totoroas the superimposed image of su27 shows, it has more weight aft of the main landing gear. Tails are bigger, weigh more, theres less intakes hanging in front of the MLG, tailboom is aft, engines are at least a meter more aft, etc.
totoroOh come on, give the guy a break. MLG here should be the acronym for main landing gear. It is positioned too far to the back of the plane, meaning the center of mass is too far in front of it. As a result the aircraft would have a much harder time rotating during take off. Also, it puts too much weight on the front landing gear, which would require more structural beefing it up, meaning more mass to make it strong enough to withstand the extra pressure, and it’d make the plane somewhat less manouverable on the ground.
totoroWS10 seems to be much more comparable to that engine, number of fan stages, compressor stages and turbine stages, as well as in the number of stator and rotor blades on the engine face.
That being siad, number of stages doesnt really tell us much as when we look at various modern engines – f100-229, f135, ej200, etc we will find a vast range of differences, from 6 to 10 compressor stages, 3-4 fan stages, some use 4 turbine stages, some 3, etc…
totoroNo one claimed double the range for aim120d. The only official claim was “50% longer range over aim120C” Thing is, we dont know which model of aim120c is the reference there. That statement has been around for several years, before model C7 entered service. C7, in itself, has the same rocket motor as C5/C6, and somewhat increased range due to a better choice of flight profiles. It may very well be 50% more is refering to C5/C6. In any case, if i had to pull a number out of my rear, i’d put 120d in the 140-160 km range, a good bit of which is achieved due to a ballistic profile, meaning there would be no motor running for a good part of that distance, and a no escape zone would be significantly smaller, around 80 to 90km. Naturally, that is still huge compared to the no escape zone of previous amraams.
totoroThat’s the whole point of why the F-35 is far superior to the F-16/F-18, etc.. when carrying a similar load. It has far more agility with a combat load since its weapons are neither causing a drag nor inertial penalty, that the others have with weapons under the wings.
How can we say “far more” when we have no numbers to guesstimate from?
Lets have a f16 carry two amraams and two mk84 jdams. Amraams on wingtips, jdams on midwing pylons. How much drag is that? Depends on the speed. But lets keep in mind a F15 can do over 2.0 mach with 4 sparrows and two 2000 lbs bombs, as per USAFs SAC documents people keep refering to.
Such loaded f16 has still at least 35% less frontal area than a clean f35, as per comparison of drawings of front end of both planes. Now, while that does take into account added drag due to surface of pylons and weapons, we still have increased drag coefficient due to various airflow vortices being created around pylons. But how much does that increase the drag coefficient? We know it lowers F15s speed from mach 2.5 to around mach 2.15. Decrease would be even slower if top speed was, say, mach 1.5. We also have an image from the f16 manual citing the drag coefficient for the clean plane (with two aams, as thats the optimal condition for the plane) and comparing it with drag coefficient when it has also a centerline tank, a jammer and 12 mk82 bombs, carried on multiple ejector racks. Difference is more or less 100% more. Now this is the bit with most guesswork but i am willing to bet that a single pylon carrying a single mk84 is way more streamlined than a pylon carrying a larger ejector rack which is carrying 6 mk82 bombs. And there are additional pylons and cargo in the game. Would it be 100% more? or 10% How can we tell?
And, like we said, actual effect of added drag will be more important the faster planes are going. So the drag penalty can be debated but most of the time, drag is the lesser of two things influencing agility.
So we have inertial penalty, most of which comes from mass, is slightlyl on the side of f35, as it doesnt have the added mass of pylons, both ones carrying weapons and empty pylons that were carrying fueltanks.
Yes, f135 is a newer engine, and it has somewhat bigger bypass ratio. But if we look at the history of decreased fuel consumption for those two factors, we will see the difference is not that great, around 5, 10, 15%, depending on which turbofan engines we choose to compare.
No matter how we slice it, f35a is gonna weigh 15.5 tons, without any fuel.
F16c will weigh 11.5 tons, without fuel. F35’s engine may have better fuel consumption but it also need to deal with added drag. Overall, 20% bigger fuel consumption on the way to the battle seems probable to me. But thats only part of the story. While on the way to the battle the f16 will have somewhat bigger both area drag and slightly higher drag coefficient due to its fueltanks, (5-10% are and a not more added impact due to drag coefficient than we had from the mk84s), on the way back it will be clean, save for the pylons. F35 on the other hand, will have even bigger fuel consumption on the way back, as there is nothing to jettison and lower drag. Without all those weapons and tanks, the difference in drag increases and would be bigger than on the way in. We can only guess, of course, but I wouldnt take 30% bigger consumption out of the question.
So f35 may carry 8.5 tons of fuel, but it would also need 25% more fuel to do the same mission. To equal its mission, f16 would need some 6.5 tons of fuel. That is within limits of a f16 with internal fuel, a 300 gal centerline tank and two 480 gal tanks.
Now all this was to an extent guesswork but so would be any counterarguments as there is just not enough public data available. I am just pointing out possibilities. Ive said nothing about actual BVR perfomance which i do believe would be vastly on the side of f35. Though, one has to note, missiles do miss, and even with gross technological advantage, to date there wasnt a conflict where aams did more than some 80% kill percentage. In a conflict against a technologically equal opponent, missile kill percentage may drop quite lower to 20, 30 or 40%, as it was in the gulf war. Lets note US tech enjoyed a technological edge there as well. It is not inconcievable that 2 amraams per enemy plane would not be enough and that the fight would “degenerate” into a dogfight.
totoroTHose nice documents Peter G linked to suggest AOTD was there for close range target discrimination, which would be consistent with its nomenclature (DSU), as it was a fuze. I don’t understand how it would increase the range or enable tracking the target from the front in itself. The document suggests that was due to a seeker using novel materials and cooling.
http://www.alternatewars.com/SAC/AIM-9L_Sidewinder_SMC_-_November_1974.pdf
Another document This document would suggest the wavelegnths used by seekers in aim9L, aim9x and all the new IIR seekers are pretty much the same. If i’m reading it correctly it would suggest the imaging part doesn’t come from the a broader wavelength but from multiple, independent sensor elements making up one image. If anything, that approach could *broadly* be analoguous to AESA radars, as opposed to PESA ones. I dont see how such approach would increase total range, but i can definitely see how it could offer significant target discrimination qualities, once the target is close enough. Basically, in seeker terminology, I would imagine IIR is much more closely related to precision and counter countermeasures than to range.
That being said, as far as I could find, fighter borne IRSTs seem to use high mid bands, a little bit longer wavelengths than the missile seekers, while the various FLIRS for ground surveillance tend to use longer bands, 8-12 micrometers and so on. That has been the standard since the 80s, and even older IRSTs like ols27 used those. I’m sure today we have better processing that can extract better data from the sensors, offering somewhat better range. But it doesn’t seem plausible to be IRST ranges have, in the last 20 or so years, increased considerably. Oh well. 🙂
totoroIf anyone is interested, I took the most precise line drawings of f35a, f16c and rafale i could find, scaled them all and counted the pixels. For f35 i used a clean plane, for f16 i calculated in 4 amraams, 9 pylons and a alq 131 jammer pod. For rafale i added 7 pylons and 4 micas.
All taken into account, f35 had some 2% larger frontal area than the rafale and some 41% larger area than the f16c.
So clean f35 cant possibly be 300 bigger than a clean f16, not are clean rafale and clean f35 the same size, although the latter pair is much more closer in frontal cross section area than the former pair.
totoroIt doesn’t. IR has shorter range then IIR.
We seem to be having a massive misunderstanding here. Are you talking about Imaging infra red or something else under the acronym of IIR? And, just what do you define as IIR? In my book, infrared is everything from 1 micrometer to very long wavelengths, like hundreds of micrometers. If you define IIR as the long wave infrared, 8 to 15 micrometers, whereas IR is a separate band under that, then we have a clear misunderstanding. To me, difference in IR and IIR is not wavelength, but hardware and software accompanying the main sensor. IR systems have analog guidance where the seeker ‘sees’ just dots of various intensity, whereas IIR have an image of the target, potentially quite detailed, overlapping with the IR information from the sensor.
aim9L was certainly not IIR in my book. If anything, it was not working in the wavelength regions which could even be coupled with imagining. And frankly i havent seen anyone call it IIR to date. Yes it was all aspect, and because of the extra sensitivity which enabled it to be all aspect it got so famous over Lebanon and over the Falklands. To me, aim9L is still a regular, single color IR seeker. IIR seekers for missiles started only in the 90s, with various Iris-t, aim9x, python 5, asraam, mica ir and so on.
Aim9L did not have an onboard system that looked at the image and processed that data, determining what was a plane, and what was flares, or even deciding which part of the image is which part of the plane. To me, that constitutes an IIR seeker, not the wavelength it works in.
totorowhy would IIR have shorter range than IR? IIR should help with target identification, it should help with getting additional details about the target, it could even, in theory, help with range, if one can get clear enough image of the target and size it up to what the computer has in its database, concerning sizes of various enemy targets at various angles, etc…
BUT… how is IIR really different than IR with a tv channel, except that the former has computer in the loop that looks at the image? While the IR / IIR difference is huge for missile seekers, i dont see how Imaging infra red in itself increases range. Range should be a product of sensitivity of the sensor detecting infra red emissions. Perhaps in practice IR systems, as opposed to IIR, have somewhat lower ranges precisely due to various thresholds, as they have worse target identification qualities, so the pilot must not be overstressed to have to look at every offered IR emission through the TV channel – but IF one wanted to use their eyes and check every single emission with their own eyes (better system than any computer controlled image identifier) they should be able to achieve same ranges as IIR systems. IF they had enough time, that is.
Perhaps it is more an issue of theoretical range and average time to scan the sky and classify the targets. Kinda like mechanically steered radar array versus a phased array. Am I on the right track here?
totoroRussian manufacturers of irst systems for mig35 have no reason to downplay the capabilities of their product. yet they said this about their system:
http://www.aviapedia.com/video/new-mig-35-ols-video
And though i cant produce a link, i clearly remember some official statement about Pirate claiming double the figures of these, albeit for afterburning targets.
totoroBut shouldnt a higher temperature ALWAYS get detected before a lower temperature? Shouldnt a larger area ALWAYS get detected before a smaller area? Especially with IIR, which should look at an actual image, where physical size of an ploom should matter.
Having a treshold is fine, otherwise the system could get alarmed far too often, but I cant see how it is not a matter of degree…
totoroIn that press conference gen. charles davis said:
“It’s a 9g aircraft. Maneuvering at F-16 and F-18 combat weights there is no real difference in turn rates, turn radius and other air-to-air metrics,”
What does f16 and f18 combat weights mean? first off, those two are not the same. 3-4 tons more HAS to have an effect. Furthermore, combat weight of an f16, for a2a fight, is pretty much the same as empty weight of f35. To get the same range and same weaponry, f35 has to add weight, at least several tons, and then it gets to the point where it is, for the same range and weapon load, some 4 tons heavier than a f16. How is that comparable to the f16 combat weight? Also, is f18 c or e? weight differences are huge.
totoroum, but what constitutes long range detection? even the newest and best irsts (like ols35 and pirate) claim ranges of 90-15 km, first figure being target in full AB, seen from behind, latter figure being military thrust, target seen from the front. Even in full afterburner, from the front the range, as claimed by ols35 makers is some 45 km, at best. Though decent, even that can hardly be substitute for a radar…
totoroIt is highly likely the new chinese transport will have things in common with an70. Chinese have been talking to antonov bureau for years now. After the russians pulled out, it is not incredible to believe ukranians welcomed a new partner – the chinese. Only the chinese needed a larger plane… an70 has mtow of some 150 tons, while the avic newsbit mentions a 200 ton class plane, whatever that means. It may be the chinese bought all the blueprints and antonov expertise on the project, enlarged the designed and opted for turbofans.
Politics wouldnt allow western engines like cfm50 to be used on a military cargo plane, russians may be picky about exporting ps90, as they still hope to score with the il76 deal, so the only choice left was ws18, which is widely reported to be a chinese copy of d30kp. After all, it is a stopgap measure until a proper variant of ws10 is ready. After all, the prototype is yet to fly. Decent work can still be done for the next 2-3 years with weaker engines while developing the plane.
totorothere doesnt seem to be anything at the tip of that recce pod which would govern the need for the shape of the tip for anything save for aerodynamics. why give it a rather blunt tip if it was designed for supersonic flight? Wouldnt a sharp tip give it better performance?
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