BF-109 Canons

[horrido]

Hello All

I have a question

The BF109E had two 20mm canons in the wings. Why was this discontinued on later versions?

I know you could add cannons to the wings in gunpods in the Gustav, but why were they not integrated into the wing like in the Emil version?
The wing was rounded-out, but was this such a big change that it made it impossible to keep the 20mm's in the wings?

Thanx

[RMAllnutt]

I have read that the internal wing armaments were deleted after the emil due to weakness in the wing design. I do not know for sure if this is true. I seem to recall that there were some versions of latter 109's which had provisions for special gun pods attached to the undersides of the wings as an alternate solution.

There is an interesting time-line of '109 development on this page...

http://www.bf109.com/evolution.html

Hope you find this useful.

Cheers,
Richard

[Bf109K4]

The Bf109 had a history of high wing loading that dogged the aircraft throughout it's life. This restricted its manouverability and made dog fights a sweaty, stressful and muscular past-time. This created the idea that the 109 was basically a fighter that could only get in for high speed attacks, hit hard and quick and then use speed to get away.

When the Bf109F appeared it's first incarnations were armed with a 15mm Cannon firing through the spinner and two 7.9mm machine guns firing through the prop on top of the engine cowling. The wing seems to have had a partial redesign which ruled out internal guns or cannons. By stages this increased to a 20mm Cannon and two 7.9mm machine guns then a 20mm Cannon and 13mm machine guns. 30mm Cannon were also experimented with but for whatever reason in the evolution of the 30mm problems arose and the 20mm was rekoned to be that much better. All of these waepons were centred around the engine and thus eliminated high wing loads.

I believe that the idea of stripping the two 20mm wing cannons out as really to allow the Bf109F to compete with fighters such as the Mk V Spitfire in dog fight situations as it had been deemed that the Bf109E suffered in tight twisting encounters. The reduced arms were deemed to be enough to destroy fighter aircraft and medium bombers.

However no sooner that the 109F was out to units in N. Europe the appearence of the heavy bomber in the form of B-17's and B-24's nessesitated an increase in weapons and weapons load. It faired a little better in N.Africa against the Desert Air Force although a lot of other factors were in it's favour too.

To combat the heavy bombers various combinations of weaponary start to appear, apart from 20mm or 30mm Cannon firing through the spinner we see 15mm and then 20mm extending eventually to 30mm Cannon in underwing gondolas. The 13mm machine gun becomes standard on top of the cowling. Later various rockets and then timed fuse bombs appear as well.

Just out of interest, the Bf109F is reckoned to be one of the highlights of the various marques of 109 produced but it's immediate sucessor the Bf109G-0, Bf09G-1 and Bf109G-2 were dogged with engine fires and cockpits that filled with smoke. Indeed cockpit smoke and a forced bail out was the cause of Hans Jockheim Marseilles death in a Bf109G-2 and Heinz Knocke describes in his book "I Flew for The Fhurer" the same sad reason for one of his collegues deaths in a non combat situation.

High wing loading was the cause of many crashes both then and it would appear more recently too. Restorations of Bf109G-2's seem to have also inherited the marques wartime problems. Heinz Knocke describes take-off and landing as having to carefully watch the left (port) wing which will immediately dip if you take off at the suggested Vr. He describes holding the aircraft down for another 10Knots or so. The leading edge slats also "snatch" at Vr speeds. The same applies in landing with higher than suggsted speeds.

It seems that this was never resolved even in the final Bf109G-14 and Bf109K-4 consolodations of the fighter. However as Erich Haartmann proved in 352 kills a seasoned veteran in an aircraft he knows has a lot going for him, high wing loading or not.

[Forgotten Field]

We need to ban this guy from the WIX- too much technical knowledge which seems to be verifiable independently. We cannot have that here.

I am joking- that was a very interesting commentary on an aircraft I know little about. Thanks much for posting the details!

[mrhenniger]

...that was a very interesting commentary on an aircraft I know little about. Thanks much for posting the details!

I agree. Welcome to WIX!

Mike

[Bf109K4]

Even I (whoever I am, if you know please tell matron!?) have a question and I'm still on the steepest learning curve ever!

What makes a Machine Gun a Machine Gun and a Cannon a Cannon. One of the difficulties I've had with some of the technical stuff on not only the Bf109 but almost every other German Fighter and Heavy Fighter is differentiating from Machine Gun and Cannon.

This mostly manifests itself with the 15mm Machine Gun or is it Cannon or were there both. I think the mix up has come in a lot of early translations and generally misleading information seen in the field. Take for example the Bf109K4. I have seen descriptions of the fighter having a 30mm Cannon through the spinner but either two 13mm or "15mm" Machine Guns.

However earlier descriptions of the 15mm in the F series describe it as a Cannon. Further some of these "Cannon" found their way onto underwing gondolas. What about field modifications? Can anyone shed light on this?

Another question concerns the Heinkel 219 UHL (Owl). The first edition of Purnells History of The Second World war describes it's armanent as "six 30mm Cannons in the belly/bomb bay, four 20mm Cannons on the starboard wing and two 20mm Cannons on the port wing giving 180lbs of shot in a one second burst. I have seen other descriptions and variations in the gun line up but this by far and away is the heaviest. It begs the question, was this aircraft the heaviest armed of the war.

It also asks the question that although it was a night fighter in the main what could it do in seasoned hands. Marseilles was reckoned to be able to have nailed you in as little as four rounds. Some opinion suggests that 6 x 30mm Cannon rounds, well placed, would bring a B17 down, so a one second burst from an He219........the mind boggles!

Nurse is calling, cold bath again, see you!

[lmritger]

With regards to Hans Joachim's accident, this was traced to overheating of the larger DB605 engine, which led to a failure of the reduction gear. The 605 had a number of consistent issues; one of the bigger ones was oil aeration which interfered with engine lubrication, leading to overheating or locking up the engine (not a good thing to happen while airborne!). The 605 also introduced a twin spark plug head (the 601 had one plug per cylinder), and the plugs burned out on a depressingly regular basis; this led to the inclusion of the small semicircular scoops on the forward cowling, which also helped a bit with engine overheating.

The deletion of the wing cannons from the F onwards can be summed up in two words: roll rate. Reduce the amount of weight outboard, and you increase the roll rate of the aircraft. The 109 was actually quite manouverable when not laden with outboard rockets or gondolas; when the R6 "gunboat" field conversion kit was added, the manouverability of the aircraft was correspondingly reduced.

Lynn

[mike furline]

If I understand your machine gun / cannon question correctly, a "machine gun" fires a non-explosive bullet and a "cannon" fires an explosive shell.

The largest "machine gun" used was the MG 131 which was 13mm.

The MG 151/15
In 1935 the MG 151 was developed by Mauser. This weapon got a caliber of 15 mm. The whole gun was 1960 mm long and weighted 42,7 kg. Here the cartride had a weight of 190 g and the bullet weighted 72 g.
This machine cannon was able to spit 700 rounds per minute, which reached a muzzle speed of 1040 meters per second. The cartridges were transported by a metal belt.
The "Bf 109 F-2" got such a MG 151/15 in the bow, shooting through the hollow propeller axis. Because the shooting results were not satisfying, the MG 151/15 was replaced by the MG 151/20.

The 151/20
To increase the power of MG 151, Mauser developed 1937 a design with 20 mm caliber. This re-designed Weapon was with it´s 42,5 kg a little lighter and with 1710 mm also a little shorter as the MG 151/15. The bullets left the cannons barrel with 790 meters per second, at a cadence of 750 rounds per minute.
The weapon was "feeded" by an ammunition belt. One of these cartridges had a weight of 220 g, the projectile alone has a weight of 115 g.



Regards,
Mike

[marine air]

Thanks for explaining that about the armament. I always had guessed the "gunboat pods" were an attempt to increase "knock down power against the bombers and also for ground attack. As for the wings, I believe Wily Messerschmitt had a long standing preference for keeping the wings light. That's why the landing gear attach points and fuel were in the fuselage. I think the 109 has a single spar wing like the Bf-108.
The light wings would not only give it a quicker roll rate but would make the aileron reversal much more effective. If you get a chance, go out in an airplane like a Piper Lance, or C-310, or anything that carries a lot of fuel, and try making a quick aileron turn and then snap opposite aileron . Try it with a full load and later when at minimum fuel.YOu will be amazed how much 100 gallons will make on the aileron's responsiveness. Fuel in the wing tip tanks really dogs it up.
As far as wing loading, The 109G and especially the Buchon, have a higher wing loading than the Yak-3 or even the P-47 Thunderbolt! It's in the range of a B-26 Marauder, if I remember correctly.
Regards,
Marine Air