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Saunders-Roe A.36 Lerwick Reconnaissance Flying Boat

Design flaws limited SARO Lerwick production to just 21 airframes - and ten of these were lost to accidents.

 Updated: 5/1/2015; Authored By Staff Writer; Content ¬©

Along with the Short Brothers and Supermarine, Saunders-Roe (SARO) was a principle flying boat developer for the United Kingdom in the prewar and World War 2 years. The SARO "Lerwick" (Model A.36) was perhaps one of its more forgettable designs in that design flaws and tricky handling severely hampered its service record, leading to just twenty-one of the aircraft being delivered. Its accident rate proved so high that the type was retired as soon as 1942 though the series was only in service since mid-1939. First flight of a prototype was in November of 1938 and operators were limited to the British Royal Air Force (RAF) while Canadians also trained on the type.

SARO engineers adopted the proven flying boat form with high-mounted wings and leading edge engine nacelles. The fuselage sported a boat-like hull underside for water-borne landings and the flightdeck was seated high over and aft of the nose assembly for excellent vision out-of-the-cockpit. Pontoons were affixed under each wing (outboard of the engine installations) to prevent tipping during water-running and when on choppy seas. The tail unit was traditional in its arrangement, featuring a single vertical tail fin and low-mounted horizontal planes. Its crew numbered six in all and dimensions included a length of 19.4 meters with a wingspan out to 24.6 feet and height of 6 meters. Maximum Take-Off Weight (MTOW) was listed at 33,200lbs.

Power was served through 2 x Bristol Hercules II series radial piston engines, each developing 1,375 horsepower and driving three-blade propeller units. The engines were mounted in a position where pilots held clear views of them to identify any dangers (particularly fires). Maximum speeds reached 215 miles per hour while cruising was typically done in the 165 mile per hour range. Operational ranges were out to 1,540 miles and the aircraft's service ceiling was 14,000 feet. Rate-of-climb was a pedestrian 880 feet per minute - though expected for an aircraft of this size and role.

As a military airplane, the Lerwick was outfitted for both the defensive and offensive role. Her slow speed and unenviable size dictated that a defensive-minded network of machine guns be used and this constituted a total of seven 7.7mm Vickers K series machine guns being carried. One was fitted within a turret at the nose of the aircraft with a further four in another turret mounted to the tail (at the rear base of the vertical tail fin). The remaining pair of guns were manned through a dorsal turret along the fuselage spine near midships. These installations were all intended to protect the aircraft from incoming enemy interceptors from virtually any angle - save for the vulnerable belly. For the maritime strike role, she carried up to 2,000lbs of conventional drop ordnance including depth charges. The aircraft could therefore be called upon to hit targets near the coast, engage unarmed enemy shipping, or attempt to hunt enemy submarines.

Three completed Lerwicks served as prototypes for the flight testing phase. Evaluations showcased a heavy, underpowered aircraft that could not operate on one engine and required a good deal of attention at the controls. This period of testing led to several modifications of the base design including increased wing surfaces for added control but these held a limiting effect over the course of the Lerwick's operational career. The wings eventually became a notable weak spot in the design - the fault proven in operational service through several aircraft losing their wings, particularly during or after rough water landings.

Lerwicks were delivered in the summer of 1939, just prior to Britain's formal involvement in World War 2 (to come in September). However, issues were already apparent in the short time the aircraft was in operation for the fleet was grounded as soon as October with the much more well-regarded (and aged) SARO London flying boats being used in their place for the interim. Nevertheless, short of many war-making goods, the British still pushed use of the Lerwick and production continued into 1940 and, during this period, the accident rate of the aircraft began to climb, forcing more restricted use of the type. The aircraft were, however, still used for maritime patrol and strikes though success ultimately proved elusive.

With the arrival of Consolidated PBY "Catalina" flying boats from the United States beginning in April of 1941, the Lerwick was officially withdrawn from frontline service with the RAF in May. From here, the type was used to train future flying boat aviators and crew as well as mechanics on the finer points of operating such unique aircraft. These also served to train Canadian airmen before the line was given up for good by 1943. No airframes were spared the scrapman's torch and, as such, non exist in flyable or showpiece form today.

Of the twenty-one aircraft delivered, eleven were lost and ten of these to accidents. With that said, the product was not a success for the storied SARO concern.

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Saunders-Roe A.36 Lerwick Technical Specifications

Service Year: 1939
Type: Reconnaissance Flying Boat
National Origin: United Kingdom
Manufacturer(s): Saunders-Roe (SARO) - UK
Production Total: 21

Structural (Crew Space, Dimensions and Weights)

Operating Crew (Typical): 6
Overall Length: 63.62 feet (19.39 meters)
Overall Width: 80.81 feet (24.63 meters)
Overall Height: 20.01 feet (6.10 meters)

Weight (MTOW): 28,506 lb (12,930 kg)

Installed Power and Standard Day Performance

Propulsion: 2 x Bristol Hercules II 140cylinder air-cooled radial engines developing 1,375 horsepower each.

Maximum Speed: 216 mph (348 kph; 188 knots)
Maximum Range: 1,541 miles (2,480 km)
Service Ceiling: 13,993 feet (4,265 meters; 2.65 miles)
Rate-of-Climb: 880 feet-per-minute (268 m/min)

Armament / Mission Payload

1 x 7.7mm machine gun in nose
2 x 7.7mm machine guns in dorsal turret
4 x 7.7mm machine guns in tail turret

Up to 2,000lbs (907kg) of depth charges, mines or bombs.

Global Operators / Customers

Canada; United Kingdom

Model Variants (Including Prototypes)

A.36 "Lerwick" - Base Series Designation; 21 units produced.