dimanche 21 octobre 2012

The French Strike Air forces: The missing link...

The year 1934 appears now as a temporal node for the technology of military aircrafts. The military air forces around the World were using mostly bombers which cannot fly faster than 230 kph, but some more recent planes exist which were able to fly faster than 300 km/h.
If the US Martin B 10 was a little faster - 343 kph - she was the forerunner of a new generation of bombers gathering all the advances in the domain.

 For exemple, the Junkers 86 (325 kph) and the Dornier 17 (410 kph) bombers flew first at the end of 1934.
So, the French Air Ministry decided to launch 2 military programs for the procurement of fighters (top speed: 450 kph) and, four monthes later, bombers (470 kph).

Amazingly, the French deciders wanted bombers faster than their fighters, demonstrating an obvious complete lack of proficiency about what happens during a fight in the sky.

These deciders, likely, were persons who cannot reason in a three dimensional world. Their minds were overwhelmed by the fight between sea battleship in which the gun caliber was of paramount importance.

Furthermore, the bombers they wanted had to be twin-engined, but one such aircraft with 2 x 1000 hp can be seen, roughly, as using 3 fuselages, with 6 interactions zones with the wing. So, the drag of such a bomber is larger than the one of a fighter using of the same engine.

So, a previous program, known as BCR - Bombing, Fight (Chasse in French), Recce - has been near fruition in 1935. This program had the ill-ambition to give the aerial cruisers described in the book of general Giulio Douhet.
French deciders were not alone with such a vision, the Dutch decided to buy the Fokker T.V (417 kph) and to cancell the orders for Fokker D XXI fighters...

Nevertheless, there was 4 BCR prototypes which appeared in France. The first two of them to be ready were ordered, and it was not the best choice at all.

Potez 540

Among them was the Potez 540, with 2 Hispano-Suiza 12X engines of 700 hp.

She was a rather light bomber (less than 3900 kg empty), manoeuvrable, fitted with a retractable landing gear. Her top speed was 320 kph at 4000m (13250 feet).

Potez 540
fiche technique sur aviafrance

This plane was of mixed construction (for easier repairs). 
The bomb Load was 900 kg among them 500 kg were housed in the fuselage.
The defense used of 3 riffle caliber machine guns, inducing the stupid nose turret.
More than 250 were ordered.

They fought gallantly in Spain (to the Republican side with André Malraux who wrote one of his adventure in "l'Espoir").
When they were facing the FIAT CR32 of the Aviazione Legionaria without fighter escort, they were hopeless, as usually for any bomber facing modern fighters.
After the mass arrival of soviet planes, these bombers were vilified by the Russian as it's frequent between allieds. 
But, if the Potez 540 were clearly slower than the Tupolev SB2, they were fitted with self sealing fuel tanks, allowing a better resistance to gun fire.

An upgraded version appeared later, the Potez 544, with 2 Hispano-Suiza 12Y. 

The top speed might had been 350 kph but the ceiling exceeded 11000m, giving her an interesting role as spy plane. 

However, few of them were ordered. Neve.rtheless, this plane cannot be seen as more survivable than a Bloch 210

Bloch 131

The second aircraft ordered was the Bloch 131. 
This aircraft appeared as clearly more aerodynamic than all her forerunners.

Bloch 131
technical data

The Bloch 131 prototype was able to fly as fast as 385 kph. 

Unfortunately, she suffered from alarmingly strong vibrations. 
Due to a wrong interpretation of this phenomenon, some reinforcements were proceeded, adding more than 1000kg to the bomber. 

It was then discovered that the vibrations were induced by motor cowlings on the horizontal part of the tail. 

But, now, the French Air Staff was following the same stupid "fashion thinking" than the British one for the Witley and ask to Marcel Bloch a shorter take off run.
As for the Whitley, the solution found was to increase the angle of the wing. 
So, the Bloch lose 2000m of ceiling and 35 kph in top speed, at 350 kph. 
Her bomb load was only 800 kg.

Pilots were able to make aerobatics with this plane, but was it so usefull?

More than 140 of this bomber were manufactured ans given to recce squadrons. 

But, used without fighter escort for recce in 1939, they suffered heavy casualties and were withdrawed soon. 

Two better contenders would have been chosen. They were later, because they were more advanced.

Bréguet 462

The first one was the Bréguet Br.462, the perfected progeny of the Br.460, an interesting aircraft able to fly at 385 kph but with too many problems (even most of them have been solved when she was given to the Spanish Republic).

The Bréguet 462 

This new aircraft was aerodynamically refined, stable, reliable, faster and more manoeuvrable.

She had a top speed of 405 kph, a ferry range of 3000 km, a ceiling of 8300m and abomb load of 1500 kg.

It was one of the very few aircraft for which the CEMA had not expressed criticisms!

One bomber was ordered by Japan, the other by USSR, only to study the Bréguet process.

She was not ordered for France, as it was written by engineer Louis Bonte, "because she did not correspond to the new program B4, for which the Lioré-Olivier 451 was the type" (Histoire des essais en vol, Docavia #3, 1974). 

What a spectacular example of bureaucratic literature! 

So, France was continuing to manufacture one year more several dozens of Bloch 131 flying at most at 350 km/h. 

And these bureaucrats were refusing to order a very better plane, flying 50 kph faster, able to use twice the bomb load!
Moreover, with the better engines available in 1938, the Bréguet 462 could be able to fly even 25 to 40 kph faster, being strictly competitive with the Heinkel 111 P of 1940.

Obviously, as quite all bombers, she would need fighter escort. 

But the time needed to complete a bombing mission could have been significantly shorter than for all previous bombers. 

Furthermore, the Bréguet 462 was ready to be manufactured in time for being operational at the beginning of 1938, giving to Mr Daladier - equivalent to Prime Minister for France - an opportunity to make a more courageous choice at the Munich conference.

Another argument is that the availability of such a plane allowed the perfecting of the B4 bombers among them no one was ready to go to war.

Apparently, none of the French actual decider was aware of the time needed to engage a completely new industrial process, including all the new technological equipments.

The second chance wasted

Previously, I told you there were 2 contenders wrongly rejected.

The second one was the Amiot 340

A very advanced aircraft, able to fly at 480 kph.

I will told you about her in another post, soon.

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