Amiga500I understand as of the mid 1990s and introduction of AMRAAM, the mig-25/31 was certainly completely outdated but in the late 70s and 80s is a different scenario.
Say what now?
Performance of the initial versions of AMRAAM certainly left much to be desired. T’was very far from a wonder weapon when first fielded.
Indeed, I still wonder at the real-world performance of many of the much-vaunted radar guided missile systems even today.
Of course, what is good for the goose is good for the gander; which means that if all BVR missiles are equally ineffective, then the Foxbat/Foxhound are more affected than most as they are not built for closer WVR combat.
Amiga500Here someone can read in the section speed about heat stress and even present fighters will not be pushed behind Mach 2 briefly for that reason.
Depends on the materials you use around specific areas of the airframe Sens [and also the thermal heating vs. material volume – for instance a needle nose may reduce max temperature from skin friction, but it is bad as there is a small material section for the heat to go through – whereas a rounded nose will have more skin friction and greater overall heat soak, but there is more material to transfer the energy through, so material thermal loading is reduced – look into the space shuttle nose design if you can].
Trade off weight vs. thermal expansion vs. thermal fatigue resistance vs. cost vs. manufacturability vs. EM permeability.
Obviously pushing beyond Mach 2 for sustained periods is possible, the MiG-31 and SR-71 made operational careers out of it. But it depends what your willing to sacrifice to get there… and whether that trade-off is really worth it.
Amiga500Please excuse my thickness, how does the 777X differ from the 777?
787 wings and engines?
Using new wings and engines based off 787 design principles.
http://www.flightglobal.com/news/articles/dubai-boeing-plans-first-777x-flight-in-2019-393206/
Fuel burn will be 10% lower than on the GE90-115B-powered 777-300ER, while the GE9X should have a 5% lead in specific fuel consumption over the Rolls-Royce Trent XWB engine on the rival Airbus A350, says GE.
http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_11_17_2013_p0-637685.xml
“The -9X will have a 16% to 17% delta in fuel burn (compared to the current 777-300ER), and is an aircraft that is redesigned inside and has a new wing,” says Emirates Airlines president Tim Clark.
Obviously, reading the above; the numbers are not consistent, but they could imply a (fuel burn equated) drag reduction of 6-7% on the 777-X. I also seen wild claims vs. the A350-1000, but these seem to have been withdrawn. Someone must have got a bit ahead of themselves before others seen sense and had stupidly optimistic performance claims retracted.
Of other interest is that Boeing are intending to use a folding wingtip on the 777X to improve aspect ratio and with it L/D. It will no doubt be a significant factor in the aerodynamic performance of the wing; so is pretty crucial they can actually pull it off.
edit: Seems it wasn’t pulled from everywhere:
“The airplane will be 12 percent more fuel efficient than any competing airplane, necessary in today’s competitive environment.”
The above of course implies that the A350 wing is no more efficient than the existing 777 wing. Given the A350 is benefiting from the reduced t/c allowed by the composite spar (relative to the existing 777 metallic wing) and 20 years of advances in computational hardware and CFD techniques, that is highly speculative*.
*feel free to swap in ludicrous at the reader’s discretion.
Amiga500True.
Who only knows why, but it seems to be the case.
As soon as you starting messing with electronics or avionics that affect flight safety, your Design Assurance Level shoots up.
On the average engine; at DAL A, your gonna write the grand sum of about 10 lines of code a day.
[the rest of your day will be spent checking that each line doesn’t induce failure of some sort.]
Increase the software to encompass more systems; and the slower you go.
Hence why the JSF is a nightmare and why the Swedes have the right idea – completely separate flight software from mission software.
Amiga500If the Vertical Stabz has elements of composites, they would not last very long in M 2.5 enviroment and most Certainly not in a sustained M 2.5.
Again, it’ll depend on what types and what resins.
A polyimide resin is commonly known to be good to over 300 degC, thats about Mach 2.85 or so. You can bet they’ll have resins available that will do marginally better.
Amiga500Won’t that impede the proper functioning of the Leading edge apertures?
Assuming you meant (1) the leading edge devices and (2) the emitting electronics behind the leading edge surfaces rather than apertures (holes)…
1. Definitely not. The operation of slats (etc) are insensitive to the material they are made from unless it imposes severe compromises on rigidity and surface texture (not the case here).
2. The Foxhound has a renowned radar…. therefore the Russians already have materials capable of withstanding the heat while being permeable to radar waves.
Amiga500That would be wings, verticals and Horisontals Stabz made out of some sort of Allu-Titanium alloy.
Only the leading edges would really need it.
IMO less usage of Composites.
Depends what types and what resins…
Amiga500T-50 will be kinematic monster for sure, but I doubt that it’s maximum operational speed will be exceptional. Above Mach 2 friction heating becomes a significant issue demanding tailored solutions in the form of materials employed and so forth. T-50 cannot become a Mach 2.5+ machine ‘by accident’, and we have heard nothing regarding specific design work to enable this class of performance.
Yep… and?
They made the Foxbat and Foxhound capable of flying at M2.5+ sustained. They haven’t forgotten how they did that!
Even if it comes to it; the PVO version of PAK-FA can sacrifice some weight by using different materials along a number of leading edges and a different canopy material if needs be.
Y’know – sensible variants from a common baseline unlike some other programs.
Amiga500yeah but the Russians have stated they want a successor to the mig-31 too. so that would make it a hi-hi mix if they make it.
That’ll amost certainly be the PAK-FA.
I’m still strongly of the opinion it’s cruising and maximum speeds will be significant advances on anything fielded elsewhere today.
Amiga500What will replace the MiG 29/35 ? LMFS? Or Optionally manned crafts?
I think the question is; would they be replaced at all? [at least, by a dedicated aircraft.]
There is absolutely no doubt the Russians will look at the fiasco that has become the USAF’s hi/lo mix and think “hmmm, maybe we’ll just use the one aircraft to cover all roles”.
Points to consider:
– They don’t need STOVL.
– Their previous generation mix were twin-engined (Su-27/MiG-29), so acquisition and operating savings going from hi to lo aren’t as marked as say, F-15 to F-16.
– They have a PAK-DA program to undertake, so don’t need the resource contention.
– Putin will do whatever he wants to do; the military-industrial complex would not have the same lobbying effect on him as they do on the US state governors/congress/senate/white house.
– Russian doctrine continues to place very strong emphasis on kinematic performance; so what would any complement to the PAK-FA be? a mini-FA with smaller everything, including bays? Would it then have the necessary combat persistence to be effective?
Amiga500Sorry, just checked, my story above isn’t 100% accurate, although the general premise is.
2nd time around, the Eagles just got told of the general area the Blackbird would be in; not the exact flight path.
Amiga500If they hdn’t planned to fill some turning abilities with it, it would hve been a wave rider. EoA
Which would still have been a dead-duck before ever entering service.
There is a well known incident… or two incidents, of F-15s trying to intercept SR-71s back in the day. In the first instance, the Eagles had full knowledge of the Blackbird’s flight path, and the Blackbird made no effort to avoid….
Needless to say, this led to the F-15s “intercepting” the SR-71. Fighter pilots being fighter pilots, word soon got around the Eagles intercepted the Blackbirds and would have kicked their asses etc etc etc.
Which did not go down well in the land of the Blackbirds.
Well, there was a next time, again, Eagles had fore-knowledge of what the Blackbird’s flight path was supposed to be and were looking forward to kicking some blackbird ass – only this time the SR-71 crew decided not to play ball. A few degrees change of heading when approaching the intercept area and the Eagles ended up intercepting nothing but some humility.
Amiga500Sensors have come on quite a way since the SR71 evolved, so I would imagine flying in a straight line too fast and high for interception still works.
No matter how high, or how fast; flying in a straight line is never a long-term solution to avoid interception.
If you cannot change your flight path then you are a sitting duck. End of.
You don’t need much turning ability, but you need some.
Amiga500I’d have to say the most impressive demo of aircraft power I have ever seen was the SR-71. That thing took off so fast, I could barely turn my head fast enough to keep up with it.
Really?
That is surprising given the thrust:weight of an SR-71 is quite low.
It had to take off so fast as it has limited high lift devices.
Amiga500But you don’t agree, so let us leave it at that.
Fair ’nuff.
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