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Britain's Bristol Blenheim bomber^1,2,3,4,5

Bristol Blenheim bomber:	Bristol Blenheim bomber with the 68th Squadron:	Bristol Blenheim bomber with the 68th Squadron:	Bristol Blenheim bomber with Canada's Bolingbroke Mk IV, 254 Squadron:
Bristol Blenheim bomber with Canada's Bolingbroke Mk IV, 254 Squadron:	Bristol Blenheim bomber:
Bristol Blenheim bomber:	Bristol Blenheim bomber:

Design

Lord Rothermere, a newspaper owner, had asked Blenheim to make him the fastest commercial plane in Europe.⁵ The Blenheim was designed from the Bristol Type 142 light transport.^3,4 As the Blenheim was faster than any of the Royal Air Forces' fighters of the time, it was ordered straight from the designs.³

Once the war started some models had a rear firing remotely controlled turret under the nose.¹

A fighter version had a pack under the fuselage with four machine guns.¹

Construction

The Blenheim was constructed of all metal materials.⁵ The wings were positioned midway up the fuselage.⁵

Engine

The engines drove variable pitched metal propellers.⁵

Crew

Some felt that the navigator's compartment was very small in Blenheim Mk Is to Blenheim Mk IIIs.¹ The Blenheim Mk IV improved this space.¹

Armament

The Blehheim Mk I only had a forward firing Browning MG and a turret mounted Vickers MG for self defense.⁴

Prototype

The Blenheim Type 142M prototype first flew on April 12, 1935⁵ / June 25, 1936.^3,4 At the time it was the fastest plane in the world.⁵ Several trials were conducted at Mattlesham Heath with a dummy turret.⁴ Full scale production was allowed to go forward in December 1935.⁴

The Blenheim Mk IV first flew on September 24, 1937.³

The Blenheim Mk V first flew in February 1941.³

Production

An initial order of 150 was placed in September 1935 straight from the drawing board.⁴ In July 1936 another 434 more were ordered.⁴ This was later raised by 134 more.⁴

Bristol (at Filton⁴), Rootes (at Speke⁴), and Avro (at Chadderton⁴) built the Blenheims.^1,4

• Blenheim Mk I: 1,427³, 1,552⁵, 1,568 ordered⁴
  • Manufacturer:
    • Bristol: 694³
    • Avro: 250^3,4
    • Rootes: 422³
    • VLT (Finland): 45^3,4
    • Ikarus (Yugoslavia): 16^3,4
  • Production: 1936 - 1939⁵
• Blenheim Mk IV: 3,296³
  • Manufacturer:
    • Bristol: 313⁴, 316³
    • Avro: 750^3,4
    • Rootes: 2,100⁴, 2,250³
    • VLT (Finland): 10^3,4
    • Fairchild (Canada), "Bolingbroke": 656⁴, 676³
  • Production: 1939 - ?⁵
• Blenheim Mk V: 942⁴, Rhodes 945³
• Total: 3,297¹, 4,440², ~5,500⁵

Variants

• Blenheim Mk I: In production until late 1938.¹ Entered service in early 1937.³
• Blenheim Mk IF: Was a short nosed model that was in service through 1940 as a night fighter.² Had four 7.7 mm MGs under the fuselage.² 200 Mk Is were converted.³
• Blenheim Mk IV: First 80 has less powerful engines, and less fuel.¹ Had longer nose and the stepped nose.^2,3,4,5 Deliveries started in January 1938.³ It was to be used by Coastal Command as it met their requirements.⁴ More fuel tanks were installed to increase range.⁵
• Blenheim Mk IVF: Night fighter.³ Had the same ventral gun pack that was in the Mk IF.³ Starting in 1939, 125 were converted.³ Had self sealing fuel tanks.³ Armor was also added.³ Used a AI Mk III radar.³
• Blenheim Mk V also known as Bisley³: Close support.³ Was slower, but outfitted 10 RAF squadrons in North Africa and the Far East.¹ Had the Mercury XXX engine.² There were four guns in the nose.³ Entered service in November 1942.³
• Blenheim Mk VD: Was modified to fly in the tropics.² First used in North Africa at the end of 1942.²

Usage

The countries that used the Blenheim was Britain, Canada, Finland, Greece (10⁴)¹, Hungary, Portugal¹, Romania, Turkey (17⁴), and Yugoslavia.^3,4

RAF squadrons started receiving the Blenheims in March 1939.¹

The Blenheim was the RAF's principal light bomber at the beginning of World War II.²

On September 3, 1939, a reconnaissance flight over flew the German border.¹ The first RAF bombing raid was conducted by Blenheim Mk IVs.¹ The Blenheim Mk IVs outfitted seven RAF squadrons.³

First Unit

In March 1936⁴/March 1937 the No. 114 Squadron was the first unit to receive the Bristol Blenheim Mk I.^2,4

In January 1937 the first unit equipped with Blenheim Mk Is became operational.⁵ By the end of 1937 15 more units received the Blenheim Mk Is.⁵

Munich Crisis

By the time of the Munich Crisis of September 1938 there were 17 squadrons equipped with Blenheims.⁴ Seven squadrons in No 1 Group, six in No 2 Group, and four in No 5 Group.⁴

First Mission on September 3, 1939

The No 139 Squadron sent a Blenheim IV (N6215), flown by Flag Officer McPherson, to photograph German naval units at Wilhelmshaven.^4,5 No flak or Luftwaffe units were encountered.⁴ The next day McPherson was sent out again.⁴ The 107th and 110th Squadrons attacked the German fleet.⁵ McPherson eventually received the Distinguished Flying Cross.⁴

Battle of France

The Blenheims suffered heavy losses during the Battle of France.³

First Night Victory

The first night AI victory was scored by a Mk IF on July 22, 1940 against a Dornier Do 17Z.²

Night Battles

From 1939 there were 24 RAF squadrons that were equipped with the Blenheim Mk IF night fighter.³

Middle East

The Blenheim Mk IVs started being delivered to the Middle East in early 1940, replacing Mk Is.³

Last Operation

The Blenheim Mk IVs last operation was on August 18, 1942.²

Anti Shipping

As an anti shipping bomber the Blenheims sank 70 enemy ships from January to June 1941.²

Far East

There were four squadrons of Blenheims stationed in the Far East and suffered heavily when Japan invaded Malaya.³

Squadron Leader A Scarf of the 62 Squadron was awarded a posthumous Victoria Cross during these battles.³

Finland

Ten Blenheim Mk IVs were built under license.¹ The were used until 1956 in forestry and survey work.¹

Canada

Produced more than 600, known as the Bolingbroke.¹ Most were used as trainers for navigation and gunnery.¹ Some were fitted with ski gear for landing.¹ A few were used in reconnaissance over the Atlantic.¹

	Bristol Blenheim1	Bristol Blenheim Mk I3,5	Bristol Blenheim Mk IF3	Bristol Blenheim Mk IV1,2,5	Bristol Blenheim Mk IVF3	Bristol Blenheim Mk V3
Type		Bomber5, Light bomber3	Day fighter3, Heavy fighter5, Night fighter3	Bomber5, Light bomber1,2,3	Day fighter3 Night fighter3	Light bomber3
Crew		33,5		31,2,3,5 Pilot, navigator/observer, gunner1		33
Engine (Type)	2: Bristol Mercury VIII3	2: Bristol Mercury VIII5		2: Bristol Mercury XV piston1,2,3,5		2: Bristol Mercury 30s3
Cylinders	Radial 93	Radial 95		Radial2, Radial 93,5 , 91
Cooling		Air5		Air1,5
HP	840 each3	840 each5		905 each1, 920 each2,3,5		950 each3
Propeller blades	3 each3	3 each5		3 each3		3 each3
Dimensions
Span	56' 4"3 17.17 m3	56' 4"5		56' 4"2,3,5, 58' 4"1 17.17 m1,2,3
Length	39' 9"3 12.12 m3	39' 9"5		42' 7"1,2,3,5 12.98 m1,2,3
Height	9' 10"3 3 m3	9' 10"5		9' 10"1,2,3,5 2.99 m2, 3 m1,3
Wing area				469 ft2 1,2 43.57 m2 1,2
Weight
Empty			8,840 lb3 4,010 kg3	9,770 lb1, 9,790 lb2,3 4,441 kg1,2,3		11,000 lb3 4,990 kg3
Loaded		12,500 lb5	12,500 lb3 5,670 kg3	13,500 lb2,3,5, 14,370 lb1 6,124 kg2,3, 6,532 kg1		17,000 lb3 7,711 kg3
Performance
Speed @ 11,000'				266 mph5
Speed @ 11,500' / 3,505 m				266 mph3 428 kph3
Speed @ 11,800' / 3,595 m		260 mph5		265 mph1, 266 mph2 423 kph2, 428 kph1
Speed @ 15,000' / 4,572 m	278 mph3 447 kph3
Cruising speed	200 mph3 322 kph3
Climb	1,540'/minute3 469 m/minute3			1,500'/minute2,3 457 m/minute2,3
Service ceiling	25,500'3 7,772 m3	27,280'5		22,000'2,5, 24,6003, 27,250'1 6,705 m2, 7,500 m3, 8,310 m1
Range	1,050 miles3 1,690 km3	1,125 miles5		1,450 miles3, 1,460 miles1,2,5 2,333 km3, 2,350 km1,2
Armament				5: MG5 5: 7.7 mm MG1
Port engine		1: 0.303"3	1: 0.303"3
Port wing		1: Browning MG5		1: 0.303"3
Under fuselage tray			4: MG5 4: 0.303"3			2: 0.303"3
Ventral tray					4: 0.303"3
Nose				1: 7.7 mm MG2
Dorsal turret		1: 0.303"3 1: Vickers K MG5	1: 0.303"3	1: 0.303"3 2: 7.7 mm MG2		2: 0.303"3
Bombs		1,000 lb3,5 454 kg3		1,274 lb1, 1,320 lb3,5 579 kg1, 600 kg3		1,000 lb3 454 kg3
Bombs - internal				1,000 lb2 454 kg2
Bombs - external				320 lb2 145 kg2

Sources:

1. Aircraft of WWII, General Editor: Jim Winchester, 2004
2. Fighting Aircraft of World War II, Editor: Karen Leverington, 1995
3. Aircraft of WWII, Stewart Wilson, 1998
4. Blenheim Squadrons of World War 2, Jon Lake, 1998
5. World War II Airplanes Volume 1, Enzo Angelucci, Paolo Matricardi, 1976

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