Well, you may have guessed that it’s indeed the Ram Air Turbine, designed to give AC power to the aircraft in case of an electrical failure of the main generator.
It’s affectionally called ”Millan” in the SwAF.
The fact that it opens on ground is that the area inside the RAT contains HYD, O2 and other consumables. It also houses the fire extinguisher port for the starter motor. So ground crew need access to this area and since the RAT hatch is hydraulic powered, there is some fool proof logic that prevents it from closing when the aircraft is on ground.
It used to extend and retract with the landing gear, but this led to fatigue cracks in the blades that could shear off and by the infallable law of Murphy meant that they punctured the HYD accumulators. So the logic was modified to extend the RAT with nose gear compression. Still retracts with gear though.
Ahh. Ok. That makes sense. I thought it might just be open until held in. I am wrong 
Another added advantage is that it allows ground crew to quickly survey the state of the backup turbine without any tools. For a attack aircraft operating from highways and hidden bases manned by minimally trained staff this is probably a positive feature.
No comment! 
Hey! 
You obviously hand disassembled the Viggens for fun
We got to do engine swaps, in the field. That was pretty cool! Always a technician present though.
I tried that last summer! 
At first I was 
, but then I 
[https://www.reddit.com/r/hoggit/comments/gegmrm/stridsvagn_37/?utm_source=share&utm_medium=web2x]
Awesome!
Hahah love it…the Swedish do love their turretless tank designs…
Quick Viggen question. What is the meaning of the numbers on the tails of the default Viggen skins?
From top to bottom of the paint scheme selection menu: 37, 64, 02 (also on wings) and 76.
Side number (Bort Number) / Tail number or Squadron Number?
The number on the side of the nose is Flottilj or Flygflottilj (The closest i have gotten to a translation is FighterWing) The tailnumber is an individual airtcraft number.
Happy Simming
Oooh…camera pod with night illumination! Want one! 
I did a teeny tiny little logbook fix to allow me to progress the Mjolnir campaign. I just passed the third mission. Although everything went reasonably well my wingmen decided that they were not confident in the RB-04’s capabilities, and opted to load AS.34 Kormorans instead. Is this a known bug?
The number on the nose does indeed denote Flygflottilj and is usually translated to Airwing, as there may be other squadrons besides fighters.
The Airwings used to get their callsigns from the swedish phonetic alphabet.
F5 is Erik
F6 is Filip
F7 is Gustav
F10 is Johan
F15 is Olle
F16 is Petter
F17 is Quintus
F21 is Urban
To name a few.
The squadrons are denoted by color.
1st is Red
2nd is Blue
3rd is Yellow
4th is Black
5th is White
The aircraft had individual tail numbers and the callsign for each aircraft was the Airwing callsign and aircaft number. F15 Airwing aircraft number 06 was ”Olle 06”.
These days each of the few squadrons that are left have their own callsigns.
Airwing F7 1st Squadron is now 71. Squadron.
71. Squadron callsign Spider
72. Squadron callsign Ghost
171. Squadron callsign Aquilla
172. Squadron callsign Gator
211. Squadron callsign Wolf
212. Squadron callsign Dalton
OK!!! I see some awesome fixes in the latest Beta update…time to take this puppy out for another fascinating ELINT mission! State tuned!
The improvements to the ELINT pod - specifically listing the Last Signal - work well. Plus I seem to have detected/recorded more radars than before (same mission, radars, flight plan) - could be I used a different sensitivity setting on the pod …? Regardless I got good results:
ELINT:
Emitter: 1
Freq: A PRF: 400
First signal: 6:33:15 Last signal: 6:40:39
Sequence broadca: 1.5s Silent: 8.5s
NW: 26:24:39 055:21:06 SE: 26:23:41 055:21:27Emitter: 2
Freq: A PRF: 447
First signal: 6:33:16 Last signal: 6:40:5
Sequence broadca: 1s Silent: 2s
NW: 26:16:26 055:15:25 SE: 26:16:27 055:17:07Emitter: 3
Freq: A PRF: 967
First signal: 6:35:5 Last signal: 6:40:14
Sequence broadca: 1s Silent: 2s
NW: 26:20:05 055:01:34 SE: 26:19:44 055:01:35Emitter: 4
Freq: A PRF: 697
First signal: 6:36:4 Last signal: 6:40:2
Sequence broadca: 1s Silent: 2s
NW: 25:51:39 054:59:49 SE: 25:51:39 055:00:44Emitter: 5
Freq: B PRF: 10000
First signal: 6:36:30 Last signal: 6:40:5
Sequence broadca: 1s Silent: 2s
NW: 27:12:55 055:14:32 SE: 26:18:17 057:46:36Emitter: 6
Freq: B PRF: 7893
First signal: 6:36:57 Last signal: 6:40:45
Sequence broadca: 1s Silent: 2s
NW: 26:13:53 055:08:13 SE: 26:13:50 055:11:18Emitter: 7
Freq: A PRF: 1110
First signal: 6:39:22 Last signal: 6:39:53
Sequence broadca: 1s Silent: 5.2s
NW: 28:16:52 055:11:28 SE: 26:17:41 057:43:21
The Silkworm CDCM FC radar is “new” and so isn’t listed in the database
. Previous testing I did gave a PRF of 1000 so that is what Emitter 5 & 7 must be. They (2 sites) are also located within their boundary boxes so it was good hits, especially given their short collection time and distance from the jet.