The difficult beginning of an exceptional success story
(the main sources used to write the following post was: The “bible” for the MB 15x fighters: The Bloch 152, by Serge Joanne, Lela Press; The series of articles in the Album du Fanatique de l’Aviation; The testimonies published in Icare [serie: La Chasse]; Several very interesting papers in Avions and in Aéro-Journal)
If, today, this fighter may be seen as very classical, it was not the case in mid-1936.
First, it used a radial engine, a kind of engine inducing automatically a bulky nose, signifying some loss of performances for aerodynamic reasons.
Unfortunately, the take off could not be achieved already.
So, engineer Roussel was fired.
But, it was not the true motivation, which, in fact, was only to give some comfortable jobs to some incompetent lobbyists (it's more easy to see that from today).
So, Marcel Bloch (as, among the others, Mr Henry Potez or Emile Dewoitine) became “administrateur délégué”, but he had not the liberty to do what he feel the best: Before any action, he needed to submit all his decisions to some committees....
Various factors explained the failure of the maiden flight of MB150.
A fine general conception
|Bloch MB 150 - (after her maiden flight)|
For example, her wings was very thin (14% of thickness) and her fuselage was well streamlined. The only clumsiness of the Bloch design may be found in details (which were all successively eradicated).
In French specialized publications, one can read - to explain the revival of the MB 150 - the French Air force Staff was concerned about possible shortage affecting the Hispano-Suiza 12 Y engines needed for the Morane 406 fighter.
The Air Staff had previously chosen the Nieuport 161.
But, after her crash, the Nieuport was vilified, excluded from the contest (!) and the active lobbying of some politicians achieved the ordering of the Morane 406.
So, they sent some cautious messengers to MM Bloch, Dewoitine and Renault to ask them to resume their works.
This behavior is always possible in every country...
Marcel Bloch had previously never been involved in the design of any high performance plane.
So, as any engineer creating a fighter dynasty, he had (as all his staff too) to learn all the high speed aerodynamics and its associated structural consequences.
Even the engines were not bad at all, they became so powerful that a complete redesign was needed to take into account a lot of new constraints.
This redesign was done, leading to the 1600 hp class Gnome et Rhône 14R Météor, unfortunately a little too late.
OK, may be, do you think it was stupid to do three times the same work while Hitler and his Nazi Reich was so close of triggering the WWII. You are right...
|MB 151 prototype, with the efficient cowling of 0.85 m in diameter - photo on the site aviafrance|
Unfortunately, this later cowling was never used for the MB 151...
The top speed of this last fighter was, at least, 460 kph without exhaust pipes.
|serie MB 151 with the huge air intake of 1m in diameter|
the original legend is MB 152, but its impossible: it lacks the wing cannons HS 404
And we know today, the cooling of her engines was good above 240 kph.
With a speed of 460 kph, the MB 151 experienced some difficulties to catch some bombers.
Fitted with the best cowling and the exhaust pipes, the MB 151 could had reached a far better fate.
May be, Marcel Bloch could have taken some advantage if he had chosen the efficient - but very complicated for maintenance purpose - Mercier cowling...
|MB 152 on aviafrance site - the leftest plane is fitted with the "good" cowling, the following, not, but all display their starboard canons !|
The MB 150, starting with a to speed of 434 kph, culminated, with the same layout, to 515 kph.
This progression of 80 kph was obtained together with better handling qualities and better lateral stability and, even, a complete redesign to divide the aircraft in modular blocks for a faster building: a lot of work in a very short time
The MB 151 was used by at least the GC II/10 and III/10, in the French Air Force, and by the Aéronavale squadron AC 3.
The three patrols of the AC 3 took off just in time (a few time before noon).
They were overwhelmed (9 vs 27), 2 pilots were killed in action, another one (SM Le Bihan) died after a forced landing ended by a collision with a tree.
The peculiar fact is that this pilot, before his forced landing, collided voluntarily with a Fiat CR 42 fighter, which was downed.
According to the testimony of a French artillery officer, they have not be destroyed by the D 520 of the GC III/6 which were still on the ground.
This was the same behavior for the British in North Africa against the Italian fighter, preferring to be downed by Germans.
Unfortunately, when the Greeks ordered 24 MB 151, the Germans were about to launch their Fall Gelb against France and all democratic countries of Western Europa.
So, only 9 MB 151 were delivered to Greece. All of them have been previously used by the Armée de l’Air and their engines were worn out.
The Greeks having got no spars, so they used only 5 MB 151 fighters, the others being used as spars sources.
They appeared fairly efficient against the Regia Aeronautica.
But, when the Germans interfered, only 2 were still airworthy, and in few days they were eradicated.
Even in the worst definitions, they can fly at least 30 kph faster, but those which were fully operational were able to fly at least at 505 kph at altitude, to climb to 4000 m in 6’12” and to reach 8000 m in less than 16’.
With a VNE of 660 kph (IAS), they were able to dive faster than the Curtiss H75 (VNE : 550 kph IAS) and also faster than the actual Hurricane (Jean Nollet, in Album du Fanatique de l’Aviation, #11).
Irrelevant starting position
Some of these “big” units were gathered in Zone d’Opération Aérienne, the two ZOA illustrated in this map gathered 630 single engined fighters over a grand total of 900 for all the French Air Forces (including the Morane 406 available in Lebanon[!] ).
|Personal document of the author - Locations of the French fighters groups for the May 10, 1940|
Four others GC (1 on Bloch 152, 3 on MS 406) were a little more far from the Belgian border.
All these GC seemed dedicated to the protection of Paris and also to protect the limit between the tough Maginot Line and the less protected one (Ligne Maginot Prolongée).
It claimed only 4 victories during the Battle of France.
This poor score is the consequence of an irrelevant warning system as also of the bad positioning of this GC.
The organisation by GC had divided by a bit more than two the number of the airfields, allowing some reduction of the mechanics.
But the take off points were also reduced by the same amount, and, knowing the poor training of most of the AA artillery protecting the airfields, the Germans attacks were more “juicy”.
In the actual France, somebody thought the fighting did not give experiment!
The obsolete Morane 406 could have been used to protect the factories and the great cities.
She was used a much more sophisticated cowling, a more streamlined fuselage.
A 700 l fuel tank was fitted (300 l more than the MB 152), as, also, a 40 mm thick triplex windscreen.
The top speed published of 520 kph.
This is likely the lowest top speed accepted by the French Air Force for fighter just out of the plant.
The true top speed could have been about 530 km/h, the same than the Bloch 174 recce twin engined which used the same engines and the same cowling.
Captain Coutaud have got a victory with her.
A more powerful engine (~1200 hp) was about to be available for her.
|Bloch MB 155 - on a muddy airfield, but showing all the differences with the MB 152. The triplex windscreen is beautiful.|
The last Bloch fighter belonging to this family was the Bloch 157. You may read my post on her: Click here.
In 1940, despite all the success obtained by Marcel Bloch, the lobbyists have won, and Marcel Bloch was fired from his job.
After the defeat, as a jew, he was put in custody by Vichy police near Lyon and, after the German occupation of the so-called “free” France, at Drancy.
In August 1944, he was deported to Buchenwald nazi concentration camp, where he was protected by French communists militants (!).
Three years later, he changed definitively to Dassault.
The nationalized companies were working on very heavy fighters, the best one being the SO 6020 Espadon designed by Lucien Servanty.
He know better the financial and technical problems in the actual France than the so-called high-engineers, and preferred a much more light plane: That was the MD 450 Ouragan, which used a lot of structural solutions of the MB 150!
The lesson which one may derive from that story is how important is that Marcel Dassault had demonstrated a perfect capacity to adapt himself and his planes to any situation, and he had learn how essential is the independance of his Nation.