Convergence

[Muff_Huggar]

I'd like to learn a little about gun convergence. By default, the guns in FC have a convergence of 400 meters. Was this a standard in real life? Did pilots/mechanics adjust the convergence before they left the ground based on the mission they were going to fly? I could see where a "longer" convergence (say 600 meters) might be "better" for attacking ground targets and a "shorter" convergence for dogfights. Or was the convergence set by the pilot based on his personal preference and flying style? Could this be done "on the fly" from the cockpit or did it have to be done on the ground in a test area? 

[Herne]

33 minutes ago, Muff_Huggar said:

I'd like to learn a little about gun convergence. By default, the guns in FC have a convergence of 400 meters. Was this a standard in real life? Did pilots/mechanics adjust the convergence before they left the ground based on the mission they were going to fly? I could see where a "longer" convergence (say 600 meters) might be "better" for attacking ground targets and a "shorter" convergence for dogfights. Or was the convergence set by the pilot based on his personal preference and flying style? Could this be done "on the fly" from the cockpit or did it have to be done on the ground in a test area? 

 

I had never associated convergence with ww I planes. I'd always assumed straight ahead. If convergence was a thing though, I would have expected it to be close. Like  <150 meters 

[Garven]

1 minute ago, =FEW=Herne said:

 

I had never associated convergence with ww I planes. I'd always assumed straight ahead. If convergence was a thing though, I would have expected it to be close. Like  <150 meters 

The convergence setting effects the vertical also in game.  If your set at 500m you will probably shoot around 3ft high at 100m.

[unreasonable]

Given how close together guns are on the planes that have two there is really no reason to have a horizontal convergence at all but I suppose you get it anyway given the game engine.   For vertical I would go with 200-250 for MGs: the vertical variation over that range is very small, given all the other sources of inaccuracy, so your bullet path will be very close to your eye-line up to 300m.  If you go for a greater distance the divergence over your eye-line will become much more apparent as Garven_Dreis says.  You get no real benefit from having it set to less, IMHO.

[DD_Perfesser]

Convergence has more meaning as the installed guns are placed farther apart.  With centerline guns what you're really doing is sighting in the airplane much like sighting in a rifle.  You want the bullet impacts where your sights are at the chosen distance. 

When the guns are installed the plane would be taken to a test stand and each gun mount adjusted.

Your squadron is predominately a fighter or ground attack unit .... not likely to be the kind of thing you would be changing often

[[APAF]VR_Spartan85]

5 hours ago, DD_Perfesser said:

Convergence has more meaning as the installed guns are placed farther apart.  With centerline guns what you're really doing is sighting in the airplane much like sighting in a rifle.  You want the bullet impacts where your sights are at the chosen distance. 

When the guns are installed the plane would be taken to a test stand and each gun mount adjusted.

Your squadron is predominately a fighter or ground attack unit .... not likely to be the kind of thing you would be changing often

See, now I know it’s extra but wouldn’t it be cool to have a convergence calibration test area...  aircraft set into level attitude on the ground and it’s aimed down range,  ,, 

id love to talk about an aircraft maintenance mini game but meh you can only have so much fun

[Muff_Huggar]

What I found embarrassingly important in this topic was the fact that convergence affects how far above or below the target the bullets will hit. I guess I wasn't thinking and just assumed there was no gravity in WWI and bullets didn't drop...that trajectory was invented some time after the Great War. This is so obvious now that someone mentioned it that I feel somewhat stupid for not considering it at all. 

[unreasonable]

If you shoot at something with a MG at 600m away and the tracers are hitting, then every other bullet is missing - by a long way.  That is in RL at least: adding tracer to bullets changes their ballistics a fair bit.  IIRC firing the old NATO 7.62mm the tracers would fall low and left compared to ball.  I expect this kind of effect is present in almost all tracer ammunition in RL, but I think not in BoX ( ? ), which is a pity in a way, as long range sniping that people complain about would be harder if the ballistics difference was modeled.

[Muff_Huggar]

So, Plank, are you saying that when you change the convergence setting, only the horizontal part is being altered? So, let's say I'm sitting on the runway and I have the convergence set to 200 meters. I'm firing at a target 200 meters away. I have the crosshair in the sight centered on the target so each bullet is going to hit the target at the exact center (horizontally as well as vertically). Now I move the target to 400 meters and set the convergence to 400 meters. I'm expecting in the game that if I again center the crosshair on the bullseye, each bullet will hit the exact center again. But your comment leads me believe that while I may be horizontally centered. no consideration is made to adjust the barrels to account for the trajectory drop of the greater distance. So while I would be in the center of the target horizontally, the bullets would be hitting well below the bullseye?

 

I think you're also saying that because of the tracers, the sights are really just a "suggestion" of where the lead is going to go and that people fly by the tracers and could probably do without sights altogether? 

[unreasonable]

People use the tracers as a guide: that is after all what they are for, no other reason for having them.  If you do not use the sights, however, you will waste ammunition and time since you will miss initially and then correct using the tracers.  Better to use the sights to try to get the first shots on target - if you miss then the tracers will give you an idea of the correction needed. 

 

One thing I am not sure about is if the rear sights on actual WW1 aircraft were completely fixed. On a normal MG for ground use the sights are adjustable: but that is because they would be expected to fire out to 1500m or more. In a WW1 aircraft the maximum range might be 500m, and usually much less. So having a fixed rear sight makes sense, given the limited precision possible for all sorts of reasons and the impracticality of fiddling with a rear sight while in aerial combat.  They are certainly fixed in the game: changing the convergence from 100m to 1000m does not change the position of the rear sight.

 

Similarly I cannot see any difference in the bullet path relative to the sights or the crosswires at these two settings when overlaying screenshots, or with side shots using a fixed camera in the ME. The positions of the guns are also unchanged -  so is vertical convergence modeled at all?  The convergence option  may simply be a holdover from the BoX GUI/engine with no actual functionality.

[LukeFF]

TL;Dr

 

It's really simple, folks: vertical convergence is automatically accounted for as the player adjusts horizontal convergence. 

 

[unreasonable]

I do not believe that is true for FC.  You can set the Dr.1's convergence to 100m or 1000m: the bullet trajectories are indistinguishable in the vertical plane. Given that bullets will drop in the order of 10m over 1000m, if the trajectory was being pitched up to pass the LOS at 1000m this would be clearly visible. 

[unreasonable]

I am not sure it would be worth modeling changes in the physical model of the guns/sights to match adjusting convergence;  in BoX it is not needed since the guns are hidden.  FWIW some sights such as the German Revi do not change with convergence in BoX, correctly since they had no range setting.  You can take a screenshot of a 109 at mission start on the runway with 100m, then again at 1000m, overlay the two images, and see that the illuminated ring position is absolutely identical; but when you fire with a 1000m convergence the shells arc up above the centre of the sight. So vertical convergence is clearly being set there, unlike on the Dr.1

 

So my reading of how to look at this is that the Dr1 guns are fixed in position and the sights are effectively set to zero range; or the LOS of the sights is set parallel to the gun bore to put it another way. Convergence appears to have no effect vertically (or horizontally?). Personally I am just fine with that, given WW1 engagement ranges and lack of wing mounted guns makes convergence pretty academic. 

 

I hope the guns are correctly set up in the Nu-SE5a;  as you say some of the RoF models did not bear close inspection. 

 

 

[J2_Trupobaw]

The solution to covergence question in RoF was to set it to 500m; worked well at all practical distances. FC, we need to wait for S.E.5.a to really see what's happening

[Sgt_Joch]

On the SPAD, I have been testing at 400 and 200 meters but have not noticed much of a difference, but then I usually fire from within 100 meters. 

 

 With the tracers and the low closure rate compared to WW2, it is easy to walk the MG fire onto the target, so convergence does not seem as critical.

[[N.O.G.F]_Cathal_Brugha]

@Plank, nice drawing. As a rifleman and hunter I knew about vertical convergence, hopefully your drawing will help others to understand. 

 

21 hours ago, LukeFF said:

TL;Dr

That is the problem with many people these days. 

[[N.O.G.F]_Cathal_Brugha]

On 9/27/2018 at 7:09 PM, Plank said:

Simple stuff that I would do to my plane if I had the opportunity :

The best WW1 pilots did adjust and sight their guns, also loading their own belts of ammo for their guns to pick the best (manufacturing quality and cleanliness) rounds, and making the belts clean and consistent to help prevent jams.