Hatfield to Christchurch – Rebirth Of a Naval Fighter

During mid 1953 it was realised by the Admiralty that they were woefully lacking in a new all weather fighter design to replace the already outdated D.H.112 Sea Venom design then entering service, the Fairey N.14/48 had somehow lapsed and various DH.116 ‘Super Venom’ projects were becoming outdated. In late 1952 Specification N.139D was issued on behalf of the Navy calling for an all weather and low-level attack aircraft, suddenly the 110 was back in favour with their lordships, it had been originally designed for the earlier part of the role, was now well established through flight testing, and an airframe was immediately available.
WG240 was now set aside for minor FAA and carrier trials work and gained the then current Extra Dark Sea Grey and Sky finish, and more crucially redesigned and strengthened wings. It first flew in the new ‘naval’ layout on the 17 June 1953, again in the hands of Cunningham and Fairbrother, this wa sthe types first flight since the
In the following June it first flew with an all moving ‘all flying’ tailplane, becoming the first British type to be so equipped. The aircraft was also progressively modified to trial the various complex powered control & feel systems then being introduced aswel as differing wing modifications, such as drooped cambered leading edges and fences, to assist with low speed and approach handling, and Dunlop anti-skid braking – all vital for FAA use. Although the second 110 was used for Admiralty trials apart from the addition of longer stroke undercarriage units it was not navalised in any respect, however it did carry out ADDLs at RNAS Ford before conducting touch and go’s on HMS Albion with DH Christchurch’s chief test-pilot, Lt Cdr Jock Elliot in September 1954.

A semi navalised prototype was ordered in the short term, it wouldn’t feature folding wings, but did have the hooks and strengthened undercarriage to allow full stop and catapult take offs from a carrier. It was ordered in February 1954 and by late the same year the naval 110 became known as the Mk.20, this strangely (or perhaps still a hope for an RAF production version) reflected the then in vogue designation system whereby a naval version of an RAF production aircraft was commenced at 20, ie the Sea Venom FAW.20 being the FAA version of the RAF Venom NF.2.

The whole naval D.H.110 programme had now been transferred to Christchurch, Dorset, where W.A.Tamblin, the DH chief designer for that site, became responsible for detail changes to the new prototype and production aircraft. It was from there that the new prototype, XF828 designated the Mk.20X, made its first flight on 20 June 1955 at the hands of Jock Elliot and John Allen.
The aircraft itself still looked pretty much the same as before, however it was now becoming an integrated weapons system and a far more complex beast, especially in regard of hydraulic control systems. The added powered nose wheel steering and ‘Maxeret’ braking, were novel features at the time, it also had provision for cannon fitment (as did the previous aircraft), all production Sea Vixens retained the gun mounting structure. The British GEC AI.18 radar was chosen for production aircraft, and the dark, cramped, operators compartment required by its dim and twin screen display would become an issue for service observers.
The aircraft was powered by the service representative 11,230 Ib Avon RA28s, and introduced for the first time the distinctive ‘V’ windscreen layout, this replacing the completely frameless moulded affair of the first two aircraft.
It performed the first carrier arrested landings and catapault take-offs of the type from HMS Ark Royal in April 1956, at the hands of Cdr S.G.Orr of the Naval Test Sqn, A&AEE, based at Boscombe Down. At the same time he was also performing the same task with the Supermarine N.113, which of course went on to serve alongside the Sea Vixen as the Scimitar. XF828 also went on to test fire de Havilland Blue Jay (later Firestreak) guided missiles and conduct inflight refuelling trials.

Both remaining DH.110s would go on to serve as valuable naval research aircraft, WG240 made its last of 440 flights when it landed at Christchurch in May 1957, it ended up at Arbroath and Manadon with the RN Maintenance Schools before being broken up in 1965. XF828 made its last and 575th flight on 14th October 1959 when it arrived at RAE Bedford, before it was transferred to the School of Aircraft Handling at RNAS Culdrose, and finally perishing on the fire ground there by 1978.
Aside from John Derry and John Cunningham, Ron Clear, John Wilson, Chris Capper, Wg Cdr P.Barlow and Mr R. Horsley were all regular pilots of the D.H.110.

Sea Vixen For Service

Meanwhile procurement of the DH.110 Mk.20 proper had taken place to spec 139.P in early 1955. Rather than ordering prototypes it was felt that there would be much less delays to the programme if the first nine aircraft (XJ474-‘482) served as pre-production examples, each one testing a different facet of the designs’ functions, for example ‘476 tested radar and weapons. The Ferranti integrated weapons, instrumentation, and sighting systems, and guided missile armament, the guns/cannons being entirely deleted, were firsts for a British combat aircraft.

Indeed XJ474, the first Sea Vixen, was infact the first fully fully navalised aircraft in the 110 series (complete with hydraulic folding wings and radome), it made its first flight from Christchurch on 20th March 1957, the aircraft officially became the Sea Vixen FAW.1 in the same month.

The history of the Sea Vixen in Royal Navy service is well known, it entered front-line service in July 1959, trialling with 700Y flight and serving with 766, 890, 892, 893, and 899 Squadrons until January 1972. RNAS Yeovilton was the sole land base and became synonymous with the Sea Vixen, while the type served on HMS Centaur, Ark Royal, Victorious, and Eagle. It was operated in two main versions the FAW.1 and latter the FAW.2 which featured boom extensions with increased fuel capacity, and the more capable Red Top missile, replacing the original Firestreaks, while the internal retractable rocket weapon packs were deleted, and production of aircraft latter moved from Christchurch to Chester.

Some aircraft went on to work with FRADU, Flight Refuelling Ltd at Tarrant Rushton, and some of the research establishments, notably at Boscombe Down and Llanbedr.
In hindsight the aircraft was brilliant achievement for a British carrier based fighter, when it first joined the FAA in 1959 it gave it, very briefly, a capability in one airframe that no other naval air arm possessed, indeed it was on a par with RAF equipment of the time. It had the weapons and control integration and it offered a variety of roles from interceptor, reconnaissance, nuclear strike, buddy tanker aircraft. It was a tough airframe with superb handling, it wasn’t supersonic in level flight, but its transonic performance and handling was excellent, and even recently this was used in its favour when XP924 provided combat training for current RAF Typhoons. The Vixen had a notable accident rate in service, it is hard to fully attribute this to the design, as it entered service in a period of rapid understanding of operating large jet aircraft off carriers, however it had overly complex fuel and electrical systems, and at first poor observer emergency egress sequencing (until introduction of command ejection), which didn’t help matters. The accident rate certainly declined in the latter years of service.
However it must also be remembered that the McDonnell Douglas F-4 Phantom had already flown in early 1958 (only a year after XJ474) and was about to enter US service in late 1960. This was a far superior aircraft, in performance, crew layout, role diversity, and more, it truly elevated expectations of what carrier based combat aircraft could achieve.

In hindsight it is easy to be harsh about the Vixens timing into service, but it was a victim of indecision, having been cancelled entirely by the RN in the late 1940s, the RAF in the early 1950s before finally being taken up by the Navy again in the mid 1950s. The problems that de Havilland were having in that dangerous and fast moving period certainly didn’t help either, they were witnessing awful tragedies befall some of their high speed designs, namely with the 108 and Comet, the D.H.110 wasn’t imune from this with structural weakness in the outboard wing structures, and the poor crew layout counting against it in RAF service. In theory the Sea Vixen should have been ready for service in 1953, but even if it had it wouldn’t have been the complex integrated weapon and radar interceptor that it had become by 1959, which in itself provided the RN with a tremendous stepping stone to the next generation of aircraft.

Thankfully Sea Vixen XP924 still serves as a flying reminder of this great British aircraft.

Below, Sea Vixen FAW.2 in action (unkown source)