Bloch MB.131

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Bloch MB.131
Bloch MB 131 San Diego Air & Space Museum 3.jpg
Bloch MB 131
Type: Bomb and reconnaissance aircraft
Design country:

FranceFrance France

Manufacturer:

Bloch

First flight:

June 29, 1934

Number of pieces:

145

The Bloch MB.131 was a bomb and reconnaissance aircraft developed in France in the mid-1930s . It was used in this role during the Battle of France in the Armée de l'air , but it quickly proved to be out of date and therefore suffered heavy losses against the German Air Force . After the capitulation of France, the remaining machines were used by the Germans and Vichy France , but not for combat missions.

construction

The type was originally designed under the designation Bloch MB.130 in response to a tender by the Armée de l'air for a bomb and reconnaissance aircraft with a crew of four ( RB4 ). The Société des Avions Marcel Bloch designed the aircraft as an all - metal low- wing aircraft with two radial engines , retractable landing gear and three machine guns for defense. The first prototype first flew on June 29, 1934 under the designation Bloch MB.130.01 . Although weaknesses were already revealed at that time, an order for 40 machines was placed in October 1935.

Since they were aware of the fact that the design was not yet fully developed, the type MB.130 was further developed to the improved version Bloch MB.131 before the actual production began . The corresponding prototype MB.131.01 had its first flight on August 16, 1936, but still proved to be faulty. Extensive revisions to the wings, fuselage and stern resulted in the third prototype, the MB.131.02 , which only took to the skies on May 5, 1937. A further 100 copies of this version were then ordered for the Armée de l'air.

As a further development, prototypes followed under the designation MB.132 (again revised rear and 940 PS Hispano-Suiza 14Aa engines) and MB.133 (with double vertical tail and even more powerful 1100 PS Hispano-Suiza L4 Aa engines). Since the first flight of these types was delayed by a year due to difficulties with the Hispano-Suiza engines, the two designs were already inferior to the competition at this time and therefore received no further attention from the Armée de l'air.

The MB.130 project finally led to the development of the four-engined medium bomber Bloch MB.135 with 710 HP Gnôme-Rhône 14M 6/7 engines as well as stronger on-board armament and bomb load . The prototype MB.135.01 took off for its first flight on January 12, 1937, which revealed very promising flight behavior. Although the performance of this aircraft was above those of the competing models Amiot 351 and Lioré & Olivier LeO 451 , it did not go into series production because the latter two types were already at this stage and the Bloch factories intended to produce the Bloch MB.174 were.

The total production number reached 145 machines:

  • 14 MB.131R4 , a pure reconnaissance version with only one MG in a central position
  • 5 MB.131Ins , training version with two control positions
  • 121 MB.131RB4 , the main version (bomber / reconnaissance aircraft)
  • 6 prototypes of different versions ( MB.130.01 , MB.131.01 , MB.131.02 , MB.132 , MB.133 , MB.135 )

commitment

In 1938 the type MB.131 took up service in seven Groupes de reconnaissance , six of which were stationed in France and one in North Africa . At the beginning of the Second World War , the MB.131 was in service with the following units:

The Armée de l'air used the machines in September 1939 for daytime reconnaissance flights along the western border of the German Reich . The Bloch MB.131 were sent out individually or in groups of two to investigate the progress of the work on the Siegfried Line . The reconnaissance flights took place v. a. on the lines Saarbrücken - Saarlouis - Merzig , Sarreguemines - St. Ingbert - Lebach , Forbach -Saarbrücken- Neunkirchen (Saar) and Saarlouis Bingen - Pirmasens - Worms instead. Although the missions initially showed little success, it quickly became apparent that the type without a hunting escort was de facto powerless against the German hunters of the Messerschmitt Bf 109 E type and therefore suffered high losses. The poor maneuverability as well as the poor quality of the MGs contributed to this, which always jammed. On September 18, the command was given to the squadrons not to cross the border during the day. In October, the same order was issued to the squadrons stationed in the south of France, whose task until then was to explore northern Italy (up to the Novara - Alessandria - Genoa line ). Then the squadrons equipped with the MB.131 only flew night missions. The Germans still often shot down, so that the guy was finally completely withdrawn from the front line and only used as a tow plane for target drones and for training crews. By the outbreak of the Battle of France in May 1940, all Groupes stationed in France had converted to the Potez 63.11 .

After France surrendered, some captured specimens were used by the German Air Force as tow planes and for transport and training purposes. The machines that were not captured by the Germans found themselves in the same role within the air force of Vichy France.

Technical specifications

Bloch MB.131RB4
Parameter Data
 length    17.85 m 
 height    4.09 m 
 span    k. A. 
 Wing area    54 m² 
 drive    two 950 PS (708 kW) Gnôme-Rhône 14N 10/11 air-cooled radial engines 
 Top speed    349 km / h 
 Rate of climb    5.1 m / s 
 Service ceiling    7,250 m 
 Range    1,300 km 
 Empty mass    k. A. 
 Takeoff mass    k. A. 
 crew    4th 
 Armament    three 7.5mm machine guns of type MAC 1934 in movable positions in the bow, stern (below) and movable turret (above),
800 kg bomb load 
Bloch MB.135.01
Parameter Data
 length    15.44 m 
 height    3.91 m 
 span    k. A. 
 Wing area    60.6 m² 
 drive    four 710 HP (520 kW) Gnome-Rhône 14M6 / 7 air-cooled radial engines 
 Top speed    500 km / h (at an altitude of 5,000 m) 
 Rate of climb    8.8 m / s 
 Service ceiling    10,000 m 
 Range    2,000 km (with 900 kg bomb load) 
 Empty mass    k. A. 
 Takeoff mass    k. A. 
 crew    4th 
 Armament    two 7.5mm machine guns of type MAC 1934 in movable positions in the bow and stern (below),
one Hispano-Suiza-HS.404 -20-mm- cannon in a movable turret (above),
max. 1,350 kg bomb load 

Countries of operation

Comparable patterns

literature

  • Dominique Breffort / André Jouineau / Alan McKay (translator), French Aircraft from 1939 to 1942 Volume 1: From ANF to Curtiss , Histoire & Collections, ISBN 2915239231 (English).
  • José Fernandez, Le Bloch 131 ; Article in magazine: Air Magazine No. 30, TMA SARL, Paris, March 2006.

Web links