samedi 12 mars 2016

The Messerschmitt Bf 109, Master of the sky in 1940... and after (revised 16 / 06 / 2016)

A fighter designed for high speed and easy air combat

The Messerschmitt Bf 109 fought restless from 1937 (in Spain) to 1945 in the Axis forces, and again until in the 50's in the hand of Israeli pilots (!).

Such a long operational life during three savage wars demonstrated an outstanding general conception.

When she made her first flight, in Spring of 1935, she was, by far, the most advanced of all fighter planes on the Earth. 
  • She used a sturdy, light, and all metal monocoque structure able to accept powerful engines.
  • The fuselage was designed to be perfectly fitted to the smallest possible section, allowing a very high top speed.
  • The cockpit canopy had the minimum size compatible with a good forward and lateral visibility.
  • The wings were fitted slats in the leading edge and flaps in the trailing edge for short landings.
  • The pilot seat had a slope of 17° to minimize the effects of blackout on her pilots during tight maneuvers.
  • The aircraft was conceived to be built quickly (7,500 h for the Emil and less than 5,000 h for the Gustav).

For these reasons, she remained the favored fighter of all German aces, as the top scoring one, Eric Hartmann, who downed 352 Allied planes (!) without any loss of teammate, without having be hit by any Allied fighter pilot. 

A fact which he shared with the top Allied ace during WW I, René Fonck.

During the German contest of 1936, the Messerschmitt 109 was well above all the other contenders.

She had a take off weight of 1,900 kg (without weapons nor ballasting).

With her Rolls-Royce Kestrel engine of 695 hp, her top speed was 473 kph at altitude with a good climbing speed (13.7 m/s), much better than those of her contenders.

Owing all her qualities, the 
Göring's RLM (Reich Luft Ministerium = Imperial Air Ministry) ordered her immediately as the standard fighter of the Luftwaffe.

Unfortunately for us, that order was very relevant... (one of the great problem of France's deciders who ordered the slow Morane-Saulnier 406 and not the - at least - 35 kph faster Nieuport 161).

The development of the Bf 109 was perfectly synchronized with the evolution of the threats

The empty weight increased as a logical consequence of even more powerful engines as, also, the need of more deadly weapons.

The B variant - used in Spain - was 300 kg heavier, translating just the fitting of the Junkers Jumo 210 engine (delivering 680 hp) and 2 machine guns (of riffle caliber).

The E1 variant, which opened WW II on the French front was 400 kg heavier than the previous B variant. 

So, this operational fighter weighted 2,660 kg for take off (the prototype of this variant "claimed" 2,540 kg, a behavior seen with numerous other fighter prototypes in the World). 

This over-weighting was the consequence of the fitting of the powerful Daimler-Benz DB 601 direct injection engine, whose weight induced a 50 kg ballast at the rear of the fuselage.

Nevertheless, the Bf 109 E (Emil) fighter became an especially well performing aircraft.

Following the sources, the top speed oscillated between 555 kph and 570 kph.    

This excellent German site give us the data of the prototype:
  • 500 kph @        0 m 
  • 510 kph @ 1,000 m 
  • 530 kph @ 2,000 m 
  • 540 kph @ 3,000 m 
  • 555 kph @ 4,000 m 
  • 570 kph @ 5,000 m 
  • 565 kph @ 6,000 m 
  • 560 kph @ 7,000 m 
Following the weapons fitted, the take off weight, the camouflage painting, the top speed may be reduced up to 20 kph (as for all other fighters in the World).

The total range was 660 km.

Nevertheless, this top speed so widely published was available only during 5 minutes, owing the risk of overheating. 

The normal top speed was, in fact, 530 kph, with the radiator flaps open...

A today - impressive - picture of a Bf 109 E3, with radiator flaps open

The climbing times were : 
  • 4,000 m in     5',
  • 5,000 m in     6' 30",
  • 8,000 m in   13' 30". 
These performances were excellent. 

In the Battle of France

During the Battle of France, in May and June 1940, the qualities of the Emil were enhanced by:
  • The tactic dispositions in pairs (Rotte),
  • The use of the excellent Freya radars,
  • The overwhelming strength of 1,000 fighters against about 580 French ones and less than 200 British ones (except for Dunkirk), the few Belgian and Dutch fighters having disappeared very quickly.  
  • Moreover, the German pilots were able to do 4 sorties every days, when the French pilots were doing, at best, 2 sorties, even if this information must be counterbalanced by the longer time they flew, especially with the Dewoitine 520 and the Curtiss P 36 (but not with the Bloch 152 which had an endurance of only 600 km). 
One of the assets of the Bf 109 E was her very small frontal section, which forbid many gunners to engage her just in time, because they overestimated the distance where are the German fighters.

Nevertheless, the Bf 109 experienced some problems, especially when they failed to surprise their Allied opponents. 

Facing a great diversity of foes

The various types of Allied fighters they faced were conceived following very different schools of thinking. 

So, the German pilots - not very smart in aircraft recognition - might have been surprised when they attacked fighters behaving in a different way that they expected. 

For example, the British Hurricane was optimized for the tightest turn at low speed. Her real top speed (490 kph), fair to chase and destroy the German bombers, was a bit too slow to match evenly with the Bf 109 E.

The Morane-Saulnier 406 was even much slower - in both horizontal and vertical maneuvers - but she was also more nimble and may compensate her weak top speed when flying in semi-dive (better roll speed).

The Fokker D XXI, with similar top speed than the MS 406, was even more nimble and climbed very better than the Morane.

Being 50 kph faster then the MS 406 and the Fokker D XXI, the Bloch 152 was also clearly more maneuverable than the Bf 109 at low altitude. 

She had always a better roll rate and can climb more easily in tight right hand turn (CEAM report 1940). She had also a decisive advantage in fire power.

The Dewoitine 520 was very good at high speed and, also, at altitudes higher than 4,500 m.

Contrarily to the French report of the CEAM, the pilots who were accustomed to the D. 520 demonstrated she turn more easily than the Bf 109.

Unexpectedly, the German pilots identified often the Dewoitine fighter as a MS 406, a fatal error!  

One may not forget that, during the Battle of France, all Bf 109 E were fitted with 1,050 hp DB 601 engines (at altitude). 

Only at the end of the Battle of Britain, some of them were fitted with 1,175 hp DB 601 engines, which entered service hurriedly owing the problems encountered in France

So, these Emil had a ~20 kph better top speed.

Nobody is perfect, but the shortcomings of the Emil were not from her own...

What were the weakness of the Messerschmitt 109 E fighter?

To know that, we need only to confront the Messerschmitt fighter to the missions she had failed to fulfill! 

The first failed mission of the Luftwaffe was the Battle of Britain, in which the Emil downed (I chose to add the written off fighters and the damaged fighters) more British single seat fighters (1,158) than themselves downed Bf 109 E (746).

This half-failure cannot be attributed to the Emil but to the high ranking deciders who forgot completely the war program written by their boss, Adolph Hitler, in his book Mein Kampf

The war against France was only the entry gate for the real game, a game aiming to conquer, at least, the West lands of USSR!

Obviously, everybody focused on the weak endurance (660 km) demonstrated by the Emil fighter, but exactly the same problem occurred for the Supermarine Spitfire.

Both were defensive fighters with a poor combat radius.

The supplementary tanks already existed in several countries as, e.g. in France, with the two wing tanks (2 x 150 liters) of the series Dewoitine 520 (even they were forbidden for use during a combat, when these tanks contained fuel).

The 180 days between the 1st January 1940 and the 1st July 1940 were sufficient to build at least thousands auxiliary tanks for the Emil.

When, effectively, such a jettisonable tank was fitted on the Bf 109 E7 variant, this happened very late, in the last part of the Battle of Britain.

One may attributed this to the too short sighting of the Luftwaffe deciders, not to the Bf 109 fighter designers.

The real weakness of the Bf 109 E: An armament devoid of punch

The weapons fitted on such a slim fighter were at problem since her very début.

The German deciders displayed the same wrong reasoning than other deciders in Europe.

Using the same riffle caliber machine guns, efficient against the 1,990 kg Bréguet XIV of mixed construction in 1918, was irrelevant against multi-engined all metal bombers weighting 12,000 kg!  

The British military deciders postulated also that eight such machine-guns firing during 2 seconds (!) was absolutely sufficient to down every opponent aircraft. 

They were, apparently, not aware of how long are two seconds during an aerial combat...

That explains, also, how the Captain Véniel (French Air Force), attacked by a dozen (?) of Bf 109 E, was able to down one of them and to return home safely with his Bloch 152 carrying 360 hits

Nevertheless, this pilot was absolutely critic about his own plane!

During the Battle of France, the Emil (mostly the E 1 variant) was fitted with 4 MG 17 machine guns (two free firing ones in the wings and two synchronized ones in the cowling).

These MG 17 had a relatively low muzzle velocity of 760 m/s.

In the later E3 variant (the one used during the Battle of France and, also, the most produced one with ~1,300 fighters), the wings mounted- machines-guns were replaced by Oerlikon cannons MG FF. 

This new weapon had a low muzzle velocity of only 580 m/s
Compared to the 880 m/s of the Hispano-Suiza HS 404 cannon, the ballistic capacities of the MG FF were clearly inferior, as their impact energy which was the half of the French one.

So, the Luftwaffe used lighter but enhanced explosive shells.

Nevertheless, if you add a short combat radius to "no decisive" weapons, the enemy aircrafts you are attacking had undoubtedly more chance to "survive".

The development of the Bf 109 was not always compatible with the tactical reality 

The following career of this excellent fighter began when Messerschmitt, at the end of the Winter, in 1941, delivered the brand new F variant (Friedrich).

The new fighter was literally transformed by a perfect aerodynamic cleaning affecting a lot of so-called "details". 

With a DB 601 N engine not much powerful than the one of the E 7 Emil, the Friedrich was 40 kph faster.

Bf 109 F - A perfect cleaning

The Daimler-Benz 601 N delivered about 1,200 hp in 1941

In the same time, the Friedrich received a new armament, rather similar to the one the French used, with a engine-mounted cannon. They tried such a layout very early, without success because the cannon seized very quickly.

After the occupation of France, the German engineers had all the needed time to understand how the French ones had used, so they can use of a moteur-cannon and two heavy machine-guns of 13 mm (replaced later by two 15 mm ones).

The F2 variant had a take off weight of 2,730 kg for defensive missions.

The top speed was better than 610 kph at 5,200 m and the climbing time for 8,000 m was 10 minutes.

The service ceiling exceeded 11,000 m.

The F4 variant appeared in 1942 with a more powerful DB 601 E delivering 1 350 hp.

So the top speed was 635 kph at 6,200 m.

The time for executing a 360 ° turn was ~20" instead of 25" for the Bf 109 Emil.

According to most involved airmen, the Friedrich variant was the best of all Bf 109 variants.

She was successfully used against fighters of United Kingdom and USSR from 1941 to 1942 which were all outclassed.

Game change

Unfortunately for Herr Hitler, at the end of 1942, the light Bf 109 F, facing the tough Boeing B 17 American bombers - which had a very heavy fire power - was totally inefficient.

The Bf 109 G (Gustav) variant was a wrong answer to this very good question. 

The German Air Staff re-used the kind of adaptation they used in early 1917 to eliminate the BéBé Nieuport menace : Adding more cannons.

Unfortunately, the Messerschmitt aircraft was initially conceived to be powered by a slim 700 hp engine.

The Gustav used a 1,475 hp DB 605 engine, 170 kg heavier, which was also fitted to use power-boosting devices like the MW 50 or the GM 1 which gave a gain of about 350 hp.

{In 1944, the German used a captured Spitfire VB to experiment the fitting of a DB 605 A engine of 1,475 hp. 
The Spitfire achieved a top speed 10 kph inferior to that of the Bf 109 G.

That may be not seen as a bad aerodynamics of the British fighter, which shape had not been modified since 1937, but as a good work of the development team of the Messerschmitt staff. }

Unfortunately, the skin of the cowling was affected by two symmetric bulges caused by the two new cannons fitted on the upper part of the cowling. 

These bulges affected negatively the streamlining of the Bf 109.

Bf 109 G6 Trop -   How to destroy a good streamlining: The left bulge is clearly visible.

Despite the increased power of the engine, the speed did not progress significantly.

Nevertheless, the Gustav variant climbed better than most Allied fighters as it can out dive also plenty of them. 

The last variant

The real solution against the B 17 or B 24 US bombers was found a bit too late: It was not to add new cannons to the existing engine-mounted cannon, but to use of a much more powerful engine-mounted 30 mm cannon.

Owing the deletion of the additional cannons, it was possible to recover the good streamlining of the Bf 109 F. 

It was incorporated in the last operational German variant, the Messerschmitt Bf 109 K (Kurfürst)

Some problems were encountered in the choice of the cannon itself, because there was two weapons, the lightweight (60 kg) MK 108 with a low muzzle velocity (540 m/s) and the heavier MK 103 (140 kg) with a clearly better muzzle velocity (860 m/s).

This last weapon had very better ballistic properties, allowing to shot from far longer distance, but MK 108 had a higher frequency. So the two cannons were mounted almost alternatively.

Bf 109 K -

{Source : The very good paper of Michel Ledet in Batailles Aériennes # 065 on the JG 53 German unit.}

The performances were:

  • Top speeds without MW 50 :
    • at sea level:       515 kph
    • at 8,400 m :       645 kph
    • at 9,000 m :       670 kph
  • Top speeds using MW 50:
    • at sea level:        580 kph
    • at   4,000 m:       662 kph   
    • at   7,200 m:       710 kph
    • at 10,000 m:       678 kph
Climbing to 10,000 m needed only 6' 30".

The service ceiling was 12,200 m.

The total range (without auxiliary tank) was 585 km.

The landing speed was 150 kph.

This fighter might not very easy to handle with her 2,000 hp - as were the Griffon engined Spitfire - and her engine was not reliable.

Moreover, the Kurfürst variant was to late to had a significant role on the event.

Most of the experten pilots had either disappeared (KIA, MIA or POW) or were transferred to Messerschmitt 262 units.

The German defeat was, in no way, a Bf 109 defeat. It had its roots in the wrong estimate of the economic and military situation of Germany in 1933.

If Hitler's third Reich was really a tremendous hazard for all his neighbors, he had not the demographic power, nor the technologic abilities to achieve his aims in the appropriate time.

Nevertheless, among the problems of the sole Luftwaffe, the idea of a standard fighter was absolutely not wise

When the battles were displaced far from the German boundaries, the Luftwaffe would have chosen to increase the number of its FW 190:
  • more safe for her pilots, 
  • more deadly with more weapons, 
  • more endurant with a better total range (from 810 km for the FW 190 A1 to the 2,000 km of the TA 154).

Adolph Galland confirmed in his memories than the RLM maintained the production ratio of four Bf 109 for each FW 190...

If you add the erroneous choice of jet fighters, implying the need of a different fuel and the necessity of a thorough perfecting of the Jumo turbojet...

Aucun commentaire:

Enregistrer un commentaire