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LostCosmonaut

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  1. Metal
    LostCosmonaut got a reaction from Dragonstriker in Killing Pluto   
    Pluto has roughly the same surface area as Russia. Assuming that the American Minuteman III arsenal would be enough to "kill" something the size of Russia (Pluto has much less defenses than Russia, and their targets are probably less hardened against military attack), then we need 450 W87 warheads, which weigh about 250 kg each (I don't know the exact number). In other words,  112500 kg of warheads.
     
    The New Horizons probe weighed 478 kg and was launched on an Atlas V 551. 478 is pretty close to 250*2, so I'm going to say each Atlas V 551 can put two warheads on a Pluto intercept trajectory. This means we would need 225 Atlas Vs.
     
    74 Atlas Vs have been launched since 2002, just over 4.5 per year. However, given sufficient incentives and/or money, I'm going to conservatively assume ULA could double the production rate, to 9 rockets a year. Therefore, using the Atlas V, there are 225/9 = 25 years until we have enough rockets to kill Pluto. Add in the 9.5 year transit time (from the New Horizons mission), and if we start today, we could cleanse Pluto of life by the year 2043.
     
    With other rockets, like Falcon Heavy, SLS, or BFR, it's probable that we could throw more warheads per launch and reduce the number of rockets needed. However, the production rates of these launch vehicles, as well as their performance on a trans-Plutonian trajectory, is unknown. If we decide to go with something like an Orion drive that could get to Pluto quicker (and drop sufficient warheads in one go), we need to factor in research+development time, and I am not an expert at those sorts of things.
     
    For a more extreme case, if we want to completely erase Pluto from existence, it will be harder. Pluto has a mass of 1.31*10^22 kg. To disperse this mass, I will assume we need to accelerate it to Pluto's escape velocity. From wiki, escape velocity is given by the following formula;
     

     
    (side note, I'm going to say r is the radius where half the volume of Pluto is outside that radius. This is (1/2)^(1/3) times Pluto's radius, which is .7397*1188 km = 878.8 km = 8.788*10^5 m).
     
    Solving for escape velocity, we find that the escape velocity is 1410 m/s. Therefore, the kinetic energy needed is .5 * 1.31*10^22 kg * (1410 m/s)^2 = 1.30*10^28 J. According to the Atomic Rockets page, the Sun puts out 3.9*10^26 J per second (watts). Therefore, we need to harness 33 seconds of the Sun's output and focus it simultaneously on Pluto. This is well beyond the technical capabilites of our civilization at the present time.
     
     
     
  2. Tank You
    LostCosmonaut got a reaction from Stimpy75 in J2M Raiden   
    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;
     
    (Airspeed*(Thrust-Drag))/Weight
     
     
     
    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.
     
     

     
     
    Sources:
     
     
    https://www.docdroid.net/gDMQra3/raiden-aeroplane-february-2016.pdf#page=2
    F6F-5 vs. J2M3 Comparison
    http://www.combinedfleet.com/ijna/j2m.htm
    http://www.wwiiaircraftperformance.org/japan/Jack-11-105A.pdf
    https://babel.hathitrust.org/cgi/pt?id=mdp.39015080324281;view=1up;seq=80
    https://archive.org/stream/corporationrepor34unit#page/n15/mode/2up
    http://users.telenet.be/Emmanuel.Gustin/fgun/fgun-pe.html
    http://ww2data.blogspot.com/2016/04/imperial-japanese-navy-explosives-bombs.html
    https://www.pacificwrecks.com/aircraft/j2m/3008.html
    https://www.pacificwrecks.com/aircraft/j2m/3013.html
    https://www.pacificwrecks.com/aircraft/j2m/3014.html
     
     
    Further reading:
     
    An additional two dozen Raiden photos: https://www.worldwarphotos.info/gallery/japan/aircrafts/j2m-raiden/
     
     
  3. Tank You
    LostCosmonaut got a reaction from Domus Acipenseris in MiG-25 Foxbat Information Thread (work in progress)   
    Basic History
    State of PVO before MiG-25

    During the middle part of the 1950s, the PVO (Soviet air defense forces) were poorly equipped to deal with future threats. The majority of its interceptors consisted of aircraft such as the MiG-15, MiG-17, MiG-19, and Yak-25. These aircraft possessed sufficient performance to take on American bombers such as the B-29 and B-50, and were at least marginally capable of intercepting jets like the B-47 or B-52. However, they were horribly inadequate against coming bombers, such as the B-58 Hustler (which first flew in 1956).

    The arrival of Mach 2 capable interceptors such as the Su-9, and later the MiG-21 in the latter portion of the 1950s evened the playing field somewhat. However, these interceptors suffered from severe deficiencies. The Su-9 (and to a lesser extent the MiG-21) had a cripplingly short range, a major shortcoming when defending a country as large as the Soviet Union. The Yak-27, a development of the Yak-25, had better range than either of the deltas, but was inferior in terms of speed and altitude. In addition to various performance issues, the PVO’s interceptors were also handicapped by poor armaments. The Kaliningrad K-5 (NATO AA-1) radar guided missile was equipped by most PVO interceptors following its introduction in 1955. Though decent for its time, it was limited by its beam riding guidance and short range. The infrared guided K-13 (AA-2) was introduced in 1960 after being hurried copied from a captured AIM-9B. Like the K-5, the K-13 suffered from poor range, and was also limited to being fired at the rear of a target.

    These systems would clearly not be sufficient to reliably destroy the B-58, let alone the Mach 3 capable XB-70 (which began development in the late 1950s). The introduction of surface to air missiles such as the S-25 and S-75 had some promise (as demonstrated by the destruction of a U-2 reconnaissance aircraft by an S-75 on May 1 1960 at over 18,000 meters). However, these missiles required large fixed launch sites, leaving them incapable of covering large swaths of territory. In an environment where a single bomber was capable of destroying a whole city, the situation was clearly unacceptable. It was clear that a new interceptor was needed to equip the PVO.

    Numerous solutions were tried. A modified variant of the MiG-19, the MiG-19SU was tested. This aircraft was fitted with liquid rocket engines in addition to the two RD-9s, giving (briefly) improved speed and altitude capability. This allowed flights to over 20,000 meters , however, the aircraft suffered severe controllability issues. In any case, it was clearly a temporarily solution. Another program was the development of various ‘heavy interceptors’, capable of engaging NATO bombers at extreme range, well away from populated areas or strategic targets. These included the abortive La-250, and more successful Tu-128 (developed from the Tu-98 bomber prototype). Though the Tu-128 entered service (indeed, it continued on into the early 1990s), it did not arrive until the middle of the 1960s. Even then, it was a large and ponderous aircraft, capable only of transonic speeds and completely lacking maneuverability.  It could not serve as the PVO’s primary interceptor.

    An effort with more potential was the Sukhoi T-37. This aircraft was broadly similar in planform to the Su-9 (being a tailed delta) but was much larger. Powered by an R-15-300 engine, it was planned to reach speeds near 3,000 km/h at altitudes approaching 25,000 meters. Interestingly, it was also to have been fitted with equipment enabling it to be flown automatically under ground control (the US had the SemiAutomatic Ground Environment, a similar system capable of directing F-106s). However, it was plagued by numerous issues, and was scrapped in 1960 before it ever flew.

    Requirements
    The requirements for the MiG-25 were greatly determined by its potential adversaries. The main threat was the B-58 Hustler, capable of Mach 2 at altitudes approaching 18,000 meters. In 1960, the Soviets became aware of yet another threat; a Mach 3 successor to the U-2 was under development (this was the A-12/SR-71, though the Soviets did not know this initially).  As a result, it was decided that the new interceptor should be capable of flight at up to Mach 3, and at altitudes in excess of 20,000 meters.

    Coincidentally, the VVS (Soviet Air Force, separate from air defense forces) was looking for a new high speed reconnaissance aircraft during the late 1950s. At the time, most of the VVS reconnaissance force consisted of variants of the Il-28 or Yak-25. The survivability of these aircraft against new NATO fighters such as the F-104 or Lightning was marginal at best. The Yak-25RV was in development, and promised comparable performance to the U-2 (it did not fully deliver), but this was an incremental step at best. A wholly new aircraft with exceptional performance was needed. By 1960, it was realized that the new recon aircraft had broadly similar requirements to the new PVO interceptor program (by then in development for over a year), so the programs were merged. The ability to carry photorecon equipment was added as a requirement to the interceptor program.

    Development
    The Ye-150/152 can be considered the direct ancestor of the MiG-25. Developed in the late 1950s and first flying in 1960, the Ye-150 was broadly similar in appearance to the MiG-21, but was significantly larger and was capable of reaching much higher speeds. The Ye-152 was a further development; it was fitted with R-15-300 engines, the same R-15s which would be fitted to the MiG-25. Like the Ye-150, it represented a massive performance leap over the MiG-21, but it was very much a testbed. The R-15s were supremely unreliable (early models had an average engine lifetime of roughly 20 hours), and the weapons system was tempermental. There was also the Ye-152A, which was fitted with two R-11 turbojets (the same engine as the MiG-21) instead of a single R-15. Though these aircraft did not enter production, they provided the Mikoyan-Gurevich design bureau with valuable data on high speed flight and the R-15 engine.

    There is some uncertainty about the initial genesis of the MiG-25 program. There are rumors that Mikoyan instructed chief designed Seletisky to develop an interceptor similar to the North American A-5 Vigilante (which had first flow in late 1958) powered by two R-15-300s. Other sources state that work began before the first flight of the A-5. While there are obvious similarities in layout between the A-5 and MiG-25, there are also massive differences. At most, the MiG-25 was somewhat inspired by the A-5, and is very much not a ‘clone’ or reverse engineered copy. (Later proposed Vigilante derivatives such as the NR-349 or rumored J58 powered version would have been much more analogous to the MiG-25).

    The new aircraft was assigned the designation Ye-155 by Mikoyan (the prefix Ye for yedinitsa denoting a prototype or testbed aircraft). It was decided very early to use the R-15-300 engine. However, there remained uncertainty as to the layout of the engines. Though a conventional side by side layout was ultimately chosen, a vertically stacked layout (such as on the English Electric Lightning) was also considered, as was a staggered engine arrangement (as on the I-320 prototype). Unlike previous Mikoyan-Gurevich designs, it was decided not to utilize a nose mounted intake, but instead place the intakes under the wings. This allowed for a smaller fuselage (in both length and cross section). The underwing intake placement worked well with the shoulder mounted wing placement, which was needed to allow for the carriage of very large AAMs. This wing layout also allowed the wings to be constructed in one piece, simplifying constructing and improving structural rigidity.

     

    Numerous planforms were proposed for the wing before the design of the prototype was finalized. At one point variable geometry designs were considered (this would have significantly predated the introduction of the Su-17, though variable sweep designs had been studied at least since 1945). The variable sweep design was seriously considered enough that a model of a recon MiG-25 with variable geometry was made, it somewhat resembles an F-14. One of the benefits of the variable geometry design would have been improved takeoff and landing performance, however, it was decided that this was not worth the added complexity and weight associated with such a design. Following numerous wind tunnel tests, a trapezoidal wing of low aspect ratio was chosen.

     

    As with many Soviet designs in the 1950s and 1960s, lift jets were considered for use to improve takeoff and landing distance. The proposed STOL design would have used two small RD36-35 lift engines, mounted in a slightly staggered arrangement in the fuselage, with intakes along the back of the aircraft. While the lift jets would likely have improved takeoff and landing distances greatly, they also decreased the internal volume available for fuel. This was a serious drawback, especially for the reconnaissance version. As a result, the lift jets were discarded, with the STOL design not progressing beyond the model stage.

     

    As the MiG-25’s design grew closer to being finalized, materials selection became a serious issue. The leading edges of the wings, inlets, and nose of the aircraft would experience extremely high temperatures at Mach 3, well above the melting point of conventional aluminum alloys commonly used in aircraft construction. Alternative materials had to be found, and many were considered. At first, titanium seemed a logical choice. It has excellent thermal properties, is quite strong for its weight, and the Soviet Union possessed large reserves of the material. However, the Soviet aircraft industry had little experience working with titanium, which was notoriously temperamental (for instance, when manufacturing the SR-71, Lockheed engineers were forced to use special tools, as normal tools contained cadmium, which made the titanium brittle). In particular, the automated welding methods commonly used in Soviet aircraft manufacturing plants would not be suitable for titanium. As a result, it was decided to use steel alloys for the majority of the MiG-25s structure (titanium was used in some areas, but at much lower quantities). Initially, there were some doubts as to whether certain components (such as the integrated fuel tanks) could be made strong enough without seriously increasing weight, or absorbing the cyclical flight loads. Tests showed that this was not the case, and the MiG-25 ended up being built using large quantities. In addition to the issues with materials selection for the aircraft structure, the thermal loads associated with high speed flight caused trouble in other areas. Normal lubricants and hydraulic fluid would break down at the temperatures the MiG-25 would experience, and normal canopy glass would melt. In many ways, this mirrors the problems faced by the Skunk Works team designing the A-12 at around the same time.

     

    Throughout 1962 and 1963, the design of the MiG-25 was further refined. In 1963, construction began on the first prototype, Ye-155R1. Its completion took most of the year, and it was not rolled out from the Zenit Machinery Works (the common name for the MiG bureau’s experimental aircraft factory) until December. Despite this, Ye-155R-1, a prototype of the reconnaissance variant, was missing much of its operational equipment. Still, it had more than enough to validate the basic flight characteristics of the airframe.

     

    In addition to lacking various pieces of equipment, Ye-155R-1 differed from production MiG-25s in several ways. For one, the aircraft had a pair of 600 liter fuel tanks mounted at the wingtips. These both increased fuel capacity, and prevented flutter. Ventral fins were attached to the fuel tanks, to improve lateral stability at high speeds. Both of these features would be absent from production MiG-25s. Ye-155R-1 also had provisions for the fitment of canards to the sides of the forward portion of the air intakes; these would have been used for pitch control at high Mach numbers, but they were never installed.

     

    The first prototype suffered from numerous issues. Among the most serious of these was roll control issues in the transonic regime, in some cases severe enough to render the aircraft uncontrollable. The wingtip fuel tanks caused vibration as fuel was depleted and sloshed about. The intakes were inefficient at high Mach numbers, and the aircraft’s static margin decreased as well. Finally, Ye-155R-1 was overweight, causing its range to fall short of the target.

     

    The second prototype, Ye-155R-2, was also a prototype of the recon MiG-25. This aircraft was broadly similar to the previous prototype, though it did incorporate some refinements. There was one immediately obvious difference; the wingtip fuel tanks were deleted. This would be the last prototype built at the Zenit plant; the factory was tasked with producing the first MiG-23 prototypes, and had no more room for further Ye-155s. As a result, it was decided to build prototypes from Ye-155R-3 onward at Mikoyan’s Gorkii plant, the same as would produce the production aircraft. This resulted in a delay in producing Ye-155R-3 as the factory was retooled, but it would ultimately allow production to commence quicker. Ye-155R-3 was a milestone in and of itself; it was fitted with a full suite of photorecon equipment, and would be used for testing various camera arrangements (among other things).

    Belenko Defection
    Later Variants
    Post-Soviet service
    Variants
    Prototypes
    Ye-155 models

    Operational
    MiG-25P/PD/PDS
    Export MiG-25P

    MiG-25RB
    MiG-25R
    MiG-25BM
    MiG-25PU

    Other
    Ye-266M
    Ye-155MP
    Buran testbeds / training aircraft
    Various other concepts and variants


    Production
    In Red Air Force Service
    Other Operators
    Combat Performance
    Egypt vs. Israel
    Iraq
    MiG-25 vs. SR-71

    Structure
    Materials

    Engines
     

    Electronics
    Radar
    Early versions vs. Later

    Recon variants - cameras

    Armaments
    Air to Air
    MiG-25P
    MiG-25PD

    Ground
    MiG-25RB
    MiG-25BM


    Other Systems of Note
    Citations
    http://www.kamov.net/russian-aircraft/mig-19su/
    http://www.kamov.net/russian-aircraft/sukhoi-t-37/
    MiG-25 'Foxbat', MiG-31 'Foxhound': Russia's defensive front line By: Gordon, Yefim. Aerofax 1997
    Skunk Works: a personal memoir of my years at Lockheed By: Rich, Ben R., and Leo Janos. Little, Brown 1994

  4. Tank You
    LostCosmonaut got a reaction from Domus Acipenseris in Aerospace Documents Collection Point   
    Project 1794 (Avrocar) Final Report
    Sonic Cruiser Concept Analysis
    Span-Distributed Loading Cargo Aircraft
  5. Tank You
    LostCosmonaut got a reaction from Beer in The Yakovlev VTOL Family   
    During the latter part of the Cold War, the Yakovlev design bureau came up with quite a few designs for VTOL combat aircraft. While they weren't the most successful designs, they are pretty interesting, from both a historical and technical standpoint.
     
    The first of these is the Yak-36 (Freehand);
     

     
    While the Soviets had come up with numerous other VTOL designs in the 1960s, most of them used dedicated vertically mounted engines to take off vertically. However, the Yak-36 had a more modern arrangement, with two engines that used vectored thrust for both vertical and horizontal flight. The Yak-36 was powered by a pair of R27-300 jet engines (the same engines that powered the MiG-23 'Faithless' VTOL concept). In addition to providing vertical and horizontal thurst, the engines also provided airflow for 'puffers' at the wingtips, nose, and tail, which provided control in hover and low speeds (where aerodynamic controls would not be effective).
     
    The Yak-36 suffered from various difficulties during its development, among them the engines reingesting exhaust gases. At least two of the prototypes crashed at somepoint. Though the Yak-36 was at various points displayed with underwing armaments (such as rocket pods), it was never deployed to operational units; it was solely used as a testbed.
     
    Following the Yak-36 was the more widely known Yak-38 (Forger). It entered service in the early 1980s.
     

     
    Unlike the Yak-36, the Yak-38 was fitted with lift jets (two RD-36V engines). Though these engines did an adequate job of providing vertical lift, they had the drawback of being dead weight in horizontal flight. Horizontal thrust was provided by  a single R27-300. Though the Yak-38 was capable of VTOL, it had highly limited performance; it was strictly subsonic, and had marginal payload capability.
     

    (pictured: unrestrained optimism)
     
    The Yak-38 was designed from the outset as a combat aircraft, intended to be deployed from the Soviets' Kiev class carriers. In this role, it was shit (much like your favorite anime). The first issue was reliability; many of the Forger's components proved to be horrendously unreliable, especially the lift jets. I've seen figures stating that the lift jets had an average lifetime of less than 25 hours, which leads me to suspect they were actually rebranded Jumo 004s. Engine failures were especially bad in the Yak-38 - a failure of a lift jet on one side would lead to the jet entering a fast, unrecoverable roll. The lift jets also had poor thrust in hot conditions; in many cases, the Yak-38 had to fly with only two pylons filled, rather than all four. Considering that the Yak-38 had no internal armament, this was not optimal. Interestingly, in addition to using it as a carrier aircraft, the Soviets also trialed the Yak-38 as a close air support in Afghanistan. This was less than successful; the Yak-38 was only capable of carrying a pair of 100kg bombs, markedly inferior to dedicated CAS aircraft such as the Su-25.
     
    Rumors of the Yak-38 being deployed to Colorado are false;
     

     
    Numerous variants of the Yak-38 were developed, most notably the Yak-38M, which despite having improved engines and other components, was still a dog. There was also the Yak-38U, a serious contender for the title of 'Ugliest Airplane'.
     
     
    In the late 1970s, development of a successor to the Yak-38 began. This aircraft was the Yak-41 (Freestyle).
     

     
    The general configuration of the Yak-41 was similar to the Yak-38, with a pair of lift jets in the fuselage and a single main engine for thrust. However, its capabilities were massively improved. While the Yak-38 was a strictly subsonic aircraft, the Yak-41 was capable of supersonic flight, setting many records for VTOL aircraft (under the fictional designation Yak-141). Additionally, it incorporated far more advanced materials in its structure (including large scale use of composites), as well as improved avionics (such as a radar set which was actually useful). Its payload capacity, in terms of weight, was roughly the same as what the Yak-38 could (theoretically) carry. However, given that the Yak-41 was a dedicated air superiority craft, this was less of a concern than the Yak-38s payload deficiency in the strike role.
     

     
    Unfortunately for the Yak-41, it began testing in the late 1980s, just as the Soviet Union was falling apart. Though some testing continued through the early 90s, the Yak-41 never entered operational service. The second nail in the Yak-41s coffin was the Soviet Union / Russian Federation's acquisition of larger aircraft carrier(s), capable of operating aircraft such as the Su-27K and MiG-29K.
     
    Interestingly, for a few years in the early 1990s, Yakovlev collaborated with Lockheed Martin on the development of the Yak-41. This has given rise to many conspiracies about the F-35B being a clone of the Yak-41. While this is obviously false, it wouldn't be outside the realm of possibility that a few bits on the JSF might have drawn inspiration from Yak's design in some way.
     
    There was one final successor to the Yak-41; the Yak-43. An even more advanced evolution, the Yak-43 could have been quite capable (had it been built). From what I can find, it dispensed with the extraneous lift jets. Power would have been provided by a modified NK-32 turbofan, the same engine that powers the Tu-160. This would have given the Yak-43 significantly improved performance and payload capacity compared to its predecessors. Additionally, the Yak-43 would have incorporated low observability features into its design, bringing it closer to being a true competitor to aircraft such as the F-35B. In any case, the aircraft remained unbuilt, and I have not heard of any efforts to revive the design.
     

     

     
     
  6. Tank You
    LostCosmonaut got a reaction from Domus Acipenseris in J35 Appreciation Station   
    More stuff stolen from SA: low speed characteristics of J37; http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19860019453.pdf
  7. Tank You
    LostCosmonaut got a reaction from T80U :DDDDDDDDDDD in Bash the F-35 thred.   
    From AH dot com, of all places (apparently the one competent poster)
     
    Also, the F-35's IR sensors are pretty good;
     

  8. Funny
    LostCosmonaut got a reaction from Alex in BlackTailDefense Doesn't Know Shit About Tank Design   
    welp, not even SH is safe from being linked to furry porn
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    LostCosmonaut got a reaction from Dragonstriker in The Designer of The 6.8 SPC Rants About The 7mm Caliber   
    If you aim for the stars and miss, you'll still hit the moon die in the cold, unforgiving vacuum of space.
  10. Tank You
    LostCosmonaut reacted to Mogensthegreat in Aerospace Pictures and Art Thread   
    My grandfather's F-86 Sabre that he flew in Korea and shot down a Mig-15 in, his was #881, in the front of the picture.
  11. Tank You
    LostCosmonaut reacted to renhanxue in J35 Appreciation Station   
    If you were indecisive about buying a Draken, this 1960 Australian evaluation of the J 35B might help you make your decision (does breaking the sound barrier in level flight with dry thrust only sound appealing to you?). Relevant documents start on page 74, report from the test pilot starts on page 87. The same file also contains at least a partial eval of the Mirage III.
  12. Tank You
    LostCosmonaut reacted to LoooSeR in Aerospace Pictures and Art Thread   
    1st gen and 4.5 gen jet fighters
     
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    LostCosmonaut reacted to LoooSeR in Aerospace Pictures and Art Thread   
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    LostCosmonaut got a reaction from LoooSeR in Documents for the Documents God   
    Mines Yesterday, Today, Tomorrow (untranslated)
  15. Tank You
    LostCosmonaut got a reaction from Belesarius in Aerospace Pictures and Art Thread   
    Some hypersonics related stuff found on the internet.
     



     

     
  16. Tank You
    LostCosmonaut reacted to A_Mysterious_Stranger in Shape of APFSDS's core   
    I don't think you're going to get a neat, single answer for all of this.  Penetration is very complicated even when you focus only on rigid OR eroding regimes.   APFSDS occupy a transitional region between those two, meaning it is likely to be even more complex. 
     
    For example I did more digging by changing search parameters.  One thing I turned up came from army-guide and this interesting point:
     


     
    Completely unsourced but it shows a the potential for multiple factors at work.    I've found sources that allude to nose shape influencing interface defeat, transitions from rigid to eroding penetration and velocity thresholds, and so on.  I'll share the various things I ran across in the hopes it will prove useful.  In no particular order:
     
    CTH hydrocode predictions on the effect of rod nose-shape on the velocity at which tungsten alloy rods transition from rigid body to eroding penetrators when impacting thick aluminium targets
     
    Abstract:


    Design of hard-target penetrator nose geometry in the presence of high-speed, velocity-dependent friction, including the effects of mass loss and blunting
     
    Abstract


     
    INTERIOR AND TERMINAL BALLISTICS OF 25g LONG ROD PENETRATORS
     
    Introduction:



    Investigation of Oblique Penetration I: The Effects of Penetrator Leading End Shapes on Unyawed and Yawed Impacts
    Abstract



    TERMINAL BALLISTICS TEST AND ANALYSIS GUIDELINES FOR THE PENETRATION MECHANICS BRANCH
     
    Introduction:


     
    Penetration of 6061-T6511 aluminum targets by ogive-nosed VAR 4340 steel projectiles at oblique angles: experiments and simulations
    Abstract



    The Effect of Nose Shape in Long Rod Penetration
    (link to free PDF download)
    Abstract:


     
    This one seems related to the one below, so I included it more for completion's sake and informative purposes. 
     
    Comparative Study of Nose Profile Role in Long-Rod Penetration
    Abstract:


     
    Honestly I'm not sure this is very relevant.  It seems more about eroding-penetrator processes and mushrooming vs non-mushrooming.  But it's also about EM guns specifically, so it was worth mentioning.
     
    Interface Defeat of Long-Rod Projectiles by Ceramic Armor
    Abstract:


     
    This is mostly about interface defeat in general vs ceramics, but there is a bit in there about nose shape.  So nose shape may be a factor here.
     
    Interface defeat studies of long-rod projectile impacting on ceramic targets
     
    Abstract:


     
    Analysis of the Noneroding Penetration of Tungsten Alloy Long Rods Into Aluminum Targets
    Abstract



     
    This one seems to be more about rigid penetration, but its also about about LRPs. Worth noting for that 'transitional' aspect I mentioned and the fact nose shape has a huge impact in rigid penetration.
     
    Modeling Threshold Velocity of Hemispherical and Ogival-Nose Tungsten-Alloy Penetrators Perforating Finite Aluminum Targets
    Abstract

  17. Tank You
    LostCosmonaut reacted to A_Mysterious_Stranger in Shape of APFSDS's core   
    What I could find: 
    Jacketed Long-Rod Penetrators: Problems and Perspectives
     
     
    Though that is about Jacketed Penetrators, it seems it may still apply to regular APFSDS.  Given it cites Rosenberg and Deckel you might look at their work 'Terminal Ballistics' for more information. 
     
    Possibly more useful is this: 
     
    The Effect of Nose Shape on Depleted Uranium (DU) Long-Rod Penetrators
     
    I apologize for not quoting any of this, but its a 66 page non searchable PDF, and I'm not sure that you can just select parts without reading the whole thing for context since it's specifically about LRP and nose shape for DU rounds (some tungsten is mentioned.) 
     
    Also of possible interest are these reddit posts.  I'm not sure how 'good' it is since we're talking War Thunder (I'm as wary of that as I am of WoT based research) but I figure I'd include it for completeness sake and potential for discussion: 
     
    APFSDS the Science of Ricochets
     
    How tip shapes affect APFSDS performance on sloped armour
     
    I also believe that most APFSDS don't operate fully in the eroding (hydrodynamic) regime and would slow down on impact anyhow.  So rigid penetration effects may apply (nose shape does matter quite a bit there).
     
    Lastly because it may be of interest to someone materials which may be of interest but may not be relevant to the discussion:
     
    Penetrator strength effect in long-rod critical ricochet angle
     
    Interaction between High-velocity Penetrators and Moving Armour Components
     
    PENETRATION OF METALLIC PLATES BY KINETIC ENERGY PROJECTILES
     
    The Relation Between Initial Yaw and Long Rod Projectile Shape after Penetrating an Oblique Thin Plate
  18. Tank You
    LostCosmonaut got a reaction from Beer in Advanced MiG-3 Variants   
    Intro
     

    The MiG-3. All flying aircraft today have been re-engined with the V1710, and look slightly different.
     
    The MiG-3 was one of the first fighters developed by the famous Mikoyan-Gurevich design bureau. An improvement on the troubled MiG-1, the MiG-3 was designed for combat at high altitude. Introduced in 1941, it gained less fame than its contemporaries like the Yakovlev and Lavochkin fighters. Germany's virtually nonexistent strategic bomber force, and the low-altitude nature of combat on the Eastern Front meant the MiG-3 was forced out of its element, and its performance suffered. Combined with the MiG's difficult flight characteristics and the horrible strategic situation for the Soviets in 1941, this meant the MiG-3 achieved little success.
     
    While the MiG-3 did not spawn a successful series of fighters (like the Yak-1, Yak-9, and Yak-3, for instance), numerous variants were considered, and many of them were built in at least prototype form. However, for many reasons, such as lack of need or nTheonavailability of suitable engines, none of these variants entered large scale production.
     
     
     
     
    I-230/MiG-3U
     

    The resemblance to the baseline MiG-3 is easily seen. via aviastar
     
    The I-230 was one of the more straightforward developments of the MiG-3. Development on the I-230 (also known as the MiG-3U) began in late 1941, with the objective to correct numerous flaws identified in the MiG-3. First was the armament; the MiG-3 had only two 7.62mm ShKAS machine guns and a single 12.7 Berezen (BS) machine gun, firing through the propeller. On the I-230, these were replaced with two 20mm ShVAK cannons (again synchronized to fire through the propeller).
     
    Outwardly, the I-230 looked very similar to the production MiG-3, although the new aircraft was made mostly of wood instead of steel tubing and duralumin. The wing area and wingspan were increased (to 18 m^2 and 11 meters, versus 17.4 m^2 and 10.2 meters for the production MiG-3), and the fuselage was lengthened by .37 meters.
     
    Soviet engineers originally intended to fit the I-230 with the AM-39 engine. However, by the time the I-230 airframe was completed in early 1942, the AM-39 was not yet available. As a result, the first I-230 was forced to use an engine built from both AM-38 and AM-35 parts (designated AM-35A). This engine was roughly 40 kilograms heavier than the intended engine, but produced a respectable 1350 horsepower. Even with such an odd engine, the I-230 flew by the end of 1942, achieving a top speed of over 650 km/hr at altitude. (Some sources say the I-230 first flew in May 1943, this is likely for the machines with AM-35A engines). Four more prototypes were built with AM-35A engines. These aircraft would serve in defense of the Moscow region while undergoing flight testing. While the design showed promise, by this point the AM-35 was obsolete and out of production. Additionally, some other deficiencies were identified. The I-230 was found to be difficult to land (a flaw shared with the MiG-3), and the engine tended to leak oil into the rest of the aircraft at high altitudes. As a result, the I-230 was not built.
     
    I-231
     
    The I-231 was a further evolution of the I-230, using the AM-39 engine that had originally been intended for use in the I-230. One of the I-230 aircraft had its engine replaced with the more powerful AM-39. This required modification of the cooling system; the radiator was enlarged, with another secondary radiator installed. There were also a few other modifications, such as moving the horizontal tail surfaces downward slightly, the fuselage fuel tank was enlarged and some modifications to the radios. Armament was the same as the I-230; two 20mm ShVAK cannons.
     
    First flight of the I-231 was in October 1943. However, in early November, the prototype was forced to make an emergency landing after the supercharger failed at high altitude. Two weeks later, flight testing of the repaired I-231 resumed. The prototype, with the more powerful AM-39 (1800 horsepower), reached a top speed of 707 km/hr at an altitude of about 7000 meters. It also climbed to 5000 meters in under 5 minutes. Flight testing continued in early 1944, and in March, the I-231 was damaged after overrunning the runway during landing. The program suffered another setback when the repaired I-231 suffered an engine failure, damaging the precious AM-39 engine. Following this last mishap, work on the I-231 was discontinued.
     
     

    The similarities between the radial and inline engined models are still visible. via airvectors
     
    I-210/MiG-9 M-82
     

    I-210 with radial engine. via airpages.ru
     
    The I-210 was a more substantial modification of the MiG-3 which began in the summer of 1941. Production of the Shvestsov M-82 radial engine had recently begun, and many design bureaus, including MiG, were instructed to find ways to incorporate the engine into their designs. In the case of the MiG-3, this was especially important, as the Soviet government sought to discontinue the AM-35 to free up production space for the AM-38 used by the all-important Il-2.
     
    In theory, the M-82, with 1700 horsepower, would provide a significant performance increase over the AM-35. Soviet engineers projected that the M-82 equipped MiG-3 (now known as the I-210) would reach nearly 650 km/hr at altitude. It was also projected that performance would be massively improved at low altitude, important for combat on the Eastern Front. The new aircraft was received the designation “MiG-9 M-82”, denoting that it was a substantially new type (this designation would later be reused for a twin-jet fighter in the late 1940s).
     
    In addition to fitting of the M-82, there were several other differences between the MiG-3 and the I-210. Armament was increased to three 12.7mm UBS machine guns (two 7.62mm ShKAS were fitted initially, but soon removed). Several systems related to the engine, including the oil coolers and fuel system were also updated. The fuselage was widened slightly to accommodate the new engine.
     
    The I-210 first flew in July 1941. However, it became quickly apparent that it was not meeting its performance targets. The top speed at an altitude of 5000 meters was a mere 540 km/hr, far inferior to to projects (as well as the production MiG-3!). Part of this was due to having a different model of propeller installed than what was intended. However, wind tunnel testing and inspection showed that the engine cowling was poorly designed and sealed to the rest of the airframe, causing significant drag.
     
    Several months were required to correct the various defects, and it was not until June 1942 that three I-210s were ready for trails. During testing, the three aircraft were assigned to the PVO for use on the front. State trials began in September, and the I-210 fared poorly. Maximum speed was still only 565 km/hr, far inferior to existing types. Overall, the I-210 was judged to be unsatisfactory and inferior to the La-5 and Yak-7. The aircraft did not enter production, although the three completed prototypes would serve in Karelia until 1944.
     
    I-211/MiG-9E
     
    The failure of the I-210 was not the end of efforts to install a radial engine into the MiG-3 airframe. In late 1942, work on the I-211 began. A new Ash-82 engine, an improved variant of the M-82 installed on the I-210, was fitted. With the help of the Shvetsov bureau, the aerodynamics of the engine and its cowling were substantially improved. Further modifications reduced the empty weight of the “MiG-9E” by 170 kg. The three 12.7mm machine guns were replaced by two 20mm ShVAK cannons.
     
    Testing of the I-211 began in August 1942 (other sources variously say that testing did not begin until early 1943, my interpretation is that this is when state trials officially happened). Performance was markedly superior to the I-210; the I-211 reached a top speed of 670 km/hr, and was able to climb to altitudes in excess of 11000 meters. However, the La-5, which was already in production using the M-82 engine, had similar performance. Moreover, the La-7 was in development, and was felt to have better potential. In all, only ten I-211s were built.
     
    Interestingly, at least one source claims that a variant of the I-211 equipped with a Lend-Lease R-2800 engine was considered. There is no evidence that such an aircraft was actually built.
     
     
    I-220/MiG-11
     
    The I-220 (and the rest of its series up to the I-225) were substantially different from the production MiG-3, sharing little aside from the basic design and concept. These aircraft took the original mission of the MiG-3, interception of targets at high altitude, to the ultimate extreme.
     
    The initial request that led to development of the I-220 was issued in July 1941, in response to high-altitude overflights by Ju-86P reconnaissance aircraft. These aircraft, capable of operating at over 13000 meters, were outside the reach of almost any Soviet fighter. A few Ju-86Ps at slightly lower altitude were intercepted by MiG-3s before the start of the war, so the MiG-3 was a natural starting point for a high-altitude interceptor.
     
    Work on the I-220 prototype began in late 1942. Originally, it had been planned to install the AM-39 engine, but it was not ready at the time construction began on the prototype. Instead, one source (OKB MiG, Page 48) states anAM-38F engine was installed, which still provided more power (1700 hp) than the AM-35 on the MiG-3. However, it had the drawback of losing power at high-altitudes; the AM-38F would be an interim installation at best. A different source reports that an AM-37 was the first engine installed.
     
    In addition to the new engine, the wingspan was lengthened by .80 meters, with a slight sweep added to the outer portion of the leading edge. The radiator was relocated from the belly of the aircraft to inside the wing center section, with new air intakes added at the wing roots. Armament was increased to four ShVAKs, making the I-220 one of the heaviest armed Soviet fighters.
     
    The I-220 first flew in January 1943. Testing of the aircraft proceeded, as the AM-39 was still not yet ready. Despite being handicapped by the AM-38F engine, the I-220 prototype was still able to reach 650 km/hr during testing in January 1944. It was agreed that the aircraft had potential, but would need the AM-39 to reach its maximum performance. The second I-220 prototype was eventually fitted with the AM-39, but by that point it had been decided to substantially redesign the aircraft.
     
     
     

    I-220 vs. I-221
     
    I-221/MiG-7
     
    While the I-220 had done well, it had not been able to reach the altitudes its designers had hoped for. Numerous changes would be required to get the best possible performance out of the airframe.
     
    The most obvious area for improvement was the engine. Rather than the AM-38F, an AM-39A with a turbocharger was installed. Not only was the AM-39 more powerful than the AM-38, but the twin turbocharger would allow the engine to continue developing power at altitude. Additionally, the wingspan was increased further, to 13 meters. Armament was reduced to two ShVAK cannons, to save weight. Significantly, the I-221 was fitted with a pressurized cockpit, to allow the pilot to survive at extreme altitude.
     
    By the time the I-221 made its first flight in December 1943, the Ju-86 threat had disappeared. One of the high-altitude intruders had been intercepted by a Yak-9PD (a high-altitude version of the Yak-9 designed and built in three weeks), though it had not been destroyed, overflights ceased. Nevertheless, the Yak-9PD was very much an interim solution, armed with only one ShVAK and requiring 25 minutes to climb to 12000 meters. So, development of the I-221 continued.
     
    The test program of the I-221 was cut very short. On the eighth flight of the aircraft, in February 1944, the pilot bailed out at altitude, after seeing flames coming from the turbocharger and smoke in the cockpit. The pilot survived unharmed, but obviously the I-221 was completely destroyed.
     
    I-222/MiG-7
     
     

    Side view of I-222. via ruslet.webnode.cz
     
    The I-222 was a continued development of the I-221. Not only did it have several additional performance improvements, but it was the closest of MiG's high altitude fighters to a “production ready” aircraft. The AM-39A engine was replaced with a more powerful AM-39B, with twin turbo-superchargers, plus a new four-bladed propeller. An improved intercooler was also installed (clearly visible under the central fuselage). To improve the I-222's potential utility as a combat aircraft, 64mm of armored glass was installed in the windscreen, and the cockpit pressure bulkheads were reinforced with armor plate. The fuselage contours were also modified to give the pilot better rearward visibility. Armament was two B-20 cannons, replacing the ShVAKs.
     
    The I-222 made its first flight in May 1944. Relatively little testing was done before the aircraft went to the TSAGI wind tunnel for further refinement. It emerged in September and underwent further testing. Test flights proved that the I-222 had truly exceptional performance. A speed of 691 km/hr was reached, quite respectable for a piston-powered aircraft. The truly astonishing performance figure was the ceiling of 14500 meters, well in excess of any German aircraft (save for the rare and latecoming Ta-152H).
     
    Though the I-222 could likely have been put into production, Soviet authorities assessed (correctly) that by late 1944 there was little threat from high-altitude German aircraft. Nuisance flights by Ju-86s were of little consequence, and German bomber programs such as the He-274 universally failed to bear fruit. Testing of the I-222 continued through late 1945, when the program was cancelled.
     
     
    I-224/Mig-7
     

    As can be seen the I-224 is similar to the I-222. From OKB MiG by Butowski and Miller
     
    The I-224 was a development of the I-222 with an improved AM-39FB engine. Several other minor improvements, such as an improved propeller and modified cooling system. The new aircraft first flew in September 1944. After five flights, it was heavily damaged in an emergency landing. Difficulties continued after the aircraft was repaired in December; the engine had to be replaced in February due to the presence of metal particles in the oil.
     
    Like the I-222, the I-224 demonstrated very good performance at altitude, also climbing to over 14000 meters and recording speeds over 690 km/hr. But by now, it was October 1945, and the war was over. It was decided to fit the I-224 with a fuel-injected AM-44 engine. This was not completed until July of 1946, and by then the time of the piston-engine fighter had passed. Both the I-222 and I-224 programs were shut down in November.
     
    I-225/MiG-11
     

    From OKB MiG by Butowski & Miller
     
    The I-225 was born from the second I-220 prototype. Although the I-225 was still designed for operation at high-altitude, it was decided not to optimize the aircraft for such extreme heights as the I-222 and I-224. It was hoped that this would allow for a higher top speed and heavier armament, among other improvements.
     
    A turbocharged variant of the AM-42 engine (similar to that used on the Il-10 ground attack aircraft) was fitted, providing 2200 horsepower at takeoff. The pressurized cabin was deleted to save weight, and allow the cockpit to be optimized for better visibility. Armament was the same as the I-220; four ShVAK cannons. Armor was added to the windscreen, as well as the pilot's headrest. Improved instrumentation and a new radio system was also added.
     
    As predicted, the I-225 had exceptional performance. The aircraft was capable of speeds in excess of 720 km/hr, and demonstrated good handling characteristics. Unfortunately, the first I-225 prototype was lost after only 15 flights, due to an engine fire.
     
    A second prototype was completed with an AM-42FB engine, and first flew in March 1945. This second prototype was fitted with four B-20 cannons instead of ShVAKs, This prototype was also reported to be capable of over 720 km/hr, as well as able to climb to 5000 meters in under 4 minutes. However, due to continued vibrations, the AM-42 was replaced with an AM-44 in January 1946. This did not solve the issues though, and the I-225, like its predecessors, was not selected for production. All work on the I-225 was shut down in March 1947.
     
     
     
    Remarks
     
    While none of the advanced MiG-3 variants entered production, they did provide the Mikoyan-Gurevich bureau with valuable engineering and design experience. In a different world, one might imagine that some of their designs could have found a niche. The I-210/1 and I-230/1 would have little reason to be built in a world where Yakovlev and Lavochkin fighters exist in the way they did. However, if Germany or another enemy had a developed strategic bombing arm, then the I-220 series fighters could have found a use. Either way, by 1945, it was clear that jet aircraft were the future. Even the Soviets, who had a relatively late start on jet engines, quickly developed aircraft like the MiG-9 and Yak-15 whose performance exceeded any of the MiG-3 variants.
     
     
     
    Sources:
     
    OKB MiG, a History of the Design Bureau and its Aircraft, by Piotr Butowski and Jay Miller
     
    http://www.airvectors.net/avmig3.html
     
    http://www.aviastar.org/air/russia/a_mikoyan-gurevich.php
     
    https://ruslet.webnode.cz/technika/ruska-technika/letecka-technika/a-i-mikojan-a-m-i-gurjevic/ 
    (I-230, I-210, I-211, I-220, I-221, I-222, I-224, and I-225 pages)
     
    http://www.airwar.ru/fighterww2.html
    (I-230, I-231, I-210, I-211, I-220, I-221, I-222, I-224, and I-225 pages)
     
    http://soviethammer.blogspot.com/2015/02/mig-fighter-aircraft-development-wwii.html
  19. Tank You
    LostCosmonaut got a reaction from Domus Acipenseris in J2M Raiden   
    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;
     
    (Airspeed*(Thrust-Drag))/Weight
     
     
     
    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.
     
     

     
     
    Sources:
     
     
    https://www.docdroid.net/gDMQra3/raiden-aeroplane-february-2016.pdf#page=2
    F6F-5 vs. J2M3 Comparison
    http://www.combinedfleet.com/ijna/j2m.htm
    http://www.wwiiaircraftperformance.org/japan/Jack-11-105A.pdf
    https://babel.hathitrust.org/cgi/pt?id=mdp.39015080324281;view=1up;seq=80
    https://archive.org/stream/corporationrepor34unit#page/n15/mode/2up
    http://users.telenet.be/Emmanuel.Gustin/fgun/fgun-pe.html
    http://ww2data.blogspot.com/2016/04/imperial-japanese-navy-explosives-bombs.html
    https://www.pacificwrecks.com/aircraft/j2m/3008.html
    https://www.pacificwrecks.com/aircraft/j2m/3013.html
    https://www.pacificwrecks.com/aircraft/j2m/3014.html
     
     
    Further reading:
     
    An additional two dozen Raiden photos: https://www.worldwarphotos.info/gallery/japan/aircrafts/j2m-raiden/
     
     
  20. Tank You
    LostCosmonaut reacted to TokyoMorose in What the Hell is the Point of Interleaved Road Wheels?   
    I know I am late here, but the loon wouldn't happen to be Ernst Kniepkamp would it? I know with the half-tracks and Panzer III he was directly the guy responsible for those elements - and the Tiger I work at Henschel was also his pet project of the time.
     
    And wait, I have Forcyk's book.... and yep it is Kneipkamp. Head of all tank projects at the Wehrmacht, and had been the chief army engineer even before the Nazi takeover when it was the "Military Automotive Department". Even the tiny Kettenkrad has the interleaved wheels, and yep the patent on that is "E. Kneipkamp".
  21. Tank You
    LostCosmonaut reacted to Beer in Czechoslovak interwar bits   
    A bit about the God of War. With Czechoslovak artillery it was exactly opposite than with the airforce. The artillery was very strong and had many very potent weapons, nearly all of them were local design and production. The guns were also widely exported. The field army had some 80 artillery regiments with over 2200 pieces (not counting any fortification guns or auxilliary units). As with most of other weapons large part of them (plus huge ammo stocks - and actually also hundreds of thousands Sudeten Deutsche soldaten) sadly presented a massive gift for the Wehrmacht. A bitter aftermath of Münich. 
     
    10 cm Light howitzer vz.14/19 (towed by horses). Very well known weapon used by nearly everyone in the central Europe and during WW2 by Wehrmacht and Italy. In 1938 Czechoslovakia had around 600 pieces. Wehrmacht got 400+, Slovakia 180+. Together with Polish and Austrian ones Wehrmacht later had around 1000 pieces. 

     
    10 cm light howitzer vz.30 (for motorized units and so called fast divisions). Very modern weapon for its time based on export Yugoslav model but widely modified for domestic use (not always in the better way due to various compromises such as necessity to allow use of older ammo for vz.14/19). 160+ guns were available in 1938. It was later successfully used by Wehrmacht and Slovakia. The only preserved piece is in USA.  

     
    10 cm light howitzer vz.38 (for mechanized units). This modern weapon was never fielded despite it was addopted but too late - the complete order (260 pieces) was canceled after Münich. As with the previous gun it was again based on successful export models F and H (Yugoslavia, Romania, Iran, Latvia, Afghanistan). Germany took 84 guns made for Latvia and sold 57 to Romania and 27 to Finland. Those 27 Finnish guns officially fired 75 thousand rounds during the war and served successfully till 1970'. The prototype of the Czechoslovak version (H3) is on display in Lešany museum near Prague together with one Finnish piece (a place sure worth visiting). 

     
    15 cm heavy howitzer vz.15 (usually towed by heavy tractors). This gun was already rather obsolete by 1938 but 40+ pieces were still used. The guns were taken over by Wehrmacht and used on the western front and a half was later sold to Finland. It's on display in Lešany. 
     
     
    15 cm heavy howitzer vz.14/16 (for horse traction). Well known weapon of the WW1. Czechoslovakia used some 180 pieces built after WW1 and they were used till Münich. Hundreds of these guns were used by Italy, others by Austria, Romania, Greece etc. Wehrmacht took around 100 pieces and used most of them in Austrian units which were used to the same weapon. The gun is preserved in Lešany. 

     
    15 cm heavy howitzer vz.25 (for horse traction). Czechoslovak army had 340 pieces of this rather light and potent weapon (still pretty good by late 30'). Werhmacht and Slovakia successfully used them till the end of war. You can see this gun in Lešany as well. 

     
    155 mm heavy howitzer vz.15/17. This well known French gun was a stop-gap solution in 1919 when the army badly needed whatever it could get to fight the so-called Hungarian Soviet Republic (which was defeated by Romanian and Czechoslovak forces and ceased to exist the same year). Czechoslovakia had 50 pieces but all of them were retired by 1937. Maybe Wehrmacht got them from some storage but there is no record about that. Anyway it used plenty of these guns from French and Polish stocks. 

     
    15 cm heavy howitzer vz.37. This weapon was arguably the best of its class by late 30' but as with many other weapons of Czechoslovak production it was largely exported (series K) but not used by the Czechoslovak army itself. When the army decided to addopt this weapon used already by Turkey, Romania or Yugoslavia it was hesitating that long about its modifications (for example whether it prefers a variant for motorized or horse traction) that the first guns were delivered only after Münich. Wehrmacht took a whole batch of 110+ pieces and used them till the end of war. Some sources say that Germany originally signed an order for another production but a lobby from German companies led to its cancelation. The Czechoslovak variant of the gun is on display in Lešany museum.  

     
    10 cm mountain howitzer vz.16/19. This weapon was successfully used during the WW1 and extensively modernized by Czechoslovakia in 1920'. It was being transported disassembled into three pieces and with the overall weight 1350 kg it could fire to nearly 10 km distance (the modernized version). It was widely used by Italy, Austria (later Wehrmacht) and in small numbers also by Slovakia and Greece. Czechoslovakia had 66 pieces of which 44 were modernized and dislocated mostly in the mountains of Slovakia. This gun is on display in Lešany. 

     
    That's it for howitzers. I have omitted many prorotypes, some of which are on display in Lešany as well. Let's continue later with field guns. 
  22. Tank You
    LostCosmonaut reacted to N-L-M in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    I did read the document, and your conclusions from it are so off-base that I'm not sure you read it.
    Consider, for example, the closing remarks, on page III of the document (page 6 of the PDF):

    "small real cost growth" is not at all the situation you describe.

    A growth of 19%, mostly because extra features were added in? say it ain't so!


    And again, 19% growth for features, mainly the strengthened powertrain, is literal taxpayer rape. wew.
    Also, the 507k is hardware costs for a single vehicle. Doubling the order for what is pretty much the same hardware cost per unit does not mean that the hardware cost per unit has doubled, and indeed the paper only talks about an estimated price increase if 19%. I really don't know how you could even reach that interpretation.
    You know, that's a fascinating source, but once again your source does not say what you claim it does.
    To wit, the Army's response to that claim:

    Page 89 of the very PDF you posted. If you're gonna cherry pick quotes from sources, at least bother to read your entire source. Cause it firmly disagrees with the conclusion you are trying to draw from it.

    Fun for the whole family!
    And a bit more, just to get the point across:


    Oh no muh poor taxpayer getting ripped off for squillions of dollars oh no
    It's almost as if getting sent to an active war zone in the sandbox leads to greater wear and therefore need for spare parts, as well as high fuel consumption, while the M60A3s are left at home or in Europe, who'd a-thunk it?
    The cost of the M1 exceeding the M1A1 is interesting, wonder what led to that.
    You do have a legit point that in practice it appears that the M1 has turned out to be expensive to operate, but that's a far cry from it being a case of the US MIC "raping the taxpayer".

    1-800-come-on-now
    Ah, a clear sign that you indeed don't know what you're talking about, thanks for playing.
    for reference, the 1.5 trillion is a lifecycle cost for the entire fucking fleet. Not a sunk cost. And that's a really shitty way to dodge the point, which was that early LRIP costs are not indicative of full scale production.
    All the congressional testimony you've posted says otherwise, the design to cost was largely successful and the tank was delivered on time and mostly on budget, a great achievement for any development program, let alone one run by the US Army.
    It was absolutely the successor program to the failed MBT-70, what are you on to?
    So the US Army disagrees with you on the cost issue, and by all accounts the Abrams program has been a resounding success. You don't scale up a 3300 tank buy to 7000 if the cost balloons out of control, and sufficient evidence has been posted in this thread (ironically, by you) to disprove that notion.
    Inflation is a hell of a drug, and the extras in the TTS don't help.
     
    But anyway, TL;DR there's plenty of evidence that the Design-To-Cost of the M1 Abrams was by and large successful, and that it was successfully limited to a unit hardware cost significantly below that of the MBT-70, thus backing up the claim that started this whole discussion, ie that the Abrams was a budget tank born from the failure of the MBT-70 project.
    Not really no. What is however ironic is that you're calling out Ram despite you being the one who's incredibly wrong about this. The F-35 cost issue is prime bait and you took it like a champ. Thanks for playing.
  23. Tank You
    LostCosmonaut reacted to Clan_Ghost_Bear in Space Documents Thread   
    A collection of docs overviewing some plans for the US army moonbase, including what weapons they were going to use for defense.
    https://apps.dtic.mil/dtic/tr/fulltext/u2/a047426.pdf
  24. Tank You
    LostCosmonaut reacted to skylancer-3441 in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    article on AUSA 1975 exhibition, published in International Defense Review 1975-06

     
    article on AUSA 1976 exhibition, published in International Defense Review 1977-01

     
    article on AUSA 1977 exhibition, published in International Defense Review 1978-01

     
  25. Tank You
    LostCosmonaut reacted to Beer in Czechoslovak interwar bits   
    Let's move from the fortification system to the something a lot less bright... the airforce. The airforce was quite clearly the weakest point of the Czechoslovak army mostly due to the too conservative approach of the MOD. Nevertheless some interesting designs saw the daylight. Here are couple of those not very well known... 
     
    Aero A-102. This plane was originally a bi-plane similar to Polikarpov i-15 (top wings connected directly with the fuselage) and one of the competitors to the Avia B-34. It was never built and lost the bid already in paper phase. Nevertheless Aero redesigned the plane to a braced low-wing. It was year 1934 and the MOD was rather conservative and refused such design. A new itteration came in summer 1934 with a shoulder wing configuration similar to Polish PZL P.11 but more aerodynamically clean, better armed and with much stronger engine. Despite the plane had weaker engine than Avia B-534, it was much faster simply because it was no bi-plane. The top speed with locally produced 800 Hp Gnome Rhone Mistral Major 14 Kfs engine was 430 km/h (B-534 had locally produced 860 Hp Hispano Suiza 12Ybrs but the license owner Avia, part of Škoda company, was doing everything it could to prevent other companies to use it). The armament was made of four 7,92 mm MGs vz.30 in the wings and optionally with light bombs. The plane actually flew and went through extensive testing and showed very good haracteristics However in the end it was rejected due to too high landing speed because it had no flaps (140 km/h). That was a real pity because otherwise it was clearly superior design to bi-plane Avia B-534. 
     

     
    Avia B-35. OK, not that unknown but neverthless interesting. Czechoslovakia found late that the speed will be crucial in the future air battles. It tried to obtain Hurricanes from GB but the negotiations were not successful. The prototyp of the modern B-35 first flew on 28th September 1938 which is basically all you need to know about the future fate of it. Aside of that the plane was up to date. It had an eliptic wing made of wooden structure with an "armoured plywood" panels (plywood with 0,2 mm aluminium layer). The fuselage was made of steel tubes covered by magnesium-aluminium alloy panels. The engine was supposed to be 1000 Hp Hispano Suiza 12Y-1000C, three-blade adjustable propeller, retractable gear and flaps. The armament was made of one 20 mm Hispano 404 canon and two 7,92 mm MGs vz.30. The theoretical top speed was around 570 km/h. However the first prototype had fixed gear, two-blade wooden propeler and 860 Hp 12Ydrs engine. Despite it had the same engine as the B-534 and not yet the retractable gear it was roughly 100 km/h faster than the B-534 (485 km/h was achieved already in the very first flights). After the occupation the development went pretty slow and in the end 12 B-135 planes were delivered to Bulgaria in 1942 when they were already obsolete. B-135 had the retractable gear but it still had the old 860 Hp engine and the wooden two blade propeler (it achieved 550 km/h with it), moreover the canon was never installed in them. Despite that there are records that on 30th March 1944 one B-135 shot down a Liberator during an atack on Ploesti. 

     
    Aero A-300. The funy thing about Czechoslovak air force is that in the fall of 1938 it was about to go in the war with Germany with its fastest planes being bombers. The airforce had roughly 60 fast Soviet Tupolev SB-2 bombers eqiped with Czech-made Hispano engines) and a licence production was just starting in the Avia factory with a name Avia B-71. Except that the rest of the bomber air force isn't worth talking about as it was hopelessly obsolete. The MOD knew that and tried to obtain a locally produced modern plane heavier than the Tupolev. The Aero A-300 first flew in spring 1938 but the testing was not finished until after Münich when it was officially adopted without the production ever started. It was a very fast (450-460 km/h) low-wing twin engine bomber with a capacity of up to 1000 kg of bombs. The crew of four had three 7,92 mm MGs (retractable dorsal,  and belly posts plus one in the glass front). The engines were 830 Hp Bristol Mercury IX with De Havilland-Hamilton adjustable three-blade propellers. The fuselage was made of steel tubes with aluminium and textile cover. The wings were wooden and the plane had retractable gear and flaps. 
     
     
     
    Letov Š-50. A recon and light bomber plane (with tasks similar to FW-189). Due to some issues in the development it first flew only in September 1938 and shortly after that the development was stopped. The plane had again tubular fuselage structure with aluminium cover but this time even thew wings were of steel tubular design. The engines were 420 Hp Avia Rk-17 equipped with two blade adjustable Hamilton propellers. The gear was fixed. The crew of three had three 7,92 mm vz.30 MGs (one in the Armstrong Withworth turret, one in the belly firing post and one forward firing in the wing). The plane could carry various photocameras, radio station and up to 600 kg of bombs. 

     
    Aero A-304. This plane was originally a passenger plane ordered by Czechoslovak Airlines but they didn't want to wait and bought Airspeed Envoy isntead. The airforce liked the plane and let it be modified to a recon/light bomber plane. Nineteen were ordered and few of them were probably delivered before Münich (only one confirmed). Luftwaffe used them later as training planes. The fuselage was made of steel tubes covered by plywood and textile. The wings were wooden with plywood cover. The engines 430 Hp Walter Super Castor worked with wooden two blade propellers and the plane could reach 325 km/h with them. The gear was retractable. The crew had three 7,92 mm vz.30 MGs (one in the dorsal turret, one in the belly and one in the frontal post). It could carry 300 kg of bombs. 

     
    One curiosity at the end. Have you known that interwar Czechoslovakia was using special fuel to decrease the dependence on oil import? It used a fuel called Bi-Bo-Li which had two variants - aviation and vehicle one. The aviation one was made of 44% ethanol, 44% benzene and 12% of kerossene. The vehicle one was made of 50% ethanol, 30% benzene and 20% petrol. The Czechoslovak army and the airforce collected rather large fuel and ammo supplies, in fact reasonably larger than Wehrmacht and Luftwaffe had in late 1938 (not in overall volume but in the time it could use them). 
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