At the time of the outbreak of World War II a wooden aircraft design was theoretically an anachronism, yet the DH.98 design would soon establish itself at the forefront of military aviation. De Havilland had a long experience with advanced wood construction techniques as applied in the DH.88 Comet and DH.91 Albatross. During the summer of 1938 De Havilland had started a study to develop the Albatross into a high speed bomber, The design, smaller than the Albatross in both fuselage and wing and to be powered by two Rolls Royce Merlin engines, would be able to carry a bomb load of 6,000lb to Berlin at such a high speed, that there was no need for any defensive armament. It was only after start of the German invasion of Poland in September 1939, that the design was subjected to official investigation by the Air Ministry. Although there was much debate on the need of self-protection for the new aircraft, on 29 December 1939, De Havilland was finally authorised to proceed with the development of the unarmed fast bomber design. At that time there was an equal interest in the Air Ministry for a photographic reconnaissance version.
Design work under the direction of R.E. Bishop, De Havilland's Chief Designer, gained pace and on 1 March 1940 De Havillands were awarded a contract for 50 bomber aircraft of the DH.98, the Mosquito.
The first prototype, serial W4050, was built in a small hangar near the DH design office at Salisbury Hall. After completion, it was transported to Hatfield and on 25 November 1940, made its first flight, only eleven months from the start of the design work, piloted by Geoffrey de Havilland Junior. Another two prototypes were constructed: W4051, the PR.I prototype and W4052 the F.II prototype. W4051 made her first flight on 10 June 1941 and was handed over to the Photographic Reconnaissance Unit at RAF Wick, Scotland, the following month. W4052, the night fighter prototype first flew on 15 May 1941.
The prototype for the first bomber version, the Mosquito B.IV made her maiden flight on 8 September 1941. The first Mosquito fighter-bomber version was developed from the NF.II night fighter. As the prototype for this new version, DZ434, a converted B.IV, was selected. It took to the air on 1 June 1942 and was delivered to the A&AEE at Boscombe Down on 13 June, where it was allocated serial HJ662/G.
HJ662/G crashed on 30 July 1942 on take-off from Boscombe Down due to failure of the port engine. The Mosquito was destroyed and two Beaufighters (R2311 and R2057) severely damaged. The Mosquito crew was injured.
DZ434 was replaced on the B.IV production line by a new aircraft with the same serial. This Mosquito was lost on 22 October 1943 during a night flying practice sortie. The No.109 Squadron aircraft crashed at Deeping St. Nicholas near Bourne in Lincolnshire. Of the Australian vrew, the pilot was killed and the navigator was thrown out of the aircraft and was able to use his parachute and land.
The Mosquito FB.VI was powered by two, single-stage two-speed, 1,460 hp (1,088 kW) Rolls Royce Merlin 21/23 or 1,635 hp (1,219 kW) Merlin 25 engines in the Series 2 aircraft. The Merlin 21 was a modified Merlin XX engine with the direction of the coolant flow reversed as needed for the wing radiator in the Mosquito. The Merlin 23 version was adapted in the same way from the Merlin 22.
Additional to the NF.II armament of four 0.303 in (7.7mm) Browning machine guns and four Hispanno Mk.II 20mm cannon, the FB.VI had the capacity to carry two 250lb (113.4 kg) bombs in the rear part of the bomb bay, the forward part of the bomb bay being occupied by the breeches and ammunition feeds of the Hispano cannon. Both parts of the bomb bay were covered by two pairs of doors. In the rear compartment two extra fuel tanks of 150 Imperial Gallon (682 litres) could be carried, instead of the bomb load.
For the intruder role a pair of additonal fuel tanks, each with a 25 Imperial Gallon capacity, could be fitted in the forward part of the bomb bay. (These tanks can be seen in TA122 on display at the De Havilland Aircraft Museum at London Colney).
The Series 1 aircraft had the same strenghtened wing as on the B.V in which the no.8 rib on each side was reinforced to carry a 50 Imp Gallon (227 litres) fuel drop tank or a 250lb bomb. The series 2 aicraft, with two Merlin 24 (1,635 hp / 1,219 kW), were capable of carrying two 500lb (226.8 kg) bombs internally and one of these under each wing. The bombs could be replaced by a 50 Imp Gallon (227 litres) fuel tank under each wing.
The wings were also wired to carry rocket projectiles. Up to four of these could be carried under each wing. The original racks of four rockets abreast were later modified to vertically placed pairs to allow external fuel tanks to be carried on the no.8 rib hardpoints, along with the rocket projectiles.
Mosquito FB.VI production*
The Mosquito FB.VI became to most produced variant with 2,313 examples built in the UK with 1,165 built at De Havilland at Hatfield. The Standard Motor Co Ltd at their Canley, Coventry works produced 1,066 and finally Airspeed Ltd at Christchurch with 82 FB.VI aircraft, the last six of these aircraft (VL726-VL732) officially designated as Mosquito FB.6.
De Havilland, Hatfield, Mosquito FB.VI production:
HJ662-HJ682 (with HJ662 being the prototype FB.VI; this was aircraft was built as B.IV DZ434).
HJ716-HJ743; HJ755-HJ792; HJ808-HJ833.
HX802-HX835; HX849-HX869, two aircraft in this block HX849 and HX850 collided during an air test on 23 August 1943 and crashed near St. Albans.
HX896-HX922, three aircradt, HX902, 903 and 904 converted to B.XVIII and not counted in the FB.VI production total.
HX937-HX984.
LR248-LR276; LR289-LR313; LR327-LR340; LR343-LR389; LR402-LR404.
MM398-MM431, with two (MM425 and 425) converted to B.XVIII and not counted in the FB.VI production total.
NS819-NS859; NS873-NS914; NS926-NS965; NS977-NS999.
NT112-NT156; NT169-NT207; NT219-NT239, with two (NT220 an NT224) converted to B.XVII and not counted in the FB.VI production total.
PZ161- PZ203; PZ217-PZ259; PZ273-PZ316; PZ330-PZ358; PZ371-PZ419; PZ435-PZ476. Nine aircraft (PZ251, 252, 300, 301, 346 and PZ467-470) were converted to FB.XVIII and not counted in the FB.VI production total.
RS501-RS535; RS548-RS580; RS593-RS633.
SZ958-SZ999.
TA113-TA122; TA369-TA388; TA469-TA508; TA523-TA560; TA575-TA603.
Standard Motor Mosquito FB.VI production:
HP848-HP888; HP904-HP942; HP967-HP989.
HR113-HR162; HR175-HR220; HR236-HR262; HR279-HR312; HR331-HR375; HR387-HR415; HR432-HR465; HR485-HR527; HR539-HR580; HR603-HR649.
RF580-RF625; RF639-RF681; RF695-RF736; RF749-RF793; RF818-RF859; RF873-RF915; RF928-RF966.
TE587-TE628; TE640-TE669; TE683-TE725; TE738-TE780; TE793-TE830; TE848-TE889; TE905-TE932.
Airspeed Mosquito FB.VI production:
RS637-RS680; RS693-RS698; RS699-RS723.
VL726-VL732 (these 7 aircraft officially designated FB.6).
*) The numbers of total Mosquito production vary from source to source. In some they are as high as 2,794, this number including (Canadian and Australian) variants based on the FB.VI. Other sources also include the number of cancelled production blocks.
The production figures given here are based on data from Air Britain's Royal Air force Aircraft serials books as well as Bruce Robertson's British Military Aircraft Serials 1912-1966 and his newer version (1878-1987), published in 1987 by Midland Counties.
Mosquito FB.VI Into service
The first production FB.VIs were delivered from 18 February 1943, with No.418 (City of Edmonton) Squadron, RCAF, based at RAF Ford, receiving the first examples on 7 May 1943. They started their first night and day intruder missions later that month.
Soon, from mid 1943 onwards, the Mosquito FB.VI would form the backbone of Bomber Command's No.2 Group and also, in the late summer of that year, the 2nd Tactical Air Force units Nos.21(RAF), 464(RAAF) and 487(RNZAF) Squadrons of No.140 Wing at RAF Sculthorpe re-equipped with the type. In October 1943 No.138 Wing was formed at RAF Lasham.
Preserved Mosquito FB.VI
In the USA, Mosquito FB.VI PZ474 (ex NZ2384) is currently the only airworthy FB.VI in the world. The machine was meticulously restored by AvSpecs Ltd at Ardmore aerodrome in New Zealand's North Island for Lewis Air Legends. The FB.VI was rolled out on 10 September 2018 and registered ZK-BCV made her first flight from Ardmore on 13 January 2019 in the hands of Steve Hinton with a very proud 'navigator' Warren Denholm on his side. With test flights completed, PZ474 was dismantled for shipment to the USA. In July 2019 PZ474 was one of the major stars of EAA AirVenture 2019 at Oshkosh, Wisconsin, where the project won two awards, the Phoenix Award and the Grand Champion WWII award, the latter being the most prestigious of all awards at the world’s biggest aviation event.
PZ474 is finished in a No.235 Squadron RAF Coastal Command scheme, with code '3-L'. This unit received their first FB.VIs in June 1944 and operated from RAF Portreath. In September of that year No.235 Squadron moved to Scotland to become part of the famous Banff Strike Wing.
In 2020 ownership of N474PZ was passed to Charles Somers and the aircraft is currently based at Sacramento.
Mosquito FB.VI TA122 is one of four Mosquitos at the De Havilland Aircraft Museum at London Colney in Hertfordshire. TA122 is in the colours of No.605 Squadron, RAF, and coded 'UP-G'. On 31 August 1945 this unit was re-numbered No.4 Squadron. TA122 retained her 605 code.
Star of the 'Dangerous Skies' Exhibition in the world-class Aviation Heritage Centre at Omaka, Blenheim, New Zealand, is Mosquito B.VI TE910. The Mosquito is one of the treasures from the late John Smith collection. Following his death in August 2019, the Smith family and the AHC have worked together closely to put this iconic former RNZAF aircraft on display.
TE910/NZ2336 is in the colours of 487 (New Zealand) Squadron, RAF, and represents B.VI NT131/EG-D. This machine was lost in the night of 4/5 July 1944, during a night intruder operation over France. NT131 was hit by anti-aircraft fire from the German air base at Avord and crashed in the early hours of 5 July near Camp d' Avord, some 18 kilometres ESE of the town of Bourges, France. Its crew, F/O Ronald Charles Ostend Beazer, RNZAF, and his navigator F/O Andrew White Munro, RAFVR, did not survive. They found their resting place in the Avord Communal Cemetery. During Classic Fighters 2023, The Mosquito had both her Merlin 25s running, each time attracting a huge audience.
- Country of Origin:
United Kingdom
- First Flight:
1 June 1942
- Initial Service Date:
May 1943
- No. Built:
2,313
- No. In Service:
0
- No. of Hardpoints:
2
- Crew:
2