Bf 109 K-4 Kills? Anything Exceptional?

[Juha]

Hello HoHun

Quote:" At ranges out to 250 m, gravity drop hardly matters anyway."

I don't have info on gravity drop of MK108 (mv 505m/s for Minen) but the gravity drop for MG151/20 (mv 800m/s for Minen) was 100cm at 280m. IMHO that of MK108 should be larger.

Quote:" Nevertheless, the typical kill ranges were below "true" 250 m, not "perceived" 250 m."

Now IMHO the typical firing ranges is at least as interesting as the typical kill ranges, maybe even more so because it's entirely possible that most burst fired in dogfight missed and it's at least as interesting to know why a burst miss as why it hit. And higher mv usually meant flatter flight path and shorter flying time, both of which tended to lessen the effects of errors in sighting (for ex. in estimated range and lead and maybe even lesser extent errors in flying (for ex. skid and slip).

I agree that nose armament has inherent advantages vs wing armament, especially because dispersion is much less dependent on range.

Juha

 

[Njaco]

not to mention targeting.

 

[Maximowitz]

Slightly off topic, after researcking K-4 use by JG 53 I note that unit insignia was retained on the Eastern Front but not on the Western. Is there any particular reason for this?

 

[HoHun]

Hi Juha,

>I don't have info on gravity drop of MK108 (mv 505m/s for Minen)

According to the Bf 109G-6 harmonization chart, about 1.3 m at 250 m. However, as the sightline of the gun was depressed, the procectiles actually strike about 55 cm above the aim point. Roger on the strike point displacement in banked flight. Inversed flight would be even worse

>Now IMHO the typical firing ranges is at least as interesting as the typical kill ranges, maybe even more so because it's entirely possible that most burst fired in dogfight missed and it's at least as interesting to know why a burst miss as why it hit.

Hm, I'd think it's most interesting to know the range at which there is a worthwhile probablity of a kill, especially when we're discussing the possiblity of multiple kill missions In my opinion, the harmonization distances were typical for the expected worthwhile fighting range - there is some effectiveness remaining beyond conversion range so that range underestimation doesn't result in completely hopeless shots, but the "sweet spot" is clearly inside harmonization range.

>And higher mv usually meant flatter flight path and shorter flying time, both of which tended to lessen the effects of errors in sighting

Undoubtly true, but there is a limit to the benefit. If you double the muzzle velocity, you can reach out to twice the distance with the same flight-time dependend problems as before ... but being twice as far away, the target will be only a quarter of the effective size (as seen through the gunsight). As a high-velocity gun tends to lose firepower compared to a low velocity gun of similar mass and size - sacrificing either cyclic rate or calibre for muzzle velocity -, it's really more a question of what trade-off you prefer.

In my opinion, sacrificing muzzle velocity makes sense because the resulting firepower makes it possible to score decisively even in snapshots, which can be achieved by criss-crossing the enemy's path instead of tracking him. Comparing a 600 m/s gun with a 900 m/s gun, closing in to 120 m instead of 180 m will give the same firing solution, but a target that is more than twice as large in the gunsight. The time to collision (and accordingly the possible firing time) is 2/3 of that for the high-velocity gun ... but with a more powerful gun and a target more than twice as large effectively, this is a good trade-off.

Additionally, criss-crossing instead of tracking is a tactical method that conserves energy and avoids flying a predictable path, and makes it possible to keep up "out-of-plane" manoeuvring. Of course, you can also do that with a lower-firepower weapon, but that means you're committed to firing opportunities with low chances for a decisive hit on the enemy. If you can afford to take your time in killing the opposing aircraft, this is no problem, but usually it's much better to knock down the enemy quickly before something unexpected happens than to hang around for long, even if it looks like you'll win in the long run. I think Shaw talks of the danger of being jumped by "wildcard bandits", conveying the unpredictable nature of the danger quite well

So a high-firepower, low-velocity gun actually enables the pilot to maneuvre in a way that would not be particularly promising with a different type of battery, and accordingly I consider the MK 108 an excellent gun for dogfighting.

However, I'd say the optimum fighter armament probably would be closer to the battery of the Ta 152H than to that of the Me 109K - there are situations when a higher muzzle velocity is desirable, like a tailchase of a fast bandits, or when you have an opportunity for a long-range deflection shot, and the wing-root 20 mm cannon of the Ta 152 really augment the MK 108 nose cannon very nicely.

>I agree that nose armament has inherent advantages vs wing armament, especially because dispersion is much less dependent on range.

Absolutely, and it's not an exclusive Luftwaffe preference either ... in the USAAF, the P-38 battery with its nose guns was highly regarded by the pilots, too.

Regards,

Henning (HoHun)

 

[davparlr]

The Me 109K-4 simply was an evolution of the general-purpose fighter Me 109G-6 with a stronger engine and some aerodynamic improvements.

My resource show that the K was also quite a bit lighter, empty weight of a K-6 was 5161 lbs, than the G-6, empty weight of 6050, almost 900 lbs lighter. Like the P-51H, it was quite a hotrod.

 

[Chocks away!]

It's obvious to me that the 30 mm cannon on the Bf-109 was a way to give it anti-bomber cababilities without weighing it down with gondolas. Why don't we see the Bf-109 G-10/14/6/AS and K with wing gondolas in early 1945?

It's obvious they were too much of a compromise in agility.

 

[Erich]

actually you do.........

in combat with US heavy bombers as well as the NF versions doing up ground attack duties against the Allies/Soviets

and Maxi, Landt and his unit fought on the western front, the Pik-AS Geschwader emblem was removed from all 109's whether on Ost or West front, the black Rumpfband was worn as a Reich defense ID during 44-45 by JG 53 and yes there are pics of Landt and his K-4, he survived the war but not sure what happened to him.........

E

 

[kool kitty89]

My resource show that the K was also quite a bit lighter, empty weight of a K-6 was 5161 lbs, than the G-6, empty weight of 6050, almost 900 lbs lighter. Like the P-51H, it was quite a hotrod.

How does that compare to the Weight of the G-10 and G-14?


Still, that's pretty impressive, considering the K-6 had 1x additional MK 108 inside each wing.

 

[Juha]

Hello HoHun

Quote:"According to the Bf 109G-6 harmonization chart, about 1.3 m at 250 m."

Thanks a lot.

Quote:" In my opinion, the harmonization distances were typical for the expected worthwhile fighting range - there is some effectiveness remaining beyond conversion range so that range underestimation doesn't result in completely hopeless shots, but the "sweet spot" is clearly inside harmonization range."

More or less I agree but I'd put it a bit more mildly, the harmonization distances were usually reasonable and effective range. FC began WWII with 400y harmonization, that would probably be the expected worthwhile fighting range, but fairly soon some sqns dropped the harmonization distance to 350 or 250y, in March 40 Dowding decided to change the harmonization distance to 250y. And Finnish AF used 150m as the harmonization distance. FC test early in the war showed that when pilots were ordered to fire at target at300y actual distances were 800-1200y, so pilots were advised to halve their range estimates and double their estimate of the lead and also advised to open fire as close as possible.

Quote:" Undoubtly true, but there is a limit to the benefit. If you double the muzzle velocity, you can reach out to twice the distance with the same flight-time dependend problems as before ... but being twice as far away, the target will be only a quarter of the effective size (as seen through the gunsight)."

Absolutely true but I was thinking easing the sighting problems not increasing firing range. It always preferable to fire from close distance, it solved most problems.

Quote:" As a high-velocity gun tends to lose firepower compared to a low velocity gun of similar mass and size - sacrificing either cyclic rate or calibre for muzzle velocity -, it's really more a question of what trade-off you prefer."

Absolutely true! IMHO maybe the best fighter gun was Hispano Mk V, clearly higher mv and higher rof than MK 108 but clearly less effective ammo with 2/3 weight. But it's matter of opinion. A bit large dispersion possible with tvo Mk Vs vs one MK 108 (weapon weight 84kg vs 60kg) would probably be preferable for average pilot, crack shots being rare. But it's entirely how one weighted different relevant factors.

Quote:"do that with a lower-firepower weapon, but that means you're committed to firing opportunities with low chances for a decisive hit on the enemy"

True but 2-3 20mm hits probably at least remove enemy fighter from that fight and increased possibility that you or some other can get telling burst at the enemy later in the fight.

Quote:"In my opinion, sacrificing muzzle velocity makes sense because the resulting firepower makes it possible to score decisively even in snapshots, which can be achieved by criss-crossing the enemy's path instead of tracking him."

But it makes hitting with those snap shots harder. Of course most of pilots would not hit anyway.

Juha

 

[kool kitty89]

The best gun choice would be a compromise between velocity, cyclic weight, and caliber. (in addition to the weight and size of the gun, plus characteristics of the gun's operating mechanism, the, feed mechanism, and reliability)


Here's a good article concerning the optimum armament: IDEAL WW2 FIGHTER ARMAMENT

More here: BOOKS BY ANTHONY G WILLIAMS
A particularly interesting article being:ANOTHER MISSED OPPORTUNITY: THE OERLIKON FFL CANNON (something I had wondered about myself before finding these articles)

 

[kool kitty89]

Empty weights of the G-10 and G14 apear to be to be ~5,066 lbs (2,300 kg).

 

[Kurfürst]

My resource show that the K was also quite a bit lighter, empty weight of a K-6 was 5161 lbs, than the G-6, empty weight of 6050, almost 900 lbs lighter. Like the P-51H, it was quite a hotrod.

Nah, this has been discussed a couple of times. The 109K wasn't a lightened 109 airframe. It was a strealined, but slightly heavier airframe.

Note: the Ladeplan chart is for a G-6/trop, it was something like 50kg heavier than the normal ones w/o tropical equipment.

 

[Maximowitz]

Nice one Kurfurst. Are there any accounts by pilots as to its handling and flight characteristics in comparison with previous models?

 

[HoHun]

Hi Juha,

>More or less I agree but I'd put it a bit more mildly, the harmonization distances were usually reasonable and effective range.

Not a bad way to put it Neil Stirling once posted excerpts from a RAF gun camera analysis report showing that 52% of the kills were achieved at less than 200 yards range, 34% from 200 to 400 yards, and only 14% at more than 400 yards. (And slightly more than 50% of all these kills were achieved with gyro gunsights ...)

It's not like the guns just stopped to function at long range, effectiveness just kept decreasing smoothly with increasing range.

>FC test early in the war showed that when pilots were ordered to fire at target at300y actual distances were 800-1200y, so pilots were advised to halve their range estimates and double their estimate of the lead and also advised to open fire as close as possible.

Hm, Fighter Command training doctrine seems to have been rather "rational", including setting the sight to the target wingspan, estimating the angle-off and the target speed, and calculating the required lead. The problem with this method is that it is slow, while air-combat is fast paced. I'm convinced a "flash card" approach (as developed during WW2 for aircraft recognition training) would have been more useful. Unfortunately, I don't know what doctrine the Luftwaffe used, but I noticed Reschke made mention of a card game (for solitary play) distributed by the Luftwaffe that was supposed to train the pilots in deflection shooting. It would be interesting to know if this worked on the "flash card" principle.

(Luftwaffe aircraft recognition seems to have relied on learning characteristic features for every plane, and I don't think they ever adopted the flash card method there. On the other hand, I've read that Luftwaffe "Morse" key operators were trained with a "high speed" approach that could be considered the acoustic equivalent of the flash card approach To this day, "to morse" is a verb in German, by the way.)

>Absolutely true but I was thinking easing the sighting problems not increasing firing range.

Agreed, I just mean to highlight that as always in aviation, there is a trade-off involved. In the case of the MK 108, the higher firepower at short range out-performs the accuracy gain one might have from a higher muzzle velocity.

>IMHO maybe the best fighter gun was Hispano Mk V, clearly higher mv and higher rof than MK 108 but clearly less effective ammo with 2/3 weight. But it's matter of opinion. A bit large dispersion possible with tvo Mk Vs vs one MK 108 (weapon weight 84kg vs 60kg) would probably be preferable for average pilot, crack shots being rare.

The Hispano V certainly is a good all-around cannon, and I agree that it is to preferred over the Hispano II because it gained some firepower over the older gun at the expense of a bit of muzzle velocity.

However, when comparing fighter gun installations, the ammunition supply should not be neglected. Here are some batteries with equal ammunition and roughly comparable firepower (based on total muzzle energy):

1x MK 108 - 87 rpg - 111 kg - 221% firepower
2x Hispano V - 212 rpg - 188 kg - 109% firepower
8x ,50 Browning M2 - 250 rpg - 452 kg - 100% firepower
25x Browning ,303 - 399 rpg - 549 kg - 96% firepower

Starting with the smallest calibre, the 25-barrel rifle-calibre machine gun battery obviously will be very hard to install in a single-seat fighter for lack of space The eight heavy machine guns are realistically possible, but comparing the complete installation to the twin Hispano battery, it's obvious that heavy machine guns come with a hefty weight penalty for the limited firepower they offer. The MK 108 not only is lighter yet than the Hispano cannon, but it additionally doubles the firepower. It can also be installed in the nose of a conventional single-engine fighter (if the engine is designed for it), while the Hispano V is unfit for synchronization so that you either have to restrict yourself to one engine cannon, reducing firepower, or mount the pair of them outside the propeller disk, with the ill effects we already discussed.

So let's change the battery to 3 Hispano (one engine cannon, two wing cannon - the Merlin didn't allow this, but the Hispano-Suiza did), comparing it to the MK 108/MG 151/20 combined battery I mentioned:

3x Hispano V - 141 rpg - 230 kg - 163% firepower

1x MK 108 - 43 rpg - 85 kg - 221% firepower
2x MG 151/20 - 105 rpg - 128 kg - 112% firepower
Total: 213 kg - 333% firepower

So I get about twice the firepower for the Ta 152 cannon setup compared to the triple Hispano V setup, at roughly equal weight if I use comparable ammunition loads. The Ta 152 setup would lose some firepower at longer ranges, but as the RAF report quoted above shows, long range fire was the excepton rather than the norm. Additionally, the MG 151/20 can be synchronized, and the wing-root position of the Ta 152's cannon has the well-known ballistic advantages over the wing-gun position necessary for two of the three Hispanos we're considering.

(Grr, now I notice that I probably should have used the data for the somewhat more powerful MX ammunition introduced late in the war for comparison to the late-war Hispano V. Well, I'm not going to re-do the calculations ... the picture is clear enough after all

>True but 2-3 20mm hits probably at least remove enemy fighter from that fight

Sometimes maybe, but taking into account that the Luftwaffe considered an average of 6 x 20 mm required to destroy a fighter aircraft, I don't think it's realistic to expect that as the normal result.

>>"In my opinion, sacrificing muzzle velocity makes sense because the resulting firepower makes it possible to score decisively even in snapshots, which can be achieved by criss-crossing the enemy's path instead of tracking him."

>But it makes hitting with those snap shots harder.

The lower muzzle velocity makes it harder to achieve nominal hits, but at the same time the massive firepower of the MK 108 makes it much easier to achieve decisive hits. It is a trade-off ... you sacrifice hit probability to increase the probability of a kill.

It also means that snap shots are a worthwhile tactic at all, as with a lower-firepower weapon, you might be forced to go for a tracking shot, which means that have to commit yourself to trade energy for angles - which can be a rather dangerous course, especially if you're up against multiple bandits.

Regards,

Henning (HoHun)

 

[kool kitty89]

HoHun would you agree thogh that a bit more compromise of RoF and gun weight for a higher velocity would be more desireable. (the MK 108 being a bit extreme)

Say a gun weighing 70 kg firing the same projectile at ~780 m/s with a cyclic rate of 500 rpm. (incedentally very similar to the performance of the IJN 30 mm Type 5)

 

[HoHun]

Hi Koolkitty,

>Here's a good article concerning the optimum armament: IDEAL WW2 FIGHTER ARMAMENT

I've in the past discussed this with Tony, and I'm afraid that I've been unable to successfully convey to him the concept of the fighter pilot being able to adapt the firing range to suit his weaponry, which has considerable impact on the thought excercise.

Matching trajectories for killing ranges that in 86% of the cases did not exceed 366 m is really an unnecessary luxury as even differing trajectories yield small patterns at such short ranges.

Tony's assessment of cannon in that (oldish) article also still relies on his slightly inaccurate rule of thumb for explosive ammunition that underestimates the power of slow high-explosive projectiles.

Though this might be surprising after my critical words above, but I totally agree with Tony's conclusion that for a conventional single-engined WW2 fighter, two synchronized 20 mm wing-root cannon combined with a 30 mm engine cannon is the optimum historically realistical armament

Despite my detail critique, I'd say Tony has hit the nail right on the head with regard to the cornerstone parameters

Regards,

Henning (HoHun)

 

[HoHun]

Hi Koolkitty,

>HoHun would you agree thogh that a bit more compromise of RoF and gun weight for a higher velocity would be more desireable. (the MK 108 being a bit extreme)

>Say a gun weighing 70 kg firing the same projectile at ~780 m/s with a cyclic rate of 500 rpm. (incedentally very similar to the performance of the IJN 30 mm Type 5)

Yes, I'd agree. The parameters you suggest look quite attractive to me. I'd even settle for less than 780 m/s

In the Ta 152H battery, the low muzzle velocity of the MK 108 doesn't really worry me as the 20 mm cannon can be used for the longer-ranged shots, but in the Me 109 installation where the only supplementary guns are machine guns, I'd be ready to sacrifice some firepower for greater muzzle velocity for greater tactical flexiblity.

I wouldn't change the cannon all the way to the high-velocity, low rate-of-fire MK 103 though - that would be the opposite extreme

Regards,

Henning (HoHun)

 

[Juha]

Hello HoHun
Quote:"Additionally, the MG 151/20 can be synchronized, and the wing-root position of the Ta 152's cannon has the well-known ballistic advantages over the wing-gun position necessary for two of the three Hispanos we're considering."

I agree and IMHO the 2 wingroot MG 151/20s of Fw 190/Ta152 were optimically placed giving a bit dispersion but not too much and a way that was not too much influenced by range. Only problem was that syncronisation reduced somewhat rof but IMHO that was acceptable. What I don't like in Ta 152 armament was the different ballistics of MK 108 and MG 151/20.

Quote:"Sometimes maybe, but taking into account that the Luftwaffe considered an average of 6 x 20 mm required to destroy a fighter aircraft, I don't think it's realistic to expect that as the normal result."

What I was trying to say was that 2-3 20mm hits were normally enough to damage fighter so much that its pilots would try disengage immidiately and leave the fight. At least even agressive Finnish pilots seemed to have done that in that situation.

IMHO our difference is in essence that we weight differently which is more important
higher probability to achieve at least so damaging hits that they forced enemy to disengage
vs
lower probability to achieve hits but hits would be with high probability destructive.

Juha

 

[Amsel]

The MG 151/20 and Mk103 mix seems to be the best all round variant in my opinion.

 

[kool kitty89]

The differences in ballistics of the Mk 103 and the MG 151/20 are about as big as those of the MG 151/20 and MK 108. And the increased weight of the MK 103 would adversely impact performance. (and the rate of fire is really fairly low to be very useful, and I believe ammo supply was somewhat less as well)