You might assume that distinction belongs to the de Havilland Comet airliner, which completed its inaugural flight in 1949. However, that assumption would be incorrect.

According to historical records, the honor of the first international flight by a jet airliner goes to a rather unconventional candidate: the Lancastrian. In November 1946, a Lancastrian embarked on a journey from London’s Heathrow Airport to the Aéroport de Paris at Le Bourget, marking a significant milestone in aviation history.

The Lancastrian itself was a peculiar amalgamation of aircraft components, being a lightly modified iteration of the Lancaster bomber. Functioning both as an airliner and a testing platform for various early British turbojets, the aircraft that undertook the journey to Le Bourget in 1946 was equipped with two Rolls-Royce Merlin piston engines alongside two Rolls-Royce Nene turbojets.

During the flight, the Merlin engines were rendered inactive, thus distinguishing this event as the first officially recognized international jet passenger flight. It’s worth noting, however, that only two passengers were aboard the Lancastrian for this groundbreaking voyage.

This narrative sheds light on the often-overlooked tale of the Avro Lancastrian and its pivotal role in advancing British turbojet technology, ultimately contributing to the emergence of the first generation of true jet airliners.

Origin

During the tumultuous era of World War Two, Britain found itself lacking in the production of transport aircraft. The antiquated biplane, the Vickers Type 264 Valentia, which had been in service since 1934, possessed a sluggish pace, boasting a mere top speed of approximately 130mph. Despite its shortcomings, the Valentia endured in utility until 1944.

In contrast, the introduction of the monoplane Bristol Bombay in 1939 represented a modest improvement. Functioning as both a light bomber and a transport aircraft, it could ferry a meager contingent of 24 troops at velocities reaching up to 190mph.

As the specter of war loomed closer, the British aviation sector found itself wholly engrossed in the production and advancement of fighters and bombers. Consequently, rather than diverting resources to develop indigenous transport aircraft, Britain leveraged the Lend-Lease agreement, acquiring over 2,000 units of the American Douglas C-47 Skytrain—a robust transport craft derived from the DC-3 airliner, christened the Dakota in British service. Later in the conflict, Britain received an additional 24 units of the superior Douglas C-54 Skymaster, hewn from the DC-4 airliner.

The influx of these American transport aircraft obviated the need for Britain to expend its limited manpower and resources on crafting its own contemporary transport fleet.

This symbiotic arrangement between Britain and America appears to have arisen organically, borne out of pragmatic necessity during a period when the British aviation industry was exclusively fixated on the development and mass production of fighter and bomber aircraft. However, its aftermath yielded unfortunate consequences post-war.

The extensive experience garnered by the American aviation industry in manufacturing large quantities of transport aircraft positioned it favorably to embark on the design and construction of post-war airliners. Meanwhile, Britain found itself bereft of modern indigenous transport aircraft adaptable for swift conversion into civilian airliners. As a provisional measure, British aviation firms began contemplating the repurposing of existing bombers into commercial passenger planes.

Development of Avro Lancastrian

In 1943, Canada witnessed the pioneering transformation of a Lancaster bomber into an airliner by Victory Aircraft, later amalgamated into Avro Canada. This endeavor birthed the Lancaster XPP (Lancaster Type X – Passenger Plane), a transport and passenger aircraft crafted from Lancaster Mk X bombers.

The metamorphosis entailed stripping away all turrets, fashioning a sleek new nose and tail cone, and installing two 400-gallon fuel tanks within the bomb bay. Nine XPPs emerged from this conversion, finding service with Trans-Canada Airlines (TCA) on the Montreal-Prestwick route, ferrying up to ten passengers per journey.

Across the pond, contemplation of a comparable transformation took root in Britain in early 1945 amidst the throes of war. As hostilities ebbed, cancellations of Lancaster bomber orders left Avro with a surplus of partially constructed aircraft.

Rather than consign them to the scrap heap, a decision was made to repurpose these assets into airliners, christened the Avro 691 Lancastrian. It bore striking resemblance to the Lancaster XPP, boasting faired-over turret apertures and a streamlined nose and tail.

Ample fuel tanks occupied the former bomb bay, furnishing the Lancastrian with extended range and commendable performance, clocking a cruising speed of 240mph and a range surpassing 4,000 miles. However, the Lancaster’s slender fuselage, retained in the Lancastrian, constrained its passenger-carrying capacity.

Initially designed for a crew of seven, the Lancastrian accommodated a mere nine passenger seats, relegating it to roles like VIP transport or mail delivery, curtailing its potential as a commercial airliner. Nevertheless, the British Overseas Airways Corporation (BOAC) took possession of 30 Lancastrians from April 1945 onwards, deploying them on various international routes, including those traversing England-Australia.

With scant alternatives at hand, additional British carriers also enlisted the Lancastrian. Notably, in 1946, a Lancastrian operated by British South American Airways (BSAA) embarked on the inaugural scheduled passenger departure from London’s burgeoning Heathrow Airport.

Turbojet Test Bed

The Lancastrian’s constrained passenger capacity relegated it to a transitory role within British airlines. However, its narrative took an unforeseen turn as it assumed the mantle of a test platform for turbojet engines.

Emerging as the third creation of Rolls-Royce, the RB.41 Nene turbojet boasted remarkable potency upon its inaugural operation in October 1944, propelling nearly 5,000 pounds of thrust, positioning itself amongst the globe’s most formidable engines of its time.

The inaugural flight trials of the Nene transpired within the confines of a modified American Lockheed P-80 Shooting Star, stationed at RAF Syerston in Nottinghamshire. Nevertheless, the diminutive stature of the P-80 posed logistical challenges; it lacked the capacity to accommodate the requisite instrumentation for comprehensive engine monitoring, coupled with the absence of contingency measures in the event of engine failure. The fatal outcome of a strenuous landing in December 1945 underscored the imperative for a more robust test platform.

Consequently, attention pivoted towards a larger, multi-engine aircraft. In October 1945, the maiden Lancastrian graced the Rolls-Royce Flight Test Establishment in Nottinghamshire, serving as the canvas for the integration of two Nene turbojets. This transformative process entailed the removal of the outboard Merlins, supplanted by turbojets ensconced in sleek nacelles beneath the wings. Structural modifications, including the truncation of flaps and ailerons to evade jet efflux, alongside the fortification of wing undersides with steel plates to withstand engine heat, ensued.

In August 1946, this reimagined Lancastrian took flight, propelled solely by turbojets, with the propellers of the two Merlin engines rendered inert. Eclipsing the 250 mph threshold, it affirmed its prowess as a fusion of innovation and engineering finesse.

A pivotal moment arrived in November, as this Lancastrian embarked on a voyage to Le Bourget, bearing a modest complement of two passengers: Roy Chadwick, Avro’s Chief Designer, and William Thompson of the Ministry of Supply.

Another Lancastrian was transitioned to utilize Nene engines before embarking on trials for a novel Lancastrian variant fueled by the de Havilland Ghost 50 turbojet, originally engineered for the Comet airliner.

Outfitting two Lancastrians with a duo of Ghost 50 engines in external casings, one among them was additionally equipped with the Walter HWK 109-500 liquid-fueled rocket, briefly contemplated for augmenting the Comet’s take-off with a rocket boost, albeit never integrated into the airliner’s operations.

Commencing August 1948, two more Lancastrians were repurposed as testing platforms for what would emerge as Rolls-Royce’s preeminent turbojet post-World War II, the axial flow Avon. Analogous to earlier setups, these were affixed externally to the two Merlin engines in nacelles beneath the wings.

The Avon would subsequently propel later renditions of the Comet airliner alongside British military aircraft such as the Hawker Hunter and the Vickers Valiant nuclear bomber.

The final adaptation of the Lancastrian as a turbojet test platform involved fitting it with one of the primary contenders to the Rolls-Royce Avon, the Armstrong Siddeley Sapphire. This sophisticated axial-flow turbojet engine would find application in the Gloster Javelin interceptor and initial prototypes of the Handley Page Victor strategic bomber.

In January 1950, the maiden flight of the Sapphire Lancastrian occurred. The Lancastrian proved exceptionally adept as a secure environment for engine experimentation, leading to the conversion of a total of ten into engine test platforms, accommodating both turbojets and piston engines like the Rolls-Royce Griffon and Merlin 600. None of the turbojet-equipped Lancastrians were utilized for passenger service, yet these test aircraft remained operational until the mid-1950s.

Conclusion

The Lancastrian, while serving as an airliner, fell short of achieving notable success. Its limited capacity, accommodating only a few passengers within a cramped, chilly, and noisy cabin, rendered it incapable of competing with purpose-built aircraft offering the comfort of heated, pressurized interiors.

Nevertheless, during an era when alternatives were scarce in Britain, the Lancastrian facilitated passenger air travel. Avro manufactured over 90 Lancastrians, initially repurposing bombers and later constructing bespoke models for passenger operations. Notably, British European Airways (BEA) joined BOAC and BSAA in employing the Lancastrian, with its final retirement from passenger service occurring as late as 1960.

Undeterred by the Lancastrian’s limitations, Avro pursued the conversion of bombers into airliners. In 1944, they introduced the Lancaster IV, featuring an expanded fuselage and more robust engines, later redesignated as the Avro Lincoln and adopted by the RAF as a Lancaster replacement. Simultaneously, Avro embarked on designing a new airliner based on the Lincoln but distinct in its approach.

This endeavor culminated in the Avro Tudor airliner, boasting a pressurized circular fuselage, although retaining the bomber’s Merlin engines. Throughout the 1950s, various airlines operated Tudors, with the final iteration, the Tudor 9 (subsequently named the Avro Ashton), powered by four Rolls-Royce Nene turbojets—engines initially trialed in the Lancastrian.

Interestingly, despite its shortcomings as an airliner, the Lancastrian excelled as a test platform for turbojet designs. With ample space for instrumentation, it adeptly accommodated experimental engines. Moreover, in case of engine failure, its two Merlin engines ensured safe flight and landing, underscoring its pivotal role in furnishing crucial data and experience vital for the advancement of British turbojet technology in the 1950s.