Jump to content
Sturgeon's House

Bash the F-35 thred.


Recommended Posts

One of the technologies that was first flown on the JSF that I fully expect everyone to copy is the new flight control actuator design:



In the previous generation of aircraft, power for the control surfaces is provided by a hydraulic pump that takes power from the aircraft's engine (or APU) and supplies power to hydraulic actuators at the control surfaces via a series of high-pressure hydraulic lines.





These lines snake all over the aircraft, and there is usually some built-in redundancy in combat aircraft.  No need to repeat the unfortunate experience of the early F-105, which had a single, non-redundant hydraulic line on the bottom of the fuselage.  In combat this was hit with some frequency, which locked up the controls and contributed to the absolutely appalling loss rate of the type in the Vietnam War:



All of these hydraulic lines add up to a lot of messy maintenance:



And they also add up to a significant amount of weight.


The F-35 is different.


In the F-35 there are no hydraulic lines running through the aircraft.  Instead, power is transmitted electrically to high-torque stepper motors that drive hydrostatic motors that drive the flight controls.  The hydraulic component is much smaller and is self-contained.  Instead of blowing out the system to do maintenance, the actuators can simply be unbolted and replaced.  The system is also lighter, as it deletes all of the hydraulic lines running all over the place.

Link to comment
Share on other sites

Good point.  It's hard to separate hydraulic lines very much because they're big and fat and wings need to be streamlined and skinny, and hydraulic lines need to be accessible.  Electrical wires are skinny and almost maintenance-free.  The EHA on the F-35 is clearly better than legacy systems, and another example of how even if the JSF program falls apart or some of the members go their own way, what replaces it will substantially be repackaged F-35 technology.

Link to comment
Share on other sites

Election promises.



Prime Minister Justin Trudeau’s party announced during last year’s election campaign that it “no longer makes sense” to buy a fighter with the F-35’s stealth, first-strike capability, citing skyrocketing costs for a plane that has been plagued with development problems. The Liberals vowed instead to buy a “lower-priced” aircraft and funnel the money saved into the Royal Canadian Navy.


This week, however, Department of National Defence spokeswoman Ashley Lemire said Canada plans to pay the latest required annual instalment to the Joint Strike Fighter program. She said the upcoming payment is estimated to be $32.9-million (U.S.)


The contribution would maintain Canada’s membership in the F-35 buyers’ pool. This gives Ottawa the right to buy F-35s at a discount and allows Canadian companies to continue to bid on supply contracts for the plane.


Asked why Canada remains in the Joint Strike Fighter program when the Liberals have eliminated the plane as an option, Defence Minister Harjit Singh Sajjan said the government is still reviewing how it should proceed on replacing the country’s aging CF-18 fighters.


“We can’t just make a very quick decision on something like this. We want to make a responsible decision as we move forward. We have to go through the proper requirements. Once we go through a proper process, decisions will be made at that,” he said.


One procurement expert working for the federal government, who spoke on condition of anonymity, said it’s unclear whether Ottawa could successfully defend against legal action should it bar jet maker Lockheed Martin and its F-35 plane from a competition. “They will have to decide whether they want to run a competition or face a lawsuit.… The easiest option for a variety of reasons is to run a competition and run it fairly.”


Link to comment
Share on other sites

This is an article from fifteen years ago when the actuator technology was new.


Some interesting quotes:



He adds that it can reduce aircraft weight by as much as 700 pounds (315 kg), but not because the system itself is lighter. "We’re taking weight out of the hydraulic system, weight out of the secondary power system, and out of the thermal management system, because we’re not generating as much heat. "But we’re offsetting it with a relatively more complex actuation system," Eicke adds. "If you don’t do the trade studies at the air vehicle level, you don’t see the benefits.





"With the previous hydraulic power system, you were dumping power into the actuator whether you were using it or not," he continues. "All that energy becomes heat–thousands of BTUs–and gets dumped into the fuel system.

"With the new (electro-hydrostatic) actuation systems, if you are not generating any heat, you don’t have to dissipate it. It’s a much cleaner secondary power system. We don’t have to provide a secondary and an emergency source of hydraulic power," says Eicke.

It frees us–gives us more thermal margin, which we can apply to other systems on the aircraft, or we can reduce our thermal management system weight and volume to compensate for that, making our aircraft smaller, lighter and cheaper."


So the system itself isn't any lighter, but it seems to reduce weight secondarily.  And apparently this weight savings can offset having more powered control surfaces on the aircraft.


Does the PAK-FA have EHAs, I wonder?  The Russians love putting control surfaces on absolutely everything:


It might help reduce the maintenance problems of this approach if they did use EHAs.





The J/IST program was intended to reduce the risk of certain new technologies chosen as candidates for the JSF program. The Air Force’s Advanced Fighter Technology Integration (AFTI) F-16 demonstrator aircraft made its first flight with the power-by-wire subsystems package last Oct. 24. Since then, flight control effectiveness has been demonstrated during mach 1.3 supersonic flight. The aircraft performed flying quality maneuvers while supersonic, including 5-g turns, pitch, roll and yaw "doublets" and sideslips. The tests also included low-altitude strike missions and the chance for the Lockheed Martin team to study the actuator and generator subsystems’ thermal behavior. 



Interesting how the F-16 AFTI rounded out its career.



This is a more recent article on the things that have been done to make the F-35 more maintenance friendly.



Paramore: On a F-16, for example, all your actuators are still hard-lined into the hydraulic system.  The actuators on the F-35 are fully self-contained:  four cannon plugs, some bolts, and it pops right out after you take your panels off.

On the F-16, you’d be four cannon plugs, eight bolts, two hydraulic lines, refuel or resetting the hydraulic systems, re-servicing those, bleeding and leaking them, and then doing the ops checks, not to mention if you had some kind of rigging you had to do for the actual actuator if it wasn’t just a straight swap, you’d had to go in and do all your rigging for that actuator.  The F-35 system self-adjusts the flight controls, so once you go in and replace an actuator, you run auto-rig, and the system auto-rigs the actuator.

Cool, so not only are the actuators easier to replace, getting them harmonized with the flight controls is easier too.



The endgame for the F-35 is for the aircraft to report back to the ground before it ever comes back. Let us go back to our actuator as an example.  If you have a hydraulic actuator that’s starting to need replacement, let’s say the fluid level starts to deplete for any reason whatsoever, the system will detect that trend, report it back to the ground, and through that reporting, you start looking at the electronic data, you can determine when that EHA will have to be replaced. You can also have the CMMS system, and the PBL (Performance Based Logistics) system; identify a need to get one shipped to the site for replacement on that airplane.



Very slick, very streamlined.  The aircraft's parts report any problems to a computer on the aircraft, and then that information gets forwarded to the base and thence to the supply chain.  I'm liking what I hear.



So we have an HRC, which is a Health Reporting Code for a system.  And, for example, if an actuator sends out its HRC code and says, “I have this problem,” then when we pull that into the CMMS system, when the AFRS solution sets are built, that’s kind of like your old troubleshooting tree you were talking about.  It’s all electronic.


The system will say you have a HRC.  And the system will suggest you start with this AFRS solution set No. 1.  And you go through the tree to troubleshoot it.  It will then ask you, “did this fix your problem?” And if you click on “no,” then it says, okay; let’s try this solution set.  And you go down through it, and if it says, did this fix your problem; you go “yes.”


Now you’ve done two things.  You’ve not only gone through a troubleshooting tree electronically that you otherwise had to do with paper in the past, you’ve also started to solidify the data in the system because you told the system via feedback.  Yes, this fixed my problem.



And there's a machine-learning system that helps ground personnel troubleshoot common issues.  Also slick and potentially quite good.



Paramore: It is analogous to the shift of going from Windows to Macs.  And if you fail to open your mind, you’ll fail the transition.  Because, you know, everybody is used to their little PC running Windows, doing it the way they’ve always done it, the way they always want to do it.


It is more like Apple than Windows.  Windows shifts through a series of new systems, XP to Vista to Windows 7. Now we’re in an Apple-like world, where you can run 64-bit apps in a true 64 environment and screaming past everybody else.


SHIT.  The program is doomed.

Link to comment
Share on other sites

Holy fuck that last bit is a towering edifice of stupid. Remind me to go on a rant about stupid bullshit UI elements that have gone unchanged since the first version of OSX and iOS. Basic things like the dock and the stupid grid of static icons.


The only hope is that it's such a giant goddamn tower of dumb that it gets the tower of babel treatment.

Link to comment
Share on other sites

A back-of-the-envelope calculation of the F-35's WVR maneuverability.  This is in line with similar analyses; the F-35's performance isn't stellar when compared to previous generation fighters with no weapons.  When the planes actually have weapons the F-35 pulls ahead thanks to the drag-free* internal weapons carriage.


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Similar Content

    • By Tied
      Why does everyone have such a raging hate boner for it?
    • By LostCosmonaut
      Compared to the most well known Japanese fighter of World War 2, the A6M “Zero”, the J2M Raiden (“Jack”) was both less famous and less numerous. More than 10,000 A6Ms were built, but barely more than 600 J2Ms were built. Still, the J2M is a noteworthy aircraft. Despite being operated by the Imperial Japanese Navy (IJN), it was a strictly land-based aircraft. The Zero was designed with a lightweight structure, to give extreme range and maneuverability. While it had a comparatively large fuel tank, it was lightly armed, and had virtually no armor. While the J2M was also very lightly built, it was designed that way to meet a completely different set of requirements; those of a short-range interceptor. The J2M's design led to it being one of the fastest climbing piston-engine aircraft in World War 2, even though its four 20mm cannons made it much more heavily armed than most Japanese planes.

      Development of the J2M began in October 1938, under the direction of Jiro Hirokoshi, in response to the issuance of the 14-shi interceptor requirement (1). Hirokoshi had also designed the A6M, which first flew in April 1939. However, development was slow, and the J2M would not make its first flight until 20 March 1942, nearly 3 ½ years later (2). Initially, this was due to Mitsubishi's focus on the A6M, which was further along in development, and of vital importance to the IJN's carrier force. Additionally, the J2M was designed to use a more powerful engine than other Japanese fighters. The first aircraft, designated J2M1, was powered by an MK4C Kasei 13 radial engine, producing 1430 horsepower from 14 cylinders (3) (compare to 940 horsepower for the A6M2) and driving a three bladed propeller. The use of such a powerful engine was driven by the need for a high climb rate, in order to fulfill the requirements set forth in the 14-shi specification.
      The climb rate of an aircraft is driven by specific excess power; by climbing an aircraft is gaining potential energy, which requires power to generate. Specific Excess Power is given by the following equation;
      It is clear from this equation that weight and drag must be minimized, while thrust and airspeed are maximized. The J2M was designed using the most powerful engine then available, to maximize thrust. Moreover, the engine was fitted with a long cowling, with the propeller on an extension shaft, also to minimize drag. In a more radical departure from traditional Japanese fighter design (as exemplified by aircraft such as the A6M and Ki-43), the J2M had comparatively short, stubby wings, only 10.8 m wide on the J2M3 variant, with a relatively high wing loading of 1.59 kN/m2 (33.29 lb/ft2) (2). (It should be noted that this wing loading is still lower than contemporary American aircraft such as the F6F Hellcat. The small wings reduced drag, and also reduced weight. More weight was saved by limiting the J2M's internal fuel, the J2M3 had only 550 liters of internal fuel (2).
      Hirokoshi did add some weight back into the J2M's design. 8 millimeters of steel armor plate protected the pilot, a luxurious amount of protection compared to the Zero. And while the J2M1 was armed with the same armament as the A6M (two 7.7mm machine guns and two Type 99 Model 2 20mm cannons), later variants would be more heavily armed, with the 7.7mm machine guns deleted in favor of an additional pair of 20mm cannons. Doubtlessly, this was driven by Japanese wartime experience; 7.7mm rounds were insufficient to deal with strongly built Grumman fighters, let alone a target like the B-17.
      The first flight of the J2M Raiden was on March 20th, 1942. Immediately, several issues were identified. One design flaw pointed out quickly was that the cockpit design on the J2M1, coupled with the long cowling, severely restricted visibility. (This issue had been identified by an IJN pilot viewing a mockup of the J2M back in December 1940 (1).) The landing speed was also criticized for being too high; while the poor visibility over the nose exacerbated this issue, pilots transitioning from the Zero would be expected to criticize the handling of a stubby interceptor.

      Wrecked J2M in the Philippines in 1945. The cooling fan is highly visible.
      However, the biggest flaw the J2M1 had was poor reliability. The MK4C engine was not delivering the expected performance, and the propeller pitch control was unreliable, failing multiple times. (1) As a result, the J2M1 failed to meet the performance set forth in the 14-shi specification, achieving a top speed of only 577 kph, well short of the 600 kph required. Naturally, the climb rate suffered as well. Only a few J2M1s were built.
      The next version, the J2M2, had several improvements. The engine was updated to the MK4R-A (3); this engine featured a methanol injection system, enabling it to produce up to 1,800 horsepower for short periods. The propeller was switched for a four blade unit. The extension shaft in the J2M1 had proved unreliable, in the J2M2 the cowling was shortened slightly, and a cooling fan was fitted at the the front. These modifications made the MK4R-A more reliable than the previous engine, despite the increase in power.
      However, there were still problems; significant vibrations occurred at certain altitudes and speeds; stiffening the engine mounts and propeller blades reduced these issues, but they were never fully solved (1). Another significant design flaw was identified in the summer of 1943; the shock absorber on the tail wheel could jam the elevator controls when the tailwheel retracted, making the aircraft virtually uncontrollable. This design flaw led to the death of one IJN pilot, and nearly killed two more (1). Ultimately, the IJN would not put the J2M2 into service until December 1943, 21 months after the first flight of the J2M1. 155 J2M2s would be built by Mitsubishi (3).
      By the time the J2M2 was entering service, the J2M3 was well into testing. The J2M3 was the most common variant of the Raiden, 260 were produced at Mitsubishi's factories (3). It was also the first variant to feature an armament of four 20mm cannons (oddly, of two different types of cannon with significantly different ballistics (2); the 7.7mm machine guns were replace with two Type 99 Model 1 cannons). Naturally, the performance of the J2M3 suffered slightly with the heavier armament, but it still retained its excellent rate of climb. The Raiden's excellent rate of climb was what kept it from being cancelled as higher performance aircraft like the N1K1-J Shiden came into service.

      The J2M's was designed to achieve a high climb rate, necessary for its intended role as an interceptor. The designers were successful; the J2M3, even with four 20mm cannons, was capable of climbing at 4650 feet per minute (1420 feet per minute) (2). Many fighters of World War 2, such as the CW-21, were claimed to be capable of climbing 'a mile a minute', but the Raiden was one of the few piston-engine aircraft that came close to achieving that mark. In fact, the Raiden climbed nearly as fast as the F8F Bearcat, despite being nearly three years older. Additionally, the J2M could continue to climb at high speeds for long periods; the J2M2 needed roughly 10 minutes to reach 30000 feet (9100 meters) (4), and on emergency power (using the methanol injection system), could maintain a climb rate in excess of 3000 feet per minute up to about 20000 feet (about 6000 meters).


      Analysis in Source (2) shows that the J2M3 was superior in several ways to one of its most common opponents, the F6F Hellcat. Though the Hellcat was faster at lower altitudes, the Raiden was equal at 6000 meters (about 20000 feet), and above that rapidly gained superiority. Additionally, the Raiden, despite not being designed for maneuverability, still had a lower stall speed than the Hellcat, and could turn tighter. The J2M3 actually had a lower wing loading than the American plane, and had flaps that could be used in combat to expand the wing area at will. As shown in the (poorly scanned) graphs on page 39 of (2), the J2M possessed a superior instantaneous turn capability to the F6F at all speeds. However, at high speeds the sustained turn capability of the American plane was superior (page 41 of (2)).
      The main area the American plane had the advantage was at high speeds and low altitudes; with the more powerful R-2800, the F6F could more easily overcome drag than the J2M. The F6F, as well as most other American planes, were also more solidly built than the J2M. The J2M also remained plagued by reliability issues throughout its service life.
      In addition to the J2M2 and J2M3 which made up the majority of Raidens built, there were a few other variants. The J2M4 was fitted with a turbo-supercharger, allowing its engine to produce significantly more power at high altitudes (1). However, this arrangement was highly unreliable, and let to only two J2M4s being built. Some sources also report that the J2M4 had two obliquely firing 20mm Type 99 Model 2 cannons in the fuselage behind the pilot (3). The J2M5 used a three stage mechanical supercharger, which proved more reliable than the turbo-supercharger, and still gave significant performance increases at altitude. Production of the J2M5 began at Koza 21st Naval Air Depot in late 1944 (6), but ultimately only about 34 would be built (3). The J2M6 was developed before the J2M4 and J2M6, it had minor updates such as an improved bubble canopy, only one was built (3). Finally, there was the J2M7, which was planned to use the same engine as the J2M5, with the improvements of the J2M6 incorporated. Few, if any, of this variant were built (3).
      A total of 621 J2Ms were built, mostly by Mitsubishi, which produced 473 airframes (5). However, 128 aircraft (about 1/5th of total production), were built at the Koza 21st Naval Air Depot (6). In addition to the reliability issues which delayed the introduction of the J2M, production was also hindered by American bombing, especially in 1945. For example, Appendix G of (5) shows that 270 J2Ms were ordered in 1945, but only 116 were produced in reality. (Unfortunately, sources (5) and (6) do not distinguish between different variants in their production figures.)
      Though the J2M2 variant first flew in October 1942, initial production of the Raiden was very slow. In the whole of 1942, only 13 airframes were produced (5). This included the three J2M1 prototypes. 90 airframes were produced in 1943, a significant increase over the year before, but still far less than had been ordered (5), and negligible compared to the production of American types. Production was highest in the spring and summer of 1944 (5), before falling off in late 1944 and 1945.
      The initial J2M1 and J2M2 variants were armed with a pair of Type 97 7.7mm machine guns, and two Type 99 Model 2 20mm cannons. The Type 97 used a 7.7x56mm rimmed cartridge; a clone of the .303 British round (7). This was the same machine gun used on other IJN fighters such as the A5M and A6M. The Type 99 Model 2 20mm cannon was a clone of the Swiss Oerlikon FF L (7), and used a 20x101mm cartridge.
      The J2M3 and further variants replaced the Type 97 machine guns with a pair of Type 99 Model 1 20mm cannons. These cannons, derived from the Oerlikon FF, used a 20x72mm cartridge (7), firing a round with roughly the same weight as the one used in the Model 2 at much lower velocity (2000 feet per second vs. 2500 feet per second (3), some sources (7) report an even lower velocity for the Type 99). The advantage the Model 1 had was lightness; it weighed only 26 kilograms vs. 34 kilograms for the model 2. Personally, I am doubtful that saving 16 kilograms was worth the difficulty of trying to use two weapons with different ballistics at the same time. Some variants (J2M3a, J2M5a) had four Model 2 20mm cannons (3), but they seem to be in the minority.

      In addition to autocannons and machine guns, the J2M was also fitted with two hardpoints which small bombs or rockets could be attached to (3) (4). Given the Raiden's role as an interceptor, and the small capacity of the hardpoints (roughly 60 kilograms) (3), it is highly unlikely that the J2M was ever substantially used as a bomber. Instead, it is more likely that the hardpoints on the J2M were used as mounting points for large air to air rockets, to be used to break up bomber formations, or ensure the destruction of a large aircraft like the B-29 in one hit. The most likely candidate for the J2M's rocket armament was the Type 3 No. 6 Mark 27 Bomb (Rocket) Model 1. Weighing 145 pounds (65.8 kilograms) (8), the Mark 27 was filled with payload of 5.5 pounds of incendiary fragments; upon launch it would accelerate to high subsonic speeds, before detonating after a set time (8). It is also possible that the similar Type 3 No. 1 Mark 28 could have been used; this was similar to the Mark 27, but much smaller, with a total weight of only 19.8 pounds (9 kilograms).
      The first unit to use the J2M in combat was the 381st Kokutai (1). Forming in October 1943, the unit at first operated Zeros, though gradually it filled with J2M2s through 1944. Even at this point, there were still problems with the Raiden's reliability. On January 30th, a Japanese pilot died when his J2M simply disintegrated during a training flight. By March 1944, the unit had been dispatched to Balikpapan, in Borneo, to defend the vital oil fields and refineries there. But due to the issues with the J2M, it used only Zeros. The first Raidens did not arrive until September 1944 (1). Reportedly, it made its debut on September 30th, when a mixed group of J2Ms and A6Ms intercepted a formation of B-24s attacking the Balikpapan refineries. The J2Ms did well for a few days, until escorting P-47s and P-38s arrived. Some 381st Raidens were also used in defense of Manila, in the Phillipines, as the Americans retook the islands. (9) By 1945, all units were ordered to return to Japan to defend against B-29s and the coming invasion. The 381st's J2Ms never made it to Japan; some ended up in Singapore, where they were found by the British (1).

      least three units operated the J2M in defense of the home islands of Japan; the 302nd, 332nd, and 352nd Kokutai. The 302nd's attempted combat debut came on November 1st, 1944, when a lone F-13 (reconaissance B-29) overflew Tokyo (1). The J2Ms, along with some Zeros and other fighters, did not manage to intercept the high flying bomber. The first successful attack against the B-29s came on December 3rd, when the 302nd shot down three B-29s. Later that month the 332nd first engaged B-29s attacking the Mitsubishi plant on December 22nd, shooting down one. (1)
      The 352nd operated in Western Japan, against B-29s flying out of China in late 1944 and early 1945. At first, despite severe maintenace issues, they achieved some successes, such as on November 21st, when a formation of B-29s flying at 25,000 feet was intercepted. Three B-29s were shot down, and more damaged.

      In general, when the Raidens were able to get to high altitude and attack the B-29s from above, they were relatively successful. This was particularly true when the J2Ms were assigned to intercept B-29 raids over Kyushu, which were flown at altitudes as low as 16,000 feet (1). The J2M also had virtually no capability to intercept aircraft at night, which made them essentially useless against LeMay's incendiary raids on Japanese cities. Finally the arrival of P-51s in April 1945 put the Raidens at a severe disadvantage; the P-51 was equal to or superior to the J2M in almost all respects, and by 1945 the Americans had much better trained pilots and better maintained machines. The last combat usage of the Raiden was on the morning of August 15th. The 302nd's Raidens and several Zeros engaged several Hellcats from VF-88 engaged in strafing runs. Reportedly four Hellcats were shot down, for the loss of two Raidens and at least one Zero(1). Japan surrendered only hours later.

      At least five J2Ms survived the war, though only one intact Raiden exists today. Two of the J2Ms were captured near Manila on February 20th, 1945 (9) (10). One of them was used for testing; but only briefly. On its second flight in American hands, an oil line in the engine failed, forcing it to land. The aircraft was later destroyed in a ground collision with a B-25 (9). Two more were found by the British in Singapore (1), and were flown in early 1946 but ex-IJN personnel (under close British supervision). The last Raiden was captured in Japan in 1945, and transported to the US. At some point, it ended up in a park in Los Angeles, before being restored to static display at the Planes of Fame museum in California.

      F6F-5 vs. J2M3 Comparison
      Further reading:
      An additional two dozen Raiden photos: https://www.worldwarphotos.info/gallery/japan/aircrafts/j2m-raiden/
    • By Belesarius
      Possible image of the H-20 bomber. Screengrab.  This will be the thread for the H-20 as more information becomes available.
      Anyone want to take a shot at translating what's on screen for us?
      Edit: This is a photoshop, as confirmed later in the thread where it was posted.
      But I'll keep the thread going for later stuff, and H-20 discussion.
    • By Alzoc
      Topic to post photo and video of various AFV seen through a thermal camera.
      I know that we won't be able to make any comparisons on the thermal signature of various tank without knowing which camera took the image and that the same areas (tracks, engine, sometimes exhaust) will always be the ones to show up but anyway:
      Just to see them under a different light than usual (pardon the terrible pun^^)
      Leclerc during a deployment test of the GALIX smoke dispenser:
      The picture on the bottom right was made using the castor sight (AMX 10 RC, AMX 30 B2)
      Akatsiya :


      A T-62 I think between 2 APC:




      Cougar 4x4:


  • Create New...