renhanxue

Are you sure about that? They are on DC power, yes, but on a secondary bus, so having no generator or ground power should turn them off. I think... The cockpit interior lightning (kabinbelysning) is on the main battery bus before the main power switch though so those are usable without any power at all.

Viggen, gentlemen. It does what it needs to, just usually not in the way you expect it.

Not really? There's only one high altitude acceleration diagram in the SFI and it's with a mixed air-to-air loadout (drop tank, two gun pods, one rb 05 and one rb 24), and with that it's supposed to take about four and a half minutes to go from Mach 0.9 to Mach 1.5 at max zone 3.

You guys are doing seriously awesome work here. I'm as impressed by that as by the fact that the simulation is so accurate and detailed down to these subsystems in the engine and fuel feed system that you can actually do these tests in a meaningful way. You know the simulation is good when the real flight manual works better as documentation for the game than the game's manual does.

40 years, not 20, and that's actually the lowest possible time limit - it gets worse with certain types of information (military intelligence is up to 90 years now after the law changed... last year, I think? used to be 70 years). 15 kap 2 § Offentlighets- och sekretesslagen (2009:400): Emphasis mine. I would suggest you read Krigsarkivet's memo Att forska i hemliga arkiv for a quick primer on how this actually works. I reiterate that as far as I know, no part of the JA 37 flight manual other than part 4 has been declassified. It almost certainly could be declassified if you requested it, but until it is reviewed and approved for release it doesn't matter if the time limit has expired or not (it hasn't, though) - it's still classified. If the time limit has expired they must declassify it when you ask for it (barring cabinet-level intervention), but they still have to review it, and the status does not change until you actually request it. It doesn't get declassified automatically. If the time limit hasn't expired they can declassify but the review process takes a lot longer and it's generally a pain. If you know something I don't, though, I would be very interested in hearing it, but as far as the usual way of getting access to these things goes (that is, going via the national archives), there's nothing to see, and I should know.

Equilibrium airspeed with a clean aircraft is around Mach 0.92 or something like that at 10km. Any external loadout at all (including the drop tank) and you can't maintain level flight at 10km on dry thrust at any airspeed, and forget about climbing there dry. However, with low drag loadouts (basically, anything that doesn't involve the anti-ship missiles, bombs or rocket pods - unsure about the bk 90) you should be able to maintain Mach 0.9 or at the very least 0.85 at altitudes between, say, 4 and 8 km, ish. Best distance economy is achieved with Mach 0.9 at around 7-7.5 km with most loadouts except the draggiest ones (again, rocket pods, bombs, anti-ship missiles). With 16 bombs you need to go down to around 6 km. If you're ferrying a clean aircraft with full fuel though, the manual is correct and 10km is the best cruise altitude.

I can't tell you exactly what is going on, but as far as I understand the SFI, the computer calculates average projectile velocity (for both gun pods and rockets) using the aircraft's velocity vector, altitude relative to the target and a constant specific to the weapon type. Then it calculates projectile travel time to target using that, measured or triangulated slant range to the target, and air temperature (at takeoff, as I understand it). If you know the slant range and the pitch angle you also know the altitude relative to the target though, as previously discussed, so QFE may be irrelevant after all. https://forums.eagle.ru/showthread.php?t=168144 SFI AJS 37 del 3, page 58 and 59 in the PDF.

Ooookay. No idea what you're basing the claims on but if you know something I don't I'd be very interested in hearing about it. I mean, I agree that the JA 37 flight manual is almost certainly not something the authorities considers sensitive today, but that doesn't mean it's actually declassified, nor that it's accessible. If you want it, all you need to do is send the national military archives (Krigsarkivet) a request to see it - a "begäran att få ta del av allmän handling". They are obligated to handle your request and release if possible, but before you get to see it, they need to review the document and approve it for release, regardless of how old it is. A classified document never gets declassified automatically - it must always be reviewed before it can be released. There are legal limits on how long the authorities can deny release for security reasons, but that doesn't mean it's automatically released once those are passed. I know for a fact that as of right now, part 4 of the JA 37 flight manual (which contains performance charts) is the only declassified part - it's listed in the national archives' open library catalog. One of these days I'll PDF-ify it. When I got the AJS 37 flight manual declassified they denied release for the chapter on ECM and RWR, by the way. It's probably not sensitive but they were uncertain and it was apparently a lot of work to get it approved for release so they just gave me the rest and told me to send a new request if I was interested in that chapter, and they'd look into it.

Great minds think alike; I find your drawing to have eerie similarities to this bit of the SFI: As for how the slant range and aim point are actually calculated, please refer to fig. 14 and 15 respectively:

I'm not sure why you're re-stating the obvious...? bones1014 asked about what the radar altimeter was doing and I explained why it's not used for this - it's doesn't provide the data you want, except in special cases (flat ground). I said nothing about the main radar. Either way, if you're missing ground targets while using radar ranging for rockets/gun pods, keep the following things in mind: 1. Is lead calculation active? If it's active it's vital to not unsafe before you have a stable aim point on the target, or any aim point movement will be interpreted as target movement that the computer will attempt to compensate for. TAKT/IN/221000 to disable this, enter with LS/SKU. 2. Are you locking before or after trigger unsafe? If you're going for targets of opportunity you might want to try the latter, TAKT/IN/252000 to select that, again enter with LS/SKU. 3. Air pressure is still taken into account for rocket ballistics calculations (drag/velocity loss) so having it set in the right neighborhood is still important. 4. The ballistic calculations are not CCIP - that is, they are not continuously correct. The aim point is "close to" correct (scientifically accurate term, used in the SFI) at the longest permitted firing range and actually correct when the firing signal in the HUD is given ("wings" on the flight path marker blinking).

Nothing special. Knowing your current altitude isn't interesting, what you want to know is the target's altitude and there's nothing that says it's got any relation to yours.

Usually what happens is that the symbology disappears under the nose of the aircraft. Put the HUD glass in the lower position, fly lower and fly faster and the targeting info should be there.

As per the SFI (flight manual for the real aircraft), the target waypoint should always be at the estimated target position. With standoff weapons you simply switch navigation waypoints manually after weapons release. e: like so - the illustration has both waypoint numbers and master modes marked (U5 is the pop-up point for the target waypoint M5):

The engine is trying to tell you that if you keep doing what you're doing it's gonna ditch you and let you sort this whole "flying" thing out on your own really soon. (what grunf said - don't exceed 18° AoA if you like having thrust)

Well, short takeoff is an actual separate procedure. If you just do a rolling start with full fuel and four rocket pods in zone 2, it's gonna feel like a school bus. It'll get you off the ground, sure, but it's not going to "wow" you, at all. If you want to do an actual short takeoff, first of all you need to a) go from military power to max zone 3 while the brakes are still applied (release brakes as soon as aircraft starts to skid) and b) ignore the HUD's idea of when you're supposed to rotate. Instead you follow this diagram (takeoff weight in tons on the left side of each polygon, air temperature in °C on the right; rotation speed in km/h IAS on the horizontal axis): Minimum permitted rotation speed is 190 km/h IAS. Rotate in time, but do not over-rotate! You must maintain exactly the alpha you need for sufficient lift while not exceeding it so you get too much drag. The HUD tells you roughly the attitude you should maintain; just align the flight path marker with the tops of the outermost "posts" and you'll get 13° above the horizon, which is usually what you want at max zone 3. If you do it right (no tailwind or other weird things going on) you should have a ground roll <700m and reach Mach 0.55 within 45-50 seconds after brakes release (assuming you level out at the lowest safe altitude) on a standard day, even with the heaviest possible loadouts.

My understanding is the same as scaflight's; it does need to know what base you are actually on when taking off, but if that is set properly then it should autodetect runway heading as long as the runway is one it knows about. Perhaps some runways only exist in one direction in its database?

Well... checking the trim controls is a checklist item on the real aircraft as well, and if you accidentally touch the emergency trim controls cycling that SYST/TRIM fuse on the right is the by-the-book procedure for fixing that. The modeling is correct, but I agree that it's a subtle trap, especially if you're just getting started with the aircraft. The manual should be updated to mention that it's a thing that can happen.

Trigger unsafe? Carrying other ground attack weapons?

I was thinking you were mistaken and that the nozzle position indicator was supposed to be just a 1/2/3 thing, but I've checked the SFI again and changed my mind - I think you're right. It's supposed to indicate the total area of the engine exhaust nozzle, and that should change with the thrust setting within each zone. See SFI fpl AJS37 del 1, kap 1, flik 9, sida 19, punkt 3.2.9.2 (page 143 in my PDF).

Only tangentially related, but... the real aircraft automatically disconnects itself from ground power, drops the power connector to the ground and closes the hatch all on its own as soon as the generator is delivering power. I guess it's an engine limitation in DCS preventing that from happening in the sim :/

why isn't there a keybind and an animation for this leatherneck please

If you have a proper target fix you'll also get the timeline and aiming guidance in the HUD so you don't need to go head down to know when to fire, so it's definitely handy to do that if you have the time. Not necessary though.

You don't need to do anything to successfully kill ships with the rb 04. I'm serious, you can literally just point the plane at the ship - visually, if you want - unsafe and fire, and there you go, it'll launch and track. You don't need to prepare the nav system (it doesn't even need to be working at all), you don't need to have the radar active, you don't need to set QFE, you don't need to switch to ANF mode... zip, zilch, nothing. As long as you're within permitted release parameters (mainly altitude) and the aircraft attitude gyros are working, you're good. Or, well, you have to ensure you're in range, but that's not really much of an issue. The missile is entirely self-contained and doesn't care one whit for whatever you're up to. It has no navigation system other than course and attitude gyros (the reason the aircraft gyros need to be working is that the missile's gyros are slaved to the aircraft's until release and a gyro fault will inhibit release IIRC), but it does have its own radar and radar altimeter and completely ignores whatever is going on in the aircraft's systems. The targeting principle is just "fly in a straight line and lock on whatever's ahead". It's an incredibly forgiving weapon, especially for its time. edit: RaXha got there first, again

There is an extensive discussion of this exact problem in the aerodynamics compendium, see page 38 and onwards in the PDF (printed page number 42) and also note fig. V.11 on page 42 (printed page number 46). That last figure is for landing but shows just how limited maneuvers you can do at high alpha and low speed, even with a very light aircraft. My understanding is that yes, this is fairly realistic modeling. At low speeds and high alpha you're not only seeing induced drag but also less thrust because of losses in the intakes. So, yeah, don't over-rotate.

B in the destination indicator = "brytpunkt", waypoint. E in the destination indicator = "egenfix", fix on own position. If it's showing E1, it means you've pressed the fix trigger on the radar stick to the first detent (T1), and the computer is waiting for you to verify the actual position of waypoint B1 optically by overflying it and pressing the fix trigger to the second detent (TV) at the appropriate moment (when you're right above it). While it's in "waiting for fix to be completed" mode, automatic waypoint switching is inhibited, and that's what it's trying to tell you with the E in the destination indicator. Once the fix is complete, the computer will automatically switch to next waypoint. The other possible letters in the destination indicator's left window are: M - "mål", target. Waypoint is a target waypoint. L - "landning", surely you can guess what that means. Waypoint is a base; if it's the takeoff base the right window that usually has a number in it shows S ("start") instead. If the L is blinking, that means "opposing runway heading". LB - "landningsbrytpunkt", landing waypoint, or perhaps more appropriately and easier to remember, landing, base (as in base and final). LF - "landning, final", again this should be obvious. Waypoint coordinates is the touchdown point. U - "upptagning", pop-up. Letter is shown in red and is the pop-up point for certain types of weapon strikes. R - "ruta", box or rectangle. Used in the recon mode (master mode SPA) for defining target area borders, not sure if this actually works in DCS. Haven't tried it. S - "skugga", literally translates to shadow. Used in the recon mode when periodically measuring target position with radar to establish its course and speed. Again not sure if this is implemented.