109 nose cannon

[Perrine]

Bustr,
this is kinda off topic, but do you have any info on k4s that used C3 instead of B4 fuel?
-Ty

It is not known if and how many units had converted to 1,98 ata manifold before that order came, but it should be noted these units, in particular III./JG 27, III./JG 53 and IV./JG 53 were the major users of the Bf 109 K-4 in the Lufwaffe. The other units effected are not known at present, but given the abundance of photograph depicting G-10 and K-4 fighters belonging to other units, marked for C-3 fuel use - a likely sign of the DC engine at 1,98 ata - the boost increase was likely not limited to JG 27 and JG 53 alone.

http://kurfurst.org/Engine/Boostclearances/605D_clearance198.html

[MiloMorai]

It is not known if and how many units had converted to 1,98 ata manifold before that order came, but it should be noted these units, in particular III./JG 27, III./JG 53 and IV./JG 53 were the major users of the Bf 109 K-4 in the Lufwaffe. The other units effected are not known at present, but given the abundance of photograph depicting G-10 and K-4 fighters belonging to other units, marked for C-3 fuel use - a likely sign of the DC engine at 1,98 ata - the boost increase was likely not limited to JG 27 and JG 53 alone.

http://kurfurst.org/Engine/Boostclearances/605D_clearance198.html

It is rather strange that Barbi says III./JG27 is a major user of the K-4, yet his list has III./JG27 flying G-10s. It is best to take what Barbi says with a great deal of skepticism.

[Stoney]

It is rather strange that Barbi says III./JG27 is a major user of the K-4, yet his list has III./JG27 flying G-10s. It is best to take what Barbi says with a great deal of skepticism.

If you hadn't said that, I was going to...   

[Perrine]

It is best to take what Barbi says with a great deal of skepticism.

So as it stands this the definitive source when it comes to 109K+fuel topic, right?
http://www.spitfireperformance.com/spit14v109.html

[bustr]

If you read the 109F manual for installing and using the RZ65 65mm rockets they mention an assumption that the Revi has been adjusted for the 100m H setting to see 7.5cm above the MG151/20 motorkanon 0-datum line at 100 meters. In our game that means if our line of sight between the center of our graticule and the offline target center is fixed then when we fired the 109 20mm motorkanone we should be seeing its rounds hitting 82.5cm below center at 100 yards and the 30mm 93.5cm at 100 yards.

With the MG151/20 the H setting raised the graticule to allow seeing 7.5cm above kanone 0-datum line at 100 meters and the MK108 it was 19cm below that line at 100 meters. In the 109 seriese the Revi graticule was adjusted to a point at 100 meters that would corrispond to an endpoint at 400m describing a point on a level cross line to which the motorkanone rounds idealy would impact. The MG were set to bisect this line harmonised with the motorkanone.

Essentialy they knew the ballistics of the motorkanone fireing from the datum line out to 400 meters and adjusted the 2 MG to 400 meters harmonised with it. Then adjusted the Revi graticule to account for the drop to 100 meters. The pilots learned how to use the graticule in gunnery school to determine range and ballistic drop.

If you want to get a feel for gunnery with the ballistics set closer to the manuals. Set all of your 109 and Yak and P39 motorkanone to 150yds off line and see how it works to shoot at things. That will be closer to the authenticity HTC seems to want to put into most of the wheapons systems in the game but the front page only says "High fidelity flight simulation". Not technicaly accurate wheapons system....

[trap78]

posted by bustr:

In the 109 seriese the Revi graticule was adjusted to a point at 100 meters that would corrispond to an endpoint at 400m describing a point on a level cross line to which the motorkanone rounds idealy would impact.

I just can't seem to wrap my brain around this bustr. Does it mean that the trajectory of the 20mm cannon round crosses the line of sight through the pipper of the Revi at 100 and 400 meters?

[bustr]

Jack the rear end of the 109 up so the engine/motorkanone 0-datum line is level and the wings are level. Place a board at 100 meters in front of the 109 about 8 feet tall wingspan wide with a horizontal line across it at the same hight as the 0-datum line. Fire your guns. You should roughly get the following patterns.

Gun Patterns Based on Engine/Motorkanone 0-datum line.

109F
MG151/20 @ 100M - 8cm below 0-datum
Rumpfh MG @ 100M - 13.5cm above 0-datum cross at 400m

109G6/U4
MK108 @ 100m - 19cm below 0-datum
MG131 @ 100m - 4cm below 0-datum cross at 400m
MG151/20 gondola @ 100m - 60cm below 0-datum cross at 300m

Reflexvisier H adjustement at 100 meters.

MG151/20 7.5cm above 0-datum
MK108 29cm below 0-datum.

You use the H adjustment screw to raise the graticule center to see over the nose to a zero at 100 meters. Then you use the lower stadia marks on the vertical cross hair to fire past 200 meters.

FW's the Reflexvisier line of sight was level from the center of the graticule to infinity. The MG were set to drop into the line at 400M and the MG151/20 at 550m. The MG convergence was to never cross the guns. The root MG151/20 at 600M and the outer MG151/20 at 400m. I beleive setting that up is called harmonizing the guns.

I think our convegence and target mode for all of the aircraft in AH works like the way the FW's were setup. We lob rounds over the level to infinity graticule line to drop rounds into a target level with our graticule line at the convergence range we choose from the hanger. The motorkanone had a fixed convergence that never touched level after the round left the barrel. MG and gondola were adjusted to follow the motorkanone trajectory out to 400 meters.

[moot]

[Tyrannis]

(Image removed from quote.)

lol whats with the cop? did the other guy park his 109 in a handicap zone or something?

[nrshida]

He's overseeing the forensics guy dusting for prints while they investigate the recent spate of engine thefts.

[pervert]

He's overseeing the forensics guy dusting for prints while they investigate the recent spate of engine thefts.

 

[Charge]

The pics should be pretty much selfexplanatory at this stage.

-C+

[trap78]

from bustr:

Jack the rear end of the 109 up so the engine/motorkanone 0-datum line is level and the wings are level. Place a board at 100 meters in front of the 109 about 8 feet tall wingspan wide with a horizontal line across it at the same hight as the 0-datum line. Fire your guns. You should roughly get the following patterns.

Gun Patterns Based on Engine/Motorkanone 0-datum line.

109F
MG151/20 @ 100M - 8cm below 0-datum
Rumpfh MG @ 100M - 13.5cm above 0-datum cross at 400m

109G6/U4
MK108 @ 100m - 19cm below 0-datum
MG131 @ 100m - 4cm below 0-datum cross at 400m
MG151/20 gondola @ 100m - 60cm below 0-datum cross at 300m

Reflexvisier H adjustement at 100 meters.

MG151/20 7.5cm above 0-datum
MK108 29cm below 0-datum.

You use the H adjustment screw to raise the graticule center to see over the nose to a zero at 100 meters. Then you use the lower stadia marks on the vertical cross hair to fire past 200 meters.

FW's the Reflexvisier line of sight was level from the center of the graticule to infinity. The MG were set to drop into the line at 400M and the MG151/20 at 550m. The MG convergence was to never cross the guns. The root MG151/20 at 600M and the outer MG151/20 at 400m. I beleive setting that up is called harmonizing the guns.

I think our convegence and target mode for all of the aircraft in AH works like the way the FW's were setup. We lob rounds over the level to infinity graticule line to drop rounds into a target level with our graticule line at the convergence range we choose from the hanger. The motorkanone had a fixed convergence that never touched level after the round left the barrel. MG and gondola were adjusted to follow the motorkanone trajectory out to 400 meters.

Does this mean yes the MG151 trajectory crosses the pilots line of sight through the pipper at 100 and 400 meters or no it does not?

[bustr]

No disrepect to HTC and I will gladly eat CROW with sand on it if I am wrong.

Charge I beleive HTC is using the method of your FW diagrams as the one size fits all convergence and gunnery model for the aircraft with fixed mounted forward firing guns to simplify gunnery as a key game process. But one would think 109 fans in the game would appreciate any amount of realism to support their image as having to work harder than the rest of the community to become better than them in the 109.

Consider what this means with the Ta152. Revi line of sight level to infinity won't work like on the FW A-D. MG151/20 set to drop off with the MK108 to pattern at 400 meters 12 feet down. Considering the line of sight over the nose is worse than the 109's, the H adjustment distance is probably performed at 50 meters and the lower stadia marks on the graticule become very important. None of the Ta152 manuals I have appear to have armerors diagrams for gunnery. I'll have to look again to see if they at least talk about setting the Revi H for zero.

If you pull the motorkanone and twin MG on any 109 back to 150 offline 20mm or 30mm birds you will find 200-250 yards is about your best range for getting rounds on a target with a 30 foot wingspan. Bombers out to about 400-600 yards. But, then that would be consistant with operational ranges in some of the after action reports. Didn't Galland complain with the 109F that loosing the wing guns made gunnery something only an Expert would be proficient at? Then he chose to keep his as a feild modification.

I was reading this weekend that the T9 37mm in the P39 had to be mounted parallel and close to the drive shaft because of the force of the recoil. Think thats why the N3 in the P39 had stadia marks below the dot? Wonder how many feet that 37mm drops at 400 meters?

ON the FW convergence diagram:

Yes the line of sight for the Revi graticule was level to infinity. The MG151/20 in the diagram arch up to the line of sight at about 120 and 135 meters per the diagram data spec and pass over it staying that way untill 550 meters. The MG131 stay above the sight line for almost their whole travel distancee to 400 meters. Your effective convergence for all 3 guns is about 250 meters 20 inches above Revi sight line with a 2 meter spread. 250 meters seems to be the effective fighter to fighter combat distance. 400-550 meters was for bombers.

[Charge]

In 109 the cannon shoots straight at the center of the main lines in targeting board as the cross suggests and the drop is 11cm at 100 meters as the black spot suggests. The sight's assembly height is 74,5 cm and in actually points down to height of 5cm in 100 meters. That means that the use of stadia marks are up to pilot's discretion but he knows that the cannon shoots to the center of the reticle at around 140 meters where the Hx is roughly the same for both the cannon and for Revi, and the second crossing point is somewhere around 400-500 meters due to ballistic arching. Between those distances he can use the stadia marks above the center of the reticle to estimate how high the rounds fly before arching down again. Beyond the second convergence point at 400-500m he can again use the lower stadia marks to estimate the drop.

Ta uses the same method as the 109 because of the center cannon which is not adjustable. The 190 has more freedom to adjustments and it uses the Revi line of sight as a reference and all the weapons can be adjusted to match that.

I haven't noticed how it is done in AH though. Bustr, do you mean that in AH the cannon shell, whether it is 20 or 30mm does not cross the sight line twice if it is "converged" to 100 or 400 yards? Because in both cases it should.

-C+

PS. The picture of the periscope that we saw earlier is used to point the cannon to center of the targeting board and with adjustable guns it can be used to optically set the hitting point to the right point in targeting board, however, it was preferred to check the calibration with live ammo as the optical system was not very accurate.