subsonic flight.

BTW, wing loading of the F-35A is very close to that of the F-16, so it is not a tiny wing.

The position of the engine is not as much dictated by the VTOL config than by other requirements. Stealth come in my mind as the strongest one: with the airframe surrounding the engine nozzle, you hide critical surface from radars, wash-out more air in the hot airstream or reduce your trim drag and surface deflections using far projected trim surfaces.

Have no way of proving this but extremely short nose and forward placed cockpit, together with current lift ratios between fan and nozzle of the B version (46/54 IIRC) indicate IMHO that the engine is already as backwards as possible for the given lift technology. Move the engine rearwards and you would need an even bigger lift and even more power drained from the turbine. Now compare that engine position with an F-16, Gripen or other modern fighter of distinguished aero efficiency or to the Yak-141 and tell me what the F-35 looks more like.

Had the F-35 been a CTOL fighter only, the engine could have been placed at the rear and space been created for weapons bays before the engine instead of being at the sides. This decision alone had the dramatic effect of compromising both the aero of the plane and its space for internal payload. I know this sounds theatrical but you don’t need to believe me, just do the exercise of playing around with some 3D design tool and try to make place for big internal bays in a compact airframe, then compare cross sections under the two approaches above and you will see what I am saying. As additional evidence, look at the 5G CTOL aircraft concepts around and look for any in which the weapons bays are at the sides of the engine as in the F-35, instead of being at the front.

To conclude rapidly, I would say that you can’t claim an argumentation because you are not able to see how it is done or build but should trust the fact that most KPP parameters were exceeded in term of performances (and multi-service requirements have historically not been the more complacent!)

That kind of trust the the services know what they do goes contrary to my understanding of critical thinking. Of course there are many issues you can just believe or not, but on many others like exposed above there are solid available evidence to form an opinion.

Have they been already tested on the Tu-160? I heard they were on test this year and the first units were to be delivered to Tupolev before end of the year

Well to discuss this piece by piece:
1. Engine performance, by which I believe you are referring to thrust to weight, acceleration, etc.
Reality is, that it is not a determining factor in the merge. The USAF did multiple studies on “dogfighting” both during and directly after the Cold War. One specific thing that was determined was that in the time that it takes for superior thrust to become a factor, the fight would be over. It was not a determinate of success. Not to say that acceleration isn’t critical in combat, it is, just not so much in the WVR arena. And the F-35 has excellent subsonic acceleration.

Fair enough. Some comments:

> Did such studies considered things as DIRCM and other countermeasures? Pk is going to be affected and therefore your need to endure a longer fight, both in terms of using more missiles, other kinds of them or even the cannon, manoeuvring and accelerating accordingly.
> Merge is maybe (in fact probably) complex and not only one on one.
> Good subsonic acceleration of F-35 is known, and is important. Remains to be seen, how it looks like against newer fighters and what F-135 updates can do in that regard.
> It is interesting to hear such argument used that way. Normally when pondering Russian designs, Western sources submit that, by trying to point the nose to the opponent at high AoAs they loose speed and become vulnerable. Following your logic, they would have won by then and hence the loss of speed would not be relevant, wouldn’t you agree?

2. Speaking on one factor that was determined to be important in WVR combat “dogfighting” was situational awareness. So “putting your hopes in avionics” is exactly what research showed. Aircraft die in the merge because they lose track of overall tactical situation, become easy prey. And again, kinematic performance is not a determinant factor between fighter aircraft in a merge.

Do not dispute that knowing what surrounds you is crucial, it obviously is. What I mean is, avionics and sensors are much easier and faster to update than airframe issues. Therefore should be of little comfort to have an advantage on the avionics but a handicap on the airframe side. One may go away, the other will remain.

Looking at what I had written in previous post above, vis a vis F-22/-35. The F-22 was designed to operate at higher altitudes and speeds than the F-35 (or most any other fighter). It will outperform the F-35 at higher altitudes, and enters the fight with more energy. In BFM exercises with “canned” setups, different simulated weapon performance, etc. It wouldn’t surprise me to learn the F-35 is at a slight disadvantage to the F-22, Typhoon, Rafale. On the other hand, in simulated combat scenarios like Red Flag, I also am not surprised how welll the F-35 performs.

In regards to the exercises mentioned above, the RoE determining the setups would be interesting to know.

Would also like to know more about those exercises of course, sadly we get very little info. Thing with the F-35 is, it will be the main air superiority asset of most of the involved air forces buying it. For them it is of little comfort to know that the USAF always thought in the F-22 as back-up of the F-35 for air dominance. That is not enough for them.

@TomcatViP:

respectfully, I think a certain level of criticism to the F-35 airframe is well justified and more importantly, necessary. If I am not wrong, the plane has improved compared to the F-16 mainly in that due to twin tails and FCS it has practically removed AoA limits. F-18 is already controllable up to 50º AoA and beyond. So this is a positive but hardly an advantage compared to many modern aircraft and essentially all potential 5G rivals.

In regards of weight, plane grew from the X-35 demonstrator to the point it is already in the limits (especially the C version) of being a heavy strike fighter. This makes very difficult for a single engine to provide a level of performance in line with i.e. the F-22. It has also complicated the logistics for USN due to engine size growth

Very big cross section (>8 m2) , wing design and very short and thick body are indeed an issue where supersonic performance is needed. Max speed of the plane is below cruising speed of F-22… and many feet below. Therefore, engagement windows will not look very symmetrical for both.

Rivals of the F-35 are not the F-16 and rest of 4G fighters, but other 5G designs. That it has some decent kinematic parameters is mainly due to an extraordinary engine that compensates for the airframe… when compared to 4G designs. If other countries finish their development of 5G engines, or if in the West 4G fighters receive modern, F-119 derived ones, the perspective can turn grim all of a sudden.

@Dr.Snufflebug:

Are you sure they have substituted the engines? They don’t look like NK-32s and it seems they cancelled this as well as some other upgrades.

@stealthflanker:
lead designer mentioned it to be in the ball-park of the F-22, between 0.2 and 0.5 m2. Band was not indicated as far as I know. Everybody implies X band but it may not be the case! Maybe somebody has more information or can correct what I write here.

As said, this is a complex and sensible matter and no side is going to disclose all the tricks in public. Hence the scarce progress in this perennial thread discussion…

Thanks for clarifying stealthflanker, I supposed this had to do mainly with contractual issues since Russian AF is not having such maintenance problems. In fact sortie generation rates in Syria have been remarkably high

@RALL:
to be clear, I generally do not believe statements from Russian and US officials or manufacturers are to be taken at face value. You don’t give your potential rivals classified information for free to help countering your weapons systems… unless you know they already know or can estimate those values accurately. Sometimes it can even be misinformation or bluffing, who knows. So, those very low values stated by US officials are not “100% clear” to me. But imagine they are so for X band… advanced IADs do not illuminate the target from only one angle and are multi-band. Radars which are not even emitting can pick up scattering from another radar illuminating the target from convenient aspect. While signature management provokes RCS spikes that are theoretically limited to some angles, diffraction is going to happen and is going to scatter small portions of the radiation to the radars listening, even outside of those exact angles. So it is nice and good to have a very low frontal RCS and the correct thing IMHO to do in signature management but tactical reality is not limited to that, if your enemy has a decent, modern radar AD coverage. Also low frequency radars (which are today much more precise than normally claimed in the media) or even OTH radars illuminating targets from above can allow higher frequency ones to be cued to the right sector of the sky with the advantages this means for detection range.

Regarding what the Russian scientists can know about the F-22, well the aircraft as any other object follows the laws of physics and as such there is the possibility of simulating its RCS. If the guys doing the simulation know all applicable phenomena and technological possibilities then they could in fact reach a realistic estimation. That is what justifies Western claims about lack of stealth on the Su-57 first of all. And Russians are, at least on the theoretical side of the story, well equipped as you know. They claim signature information from Syria (an issue about which USAF guys were not comfortable at all) confirmed their simulations. Again, we are left to guess if this makes sense or not but it should not be rejected without some analysis I think.

BTW, I very much doubt a long range radar detection of a US VLO plane would be disclosed as you claim. This would be a very major blow to American credibility and military prestige and hence intrinsically harmful to national security and businesses. Where would the F-35 program go in that case for instance?

As to the F-22 manoeuvring themselves into dead spots of Iranian aircraft, this is possible even with legacy fighters. Do not know or dispute the case you refer specifically but the notion that such feats prove any concrete level of stealth in a general way.

@moon_light
Agree, one single RCS value without scattering diagram is not saying much as discussed above. Also agree that no side should be believed blindly.

In regards of manoeuvring into the dead spots of you rival, maybe it is not stated publicly but it is completely logical, do you see it differently?