corvinus

Must be, if there is no weight on the wheels then the system thinks it is safe to retract the gear. Just check this again when the fix comes in.

+1

Azimuth beamwidth of the radar is about 1.8o. At 5 km that leads to a resolution in cross range (perp to your path) of about 160 m. At least this is the rough estimate of the resolution. Being a runway width off, does not sound so bad. In this thread there are more ramblings about RR mode: https://forums.eagle.ru/showthread.php?t=217707 These are mostly about the range error. If you use a waypoint all is fine (technically this is NAV bombing), but if you rely solely on the radar 3 km distance line then, in open beta, you will find that this distance is not placed correctly: https://forums.eagle.ru/showpost.php?p=3592944&postcount=24

Do you select IR-RB on the weapon selector or do you use the fast select button. I've found that if I: 1. Set weapon selector to IR-RB. 2. Master mode to ANF. 3. Radar to A1, 15 km. 4. Point plane at target. 5. Press Tv Then I get a proper attack HUD symbology (see screenshot) with a distance line countdown, which helps if you want to fire the RB-74 at maximum range. When I use the missile fast select button, then none if this works. Only when I dial the weapon selector to IR-RB, I get the proper HUD symbology. Also note that I use Tv instead of T1 (the manual says T1 btw, but that doesn't work for me).

I can confirm both issues. Apparently I was in ANF master mode.

If by "off" you mean that the central indicator goes dark, then this probably means that the radar switches from ground mapping to ranging mode. It should provide you a range, although I do not know where to read off or use this range. Anyhow, it does suggest you had a succesful radar lock.

Here they still work (all three variants of the RB-75). Perhaps your controls got messed up after the update? That has occurred in the past.

Sorry, but I can't load the track due to an enabled mod (range targets).

No tail strike for me, however I find the plane a bit sensitive during takeoff, but being rather new to the Viggen I cannot say if it is normal or not. Perhaps you can post a track?

No need to feel dumb, this was still a useful discussion! Moreover, it led to the discovery of a bug!

I see, remember the RR modes has two submodes: radar release and nav release. If you time your trigger moment on the distance indicator gauge you are essentially doing a nav release kind of thing. This also works for me. Try to remove the waypoint and see if you can hit the target ;-) Without a waypoint you have to use the PPI only (no distance indicator guage to help you). As the 3 km indicator on the PPI is a bit misplaced, the bombs fall long.

You're welcome!

This is how I understood it from the manual. Imho the 3 km cross does not correspond to 3 km, I checked this by placing a waypoint. The distance indicator gauge indicates 3 km before the 3 km distance line in the PPI is over the waypoint. What do you make of the screenshot below? The plane is at 3 km distance from the waypoint, but the PPI 3 km distance line is not at the waypoint. Doesn't that mean that the PPI distance line is not placed correctly? Note that this is after a few minutes of flying, so I don't think INS drift is an issue here.

Sorry to get back at this point, but it is not clear if you use the PPI or the distance indicator gauge (top-right front panel) to determine if you are at 3 km distance.

Thanks for your reply, excellent suggestions! This is a good point, I'm flying about 280 m/s, and the update time is a bit less than a second. So if your radar image is 1.0 s old you are 280 m too late. The error I'm getting is in the order of 800 m, which cannot fully be explained by latency issues like this. In the 15 km setting the pulse length is 0.5 microseconds. If the radar does not use pulse compression that would set the range resolution to about 75 m. If the radar does use pulse compression (I'm not sure if that was common in that era) then the radar resolution would be even better. So one can safely say that the range resolution is better than 75 m. Now if you add the two errors the maximum error is about 350 m, which is significant if you want to hit a ship. Did you also try this with the latest openbeta update? I'm asking because if I use the B-scope, the 3 km line in the B-scope seems way off. Therefore I am also a bit suspicious of the placement of the 3 km in the PPI. I think it was correct before the update, but I'm not sure.

Thanks for the track! I've watched it and you will be glad to know that on my system the bombs also fall on target. It is however impossible to see when you pulled the trigger. I've duck into the cockpit in order to see the trigger, but I think the button is not animated. So the big question is: Did you pull the trigger when the waypoint distance indicator (the gauge on the top right of the front panel) indicated 3 km, or when the reticle in the PPI was at the western edge of the island? If I use your track and take control after you did all your settings and altitude corrections, the bombs still fall too far if I base my triggering purely on the radar echos. Mind you, the target area crosses the 3 km line on the PPI, I'm almost directly above the target. Regarding your other remarks, they are correct I think, but in this case it doesn't matter much (the target area being almost at sea level). Also the commanded height is a safety height, the computer uses actual height for bomb release computations afaik. So to summarize: * If I base triggering on the PPI => bombs fall long. * If I base triggerin on the waypoint distance indicator => bombs fall on target. For me that leads to the conclusion that the 3 km indicator on the PPI is not placed correctly.

Thanks for looking into it, much appreciated! Btw, the radar does not actively "detect" the target, i.e. it does not lock on to anything like the F-18C A/A radar. For the Viggen it is up to the pilot to interpret the radar echos.

So here I am again with some more info. This time I used the B-scope in the 15 km setting. I flew towards the waypoint which is centered exactly over the target, which is on the small island located in the delta of the river. The distance to the waypoint is 0 km, so I'm exactly over the target. However the B-scope shows the island at a distance of about 10 km!

Exactly! If I release when the tip of the reticle (and thus not the center) is over the target, then the bombs fall way short ... When do you pull the trigger (so where is the radar reticle in relation to the target)? Mind you forget about the waypoint circle, that is just to help me measure the proper distance to target. Also, how do you explain that (when using the helper waypoint), the distance indicator shows 3 km before the reticle center is over the waypoint center? It would help if you can post a screenshot showing the PPI and the distance indicator at the moment you pull the trigger. Then we can confirm if I just release at the wrong time, or we are actually not running the same version a bug was introduced.

Ok, here is a new track. Different target now, just a few static structures. Same result though, bombs fall long of the target (I confirmed that the target is not destroyed by checking the target afterwards). To me it seems that the 3 km line on the PPI is not placed correctly. I think I am pressing trigger at the correct moment, am I not? Any help and pointers are much appreciated! AJS-37 radar release 2.trk

This is what the manual says: "Trigger pulled and held when the target radar return passes the firing range line at 3 km." There is no reference to a waypoint, which is not needed in this mode. I only used a waypoint to be able to compare the range at which the 3 km line on the radar screen is over the target. I think this should be at 3 km if the waypoint is directly over the target, but it seems not to be the case. Anyway, I will make a new track because this track is apperently only complicating things. I checked Chucks guide (thanks for the tip). The text is not very clear to me: "When radar return or target point circle passes the firing range line, drop bombs by pressing and holding continuouslythe Weapon Release button until the FALLD LAST (STORES RELEASED) light illuminates." But IF you use a waypoint (=target circle?) then the target radar echo should be in the center of the circle. I think Chuck refers to the reticle when he talks about target point circle. Nevertheless I will try this and see what happens.

Will check this tomorrow. Btw, the target is very high so a slight change in bomb height during the ballistic fall could make the bomb hit the tower or not. I will make a track with a smaller ground target.

The target is really still there. The screenshot is created using F12 (which placed the camera at the TV tower site, I then zoomed out to create the screenshot). In the screenshot you cat see that the bombs fall in the water, I also see that after using F6. If I use NAV release (put the waypoint on the target and fly towards the waypoint with weapon selector at RR and master mode NAV), I do hit the target. So the INS is still correct. However if I use master mode ANF then it doesn't work. I noticed that when the distance to the waypoint is 3 km the reticle is not over the waypoint! It seems that the reticle is not placed corectly. See screenshot below.

Hmmm, that is interesting. I'm running Open Beta, what version are you running? Concerning my problem. If I watch the track from the TV towers perspective, this is what I get: The bombs fall far from the tower ...

For other bombing modes this is true, but for the RR mode the manual states: - Mode ANF. Commanded altitude = Safety altitude - Trigger UNSAFE. - Trigger pulled and held when the target radar return passes the firing range line at 3 km. I.e., the trigger is pulled when the reticle is above the target. Mind you, the reticle is fixed (i.e. you cannot move it, it is always at 3 km distance).