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renhanxue

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Everything posted by renhanxue

  1. renhanxue
    the strv 103 is faster to lay against a stationary target from the short halt than the M60A1 AOS eat shit, stabilization havers
  2. renhanxue
    Also, FWIW, the Swedish army textbook "Electronic warfare handbook for the air defense forces: radar and radar technology" from 2004 (an excellent book, it's a pity I don't have time to translate it) briefly discusses stealth/signature reduction and says there are three practical ways to reduce radar returns, namely: 1) shaping (the single most important method) 2) using radar absorbent materials (several techniques are discussed) 3) active interference (the active cancellation thing we're talking about here) but that only the first two are operational "today" (so in 2004). So they seem to have viewed it as thing that was not yet practically achievable in 2004 but one that was likely to become so in the near future. I really do wonder if there's a newer edition of this book somewhere...
  3. renhanxue
    I'm pretty damn sure that if you have an AESA yourself your own radar antenna is a significant part of your RWR. Even back in the early 70's radars had passive modes that let you see and record whatever jamming was coming at you (I know for a fact that the AJ 37 had this when it entered service in '71 and I'd be really surprised if everyone else didn't have it too). Today, it'd be really silly to have all this emissions control and then not use your best antenna for listening. It's not like shuffling signals around between different systems is a hard problem these days. As far as active cancellation goes, I can only reiterate that the dude claims that they could do wide spectrum radio cancellation. Granted, in a lab, but still.
  4. renhanxue
    The receiver has access to the same technology as the transmitter these days, you know. RWR's aren't the kind of 60's thing that simply turns the received radar sweep into an audible sine wave so you can hear it go beep in your headset anymore. Sure, you'll fool older systems but if the other guy has the same level of technology you're back to the radar equation and the defending side always has the advantage of their energy being inversely proportional to R² rather than R⁴. If the transmitting radar can detect the bouncing signal the illuminated aircraft sure as heck can. Also related, someone on SA posted this thing in response to a post about ~aerospace technology~ in acoustic noise cancelling headphones: I'm pretty sure I recall Saab mentioning something like this in connection to the Gripen E, and I think that stuff (well all the EW computer thingies in general) is one of the reason for the new cooling air intake on the base of the tailfin. It wouldn't surprise me if that kind of technology is on all the 4.5th generation fighters within the next ten years or so. edit: then one of the guys who work with future warfare stuff posted this in a different discussion:
  5. renhanxue
    AJ and AJS 37 Viggen flight manuals, including almost all the formerly classified parts. Only available in Swedish, because the Viggen never got exported anywhere.
  6. renhanxue
    RU. I've mainly been in contact with Yuri Pasholok and Anton-whatshisname (cannoneer). I have no contact whatsoever with WG EU.
  7. renhanxue
    It is a 7,5 cm gun. Strv m/42-57 (tank model 1942, modernized version of 1957) was the internal working name for what would become the strv 74. They needed a new turret to fit a long 7,5 cm gun instead of the stubby peashooter the m/42 had, so four options were investigated: A.1 was a conventional turret (this option was chosen for the historical strv 74) A.2 was an oscillating turret, AMX 13 style A.3 was trying to make an earlier turret design actually work (the "split turret") B was abandoning the re-turreting idea and rebuilding the chassis to a casemate TD. So this option was actually kinda-sorta considered for a short time in the early 1950's. It's unclear if they actually intended to just buy or license produce AMX 13 turrets though; personally I believe the intention was to design and produce a domestic turret. Whatever, this is good enough for WoT. When the m/42 was being developed they did consider a long-ish 57 mm gun for it but it was considered insignificantly better at armor penetration than the short 7,5 cm. I'm doing research for the Swedish tree on Wargaming's behalf (as a consultant) and while I'm under an NDA, I'll try to answer any questions you might have re: the rationale behind making the choices we did.
  8. renhanxue
    I only have one report to go off (in a test rig, not on an actual tank, with the plastic jerry can between 35 and 80 cm from the armor plate) but the results with three different types of 60's vintage HEAT rounds are as follows. Max measurable penetration in this test is 310 mm. If the can is empty: no measurable effect. Different rounds behave differently depending on fuze type, though: rounds from pskott m/68 (disposable launcher, expected penetration ~310mm RHA) and pvpj 1110 (9 cm recoilless rifle, expected penetration 325mm RHA) detonate when hitting the can, rounds from Carl Gustav (8,4cm recoilless rifle, shape-stabilized round with long probe fuze, expected penetration 350mm RHA) go through the can and detonate only when hitting the armor plate in three cases out of four. If the can is filled with water: fucks with the fuzing on the Carl Gustav rounds, two out of three rounds fired failed to detonate and the third did something weird (the results table says "chock ignition, point of impact warm" with no further explanation) resulting in no measured penetration. The pskott m/68 and pvpj 1110 rounds detonate normally when hitting the can but penetration is reduced roughly 25-50% from the expected values - there is a lot of variation though, especially in the pvpj 1110 case. These rounds all have a listed penetration in the 300-350mm RHA range though so even reducing it by 50% isn't nearly enough to prevent a penetration of the actual side armor.
  9. renhanxue
    Basic planning document dated May 4th 1945, telling the commander of the 3rd army corps to get crackin' on that planning. The invasion force is roughly one and a half infantry divisions, an independent armored brigade, an independent motorized brigade, a bunch of independent artillery batteries and a whole lot of AA including one train-mounted AA company. Additionally the invasion is to be supported by "most of the air force", the ancient coastal defense ships HMS Tapperheten (1901) and Oscar II (1905), three destroyer divisions, a whole bunch of torpedo boats, minesweepers and other smaller craft, nine 21 cm mobile coastal artillery guns, a whole bunch of 15 cm mobile coastal artillery guns and all of the fixed coastal artillery in the Sound. Also, the Danish exile "police brigade" (Danish army personnel with Swedish weapons). If your landing crafts look like this, though, you're gonna have a bad time:
  10. renhanxue
    "Heavy metal Centurion" with chain standoff screens. August 1976.
  11. renhanxue
    To be honest your guess is as good as mine, the "not too reliable" part is a pretty literal translation of the original Swedish. Personally I'm inclined to think you're right though, it simply wasn't all that good at detecting aircraft. But it could also be a little from column A, a little from column B. The JA 37 didn't get a similar unit, after all.
  12. renhanxue
    And so are all the Eurocanard ones. If you want to say that the current Russian ones are worse, sure, I'll buy that, but it doesn't really have anything to with the state of the Draken's IRST in the 60's or the MiG-29's in the 90's. Speaking of the men of honor and silence who rushed along between the treetops of pine and fir, though, I recently saw a former Lansen and AJ 37 pilot relate this anecdote and I figured I might as well stick it here: The Swedish cold war era air force did not believe in loitering.
  13. renhanxue
    Really? The IRST on the Draken was early 1960's analog technology. Making arguments about today's IRST based on that is, uh, a bit of a stretch. I think the actual problem there was that while we were waiting for the 9L to materialize we had to make do with the old 9P, which was hardly impressive in 1980. We didn't get the 9L until the late 80's and by then the 9M was everywhere and I think people were jealous.
  14. renhanxue
    Continued:
  15. renhanxue
    I've posted this on SomethingAwful before, but here's a repost for those of you who haven't given Lowtax tenbux. Warning: it's very long. The Swedish original is called JA 37: pilot och system and is a transcript of a witness seminar held at the Stockholm Museum of Technology in 2007, with a lot of old geezers who had worked on the development of both the Viggen and other Saab aircraft. A very brief glossary: - FMV is the Defense Materiel Administration, which was (and is) the government authority responsible for buying and developing all kinds of equipment for the Swedish armed forces. At the time when the Viggen was being developed, FMV still had a lot of engineers in house, which was considered important since it was thought at that time that in order to buy or develop a good system you had to know how it worked. - SRA is Svenska Radioaktiebolaget (Swedish Radio Company). Acquired by Ericsson in 1983. - LM Ericsson is just Ericsson. The name comes from the full formal name of the company, "Telefonaktiebolaget L M Ericsson", which in turn is named after its founder Lars Magnus Ericsson. - JA 37 is the fighter version of the Viggen. - AJ 37 is the strike version, which predates the fighter version by about ten years (entered service around 1970; the JA 37 around 1980). - 35, or aircraft 35 is the Draken. - 37, or aircraft 37 is the Viggen airframe in general. - 39, or aircraft 39, or JAS 39 is the Gripen. My comments are in parentheses. Please ask away if there's anything that seems unclear.
  16. renhanxue
    Yep, I have a shitton of graphs. I got drag coeffs for various loadouts, I got fuel expended per minute or per km in a whole bunch of different scenarios, I got range graphs, I got acceleration graphs, I got climb graphs, I got descent graphs, I'm basically drowning in graphs. Problem is figuring out what to use them for.
  17. renhanxue
    You see this number quoted so much and yet it means so little without a lot more details. If you've got drop tanks, do you get rid of them when you're empty? Do you even drop your payload when you reach your halfway point? How much fuel do you reserve for maneuvering/as a safety margin? Does the scenario include loitering, and if so for how long? Does "high altitude" mean most economical cruise altitude? In the flight manual for the Viggen I've got nice graphs for max range with a few different loadouts, but they all assume you're carrying everything all the way. I want to calculate some decently comparable numbers, so help a fellow nerd out?
  18. renhanxue
    Some Viggen flight manuals in Swedish: AJS 37 Viggen, part 1 (unclassified part) AJ 37 Viggen, part 2 chapter 1 (formerly classified secret) AJ 37 Viggen, part 3 (formerly classified secret; contains performance charts) Let me know if you want some bits and pieces translated.
  19. renhanxue
    I was like "surely he must be joking"
  20. renhanxue
    Strap twenty 10,5 cm recoilless rifles to the back of a truck in 1944, what do you get? Rocket artillery, without the rockets! Of course, to try to fool spies they called it "spare gun barrel carrier, provisional model 1943" (reserveldrörsvagn fm/43, a vehicle so obscure it is literally ungoogleable, at least until now). Later entered service as 10,5 cm salvkanon m/46, but AFAIK only four vehicles were ever manufactured.
  21. renhanxue
    Dunno where to put this really but here you go: A proposal to Hägglund & Söner AB for a Weapon Control System and Ballistic Computer for the Swedish Ikv, from Honeywell's Ordnance Division, dated March 24, 1967.
  22. renhanxue
    Fpl AJS 37 speciell förarinstruktion The unclassified part of the AJS 37 Viggen flight manual. edit: original link was missing half the pages, fixed now
  23. renhanxue
    Viggens in the field (kinda literally in that first one). First one's most likely from the 70's, second from some big field maneuver in the late 80's IIRC.
  24. renhanxue
    Part 1 - general info, checklists, etc. Similar to the unclassified Sk 35C flight manual in English that's listed in the document thread, but contains more stuff (such as weapons procedures etc). Part 2 - by far the most interesting part. Describes the airplane as a system and the working principles of its most important subsystems (radar, data link receiver, sights, armament etc) as well as its tactical use. Tons of cool diagrams in here. Part 3 - performance charts for every imaginable situation and load alternative Part 4 - more of the same Climbing to 11000 meters eats about 25% of the internal fuel, by the way. It's a very intercepty interceptor. For you poor unfortunate souls who don't read Swedish, I might be back later with more interesting tidbits.
  25. renhanxue
    The national archives emailed. About six months after I requested, they've finally declassified the secret parts of the J 35D and J 35F flight manuals. I know what I'm doing this afternoon.
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