Hi
The Nash and Thompson Engineering Company - Pt 4
The Nash and Thompson Type FN.4 Rear Turret - Pt 2
When the four Brownings were fired, cordite fumes would rapidly spread along the fuselage to the other crew positions, and prolonged firing resulted in a heavy build-up of gases in the turret. Ventilators were fitted in the top of the Perspex cupola, but the problem was not fully overcome until an open direct vision panel was fitted to aid sighting. In the event of a gunner being injured with the turret turned to a beam position, it was possible for another crew member to turn the turret from inside the fuselage. A lever outside the turret operated the rotation valve, and the doors could then be opened to assist the wounded gunner.
Seated in his position at the extreme end of the fuselage, the gunner felt completely isolated in mid-air: he could not see any other part of the aircraft unless he traversed to one side, and several gunners have mentioned the feeling of hurtling across the sky completely alone. In early models, when the turret was turned sideways the slipstream pressure on the guns affected the aircraft's trim. Pilots reported a marked effect on the controls when the gunner turned his turret. The trim was eased when two balancing aerofoils were fitted: when the turret was turned an aerofoil extended on the side opposite to the guns.
The FN.4 was first used operationally in the Whitley Mk.IV, and during one of the first night leaflet raids a damaged Whitley made a forced landing in Germany. The aircraft was repaired and the turret was evaluated by Luftwaffe armament experts. Their assessment was very complimentary regarding the fire power of the four Brownings, and they also reported favourable on the hydraulic controls. It was noted that accuracy of fire was affected by any evading manoeuvres and sudden acceleration. The FN.4 was at that time the most heavily armed turret in service with any Air Force, with a rate of fire of 4,800 rounds per minute, or 80 rounds per second. The turret gave the RAF bombers a real chance of success against attacking fighters. The relative short range of the 7.7 mm (0.303 in) calibre guns was not considered critical, as most engagements at night were carried out at short range. The FN.4 was also fitted to the Lerwick, Manchester, early models of the Stirling, and the Wellington Mk.III.
Details of the Nash and Thompson FN.4 Rear Turret
Position: Tail
Armament: Four 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 1,000 rounds per gun, stored in turret
Gunsight: Mk.IIIA reflector sight
Motive power: Frazer-Nash hydraulic, 22 kg/sq cm (300 lb/sq in)
Fire control: Palmer hydraulic
Field of fire:
Traverse: 88 degrees to each beam
Elevation: 60 degrees to each beam
Depression: 45 degrees to each beam
Weight of turret (empty): 130 kg (286 lb)
Weight of turret (full): 409 kg (950 lb)
Power source: Engine-driven pump
Armour protection: Nil
Diameter of turret ring: 87 cm (34 in)
The following aircraft types were fitted with the Nash and Thompson Type FN.4 Rear Turret.
Aircraft type: AW Whitley Mks.IV & V, Avro Manchester Mks.I & IA, Saro Lerwick, Short Stirling Mk.I, Short Sunderland Mks.II & III, and Vickers-Armstrong Wellington Mk.III (late)
Type & Mark: FN.4A: AW Whitley Mks. IV & V; Avro Manchester Mks. I & IA, Short Stirling Mks. I, Short Sunderland Mks.II & III, Vickers-Armstrong Wellington Mk.III
FN.4B: Saro Lerwick
Position: Tail
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 176 degrees
Elevation: 120 degrees
Depression: 90 degrees
Remarks:
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
British Power-Operated Gun Turrets
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company - Pt 5
The Nash and Thompson Type FN.5 Front and Tail Turrets - Pt 1
When the first Vickers Wellington Mk.Is were delivered to operational squadrons in 1938, they were armed with Vickers-built nose and tail turrets designed by Barnes Wallis. These 'gunnery windscreens' as he called them, were powered by Nash and Thompson hydraulic power systems supplied by Parnall, but the layout of the turrets left a lot to be desired. After numerous reports of malfunction and poor gunnery were investigated by experts from the A&AEE, the Air Staff decided to issue a directive to Vickers requesting the replacement of the windscreens with new front and rear defence turrets supplied by Parnall.
Frazer-Nash and Woods were summoned to the Air Ministry, where they were told of the urgent need to rearm the Wellington. They were given a development contract for a new turret which could be used in both the nose and tail positions. It was stressed that with the international situation worsening, no effort should be spared to supply the turrets as soon as possible.
The new turret, given the Type number FN.5, occupied everyone at Tolworth, and a compact turret was produced armed with twin 7.7 mm (0.303 in) Browning guns. Vickers-Armstrong's designers made the necessary alterations to the airframe to suit the new design, and a mock-up was flight-tested at Weybridge. Two prototypes were produced and fitted into a modified Wellington I at Weybridge. The rear turret functioned satisfactorily, but the nose unit was found to vibrate on take-off and landing, and when the turret was turned to the beam position in flight the trim of the aircraft was seriously affected. These faults were partially corrected but never completely cured. Following the usual teething troubles the FN.5 was accepted for use on the Wellington, changing the aircraft to Mk.IA or IC. It was also chosen as a front turret for the Short Stirling and Avro Manchester.
The two Brownings guns were fed from ammunition boxes fitted on either side of the gunner, and used as arm rests. Oxygen, intercom and electrical services were brought into the turret, together with the hydraulic feed pipes, through a rotating service joint in the top of the cupola. In common with most early Nash and Thompson turrets, the three lampholders of the Bendix signalling system were fitted to one of the structural members. The MK.IIIA reflector sight was suspended on a vee-shaped arm linked by a following-rod system to the elevation mechanism, while the sight switch, fuseboxes and floodlight were fitted above the gunner on the turret support arch.
After taking his seat the gunner closed the two access doors behind him. The catches on these doors were not very secure on the early rear defence models, and the doors would sometimes fly open without warning. If the gunner was not holding the control handles when this happened he fell backwards and could sever his oxygen pipes. Before an official modification was introduced station armourers fitted bolts on the doors. The gunner's parachute was clipped into a rack in the fuselage just outside the turret. He could abandon the aircraft by rotating the turret to
the beam stops, and after opening the doors fall backwards into space. However, before doing this he had to open the doors and retrieve his 'chute', close the doors and clip the parachute to his chest
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company - Pt 5
The Nash and Thompson Type FN.5 Front and Tail Turrets - Pt 1
When the first Vickers Wellington Mk.Is were delivered to operational squadrons in 1938, they were armed with Vickers-built nose and tail turrets designed by Barnes Wallis. These 'gunnery windscreens' as he called them, were powered by Nash and Thompson hydraulic power systems supplied by Parnall, but the layout of the turrets left a lot to be desired. After numerous reports of malfunction and poor gunnery were investigated by experts from the A&AEE, the Air Staff decided to issue a directive to Vickers requesting the replacement of the windscreens with new front and rear defence turrets supplied by Parnall.
Frazer-Nash and Woods were summoned to the Air Ministry, where they were told of the urgent need to rearm the Wellington. They were given a development contract for a new turret which could be used in both the nose and tail positions. It was stressed that with the international situation worsening, no effort should be spared to supply the turrets as soon as possible.
The new turret, given the Type number FN.5, occupied everyone at Tolworth, and a compact turret was produced armed with twin 7.7 mm (0.303 in) Browning guns. Vickers-Armstrong's designers made the necessary alterations to the airframe to suit the new design, and a mock-up was flight-tested at Weybridge. Two prototypes were produced and fitted into a modified Wellington I at Weybridge. The rear turret functioned satisfactorily, but the nose unit was found to vibrate on take-off and landing, and when the turret was turned to the beam position in flight the trim of the aircraft was seriously affected. These faults were partially corrected but never completely cured. Following the usual teething troubles the FN.5 was accepted for use on the Wellington, changing the aircraft to Mk.IA or IC. It was also chosen as a front turret for the Short Stirling and Avro Manchester.
The two Brownings guns were fed from ammunition boxes fitted on either side of the gunner, and used as arm rests. Oxygen, intercom and electrical services were brought into the turret, together with the hydraulic feed pipes, through a rotating service joint in the top of the cupola. In common with most early Nash and Thompson turrets, the three lampholders of the Bendix signalling system were fitted to one of the structural members. The MK.IIIA reflector sight was suspended on a vee-shaped arm linked by a following-rod system to the elevation mechanism, while the sight switch, fuseboxes and floodlight were fitted above the gunner on the turret support arch.
After taking his seat the gunner closed the two access doors behind him. The catches on these doors were not very secure on the early rear defence models, and the doors would sometimes fly open without warning. If the gunner was not holding the control handles when this happened he fell backwards and could sever his oxygen pipes. Before an official modification was introduced station armourers fitted bolts on the doors. The gunner's parachute was clipped into a rack in the fuselage just outside the turret. He could abandon the aircraft by rotating the turret to
the beam stops, and after opening the doors fall backwards into space. However, before doing this he had to open the doors and retrieve his 'chute', close the doors and clip the parachute to his chest
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company - Pt 6
The Nash and Thompson Type FN.5 Front and Rear Turrets - Pt 2
The turret was controlled by two separate control handles, mounted on chordal stiffeners on each side of the turret frame, either of which controlled the operating mechanism and gun firing system. The turret could be turned by hand in an emergency, by a handle to the gunner's front after the drive gear pinion had been lifted. The guns were mounted to the gunner's front in a position where the cocking studs and top covers were easily reached for charging and stoppage clearance.
The front fuselage of the Stirling was so huge that the turret was easily accommodated, with ample room for the bomb aimer's compartment below it. This was not the case in the Wellington and Manchester, where if the turret was manned, the bomb aimer was often used as a foot rest. In practice, however, the front turret was very rarely used, and was operated by the bomb aimer when it was.
The rear defence version was often in action, and was provided with 2,000 rounds per gun, compared with the front turret's 1,000 rounds per gun. The rear turret was also fitted with a drift indicator to assist the navigator. After the twin engined Manchester had proved to be unreliable in service, it was decided to replace the troublesome 24 cylinder Roll-Royce Vulture engines with four Merlins, and extend the wing centre section. The result was the famous Avro Lancaster, in which the FN.5 front and FN.20 rear turrets were retained, but the FN.7 mid-upper was dropped in favour of the roomy FN.50.
When the Lancaster began operations, complaints were made regarding the ingress of rain and draught into the front fuselage from the turret housing. Many ideas were tried to stop this, but the most effective solution proved to be tarred canvas flaps.
The Manchester and Lancaster nose installations were known as the Type FN.5A. The FN.5 series was the most widely used of all the Parnall turrets: in all, over 22,000 were produced at Yate, together with the necessary spares.
Details of the Nash and Thompson Type FN.5 Front and Rear Turret
Position: Nose: Short Stirling Mks.I, II & III, Short Sunderland Mks II, III & V, Vickers-Armstrong Wellington Mks.1A, 1C, II, III, IV & X, Vickers-Armstrong Warwick Mks. I & II, Avro Manchester Mks. I & IA, and Avro Lancaster Mks. I, II, III & VII
Tail: Vickers-Armstrong Wellington Mks.1A, 1C & III (early)
Motive power: Nash and Thompson hydraulic, WP 21 kg/sq cm (285 lb/sq in)
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition:
Nose: 1,000 rounds per gun
Tail: 2,000 rounds per gun
Fire control: Palmer hydraulic
Field of fire:
Traverse: 190 degrees
Elevation: 60 degrees
Depression: 45 degrees
Rotational speed (Maximum): 90 degrees/sec
Rotational speed (Minimum): 0.5 degrees/sec
Weight of turret:
Wellington: 115 kg (252 lb)
Stirling: 107 kg (235 lb)
Manchester/Lancaster: 108 kg (237 lb)
Diameter of ring: 88 cm (34.5 in)
Gunsight: Mk.IIIA reflector sight
The following aircraft were fitted with the Nash and Thompson FN.5 Front and Rear Turrets
Aircraft types: Vickers-Armstrong Wellington, Vickers-Armstrong Warwick, Avro Manchester, Avro Lancaster, Short Stirling and Short Sunderland
Type & Mark:
FN.5: (FN.5A: Avro Manchester & Avro Lancaster)
Position: Nose and Tail (Vickers-Armstrong Wellington Mks.1A, IC & III early)
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 190 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks:
The Nash and Thompson Engineering Company - Pt 6
The Nash and Thompson Type FN.5 Front and Rear Turrets - Pt 2
The turret was controlled by two separate control handles, mounted on chordal stiffeners on each side of the turret frame, either of which controlled the operating mechanism and gun firing system. The turret could be turned by hand in an emergency, by a handle to the gunner's front after the drive gear pinion had been lifted. The guns were mounted to the gunner's front in a position where the cocking studs and top covers were easily reached for charging and stoppage clearance.
The front fuselage of the Stirling was so huge that the turret was easily accommodated, with ample room for the bomb aimer's compartment below it. This was not the case in the Wellington and Manchester, where if the turret was manned, the bomb aimer was often used as a foot rest. In practice, however, the front turret was very rarely used, and was operated by the bomb aimer when it was.
The rear defence version was often in action, and was provided with 2,000 rounds per gun, compared with the front turret's 1,000 rounds per gun. The rear turret was also fitted with a drift indicator to assist the navigator. After the twin engined Manchester had proved to be unreliable in service, it was decided to replace the troublesome 24 cylinder Roll-Royce Vulture engines with four Merlins, and extend the wing centre section. The result was the famous Avro Lancaster, in which the FN.5 front and FN.20 rear turrets were retained, but the FN.7 mid-upper was dropped in favour of the roomy FN.50.
When the Lancaster began operations, complaints were made regarding the ingress of rain and draught into the front fuselage from the turret housing. Many ideas were tried to stop this, but the most effective solution proved to be tarred canvas flaps.
The Manchester and Lancaster nose installations were known as the Type FN.5A. The FN.5 series was the most widely used of all the Parnall turrets: in all, over 22,000 were produced at Yate, together with the necessary spares.
Details of the Nash and Thompson Type FN.5 Front and Rear Turret
Position: Nose: Short Stirling Mks.I, II & III, Short Sunderland Mks II, III & V, Vickers-Armstrong Wellington Mks.1A, 1C, II, III, IV & X, Vickers-Armstrong Warwick Mks. I & II, Avro Manchester Mks. I & IA, and Avro Lancaster Mks. I, II, III & VII
Tail: Vickers-Armstrong Wellington Mks.1A, 1C & III (early)
Motive power: Nash and Thompson hydraulic, WP 21 kg/sq cm (285 lb/sq in)
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition:
Nose: 1,000 rounds per gun
Tail: 2,000 rounds per gun
Fire control: Palmer hydraulic
Field of fire:
Traverse: 190 degrees
Elevation: 60 degrees
Depression: 45 degrees
Rotational speed (Maximum): 90 degrees/sec
Rotational speed (Minimum): 0.5 degrees/sec
Weight of turret:
Wellington: 115 kg (252 lb)
Stirling: 107 kg (235 lb)
Manchester/Lancaster: 108 kg (237 lb)
Diameter of ring: 88 cm (34.5 in)
Gunsight: Mk.IIIA reflector sight
The following aircraft were fitted with the Nash and Thompson FN.5 Front and Rear Turrets
Aircraft types: Vickers-Armstrong Wellington, Vickers-Armstrong Warwick, Avro Manchester, Avro Lancaster, Short Stirling and Short Sunderland
Type & Mark:
FN.5: (FN.5A: Avro Manchester & Avro Lancaster)
Position: Nose and Tail (Vickers-Armstrong Wellington Mks.1A, IC & III early)
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 190 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks:
You do not have the required permissions to view the files attached to this post.
Last edited by Robert Hurst on 15 May 2003 11:05, edited 3 times in total.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company - Pt 7
The Nash and Thompson Type FN.6 Nose Turret
The only information on this turret is as follows:
Aircraft type: Unknown
Type & Mark: FN.6
Position: Nose
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Remarks: Design only
The Nash and Thompson Type FN.7 Mid-upper Turret
The FN.7 was designed for the Blackburn Botha which was not a success and was relegated to training duties after performance proved to be well below requirements. In its original form, the FN.7 was larger than the final production model; it was found that the high egg-shaped cupola had a marked effect on the aircraft's handling and stability, and so it was cut down in size. The modified turret had a lower profile, but this made the gunner's position very cramped and access into and out of the seat was difficult.
At the back of the turret were two escape doors which on the original design provided the gunner with a reasonable means of abandoning the aircraft. These doors were retained on the production version, but now proved almost impossible for a gunner in bulky flying clothing to use. Following reports that gunners who had used the doors to escape from Stirling aircraft had hit the tailplane and been killed, the doors were sealed and gunners were instructed to use the fuselage hatches.
The twin Browning guns were mounted on a very compact gun cradle directly in front of the gunner, and closer together than usual on Nash and Thompson designs. This arrangement gave a good field of view to the gunner's front, but the doors and framing cut off any vision on a 180 degrees arc to his rear. Another drawback was that the asymmetrical shape of the cupola put a heavy strain on the hydraulical-rotation motor, which caused uneven speed of rotation and made it difficult to follow a target accurately. Ammuniiton was stored in two 500-round boxes, one either side of the gunner. The belts were drawn through 90 degrees and into the gun feed units through slots in the cradle housing.
A Mk.IIIA reflector sight was mounted on a vee-shaped arm. As can be seen, the gunner's head was close to the main support tube. The oval pad is a 'cheek or ear pad' used to steady the gunner's head when aiming. This was found to be unnecessary, and was not fitted after 1940. The sight switch and fuses were mounted on a small panel on the gunner's right, and the three Bendix signalling lamps and controls fixed to a side support member on the right. A floodlight was fixed to a movable arm clipped on the right of the turret support tube.
The FN.7 was not popular with gunners, the cramped conditions and difficult escape route doing nothing for its image. The turret was installed in 209 Avro Manchester Mks.I & IA's, 712 Short Stirling Mk.I's, 580 Blackburn Bothas, 649 Short Sunderlands. Five Blackburn Rocs were fitted with FN.7s at Squires Gate gunnery training school: these were used for air firing practice over the Irish Sea.
Details of the Nash and Thompson Type FN.7 Mid-upper Turret
Position in aircraft: Mid-upper
Motive power: FN hydraulic from electrically driven duplex pump
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammuntion: 500-rounds per gun from boxes in turret
Gunsight: Mk.IIIA free gun reflector sight
Fire control: Palmer hydraulic system
Field of fire:
Traverse: 360 degrees
Elevation: 75 degrees
Depression: 38 degrees
Weight of turret (empty): 148 kg (325 lb)
Weight of turret with guns and ammunition: 207 kg (455 lb)
The following aircraft types were fitted with the Nash and Thompson Type FN.7 Mid-upper Turret
Aircraft type: Avro Manchester Mks. I & IA, Blackburn Botha, Short Stirling Mk.I & Short Sunderland Mks. II, III & V
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 75 degrees
Depression: 398 degrees
Remarks
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company - Pt 7
The Nash and Thompson Type FN.6 Nose Turret
The only information on this turret is as follows:
Aircraft type: Unknown
Type & Mark: FN.6
Position: Nose
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Remarks: Design only
The Nash and Thompson Type FN.7 Mid-upper Turret
The FN.7 was designed for the Blackburn Botha which was not a success and was relegated to training duties after performance proved to be well below requirements. In its original form, the FN.7 was larger than the final production model; it was found that the high egg-shaped cupola had a marked effect on the aircraft's handling and stability, and so it was cut down in size. The modified turret had a lower profile, but this made the gunner's position very cramped and access into and out of the seat was difficult.
At the back of the turret were two escape doors which on the original design provided the gunner with a reasonable means of abandoning the aircraft. These doors were retained on the production version, but now proved almost impossible for a gunner in bulky flying clothing to use. Following reports that gunners who had used the doors to escape from Stirling aircraft had hit the tailplane and been killed, the doors were sealed and gunners were instructed to use the fuselage hatches.
The twin Browning guns were mounted on a very compact gun cradle directly in front of the gunner, and closer together than usual on Nash and Thompson designs. This arrangement gave a good field of view to the gunner's front, but the doors and framing cut off any vision on a 180 degrees arc to his rear. Another drawback was that the asymmetrical shape of the cupola put a heavy strain on the hydraulical-rotation motor, which caused uneven speed of rotation and made it difficult to follow a target accurately. Ammuniiton was stored in two 500-round boxes, one either side of the gunner. The belts were drawn through 90 degrees and into the gun feed units through slots in the cradle housing.
A Mk.IIIA reflector sight was mounted on a vee-shaped arm. As can be seen, the gunner's head was close to the main support tube. The oval pad is a 'cheek or ear pad' used to steady the gunner's head when aiming. This was found to be unnecessary, and was not fitted after 1940. The sight switch and fuses were mounted on a small panel on the gunner's right, and the three Bendix signalling lamps and controls fixed to a side support member on the right. A floodlight was fixed to a movable arm clipped on the right of the turret support tube.
The FN.7 was not popular with gunners, the cramped conditions and difficult escape route doing nothing for its image. The turret was installed in 209 Avro Manchester Mks.I & IA's, 712 Short Stirling Mk.I's, 580 Blackburn Bothas, 649 Short Sunderlands. Five Blackburn Rocs were fitted with FN.7s at Squires Gate gunnery training school: these were used for air firing practice over the Irish Sea.
Details of the Nash and Thompson Type FN.7 Mid-upper Turret
Position in aircraft: Mid-upper
Motive power: FN hydraulic from electrically driven duplex pump
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammuntion: 500-rounds per gun from boxes in turret
Gunsight: Mk.IIIA free gun reflector sight
Fire control: Palmer hydraulic system
Field of fire:
Traverse: 360 degrees
Elevation: 75 degrees
Depression: 38 degrees
Weight of turret (empty): 148 kg (325 lb)
Weight of turret with guns and ammunition: 207 kg (455 lb)
The following aircraft types were fitted with the Nash and Thompson Type FN.7 Mid-upper Turret
Aircraft type: Avro Manchester Mks. I & IA, Blackburn Botha, Short Stirling Mk.I & Short Sunderland Mks. II, III & V
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 75 degrees
Depression: 398 degrees
Remarks
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
Last edited by Robert Hurst on 16 May 2003 13:51, edited 1 time in total.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.8 Mid-upper Turret
This was a modification of the FN.7 turret for use with the Saro Lerwick flying-boat.
The following aircraft was fitted with the Nash and Thompson Type FN.8 Mid-upper Turret.
Aircraft type: Saro Lerwick
Type & Mark: FN.8
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II; 1,000 rounds of ammunition
Traverse:
Elevation:
Depression:
Remarks: Modified FN.7
The Nash and Thompson Type FN.9 Mid-under Turret.
Aircraft type: Unknown
Type & Mark: FN.9
Position: Mid-under
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II; 1,000 rounds of ammunition
Traverse:
Elevation:
Depression:
Remarks: Prototype only.
The Nash and Thompson Type FN.10 Tail Turret.
Aircraft type:
Type & Mark: FN.10
Position: Tail
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II; 1,000 rounds of ammunition
Traverse:
Elevation:
Depression:
Remarks: Experimental mock-up
The above text was taken from "British Aircraft Armament Vol.1: RAF Guns and Turrets", by R Wallace Clarke. The top photo was taken from "RAF Coastal Command 1936-1969", by Chris Ashworth. The bottom photo was taken from "Armament of British Aircraft 1909-1939", by H F King.
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.8 Mid-upper Turret
This was a modification of the FN.7 turret for use with the Saro Lerwick flying-boat.
The following aircraft was fitted with the Nash and Thompson Type FN.8 Mid-upper Turret.
Aircraft type: Saro Lerwick
Type & Mark: FN.8
Position: Mid-upper
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II; 1,000 rounds of ammunition
Traverse:
Elevation:
Depression:
Remarks: Modified FN.7
The Nash and Thompson Type FN.9 Mid-under Turret.
Aircraft type: Unknown
Type & Mark: FN.9
Position: Mid-under
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II; 1,000 rounds of ammunition
Traverse:
Elevation:
Depression:
Remarks: Prototype only.
The Nash and Thompson Type FN.10 Tail Turret.
Aircraft type:
Type & Mark: FN.10
Position: Tail
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II; 1,000 rounds of ammunition
Traverse:
Elevation:
Depression:
Remarks: Experimental mock-up
The above text was taken from "British Aircraft Armament Vol.1: RAF Guns and Turrets", by R Wallace Clarke. The top photo was taken from "RAF Coastal Command 1936-1969", by Chris Ashworth. The bottom photo was taken from "Armament of British Aircraft 1909-1939", by H F King.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
Last edited by Robert Hurst on 17 May 2003 10:27, edited 1 time in total.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.11 Nose Turret
The Nash and Thompson FN.11 was designed for the bow (nose) of the Sunderland flying-boat. It was mounted on rails to enable it to be moved back into the nose section when mooring the aircraft. The ammunition for the single Vickers K gun was contained inside the turret, four spare drums being stowed on pegs within reach of the gunner. The hydraulic, electrical and oxygen services were brought in on flexible pipelines for retraction purposes.
The FN.11 was the first of the new generation of Nash and Thompson turrets. The gun was offset to starboard, enabling the gunner's seat to be central. He had a perfect view ahead, ideal for searching the sea. The Tolworth designers managed to keep the weight down to 59 kg (130 lb) empty, which for a fully powered turret was quite an achievement. A twin handle control was mounted directly on the valve box in front of the gunner, triggers operating Palmer hydraulic gun-firing units via Bowden cables. As the gun used 50-round (rarely, 100) ammunition drums there was no need for elaborate belt ducting and boxes.
Details of the Nash and Thompson Type FN.11 Nose Turret
Position in aircraft: Nose
Power system: Nash and Thompson hdraulic system
Working pressure: 22 kg/sq cm (300 lb/sq in)
Armament: One 7.7 mm (0.303 in) Vickers K gun
Ammunition: Five 50-round drums
Sights (early): Norman Vane; later Mk.IIIA reflector sight
Fire control: Palmer hydraulic
Field of fire:
Traverse: 60 degrees to each beam
Elevation: 60 degrees
Depression: 45 degrees
Diameter of turret ring: (45 in)
Weight of turret (empty): 59 kg (130 lb)
Weight of turret (armed): 91 kg (200 lb)
Armour protection: None
The following aircraft was fitted with the Nash and Thompson Type FN.11 Nose Turret.
Aircraft type: Short Sunderland Mk.I
Type & Mark: FN.11
Position: Nose
Guns: 1 x 7.7 mm (0.303 in) Vickers K
Traverse: 120 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks: Later replaced with the FN.5 turret
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.11 Nose Turret
The Nash and Thompson FN.11 was designed for the bow (nose) of the Sunderland flying-boat. It was mounted on rails to enable it to be moved back into the nose section when mooring the aircraft. The ammunition for the single Vickers K gun was contained inside the turret, four spare drums being stowed on pegs within reach of the gunner. The hydraulic, electrical and oxygen services were brought in on flexible pipelines for retraction purposes.
The FN.11 was the first of the new generation of Nash and Thompson turrets. The gun was offset to starboard, enabling the gunner's seat to be central. He had a perfect view ahead, ideal for searching the sea. The Tolworth designers managed to keep the weight down to 59 kg (130 lb) empty, which for a fully powered turret was quite an achievement. A twin handle control was mounted directly on the valve box in front of the gunner, triggers operating Palmer hydraulic gun-firing units via Bowden cables. As the gun used 50-round (rarely, 100) ammunition drums there was no need for elaborate belt ducting and boxes.
Details of the Nash and Thompson Type FN.11 Nose Turret
Position in aircraft: Nose
Power system: Nash and Thompson hdraulic system
Working pressure: 22 kg/sq cm (300 lb/sq in)
Armament: One 7.7 mm (0.303 in) Vickers K gun
Ammunition: Five 50-round drums
Sights (early): Norman Vane; later Mk.IIIA reflector sight
Fire control: Palmer hydraulic
Field of fire:
Traverse: 60 degrees to each beam
Elevation: 60 degrees
Depression: 45 degrees
Diameter of turret ring: (45 in)
Weight of turret (empty): 59 kg (130 lb)
Weight of turret (armed): 91 kg (200 lb)
Armour protection: None
The following aircraft was fitted with the Nash and Thompson Type FN.11 Nose Turret.
Aircraft type: Short Sunderland Mk.I
Type & Mark: FN.11
Position: Nose
Guns: 1 x 7.7 mm (0.303 in) Vickers K
Traverse: 120 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks: Later replaced with the FN.5 turret
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.12 Nose Turret
This nose turret was designed for the Lerwick flying-boat of Coastal Command, which was very unsuccessful and served a single squadron for one year. When the specification was issued Parnall Aircraft submitted their Type 11 (Sunderland) turret, but the Sauders-Roe designers requested an improved field of vision and twin Vickers K guns. A completely new design was produced, in which the gun cradle was mounted lower and in a central position: this, the second front turret to emanate from the Tolworth design office was the Type FN.12.
When it was air tested it was found that the guns and their drum magazines restricted the gunner's movements. After the first three turrets had been manufactured it was decided to revert to the single gun of the FN.11. For some reason the turret was then reclassified as the Type FN.26. Full detailed description of this turret will be given later under FN.26.
Details of the Nash and Thompson Type FN.12 Nose Turret
Position in aircraft: Nose
Motive force: Nash and Thompson hydraulic system from engine-driven
Beacham-type pump
Armament: Two 7.7 mm (0.303 in) Vickers K guns
Fire control: Palmer hydraulic
Field of fire:
Traverse: 90 degrees either side of centre
Elevation: 65 degrees
Depression: 45 degrees
Gunsight: Mk.IIIA reflector sight
Ammunition: Six 50-round drums
Weight (empty): 64 kg (140 lb)
Weight with guns and ammunition: 109 kg (240 lb)
The following aircraft was fitted with the Nash and Thompson Type FN.12 Nose Turret
Aircraft type: Saro Lerwick
Type & Mark: FN.12
Position: Nose
Guns: 2 x 7.7 mm (0.303 in) Vickers K
Traverse: 180 degrees
Elevation: 65 degrees
Depression: 45 degrees
Remarks: Only three turrets built. Replaced by FN.26 turret.
The above text was taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.12 Nose Turret
This nose turret was designed for the Lerwick flying-boat of Coastal Command, which was very unsuccessful and served a single squadron for one year. When the specification was issued Parnall Aircraft submitted their Type 11 (Sunderland) turret, but the Sauders-Roe designers requested an improved field of vision and twin Vickers K guns. A completely new design was produced, in which the gun cradle was mounted lower and in a central position: this, the second front turret to emanate from the Tolworth design office was the Type FN.12.
When it was air tested it was found that the guns and their drum magazines restricted the gunner's movements. After the first three turrets had been manufactured it was decided to revert to the single gun of the FN.11. For some reason the turret was then reclassified as the Type FN.26. Full detailed description of this turret will be given later under FN.26.
Details of the Nash and Thompson Type FN.12 Nose Turret
Position in aircraft: Nose
Motive force: Nash and Thompson hydraulic system from engine-driven
Beacham-type pump
Armament: Two 7.7 mm (0.303 in) Vickers K guns
Fire control: Palmer hydraulic
Field of fire:
Traverse: 90 degrees either side of centre
Elevation: 65 degrees
Depression: 45 degrees
Gunsight: Mk.IIIA reflector sight
Ammunition: Six 50-round drums
Weight (empty): 64 kg (140 lb)
Weight with guns and ammunition: 109 kg (240 lb)
The following aircraft was fitted with the Nash and Thompson Type FN.12 Nose Turret
Aircraft type: Saro Lerwick
Type & Mark: FN.12
Position: Nose
Guns: 2 x 7.7 mm (0.303 in) Vickers K
Traverse: 180 degrees
Elevation: 65 degrees
Depression: 45 degrees
Remarks: Only three turrets built. Replaced by FN.26 turret.
The above text was taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
Last edited by Robert Hurst on 19 May 2003 14:55, edited 2 times in total.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.13 Tail Turret
The FN.13 tail turret was designed especially for the Sunderland and, from the outset, a major consideration was maximum field of view. As can be seen from the illustration, the cupola was more elongated than usual, and the gun cradles were lower, giving the gunner an excellent view when searching the sea during long ocean patrols. The four 7.7 mm (0.303 in) Browning guns were mounted on a common bridge, which pivoted on two large-diameter bearings in brackets fixed to the inner, rotating turret ring. The gun bridge was actuated by two double-acting hydraulic rams connected to the gun bridge drop arms, the lower ends of the rams being anchored to the turret floor by hinged connections.
The turret was rotated by a hydraulic motor attached to the inner ring, geared directly to a circular track secured to the outer fixed ring.
The seat was adjusted by withdrawing a spring-loaded plunger, giving two positions of height. The control handles were similar to those of the FN.7 turret, being mounted on two columns which extended in a vee shape from the valve box - one on the left, and the other on the right of the guns - at a convenient height for the gunner. Either handle gave complete control of turret rotation, gun elevation, gun firing and master valve operation.
The Palmer hydraulic gun-firing control was operated by Bowden cables actuated by finger triggers on the control handles. Empty cases and links were discharged through chutes into a container under the turret bridge which could be emptied by elevating the guns to maximum. This automatically opened a section of the container, and the contents fell into the slipstream.
Luftwaffe pilots were warned never to attack Sunderlands from the rear as the tail turret was particularly effective, an instruction which confirmed the efficiency of this design. Early in the Second World War a single Sunderland fought off an hour-long attack by three Junkers Ju.88 aircraft, shooting down one and damaging another.
Details of the Nash and Thompson Type FN.13 Rear Turret
Position in aircraft: Tail
Motive power: Hydraulic from engine-driven pump
Armament: Four 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 500 round per gun
Fire control: Palmer hydraulic
Field of fire:
Traverse: 180 degrees
Elevation: 60 degrees
Depression: 45 degrees
Gunsight: Mk.IIIA free mounted reflector sight
Weight of turret (empty): 91 kg (200 lb)
Source of power: Engine-driven pump
Diameter of ring: 87 cm (34 in)
Armour protection: None
Hydraulic working pressure: 22 kg/sq cm (200 lb/sq in)
The following aircraft was fitted with the Nash and Thompson Type FN.13 Tail Turret:
Aircraft type: Short Sunderland Mk.I
Type & Mark: FN.13
Position: Tail
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 180 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks: Later replaced by FN.4, FN.20
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.13 Tail Turret
The FN.13 tail turret was designed especially for the Sunderland and, from the outset, a major consideration was maximum field of view. As can be seen from the illustration, the cupola was more elongated than usual, and the gun cradles were lower, giving the gunner an excellent view when searching the sea during long ocean patrols. The four 7.7 mm (0.303 in) Browning guns were mounted on a common bridge, which pivoted on two large-diameter bearings in brackets fixed to the inner, rotating turret ring. The gun bridge was actuated by two double-acting hydraulic rams connected to the gun bridge drop arms, the lower ends of the rams being anchored to the turret floor by hinged connections.
The turret was rotated by a hydraulic motor attached to the inner ring, geared directly to a circular track secured to the outer fixed ring.
The seat was adjusted by withdrawing a spring-loaded plunger, giving two positions of height. The control handles were similar to those of the FN.7 turret, being mounted on two columns which extended in a vee shape from the valve box - one on the left, and the other on the right of the guns - at a convenient height for the gunner. Either handle gave complete control of turret rotation, gun elevation, gun firing and master valve operation.
The Palmer hydraulic gun-firing control was operated by Bowden cables actuated by finger triggers on the control handles. Empty cases and links were discharged through chutes into a container under the turret bridge which could be emptied by elevating the guns to maximum. This automatically opened a section of the container, and the contents fell into the slipstream.
Luftwaffe pilots were warned never to attack Sunderlands from the rear as the tail turret was particularly effective, an instruction which confirmed the efficiency of this design. Early in the Second World War a single Sunderland fought off an hour-long attack by three Junkers Ju.88 aircraft, shooting down one and damaging another.
Details of the Nash and Thompson Type FN.13 Rear Turret
Position in aircraft: Tail
Motive power: Hydraulic from engine-driven pump
Armament: Four 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 500 round per gun
Fire control: Palmer hydraulic
Field of fire:
Traverse: 180 degrees
Elevation: 60 degrees
Depression: 45 degrees
Gunsight: Mk.IIIA free mounted reflector sight
Weight of turret (empty): 91 kg (200 lb)
Source of power: Engine-driven pump
Diameter of ring: 87 cm (34 in)
Armour protection: None
Hydraulic working pressure: 22 kg/sq cm (200 lb/sq in)
The following aircraft was fitted with the Nash and Thompson Type FN.13 Tail Turret:
Aircraft type: Short Sunderland Mk.I
Type & Mark: FN.13
Position: Tail
Guns: 4 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 180 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks: Later replaced by FN.4, FN.20
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Handley Page Harrow Turrets: Nash and Thompson Types FN.14 (Nose) and FN.15 (Tail).
Following the success of the Nash and Thompson hydraulic control in the Hawker Demon, several aircraft companies used these controls to power turrets of their own design. One of these was Handley Page. When the RAF expansion scheme was launched, this company decided to update the HP.51 bomber-transport prototype into the HP.54 heavy bomber, to be known as the Harrow. It was to be equipped with three defensive gun positions: nose and tail enclosed power turrets, and a hand-held mid-upper cupola.
The mid-upper turret was soon abandoned and the first few production aircraft, the Mk.Is, were in fact flown without the new turrets. When they were installed, the Harrow became the first heavy bomber in service to
be armed with power turrets and were known as the Harrow Mk.II.
The nose turret, the Type FN.14, was armed with a single Lewis gun, and the Type FN.15 tail turret being fitted with two Lewis guns and, apart from the driving mechanism, the turrets were designed by Handley Page. In both, the main transparent upper part of the cupola was fixed. In the absence of moving parts this gave an excellent field of view as well as an aerodynamically clean shape, in the FN.13 provision was made for bomb sighting through a flat glazed panel. The rotatable Nash and Thompson part of the turret consisted of the gunner's seat, the guns and their mountings, and the reflector sight. The gun barrels protruded through slots in a semi-circular windshield belt which traversed round the lower part of the turret. These rotating parts were attached to a circular bowl suspended on roller bearings fixed in an outer ring bolted to the airframe. The guns were mounted on support arms coupled at the forward end by a torque tube and pivoted on bearings. The piston rod ends of the elevation rams were connected to the gun arms, the lower ends being hinged to the turret roof. The right-hand gun in the rear turret was fitted with a cartridge case deflector to protect the gunner's legs from ejected empties. Spare ammunition drums for the Lewis guns were mounted on the fuselage structure conveniently near the gunner. As the guns were mounted in a low position, access for drum changing and stoppage clearance was not ideal. Four seat heights could be selected by a lever beneath the seat, plus an upper position for observation.
As usual the control handles were mounted on the hydraulic valve box which was fixed to the floor. The column could be adjusted for reach. The reflector sight, with cheek pad, was mounted at eye level, coupled by parallel linkage to the gun arm.
In service the Harrow turrets proved quite efficient but cramped. The Lewis guns were prone to stoppages, and were replaced by the Vickers K. However, fumes were troublesome after prolonged firing, so ventilators were installed. The Handley Page designers had provided the last word in defensive armament, and if hostilities had occurred at this time, the Harrow would have been no pushover for the fighters of the period.
Parnall alloted type numbers to the turrets for the purpose of spares, the various Nash and Thompson parts being supplied to Handley Page in the form of complete made-up units, including engine-mounted pumps and recuperators.
Details of the Nash and Thompson FN.14 and FN.15 Turrets
Position in aircraft:
Nose: FN.14
Tail: FN.15
Motive power: Frazer-Nash hydraulic system
Armament:
Nose: One 7.7 mm (0.303 in) Lewis Mk.III Gun
Tail: Two 7.7 mm (0.303 in) Lewis Mk.III Guns; Later replaced by 7.7 mm (0.303 in) Vickers K Guns in both turrets.
Ammunition: Eight 97-round drums
Fire control: Bowden cable activating hydraulic sear releases
Field of fire:
Traverse: 60 degrees to either beam
Elevation: 60 degrees
Depression: 45 degrees
Gunsight: Mk.IIIA free gun reflector sight
The following aircraft was fitted with the Nash and Thompson FN.14 and FN.15 Turrets.
Aircraft type: Handley Page Harrow
Type and Mark: FN.14 and FN.15
Position: FN.14 Nose; FN.15 Tail
Guns:
FN.14 1 x 7.7 mm (0.303 in) Lewis Mk.III
FN.15 2 x 7.7 mm (0.303 in) Lewis Mk.III
Traverse: 120 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks:
The above text and photo were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company
The Handley Page Harrow Turrets: Nash and Thompson Types FN.14 (Nose) and FN.15 (Tail).
Following the success of the Nash and Thompson hydraulic control in the Hawker Demon, several aircraft companies used these controls to power turrets of their own design. One of these was Handley Page. When the RAF expansion scheme was launched, this company decided to update the HP.51 bomber-transport prototype into the HP.54 heavy bomber, to be known as the Harrow. It was to be equipped with three defensive gun positions: nose and tail enclosed power turrets, and a hand-held mid-upper cupola.
The mid-upper turret was soon abandoned and the first few production aircraft, the Mk.Is, were in fact flown without the new turrets. When they were installed, the Harrow became the first heavy bomber in service to
be armed with power turrets and were known as the Harrow Mk.II.
The nose turret, the Type FN.14, was armed with a single Lewis gun, and the Type FN.15 tail turret being fitted with two Lewis guns and, apart from the driving mechanism, the turrets were designed by Handley Page. In both, the main transparent upper part of the cupola was fixed. In the absence of moving parts this gave an excellent field of view as well as an aerodynamically clean shape, in the FN.13 provision was made for bomb sighting through a flat glazed panel. The rotatable Nash and Thompson part of the turret consisted of the gunner's seat, the guns and their mountings, and the reflector sight. The gun barrels protruded through slots in a semi-circular windshield belt which traversed round the lower part of the turret. These rotating parts were attached to a circular bowl suspended on roller bearings fixed in an outer ring bolted to the airframe. The guns were mounted on support arms coupled at the forward end by a torque tube and pivoted on bearings. The piston rod ends of the elevation rams were connected to the gun arms, the lower ends being hinged to the turret roof. The right-hand gun in the rear turret was fitted with a cartridge case deflector to protect the gunner's legs from ejected empties. Spare ammunition drums for the Lewis guns were mounted on the fuselage structure conveniently near the gunner. As the guns were mounted in a low position, access for drum changing and stoppage clearance was not ideal. Four seat heights could be selected by a lever beneath the seat, plus an upper position for observation.
As usual the control handles were mounted on the hydraulic valve box which was fixed to the floor. The column could be adjusted for reach. The reflector sight, with cheek pad, was mounted at eye level, coupled by parallel linkage to the gun arm.
In service the Harrow turrets proved quite efficient but cramped. The Lewis guns were prone to stoppages, and were replaced by the Vickers K. However, fumes were troublesome after prolonged firing, so ventilators were installed. The Handley Page designers had provided the last word in defensive armament, and if hostilities had occurred at this time, the Harrow would have been no pushover for the fighters of the period.
Parnall alloted type numbers to the turrets for the purpose of spares, the various Nash and Thompson parts being supplied to Handley Page in the form of complete made-up units, including engine-mounted pumps and recuperators.
Details of the Nash and Thompson FN.14 and FN.15 Turrets
Position in aircraft:
Nose: FN.14
Tail: FN.15
Motive power: Frazer-Nash hydraulic system
Armament:
Nose: One 7.7 mm (0.303 in) Lewis Mk.III Gun
Tail: Two 7.7 mm (0.303 in) Lewis Mk.III Guns; Later replaced by 7.7 mm (0.303 in) Vickers K Guns in both turrets.
Ammunition: Eight 97-round drums
Fire control: Bowden cable activating hydraulic sear releases
Field of fire:
Traverse: 60 degrees to either beam
Elevation: 60 degrees
Depression: 45 degrees
Gunsight: Mk.IIIA free gun reflector sight
The following aircraft was fitted with the Nash and Thompson FN.14 and FN.15 Turrets.
Aircraft type: Handley Page Harrow
Type and Mark: FN.14 and FN.15
Position: FN.14 Nose; FN.15 Tail
Guns:
FN.14 1 x 7.7 mm (0.303 in) Lewis Mk.III
FN.15 2 x 7.7 mm (0.303 in) Lewis Mk.III
Traverse: 120 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks:
The above text and photo were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson FN.16 Nose Turret
When the company was asked to submit a nose turret for the new Armstrong Whitworth Whitley, it was suggested that the FN.11 could be easily adapted. It was agreed that this would save unnecessary duplication, and the turret was adapted for use in place of the manually operated Armstrong Whitworth turret. The Whitley conversion needed several structural modifications, and was given a new Type number - FN.16. The gunner pulled himself up from the bomb aimer's compartment in the nose, and clipped a sling-type seat under him. He had an excellent view ahead. The first FN.11 and 16 turrets had Norman Vane sights, but these were soon replaced with the first production Mk.III reflector sights. The FN.16 services were brought into the turret through a rotating service joint in the roof of the cupola, and taken to the various outlets from flexible connections.
When Whitley squadrons commenced operations it was found that the turret was used almost wholly for dousing searchlights. It was also found that a vertical black line painted down the front of the Perspex enabled the gunner to assist in measuring drift. The gun protruded through a slot which was made almost draught- and waterproof by a system of sheaved overlapping plates moving with the elevation of the gun.
From hindsight, if there was one gun position in which a heavy-calibre gun would have been invaluable, it was in the front turret of Coastal Command aircraft. the relatively short-range and hitting power of the rifle-calibre guns made it possible for Whitleys and Sunderlands to be shot down by U-boats long before the latter came into range.
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
The details of the Nash and Thompson FN.16 Nose Turret
These can be found under the FN.11
The following aircraft was fitted with the Nash and Thompson FN.16 Nose Turret
Aircraft type: Armstrong Whitworth Whitley
Type & Mark: FN.16
Position: Nose:
Guns: 1 x 7.7 mm (0.303 in) Vickers K
Traverse: 120 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks: Same as FN.11 (but non-retractable)
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson FN.16 Nose Turret
When the company was asked to submit a nose turret for the new Armstrong Whitworth Whitley, it was suggested that the FN.11 could be easily adapted. It was agreed that this would save unnecessary duplication, and the turret was adapted for use in place of the manually operated Armstrong Whitworth turret. The Whitley conversion needed several structural modifications, and was given a new Type number - FN.16. The gunner pulled himself up from the bomb aimer's compartment in the nose, and clipped a sling-type seat under him. He had an excellent view ahead. The first FN.11 and 16 turrets had Norman Vane sights, but these were soon replaced with the first production Mk.III reflector sights. The FN.16 services were brought into the turret through a rotating service joint in the roof of the cupola, and taken to the various outlets from flexible connections.
When Whitley squadrons commenced operations it was found that the turret was used almost wholly for dousing searchlights. It was also found that a vertical black line painted down the front of the Perspex enabled the gunner to assist in measuring drift. The gun protruded through a slot which was made almost draught- and waterproof by a system of sheaved overlapping plates moving with the elevation of the gun.
From hindsight, if there was one gun position in which a heavy-calibre gun would have been invaluable, it was in the front turret of Coastal Command aircraft. the relatively short-range and hitting power of the rifle-calibre guns made it possible for Whitleys and Sunderlands to be shot down by U-boats long before the latter came into range.
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
The details of the Nash and Thompson FN.16 Nose Turret
These can be found under the FN.11
The following aircraft was fitted with the Nash and Thompson FN.16 Nose Turret
Aircraft type: Armstrong Whitworth Whitley
Type & Mark: FN.16
Position: Nose:
Guns: 1 x 7.7 mm (0.303 in) Vickers K
Traverse: 120 degrees
Elevation: 60 degrees
Depression: 45 degrees
Remarks: Same as FN.11 (but non-retractable)
Regards
Bob
You do not have the required permissions to view the files attached to this post.
Last edited by Robert Hurst on 20 May 2003 14:54, edited 2 times in total.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.17 Mid-under Turret
During the design of the Armstrong Whitworth Whitley, it was realised that an under defence gun position would have to be provided. In the late mid-1930s the usual solution was a manually retractable 'dust-bin'-type turret equipped with one or two hand-operated machine-guns. The Junkers Ju 86 and Handley Page Heyford under turrets were examples of the current design thinking at this time, providing defence from fighter attack from below. A development contract was awarded to Parnall for a suitable design incorporating the Frazer-Nash hydraulic system.
The Parnall designers found that the main problem was excess weight: hydraulic rams and valve boxes had to be provided for both turret operation and retraction, and the main frame had to be sufficiently strong to withstand the pressure of the slipstream and the considerable weight of controls, guns and ammunition and, of course the gunner.
The resulting design consisted of a circular drum attached to an inner turret ring which revolved on roller bearings running in a fixed outer ring, rotated by a hydraulic motor mounted on the inner ring. The outer ring was attached to a cylindrical superstructure which was raised or lowered between guide bars in the fuselage.The turret was raised and lowered by hydraulic rams connected at their lower ends to the guide bars and at their upper ends to the superstructure.
The operating sequence was as follows: the gunner in the fuselage extended the turret by moving a lever which actuated the retraction rams. When it was fully extended he crouched between the two steadying beams and, using the tread plates provided carefully stepped down into his small seat. As the seat was fixed to the base of the turret, he then extended the footwell by winding a small handle fixed in the centre of an instrument panel to his front. He then lowered his legs into it. The reflector sight was then switched on, being fixed on a gimbal ring, attached to a radius arm which moved in harmony with the guns. The two 7.7 mm (0.303 in) Browning guns were mounted in cradles, one on each side of the turret, and pivoted on bearings fitted on stiff brackets secured to the inner turret ring and actuated by rams. Ammunition was carried in two 500 round boxes in the top of the turret, fed into the breeches by chutes. Having connected his oxygen supply he cocked the guns and was ready for action. To his front was a narrow Perspex window running from top to bottom, but it was only 152 mm (6 in) wide. There were also side windows, but as these were cut into the frame only where there was no interference from equipment, the gunner's vision was far from ideal.
In theory the aircraft was now provided with a power-operated under turret, with complete 360 degrees traverse, ready to deal with attack from below. In practice, however, the turret was seldom used. The basic flaw in the whole design concept was that when a bomber was under attack, the extended turret slowed the aircraft's speed by 17-33 kph (10-20 mph), and this, coupled with the questionable visibility of the gunner, led the crews to decide that the turret was more of a liability than an asset.
Another rather serious fault with the FN.17 was the tendency of the turret to extend unintentionally during flight. This was caused by hydraulic valve 'creep' and several serious landing accidents were caused by this fault.
The FN.17 was installed in the early production Whitley Mks. I, II, III & IV, but due to the reasons stated, was soon taken out by operational squadrons. The turrets were not installed in any Whitleys after the Mk.IV. When the Whitley became obsolescent as a bomber it was used extensively for paratroop and supply dropping, and the circular hole previously used by the turret proved an ideal exit for this purpose. For this reason all production Whitleys retained the turret hole in the fuselage floor.
Details of the Nash and Thompson FN.17 Mid-under Turret.
Position in aircraft: Mid-under
Motive power: Hydraulic from engine-driven pump
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 500 rounds per gun
Gunsight: Mk.IIIA free mounted gun sight
Fire control: Palmer hydraulic
Field of fire:
Traverse: 360 degrees
Elevation (max): 6 degrees
Depression: 50 degrees
Weight of turret (empty): 168 kg (370 lb)
Weight of turret with guns and ammunition: 325 kg (715 lb)
Diameter of ring: 87 cm (34 in)
Hydraulic working pressure: 22 kg/sq cm (300 lb/sq in)
Armour: None
The following aircraft were fitted with the Nash and Thompson FN.17 Mid-under Turret.
Aircraft type: Armstrong Whitworth Whitley Mks. I , II, II and IV
Type & Mark: FN.17
Position: Mid-under
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 6 degrees
Depression: 50 degrees
Remarks:
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.17 Mid-under Turret
During the design of the Armstrong Whitworth Whitley, it was realised that an under defence gun position would have to be provided. In the late mid-1930s the usual solution was a manually retractable 'dust-bin'-type turret equipped with one or two hand-operated machine-guns. The Junkers Ju 86 and Handley Page Heyford under turrets were examples of the current design thinking at this time, providing defence from fighter attack from below. A development contract was awarded to Parnall for a suitable design incorporating the Frazer-Nash hydraulic system.
The Parnall designers found that the main problem was excess weight: hydraulic rams and valve boxes had to be provided for both turret operation and retraction, and the main frame had to be sufficiently strong to withstand the pressure of the slipstream and the considerable weight of controls, guns and ammunition and, of course the gunner.
The resulting design consisted of a circular drum attached to an inner turret ring which revolved on roller bearings running in a fixed outer ring, rotated by a hydraulic motor mounted on the inner ring. The outer ring was attached to a cylindrical superstructure which was raised or lowered between guide bars in the fuselage.The turret was raised and lowered by hydraulic rams connected at their lower ends to the guide bars and at their upper ends to the superstructure.
The operating sequence was as follows: the gunner in the fuselage extended the turret by moving a lever which actuated the retraction rams. When it was fully extended he crouched between the two steadying beams and, using the tread plates provided carefully stepped down into his small seat. As the seat was fixed to the base of the turret, he then extended the footwell by winding a small handle fixed in the centre of an instrument panel to his front. He then lowered his legs into it. The reflector sight was then switched on, being fixed on a gimbal ring, attached to a radius arm which moved in harmony with the guns. The two 7.7 mm (0.303 in) Browning guns were mounted in cradles, one on each side of the turret, and pivoted on bearings fitted on stiff brackets secured to the inner turret ring and actuated by rams. Ammunition was carried in two 500 round boxes in the top of the turret, fed into the breeches by chutes. Having connected his oxygen supply he cocked the guns and was ready for action. To his front was a narrow Perspex window running from top to bottom, but it was only 152 mm (6 in) wide. There were also side windows, but as these were cut into the frame only where there was no interference from equipment, the gunner's vision was far from ideal.
In theory the aircraft was now provided with a power-operated under turret, with complete 360 degrees traverse, ready to deal with attack from below. In practice, however, the turret was seldom used. The basic flaw in the whole design concept was that when a bomber was under attack, the extended turret slowed the aircraft's speed by 17-33 kph (10-20 mph), and this, coupled with the questionable visibility of the gunner, led the crews to decide that the turret was more of a liability than an asset.
Another rather serious fault with the FN.17 was the tendency of the turret to extend unintentionally during flight. This was caused by hydraulic valve 'creep' and several serious landing accidents were caused by this fault.
The FN.17 was installed in the early production Whitley Mks. I, II, III & IV, but due to the reasons stated, was soon taken out by operational squadrons. The turrets were not installed in any Whitleys after the Mk.IV. When the Whitley became obsolescent as a bomber it was used extensively for paratroop and supply dropping, and the circular hole previously used by the turret proved an ideal exit for this purpose. For this reason all production Whitleys retained the turret hole in the fuselage floor.
Details of the Nash and Thompson FN.17 Mid-under Turret.
Position in aircraft: Mid-under
Motive power: Hydraulic from engine-driven pump
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 500 rounds per gun
Gunsight: Mk.IIIA free mounted gun sight
Fire control: Palmer hydraulic
Field of fire:
Traverse: 360 degrees
Elevation (max): 6 degrees
Depression: 50 degrees
Weight of turret (empty): 168 kg (370 lb)
Weight of turret with guns and ammunition: 325 kg (715 lb)
Diameter of ring: 87 cm (34 in)
Hydraulic working pressure: 22 kg/sq cm (300 lb/sq in)
Armour: None
The following aircraft were fitted with the Nash and Thompson FN.17 Mid-under Turret.
Aircraft type: Armstrong Whitworth Whitley Mks. I , II, II and IV
Type & Mark: FN.17
Position: Mid-under
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 6 degrees
Depression: 50 degrees
Remarks:
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.18 Mid-upper Turret.
This was a design only.
The Nash and Thompson Type FN.19 Mid-under Turret
This mid-under turret was fitted with 2 x 7.7 mm Browning Mk.II and was intended for the Short Stirling. Prototype only.
The Nash and Thompson Type FN.20 Tail Turret
This turret was the most important of the Parnall range, providing rear defence for most of the aircraft of Bomber Command. The designers at Tolworth had been asked to redesign the FN.4, incorporating modifications suggested by Gunnery Leaders on the squadrons. An armoured shield was fitted, and the gunner was provided with a clear-vision panel, but the main improvement was in the ammunition supply. The ammunition boxes in the FN.4 were fitted in the turret under the guns, which limited the supply and affected the trim of the aircraft. A new supply system was devised in which large capacity boxes were fixed to the sides of the rear fuselage, the ammunition belts being taken from the boxes along steel tracks to the base of the turret.
Entering at the base by way of rotating right-angle elbow joints, they were taken through ammunition booster units. These were needed because by the time the belts had reached the guns the weight was far too heavy to be pulled into the breeches by the gun feed mechanisms. The FN servo feed units were an ingenious design in which powered sprockets were automatically energised when the belt pull was more than the gun feeds could handle.
The servo feed unit was driven by a hydraulic motor, two pipes connecting it to the pressure and exhaust lines of the turret feed system. The drive was transferred to the sprockets by four friction clutches. When the guns commenced firing, the belts between the sprockets and the guns tightened, and the platen arms moved across, engaging the clutches. If a belt jammed, an overload device disengaged its clutch. When the obstruction was cleared the clutch could be re-engaged by hand.
Three 9 mm (0.354 in) armour plates, hinged horizontally and moving in unison with the guns in elevation, afforded protection to the gunner's front. The armour affected the gunner's field of view, and also limited the amount of ammunition that could be carried on some long-distance sorties because of its weight. Some Groups decided that rather than set out on a long trip with less than a full supply of ammunition, a better weight-saving idea was to dispense with the armour.
In common with most turrets, when operating at the very low temperatures encountered on night operations, the gunner's view was often restricted by misting and frost glazing the cupola. It was not uncommon for a gunner to smash the Perspex front panel to give a better field of view. Although this added to his physical discomfort it was thought that the clear view was well worth a few degrees' drop in temperature. The removal of the front panel soon became widespread, leading to an official modification to turrets coming off the line at Yate. The front panel was then mounted in side grooves, allowing it to be dropped to give a clear view to the front.
The gunner entered the FN.20 from the fuselage. After clipping his parachute to quick-release hooks just inside the turret, he climbed into his seat and closed the sliding doors behind him, securing the locking catch. On early models of the turret, during violent manoeuvres the catch sometimes gave way, allowing the doors to slide open. Without a backrest the gunner fell back into the fuselage and regained his position only with great difficulty. The catch was redesigned and strengthened.
The turret controls were basically the same as in all Parnall tail turrets, with some modifications.
The triggers on the twin-handled control column operated the four Palmer hydraulically gun-firing valves via Bowden Cables. On some experimental FN.20s used on high-altitude operations, the triggers operated electrical switches controlling relays. The four Browning guns were harmonised to a point 229 m (250 yds) distant on to a 3 m (7ft 6 in) square for night operations, and 366 m (400 yds) on a 2 m (5 ft) square for daylight sorties. The FN.20 turret was popular with gunners, and, apart from the clear-view panel and door catch, few modifications were needed.
All the usual ancillary services were fitted to the turret. Provision was made for observing the angle of drift to assist the navigator, and a more efficient form of oxygen supply was installed. This consisted of an oxygen economiser which regulated the supply to the gunner according to demand. Problems had occurred with the old Type E oxygen masks, and a new mask, Type G, was issued at the time of the introduction of the FN.20. This mask fitted the Type B helmet, and few problems were encountered with the oxygen equipment after this.
The gunner could abandon the aircraft by opening the doors, grabbing and clipping on his parachute, traversing the turret to the beam stops, pulling the pin from his seat harness and falling out backwards. In the event of the gunner being injured, another member of the crew could release the door catch from the fuselage, and there was also a manually operated hydraulic valve outside the turret which enabled the turret to be turned from outside. This facility was added after injured gunners had been trapped inside with fatal consequences. If the hydraulic supply failed, the gunner could turn the turret by disengaging the rotation drive and turning a handle which operated a pinion acting on the gear teeth of the fixed turret ring.
When the Wellington Mk.VI high-altitude bomber was being designed Parnall were asked to provide a pressurised tail turret which was to be known as the Type FN.70, but it was soon found that such a project would need new technology, and the time needed was not available. The Wellington Mk.VI was eventually fitted with a remotely controlled FN.20 turret sighted from a dome in the pressure cabin.
In late 1944 a modified FN.20 was introduced and, as this incorporated new parts, it was designated the Type FN.120. The weight was reduced by 18 kg (40 lb) and some of the main structural members were redesigned. The most popular feature from the gunner's point of view was an improved heating system.
Details of the Type FN.20 Tail Turret
Position in aircraft: Tail
Motive power: Hydraulic motor
Armament: Four 7.7 mm (0.3030 in) Browning Mk.II guns
Ammunition: 2,500 rounds per gun; 1,900 in fuselage boxes, 600 in feed tracks
Ammunition feed: FN hydraulic servo feed from fuselage boxes
Gunsight: Mk.III free mounted reflector sight; Mk.IIC gyro gunsight
Fire control: Palmer electric
Field of view:
Traverse: 94 degrees to each beam
Elevation: 60 degrees
Depression: 45 degrees
Weight of turret (empty): 148 kg (325 lb)
Weight (operational): 614 kg (1,350 lb) = gunner - 82 kg (180 lb); guns - 40 kg (88 lb); ammo - 218 kg (480 lb); boxes - 15 kg (33 lb); tracking - 23 kg (50 lb)
Diameter of ring: (30 1/2 in)
Armour (when fitted): 9 mm (0.354 in) armoured plates to front aspect
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.18 Mid-upper Turret.
This was a design only.
The Nash and Thompson Type FN.19 Mid-under Turret
This mid-under turret was fitted with 2 x 7.7 mm Browning Mk.II and was intended for the Short Stirling. Prototype only.
The Nash and Thompson Type FN.20 Tail Turret
This turret was the most important of the Parnall range, providing rear defence for most of the aircraft of Bomber Command. The designers at Tolworth had been asked to redesign the FN.4, incorporating modifications suggested by Gunnery Leaders on the squadrons. An armoured shield was fitted, and the gunner was provided with a clear-vision panel, but the main improvement was in the ammunition supply. The ammunition boxes in the FN.4 were fitted in the turret under the guns, which limited the supply and affected the trim of the aircraft. A new supply system was devised in which large capacity boxes were fixed to the sides of the rear fuselage, the ammunition belts being taken from the boxes along steel tracks to the base of the turret.
Entering at the base by way of rotating right-angle elbow joints, they were taken through ammunition booster units. These were needed because by the time the belts had reached the guns the weight was far too heavy to be pulled into the breeches by the gun feed mechanisms. The FN servo feed units were an ingenious design in which powered sprockets were automatically energised when the belt pull was more than the gun feeds could handle.
The servo feed unit was driven by a hydraulic motor, two pipes connecting it to the pressure and exhaust lines of the turret feed system. The drive was transferred to the sprockets by four friction clutches. When the guns commenced firing, the belts between the sprockets and the guns tightened, and the platen arms moved across, engaging the clutches. If a belt jammed, an overload device disengaged its clutch. When the obstruction was cleared the clutch could be re-engaged by hand.
Three 9 mm (0.354 in) armour plates, hinged horizontally and moving in unison with the guns in elevation, afforded protection to the gunner's front. The armour affected the gunner's field of view, and also limited the amount of ammunition that could be carried on some long-distance sorties because of its weight. Some Groups decided that rather than set out on a long trip with less than a full supply of ammunition, a better weight-saving idea was to dispense with the armour.
In common with most turrets, when operating at the very low temperatures encountered on night operations, the gunner's view was often restricted by misting and frost glazing the cupola. It was not uncommon for a gunner to smash the Perspex front panel to give a better field of view. Although this added to his physical discomfort it was thought that the clear view was well worth a few degrees' drop in temperature. The removal of the front panel soon became widespread, leading to an official modification to turrets coming off the line at Yate. The front panel was then mounted in side grooves, allowing it to be dropped to give a clear view to the front.
The gunner entered the FN.20 from the fuselage. After clipping his parachute to quick-release hooks just inside the turret, he climbed into his seat and closed the sliding doors behind him, securing the locking catch. On early models of the turret, during violent manoeuvres the catch sometimes gave way, allowing the doors to slide open. Without a backrest the gunner fell back into the fuselage and regained his position only with great difficulty. The catch was redesigned and strengthened.
The turret controls were basically the same as in all Parnall tail turrets, with some modifications.
The triggers on the twin-handled control column operated the four Palmer hydraulically gun-firing valves via Bowden Cables. On some experimental FN.20s used on high-altitude operations, the triggers operated electrical switches controlling relays. The four Browning guns were harmonised to a point 229 m (250 yds) distant on to a 3 m (7ft 6 in) square for night operations, and 366 m (400 yds) on a 2 m (5 ft) square for daylight sorties. The FN.20 turret was popular with gunners, and, apart from the clear-view panel and door catch, few modifications were needed.
All the usual ancillary services were fitted to the turret. Provision was made for observing the angle of drift to assist the navigator, and a more efficient form of oxygen supply was installed. This consisted of an oxygen economiser which regulated the supply to the gunner according to demand. Problems had occurred with the old Type E oxygen masks, and a new mask, Type G, was issued at the time of the introduction of the FN.20. This mask fitted the Type B helmet, and few problems were encountered with the oxygen equipment after this.
The gunner could abandon the aircraft by opening the doors, grabbing and clipping on his parachute, traversing the turret to the beam stops, pulling the pin from his seat harness and falling out backwards. In the event of the gunner being injured, another member of the crew could release the door catch from the fuselage, and there was also a manually operated hydraulic valve outside the turret which enabled the turret to be turned from outside. This facility was added after injured gunners had been trapped inside with fatal consequences. If the hydraulic supply failed, the gunner could turn the turret by disengaging the rotation drive and turning a handle which operated a pinion acting on the gear teeth of the fixed turret ring.
When the Wellington Mk.VI high-altitude bomber was being designed Parnall were asked to provide a pressurised tail turret which was to be known as the Type FN.70, but it was soon found that such a project would need new technology, and the time needed was not available. The Wellington Mk.VI was eventually fitted with a remotely controlled FN.20 turret sighted from a dome in the pressure cabin.
In late 1944 a modified FN.20 was introduced and, as this incorporated new parts, it was designated the Type FN.120. The weight was reduced by 18 kg (40 lb) and some of the main structural members were redesigned. The most popular feature from the gunner's point of view was an improved heating system.
Details of the Type FN.20 Tail Turret
Position in aircraft: Tail
Motive power: Hydraulic motor
Armament: Four 7.7 mm (0.3030 in) Browning Mk.II guns
Ammunition: 2,500 rounds per gun; 1,900 in fuselage boxes, 600 in feed tracks
Ammunition feed: FN hydraulic servo feed from fuselage boxes
Gunsight: Mk.III free mounted reflector sight; Mk.IIC gyro gunsight
Fire control: Palmer electric
Field of view:
Traverse: 94 degrees to each beam
Elevation: 60 degrees
Depression: 45 degrees
Weight of turret (empty): 148 kg (325 lb)
Weight (operational): 614 kg (1,350 lb) = gunner - 82 kg (180 lb); guns - 40 kg (88 lb); ammo - 218 kg (480 lb); boxes - 15 kg (33 lb); tracking - 23 kg (50 lb)
Diameter of ring: (30 1/2 in)
Armour (when fitted): 9 mm (0.354 in) armoured plates to front aspect
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
Hi
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.21 Ventral Turret
When the second prototype Avro Manchester took to the air on 26 May, 1940 it was armed with three Parnall turrets which, it was hoped, would provide it with all-round defence. Attack from below and abeam was covered by a new ventral turret, the Type FN.21.
With the tense international situation, production of the Manchester had been pushed through in 1938, before the prototype had flown, and production of the turrets at Yate was given high priority. When Manchesters reached the squadrons in late 1940 they were fitted with cumbersome under defence turrets similar to those originally used on the first production Wellingtons and Whitleys, which had been consigned to the station scrapyards. During the trials of the second prototype at Boscombe Down, armament experts had cast doubt on the value of the ventral turret. It weighed a quarter of a ton, and slowed the aircraft by (15 mph) when extended. The big Rolls-Royce engines of the Manchester proved to be nearly as great a threat to the aircrew as German flak or fighters, the X-type arrangement of the 24 cylinders proving a problem for the cooling, lubrication and, above all, con-rod big ends.
The first major modification made to No.27 Squadron's Manchesters at Waddington was the removal of the ventral turret and new aircraft soon appeared with a new mid-upper turret to take care of beam attacks, the FN.7.
The FN.21A
The FN.21A, designed after the FN.9 and 17, gave the gunner a much improved field of view. There were three windows to the front and a square window low to each beam. It was retracted into the fuselage by side-mounted hydraulic jacks. If a loss of hydraulic power occurred it could be raised (very slowly) by means of a manual pump. The gunner operated the hydraulic lowering valves, extending it into the slipstream, producing a whining noise and a marked change of trim. He then stepped into the turret , taking great care not to touch the turret jettison lever, and lowered the two foot-wells at the bottom. Oxygen and intercom connections were provided on a small panel to his front, and a trainable floodlight could be used for stoppage clearance. The usual Nash and Thompson twin handle controller was used, triggers on each handle firing both guns.
The turret was suspended on ball bearings, and rotated by a hydraulic motor, two hydraulic rams moving the guns in elevation. Ammunition belts were routed from boxes on top of the turret via swan-necked chutes into the receivers of the two Browning guns.
Getting into these turrets was quite a daunting experience, especially at night. They were draughty and very cold, and it was, according to one gunner, like getting into a refrigerator with the lights out.
The time and effort exerted on the FN.21A in 1938-39 was largely wasted, although there was no way of knowing in those hectic days that the theory which led to the specification was flawed. By 1943 it was belatedly being realised that night fighters attacked from below.
Details of the Nash and Thompson FN.21 and FN.21A Ventral Turret
Position in aircraft: Ventral
Power system: Nash and Thompson hydraulic systemj from EDP
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 500 round per gun
Gunsight: Mk.IIIA reflector sight
Fire control: Palmer hydraulic
Field of fire:
Traverse: 360 degrees
Elevation: 25 degrees
Depression: 90 degrees
Weight (Empty): 120 kg (265 lb)
Diameter of turret: 90.17 cm (35.5 in)
Quantity of oil in system: 18.2 litres (4 Imp gal)
The Nash and Thompson FN.21 and FN.21A Ventral Turret was used by the following aircraft.
Aircraft Type: Avro Manchester
Type & Mark: FN.21A
Position: Mid-under
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 25 degrees
Depression: 90 degrees
Remarks:
FN22
Experimental Only.
FN23 & FN24
Both cancelled at an early stage.
Nash and Thompson FN25 Ventral Turret
When the Air Staff realised that the Vickers gun positions of the Wellington Mk.I were not a success, Parnall was asked to submit designs for three new turrets to rearm the aircraft. One of these was to be an under defence turret which could be fully retracted into the fuselage when not in use.
The specification was similar to the FN17 Whitley under defence turret, and the resulting design was virtually identical. In theory the turret, designated the FN25, fulfilled every requirement of it. the gunner lowered himself into the enclosure after extending the turret into the slipstream, and a hand-operated footwell was extended through the base of the turret, providing leg room for the gunner when seated. Using the twin-handle controller he was able to turn the turret a full 360 degrees and depress the two 7.7 mm (0.303 in) Brownings to 50 degrees below horizontal. The turret was of a cylindrical shape, and owing to the need for rigidity it was not possible to provide extensive glazing, but the seated gunner nevertheless had a reasonable view to his front through a long narrow window. The designers managed to incorporate all the retraction and operating hydraulics within the turret housing. The prototype was completed, installed in a Wellington Mk.I and flown to Boscombe Down for evaluation.
The trials team had reservations about the gunner's field of view, and noted the difficulty in following a fast-moving target, but a fighter climbing to attack from below could be easily engaged. In view of the essential need to protect the lower hemisphere from attack, the FN25 was accepted for use and a production order issued. it must be remembered that in 1938 it was envisaged that formations of bombers would be used by day protected by concentrated fire from the many power operated turrets.
When the Wellington Mk.I reached the squadrons, however, gunners soon formed the opinion that the FN25 was virtually useless. A report from No.9 Sqd, based at Honington, in 1940 stated that the FN25 was more of a liability than an asset - when extended it slowed tha aircraft by 16 Km (10 mph), and visibility through the narrow sighting window was totally inadequate to follow an intercepting fighter. There had also been occasions when the turret had frozen in the down position, making it necessary to jettison it. The FN25 soon joined the Whitley and Manchester ventral turrets on the scrap-heaps, and after the first batch of Wellington Mk.IAs it was not fitted. Production was terminated, and the unused turrets were put in store. Two years later they were adapted for the retractable form of anti-submarine Leigh Lights.
The turret consisted of a circular drum attached to an inner ring which revolved on roller bearings running in a fixed outer ring. It was lowered from the fuselage by means of a hydraulic double-acting ram. A hydraulic motor on the inner ring provided the rotational drive through a pinion engaging with a circular gear track secured to the outer ring. two large steadying beams connected by a torque shaft were linked to the moving section of the turret, to overcome juddering during turret extension or retraction. two 7.7 mm (0.303 in) Browning guns were mounted in cradles, one each side of the gunner, pivoting in brackets secured to the inner ring. The Mk.III reflector sight was as usual arranged to elevate or depress with the guns. Hydraulic power was obtained from a pump on the port engine: this supplied oil to a rotating service joint on the bridge connecting the guide bars, and thence to the valve box.
The gunner was supplied with oxygen and an intercom link. he could retract the turret by a hand pump in emergency, or jettison it by a lever. Gunners stepping into the enclosure on a dark night had to be careful not to kick the lever.
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
The Nash and Thompson Engineering Company
The Nash and Thompson Type FN.21 Ventral Turret
When the second prototype Avro Manchester took to the air on 26 May, 1940 it was armed with three Parnall turrets which, it was hoped, would provide it with all-round defence. Attack from below and abeam was covered by a new ventral turret, the Type FN.21.
With the tense international situation, production of the Manchester had been pushed through in 1938, before the prototype had flown, and production of the turrets at Yate was given high priority. When Manchesters reached the squadrons in late 1940 they were fitted with cumbersome under defence turrets similar to those originally used on the first production Wellingtons and Whitleys, which had been consigned to the station scrapyards. During the trials of the second prototype at Boscombe Down, armament experts had cast doubt on the value of the ventral turret. It weighed a quarter of a ton, and slowed the aircraft by (15 mph) when extended. The big Rolls-Royce engines of the Manchester proved to be nearly as great a threat to the aircrew as German flak or fighters, the X-type arrangement of the 24 cylinders proving a problem for the cooling, lubrication and, above all, con-rod big ends.
The first major modification made to No.27 Squadron's Manchesters at Waddington was the removal of the ventral turret and new aircraft soon appeared with a new mid-upper turret to take care of beam attacks, the FN.7.
The FN.21A
The FN.21A, designed after the FN.9 and 17, gave the gunner a much improved field of view. There were three windows to the front and a square window low to each beam. It was retracted into the fuselage by side-mounted hydraulic jacks. If a loss of hydraulic power occurred it could be raised (very slowly) by means of a manual pump. The gunner operated the hydraulic lowering valves, extending it into the slipstream, producing a whining noise and a marked change of trim. He then stepped into the turret , taking great care not to touch the turret jettison lever, and lowered the two foot-wells at the bottom. Oxygen and intercom connections were provided on a small panel to his front, and a trainable floodlight could be used for stoppage clearance. The usual Nash and Thompson twin handle controller was used, triggers on each handle firing both guns.
The turret was suspended on ball bearings, and rotated by a hydraulic motor, two hydraulic rams moving the guns in elevation. Ammunition belts were routed from boxes on top of the turret via swan-necked chutes into the receivers of the two Browning guns.
Getting into these turrets was quite a daunting experience, especially at night. They were draughty and very cold, and it was, according to one gunner, like getting into a refrigerator with the lights out.
The time and effort exerted on the FN.21A in 1938-39 was largely wasted, although there was no way of knowing in those hectic days that the theory which led to the specification was flawed. By 1943 it was belatedly being realised that night fighters attacked from below.
Details of the Nash and Thompson FN.21 and FN.21A Ventral Turret
Position in aircraft: Ventral
Power system: Nash and Thompson hydraulic systemj from EDP
Armament: Two 7.7 mm (0.303 in) Browning Mk.II guns
Ammunition: 500 round per gun
Gunsight: Mk.IIIA reflector sight
Fire control: Palmer hydraulic
Field of fire:
Traverse: 360 degrees
Elevation: 25 degrees
Depression: 90 degrees
Weight (Empty): 120 kg (265 lb)
Diameter of turret: 90.17 cm (35.5 in)
Quantity of oil in system: 18.2 litres (4 Imp gal)
The Nash and Thompson FN.21 and FN.21A Ventral Turret was used by the following aircraft.
Aircraft Type: Avro Manchester
Type & Mark: FN.21A
Position: Mid-under
Guns: 2 x 7.7 mm (0.303 in) Browning Mk.II
Traverse: 360 degrees
Elevation: 25 degrees
Depression: 90 degrees
Remarks:
FN22
Experimental Only.
FN23 & FN24
Both cancelled at an early stage.
Nash and Thompson FN25 Ventral Turret
When the Air Staff realised that the Vickers gun positions of the Wellington Mk.I were not a success, Parnall was asked to submit designs for three new turrets to rearm the aircraft. One of these was to be an under defence turret which could be fully retracted into the fuselage when not in use.
The specification was similar to the FN17 Whitley under defence turret, and the resulting design was virtually identical. In theory the turret, designated the FN25, fulfilled every requirement of it. the gunner lowered himself into the enclosure after extending the turret into the slipstream, and a hand-operated footwell was extended through the base of the turret, providing leg room for the gunner when seated. Using the twin-handle controller he was able to turn the turret a full 360 degrees and depress the two 7.7 mm (0.303 in) Brownings to 50 degrees below horizontal. The turret was of a cylindrical shape, and owing to the need for rigidity it was not possible to provide extensive glazing, but the seated gunner nevertheless had a reasonable view to his front through a long narrow window. The designers managed to incorporate all the retraction and operating hydraulics within the turret housing. The prototype was completed, installed in a Wellington Mk.I and flown to Boscombe Down for evaluation.
The trials team had reservations about the gunner's field of view, and noted the difficulty in following a fast-moving target, but a fighter climbing to attack from below could be easily engaged. In view of the essential need to protect the lower hemisphere from attack, the FN25 was accepted for use and a production order issued. it must be remembered that in 1938 it was envisaged that formations of bombers would be used by day protected by concentrated fire from the many power operated turrets.
When the Wellington Mk.I reached the squadrons, however, gunners soon formed the opinion that the FN25 was virtually useless. A report from No.9 Sqd, based at Honington, in 1940 stated that the FN25 was more of a liability than an asset - when extended it slowed tha aircraft by 16 Km (10 mph), and visibility through the narrow sighting window was totally inadequate to follow an intercepting fighter. There had also been occasions when the turret had frozen in the down position, making it necessary to jettison it. The FN25 soon joined the Whitley and Manchester ventral turrets on the scrap-heaps, and after the first batch of Wellington Mk.IAs it was not fitted. Production was terminated, and the unused turrets were put in store. Two years later they were adapted for the retractable form of anti-submarine Leigh Lights.
The turret consisted of a circular drum attached to an inner ring which revolved on roller bearings running in a fixed outer ring. It was lowered from the fuselage by means of a hydraulic double-acting ram. A hydraulic motor on the inner ring provided the rotational drive through a pinion engaging with a circular gear track secured to the outer ring. two large steadying beams connected by a torque shaft were linked to the moving section of the turret, to overcome juddering during turret extension or retraction. two 7.7 mm (0.303 in) Browning guns were mounted in cradles, one each side of the gunner, pivoting in brackets secured to the inner ring. The Mk.III reflector sight was as usual arranged to elevate or depress with the guns. Hydraulic power was obtained from a pump on the port engine: this supplied oil to a rotating service joint on the bridge connecting the guide bars, and thence to the valve box.
The gunner was supplied with oxygen and an intercom link. he could retract the turret by a hand pump in emergency, or jettison it by a lever. Gunners stepping into the enclosure on a dark night had to be careful not to kick the lever.
The above text and photos were taken from "British Aircraft Armament Vol.1: RAF Gun Turrets", by R Wallace Clarke.
Regards
Bob
You do not have the required permissions to view the files attached to this post.
-
Robert Hurst
- Member
- Posts: 1192
- Joined: 04 Oct 2002 15:11
- Location: Worksop, Notts, UK
The Nash and Thompson Type FN25 Under Turret
Details of the Nash and Thompson FN25 Under Turret
Position: Mid-Under
Motive power: Engine driven pump
Armament: Two 7.7 mm (0.303 in) Browning Mk.II
Ammuntion: 500 rounds per gun.
Gunsight: Mk.IIIA reflector Sight.
Fire control: Palmer hydraulic.
Field of Fire:
Traverse: 360 degrees
Elevation: 5 degrees
Depression: 50 degrees.
Diameter of ring: 91.44 cm (36 in)
Working pressure: 21 Kg/Sq C (300 lb/sq ft)
Weight of turret (empty) 172 Kg (380 lb)
The following type of aircraft was fitted with the FN25 Under Turret
Aircraft Type: Vickers Wellington Mk.IA
Type and Mark: FN25
Position: Under fuselage turret
Guns: Two 7.7 mm (0.303 in) Browning Mk.2
Traverse: 360 degrees
Elevation: 5 degrees
Remarks: Similar to FN17
Depression: 50 degrees
The Nash and Thompson FN26 Nose Turret
Details of the FN 26 Nose Turret
Position: Nose
Armament: One 7.7 mm (0.303 in) Vickers K
Ammunition: 1,000 rounds
Weight: 249 kg (550 lb)
The following type of aircraft was fitted with the FN26 Nose Turret
Aircraft type: Saro Lerwick
Type and Mark: FN26
Position: Nose
Guns: One 7.7 mm (0.303 in) Vickers K
Traverse:
Elevation:
Depression:
Remarks: Similar to FN12
The Nash and Thompson FN27 Mid-upper Turret
Details of the FN27 Mid-upper Turret
Position: Mid-upper
Armament: Two 20 mm (0.79 in) Hispano cannon
Ammunition: 600 rounds per gun
Weight: 750 kg (1,654 lb)
Aircraft: Bomber
Type and Mark: FN27
Position: Mid-upper
Guns: Two 20 mm (0.79 in) Hispano Cannon
Traverse:
Elevation:
Depression;
Remarks: Experimental only.
The Nash and Thompson Types FN28 and FN29 Mid-upper and Mid-under Turrets
Two rather obscure turrets designed by Parnall were the FN29 and FN29. Designed for the Avro Lancaster, they were to be armed with twin 20 mm (0.79 in) cannon. These new weapons were apparently designed by the Birmingham Small Arms company which was asked to copy the German 20 mm (0.79 in) MG151 Mauser cannon for use by RAF. The MAP gun section was responsible for all new RAF weapons. It was led by Capt H S V Thompson until succeeded by Mr G F Wallace. The full title of the section was Gun Section of the Directorate of Armament Development. Professor Lindemann, the Prime Minister's scientific adviser, voiced his total oppposition to the adoption of the gun. He pointed out that the action of the gun was such that a round was retained in the breech after firng ceased, and whereas german nitro-filled ammuntion was quite safe, British cordite rounds were bound to 'cook off' or detonate in the hot breech, as was experienced with the American Browning gun before it was redesigned by capt W S V Adams of the MAP gun section. Professor Lindemann's view prevailed and the designs were not proceeded with.
Details of the FN28 Mid-upper and FN29 Mid-under Turrets
Position:
FN28: Mid-upper Turret
FN29 Mid-under Turret
Armament:
FN28: 20 mm (0.79 in) Mauser MG151 cannon
FN29: 20 mm (0.79 in) Hispano cannon
Ammunition:
FN28: 480 rounds per gun
FN29: 120 rounds per gun
Weight:
FN28 962 kg (2,121 lb)
FN29: 757 kg (1,670 lb)
The following aircraft was to be fitted with the FN28 Mid-upper and FN29 Mid-under Turret
Aircraft Type: Avro Lancaster
Type and Mark: FN28 and FN29
Position:
FN28 Mid-upper Turret
FN29 Mid-under Turret
Guns:
FN28: Two 20 mm (0.79 in) Mauser MG151
FN29: Two 20 mm (0.79 in) Hispano
Remarks:
Traverse:
Elevation:
Depression:
Remarks:
FN28: design only
FN29: experimental only
The Nash and Thompson FN30 Mid-upper Turret
The only details of the FN30 Mid-upper turret are as follows.
Aircraft type: Bomber
Type and Mark: FN30
Position: Mid-upper
Guns: Four 7.7 mm (0.303 in) Browning
Ammunition: 150 rounds per gun
Weight: 1,234 kg (2,720 lb)
Remarks: Experimental only
The Nash and Thompson FN31 Mid-under Turret
The only details for the FN31 Mid-uner Turret are as follows.
Aircraft Type: Bomber
Position: Mid-under
Guns: Four 20 mm (0.79 in) Hispano cannon
Ammunition: 150 rounds per gun
Weight: 1,179 kg (2,600 lb)
Remarks:
The Nash and Thompson FN32 Turret
The only details of the FN32 Turret are as follows.
Aircraft Type:
Position:
Guns:
Ammunition:
Weight:
Remarks: Cancelled at design stage.
The Nash and Thompson FN33 Mid-upper Turret
The only details of the FN33 Mid-upper Turret are as follows.
Aircraft Type: Bomber
Position: Mid-upper
Guns: Four 7.7 mm (0.303 in) Browning Mk.II
Ammunition: 1,000 round per gun.
Weight: 499 kg (1,100 lb)
Remarks: Experimental only.
The Nash and Thompson FN34 Mid-upper Turret.
The only Details of the FN34 Mid-upper Turret are as follows.
Aircraft Type: Bomber
Position: Mid-upper
Guns: One 7.7 mm (0.303 in) Browning Mk.II
Ammunition:
Weight:
Remarks: Experimental only.
The Nash and Thompson FN35 Mid-upper Turret
The only details of the FN35 Mid-upper Turret are as follows.
Aircraft Type: Bomber
position: Mid-upper
Guns: 2 7.7 mm (0.303 in) Browning Mk.II
Ammunition: 1,000 rounds per gun
Weight: 317 kg (700 lb)
Remarks: Experimental only.
The Nash and Thompson FN36 Mid-upper Turret
The only of the FN36 Mid-upper Turret are as follows.
Aircraft Type: Short Sunderland
Position: Mid-upper
Guns: Four 12.7 mm (0.50 in) Browning M2
Ammunition: 1,000 ropunds per gun
Weight: 944 kg (2,080 lb)
Remarks: Electro hydraulic. Cancelled early.
The Nash and Thompson FN38 Mid-upper Turret
The only details of the FN38 Mid-upper Turret are as follows.
Aircraft Type: Bomber
Position: Mid-upper
Guns: Two 12.7 mm (0.50 in) Browning M2
Ammunition: 500 rounds per gun
Weight: 712 kg (1,570 lb)
Remarks: Experimental only
Details of the Nash and Thompson FN25 Under Turret
Position: Mid-Under
Motive power: Engine driven pump
Armament: Two 7.7 mm (0.303 in) Browning Mk.II
Ammuntion: 500 rounds per gun.
Gunsight: Mk.IIIA reflector Sight.
Fire control: Palmer hydraulic.
Field of Fire:
Traverse: 360 degrees
Elevation: 5 degrees
Depression: 50 degrees.
Diameter of ring: 91.44 cm (36 in)
Working pressure: 21 Kg/Sq C (300 lb/sq ft)
Weight of turret (empty) 172 Kg (380 lb)
The following type of aircraft was fitted with the FN25 Under Turret
Aircraft Type: Vickers Wellington Mk.IA
Type and Mark: FN25
Position: Under fuselage turret
Guns: Two 7.7 mm (0.303 in) Browning Mk.2
Traverse: 360 degrees
Elevation: 5 degrees
Remarks: Similar to FN17
Depression: 50 degrees
The Nash and Thompson FN26 Nose Turret
Details of the FN 26 Nose Turret
Position: Nose
Armament: One 7.7 mm (0.303 in) Vickers K
Ammunition: 1,000 rounds
Weight: 249 kg (550 lb)
The following type of aircraft was fitted with the FN26 Nose Turret
Aircraft type: Saro Lerwick
Type and Mark: FN26
Position: Nose
Guns: One 7.7 mm (0.303 in) Vickers K
Traverse:
Elevation:
Depression:
Remarks: Similar to FN12
The Nash and Thompson FN27 Mid-upper Turret
Details of the FN27 Mid-upper Turret
Position: Mid-upper
Armament: Two 20 mm (0.79 in) Hispano cannon
Ammunition: 600 rounds per gun
Weight: 750 kg (1,654 lb)
Aircraft: Bomber
Type and Mark: FN27
Position: Mid-upper
Guns: Two 20 mm (0.79 in) Hispano Cannon
Traverse:
Elevation:
Depression;
Remarks: Experimental only.
The Nash and Thompson Types FN28 and FN29 Mid-upper and Mid-under Turrets
Two rather obscure turrets designed by Parnall were the FN29 and FN29. Designed for the Avro Lancaster, they were to be armed with twin 20 mm (0.79 in) cannon. These new weapons were apparently designed by the Birmingham Small Arms company which was asked to copy the German 20 mm (0.79 in) MG151 Mauser cannon for use by RAF. The MAP gun section was responsible for all new RAF weapons. It was led by Capt H S V Thompson until succeeded by Mr G F Wallace. The full title of the section was Gun Section of the Directorate of Armament Development. Professor Lindemann, the Prime Minister's scientific adviser, voiced his total oppposition to the adoption of the gun. He pointed out that the action of the gun was such that a round was retained in the breech after firng ceased, and whereas german nitro-filled ammuntion was quite safe, British cordite rounds were bound to 'cook off' or detonate in the hot breech, as was experienced with the American Browning gun before it was redesigned by capt W S V Adams of the MAP gun section. Professor Lindemann's view prevailed and the designs were not proceeded with.
Details of the FN28 Mid-upper and FN29 Mid-under Turrets
Position:
FN28: Mid-upper Turret
FN29 Mid-under Turret
Armament:
FN28: 20 mm (0.79 in) Mauser MG151 cannon
FN29: 20 mm (0.79 in) Hispano cannon
Ammunition:
FN28: 480 rounds per gun
FN29: 120 rounds per gun
Weight:
FN28 962 kg (2,121 lb)
FN29: 757 kg (1,670 lb)
The following aircraft was to be fitted with the FN28 Mid-upper and FN29 Mid-under Turret
Aircraft Type: Avro Lancaster
Type and Mark: FN28 and FN29
Position:
FN28 Mid-upper Turret
FN29 Mid-under Turret
Guns:
FN28: Two 20 mm (0.79 in) Mauser MG151
FN29: Two 20 mm (0.79 in) Hispano
Remarks:
Traverse:
Elevation:
Depression:
Remarks:
FN28: design only
FN29: experimental only
The Nash and Thompson FN30 Mid-upper Turret
The only details of the FN30 Mid-upper turret are as follows.
Aircraft type: Bomber
Type and Mark: FN30
Position: Mid-upper
Guns: Four 7.7 mm (0.303 in) Browning
Ammunition: 150 rounds per gun
Weight: 1,234 kg (2,720 lb)
Remarks: Experimental only
The Nash and Thompson FN31 Mid-under Turret
The only details for the FN31 Mid-uner Turret are as follows.
Aircraft Type: Bomber
Position: Mid-under
Guns: Four 20 mm (0.79 in) Hispano cannon
Ammunition: 150 rounds per gun
Weight: 1,179 kg (2,600 lb)
Remarks:
The Nash and Thompson FN32 Turret
The only details of the FN32 Turret are as follows.
Aircraft Type:
Position:
Guns:
Ammunition:
Weight:
Remarks: Cancelled at design stage.
The Nash and Thompson FN33 Mid-upper Turret
The only details of the FN33 Mid-upper Turret are as follows.
Aircraft Type: Bomber
Position: Mid-upper
Guns: Four 7.7 mm (0.303 in) Browning Mk.II
Ammunition: 1,000 round per gun.
Weight: 499 kg (1,100 lb)
Remarks: Experimental only.
The Nash and Thompson FN34 Mid-upper Turret.
The only Details of the FN34 Mid-upper Turret are as follows.
Aircraft Type: Bomber
Position: Mid-upper
Guns: One 7.7 mm (0.303 in) Browning Mk.II
Ammunition:
Weight:
Remarks: Experimental only.
The Nash and Thompson FN35 Mid-upper Turret
The only details of the FN35 Mid-upper Turret are as follows.
Aircraft Type: Bomber
position: Mid-upper
Guns: 2 7.7 mm (0.303 in) Browning Mk.II
Ammunition: 1,000 rounds per gun
Weight: 317 kg (700 lb)
Remarks: Experimental only.
The Nash and Thompson FN36 Mid-upper Turret
The only of the FN36 Mid-upper Turret are as follows.
Aircraft Type: Short Sunderland
Position: Mid-upper
Guns: Four 12.7 mm (0.50 in) Browning M2
Ammunition: 1,000 ropunds per gun
Weight: 944 kg (2,080 lb)
Remarks: Electro hydraulic. Cancelled early.
The Nash and Thompson FN38 Mid-upper Turret
The only details of the FN38 Mid-upper Turret are as follows.
Aircraft Type: Bomber
Position: Mid-upper
Guns: Two 12.7 mm (0.50 in) Browning M2
Ammunition: 500 rounds per gun
Weight: 712 kg (1,570 lb)
Remarks: Experimental only
You do not have the required permissions to view the files attached to this post.
-
Uncle Joe
- Banned
- Posts: 510
- Joined: 12 Oct 2004 20:09
- Location: Finland