samedi 6 octobre 2012

How to intercept German Airplanes in the 1940 France? (revised)

This post complements my previous one on "the Luftwaffe is attacking....

Different targets implied different stricking aircrafts... and different fighting defense methods

In the first European act of the WW II, the action of the enemy Air Force in our territories was regarding some targets enumerated there.

The Luftwaffe used various kind of planes in accordance to the methods retained to strike the chosen targets:
  • The strategic recce flights were performed mostly by Dornier 17 P until the summer of 1940. They may fly at 8,000 m were they were absolutely immune to the Morane 406 French fighters. During the Battle of France, according to my present knowledge, there was no high flying Junker 86 P, which were only used as prototypes (they were used first during the Battle of Britain).
  • The massive strikes against industries, airfields, army concentrations or, even, center of crowded towns (see Rotterdam, May 14, 1940) were performed by groups of classical bombers as the Heinkel 111 or Dornier 17.
  • The strafing at very low flying level - less that 150 feet - needed the use of very fast and nimble planes as were the Messerschmitt Bf 109 and Bf 110 (they were fastest at sea level than any other Allied fighters in May 1940). Even they were able to avoid some burst of gun fire, such light fighters were rather vulnerable to light machine-guns AA fire. However, our fighters were not very efficient against them, because their pilots would experienced some difficulties to see them clearly when they were flying very fast in the vicinity of the ground among a lot of landmarks. Another cause of inefficiency of our fighters against the strafing attacks may be due to the fact that flying fast at low level may increase the motor temperature if the flight was a long lasting one.
  • The high accuracy bombing in vertical dives were performed only  by the Junkers 87 Stuka, beginning their dives at 3-4,000 m. They may be countered by both AA fire and fighters. Nevertheless, the AA fire needed more effective guns than machine guns. The Hotchkiss 25 mm guns would have been perfect in this role, but the French Army had less than 350 of these guns in May-June 1940 (!). The protection of the Allied hot spots by our fighters was possible by combat air patrols above these spots. The Morane 406 which was completely inefficient as an interceptor, was able to obtain good results in such a work.

The first 2 cases are those which implied absolutely a good ability to intercept the enemy aircrafts.

As you know, obviously, this interception implied first a good warning system.

Defending France skies against the recce planes

The case #1, the strategic recce was of paramount importance. 

The informations obtained this way allowed the German high staff to define both the strongest part of the French defense as also their weakest ones.

So, the general Heinz Guderian could obtained the informations that the fences in the vicinity of Sedan were not very strong since many months before the outbreak of the WW II and, also, that they have not been reinforced before the May, 1st, 1940 (H. Guderian, Memories of a Soldier, 1954).

It seems that, in the 1940 France, the interception case for planes flying up to 8,000 m (~26,500 feet) may be divided in 3 solutions.

  • Using first the best climbing fighters, with - may be - less fuel and ammunition to gain some precious seconds. It was a correct solution if the warning was given sufficiently early.
  • Sending two fighters in CAP at middle altitude to wait for the warning. This could be very efficient, as also fuel consuming. A relief was necessary every hours or every times the former patrol was used for more classical interceptions.
  • Stuck the pilots in their planes waiting for the warning. This mathematically correct solution of, so-called super-warning, was especially bad for France, owing to its bad warning system. The pilots were becoming more and more nervous with time and thought they were wasting their time for peanuts. 
Obviously, French Air Command chose this last inefficient solution (while the German used of the second - and best - one, designated as frei Jagd  = free hunting).

The famous movie the Battle of Britain (1969) explained very well how to achieve the interception: Immediately after their landing, all the fighters were replenished in fuel and ammunition and the pilots again ready to combat. 

When the warning was given, they had 120 seconds to take off. 

Yes, it was very difficult, but most of them had achieved successfully such an objective.

Almost one year earlier, during the first months of the of the Phoney War, the leader of the squadron chosen to experiment seriously the Bloch 152 fighter, wrote that the best delay between the warning and the take off was 4 minutes.

The striking difference with the English pilots of the Battle of Britain was the sportive training and the consciousness of the reality of the War. 

It was very different from the behavior of the French pilots of the previous World War.

OK, the French pilots ware late to take off, but the British pilots seemed not better performer until the Battle of Britain. 

(Nevertheless, the lack of ceiling of the British fighters allowed some immunity to the Junkers 86 P spy planes until late 1942.)

About the climbing performances

The interception ability of the French Air Forces fighters was directly depending from their climbing performances.

Personal document of the author - Climbing times of the FAF fighters + those of the Nieuport 161, the best one...

Regarding the interception of a raid of Luftwaffe bombers flying at 4,000 m (~13,250 feet), the 2.5 minutes delay between the best climbing fighters and the worst ones may not had an extreme tactical importance. 

After the climbing, the level speed was a key factor to catch the enemy bombers.

However, if the raid was flying just 1,000 m higher, things became more complicated for a Morane-Saulnier 406.

In this case, the pet of the CEMA needed, altogether, the quarter of an hour to achieve the climbing. 

When the Morane was at the good altitude, she had no chance to deter the bombing and she must try to pursue them, quite hopeless. 

At that moment, the German fighters was on her back to welcome her, warmly...

May be you want to remember me the 175 to 188 victories obtained by the Morane? 

You are right, but many of them resulted from random encounter as the German, being attacking, were very numerous in the sky.

For the Caudron-Renault Cyclone CR 714, the curve is quite the same as for the true Morane up to 5,000 m, but a little better above (yes!).

The Curtiss H75 (P 36 for the US) was - using her 5' military power - the best until 4,000 m. 

After, it was necessary to wait 20 minutes for cooling the engine... 

The best solution for them to intercept a spy plane was a CAP at 5,000 m.

The good situation awareness of her exceptional pilots explain clearly the good interceptions they achieved.

The Bloch 152 of 1939, with her huge air intake of the cowling, was nevertheless clearly superior to the Morane 406. 

In May 1940, most of them had a better motor, exhaust pipes and the best cowling: They would climb even better.

The best of the French fighters was undoubtedly the Dewoitine D.520. 

If she was introduced in the good time, she was able to down most of the spy planes.

Against the German raids, she was absolutely efficient... when the warning was correct, of course.

I have also given the times obtained by the prototype 02 of the Nieuport 161.
  • They demonstrate how short sighting were the French deciders when they chosen the Morane fighter, which lost more than 11 minutes to reach 8,000 m.
  • The Messerschmitt Bf 109 E shared the same performances up to 7,000 m. But the Nieuport was 90 seconds faster to reach 8,000 m.
  • The Dewoitine 520 was able of quite as good performances as the Nieuport.

The interception case, not clearly understood in the 1940 France, was shared by all belligerant countries 

The exigencies of the Air Chief Marshall Dowding to obtain his pilots they took off in at most 2 minutes after the warning signal display how difficult was the interception of the German raids, despite the radar control and the good performances of their fighters.

During the Battle of France, the 100° octane fuel was not currently available and the constant speed air screw were very few. 

So, the beautiful performances of the British fighters published everywhere were not present during the actual combats.

Personnal document of the author - Climbing times of the RAF fighters with the DH 2 pitchs airscrew + those of the Nieuport 161

The diagram above displays how difficult the interceptions were for the British fighters in France, without their radar based warning system.

Some few years later, like the others, German Luftwaffe experienced the impossible task of intercepting the Mosquito bombers which were flying fast at relatively high level.

However, the German radars were very good, the warning system were also at the state of the art, but their fighters were not sufficiently fast.

General A. Galland wrote in his war memories how he was alleviated, in 1944, when a patrol of bi-reactors Me 262 took off to intercept the British bombers. 

But it was too 6late. 

The best warning system could not create pilots or fighters once they have been destroyed.

Russian, with the Mig 3, had a rather good interceptor, very fast (640 kph) and climbing decently in 1941 (8,000 m in 10'30"). 

But the warning system was not very efficient. 

Fortunately, the huge area of the country allowed the take off of their fighters just in time.

The Japanese fighters climbed very well up to 6,000 m (20,000 feet) but, initially, the warning system was nonexistent over the National territory (that explaining the success of the Doolittle raid over Tokyo in 1942).

The later fighters were very good performers, as was their warning system, but most of the well trained and experimented pilots have been wasted, giving to the superlative B29 bombers a perfect opportunity to destroy the economic and military structures of the country.

At Pearl Harbour, in December 1941, the USA used a state of the art radar with well trained observers. 

They warned largely in time the military deciders who might dispose of a lot of fighters and pilots (as also of AA guns). 

But the local high command was as stupid as the staff of the French general Corap at Sedan the May 12, 1940. 

They refused to do any thing. 

You know perfectly the consequences...

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