STATUS: Retired, Out-of-Service
MANUFACTURER(S): Saunders-Roe (SARO) - UK
OPERATORS: Canada; United Kingdom
LENGTH: 56.79 feet (17.31 meters)
WIDTH: 79.99 feet (24.38 meters)
HEIGHT: 18.73 feet (5.71 meters)
WEIGHT (EMPTY): 11,100 pounds (5,035 kilograms)
WEIGHT (MTOW): 22,000 pounds (9,979 kilograms)
ENGINE: 2 x Bristol Pegasus X 9-cylinder air-cooled radial engines developing 920 horsepower each.
SPEED (MAX): 142 miles-per-hour (228 kilometers-per-hour; 123 knots)
RANGE: 1,740 miles (2,800 kilometers; 1,512 nautical miles)
CEILING: 19,898 feet (6,065 meters; 3.77 miles)
RATE-OF-CLIMB: 1,180 meters (360 meters-per-minute)
Detailing the development and operational history of the Saunders-Roe A.27 London Reconnaissance Flying Boat Aircraft.
Entry last updated on 2/20/2018.
Authored by Staff Writer. Content ©www.MilitaryFactory.com.
The SARO London borrowed much from the British flying boat designs peppering the 1920s and, in many ways, her retirement was something of an end to the era - aviation's "golden age" if you will. Pressed into wartime service during World War 2, the London served for only a limited time in equally limited numbers while charged with keeping an eye on the waters off England and over the Mediterranean Sea. Like so many other outclassed aircraft appearing in the middle 1930s and called to fight, the Saro London would go down in aviation history as one of the many unsung heroes doing their part in the early years of the war.
Origins of the London lay in a pre-war British Air Ministry Specification - designated R24/31 - which called for a multi-role flying boat. The firm of Saunders-Roe ("SARO") delivered a design based on their previous failed Saunders A.7 "Severn" attempt, a three-engine flying boat designed for maritime patrol duties of which only one was ever built. The new design was designated as the A.27 London and saw a first prototype completed and flown sometime in 1934. The aircraft was fitted with a pair of Bristol Pegasus II radial piston engines mounted on an uneven-span (sesquiplane) biplane wing assembly. This single prototype actively operated until 1936 to which production forms officially appeared from the assembly lines in March. The initial production models were designated as London Mk.I, the major difference being their use of Bristol Pegasus III-series 820 horsepower radial piston engines.
Ten such examples were produced before the introduction of the Bristol Pegasus X engines of 915 horsepower forced the new designation of London "Mk.II" to be used. All of the early-production Mk.I models were brought up to the new Mk.II standard and redesignated to the new mark in the process. Some twenty Mk.II aircraft were ultimately built. In all, a total of thirty London Saros were constructed and delivered (not including the single prototype).
The Saro London was crewed by a complement of six personnel. She held a wingspan of 80 feet with a running length of over 56 feet. Her height measured in at nearly 19 feet. Total win area was 1,425 square feet. When empty, the London weighed in at 11,100lbs and roughly 18,400 loaded. Her maximum take-off weight (MTOW) was reported to be around 22,000lbs. Maximum speed was 155 miles per hour while cruise speed was listed at 128 miles per hour. Range topped out around 1,100 miles and her service ceiling was limited to just under 20,000 feet. She maintained a rate of climb equal to 1,180 feet per minute.
External design of the SARO London was typical of mid-sized flying boats of the time. Most distinct of this class of aircraft was the boat-shaped hull running from the nose of the airframe to the base of the empennage (tail section). It was this design element that allowed the London the capability to slice through water for landings and take-off but, at the same time, limited such activity to the water - that is, the London retained no undercarriage for operating from land bases. While her lower half maintained the appearance of an ocean-going vessel, her upper half was all aircraft. She sported a slightly curved nose section with slab and noticeably ribbed siding. The cockpit was set just aft of the nose assembly and elevated from the airframe to provide for good all-around views through a framed glass housing. Entry was via a rectangular hatch along the starboard fuselage side just below and aft of the flightdeck. The slab-sided fuselage tapered into a large "Tee" style tail assembly, made up of two large vertical tail fins set upon a horizontal plane. The biplane wing arrangement consisted of a lower span, which was shoulder-mounted onto the fuselage, and the upper span held in place by large angled struts. Each lower wing assembly held a single underslung float to help control the aircraft's sway when on the water. The wings ran through the two high-mounted engine nacelles housing the powerplants. The powerplants were raised a distance away from the airframe and fitted above and behind the flightdeck in an effort to keep the engines free of the corrosive effects of water spray during take-off and landing activities. Fuselage construction was of all-metal while the wings were covered over in fabric.
As a reconnaissance platform, flying boats like the SARO London were prime targets for patrolling enemy fighters. Though this class of aircraft maintained a healthy operational range from which to operate in, she made for a large, slow moving target. As such, she was fitted with up to three Lewis-brand 7.7mm machine guns for defensive purposes. One was positioned forward at the bow while another was positioned aft, both emplacements were open-air with the guns on ring-mounts. The third machine gun was situated amidships. Her offensive prowess when combating surface ships was limited to 2,000lb of ordnance - this in the form of either depth charges, conventional drop bombs or mines - mounted near the wing roots of the lower span. An optional dorsal fuel tank could be installed to help improve operational range (many existing SARO London photographs feature this elongated tank structure just aft of the cockpit).
Operators ultimately included the Royal Canadian Air Force and No. 201, No. 202, No. 204, No. 209, No. 210, No. 228 and No. 240 squadrons of the Royal Air Force. Beyond these users, the London was never in service with another nation in her tenure let alone exported to customers.
At the beginning of World War 2, Londons were pressed into action with RAF Coastal Command, eventually seeing action over the North Sea and across the Mediterranean Sea. They served well in running active reconnaissance patrols as called upon and were ready to engage surface ships if needed. Despite her seemingly archaic appearance, there were many biplanes utilized in these early years of World War 2 that served valiantly when the need called for it. They preserved the status quo of the war until newer and better systems could be made ready and available. The tour of the London began to end sometime in 1940 while the last active group operated around Gibraltar until June of 1942.
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Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.
Relative Maximum Speed Rating
This entry's maximum listed speed (142mph).
Graph average of 112.5 miles-per-hour.
Graph showcases the Saunders-Roe London Mk.II (A.27)'s operational range (on internal fuel) when compared to distances between major cities.
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
* Commercial Market High belongs to Cessna 172.
** Military Market High belongs to Ilyushin Il-2.