Jump to content


  • Content Count

  • Joined

  • Last visited

  • Days Won


About renhanxue

  • Rank

Personal Information

  • Location
    Stockholm, Sweden

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. That's scans of the official air force magazine (the title literally translates to "Air Force News"). It was published 4-5 times a year between 1960 and 2003. There's a number of interesting articles in there but as an offical propaganda outlet it's not always the most useful source, and it's usually pretty thin on the sort of interesting details nerds love to see. Also, that page only has some articles scanned. Here are scans of every issue 1960-2003: https://www.aef.se/Flygvapnet/Tidskrifter/FV_Nytt/FVN_oversikt.htm
  2. There is a thread about turning the AJS 37 into an AJ 37 here:
  3. Given the way the SFI describes it, it must absolutely move within each zone. Elgon does not translate to just "electrical", it's a very specific technical term (now long out of use, though) that translates to "synchro", and specifically I think it refers to a synchro-transmitter. That's effectively a very simple analog angle sensor, and given that it's explicitly mentioned that the sensor is mechanically attached to the nozzle via a pulley, I'm quite certain this is a very analog instrument that just reads the rotation of the pulley directly and rotates the indicator needle to match. There's
  4. I don't understand what you're trying to say. For a clean aircraft, yes, the diagram ends at VNE before thrust=drag is reached, so we don't know exactly what the thrust-limited top speed actually is, or even if there is another limit other than available thrust (I don't think there is, but as you say, we don't know that). For an aircraft with payload, this is not the case - there is a known top speed (where drag > thrust) and it's below VNE, and we can see this from the diagrams. Hence when Rossmum said that he's seen aircraft doing 1600km/h IAS at sea level with external payload, I respond
  5. What? I just posted a thrust-drag diagram that clearly shows even the JA37 not having enough thrust to reach its VNE at sea level with the lightest loadouts listed. Just follow the line marked 1 in the diagram and you'll reach T=D well below M 1.2. Or just extrapolate where the line marked 0 (clean aircraft) is going and it's pretty obvious that you'll run out of thrust just above M 1.2/1450 km/h IAS even then. I can easily see 1500 km/h being possible with a clean aircraft and you can probably do a bit better than that on a cold day even. With any payload at all though you're gonna get limite
  6. Yeah, doing 1600km/h on the deck with external payload seems extremely unrealistic to me, there's no way I can see it having enough thrust to do that. Clean maybe, it's at least conceivable, but with payload? Can't see it happening.
  7. Not by very much. The JA37 only has maybe 5 kN more thrust at M 1.1 at sea level. Thust-drag diagrams below. The main advantage of the RM8B is that it deals better with high alpha and is less susceptible to compressor stalls in general. AJ 37: JA 37: See this thread for most of the original Swedish flight manuals, where these performance charts are taken from.
  8. Triple posting, sorry about that, but it's relevant. In the book System 37 Viggen, Kenneth Nilsson (longtime Saab employee, head of the applied aerodynamics department 1992-2001) relates the following story regarding work he did at Saab in the early 1970's studying the feasibility of beating a few FAI records with the Viggen, in the hopes that it would help it on the export market. My translation. edit: to be clear, I think going much beyond Mach 1.2 at sea level in an AJ37 is probably unrealistic, but I have never seen anything that indicates that engine, intakes or airframe in genera
  9. The F-111 is from the same time period as the Viggen and is limited to Mach 1.2 at sea level for the same reason hilmerby mentions (skin temperature). The F-111 has equipment for warning about skin overheating, though, and the Viggen does not. There is nothing magical about neither of these aircraft, nor their engines.
  10. There is no such part of the manual to my knowledge. It just lists VNE as 1350km/h IAS on the AJ37, 1450km/h IAS on the JA37. The JA37 has a slightly different engine with an extra compressor stage that makes it more resistant to compressor stalls and it has a few percent more power, but is otherwise extremely similar to the AJ37 in most ways relevant to this issue. I believe that the aerodynamics compendium discusses some issues with available pitch authority/load factor at very high dynamic pressures because of limitations with the amount of force the hydraulics can exert on the elevons, but
  11. Yes, exactly. In level flight the aircraft isn't actually level with respect to the horizon, it's always somewhat nose-up, and so the radar beam points slightly up as well. I don't know why they did it like this on the real aircraft because it seems it removes some margin of error that you would otherwise have, but as far as I understand the SFI that's how it works.
  12. On the real aircraft, switching to TA mode sets the "neutral" antenna elevation (that is, the elevation that you get if the elevation knob is centered, in its middle snap position) to 0° relative to the aircraft X-axis, but since you have some positive alpha in level flight, your attitude is somewhat nose-up, so that ends up showing obstacles slightly above your actual flight altitude. In normal A1/A2 modes the neutral antenna elevation is actually slightly negative relative to the aircraft X-axis, between -0.5° and -3° depending on range setting and whether the altitude is above 600 meters or
  13. In reality, you would not be able to use the navigational computer at all in most of the areas on the maps currently available or announced for DCS (the exceptions being the western half of Caucasus and the small part of Normandy that lies east of Greenwich). The reason for this is that on the real nav computer, you can enter the longitude and latitude in any order, and it'll autodetect which is which. It can do this because it comes programmed with the restriction that longitude must be greater than 0° but smaller than 40°, while latitude must be greater than 40° but smaller than 90°. If you'
  • Create New...