BRISTOL TYPE 142M BLENHEIM
I (see also the Bristol
Type 149 Blenheim IV and the Bristol
Type 149 Blenheim V) - The Bristol team headed by Frank Barnwell designed
the Type 142M during 1935 as a three-seat light bomber derivative of the
Type 142 Britain First, the major differences being raising the
wing to a mid position to make room for a bomb-bay in the fuselage, adding
nose and dorsal armament plus a bomb-aiming station in the nose, the raising
and enlarging the tailplane. A contract for 150 Type 142Ms to Specification
28/35 was placed by the Air Ministry in September 1935 and the name Bristol
Blenheim was adopted in April 1936.
Bristol Blenheim I: Production contracts for 150 in 1935 and 434
in 1936, and 134 in 1937 to make a total of 718 built by Bristol, plus
250 by Avro at Chadderton and 422 by Rootes Securities at Speke. Two 840
hp Bristol Mercury VIII engines. One fixed for-ward-firing 0.303-in (7.7-mm)
Browning gun in port wing and one 0.303-in (7.7-mm) Lewis gun in Bristol
B.I Mk I powered dorsal turret. Internal bomb-load, 1,000 Ib (454 kg).
First production Bristol Blenheim I flown June 25, 1936; initial deliveries
to No 114 (B) Squadron in March 1937, and 16 other home bomber squadrons
and 13 overseas bomber squadrons equipped, 1-937-39. Bristol Blenheim
I bombers out of front-line service in UK by September 1939 but operational
overseas, notably in the Western Desert and Greek theatres. Bristol built
18 Bristol Blenheim Is for the Finnish Air Force (Ilmavoimat) in 1937-38,
adapted to carry Swedish bombs and to operate on skis, supplemented early-1940
by 12 ex-RAF Bristol Blenheim Is, and Finland's Valtion Lentokonetehdas
at Tampere built 45 Bristol Blenheim Is under licence, the type being
operational in the Winter War and Continuation War with LLv 42, 44, 46
and other units. The Yugoslav government purchased two Bristol Blenheim
Is in 1937 and a licence to build 50, of which 16 had been completed by
Ikarus AD at Zemun by the time of the German invasion in 1941, being supple-mented
by another 20 ex-RAF in 1940, some adapted to have two 20-mm forward firing
cannon. A few of the Bristol Blenheim Is that survived the fighting in
1941 later served with the Croat Air Force. The Turkish gov-ernment purchased
30 Bristol Blenheim Is, deliv-ered late 1937-February 1939, and in November
1939, 13 ex-RAF machines were supplied to Romania.
Bristol Blenheim IF: About 200 bomber Bristol Blenheims adapted
as twin-engined fighters, with a pack of four fixed forward-firing 0.303-in
(7.7-mm) Browning guns under the fuselage. Initial deliveries to No 25
Sqn, December 1938, and used by several squadrons at home and overseas
for day and night fighting. Some fitted with AI Mk III radar for operational
trials, gaining a first success on 2/3 July 1940.
Bristol Blenheim II: A single Bristol Blenheim I (LI222) with long-range
tanks and gross weight of 14,000 Ib (6,356 kg), with provision for extra
bombs externally under inner wings.
