The Bloch MB-152 was a further refinement of the MB-151 single seat fighter aircraft, itself an improved version of the MB-150 that had originally been ordered in 1938. The original order for 475 MB-151s was altered to one for 144 MB-151s and 288 MB-152s.
The MB-152 had a slightly wider wingspan than the MB-151. The first 144 MB-152s used the Gnome & Rhône 14N-25, the rest the 14N-49, which provided 1,120 hp. The MB-152 with the 14N-49 engine had a top speed of 310mph at 18,000 feet, a 30 mph increase over the MB-151. This made it faster than the M.S. 406 but slower than the Dewoitine D.520, and more significantly a good 30 mph slower than the Bf 109E.
The first MB-152 flew on 15 December 1938. The Armée de l’Air received its first MB-152 on 7 March 1939. Tests over the summer of 1939 revealed several problems with the aircraft, including a serious lack of engine cooling, which reduced the aircraft’s maximum speed. A variety of different engine cowling and propeller combinations were tried in order to solve this problem. Early production MB-152s used the widest aircraft cowling tried, with a 1000mm diameter, which solved the heating problems but at the expense of performance. Later in the production run this was replaced by a more efficient 850mm diameter cowling. Only aircraft after No. 501 in the production run (which included the MB-151) carried all of the required modifications and were considered fully combat ready. Other aircraft were to be converted to the new standard, but the German invasion began before that process could begin. Finally, a revised and improved design, the MB-155, was to have replaced the MB-152 on the production lines. A very small number were completed before the collapse, but did not enter combat.
At the start of the German invasion on 10 May 1940, the French Air Force had 363 Bloch MB-152s. However, 195 of these were the earlier model with the 14N25 engine. Of the remaining 165 only 80 carried all of the modifications required by the Air Force. Seven units were equipped with the MB 152, although three of them still had some MB 151s on strength. On 10 May 93 Bloch 152s were operational, with another 53 in reserve. Another 200 MB-152s joined operational units during the fighting. At the end of the fighting there were 140 MB-152s and -151s still operational. Only once it was too late did French aircraft production really begin to pick up.
The MB-152 was a disappointment in combat. Although it was a steady gun platform and could take a great deal of damage and still return to base it had several serious problems. It was too slow, and climbed too slowly. It had too short a range to be effective, especially as France had no radar system. The unheated guns were prone to freeze at altitude. The MB-152 scored 146 confirmed kills, putting it well behind the 230 claimed by the Hawk H-75, which was present in rather smaller numbers.
The MB-152 remained in service with the Vichy Air Force. It did not have the range to escape to North Africa. Six fighter squadrons retained the MB-152 after the armistice, each with 24 aircraft, more aircraft than had been operational in May 1940. In April 1941 it was agreed to standardise on the Dewoitine D.520. The changeover was almost complete when the Germans invaded the unoccupied zone at the end of 1942.
Statistics (for final version)
Span: 34 feet 8 1/8 inches
Length: 29 feet 10 11/16 inches
Engine: Gnome & Rhône 14N-25 air cooled radial engine giving 1120 hp
Speed: 310 mph at 18,000 ft
Ceiling: 32,800 ft
Guns: two 20mm HS 404 cannon (60 rpg) and two 7.5mm MAC 1934 machine guns (500 rpg).