Gun convergence on Bf 109

[U505]

Hi mates
Since the release of the game i read about spitfire's guns convergence but not reallyabout bf109's.So i let it without any settings but i have the feeling to waste my munitions and it is very difficult to shot down an ennemy plane. Have you set any values? Do you take case of the canons on the E4? your help would be much appreciated for me and a lots of pilots in order to clarify this point. :-P

[SlipBall]

I think the stock setting will work just fine, but it does take practice to develop the skill. Really a matter of holding your fire till you are at a good distance to get a high hit ratio.

[zapatista]

U505

the most important issue with wing-gun convergence is knowing exactly how far the enemy plane is from you, and obviously knowing what convergence distance your wing guns are set at, typically somewhere between 100 and 300 meters, with most preferring somewhere between 150-200 meters. if your convergence is set past 300 meters, much of the munitions energy is lost over the distance, and hit impact will be less (historically correct principle, and i think this energy loss is modeled in il2/CoD series). one reason the polish squadron was so effective in BoB, other then most of them being very highly trained pilots, is that they set their convergence very short at 125 or 150 meters, and would maneuver quickly very close to the enemy plane and then take their shot (making their munitions more hard hitting, and more accurate). a convergence setting is obviously not needed for nose canons, but i believe you could set elevation for some of these nose cannons on certain aircraft. similarly you can set an elevation convergence setting for wing guns, but that is mostly relevant for distances past 300 meters iirc

to learn to recognize how far exactly the enemy plane is from you, read some articles and pilot instruction manuals about using the gun-sight reticule to determine plane distances. typically you set it to the known fighter size of your opponent at a given distance (eg his wing tip will fully fit in the reticule at for ex 200 meters), and then you know by looking if the enemy plane is smaller he is further away, and if larger, he is closer by. then you know that if he is exactly at the right distance from you, all your munitions will hit one small area, if he is closer they will hit on either side etc..

also, look up dome information of deflection shooting, since rarely will you ever have the luxery of sitting right behind an enemy plane at a fixed distance from you and shoot squarely at him for any length of time. with deflection shooting you have to hit him from the right distance AND with the right amount of "leading" (shooting in front of him) so he flies into your gunnery trail

lastly, with the right distance and the right convergence setting, and with the right deflection shooting skill, you still need to aim at some specific vulnerable parts of the aircraft to be effective, eg the cockpit with the pilots, the engines themselves, or the wing roots. often just vaguely shooting into the fuselage itself can be very ineffective, since you dont his any vital parts. there is specific info for various aircraft as to what their specific weak points are, eg for the old il2 sturmovik aircraft for the engine you had to try and hit the oil cooler from underneath the plane, because the engine had armor protecting it from other angles etc

thats the main principles, you might need to do some reading on the subjects to get a more comprehensive idea. eg for attacking bomber formations, read up on the historical tactics used by attacking planes to minimize risk to themselves and make it more effective, the same tactics can be used in CoD/il2 series

[U505]

thank you very much zapatista. It is a very interesting post in wich a lots of us can learn more :grin:

[lonewulf]

Well, without wishing to appear argumentative, I'm not so sure I would agree with some of Zapatista's comments. Firstly, the reference to the success of the Polish squadron seems to presuppose that the members of other squadrons set their convergence at much greater ranges. Is there actually any evidence to support this?

Secondly, the statement "a convergence setting is obviously not needed for nose canons, but i believe you could set elevation for some of these nose cannons on certain aircraft" worries me, in fact, I don't follow it at all. Most 109s , for example, had either 2 or 3 centrally mounted forward-firing weapons. These were comprised of a cannon of 15-30 mm (if installed) and two machine guns of either 8 or 13 mm. Because the trajectories of those weapons differ, to be effective, they will have to be harmonised to converge at a predetermined range. Even if you dispensed with the machine guns, you would still have to make a decision about what range you wished to sight your cannon for. Cannons, like MGs, have a trajectory, so the cannon must be adjusted to ensure it's projectiles fall through your line of sight at the desired range - rather than below it or above it.

fFnally, the advice concerning a selected aiming point: "aim at some specific vulnerable parts of the aircraft to be effective" worries me also. There's no doubt that from time to time a WW 2 combat pilot would have the luxury of aiming at the pilot or an engine or even the fabled 'petrol tank behind the pilot's seat' but in general, such precision shooting is completely unattainable under combat conditions - especially in twisting turning fighter on fighter engagements where high deflection angles are often involved. In these circumstances, just hitting the aircraft can be a small miracle let alone killing the pilot or shooting the tops off the spark plug leads.

On a related point, I am still at a loss to understand the separate convergence values that can be inserted in the loadout section of the sim for each weapon. If I select 200m for the horizontal value, how is it possible to insert say 500m for the vertical convergence value. If someone is able to explain how such a setting would be physically possible, I'd really like to know.

[Varrattu]

Since iL2CoD-v1.05.15950 the standard convergence for all BF109E is defined as follows:

nose mounted MG 2x Rheinmetall-Borsig MG 17 (7.92mm)
vertical convergence == 400 m (Visierschuss)
horizontal convergence == 420 m (Kreuzung)

wing mounted MG 2x Rheinmetall-Borsig MG 17 (7.92mm)
vertical convergence == 500 m (Visierschuss)
horizontal convergence == 300 m (Kreuzung)

wing mounted MG 2x Oerlikon/Ikaria MG FF (20mm)
vertical convergence == 500 m (Visierschuss)
horizontal convergence == 300 m (Kreuzung)

wing mounted MG 2x Oerlikon/Ikaria MG FF/M (20mm)
vertical convergence == 500 m (Visierschuss)
horizontal convergence == 300 m (Kreuzung)

There is a good reason why vertical standard convergence is 500 m (Visierschuss). The German iL2CoD munition types have been animated in a version "verbessert" (improved). The cartridges are of high-velocity type for maximum performance in aircraft machine guns and give higher pressure than other 7,9 mm rounds.


Please have a look:

http://forum.1cpublishing.eu/showthread.php?t=24547

http://forum.1cpublishing.eu/showthread.php?p=396572#post396572

~S~ Varrattu

[SlipBall]

On a related point, I am still at a loss to understand the separate convergence values that can be inserted in the loadout section of the sim for each weapon. If I select 200m for the horizontal value, how is it possible to insert say 500m for the vertical convergence value. If someone is able to explain how such a setting would be physically possible, I'd really like to know.


This is a very easy concept to visualize...your friend is a good distance away from you. You want to hit him/her with a snowball, you realize that you need to give a greater angle upwards when thrown, so as to not fall short and to make that hit.:)...drag/gravity!

[VO101_Tom]

...(eg his wing tip will fully fit in the reticule at for ex 200 meters)...

This is true only, if the plane wingtip is 20m (medium bombers). The fighters wingtip is ~10m, so if you see a fighter, which wingtip fully fit the circle, it is 100 m distance.

U505
very simple the calculation: wingtip meter X how fit into the circle X 10 = distance

You can download the Horrido - Des jägers Schiessfibel engish translated document from here: http://www.mission4today.com/index.php?name=Downloads&file=details&id=3663. Read it, you will learn everything, what you want to know from air gunnery (it was published in 1944).

I think the bigger problem is the inaccuracy of the guns. Now totally unnecessary playing with any convergence settings, if the gun just shots around the target:

http://youtu.be/2EBTP6IEUbU


(I was landed with 30° Flap, retracted gear, so the 109 nose pointed low enough to able to compare the shots with the canvas. The distance is 100 m (measured in the FMB). The function and using of that canvas explained here: http://forum.1cpublishing.eu/showpost.php?p=359128&postcount=10

[VO101_Tom]

...
On a related point, I am still at a loss to understand the separate convergence values that can be inserted in the loadout section of the sim for each weapon. If I select 200m for the horizontal value, how is it possible to insert say 500m for the vertical convergence value. If someone is able to explain how such a setting would be physically possible, I'd really like to know.

Maybe this explain :cool:

http://www.pumaszallas.hu/Private/VO101_Tom/bugtracker/convergence_explanation.jpg

[vranac]

I think the bigger problem is the inaccuracy of the guns. Now totally unnecessary playing with any convergence settings, if the gun just shots around the target:

http://youtu.be/2EBTP6IEUbU


(I was landed with 30° Flap, retracted gear, so the 109 nose pointed low enough to able to compare the shots with the canvas. The distance is 100 m (measured in the FMB). The function and using of that canvas explained here: http://forum.1cpublishing.eu/showpost.php?p=359128&postcount=10

Tom, did you look that track from outside view?
Maybe your plane is shakin a bit because of cannons shoting.
I think plane was fixed somehow when guns was adjusted on target.
If I remember right some picture was shown here from desert and two mechanics were sitting on wings of the plane to stabilize it.

By the way very good idea 8)

[lonewulf]

Sorry, none of the above helps me. I'm still not getting it I'm afraid.

vertical convergence == 400 m (Visierschuss)
horizontal convergence == 420 m (Kreuzung)

Ok, as an example, let's use the values listed above. But before that can I just stress that we are only concerned with convergence here, not burn-out and not fusing.

To remove any inconsistencies with the grouping we get from our guns let's assume for the purposes of the test that we have perfect weapons being fired from a perfectly stable gun platform. Ok, so in this case we adjust all of our forward firing weapons to converge at a range of 400m in front of the aircraft in the vertical plane. Now, because we have perfect weapons etc the projectiles should all go through a single (ragged) hole at exactly 400m in front of us. Ok, so far so good. Now we introduce our slightly different horizontal convergence value. In this case that's 420m. Right, so now we appear to have a problem, at least as far as I'm concerned. How can our perfect weapons fired from a perfectly stable gun platform put a single (ragged) hole in two different points in space at the same time? Do our guns converge at 400m or 420m, which is it??

Slipball, you said; "This is a very easy concept to visualize...your friend is a good distance away from you. You want to hit him/her with a snowball, you realize that you need to give a greater angle upwards when thrown, so as to not fall short and to make that hit....drag/gravity!"

Ok, so are you suggesting, if we go back to the sim, that for your projectiles to converge at 400m in front of your aircraft they would have to be fired along a trajectory with a 420m high-point above the line of sight? If you are suggesting that, then I think you're seriously mistaken.

[VO101_Tom]

Tom, did you look that track from outside view?
Maybe your plane is shakin a bit because of cannons shoting.
I think plane was fixed somehow when guns was adjusted on target.
If I remember right some picture was shown here from desert and two mechanics were sitting on wings of the plane to stabilize it.

By the way very good idea 8)

This pictures?
http://www.pumaszallas.hu/Private/VO101_Tom/bugtracker/f195_shooting_range_2.jpg

http://www.pumaszallas.hu/Private/VO101_Tom/bugtracker/f195_shooting_range_3.jpg

Look, i admit it would be the best, if the devs would give us a lifting device. All i can do now, I landed with retracted gear, and set the flap to 30 deg to lowering the nose (and turn off the head shake in realism). I think it should be stable enough :cool:
Anyway, if the plane shaking, then should shake the revi too, but no. It was very stable. We should see a single tracer line, but we have this:

http://www.pumaszallas.hu/Private/VO101_Tom/bugtracker/gun_acc_01.jpg

The weirdest picture is this. If a mounted (!) gun (not cannon, just a 7,92 mm machinegun) would be this accurate, then all army use bow and sword until today :rolleyes:
http://www.pumaszallas.hu/Private/VO101_Tom/bugtracker/gun_acc_02.jpg

[skouras]

i use 250 yards[228 meters] for cannons
it just works great for me
not to close not to far

[VO101_Tom]

Sorry, none of the above helps me. I'm still not getting it I'm afraid.

vertical convergence == 400 m (Visierschuss)
horizontal convergence == 420 m (Kreuzung)

Ok, as an example, let's use the values listed above. But before that can I just stress that we are only concerned with convergence here, not burn-out and not fusing.
....

I think you mixing things.
Vertical convergence means the distance, when the bullet trajectory will crossing the center of the revi sight.
Horizontal convergence means the horizontal alignment relative to the center line of the Revi.
If the two value is different, then you see the bullet crossing the revi center in vertical, it have differences in horizontal:

this is what you get, if the setting:
MG17 - 400m hor. 400m vert.
MG FF - 200m hor. 400m. vert.

200m:
http://www.pumaszallas.hu/Private/VO101_Tom/bugtracker/revi_convergence_2.jpg

400m
http://www.pumaszallas.hu/Private/VO101_Tom/bugtracker/revi_convergence.jpg

[lonewulf]

Thanks Thom, I've just now had an opportunity to look at your diagram. That helps explain quite a bit although I'm not convinced that what is provided is all that practical. Essentially the arrangement as described in the diagram provides effective dispersion rather than actual convergence. In the case described, the weapons do not converge at any point. The individual weapons group roughly together at 200m but the MG don't actually converge until 400m at which point the cannon rounds have reached a horizontal spread of 4.5m. At 450m the cannon rounds are probably about 15-20m apart. I'll have to go back to the information provided by Varrattu but I'd have thought to be used effectively you would have to know the exact trajectories of the 7.92 and the 20mm at given ranges. For example, at 200m the weapons all group roughly the same but at an undisclosed distance above the line of sight. So essentially at the point where the projectiles are at their closest, they are also striking above the target. If that's a few cm that's fine but given the low velocity of the 20mm FF cannon compared to the higher velocity 7.92 mm round that seems unlikely. And given that physics are what they are, only certain figures could be used as vert. and horizontal values. If you used something else, the trajectory of the weapon would be distorted, I'd have thought.

Anyway, thanks for the info. I suspect that answers my questions.

[vranac]

This pictures?


Look, i admit it would be the best, if the devs would give us a lifting device. All i can do now, I landed with retracted gear, and set the flap to 30 deg to lowering the nose (and turn off the head shake in realism). I think it should be stable enough :cool:
Anyway, if the plane shaking, then should shake the revi too, but no. It was very stable. We should see a single tracer line, but we have this:





Yes,that picture.
I agree with you, but look carefully at 0.06 and 0.11 at your video.It looks
to me that plane moved a bit, because of that I asked you did you look that track from outside view.

I noticed that especially with cannons momentum they provide is huge.
I have one track with damaged one wing and cannon which shows how hole on the wing impact flight(had to compensate with rudder)
Then I tried to shoot at passing plane.Result was a disaster :grin:


The weirdest picture is this. If a mounted (!) gun (not cannon, just a 7,92 mm machinegun) would be this accurate, then all army use bow and sword until today :rolleyes:
:) strange

@lonewulf
Best way for you is to try it yourself. Shot at planes with icons enabled to see distance and record track.You will see where tracers cross.
Then set it to distance on which you shot most of the time.

It is not easy to shoot precise with cannons but I know some guys that damaged my plane hard 95% when they pull the trigger )))
And that from very hard angles.
Practice,practice,practice...))