In July 1934 Avions
Mareel Bloch was a contender in a design competition which resulted
from a French air ministry specification for a new fighter. Submissions
were received also from Dewoitine, Loire, Morane-Saulnier and Nieuport,
with Morane-Saulnier eventually selected as the winner. So far as Bloch
was concerned, this was no close-drawn decision with its design team
chewing its finger nails because it had been beaten to the pylon by the
thickness of the paint skin on the propeller. True, it was biting its
finger nails; but this was probably because its Bloch M.B.150.01
prototype could not be induced to part company with the security of
mother earth.
Nothing further
happened for about nine months until, in early 1937, it was decided to
force the 'ugly duckling' into the air. This was achieved in October
1937 after the provision of a strengthened wing of greater area,
revised landing gear, and installation of a 701 kW (940 hp) Gnome-Rhone
14No radial engine with a three-blade constant speed propeller. Handed
over to the Centre d'Essais du Materiel Aerien (CEMA) for service
trials, its performance proved sufficiently interesting to warrant
further development. This brought, at the very beginning of 1938, a
small increase in wing span and installation of a Gnome-Rhone 14N-7
engine. When trials were completed in the late spring of 1938, SNCASO
was awarded an order for a pre-production batch of 25 of these
aircraft.
Preparatory work before
initiation of construction of the aircraft, in a new SNCASO factory,
brought realisation thatdesignoftheM.B.150.Ol was totally unsuited for
mass production. The only solution was another redesign, during which
wing area was reduced and the Gnome-Rh6ne 14N-11 engine selected for
installation. It was in this form that a new prototype, redesignated
M.B.151.01, flew for the first time on 18 August 1938. Construction of
the balance of the pre-production order had already started by then,
but despite the growing urgency of the situation only four of these
aircraft had been delivered by April 1939. Simultaneously, SNCASO's
design team had been working on an improved version, but the only
significant difference between this and the M.B.151.01 lay in the
installation of a 768 kW (1,030 hp) Gnome-Rhone 14N-21 engine. First
flown in December 1938 the new prototype, designated M.B.152.01, was
provided with the slightly more powerful Gnome-Rhone 14N-25 before
being handed over to the CEMA for flight testing in February 1939. The
improved performance of this version created positive reaction, with a
firm order being placed for 400 production aircraft, of which 340 were
to be M.13.152s, the balance the earlier M.B.151s.
Three view diagram of the Block MB-152
Unfortunately, equally
positive action did not materialise on the production line, and by the
out-break of World War 11 in September 1939 a combined total of 120
M.B.151 and M.B.152s had been delivered. Even more unfortunately, not
one of these could be used in action, for all were without gunsights
and 95 of them could not be used at all, for they had been delivered
without propellers. This was the moment when pressure of circumstances
should have eliminated all petty difficulties, but even by the end of
November, at which time 358 had been delivered, 157 were still without
propellers and there were serious problems with engine overheating
which needed attention.
Despite the problems,
the Armee de I'Air did everything possible to speed introduction of
what was potentially a valuable addition to its inventory. An
experimental squadron was formed in September 1939, and initial
deliveries to the fighter groupes began in the following month. Initial
unit to convert to the type was Groupe de Chasse Ill, and by the end of
1939 newly equipped groupes included II/1 and II/10, III/9 and III/10,
and the French Navy's Escadrille AC-3. All were to discover that their
M.B.151s and M.B.152s possessed the desirable attributes of a combat
aircraft, and it was tragic that indifference and political intrigue
forced so many courageous pilots of the Armee de I'Air to lose their
lives in obsolete aircraft, instead of being able to contest the
Luftwaffe on more equal terms with fighters such as the M.B.152.
When the German
armoured Divisions swept through France in May 1940, Groupes I/8, II/8
and II/9 had also been equipped with these fighters and, just before
this, nine M.B.151s had been supplied to the Greek air force. After the
collapse of France and conclusion of the Franco-German Armistice, six
groupes of the Vichy French air force retained M.B.151 and M.B.152
aircraft, namely I/l and I/8, II/1, II/8 and II/9, III/9, and when
SNCASO production ended at the same time a total of more than 600 had
been built. When, subsequently, three of these groupes were re-equipped
with Dewoitine fighters, the M.B.151s and M.B.152s were handed over to
the Romanian air force.
The only variant
comprised one M.B.153.01 prototype, an M.B.152 taken from the
production line and re-engined with a 783 kW (1,050 hp) Pratt & Whitney
R-1830-SC3-G Twin Wasp engine.
Specifications (Bloch
MB-152)
Type: Single
Seat Fighter
Design: Marcel
Bloch
Manufacturer:
SNCASO
Powerplant: One
1,080 hp (805 kw) Gnome-Rhone 14N-25 or a 1,100 hp (820 kw) 14N-49
14-cylinder radial piston engine.
Performance:
Maximum speed 320 mph (515 km/h) at 13,125 ft (4000 m); maximum
cruising speed 280 mph (450 km/h); service ceiling 32,810 ft (10000 m).
Range: 373 miles
(600 km) with internal fuel stores.
Weight: Empty
4,453 lbs (2020 kg) with a maximum take-off weight of 5,908 lbs (2680
kg).
Dimensions: Span
34 ft 7 1/4 in (10.55 m); length 29 ft 10 1/4 in (9.10 m); height 12 ft
11 1/2 in (3.95 m); wing area 161.46 sq ft (15.00 sq m).
Armament: Two 20
mm Hispano 404 cannon (60 round drum each), and two 7.5 mm (0.295 in)
MAC 1934 machine guns (500 rounds each) or four 7.5 mm (0.295 in) MAC
1934 machine guns.
Variants: MB-150
(first prototype, but it was such a bad aircraft, it never flew),
MB-151 (much improved MB-150 redesign with a Gnome-Rhone 14N-11
engine), MB-152 (upgraded engine), MB-153-01 (a stock MB-152 with an
American engine).
Operators:
France (Armee de l'Air, Vichy AF), Greece, Romania.
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