The Avro Lincoln was a British heavy bomber developed during World War Two as a successor to the Avro Lancaster. Although produced too late for it to have any wartime effect, the Lincoln had a successful postwar career with the British, Australian, and Argentine Air Forces where it was adapted to carry out a surprising array of functions.
However, like many other aircraft assembled at the time, the piston-powered Lincoln was ultimately phased out because of the introduction of far superior jet engine technology.
- The Lincoln
- Flight Trials and Production
- Australian and Argentinian Air Forces
In 1942 the UK Air Staff’s Defence Committee officially announced that the Avro Lancaster Bomber was going to be replaced by the Avro Lancaster after concluding that it was “the best that could be brought into service in time to effect the future course of the war.”
With the installation of four Rolls-Royce Merlin RM.14.SM engines, the Lancaster was estimated to have a weight of 70,000 pounds, a service ceiling of 34,000 feet, and a top speed of 346 miles per hour at 20,000 feet or 225 miles per hour at 30,000 feet.
Once the developmental cycle had been completed, the Lincoln was to mainly serve in the Pacific Theatre where a planned British Pacific Tiger Force was to give the Americans a helping hand in defeating Imperial Japan.
In July 1943 a prototype contract was issued followed by an order for 162 production units a month later. Interestingly, the Avro Lincoln was essentially the same as the Mark III version of the Lancaster apart from a few changes – it was to have better weapons, superior protection, and either Merlin 85 or 68 engines.
Since the new bomber was similar to its predecessor, Bomber Command wanted to keep the moniker ‘Lancaster’ despite objections from the manufacturer, Avro, who offered Lincoln, Sandringham, or Stafford as suggestions.
It did not take much to persuade Bomber Command to change the name, for in June 1944 J.D. Breakey, Assistant Chief of the Air Staff, commented how ‘Lincoln’ was “very appropriate as it falls within the bomber category and is moreover the name of a city within the area in which Bomber Command operates their aircraft.” Accordingly, by August the Avro 694 Lancaster IV and V would become the Lincoln B.Mk.I and Lincoln B.Mk.II.
With an empty weight of 43,000 pounds and a maximum take-off weight of 75,000 feet, the Avro Lincoln was 23.86 meters in length, 5.27 meters in height and had space for a crew of 7 consisting of a front gunner, pilot, flight engineer, navigator, wireless operator, and a dorsal and rear gunner.
The Lincoln was propelled by four Rolls-Royce Merlin 85 in-line piston engines that gave it a top speed of 295 miles per hour, a range of 1470 miles, and an altitude ceiling of 30,500 feet which it could climb at 800 feet per minute.
The Merlins were enclosed in cylindrical cowlings and powered either Rotol or de Havilland four-blade constant-speed full-feathering propellors that were 13 feet in diameter. They were fed by six fuel tanks situated between inboard nacelles, in the fuselage, and in each intermediate wing panel, which had a maximum volume of 3,580 gallons.
The Avro Lincoln had an all-metal semi-monocoque fuselage divided into five main sections comprising the nose with a front turret, the cabin, the centre section, the aft section bearing the dorsal turret, and the tail segment with a rear turret.
The Lincoln possessed a modified nose fitted with twin 12.7 mm machine guns that had previously been tested out on a Lancaster in an attempt to improve the bombardier’s prone position. As such, when it was successfully evaluated in July and August of 1943, it was decided that the same arrangement would make its way onto the Avro Lincoln.
Moreover, dual 12.7 mm machine guns were also fitted in tail and dorsal turrets, while up to 14,000 pounds of bombs could be loaded.
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The wings, which were 36.58 meters in span and 132.2 square meters in area, were structured with two spars and heavy ribbing and composed of stressed light alloy skin. The Lincoln was manoeuvred via metal ailerons that allowed for wing flexing as well as hydraulically operated trailing edge split flaps. Navigation was facilitated by a H2S radar located in the ventral fuselage, an F-24 camera, and other equipment such as a Rebecca Mark II Loran and a Gee Mark II.
The Lincoln’s all-metal cantilever tail unit was ripped directly from the Lancaster and was later modified to have a larger rudder area. Attached to it were twin elliptical fins and rudders with sheet metal covering all surfaces. Below, the Lincoln featured an undercarriage that had two retractable main wheels and a single non-retractable tail wheel.
Flight Trials and Production
The Lincoln PW925 prototype made its maiden voyage on June 9th 1944 from Ringway, near Manchester, with Captain H.A. Brown at the helm. Next, it went through the preliminary assessment and brief performance trials at Boscombe Down between July 15th and July 23rd, where it was found to have pleasant handling characteristics.
In August 1945 the Lincoln underwent RAF operational trials, while later that year it would go through winter trials in Canada and tropical assessments at Khartoum.
With the Avro Lincoln now fully fleshed out full-scale production commenced in 1945, with the first units rolled out in February. The original plan was to cut Lancaster production from 284 a month in November 1944 to 124 a month in June 1945, with a gradual phasing out by November. In its place, Lincoln production would rise from 66 a month in March 1945, 123 a month in May, and finally 200 a month in August.
However, the dropping of the atomic bomb on Nagasaki and Hiroshima in August 1945 would mean these targets were never reached. In addition to the disbanding of the British Pacific Tiger Force on October 31st 1945, many production versions of the Lincoln would also be cancelled.
Nevertheless in the postwar years, many would serve in the RAF and abroad in a variety of capacities. The first RAF mission to involve Avro Lincolns occurred in March 1946 when No.44 Squadron was tasked with dumping surplus wartime incendiary bombs in Cardigan Bay. Later in November as part of a training routine, another squadron of Lincolns completed a 20,000-mile round trip from Scampton to Santiago, Chile.
Over the next few years, RAF Lincolns would embark on a whistle-stop demonstration tour to many countries, despite its piston engine being considered outdated with the advent of jet engines.
In July and August 1947 No. 617 Squadron toured around the United States, with similar trips conducted in Rhodesia, Singapore, as well as Pakistan, where in July 1949 as part of a 12-day tour live bombing demonstrations were undertaken.
In March 1950 the Lincoln would see real combat in Malaya, where they were tasked with bombing Communist strongholds. In February and March 1951 Lincolns alone would be responsible for unleashing over one thousand 500-pound bombs during Operation Jackpot, which targeted terrorists occupying the Selangor/Negri Sembilan frontier.
Equally in 1953, Lincolns were deployed to Kenya where they were used to crush Mau Mau insurgents who had overrun parts of the country. Augmented with tropical sand filters on the engine intakes, from their Nairobi base the Lincolns dropped explosives on jungle hideouts and other targets until operations concluded in July 1955.
As part of the Royal Air Force, 52 Lincolns would also participate in the annual home defence practice, Exercise Pinnacle, held between September 29th and October 9th 1951, which included mock raids on Bristol and Birmingham.
On the other hand, the weaknesses of the Lincoln’s piston engine became apparent when they were intercepted 72 times off the coast while closing in on their target. In fact, by May 1952 only Hemswell, Upwood, Waddington, and Wyton accommodated Lincoln squadrons since many had been replaced with jet-powered equivalents such as the American B-29 Washington.
But although Lincolns were out of favour they were still utilized on routine missions. On one such occasion on March 12th 1953, a Lincoln flew towards Berlin in a flight aimed at maintaining UK flying rights within Berlin corridors.
However, during its passage the Lincoln strafed too close to the Russian zone and was shot down by MiG-15 jet fighters, becoming the only RAF Lincoln to ever be shot down in the process.
Australian and Argentinian Air Forces
In March 1946 the Australian government ordered 61 Lincolns to serve as part of the Royal Australian Air Force (RAAF), with many re-engined with Merlin 102 engines which improved overall performance by 10%. While the Australian No.1 Squadron conducted sorties over Malaya until July 1958 in combination with the RAF, the No.2 and No.6 Squadrons were principally utilized for home defence.
It was in the Land Down Under that the Avro Lincoln Mark 31, used for reconnaissance, search and rescue, and anti-submarine purposes, was also developed, with the initial batch of units converted and delivered by December 1953.
These modified Lincolns served for around 8 years, with the last flight taking place on June 14th 1961 when it was flown to Darwin for fire-fighting practice.
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Lincolns also had a considerable presence in the Argentinian Air Force after Argentine officials were impressed by their performance during a demonstration at RAF Binbrook in 1947. As a result, between September 1947 and February 1948 30 Lincolns with their HS2 radars and navigation equipment removed, were delivered to the South American nation mainly to act as the strategic bombing arm of their fleet.
But the Lincolns were also employed for other means, such as in 1953 when one unit equipped with a camera in the crew access hatch assisted the Military Geographical Institute by photographing various regions of Argentina. Furthermore, two Lincolns were adapted for use as long-range transports for Argentina’s Antarctic Research teams, serving until July 1966.
- Crew: 7 or 8 (pilot, flight engineer/co-pilot, navigator, wireless operator, front gunner/bomb aimer, dorsal and rear gunners)
- Length: 78 ft 3.5 in (23.863 m)
- Wingspan: 120 ft (37 m)
- Height: 17 ft 3.5 in (5.271 m)
- Empty weight: 44,188 lb (20,043 kg) equipped
- Max takeoff weight: 82,000 lb (37,195 kg)
- Powerplant: 4 × Rolls-Royce Merlin 85 or Packard-Merlin 68 V-12 liquid-cooled piston engines, 1,750 hp (1,300 kW) each
- Maximum speed: 310 mph (500 km/h, 270 kn) at 18,300 ft (5,600 m)
- Cruise speed: 215 mph (346 km/h, 187 kn) at 20,000 ft (6,100 m)
- Range: 2,800 mi (4,500 km, 2,400 nmi) at 15,000 ft (4,600 m) with 14,000 lb (6,400 kg) bomb load at 200 mph (170 kn; 320 km/h).
- Service ceiling: 30,500 ft (9,300 m)
- Rate of climb: 800 ft/min (4.1 m/s)