109K Convergence Question

[Baumer]

I didn't know if I should post this in the bug forum or in here for the 109 experts. I was trying a different convergence for the 109K-4 for some bomber interception and I ran across some interesting results. Normally I'd have the convergence set at 300 but I wanted to see what 650 would look like.

The tests were conducted at 2000ft and 300mph (true). Each round was fired individually (to the best of my ability), and I waited until the speed stabilized after each shot before firing again.

The first image is with the convergence and target at 300 yards.



The second image is with the convergence and target at 650 yards.



I understand that the Mk 108 ballistics were horrible, but my question has to do with the main grouping being low at 650 yards.

Was there a limit to the convergence adjustment in real life?

What was the convergence set at back then? I have the Fw190A-8 manual and I know the recommended convergence is very different than what we can do in the game.

Just curious, Thanks

Baumer

[moot]

I think I saw historical convergences pretty far out for both the 151/20 and the 108.  I know was pretty surprised at the distance, but I can't remember what they were.  I think 20mm were out to 400m.

Re: discrepency between your convergence and the .target range, maybe your gunsight is the problem.  You were doing this with level-autopilot on right?  The plane was settled into stable level flight, constant speed ?

[Baumer]

yep auto pilot, one round at a time (a couple double sprites) and settle for 5 to 10 seconds between shots. With a steady speed of 300mph TAS and 2000 feet.  Perhaps I should retry it at a higher altitude?

If I was going to continue at 650 yards I probably would edit the sight for the discrepancy but I was just curious.

That got me to thinking about how much mechanical adjustment was available. 

[Noir]

I wouldn't be surprised if they put a long convergence on the 190's hunting bombers...you don't want to get too close from a B17 I think

I'm not surprised with the 30mm trajectory either, except the few shells that went totally out of sight. I can't think of any reason for it right now.

[BaldEagl]

yep auto pilot, one round at a time (a couple double sprites) and settle for 5 to 10 seconds between shots. With a steady speed of 300mph TAS and 2000 feet.  Perhaps I should retry it at a higher altitude?

If I was going to continue at 650 yards I probably would edit the sight for the discrepancy but I was just curious.

That got me to thinking about how much mechanical adjustment was available. 

Your pic looks about right.  I keep the guns on the 109K-4 and the 190A-8 at 650 in case I run into buffs and that's just about how much I have to shoot over the target to hit although I'm usually firing by D800.

[Xasthur]

I wouldn't be surprised if they put a long convergence on the 190's hunting bombers...you don't want to get too close from a B17 I think

I'm not surprised with the 30mm trajectory either, except the few shells that went totally out of sight. I can't think of any reason for it right now.

It was the opposite, actually.

The Sturmgruppen fired their guns at 200 meters for the 20mm and 100 meters for the 30mm cannon.

This was the regulation practice for the heavily armoured 190A8s that would fly straight up behind the heavy bombers in tight, arrow-head formations.

The previous technique of a '12 o'clock high' approach also required convergences at similar ranges, the aft approach just allowed more time to really hack vital parts off bombers and failing that, ram them.

The aim of the forward quarter attacks was to kill the pilot as it was much easier to do that than to hack the wings off the nigh-indestructable B-17s, initially.

In fact, the Luftwaffe had a lot of trouble getting their pilots to 'hold their nerve' and get close enough to the bombers... Even when they filled the windscreen they were still too far out. That's why you see so much gun camera footage of pilots lobbing rounds at bombers from a really long way out.... it was a big problem for them. Inexperienced pilots didn't know when to break off and would do so far too early.

The forward quarter is the most effective as far as danger and ammo expenditure is concerned in Aces High as less than 5 rounds from a 109 (with convergence set at 200 yards) is enough to take out a B17 provided your aim is true.

I also find that a steep angled high six approach where you 'lob' the rounds in front of the bomber in order for the rounds to drop onto the top of the cockpit works well too. A high speed approach is necessary for this to be a 'safe' attack, though. This method also takes less time to 'reset' than the head-on attack that requires you (in my experience) to extend out in front by at least 2.0k in the 109, 3.0 - 3.5 in the Fw 190. You can also successfully set up a high speed, low 6 attack (aiming for engines, wing-tips and fuel tanks) as you come back up from the high-6 attack. If you're fast enough you'll be difficult to hit.

Back on topic, I've asked this question many times myself and the general consensus from the very best 109 sticks is 200 yards.

My convergence for the Mk 108 equipped aircraft is as follows:

109: 30mm - 200
       13mm - 600

190: All cannon - 300
       13mm - 600

262: 30mm - 400 (to allow for the typically higher closure rates)


For a very helpful discussion on this matter, focusing on the 109, check out Agent360s outstanding explanation here: http://bbs.hitechcreations.com/smf/index.php/topic,238513.0.html

[Trikky]

Interesting thread. Been some time since I logged on and cant offer anything other than the anecdotal. As for convergence, I remember reading something from the game designers that bullet drop/lead is calculated according to altitude? Either way, the guy we need here is Mr Williams with his encyclopedic knowledge.

[Baumer]

Thanks for the feedback. I have the convergence table for the Fw190A-8 R-1 and it's rather interesting.




In practice the MG131's don't converge at all, they were set to be parallel and they cross the sight center at 30 meters and again at 400 meters.

The R-1 package was with the twin Mg151/20 gondolas, for a total of 6 Mg151/20's with 1000 rounds total. They are set to the following convergence and sight center.

• wing root pair converge at 600 meters and cross sight center at 130 meters and again at 550 meters
• inner gondola pair converge at 800 meters and cross sight center at 140 meters and again at 550 meters
• outer gondola pair converge at 900 meters and cross sight center at 145 meters and again at 550 meters

[Stoney]

IIRC from another thread I started last year sometime, I found documentation on this site that showed the Mk108 in the 109 factory set at 400 meters.  Since it fired through the hub, it couldn't be adjusted in the field.  How that's treated in game, I have no idea.

http://www.luft46.com/armament/mk108.html