Defense Issues

Defense news and analysis

Saab Gripen vs F-35

Posted by picard578 on March 16, 2013

AIRFRAME PERFORMANCE

Contrary to some claims, F-35 has rather simple and conventional aerodynamics. Basic configuration is similar to F-16, however lack of LERX, and use of lower-performance but stealth-friendly chimes for high AoA lift enhancement, means that it will have far less body lift than F-16 to help compensate for its high wing loading, and wing lift will also be smaller at high AoA. Result will be (for a modern fighter) disastrous turn rate.

Further, it has internal carriage, which adds drag compared to low-drag AAMs and pylons, and its far higher weight also means more inertia that has to be overcome.

Gripen is, on the other hand, built for maneuverability. Close-coupled canards, wing-body blending, and wing shape all help increase lift during maneuvers, allowing aircraft to both achieve higher angles of attack, and to turn tighter at same angle of attack. Particularly canards create vortices that reattach air flow to the wing at high angles of attack. Aside from helping air flow over the wing, Gripen’s canards also help air flow over the body. Canard also has advantage over tail as the control surface – as center of gravity for modern aircraft is towards rear of the aircraft, usage of canard results in longer moment arm than it is case with tail. Further, Gripen has large degree of wing-body blending, and it’s wing loading is also far lower than that of F-35.

While thrust-to-weight ratio is below 1 for both aircraft, Gripen has far lower drag than F-35, partly compensating for F-35s superior thrust-to-weight ratio. While F-35 achieves maximum of Mach 1,6, clean or not, Gripen can achieve speeds of over Mach 2 clean.

 

SITUATIONAL AWARENESS

First thing that can be noticed about both Gripen and F-35 is that neither has rearward visibility from cockpit. In Gripen’s case, attempt was made to attenuate the problem by installing rear-view mirrors onto the canopy forward frame. However, while Gripen’s visual and IR signatures are far lower than F-35s, Gripen itself does not have IRST, which means that F-35 may be able to detect it first.

 

WEAPONS

In gun department, Gripen uses German BK-27, a 27-milimeter revolver cannon which was also supposed to be equipped to F-35, but in the end, F-35 received 25-milimeter rotary-barrel GAU-22. In air-to-air combat, BK-27 has a large advantage over GAU-12 in that delay between pilot pressing the button and full rate of fire being achieved is just 0,05 seconds, as opposed to 0,4 seconds for GAU-22. Further, on F-35, trap door must open if gun is internal (and assuming it wasn’t open already), possibly adding another 0,5 seconds to process. Maximum rate of fire is 1 700 rpm for BK-27, and 3 300 rpm for GAU-22. Muzzle velocity is 1 025 m/s for BK-27 and 1 040 m/s for GAU-22, but BK-27s shells – weighting 260 g as opposed to GAU-22s 184 g for HEI and 215 g for AP – will bleed off speed slower, and be less affected by wind and other air turbulences.

Therefore, in first half of second – which is crucial in dogfight; rarely will opponent fly in the same directon for full second or more – BK-27 will fire 14 projectiles massing 3,64 kilograms, and GAU-22 will fire 16 projectiles massing 2,94 – 3,44 kilograms, but only assuming that F-35 pilot opened gun doors beforehand – if he didn’t, GAU-22 will not fire any projectiles at all. GAU-22 may be a sign that US have (finally) understood that 20 mm cannons are not sufficient for modern air-to-air combat, similar to WW2, when they delayed introduction of 20 mm cannons instead of 50 caliber machine guns as main fighter armament well into Korean War. However, it is more likely that it was thought of as compromise between air-to-air and air-to-ground combat, considering that F-35 is primarly ground attack aircraft.

 

FORCE PRESENCE AND SUPPORTABILITY

While F-35A costs 197 million USD flyaway, Gripen C costs 40 million USD flyaway. As such, Gripen can provide almost 5 times as large force as F-35A can. Further, due to Gripen’s lower maintenance and turnaround times, same force will be able to fly far more sorties. Gripen is also designed to operate from roads, and has STOL capability, something that F-35A lacks, though not the (even more expensive) F-35B.

 

5-TH GENERATION?

According to this article, Lockheed Martin’s definition of 5-th generation fighter is following:

– stealth
— high maneuverability
— advanced avionics
— networked data fusion from sensors and avionics; and
— the ability to assume multiple roles.

Comparing F-35 and Gripen, it can be seen that while F-35 is stealthier on radar, Gripen has far lower IR and lower visual signature. Unlike F-35, it also has high maneuverability, and both aircraft have advanced avionics and multirole capability, while networked data fusion will be avaliable on Gripen NG. F-22 has high maneuverability but is not multirole, while Rafale and Typhoon only lack stealth. Thus, F-22, F-35, Typhoon, Rafale and Gripen NG are all equally 5-th generation aircraft, with Gripen C/D being just one step away.

 

And while another article defines fifth generation fighter as “being able to operate in anti-access environment featuring integrated air defenses…”, that capability can also be achieved in several ways, radar stealth being just one aspect of survivability, and rather limited one considering proliferation of passive sensors.

31 Responses to “Saab Gripen vs F-35”

  1. wow! Gripen NG must be the silver bullet we have all been waiting for. Too bad it is only a paper plane. If only half of this was correct it would have been in production by now, with lots of customers knocking on the door.

    • picard578 said

      This is about Gripen C, not Gripen NG. As for Gripen NG, it is still in development, and at least Swiss are not considering bailing out of project, unlike F-35 countries; and that despite the fact that F-35 project has entire political and diplomatic weight of United States behind it, unlike Gripen.

  2. Dan Bray said

    Something of interest to us war geeks; The canards primary advantage is that unlike a conventional rear tail plane, they will stall before the main lifting surface. This is an added safety bonus which, combined with the Gripen’s low inertia and low wing loading will lead to a much shorter take off run when compared to the f35’s. It may sound trivial, but the end result is that the Gripen can land in more places, on shorter and rougher runways because it can fly slower.

    • picard578 said

      That is for long-arm canards. Close-coupled canards actually add resistance to departure and allow for post-stall recovery capability; take a look at this (from Saab Gripen analysis):

      “When giving adverse aeliron input, flat spin starts at up to 90 degrees per second rotation, and can be stopped by pro aeliron input. Aircraft has demonstrated spin recovery capability for complete cg and AOR range, as well as control capability in superstall, allowing recovery.”

      • Dan Bray said

        They do provide more lift, and assist in spin recovery. They would still assist in a shorter, slower take off and landing by deflecting air flow across the top of the wing to delay stalling.
        My previous statement applied to long arm canards, please disregard.
        I don’t know how effective the chimes are on the F35, but they would be better than nothing.

        On another subject, one interesting difference between these aircraft is the projected cost of operation per hour. According to Jane’s; $4700 for the Gripen, $21000 for the F35. Granted, these figures are estimates. And this is not a political discussion, so we’ll ignore prior cost estimate performance for the F35! But is the F35 worth more than 4 Gripens?

        Perhaps the differences in these aircraft reflect different purposes? One as a lightweight defensive fighter to guard against invasion, the other as a deep strike fight primarily designed to penetrate enemy airspace and to act as a fighter as a last resort.

      • picard578 said

        Chimes on F-35 are certainly better than nothing, but are not as effective as either LEX or close-coupled canards. And no, F-35 is not worth the four Gripens, especially where air superiority is concerned.

        As for purposes, you are correct. But despite all talk about “unsurvivability” of 4th generation platforms, stealth does not seem to have improved survivability so far.

  3. Dan Bray said

    I recall watching a documentary on the F35. It showed a scene from U.S. congress where a statement was made. “Too big to fail.” The woman who made this statement then blatantly cast about for someone to blame for the continual failings of the F35. I’m an Aussie so this greatly concerns me. When politics take priority over actual defense effectiveness, we are put in the terrifying position of having our brown-nosing prime minister making decisions on subjects which they (former and current) have absolutely no idea about. End Rant.

    We need 2 aircraft. An air superiority fighter and a CAS attack aircraft. Basic requirements include;

    Long range, extended endurance as we don’t have effective tanker support

    Cheap to procure and use

    Effectiveness in their respective roles

    Survivability

    Both the Gripen and F35 are unsuitable. Their stealth and weapons/sensors are irrelevant when the lack of a second engine becomes a much more basic threat to survivability.
    For price, reliability and known effectiveness an existing design that is already established in significant numbers must be chosen. For a CAS craft nothing compares to the A-10.
    For a fighter, and with no political leanings whatsoever, it has to be the SU27. The F15 is a close second.

    As to comparing the F35 against the Gripen, that’s easy. The Gripen will at least have a chance at working in a combat environment. The F35 however shows all the hallmarks of a failed design.

    • picard578 said

      Yes, I watched the same documentary. Sad truth is, that in US at least defense procurement is a political process, actual combat effectiveness is ignored. F-35 is hyper-multirole design because it was thought it will save money. But it didn’t.

      As for why I have compared Gripen and F-15… F-35 is touted as F-16 replacement, but it is Gripen that has all important hallmarks of F-16 design: small, lightweight, maneuverable, cheap to buy and operate. Thus they are natural competitors.

      While I do understand your point about Su-27/F-15, fact is that heavyweight fighters are less effective air superiority platforms; but neither light- or medium- – weight fighters may be an option for some countries.

      • Dan Bray said

        I should clarify, the reason I would recommend those aircraft, particularly the Sukhoi is based in part on their fuel load. These aircraft are both old, I simply wish that the updated versions would be given consideration before being blindly labeled as 4th generation/unsurvivable.

        That’s for another discussion anyway.

      • picard578 said

        That’s why I said that neither light- or medium- -weight fighters are an option for some countries.

    • Henrik H. said

      According to this homepage http://gripen4canada.blogspot.no/p/this-post-will-be-effort-to-clear-up.html the single engine in Gripens is really not a problem. Its mostly a problem of the past. Only 2 out of 235 has been destroyed in accidents, with no fatalities so far. I dont know their source, but all i have ever read says single engine jets nowadays are quite reliable. Cheers

  4. Swede in Australia said

    If the Saab Gripen would have been a US produced aircraft, it would have dwarfed F16 and F18 in both volumes and geographical spread!

    You cannot compare aircraft with aircraft when not produced by the same country or ‘defence sphere’.

  5. Outside said

    I believe the Gripen NG to be the best suited aircraft for Canada…capability, initial outlay cost, maintenance cost, and interoperability. Sadly it is highly unlikely we will get it, especially now that SAAB has pulled out of the contest.

    It will be F-35 or Super Hornet. And if the F 35, we will be dumping huge dollars into the program for years.

    Such an impractical direction for a country such as Canada.

    • picard578 said

      Yup… Super Hornet is 7,33-g-limited overweight pig, but is still better than F-35 which is limited to 9 g for A, 7 g for B and 7,5 g for C, and can’t operate in cold environments (such as Canada and Norway).

      • Stanislav said

        Well it seems F-35 got reduced performnace specs… http://www.flightglobal.com/news/articles/reduced-f-35-performance-specifications-may-have-significant-operational-impact-381683/

      • picard578 said

        And you can expect more reductions to occur in the future.

      • Another Guest (from Australia) said

        @ picard578,

        There was a damning report of the Super Hornet in areas of critical operational requirements, while praising it for its improved aircraft carrier capabilities when compared to the original F/A-18A-D Hornet – something not high on our list of essential criteria.

        Three sentences on page eight of the report say it all: “The consequences of low specific excess power in comparison to the threat are poor climb rates, poor sustained turn capability, and a low maximum speed. Of greatest tactical significance is the lower maximum speed of the F/A-18E/F since this precludes the ability to avoid or disengage from aerial combat. In this regard, the F/A-18E/F is only marginally inferior to the F/A-18C/D, whose specific excess power is also considerably inferior to that of the primary threat, the MiG-29.”

        The F/A-18E/F has a similar performance deficiences to the F-35 which the aircraft has a short range and does not have the performance envelope of a true air superiority fighter compared to the F-15, F-16, Rafale, Typhoon and Gripen. The Super Hornet will be outclassed by the Su-27/30 Flanker family by most regional nations in all key performance parameters, aerodynamic, bigger weapons payload, radar / sensor performance by widely available fighters.

        The F/A-18E/F is also acknowledged in the report as being no match for even the older and newer MiG-29 family. Space precludes quoting the report’s comments on the multitude of other areas where the Super Hornet is inferior to the 1970s-designed and 1980s-built original F/A-18 aircraft. Admittedly the Block II Super Hornet has a new APG-79 AESA radar and some electronic components not in the version Coyle gave evidence on, but the fundamental airframe and performance remain unaltered: it is heavier, slower, larger and uglier (its radar signature did not measure up to expectations) than the legacy Hornet.

        Evidently the underwing aero-acoustic environment and resulting vibrations are so violent that some weapons are being damaged in transit to the target on a single flight – dumb bombs are fine in that environment but not long-range missiles containing sophisticated and relatively delicate components. To me there is nothing super about this Hornet; perhaps “Stingless Super Dog” is a better descriptor.

        Some of the pilots say the aircraft is capable of pulling more than 7.5Gs, which it’s false.

      • picard578 said

        It is capable of pulling more than 7,5 g but only at expense of airframe life.

  6. […] equipment. Not even, in light of cheaper, more reliable European alternatives from likes of Saab, and […]

  7. Another Guest (from Australia) said

    @ picard578,

    During the Australian International Air Show 2013 (at Avalon, Victoria) one of the Hawk pilots (from No.76SQN) said when they were in Exercise Pitch Black 2010 they went up against the F/A-18Fs in BFM (Basic Fighter Manoeuvres) and they claimed the Hawk has a better turn rate and robust airframe than the Super Hornet, whereas the Hawk’s G limit is +8.5 compared to the Super Hornet is +7.5.

    Then later when the Super Hornets took on the handling display, the pilots also said (which I find this very laughable), “they don’t want to break the aircraft” meaning don’t pull more Gs. If they ever go to war for real combat. I thought to myself if the Super Hornet has a radar locked by the enemy fighter in BVR or WVR engagement what are the pilots thinking of this point, saying they don’t want to break it? You can’t just rely on EWSP jammers and stand-off missiles.

    • picard578 said

      You don’t want to go above operational g level outside combat as it reduces airframe life. So, F-18E won’t break airframe by going above 7,5 g, but it will not meet service life requireemnts if it does so.

  8. Justin Bronk said

    “Further, it has internal carriage, which adds drag compared to low-drag AAMs and pylons”
    – I’m sorry but that is simply untrue. Internal carriage is by its very nature a lower-drag option than pylon mounted munitions and even low-drag (recessed) AAMS. What it does add to is airframe weight and complexity.

    • picard578 said

      That depends. Conformal wingtip carriage (F-16, Gripen, Rafale) or conformal body carriage (Typhoon) will add less drag than internal carriage. On standard hardpoints, there will be drag penalty, but not as large as typically assumed.

  9. Joe said

    Gripen needs improvements right out of the box. It boasts a small radar signature. (Not as small as f 35’s) it’s actually more stealth were it counts, the heat signature. However it still needs irst. Personally I would do anything to get better dog fighters WVR. Even if I had them flying radio silence following a f 22. There’s no point in the f 35 flying like a pick up truck.

  10. yoron said

    You’re missing a important part as it seems to me. To define whether you will be defending or attacking? Also whetehr you expect yourself to become a cog, defined and fitted, for a bigger (NATO) picture, or, defending your nation? Gripen was built to be modular from the beginning, supersonic, through good design also able to pass into this region without need of afterburner from the beginning., Sturdy as the best Russian counterparts it was expected to go up against, when first designed. Sweden built it to fit a Russian attack. With the possibility to use 400 m of any normal hiway, or equivalently not paved roads it was not necessary for it to be able to reach the other side of the world. What was needed was a modular very good airframe, good radar etc, low IR and visible signature, and fast response (minutes from warning) and repairs if wounded (means a real good modular design) on that same road, by a few ordinary mechanics in a matter, or at most, some hour of repairs. It’s still ‘before its time’ in that matter, very few aircrafts have the same rugged modularirty..

    Add to that the Swedish peer to peer datalink, enabling a gripen to go in totally dark (no electronic signature, and a very small IR), acquiring a target without use of radar, tracking and following up on its missile shot, all the way to its finish. Then you get a really rugged system for defense. What most Countries today seem to dream of though is the opposite, attack not only defense. So they want both, with SAAB now triying to accommodate that rather weird vision. What Country’s are Australia planning to attack? Or Canada then?

    Alaska?

  11. E said

    Picard578 is absolutely right in most senses. IRST is coming in the Gripen NG (Gripen E/F). Quite seldom I read about the Gripen in a chat and find it correct. This is one of few exceptions…The opinions about the F-35 is also for the most part something that I agree upon. It is a pity that SAAB has abandoned the competition in Canada. Probably because of “unlikeliness” that Canada should go for anything but US designs/solutions…apart from that, Gripen is probably a more or less perfect choice for them. Cheap, reliable, easy to maintain, top-notch performance…

    /E

    • I do like the Gripen, but I really do think 2 engines are a requirement. Based on current aircraft, I tend to lean towards the Rafale as the best single airframe solution for Canada.
      But could also see a compromise solution being a couple squadrons of Gripen NG and life extension for the best of our F-18’s, and reassess the situation in 10+ years.

      • picard578 said

        Gripen is designed for operation in conditions similar to Canada, though you might make a case for twin-engined aircraft based on Canada’s sheer size.

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