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F35 Analysis expanded

Discussion in 'The Americas' started by Picard, Apr 23, 2012.

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  1. Picard

    Picard Lt. Colonel RESEARCHER

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    Program history

    F35 is designed to be LO interceptor / tactical bomber / ground attack / reconaissance / air controller and intelligence plane built in CTOL, STOVL, and CATOBAR variants.

    As Chuck Spinney puts it: "The problem was that each service had very different requirements. The Air Force wanted 1,763 cheap bombing trucks to replace F-16s and A-10s; the Navy wanted 480 "first day-of-the-war" deep-strike stealth bombers to compete with the Air Force in strategic bombing; and the Marines, still haunted by the ghosts of Admiral Frank Jack Fletcher and Guadalcanal, wanted to replace aging Harriers and conventional F/A-18s with 609 short takeoff vertical landing (STOVL) JSFs that will operate from big-deck amphibious assault ships if need be."
    In 2002, order was reduced by 400 planes, from 2853 to 2443 planes, and it is looking at further reduction. If F22 is any indication, US might end up with 713 planes, which will then cost 538 million USD per plane (F22s cost 411 million USD per plane), and produce 383,6 billion total program expense. However, as with F22, F35 is simply too big to fail.

    YF35 was even more limited than YF22 as technological demonstrator, and winner was determined by a flyoff demonstrating only low-speed handling, STOVL capability, and producibility with at least 70% parts commonality. Competetive prototyping, including working out bugs before large-scale production, was absent in both programmes. LRIP, meanwhile, escalates costs of any changes to design, essentially cementing it as well as allowing contractor to build up powerful political alliances by establishing nation-wide network of subcontractors. When weapon becomes obvious failure on performance and economical goals, it is already impossible to cancel, thus freeing contractor from obligation of having to fulfill its performance and cost promises.

    Developing engine has incurred cost overruns of as much as 850 million USD.

    There are also quite a few issues with the plane as well:
    - upper lift fan door actuator problems
    - ejection seat and pilot escape system failed tests
    - problems with restarting engine if it flames out in flight
    - braking on wet runaway is deficient
    four above issues were known in 2011; reported cost to fix them was 30 million USD per plane in lots 2-5

    Also, it is not one airplane for three services; with part commonality of 30%, it is basically three different airplanes, with only looks being similar.

    Costs

    Like F22, F35 is more famous for its perpetual increase in costs than for its hyped abilities. There are many resons for such increase, such as false cost estimates made by Lockheed Martin, reduced orders and problems with aircraft itself. Official numbers are 122 million USD as a flyaway cost, and 150 million USD as unit procurement cost. However, these numbers are outdated.

    Calculation, from data below, gives actual program cost, without accounting for planes themselves, of 235,87 billion USD.

    Unit costs

    In 2011, one F35 had a unit flyaway cost of 207,6 million USD and unit procurement cost of 304,15 million USD, as opposed to official numbers of 122 million and 140-150 million USD, respectively. Developmental costs have increased due to many patch-ups (such as structural strenghtening of rear fuselage) and fixes.

    Maintenance and operating costs

    F35s estimated cost per hour of flight is 35 200 USD in 2012 dollars. And that is for F35A, CTOL variant which, logically, should be easiest to maintain. Also, a leaked Pentagon report estimated that Canada's fleet of 65 aircraft will cost 24 billion USD to maintain over next 30 years.

    Strategical analysis

    Effects of numbers

    Effects of numbers are various. First, fewer planes means that these same planes have to do more tasks and fly more often, therefore accumulating flight ours faster and reaching designed structural life limit faster. Also, smaller force will attrite faster; more flight hours per plane will mean less time avaliable for proper maintenance as well as greater wear and tear put on planes, further reducing already limited numbers.

    In combat, side capable of putting and sustaining greater number of planes in the air will be able to put a larger sustained pressure on the enemy.

    F35s shortcomings – force size and quality

    F35, as it is obvious, is NOT a "low cost, affordable solution". With its flyaway cost of over 200 million USD, it is more expensive than F15, let alone F16 it is supposed to replace. Moreover, its low reliability and high maintenance requirements are going to reduce that number even more.

    Effects of training

    Wars in history – such as Yom Kippur War, Croatian War for Independence or Ottoman invasion of Europe – have proved dangers of overreliance on technology as replacement for doctrine, tactics and training. Whenever technology has been solely relied on, it had failed.

    F35 does not have a double-seat version, therefore harming training further; which is exceptionally noticeable with high training requirements for complicated operations like vertical landings. Simulators, meanwhile, cannot replace training – meaning that lack of training in two-seat STOVL variant will result in preventable accidents.

    Tactical analysis

    BVR combat

    Since development of first BVR weapons, each new generation of fighters would make someone declare that "dogfighting is a thing of past". Invariably, they have been wrong. In 1960, F4 Phantom was designed without gun – and then Vietnam happened.

    US went into Vietnam relying on a AIM-7 Sparrow radar-guided missile. Pre-war estimated Pk was 0,7 – Pk demonstrated in Vietnam was 0,08. Current AIM-120 has demnostrated Pk of 0,59 in combat do this date, with 17 missiles fired for 10 kills. However, that is misguiding.

    Since advent of BVR missile until 2008, 588 air-to-air kills were claimed by BVR-equipped forces. 24 of these kills were by BVR missile. Before "AMRAAM era", four out of 527 kills were by BVR missile. Since 1991, 20 out of 61 kills were done by BVR missile, while US itself has recorded ten AIM-120 kills. However, four were NOT from beyond visual range; US fighters fired 13 missiles to achieve 6 BVR kills; Iraqi MiGs were fleeing and non-manouvering, Serb J-21 had no radar, as was the case with Army UH-60 (no radar, did not expect attack), while Serb Mig-29's radars were inoperative; there was no ECM use by any victim, no victim had comparable BVR weapon, and fights involved numerical parity or US numerical superiority.

    In Vietnam, Pk was 28% for gun, 15% for Sidewinder, 11% for Falcon, 8% for Sparrow, and essentially zero for Phoenix. Cost of expendables per kill was few hundred dollars for gun, 15 000 USD for Sidewinder, 90 000 USD for Falcon, 500 000 USD for Sparrow, and several millions for Phoenix. Overall cost for destroying enemy with BVR missiles – including training, and required ground support – has never been computed.

    In Cold War era conflicts involving BVR missiles – Vietnam, Yom Kipuur, Bekaa Valley – 144 (27%) of kills were guns, 308 (58%) heat-seeking missiles, and 73 (14%) radar-guided missiles. Vast majority of radar-guided missile kills (69 out of 73, or 95%) were initiated and scored within visual range. In true BVR shots, only four out of 61 were successful, for a Pk of 6,6 %.

    In Desert Storm itself, F15s Pk for Sidewinders was 67% as compared to Pk for BVR Sparrow of 34%. However, Iraqi planes did not take evasive actions or use ECM, while there was persistent AWACS avaliability on Coalition part – none of which can be counted at in any serious war.
    Post-Desert Storm, there were 6 BVR shots fired by US during operation Southern Watch – all missed.
    Breakdown in BVR combat, offered by Air Power Australia, produces (when corrected for few unrealistical assumptions) Pk for BVR missile of 0,077.

    WVR combat

    In Desert Storm, US forces fired 48 WVR missiles, achieving 11 kills, for Pk of 0,23. However, historically, Pk for IR missiles was 0,15, and 0,308 for cannon. While F16s fired 36 Sidewinders and scored zero kills, at least 20 of launches were accidental, due to bad joystick ergonomy, which was later modified.

    F35s shortcomings in air combat

    F35 is overweight and underpowered – with a wing loading of 446 kg/m^2 and thrust-to-weight ratio of 1,07, it cannot hope to outmanouver any modern fighter plane – even ancient MiG-21s, with wing loading of 308 kg/m^2 can outmaneuver it. Actually, F35's wing loading is slightly worse than F105 Thunderchief.

    Indeed, many fire safeties had to be removed to save weight.

    Sukhoi fighters, which many countries which are member of the program want it to counter (UK will use far more capable Typhoons in AtA role, instead using F35 as self-defensable tactical bomber, which it is), are far more capable than F35 in air combat.

    Number of different capabilities and electronical systems in airplane necessitates second crew member – luxury that no F35 variant can provide. Task saturation can, and often does, result in "close calls" and mishaps. Place for second crew member was not put in – due to vertical landing requirement. Airborne Air Controller missions also require second crew member – in F/A-18 D/F, that work is done by Weapons and Sensors Operator (WSO) in back seat.

    F35s shortcomings in WVR combat

    F35 is, so much is obvious, designed as tactical bomber with limited capacity of self-defense. Its maximum G load is 7 – 7,5, dependng on version, versus 9 which is standard for modern fighter planes. Last time 7 Gs were an acceptable performance was Vietnam war.

    Its high wing and thrust loadings, as shown above, do not allow F35 to achieve manouverability required for a modern front line fighter. It is double inferior – in both wing and thrust loading
    – to most modern fighter planes. It also does not have a bubble cockpit; pilot's rearward visibility is literally zero, while its weapons, which require doors to open, do not offer it ability to perform dogfight-critical "snapshots" in order to shoot down enemy aircraft.

    It is also very noisy and relatively large aircraft, making it very detectable at visual range.

    F35s shortcomings in BVR combat

    First, it is not stealthy at all. Stealth is measured against five signatures – infrared, sound, visual, and radar footprint as well as electronic emissions. Visual, by definition, is not important for BVR combat; but sound and infrared signature are impossible to lower enough for plane to be VLO, especially when supersonic. While it is not a shortcoming by itself, legacy fighters not even making any effort to lower it, it becomes one when coupled by its low numbers and maximum of two BVR missiles carried in VLO configuration – essentially necessitating use of 6 to 8 F35s to kill a single target (growth to four BVR missiles is planned, halving numbers given). On better note, F35 is equipped with IRST; however, it is optimized for ground attack.

    While F35s only hope to survive air combat is to "launch and leave", its maximum speed of Mach 1,5 means that most fighter planes in the world can easily overtake it and shoot it down – with gun, if necessary.

    F35 shortcomings in ground attack missions

    F35 is completely incapable of providing close air support. First, many major safety measures in regards to fire safety have been dropped due to increasing cost. Second, its high wing loading and high drag make it unable to slow down, and its lack of manouverability, thin skin as well as fact that engine is literally surrounded by fuel – which is also used to cool down aircraft's skin – coupled with lack of fire safety measures, make it extremely vulnerable, and unable to go low enough and slow enough to provide effective close air support.

    Inability of fast jest to provide effective close support was graphically demonstrated when, in Afghanistan war, 2001, 30-man combined US/Afghan team was ambushed by 800 Talibans. Single B1B which was probably nearby tried to help, but couldn't fly low and slow enough to reliably identify targets. Two A10s were sent - as soon as they opened fire with cannons, Taliban attack ceased, and A10s covered team for next 6 hours. (Taliban also tried to negotiate a release of some captured ANA members if US team was to call off A10 support).

    Comparasion with other planes

    F16

    F16 is far better fighter and bomber than F35. F16 does not carry weapons internally, allowing it to fire off shots quickly. Its cockpit visibility is far superior to that of F35; it has lower wing loading (431 vs 526 kg/m^2 loaded) and higher thrust-to-weight ratio (1,08 vs 0,87).

    Cost issue is completely in favor of F16. Whereas F35 has unit procurement cost of over 200 million USD, F16s unit procurement cost is 60 million USD for latest model, easily giving it 10:3 advantage in numbers.

    In Gulf War I, F16s flew 13 340 sorties, and had 3 confirmed losses to enemy action, 7 losses total; thus, loss rate was one plane per 4460 sorties for confirmed combat losses, or one plane per 1900 sorties for total losses – both far better than F117.

    F18

    F18 is also better fighter and bomber than F35. Unlike F35, which can only carry two 900-kg bombs without becoming non-stealthy, F18 can carry a total of 6 200 kg of external ordnance and fuel. Also, it costs up to 57 million USD, enabling numerical advantage of 3,6 to 1, in essence being able to deliver 12 times more payload for same unit cost – and that without going into its superior sortie rate.
    Its wing loading of 441 kg/m^2 and thrust-to-weight ratio of 0,96 (both for loaded) are superior to these of F35. Also, its cockpit design allows for rear visibility, unlike F35.

    A10

    In over 8 000 daytime missions in Gulf War One, A10 suffered 3 losses to IR missiles – in other three cases, plane was hit but returned to base safely. Meanwhile, 83 % of A10s that were hit made a safe landing. In Gulf War and Kosovo campaigns, A10s flew 12 400 sorties while suffering 4 losses – a one loss per 3100 sorties, far less than F117, which had 1 loss per 1300 sorties.

    In Afghanistan in 2001, 4-man US special ops team leading 26 ANA troops was ambushed by 800 Taliban. B1B bomber, sent to do "close support", failed to achieve any effect. Team leader, sgt. Osmon, asked for A10s. Two A10s were sent – after A10s opened fire with their cannons, Taliban ceased attack and dispersed. A10s escorted team during entirety of next 6 hours, a trip that would have normally taken 2 hours.

    That only serves to prove what is obvious to everyone but most close-minded people: that F35 has no capacity whatsoever to perform Close Air Support missions – it is too vulnerable, so it cannot fly as low and as slow as CAS missions require it to fly; it does not have a required loiter time – inefficient aerodynamics, small wing and large weight necessitate both high speed and high fuel consumption for it to stay in the air; and it lacks armament required to perform such missions, such as specialized cannon like GAU-8 A-10 is equipped with.

    Rafale

    Rafale has wing loading of 307 kg/m^2, and thrust-to-weight ratio of 1,1, loaded. Moreover, its close-coupled canards provide additional boost to its manouverability, and it is equipped with advanced IRST and weapons systems. Its price – 90,5 million USD flyaway, 145,7 million USD unit program cost for most expensive variant – means that it is also far superior design from strategic standpoint, easily providing 2:1 numerical advantage for same price.

    F117

    In Gulf War I, 42 F117s generated, at 0,7 sorties per day, less than 1300 sorties out of 33 000 flown, and made 2 000 laser-guided bomb attacks. Out of 15 SAM batteries in Baghdad reported attacked by F117s on first night, 13 continued to operate – these 15 strikes were also only strikes launched by F117s during war.

    While F117s did have zero losses, as opposed to 2 F16s, and 4 A10s lost, night was a much safer combat environment than day, and the F-117 flew only at night. Two squadrons of A-10s flew at least as many night sorties as the F-117. Their losses were the same as the F-117’s: zero. F-111Fs also flew at night and also had no losses.

    The A-10s and the F-117s flew in both the first Gulf war and the next war in Kosovo in 1999. The day-flying A-10s suffered a total of four losses in both wars. The nightflying F-117s suffered two casualties, both to radar missiles in Kosovo. However, F117 suffered 1 loss per 1300 sorties, as opposed to 1 loss per 3100 sorties for A10 in Kosovo and First Gulf War.

    In Kosovo war, Serbs launched 845 radar-guided SAMs – 2 F117s and one F16 were hit, for effectiveness rate of 0,36 %.

    B2

    F35 will be far less capable bomber than B2. Unlike B2, which was designed for nighttime low-level penetration and similarly low-level bombing, F35, being designed for daytime operations, and having far higher wing loading (446 vs 329 kg/m^2) cannot fly as low and slow, making it unable to reliably hit small targets. F35 is also far smaller, and has shape remiscent of legacy fighters, making it more vulnerable to VHF radars. Compared to B2, which can carry 80 230-kg GPS-guided bombs, F35 will, in stealth configuration, carry two 910 kg (A and C models) or two 450 kg (B model) weapons, and unlike B2, it cannot carry long-range air-to-surface standoff weapons.

    While B2 is seven times as expensive as F35, it does not have to be built in so large numbers (necessitated by F35 being replacement for five different airframes) and is easily several times as effective as F35 in bombing role; its size and shape also make it, in theory, harder to detect by low frequency radars, albeit its RAM is useless against them. Downside of B2 is that it cannot defend itself if it is detected (by IRST, for example); and while F22s in service may be used to provide it, they will be detected by VHF radars.

    However, above theoretizing is made noot by reports that B2 "has radar that cannot distinguish a rain cloud from a mountainside, has not passed most of its basic tests and may not be nearly as stealthy as advertised". While B2 is able to "hug" the ground to evade radar, but legacy platforms can be equipped with same systems – and radar used for that can easily be detected. Also, like F22, it is vulnerable to rain – specifically, its stealth coating is.

    Moreover, B2 carries only 4 times more payload than F16 despite costing – at 2.2 billion FY 1995 USD per plane – or 3,17 billion in FY 2010 USD - 52 times more. It is also maintenance-demanding, requireing environment-controlled hangars which exist only at Whiteman AFB – if these are destroyed, maintenance of B2 will be rendered impossible.

    One more problem is that B2 has design lifespan of only 30 years – as such, it costs 8 300 USD per hour, regardless of wether it is flying or not.

    Su-27 variants

    All Su-27 variants are capable of defeating F35 in one-on-one combat, due to combination of IRST, RWR, and good manouverability. Moreover, they are cheaper than F35 (Su-35 has estimated cost of 45 to 55 million USD, enabling them to outnumber it as much as four to one).
     
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  2. Picard

    Picard Lt. Colonel RESEARCHER

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    Counter-stealth technologies

    Stealth versus classical radar

    Su-27s radar performance has doubled over past 8 years, and by 2020 Flanker family radars will be able to detect VLO targets at over 46 kilometers. Also, US stealth planes fly mission with same radar jamming escorts that accompany legacy platforms.

    During the Gulf War, the British Royal Navy infuriated the Pentagon by announcing that it had detected F-117 stealth fighters from 40 miles away with 1960s-era radar. The Iraqis used antiquated French groud radars during
    that conflict, and they, too, claimed to have detected F-117s. The General Accounting Office, Congress' watchdog agency, tried to verify the Iraqi claim, but the Pentagon refused to turn over relevant data to GAO investigators.

    Also, even modern VLO planes have to operate alongside jamming planes, such as EA-6B or EA-18, when performing ground attack, confirming that even legacy radars are far from useless against VLO planes.

    Main way to reduce plane's radar signature is shaping – stealth coating simply deals with last few percetages. Which means that F35 is going to blow its radar stealth as soon as it maneuvers; additionally, its stealth capability was far lower than that of F22 from get-go.

    VHF radar

    While VLO planes are optimized to defeat S- and X- -band radars, VHF radars offer a good counter-stealth characteristics.

    Simply put, RCS varies with the wavelenght beacouse wavelength is one of inputs that determines RCS area.

    VHF radars have wavelengths in 1-3 meter range, meaning that key shapings of 19-meter-long, 13,5-meter-wide F22 are in heart of either resonance or Rayleigh scattering region.

    Rayleigh scattering regios is region where wavelength is larger than shaping features of target or target itself. In that region, only thing that matters for RCS is actual physical size of target itself.
    Resonance occurs where shaping features are comparable in wavelength to radar, resulting in induced electrical charges over the skin of target, vastly increasing RCS.

    However, their low resolution and resultant large size means they are limited to ground-based systems.

    Russians and Chinese already have VHF radars, with resolution that may be good enough to send mid-flight update to SAMs. Also, it is physically impossible to design fighters that will be VLO in regards to both low power, high-frequency fighter radars, and high-power, low-frequency ground-based radars. Such radars can, according to some claims, detect fighter-sized VLO targets from distance of up to 330 kilometers (against bombers like B2, their performance will be worse, but such planes have their own shortcomings – namely, IR signature and sheer size). Manufacturers of Vostok E claim detection range against F117 as being 352 km in unjammed and 74 km in jammed environment.

    Also, RAM coatings used in many stealth planes are physically limited in their ability to absorb electromagnetic energy; one of ways RCS reduction is achieved is active cancellation – as signal reaches surface of RAM, part of it is deflected back; other part will be refracted into airframe, and then deflected from it in exact opposite phase of first half, and signals will cancel each other on way back. However, thickness of RAM coating must be exactly half of radar's frequency, meaning that it does not work against VHF radar for obvious reasons – no fighter plane in world can have skin over half a meter thick.

    There is one detail that apparently confirms this: in 1991, there was a deep penetrating raid directed at destruction of VHF radar near Bagdad; radar, which may have alerted Saddam at first wave of stealth bombers approaching capital. Before US stealth bombers started flying missions, radar was destroyed in a special mission by helicopters. Also, during fighting in Kosovo, Yugoslav anti-air gunners downed F117 with Russian anti-air missile whose technology dates back to 1964, simply by operating radar at unusually long wavelengths, allowing it to guide missile close enough to aircraft so as to allow missile's IR targeting system to take over. Another F117 was hit and damaged same way, never to fly again.

    These radars, being agile frequency-hopping designs, are very hard to jam; however, bandwidth avaliable is still limited.

    Also, while bombers like B2 may be able to accomodate complex absorbent structures, it is not so with fighters, which are simply too small.

    Another benefit is power – while capacity of all radars for detecting VLO objects increases with greater raw output, it is easier to increase output of VHF radars.

    It is also possible for VHF radar to track vortexes, wake and engine exhaust created by stealth planes.

    Another advantage of low-frequency radars is the fact that they present poor target for anti-radiation weapons, making them harder to destory. Moreover, new VHF radars are mobile – Nebo SVU can stow or deploy in 45 minutes, while new Vostok-E can do it in eight minutes.

    IRST

    All Su-27 variants, as well as most modern Western fighters, carry IRST as a part of their sensory suite. Russian OLS-35 is capable of tracking typical fighter target from head-on distance of 50 km, 90 km tail-on, with azimuth coverage of +-90 degrees, and +60/-15 degree elevation coverage.

    Fighter supercruising at Mach 1,7 generates shock cone with stagnation temperature of 87 degrees Celzius, which will increase detection range to 55 km head-on. Not only that, but AMRAAM launch has large, unique thermal signature, which should allow detection of F22 and missile launch warning up to 93+ kilometers, while AMRAAM moving at Mach 4 could be detected at up to 83 kilometers.
    Integrating Quantum Well Infrared Photodetector technology greatly increases performance – Eurofighter Typhoon already has one with unclassified detection range for subsonic head-on airborne targets of 90 kilometers (with real range being potentially far greater).

    Infrared imaging systems (like Typhoon's or Rafale's) provide TV-like image of area being scanned, which translates into inherent ability to reject most false targets. Also, while older IRST systems had to be guided by the radar, newer ones can do initial detection themselves. Given that stealth planes themselves rely on passive detection in evading targets, using passive means in detecting them is logical response for fighter aircraft. Missiles themselves can use infrared imaging technology, locking on targets of appropriate shape.

    While there are materials that can supress IR signature of a plane, most of these are highly reflective in regards to radar waves, thus making them unusable for stealth planes, and other ways of reducing IR signature are not very effective.

    Passive radar

    Passive radar does not send out signals, but only receive them. As such, it can use stealth plane's own radar to detect it, as well as its IFF, uplink and/or any radio traffic sent out by the plane.
    Also, it can (like Czech VERA-E) use radar, television, cellphone and other avaliable signals of opportunity reflected off stealth craft to detect them. Since such signals are usually coming from all directions (except from above), stealth plane cannot control its position to present smallest return. EM noise in such bands is extensive enough for plane to leave a "hole" in data.

    However, simply analyzing and storing such amount of data would require extreme processing power as well as memory size, and it is prone to false alarms. It is also very short-range system, due to amount of noise patterns being required to detect, map and store.

    Lidar

    Infrared doppler LIDAR (Light Detection And Ranging; doppler LIDAR senses doppler shift in frequency) may be able to detect high altitude wake vortices of stealth aircraft. While atmospheric aerosoils are not sufficient for technique to work, exhaust particles as well as contrail ice particles improve detectability to point that aircraft may be detected from range well beyond 100 km; exhaust particles themselves allow for detection of up to 80 km.

    Wake vortices are byproduct of generating lift, and are, as such, impossible to eliminate – aircraft wing uses more curved upper and less curved or straight lower surface to generate differences in speed between two airflows. As result, upper airflow is faster and as such generates lower pressure when compared to airflow below the wing, generating lift. That, however, has result of creating vortices behind the trailing edge of the wing.

    Background scanning

    In that mode, radar does not look for stealth plane itself; instead it looks for background behind stealth plane, in which case sensory return leaves a "hole" in data. However, that requires radar to be space-based; or, if stealth plane is forced to fly at very low altitude due to defence net, radar can be airborne too.

    Another possibility is using surface-based radio installations to scan the sky at high apertures and with high sensitivity, such as with radio telescopes.

    As it is known to radio-astronomers, radio signals reach surface uninterrupted even in daytime or bad weather; and since map of stars is well known, it can be assumed that any star not radiating is eclipsed by an object, such as stealth plane. And as with very snsitive radio-astronomical equipment, every part of sky is observed as being covered with stars. It is also doable by less sensitive detecting equipment, simply by serching for changes in intensity of stars.

    Over-the-horizon radar

    Over-the-horizon radars invariably operate in HF band, with frequencies around 10 Mhz and wavelengths of 30 meters, beacouse it is band in which atmospheric reflection is possible. Also, at that point, target will create some kind of resonance and shaping will be largely irrelevant, as will be RAM coating, as explained above.

    However, lowering frequency of radar means that size of radar aperture has to grow in proportion to radar wavelength to maintain narrow beam and adequate resolution; other problem is that these bands are already filled with communications traffic, meaning that such radars are usually found in early-warning role over the sea.

    Such systems are already in use by US, Australia (Jindalee), Russia and China.

    Bistatic / multistatic radar

    Since VLO characteristics are achieved primarly by shaping airframe to deflect radar waves in other direction than one they came from, and thus make it useless to classic
    systems. However, such signal can be picked by receiver in another position, and location of plane can be triangulated.

    While every radar pulse must be uniquely identifiable, that feature is already present in modern Doppler pulse radars. What is more difficult is turning data into accurate position estimate, since radar return may arrive to transmitter from variety of directions, due to anomalous atmospheric propagation, signal distortion due to interference etc.

    Acoustic detection

    Planes are noisy, engines in particular but also airflow over surface. In former case, bafflers are added, while in latter, noise is reduced by shaping plane so as to be more streamlined. However, internal weapons bays, when opened, create a great amount of noise.

    Ultra-wide band radar

    UWB radar works by transmitting several wavelengths at once, in short pulses. However, there are problems: 1) it is more effective to transmit power in one pulse, 2) UWB antenna must work over factor of ten or more in wavelength, 3) it would offer numerous false clutter targets. In short, if, for example, UH frequency and VH frequency were used, such radar would combine UHF's and VHF's advantages AND disadvantages.

    Also, it is very hard to make RAM that would be effective against multiple frequencies.

    Cell phone network

    Telephone calls between mobile phone masts can detect stealth planes with ease; mobile telephone calls bouncing between base stations produce a screen of radiation. When the aircraft fly through this screen they disrupt the phase pattern of the signals. The Roke Manor system uses receivers, shaped like television aerials, to detect distortions in the signals.

    A network of aerials large enough to cover a battlefield can be packed in a Land Rover.
    Using a laptop connected to the receiver network, soldiers on the ground can calculate the position of stealth aircraft with an accuracy of 10 metres with the aid of the GPS satellite navigation system.

    IR illumination

    IR illumination – famed "black light" of World War 2, used in Do 17Z-10 and Bf 110D-1/U1 night fighters – works on exact same principles as radar, with only difference being EM radiation's wavelenght, which is in IR range.

    Since it is active technique, it also betrays location of emitter, and thus cannot be relied on for regular use by combat aircraft – althought it can be fitted instead of radar - but can be used by air defense networks.

    Detecting LPI radar

    F35s, like F22s, radar uses frequency hopping to counter radar recievers. However, it can only use relatively low spread of frequencies, and can be detected by using spread-spectrum technology in RWRs.

    Another way to hide radar signal is to include spread-spectrum technology; it is intended to reduce signature of radar signal and blend it into background noise. However, such radar still emits a signal that is 1 million to 10 million times greater than real-world background noise. It is relatively simple to build spread-spectrum passive receiver that can detect such radar at distance four times greater than radar's own detection range.

    There are other ways of making radar LPI: 1) make a signal so weak that RWR cannot detect it, and increase processing power, 2) narrow the radar beam and 3) have radar with far higher processing gain than RWR. Option one is impractical, and is only viable for few years, until newer RWR's are avaliable, even assuming it is initially successfull. Option two does not affect target being "painted", and option 3, closely connected to option one, is only, again, viable for few years.

    Conclusion

    All of above means that F35 is:
    1) Terrible at everything it is supposed to do
    2) Extremely expensive to operate and maintain
    3) As such, it would be better for US to scrap F35 until separate, non VLO replacements for F16, F18 and Harrier can be developed

    Additions

    RCS size vs detection range

    Target – RCS size in m2 – relative detection range
    Aircraft carrier – 100 000 – 1778
    Cruiser – 10 000 – 1000
    Large airliner or automobile – 100 – 1000
    Medium airliner or bomber – 40 – 251
    Large fighter – 6 – 157
    Small fighter – 2 – 119
    Man – 1 – 100
    Conventional cruise missile – 0,5 – 84
    Large bird – 0,05 – 47
    Large insect – 0,001 – 18
    Small bird – 0,00001 – 6
    Small insect – 0,000001 – 3
    F117 to VHF radar – 0,5 – 84

    Effective range is calculated by formula (RCS1/RCS2) = (R1/R2)^4, where RCS = radar cross section, while R=range.

    RAM coatings

    RAM coatings can be dielectric or magnetic. Dielectric works by addition of carbon products which change electric properties, and is bulky and fragile, while magnetic one uses iron ferrites which dissipate and absorb radar waves, and are good against UHF radars.

    Outside links
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    3 people like this.
  3. Manmohan Yadav

    Manmohan Yadav Brigadier STAR MEMBER

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    Nice Article

    Can you tell me more about IR illumination
     
  4. Picard

    Picard Lt. Colonel RESEARCHER

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    IR illumination - or "black light" - is active IRST; principles of operation are same as those of radar, but it uses infrared waves in UVA range instead of radio waves. Given that one of ways stealth coatings work is active cancellation, coatings of that type will be ineffective against it. However, it is very short (cca 400 nm) so there will be no other benefit from using it.
     
    Last edited: Apr 23, 2012
  5. tunguska

    tunguska Major SENIOR MEMBER

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    Picard Brother , what is your background means do u have military backgroud?
     
  6. Picard

    Picard Lt. Colonel RESEARCHER

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    I don't see how relevant that is.

    Note: always look at argument itself, not person's credentials. Even God can make a mistake.
     
  7. tunguska

    tunguska Major SENIOR MEMBER

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    I think you feel hurted. My intention was not that. But my question was really positive as your analysis is good. And want to see u in professional categories so that as a back up i have asked you. If you do not want to reveal then it is ok.
     
  8. Picard

    Picard Lt. Colonel RESEARCHER

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    My problem is that I have seen quite a few people - both on Internet and in media back home - waving their positions, diplommas etc. (even when given to them on basis of political suitability) as if it, somehow, proves their statements. So I have stopped looking at who was making argument, but rather what an argument contained.
     
    Last edited: Apr 25, 2012
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