Vickers Valiant

The Vickers-Armstrongs Valiant was a British four-jet bomber, once part of the Royal Air Force's V bomber force. 

The Valiant was originally developed for use as high-level strategic bomber. When the other V-bombers came into use it was also used as a tanker. However, when the RAF moved to low level attacks, low level flying in the Valiant caused premature fatiguing. Rather than repair or rebuild the fleet, it was grounded and the Handley Page Victor took over the tanker role. 

The Valiant was a conservative design, with a shoulder-mounted wing and four Avon RA.3 turbojets, each of 6,500 lbf (29 kN) thrust, two in each wing root. The design gave an overall impression of a plain and clean aircraft with simple aerodynamics. 

As the Valiant was an entirely new class of aircraft for the RAF, the 232 Operational Conversion Unit was established at RAF Gaydon. The first operational RAF unit to be equipped with the Valiant was 138 Squadron, also at RAF Gaydon, though it later moved to RAF Wittering. At its peak, the Valiant equipped at least seven RAF squadrons. 

The Valiant was the first of the V-bombers to see combat, during the Anglo-French-Israeli Suez intervention in October and November 1956. During Operation Musketeer, Valiants operating from the airfield at Luqa on Malta dropped conventional HE bombs on Egyptian targets. 

Valiants were originally assigned to the strategic nuclear bombing role as were the Vulcan and Victor B.1s when they became operational. By the early 1960s these aircraft were joined by the Victor B.2 and Vulcan B.2. Originally the bombing role was at high level but with the shooting down of the Lockheed U-2 flown by Gary Powers by an early SA-2 Guideline missile, the SAM threat caused the V-force to train for low-level attack. They were repainted in grey/green camouflage, replacing their anti-flash white scheme. The Valiant did not carry the Blue Steel nuclear-tipped stand-off missile that was carried by the Victor and Vulcan. 

Three squadrons of Valiants were assigned in the low-level tactical bombing role (49, 148, 207) and two more squadrons (90 and 214) served as tankers. They also continued to give service in the strategic photo-reconnaissance role (543 squadron). 

Low-level operations proved too much for the Valiant. Inspections of the entire fleet showed that the wing spars were suffering from fatigue. In early 1965 the Wilson government with Denis Healey as Secretary of State for Defence decided that the expense of repairs could not be justified and the fleet was permanently grounded.

Vickers Valiant
Class Aircraft
Type Bomber
Manufacturer Vickers Limited
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1951
Country Name Operational Year Retirement Year
United Kingdom - UK (Great Britain) 1955 1965 View
ManufacturerName Production From Production To Quantity
Vickers Limited 107 View

The Valiant was a conservative design, with a shoulder-mounted wing and four Avon RA.3 turbojets, each of 6,500 lbf (29 kN) thrust, two in each wing root. The design gave an overall impression of a plain and clean aircraft with simple aerodynamics. George Edwards described it appropriately as an "unfunny" aircraft. The root chord thickness ratio was 12% and allowed the Avon engines to be within the wing rather than on pods as in the contemporary Boeing B-47. This "buried engine" fit contributed to the aircraft's aerodynamic cleanliness. However, it made engine access for maintenance and repair difficult and increased the risk that the failure of one engine would contribute to the failure of its pair due to flying debris such as turbine blades. It also increased the complexity of the design of the main spar which had to be routed around the engines.

The Valiant wing had a "compound sweep" configuration, devised (and patented) by Vickers aerodynamicist Elfyn Richards. It had a 37° angle of sweepback in the inner third of the wing, reducing to an angle of about 21° at the tips. This was because the thickness/chord ratio could be reduced closer to the tips, balancing this against the sweep reduction in postponement of Mach effects such as buffeting and drag rise. Limiting in-service speed was Mach 0.84 and a typical cruise of Mach 0.75 at heights up to 55,000 ft when light. A "clean" Valiant (one without underwing tanks) could climb straight to 50,000 ft after takeoff unless it had heavy stores in the large bomb bay. The tail surfaces were swept back, and the horizontal tailplane was mounted well up the vertical fin to keep it clear of the engines' exhaust. The wing loading was low by modern standards and the Valiant was fitted with double-slotted flaps for takeoff (20° flap) and landing (40° or full flap, about 60°). The aircraft featured tricycle landing gear, with twin-wheel nosegear and tandem-wheel main gear retracting outward into the wing. Most of the aircraft's systems were electric including flaps and undercarriage.

Initial Valiant production aircraft had four Rolls-Royce Avon 201 turbojet engines, with 9,500 lbf (42 kN) thrust each. Trials were performed with two underwing de Havilland Sprite rocket booster engines; however these were deemed unnecessary due to the availability of more powerful Avon variants, as well as fear of accidents if one booster rocket failed on take-off, resulting in asymmetric thrust. The engine inlets were long rectangular slots in the first prototype, but later Valiants featured oval or "spectacle" shaped inlets to permit greater airflow for more powerful Avon engine variants. The jet exhausts emerged from fairings above the trailing edge of the wings. Water injection was fitted to some Valiants and increased takeoff thrust by about 1,000 lb (450 kg) per engine.

Electrics were based on 112 volt direct current generators for functions requiring large amounts of electrical power and a 28 V DC system provided a controlling voltage for other systems and the actuators that initiated the high-voltage system functions. Backup batteries were a bank of 24 V units and 96 V batteries. 115 V alternating current was provided to systems such as radio and radar that required it. The brakes and steering gear were hydraulic, however pumps were electrically driven. The flight controls consisted of two channels of power control with full manual back-up; flying in manual was allowed but limited.

The Valiant was built around a massive backbone beam that supported the wing spars and the weight of bombs in the long bomb bay. The crew were contained in a pressurized "egg" and consisted of pilot, copilot, two navigators, and an electronics operator. Only the pilot and copilot had ejection seats. The other three crew members had to bail out of the crew door on the port side of the fuselage. The main structural components, spars and beams etc. were built with the zinc/magnesium/copper aluminium alloy designated as DTD683 in the U.K., which was problematic in the production of the Valiant. The aircraft was designed with a 'Safe-Life' strategy. This combination of 'Safe-Life' and DTD683 came to be viewed as a severe mistake. In 1956, a publication within the Journal of the Institute of Metals condemned the material DTD683 as being unstable and capable of catastrophic failure while stressing the airframe close to its design limits. The "Safe-Life" design strategy was dismissed by a Lockheed engineer in a talk given to the Royal Aeronautical Society in 1956, because it did not guarantee safety in a catastrophic failure.

The Valiant B.1 could carry a single 10,000 lb (4,500 kg) nuclear weapon or up to 21 1,000 lb (450 kg) conventional bombs in its bomb bay. Large external fuel tanks under each wing with a capacity of 1,650 Imp gal (7,500 L), could be used to extend range.


Nuclear deterrent

The first squadron to be equipped with the Valiant was 138 Squadron, which formed at RAF Gaydon on 1 January 1955, with 232 Operational Conversion Unit forming at Gaydon on 21 February 1955 to convert crews onto the new bomber. Since the Valiant was part of an entirely new class of bombers for the RAF, the crews for the new type were selected from experienced aircrew, with first pilots requiring 1,750 flying hours as an aircraft captain, with at least one tour flying the Canberra, with second pilots needing 700 hours in command and the remaining three crewmembers had to be recommended for posting to the Valiant by their commanding officers. Valiants were originally assigned to the strategic nuclear bombing role, as were the Vulcan and Victor B.1s when they became operational. At its peak, the Valiant equipped nine RAF squadrons.

A Valiant B.1 (WZ366) of No 49 Squadron was the first RAF aircraft to drop a British operational atomic bomb when it performed a test drop of a down-rated Blue Danube weapon on Maralinga, South Australia, on 11 October 1956.

On 15 May 1957, a 49 Squadron Valiant B(K).1 dropped the first British hydrogen bomb, the "Short Granite" (AKA "Green Granite Small"), over the Pacific as part of Operation Grapple. The test was largely a failure, as the measured yield was less than a third of the maximum expected and while achieving the desired thermonuclear explosion the device had failed to operate as intended. The first British hydrogen bomb that detonated as planned, "Grapple X Round A" (AKA "Round C1"), was dropped on 8 November 1957. The Grapple series of tests continued into 1958, and in April 1958 the "Grapple Y" bomb exploded with 10 times the yield of the original "Short Granite". Testing was finally terminated in November 1958, when the British government decided it would perform no more air-delivered nuclear tests.

Conventional warfare

Peacetime practice involved the dropping of small practice bombs on instrumented bombing ranges, also a system of predicted bombing using radio tones to mark the position of bomb drop over non-range targets, the bomb error being calculated by a ground radar unit and passed either to the crew during flight or to a headquarters for analysis. When the Navigational and Bombing System (NBS) was fitted and crews well-trained, bombing accuracies became typical of other aircraft of the time and from 40,000 ft/12,190 m a 100 yd (90 m) error was not uncommon.

The Valiant was the first of the V-bombers to see combat, during the Anglo-French-Israeli Suez intervention in October and November 1956. During Operation Musketeer, Valiants operating from the airfield at Luqa on Malta dropped conventional HE bombs on targets inside Egypt. Although the Egyptians did not oppose the attacks and there were no Valiant combat losses, the results of the raids were disappointing. Their primary targets were seven Egyptian airfields. Although the Valiants dropped a total of 842 tons (856 tonnes) of bombs, only three of the seven airfields were seriously damaged. It was the last time the V-bombers flew a war mission until Avro Vulcans bombed Port Stanley airfield in the Falkland Islands during the Falklands War in 1982.

Tanker operations

Valiant tankers were flown by 214 Squadron at RAF Marham, operational in 1958 and 90 Squadron at Honington, operational in 1959. These aircraft were fitted with a Hose Drum Unit (HDU or "Hoodoo") in the bomb bay. The HDU was mounted on bomb-mounting points and could be removed if necessary. However, this arrangement meant that the bomb doors had to be opened in order to give fuel to a receiver aircraft.

With inflight refuelling probes fitted to Valiants, Vulcans and Victors and Valiant tankers available, the so-called "Medium Bomber Force" of the RAF could go beyond "medium range", and the RAF had a true strategic bombing capability. Long-range demonstration flights were made using Valiant tankers pre-deployed along the route. In 1960, a Valiant bomber flew non-stop from Marham in the UK to Singapore and in 1961 a Vulcan non-stop from the UK to Australia. The two tanker squadrons regularly practised long range missions, refuelled by other Valiant tankers on the way. In 1963 a squadron of Gloster Javelin All-weather interceptors was refuelled in stages from the UK to India (Exercise "Shiksha"). The tankers going on to Butterworth near Penang in Malaysia and returning the Javelins to the UK three weeks later. Four of the Javelins were refuelled to Singapore to join 60Sqn during Confrontation. Other aircraft refuelled at this time included Victor and Vulcan bombers and English Electric Lightning fighters, also the de Havilland Sea Vixen fighter of the Royal Navy.

Countermeasures and reconnaissance roles

Valiants of No. 18 Squadron RAF at RAF Finningley were modified to the "radio countermeasures" (RCM) role - RCM is now called "electronic countermeasures" (ECM). These aircraft were ultimately fitted with APT-16A and ALT-7 jamming transmitters, Airborne Cigar and Carpet jammers, APR-4 and APR-9 "sniffing" receivers, and chaff dispensers. At least seven Valiants were configured to the RCM role.

Valiants of number 543 Squadron at RAF Wyton were modified to serve in the photographic reconnaissance role.

Fatigue failures and retirement

Originally the bombing role was at high level but with the shooting down in 1960 of the Lockheed U-2 flown by Gary Powers by an early SA-2 Guideline missile, the SAM threat caused the V-force to train for low-level attack. They were repainted in grey/green camouflage, replacing their anti-flash white scheme. Three squadrons of Valiants were assigned to the low-level tactical bombing role (49, 148, 207) and two more squadrons (90 and 214) served as tankers. They also continued to serve in the strategic photo-reconnaissance role (543 Squadron).

In 1956, Vickers began a series of low level tests in WZ383 to assess the type for low level flight at high speed. Several modifications to the aircraft were made, including a metal radome, debris guards on the two inboard engines, after six flights the aileron and elevator artificial feel was reduced by 50%. Pilots reported problems with cabin heating and condensation that would need remedying. The aircraft was fitted with data recording equipment and this data was used by Vickers to estimate the remaining safe life of the type under these flying conditions. Initially a safe life of 75 hours was recommended, which became "the real figure might be less than 200 hours". How many hours a Valiant flew in a year was seen as an operational issue for the RAF, Vickers could only give recommendations.

Later the RAE ran a similar series of tests that more closely resembled actual operational conditions including low level and taxiing, the report published in 1958 produced data that could be used to get a better grasp on which flight conditions produced the most damage, and better enable a projection of the future life span for the type.

In May 1957 Flight reported an "incident at Boscombe Down, when a Valiant cracked a rear spar member after a rocket-assisted take-off in overload conditions" This aircraft was the second prototype WB 215, it was subsequently broken up for wing fatigue testing, it had flown 489 hours.

By the time the type was scrapped only around 50 aircraft were still in service, the rest had been slowly accumulating at various RAF Maintenance Units designated as "Non effective Aircraft"

In July 1964 a cracked spar was found in one of the three Valiants (either WZ394 - Wynne, or WZ389 - Morgan) involved in Operation Pontifex followed shortly afterward on 6 August, by a failure of a rear spar at 30,000 ft, in WP217 an OCU aircraft from Gaydon flown by Flight Lieutenant "Taffy" Foreman. The aircraft landed back at Gaydon but without a flap because of damage in the rear of one wing. Later inspection of the aircraft showed the fuselage skin below the starboard inner plane had buckled, popping the rivets; the engine door had cracked and the rivets had been pulled and the skin buckled on the top surface of the mainplane between the two engines. Both these aircraft were PR variants, operating at 30,000 ft.

Denis Healey said when asked to make a statement about the scrapping in the House of Commons, that it "was not in any way connected with low-level flying". Barry Jones commented in his book “A question has to be asked. For two years before the demise of the Valiant, Handley Page at Radlett had 100 Hastings go through their shops. They were completely dismantled and rebuilt, having DTD683 components removed and replaced by new alloy sections. What was so special about the Hastings and why was the Valiant not treated similarly? Perhaps we will know one day -- but I doubt it.” In a Flight report about the scrapping it states "Fatigue affected all Valiants ... not only those ... used for ... low flying" it was the "limited-life" design (Safe-Life) or "actual fatigue problems" (DTD683) that were the cause.

Inspections of the entire fleet showed that the wing spars were suffering from fatigue at between 35% and 75% of the assessed safe fatigue life, probably due to low level turbulence. After this inspection, the aircraft were divided into three categories, Cat A aircraft continuing to fly, Cat B to fly to a repair base, and Cat C requiring repair before flying again. The tanker squadrons had the highest proportion of Cat A aircraft because their role had been mainly at high level. This also caused the methods of assessing fatigue lives to be reviewed. However, in January 1965, the Wilson government with Denis Healey as Secretary of State for Defence decided that the expense of the repairs could not be justified and the fleet was permanently grounded as of 26 January 1965. The QRA alert that had been in place for SACEUR was maintained until the final grounding and was then allowed to lapse.

On 9 December 1964, the last Valiant tanker sortie involved refuelling Lightning aircraft over the North Sea. On the same day, the last Valiant bomber sortie was carried out, using XD818. The Valiant was Vickers' last purpose-built military aircraft. It was followed by the Vanguard, a passenger turboprop designed in 1959, and the Vickers VC10, a jet passenger aircraft from 1962, also used as a military transport and tanker by the RAF.

Role Strategic bomber, Aerial tanker
Manufacturer Vickers-Armstrongs
Designer George Edwards
First flight 18 May 1951
Introduction 1955
Retired January 1965
Primary user Royal Air Force
Number built 107


General characteristics

  • Crew: five - two pilots, two navigators, electronics engineer
  • Length: 108 ft 3 in (32.99m)
  • Wingspan: 114 ft 4 in (34.85m)
  • Height: 32 ft 2 in (9.80m)
  • Wing area: 2,362 ft (219m)
  • Empty weight: 75,880 lb (34420 kg)
  • Military load: 21,000 lb (9500kg)
  • Max takeoff weight: 138,000 lb (62600kg)
  • Overload take-off: 175,000 lb (79400kg) with underwing tanks
  • Powerplant: 4 x Rolls-Royce Avon RA28 Mk 204 turbojet, 10,000 lb (44kN) each

Performance

  • Maximum speed: Mach 0.84 at 30,000 ft plus, 414 mph (666km/h)
  • Range: 4,500 miles with 10,000 lb bomb halfway, with underwing tanks (7200km)
  • Service ceiling 54,000 ft (21,000 m)
  • Rate of climb: 4,000 ft/min (20m/s)
  • Wing loading: 58 lb/ft (286kg/m)
  • Thrust/weight: 0.29

Armament

  • 1x10,000 lb (4500 kg) bomb or
  • 21x1,000 lb (450 kg) bombs

End notes