British Power-Operated Gun Turrets

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Robert Hurst
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British Power-Operated Gun Turrets

#1

Post by Robert Hurst » 17 Apr 2003, 12:19

Hi

The A V Roe & Company Ltd

The Avro Wind-Vane Turret (Experimental)

Production of the Lancaster involved many man-hours installing hydraulic pipelines, recuperators, valves and various other services for the Parnall turrets. Although the turrets were efficient, it occurred to two Avro designers, C B Redrup and G Beardsall, that weight and labour could be saved if a simpler self-contained system could be devised.

They designed a mock-up using the force of the slipstream, an idea similar to the one used by Barnes Wallis for the Vickers G.4/31 biplane. The power source was a retractable wind-vane motor, at the top of the turret, which drove a hydraulic pump. When the pump was working oil was drawn from a reservoir in the base of the turret. The oil then passed through the operator's control valves, motivating a hydraulic rotation motor and a ram which elevated or depressed the guns. When not in use the motor could be retracted.

In 1941 a patent was applied for in the name of the two designers and A V Roe Ltd. The specification mentioned a possible alternative of an electrical drive, driven by a slipstream-operated generator. It is difficult to believe how such a system could have provided enough power to drive a heavy turret against the slipstream, but if this could have been achieved it would have been an equally compact and simple system.

No records exist of any serious development programme. The round-the-clock production of the Lancaster, and the fact that the specialist turret companies were fully extended with new designs, would have decided the Air Staff against such a scheme.

The Boulton Paul Aircraft Ltd

The Boulton Paul Type A Series - Pt 1

The Type A turret was almost identical in appearance to the prototype produced in France by SAMM. The first aircraft to be fitted with the new turret was the Boulton Paul Overstrand, in which the initial air firing tests were carried out using Browning guns in place of the French Darne guns originally fitted. Several modifications and additions were incorporated in the production version, including the drum-type fire interrupter gear and modified control system. As mentioned previously the Boulton Paul Defiant was designed around the Type A turret and the first production model was known as the Type A Mk IID, the 'D' referring to the Defiant to distinguish it from the slightly different model fitted to the Blackburn Roc naval fighter. A novel feature of both installations was the retractable fairing system. The front and rear turret fairings were held in the 'Up' position by pneumatic rams supplied from a bottle in the fuselage. When the guns approached one of the fairings an air valve was closed and it dropped into the 'Down' position, allowing the guns to be traversed past it.

During its first wartime sorties the Defiant accounted for 37 Luftwaffe aircraft in a few days, but when its weaknesses - lack of speed and manoeuvrability - were laid bare it suffered the same fate as most two-seat fighters and was relegated to night intereception duties.

The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
Defiant turret fairings.jpg
Defiant turret fairings.jpg (35.95 KiB) Viewed 6598 times
A V Roe wind vane powered turret.jpg
A V Roe wind vane powered turret.jpg (32.82 KiB) Viewed 6598 times
Defiant night fighter.jpg
Defiant night fighter.jpg (28.08 KiB) Viewed 6598 times
Last edited by Robert Hurst on 02 May 2003, 11:41, edited 5 times in total.

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#2

Post by Robert Hurst » 22 Apr 2003, 11:30

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Type A Series - Pt 2

The Type A Mk. IID proved an efficient design, its low profile causing a minimum of drag to the aircraft. The Hele-Shaw-Beacham hydraulic variable gear system provided a very smooth operating movement in both traverse and elevation. The gunner's view was not ideal, being impeded by the guns and feed mechanism, but he had a reasonable view to his front and directly to each beam. The four Browning guns were mounted in pairs on either side of the turret, while to the gunner's front was the control table with the following operating equipment.

This control had two positions. When pulled to the rear 'Free' position the rotation drive was disconnected mechanically and the connections to the hydraulic elevation rams short-circuited through a bypass valve. When pushed forward to the 'Engaged' position, the turret was operational.

The gun master switch was a three-position switch marked PILOT, OFF, GUNNER. The PILOT position was never used and was disconnected, being in effect another OFF position; when the GUNNER position was selected the gun firing circuit was alive.

The control column - 'joystick' - was on the right of the control table projecting through a diamond-shaped aperture. Movement of the column controlled the output from the hydraulic generator, and thus the speed and direction of elevation and rotation. A grip lever on the column energised the elecrtic-motor armature when grasped, and a gun-firing button on the top of the column was operated by the gunner's thumb.

On the right of the control panel over the gun switch was the motor main switch, which when closed energised the field of the motor and was indicated by a red warning lamp. The turret could then be operated from the control column.

In the centre of the table was a red button. When this was pressed it connected a resistance in series with the motor field winding, which doubled the speed of the motor and enabled the gunner to change quickly from one target to another. The button was used only for short periods as it imposed an overload on the motor and hydraulic system.

If the power system failed the turret could be operated by a hand rotation mechanism. A small handle was stowed under the right armrest. This was fitted to a gear shaft and, with the disengaging lever to FREE, the turret could be rotated. It was also just possible to elevate the guns by pressing the back end of the breeches.

The four Browning Mk.II guns were mounted on their sides with the cocking levers upper-most: they were cocked by the usual looped lanyard. Four 600-round ammunition boxes were fixed in front of the gunner's legs, the ammunition belts being lifted from the boxes by the gun feed mechanism over 90 degree chutes. Spent cartridges and links were collected in collapsible bags below the guns. The guns were fired by electrical solenoid sear-release units; the gun button operated a relay which energised the releases. Sighting was by a Mk.IIIA reflector sight mounted on an arm which moved in unison with the guns, the sight switch being on the left of the control table. An adjustable floodlight controlled from a switch under the sight switch enabled the gunner to clear stoppages on night operations.

The above text and top photo were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke. The bottom photo was taken from "Armament of British Aircraft 1909-1939", by H F King.

Regards

Bob
Attachments
Interior of Defiant turret.jpg
Interior of Defiant turret.jpg (55.69 KiB) Viewed 6585 times
Type A turret operating procedure.jpg
Type A turret operating procedure.jpg (55.07 KiB) Viewed 6586 times
Last edited by Robert Hurst on 02 May 2003, 11:42, edited 3 times in total.


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#3

Post by Robert Hurst » 22 Apr 2003, 11:46

Hi

The Boulton Paul Aircraft Ltd

The Type A Mk.VIII

Handley Page selected Boulton Paul turrets to arm the Halifax bomber. The first production aircraft (the Mk.I) had nose and tail turrets, and the Mk.II was also fitted with the bulbous Type C turret in the mid-upper position. However, to help improve performance this was discontinued, and from the Series IA onwards a modified Type A four-gun turret was used, the Mk.VIII.

The Mk.VIII was first mounted on a raised surround with a contour track for a mechanical interrupter gear, but on the Halifax B.Mk.II Series IA the turret was lowered 127 mm (5 in) and fitted with a simple skirt fairing. Trouble was also experienced with the interrupter gear and the Boulton Paul drum-type system was refitted.

Another modification was the deletion of the sliding double doors at the back of the turret. The doors were originally fitted to provide an escape exit on the Defiant and were retained on the early Mk.VIII models. It was after many reports such as Sgt. Les Fuller's that the doors were deleted.

Several times on operations they whipped open with a hell of a roar and bang, the slipstream ripped in and almost dragged you out of the turret. It was terrifying when it happened, and it was almost impossible to close them as I was tall and there was little elbow room. The trouble was caused by the retaining studs being forced out of the runners by the slipstream.

Details of the Type A Turret

Position in aircraft: Mid-upper & tail
Motive power: BP electro-hydraulic system
Armament: Four 7.7 mm Browning Mk.II guns
Fire control: Magnavox 24 v solenoid sear-release units
Field of fire:
Traverse: 360 degrees
Elevation: 0-84 degrees
Depression: Nil
Gunsight: Mk.IIIA reflector sight
Weight empty: 170 kg (373 lb)
Weight armed: 282 kg (621 lb)
Speed of operation:
Normal: 24 degrees/sec (motor 3,000 rpm)
High speed: 48 degrees/sec (motor 5,400 rpm)
Armour protection:
early models: 9 mm (0.354 in) face visor
Later models: 9 mm (0.354 in) armoured apron surrounding turret body
Ammuntion: 600 rounds per gun in boxes within turret
Gunfire protection: Interrupter: cylinder type with following brushes

The following aircraft were fitted with the Type A turret.

Aircraft type: Boulton Paul Defiant F.Mk.I, N F.Mk.IA & N.F.Mk.II
Type & Mark: A.Mk.IID
Position: Mid-upper
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 84 degrees
Depression: 0 degrees
Status: Series production

Aircraft type: Blackburn Roc
Type & Mark: A.Mk.IIR
Position: Mid-upper
Guns: 4 x 7.7 mm (0.303 in)
Traverse: 360 degrees
Elevation: 84 degrees
Depression: 0 degrees
Status: Series production

Aircraft type: Short 'C' Class (S.23M) Flying boat
Type & Mark: A.Mk.II
Position: Mid-upper & tail
Guns:
Mid-upper: 4 x 7.7 mm (0.303 in) Browning Mk.II
Tail: as above
Traverse:
Mid-upper: 360 degrees
Tail: 180 degrees
Elevation:
Mid-upper: 84 degrees
Tail: 74 degrees
depression:
Mid-upper: 0 degrees
Tail: 10 degrees
Status: 2 only

Aircraft type: Short 'G' Class (S.26M) Flying boat
Type & Mark: A.Mk.II
Position: Mid-upper (2), tail
Guns:
Mid-upper: 4 x 7.7 mm (0.303 in) Browning Mk.II
Tail: as above
Traverse:
Mid-upper: 360 degrees
Tail: 180 degrees
Elevation:
Mid-upper: 84 degrees
Tail: 74 degrees
Depression:
Mid-upper: 0 degrees
Tail: 10 degrees
Status: three only

Aircraft type: Armstrong Whitworth Albemarle Mk.I
Type & Mark: A.Mk.III
Position: Mid-upper
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 84 degrees
Depression: 0 degrees
Status: Series production

Aircraft type: Consolidated B-24C Liberator B.Mk.II*
Type & Mark: A.Mk.IV
Position: Mid-upper
Guns: 4 x 7.7 mm Browning Mk.II
Traverse: 360 degrees
Elevation: 84 degrees
Depression: 0 degrees
Status: Series production

Aircraft type: Lockheed Ventura B.Mk.II*
Type & Mark: A.Mk.V
Position: Mid-upper
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 74 degrees
Depression: 10 degrees
Status: Series production

Aircraft Type: Martin Baltimore B.Mk.III
Type & Mark: A.Mk.VA
Position: Mid-upper
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 74 degrees
Depression: 10 degrees
Status: Series production

Aircraft Type: Handley Page Halifax B.Mk.II Series IA, B.Mk.III, B.Mk.V, B.Mk.VI & B.Mk.VII*
Type & Mark: A.Mk.VIII
Position: Mid-upper
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 74 degrees
Depression: 2 1/2 degrees
Status: Series production

Aircraft type: Bristol Beaufighter Mk.V
Type & Mark:
Position: Behind pilots cockpit
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse:
Elevation:
Depression:
Status: One only. Experimental

* Denotes aircraft used by both Bomber and Coastal Commands during the war.

The above text was taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

The top photo was taken from "The British Bomber since 1914", by Peter Lewis. The middle photo was taken from "Aircraft of the Royal Air Force since 1918", by Owen Thetford. The bottom photo was taken from "The Hamlyn Guide to British Aircraft of World War II", by David Monley.

Regards

Bob
Attachments
Armstrong Whitworth Albemarle B.Mk.I.jpg
The Albemarle B.Mk.I was fitted with the A.Mk.III turret.
Armstrong Whitworth Albemarle B.Mk.I.jpg (33.06 KiB) Viewed 6564 times
Consolidated Liberator B.Mk.II.jpg
The Consolidated Liberator B.Mk.II was fitted with the A.Mk.IV turret.
Consolidated Liberator B.Mk.II.jpg (26.85 KiB) Viewed 6564 times
Handley Page  Halifax B.Mk.III.jpg
The Handley Page Halifax B.Mk.III was fitted with the A.Mk.VIII turret.
Handley Page Halifax B.Mk.III.jpg (38.74 KiB) Viewed 6564 times
Last edited by Robert Hurst on 02 May 2003, 11:43, edited 4 times in total.

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#4

Post by Robert Hurst » 23 Apr 2003, 11:06

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Type C Mk.I Nose Turret

The Boulton Paul Type C nose turret was one of the three new turret designs chosen by Handley Page Ltd to arm the HP 57 four-engined bomber, the Halifax. The Type C was tailored to fit the front fuselage, being armed with two 7.7 mm (0.303 in) Browning guns. The turret was mounted over the bomb aimer'sposition, but both crewmen could operate together without problem.

The turret was powered with the standard BP electro-hydraulic system, the power unit being fitted to the front lower part of the chassis. Low to each side of the seated gunner were the ammunition boxes containing 1,000 rounds for each gun. the gunner stepped into his position from the navigator's place, the adjustable seat giving him a good view of the Mk.IIIA reflector sight, mounted on a single arm and linked to the elevation movement of the guns. He sat high in the cupola with a good field of view, with all control switches and fuseboxes etc. mounted within easy reach, while bulkheads on the side supported the Perspex cupola framing. In the event of a power failure the turret could be turned by a handle after the hydraulic motor was disengaged. The guns were mounted on their sides with the cocking studs uppermost, the ammunition belts being drawn through apertures in the gun trunnions by way of rollers from the ammunition boxes below.

As mentioned earlier, during initial air testing severe vibration was encountered in the forward airframe of the Halifax, which after investigation was found to be due to turbulence set up by the nose turret -when turned to a beam position the pilot had difficulty in controlling the aircraft. The situation was made worse when it was found that the air drag prevented the turret from being centralised. Various modifications were carried out, including the fitting of balance flaps operated by cams, which automatically extended into the airstream on the opposite side to the guns. Pilots reported that although this improved matters there was still a considerable yawing movement, which could not be entirely trimmed out when the turret was turned.

The C Mk.I turret was not used a great deal on operations. It gave protection in daylight sorties against head-on attacks, but its main use was just the fact that it was there, to deter attacking fighters whio usually made their approach from a position where defensive fire was weakest.

The top photo was taken from "Aircraft of the Royal Air Force since 1918", by Owen Thetford. The middle photos were taken from "The British Bomber since 1914", by Peter Lewis & the bottom photo was taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

The above text was taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
Type C.Mk.I turret.jpg
Type C.Mk.I turret.jpg (48.82 KiB) Viewed 6541 times
Handley Page Halifax.jpg
Handley Page Halifax.jpg (43.03 KiB) Viewed 6541 times
Handley Page Halifax Mk.I.jpg
Handley Page Halifax Mk.I.jpg (20.58 KiB) Viewed 6541 times
Last edited by Robert Hurst on 02 May 2003, 11:43, edited 4 times in total.

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#5

Post by Robert Hurst » 23 Apr 2003, 14:33

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Type C Mk. II Mid-upper Turret

The Air Staff expected great things of the Lockheed Hudson once an agreement had been reached with the USA to supply this bomber in 1938. They were to be shipped unarmed, all armament and bomb gear being fitted in the UK. It was decided to install a mid-upper turret and a fixed forward-firing Browning gun aimed by the pilot.

Boulton Paul were asked to submit a turret design suitable for the aircraft. At this time (1938) the production of the four-gun Type A turret was urgently needed for the Defiant, which it was hoped would be the scourge of hostile bomber aircraft. As the Halifax nose turret was approaching the production stage, someone suggested that if a rear section could be added to it to accommodate the gunner it would make a very roomy mid-upper turret. Drawings were made and submitted to the Air Ministry. where the Air Staff were only too pleased to accept the design and issued an order for three prototypes, and a mock-up fitted to a Hudson fuselage.

The first prototype took only nine weeks to complete, since it was merely a matter of adding a rear section aerodynamically similar to the Mk.I, the Perspex framing being supported by the heavy back section of the front turret. This was also used to support the electrical power and sight switches, inspection lamps and fuse boxes. Provision was made for a full 360 degrees traverse, and the new turrets, known as the Type C.Mk.II, were tailored to fit the ample rear fuselage of the Hudson aircraft.

The first operational RAF squadron to be equipped with Hudsons was No.224, just before the outbreak of war. The initial order for 200 was increased to 2,000 until 27 squadrons flew them. Their prime role was with Coastal Command where the ample proportions of the Type C.Mk.II turret gave the gunner an ideal look-out position for the long sea searches involved. The turret was also fitted to the first versions of the Lockheed Ventura. A development of the Hudson, this aircraft was used by three squadrons of No.2 Group for daylight bombing, but proved unsuitable and was also seconded to maritime reconnaissance.

On 8 October 1939 an air gunner of No.224 squadron directed an accurate burst of fire into a Dornier Do 18 flying-boat over the North Sea. The gunner was manning a Hudson turret, and when the flying-boat hit the water it was the first German aircraft to be destroyed by a UK-based aircraft in the Second World War.

The first operational Halifaxes were protected from beam attacks by pillar-mounted twin Vickers GO guns firing from hatches in the fuselage sides. These aircraft were used in daylight attacks on German ships in the harbour at Brest, from where combat reports suggested that a mid-upper turret would improve defensive armament. The ideal choice would have been the four-gun Type A, but for some reason it was decided to use the C.Mk.II. This gave the B.Mk.II Halifaxes improved defence in the beam and overhead zone, but reduced the speed of the aircraft by 9.7kph (6 mph). When Halifaxes turned to night operations attacks from these sectors were very rare, and when in the B.Mk.II Series I (Special) the fuselage was modified to improve performance, both the nose and mid-upper turrets were dispensed with. Gunnery leaders of No.4 Group soon made it known that they were not happy with single-turret Halifaxes operating over Germany. The point was taken, and when the Series IA Halifaxes appeared they came armed with a new Type A four-gun mid-upper turret, the A.Mk.VIII.

Details of the C.Mks I and II Turrets

Position in aircraft:
C.Mk.I: Nose
C.Mk. II: Mid-upper
Power system: BP electro-hydraulic
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 1,000 rounds per gun
Gun firing gear: 24 v electrical solenoid sear-release
Field of fire: C.Mk.I
Traverse: 100 degrees either beam
Elevation: 60 degrees
Depression: 45 degrees
Field of fire: C.Mk.II
Traverse: 360 degrees
Elevation: 60 degrees
Depression: 10 degrees
Speed of operation:
Normal: 24 degrees/sec
High speed: 48 degrees/sec
Gunsight: Mk.IIIA reflector sight
weight empty: 180 kg (396 lb)
Weight armed: 261 kg (575 lb)
Electrical power: 24 v motor from 1,000 watt generator

The following aircraft were fitted with the Type C.Mk.I Turret

Aircraft type: Handley Page Halifax B.Mk.I & B.Mk.II
Type & Mark: C.Mk.I
Position: Nose
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 100 degrees either beam
Elevation: 60 degrees
Depression: 45 degrees
Status: Series production

The following aircraft were fitted with the Type C.Mk.II Turret

Aircraft type: Lockheed Hudson G.R.Mk.1
Type & Mark: C.Mk.II
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 60 degrees
Depression: 45 degrees
Status: Series production

Aircraft type: Lockheed Hudson G.R.Mk.II, G.R.Mk.III, G.R.Mk.IIIA, G.R.Mk.IV, G.R.Mk.V & G.R.Mk.VI
Type & Mark: C.Mk.IIA
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 60 degrees
Depression: 45 degrees
Status: Series production

Aircraft type: Lockheed Ventura B.Mk.I
Type & Mark: C.Mk.IV
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 60 degrees
Depression: 45 degrees
Status: Series production

Aircraft type: Handley Page Halifax B.Mk.II
Type & Mark: C.Mk.V
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 60 degrees
Depression: 30 degrees
Status: Series production

The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
Cutaway of Type C Series turrets.jpg
Cutaway of Type C Series turrets.jpg (48.93 KiB) Viewed 6537 times
BP C.Mk.II turret.jpg
BP C.Mk.II turret.jpg (39.07 KiB) Viewed 6537 times
BP Type C.Mk.V turret.jpg
BP Type C.Mk.V turret.jpg (32.03 KiB) Viewed 6539 times
Last edited by Robert Hurst on 02 May 2003, 11:44, edited 4 times in total.

Caldric
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#6

Post by Caldric » 23 Apr 2003, 17:31

Good information thanks.

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#7

Post by Korbius » 23 Apr 2003, 22:14

Too bad it was missing forward firing MG's, making it vulnerable to frontal attacks.

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lisset
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RAF Powered Turrets.

#8

Post by lisset » 24 Apr 2003, 09:33

Robert, have you been to the Air Gunners room at Elvington ?
They have a number of turrets set up in excellent order allowing visiots a 360 degree look around each along with a mass of information relaing to the Air Gunners trade.
Its well worth a visit.
My late uncle was an air gunner with Bomber Command , the enteries in his logbook relating to training and gunnery exercies are quite interesting.
A much neglected subject.

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#9

Post by Robert Hurst » 24 Apr 2003, 10:42

Hi Isset

No. I haven't been to the Air Gunners Room at Elvington, but from what you say I hope to visit it sometime in the not too distant future.

I would be very interested in learning something about your late uncles experiences as a Bomber Command air gunner.

Regards

Bob

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Robert Hurst
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#10

Post by Robert Hurst » 24 Apr 2003, 11:42

Hi

The following aerial photos were taken from: Top: "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke. Centre: "Aircraft of the Royal Air Force since 1918", by Owen Thetford and bottom: "The Hamlyn Guide to British Aircraft of World War II", by David Mondey.

Regards

Bob
Attachments
Lockheed Ventura with BP Type C.Mk.II turret.jpg
Lockheed Ventura with BP Type C.Mk.II turret.jpg (29.42 KiB) Viewed 6534 times
Handley Page Halifax II with Type C.Mk.II turret.jpg
Handley Page Halifax II with Type C.Mk.II turret.jpg (20.59 KiB) Viewed 6534 times
Lockheed Hudson Mk.I with Type C.Mk.II turret.jpg
Lockheed Hudson Mk.I with Type C.Mk.II turret.jpg (23.62 KiB) Viewed 6535 times

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#11

Post by Robert Hurst » 24 Apr 2003, 12:00

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Type E Tail Defence Turret - Pt 1

The Boulton Paul Type E provided rear defence for RAF Halifax and Liberator II aircraft, and proved to be one of the most successful turrets ever produced. Unlike other Boulton Paul designs, it was not particularly roomy, but ex-gunners recall how the turret seemed to be tailored to fit, with little wasted space.

To the gunner's front was the control table with the operating stick protruding through the centre. Above the table was a fascia panel with the main motor switch, sight switch and oxygen supply socket facing the gunner. Two armrests were provided which were lowered into position when the gunner was seated, giving support and enabling him to control the operating handle accurately. Directly to his front was a Mk.IIIA reflector sight fixed to an arm which was carried in bearings, and connected to the gun arms by a connecting rod.

Below the sight was a 9 mm (0.354 in) armoured visor fixed on a frame which moved in elevation with the sight, providing frontal protection - some gunners had the armour removed to provide a better field of view. All-round visibility was adequate, although the rear downward view was somewhat restricted by the guns and controls but this was partly overcome by a feature which had first been used on the Overstrand front turret. When the guns were depressed, two small hydraulic rams raised the seat, keeping the gunner's line of sight parallel with the gun barrels and giving a good view downwards when searching. This feature was reluctantly praised by dyed-in-the-wool Frazer-Nash enthusiasts, the seat in FN turrets being fixed so that for high elevation firing the gunner had to crouch forward.

Another very useful feature of the Boulton Paul system was the high-speed facility described in the Type A section. When the red high-speed button on the control table was pressed, rotation and elevation controls were speeded up for rapid changes of target.

The turret was powered by the usual Boulton Paul electro hydraulic stystem, all the operating mechanisms being fixed out of sight under the control table at the front of the cupola, providing added protection for the operator.

The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
Gun servicing panels.jpg
Gun servicing panels.jpg (42.53 KiB) Viewed 6526 times
Handley Page Halifax with BP Type E turret.jpg
Handley Page Halifax with BP Type E turret.jpg (31.43 KiB) Viewed 6526 times
Power Operation of Turret.jpg
Power Operation of Turret.jpg (37.37 KiB) Viewed 6527 times
Last edited by Robert Hurst on 02 May 2003, 11:44, edited 3 times in total.

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#12

Post by Robert Hurst » 25 Apr 2003, 10:19

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Type E Tail Defence Turret - Pt 2

The four 7.7 mm (0.303 in) Browning Mk.II guns were mounted on their sides in pairs on either side of the gunner, with the cocking handles uppermost and within easy reach for stoppage clearance. Each gun was provided with 2,500 rounds of ammuntion, to a total weight of 295 kg (650 lb), and to assist in fore and aft trim, the ammunition boxes were fixed on the port side of the fuselage, well forward and remote from the turret. On the first few production Halifaxes the ammunition was routed from the boxes along plastic chutes to the base of the turrets, but after trouble with distortion and belt jamming these were changed to chromium-plated tracks. The four belts were led through the base of the turret via special linkages, which allowed the belts to twist through 90 degrees to allow for rotation.

Initial trials of the turret revealed that the gun feed mechanisms were unable to pull the long belts from the remote boxes, and an ingenious ammunition servo feed assister was fitted. Although quite heavy, the assister proved very efficient, and luckily for the service armourers, the complicated mechanism rarely gave tropuble. The belts were fed through toothed sprockets which were attached to hinged arms - when the belts were under tension the arms moved over, and this engaged a band clutch which applied power to the sprockets. The system was very smooth in operation, and tended to overfeed the gun feed units, lessening the chance of stoppages. In the event of a stoppage in one of the guns, the assister automatically stopped the belt feeding the jammed gun. From the assister the belts were guided over rollers through right-angled chutes into the gun feeds, empty cases and links being ejected through slots into the slipstream. The guns were fired by a button on the top of the control handle. This closed an electrical relay which activated gun-firing solenoids mounted under the gun bodies.

The gunner entered the turret through double doors after clipping his parachute to a rack just outside in the fuselage. After taking his seat and fastening his wide canvas safety strap, he lowered the two armrests into position. He then plugged in his oxygen and intercom jack and checked that the drive-motor lever was in the engaged position - this was low and to his left side. His guns were now cocked, and with the 'fire and safe' control set to 'fire', he then turned on the gun-firing master switch and sight switch. At this point the main motor armature switch was switched on and a red indicator light showed that the turret was operational. The gunner then grasped the lever on his controller, which started the drive motor, and tested the turret for elevation and rotation. In the event of a power failure, the turret could be turned by hand. To do this the disengaging lever was operated, then a handle mounted low and to the gunner's right side was turned. This engaged a pinion into the gear teeth of the turet ring, and turned the turret in either direction.

The Type E was popular with the gunners, and was fitted to all Halifax aircraft until the introduction of the Type D turret armed with 12.7 mm (0.5 in) Browning guns. When the American Liberator II bombers arrived they were unarmed, but had been prepared for the fitting of Boulton Paul Type A mid-upper and Type E tail turrets. These were fitted to the first British order of 140 aircraft, which had been built with deepened and lengthened fuselages to accommodate the Type E rear turret installation. Over 8,000 Type E turrets were produced, the majority by the Lucas Company, and many German fighters fell tot he guns of this excellent design.

Details of the Boulton Paul Type E Mks. I , II and III

Position in aircraft: Tail
Power system: Electro hydraulic
Armament: Four 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 2,500 rounds per gun
Field of fire:
Traverse: 65 degrees either side
Elevation: 60 degrees
Depression: 50 degrees
Weight empty: 309 kg (403 lb)
Weight armed : 308 kg (679 lb)
Gunsight: Mk.IIIA reflector gunsight

Mk.I: First production batch
Mk.II: Modfied controls and elevation of 56.5 degrees
Mk.III: Fitted to Liberator and later Halifaxes

The following aircraft were fitted with the Boulton Paul Type E Mks.I, II and III

Aircraft types: Handley Page Halifax B.Mk.I, B.Mk.II, B.Mk.III, B.Mk.V & B.Mk.VI, Consolidated Liberator B.Mk.II
Type & Mark:
Type E Mk.I & II: early Halifaxes
Type E Mk.III: Consolidated Liberator Mk.II & later Halifaxes
Positon: Tail
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse:
E Mk.I & II: 180 degrees
E.Mk.III: 130 degrees
Elevation:
E.Mk.I: 60 degrees
E.Mk.II: 56.5 degrees
E.Mk.III: 60 degrees
Depression: 50 degrees
Status: Series production

The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Guns and Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
BP Type E electrical distributor & ammo ducts.jpg
BP Type E electrical distributor & ammo ducts.jpg (58.43 KiB) Viewed 6513 times
Consolidated Liberator Mk.II fitted with Type E turret.jpg
Consolidated Liberator Mk.II fitted with Type E turret.jpg (25.36 KiB) Viewed 6511 times
Type E sight linkage system.jpg
Type E sight linkage system.jpg (29.59 KiB) Viewed 6513 times
Last edited by Robert Hurst on 02 May 2003, 11:45, edited 4 times in total.

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Robert Hurst
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#13

Post by Robert Hurst » 25 Apr 2003, 14:34

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Type K Ventral Turret

In common with most other manufacturers, Handley Page made provision for an under defence turret on the Halifax. Boulton Paul submitted a design for a compact turret mounting two Browning guns. The gunner sat in a seat and controlled the guns by means of a small joystick, his only view of the approach of a fighter being through a wide-angle periscopic sight. Whereas a tank gunner could zero on to a ground target with such a sighting system, the air gunner usually has only a few seconds to aim and fire at an attacking fighter. The turret was a very efficient unit, having full 360 degrees traverse and sufficient depression and speed of operation, but as with almost every other ventral turret with periscopic sights, gunners just could not find such fast-moving targets.

The production line was stopped after 27 turrets were made because adverse reports were received from the first squadrons equipped with the Halifax, and the turrets already in use were taken out by squadron armourers. Some squadrons fitted hand-held guns firing through hatches cut in the fuselage floor. The most effective of these simple under defence positions was the Preston Green mounting which was used by several squadrons.

Details of the Type K Mks. I & II Turrets

Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 500 rounds per gun
Power unit: BP electro-hydraulic system
Field of fire:
Traverse: 360 degrees
Elevation: 0 degrees
Depression: K.Mk. I 60 degrees; K.Mk.II 90 degrees
Gunsight: Wide angle periscopic sight

The following aircraft were fitted with the Boulton Paul Type K Mks. I & II turrets.

Aircraft type: Handley Page Halifax B.Mk.I & Armstrong Whitworth Albemarle B.Mk.I
Type & Marks: K.Mk.I Handley Page Halifax; K.Mk.II: Armstrong Whitworth Albemarle
Position: Mid-under
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: Both 360 degrees
Elevation: Both 0 degrees
Depression: Mk.I 60 degrees; Mk.II 90 degrees
Status: Both early production only

A later under defence turret envisaged by Boulton Paul was the Type R.

The only information with regards to the Type R is as follows:

Aircraft type: Handley Page Halifax
Type & Mark: R Mk.II
Position: Mid-under
Guns: 2 x 7.7 mm(0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation:
Depression: 70 degrees
Status: Experimental

The above text and photo was taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
Type K under defence turret.jpg
Type K under defence turret.jpg (23.38 KiB) Viewed 6508 times
Last edited by Robert Hurst on 02 May 2003, 11:46, edited 3 times in total.

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Robert Hurst
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#14

Post by Robert Hurst » 25 Apr 2003, 15:05

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Types S, T, U and V Turrets Pt - 1

In late 1939 it was decided to modify the BP Types A, E & F to enable American 12.7 mm (0.5 in) Browning guns to be fitted. It was thought that this would improve the range and hitting power of RAF bomber turrets. The new turrets were designated the Type S (tail), Type T (dorsal), Type U (ventral) and Type V (nose). It was unfortunate that at the time the first two prototypes were completed and sent for trials, the RAF was frantically trying to build-up the strength of Bomber Command. Lord Beaverbrook was the overlord of all aircraft production, and he insisted that the companies involved in the vital production of the new type of bombers, just coming on stream, should not introduce any new equipment which could hold back production. The Stirling, Manchester and Halifax 7.7 mm (0.303 in) turrets were in full production, and the aircraft had all been designed to take the elaborate pipelines and electrical services of the rifle-calibre turrets. To introduce completely new and untried turrets would certainly have held back production, and the big Brownings would have had to have been purchased from America, as there were no facilities to produce them in the UK. What probably sealed the fate of the big gun turrets of Boulton Paul, Bristol and Parnall was the fact that the Air Staff reasoned that with the switch to night operations the extra range of the heavy Brownings would be of limited use, as night fighters were usually engaged at 275-366 m (300-400 yds) in the skies over Germany. Also, a four-second burst from four 7.7 mm (0.303 in) Brownings sent a cone of 300 rounds towards a would-be attacker, as against 96 from a two-gun 12.7 mm (0.5 in) turret. Boulton Paul, Parnall, and Bristol heavy calibre armed turrets could perhaps have been ready for operational use in 1940-41, but the decision to cancel further development at that time was probably sound in view of the critical situation which then existed.

However, the Boulton Paul turrets incorporated several new features. The gun trunnions were strengthened, and a completely new ammunition feed system was introduced. Another and potentially significant development was the fact that the turrets were designed to use the highly secret Mk.I gyro gunsight.

The Text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
BP Type T and Type S turrets.jpg
BP Type T and Type S turrets.jpg (17.64 KiB) Viewed 6496 times
Last edited by Robert Hurst on 02 May 2003, 11:47, edited 2 times in total.

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#15

Post by Robert Hurst » 26 Apr 2003, 09:59

Hi

The Boulton Paul Aircraft Ltd

The Boulton Paul Types S, T, U and V Turrets Pt - 2

The Type S tail turret was found to vibrate excessively when fired, and needed modification to the gun mountings. The ventral and nose turrets were not fully developed, but the dorsal Type T was found to be very promising. When the prototypes were being tested at Pendeford Lane a party of American Army Air Corps officers visited the factory and showed interest in all the turrets being produced by the company. They spent some time looking over the 12.7 mm (0.5 in) turrets and mentioned to the RAF Liaison Officer that they were just beginning to issue development contracts for powered turrets. The Americans had been very slow to adopt turret armament for their aircraft, most of the current Army Air Corps types being armed with hand operated gun positions.

At this time Britain was receiving an increasing amount of vital armaments from America, and when the final cancellation of work on all 12.7 mm (0.5 in) turrets came through, the company was told to crate the completed turrets for shipment to Wright Field, Ohio. Representitives of companies engaged in the design of the first US power turrets were invited to use any of the various systems and control details that the experienced Boulton Paul turret team had developed.

The American engineers made a detailed study of the BP turrets and also some Parnall turrets which had been despatched to Wright Field. There is no doubt that various features were used by the American designers in fact, a study of the early Sperry mid-upper turret used on the B-17E Flying Fortress shows a remarkable similarity to the Boulton Paul Type T turret. As will be seen in the American turret section (to be dealt with separately), the powered turrets produced by these companies were excellent designs, and as new aircraft designs multiplied the number and variety of units manufactured reached almost unbelievable quantities.

No records seem to have survived of the technical details of the Type S and T, and as mentioned before the U and V prototypes were not completed. They were some of the many turrets and other experimental items produced during those hectic days which were not proceeded with as priorities changed.

Summary of Boulton Paul Types S, T, U and V Turrets

Aircraft type: Not allocated
Type & Mark: S.Mk.I
Position: Tail
Guns: 2 x 12.7 mm (0.5 in) Browning Mk.II
Traverse: 180 degrees
Elevation: 60 degrees
Depression: 45 degrees
Status: Experimental

Aircraft type: Not allocated
Type & Mark: T.Mk.I
Position: Mid-upper
Guns: 2 x 12.7 mm (0.5 In) Browning Mk.II
Traverse: 360 degrees
Elevation: 60 degrees
Depression: 0 degrees
Status: Experimental

Aircraft type: Not allocated
Type & Mark: U.Mk.I
Position: Mid-under
Guns: 2 x 12.7 mm (0.5 in) Browning Mk.II
Traverse: 180 degrees
Elevation: 0 degrees
Depression: 60 degrees
Status: Experimental

Aircraft type: Not allocated
Type & Mark: V.Mk.I
Position: Nose
Guns: 2 x 12.7 mm (0.5 in) Browning Mk.II
Traverse: 120 degrees
Elevation: 45 degrees
Depression: 45 degrees
Status: Experimental

The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.

Regards

Bob
Attachments
Early Sperry mid-upper turret.jpg
Early Sperry mid-upper turret.jpg (56.01 KiB) Viewed 6485 times
BP Type T turret.jpg
BP Type T turret.jpg (21.91 KiB) Viewed 6486 times
Last edited by Robert Hurst on 02 May 2003, 11:48, edited 2 times in total.

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