The Saunders-Roe A.36 Lerwick was a British flying boat built by Saunders-Roe Limited (Saro). It was intended to be used with the Short Sunderland in Royal Air Force Coastal Command but it was a flawed design and only a small number were built. They had a poor service record and a high accident rate; of 21 aircraft, 10 were lost to accidents and one for an unknown reason.
Design and development
Air Ministry Specification R.1/36 (to meet Operational Requirement 32) was issued in March 1936 to several companies that had experience in building flying boats. The specification was for a medium-range flying boat for anti-submarine, convoy escort and reconnaissance duties to replace the Royal Air Force's biplane flying boats such as the Saro London and Supermarine Stranraer. The specification called for a cruise speed of and a weight of no more than .
Designs were tendered by Saunders-Roe (S.36), Supermarine (Type 314), Blackburn Aircraft (b. 20) and Shorts. The Blackburn B.20 was a radical design which offered much better performance by reducing the drag associated with a flying boat hull, and so a prototype was ordered to test the concept. Of the other designs, the Supermarine was the first choice with Saro and Shorts tied in second place. The Supermarine was ordered "off the drawing board" (without requiring prototypes to be produced and flown first). Supermarine's commitment to the Spitfire meant that work was not expected to start for two years and so the Ministry looked to the other designs. Saunders-Roe had redesigned the S.36 in the meantime, replacing the low hull and gull wing with a deeper hull and a high wing, and the Supermarine order was transferred to the S.36. The contract was issued in June 1937 to buy 21, which was given the service name Lerwick (after the town of Lerwick). The aircraft was a compact twin-engined, high-winged monoplane of all-metal construction, with a conventional flying boat hull, a planing bottom and two stabilising floats carried under the wings on long struts. It was powered by two Bristol Hercules radial engines and initially had twin fins and rudders. For defence, the Lerwick was equipped with three powered gun turrets. The nose turret had a single 0.303 inch Vickers K gun; the other two had 0.303 Browning machine guns, two guns in the Nash & Thompson FN.8 turret in the dorsal position and four in the Nash & Thompson FN4.A turret in the tail. Offensive armament was a total of of bombs or depth charges; four or eight bombs, or four depth charges, carried in two streamlined nacelles behind the engines, similar to the Martin PBM Mariner.
The first three aircraft were used as prototypes, with the first being launched on 31 October 1938, after numerous delays during design and construction. The Lerwick was immediately found to be unstable in the air, on the water and not suited to "hands off" flying, a major problem in an aircraft designed for long-range patrols. Numerous adjustments, including the addition of a greatly enlarged single fin and an increase in the wing angle of incidence, failed to remedy its undesirable characteristics, which included a vicious stall and unsatisfactory rates of roll and yaw. In service, several aircraft were lost because of wing floats breaking off, suggesting this was a structural weakness. Persistent problems with the hydraulics resulted in bomb doors sometimes dropping open during flight.
On one engine the Lerwick could not maintain altitude or maintain a constant heading, as the controls could not counter the torque of one engine on maximum power. An engine failure would inevitably see the aircraft flying in slowly descending circles. On one occasion, the loss of an engine forced a Lerwick to make an emergency landing in the Caledonian Canal. The aircraft was then towed to Oban at the end of a string of coal barges.
Operational history
In mid-1939, four Lerwicks were allocated to 240 Squadron. By October, the squadron had stopped flying them and reverted to its older and slower Saro London flying boats. The Lerwick programme was cancelled on 24 October but restarted on 1 November. In December 1939, Air Vice-Marshal Sholto Douglas recommended that the Lerwicks be scrapped and Saunders-Roe put to building Short Sunderlands but the production change would have taken months and with the start of the Second World War, aircraft were urgently required.
thumb|Lerwick in the markings of 209 squadron
Production continued and the type entered service with 209 Squadron based at Oban in 1940, replacing Supermarine Stranraers. The squadron soon began losing aircraft to accidents. During the service with 209 Squadron, all the Lerwicks were grounded twice for urgent safety modifications; on only two occasions were U-boats attacked by a Lerwick and neither submarine was damaged.
In April 1941, 209 Squadron began receiving the US Consolidated Catalina. The last of a total of 21 Lerwicks was delivered in May but the type was withdrawn from front-line service in the same month.
Operators
;
- Royal Canadian Air Force
- No. 422 Squadron RCAF
- No. 423 Squadron RCAF
;
- Marine Aircraft Experimental Establishment
- Royal Air Force
- No. 209 Squadron RAF: 1939–1941
- No. 240 Squadron RAF : Three Lerwicks used for service trials.
- No. 4 (Coastal) Operational Training Unit: 1941
Specifications (Saro Lerwick)
Operational losses
Eleven of the 21 Lerwicks built were lost or written off during the three years the type saw operational service.
{|class="wikitable"
|+
|-
! width="80px"|Date
! width="100px" |Aircraft
! width="650px"|Cause of loss
|-
|align="right"|1 Sep 1939
|L7249
|Operating with the Marine Aircraft Experimental Establishment at Felixstowe, sank after launching as a camera hatch was left open; written off
|-
|align="right"|20 Feb 1940
|L7253 (WQ-G)
|Made an emergency touch–down in the Firth of Lorn, 5 miles west of Oban. A wing float broke off as it touched down, the aircraft rolled upside down and four crew died.
|-
|align="right"|21 Nov 1940
|L7251
|Sank at its moorings in Loch Ryan
|-
|align="right"|6 Dec 1940
|L7255 (WQ-A)
|Sank, when it lost a wing float in a gale while moored on Loch Ryan
|-
|align="right"|7 Jan 1941
|L7262
|Sank after an accident during take-off on Loch Ryan; two crew died.
|-
|align="right"|22 Feb 1941
|L7263 (WQ-L)
|Went missing while on patrol in good weather with a crew of 14
|-
|align="right"|14 Oct 1941
|L7268
|Operating with No. 4 (C)OTU, crashed into the sea near Tarbat Ness, following failure of the port engine.
|-
|align="right"|16 Oct 1941
|L7254
|Sank after striking a rock during taxi-ing
|-
|align="right"|21 Oct 1941
|L7248
|First Lerwick built. While on an <ABBR title="Marine Aircraft Experimental Establishment">MAEE</ABBR> calibration flight the starboard engine failed. Unable to maintain height on one engine, L7248 hit telegraph wires before crashing into a hillside above Faslane, killing six RAF personnel and a civilian technician. An investigation was unable to find the cause for the engine failure.
|-
|align="right"|11 Nov 1941
|L7257 (WQ-F)
|Sank at its moorings during a gale; salvaged in December 1941. Struck off charge in 1942 as being beyond repair
|-
|align="right"|21 Dec 1941
|L7265 (WQ-Q)
|Flying with No. 4 (C)OTU, it was written off after crashing during landing
|-
|align="right"|6 Sep 1942
|L7267
|Lost during an aborted landing, the pilot increased power to go-around but one engine failed to respond. A wingtip struck the water and the aircraft was spun around, opening a gash in the hull. The crew climbed out through the astrodome and swam toward shore as the aircraft sank, but were picked up by a boat
|-
|}
See also
References
Notes
Bibliography
- Bowyer, Chaz. Coastal Command at War. Shepperton, Surrey, UK: Ian Allan, 1979. . (p. 30.)
- Bowyer, Michael J.F. Aircraft for the Few: The RAF's Fighters and Bombers in 1940. Sparkford, near Yeovil, Somerset, UK: Patrick Stephens, 1991. . (pp. 148–151.)
- Burney, Allan. Flying Boats of World War 2 (The Aeroplane; & Flight Magazine Aviation Archive Series). London: Key Publishing, 2015.
- Buttler, T British Secret Projects: Fighters and Bombers 1935–1950 Midland Publishing. Hinckley. 2004. .
- Green, William. War Planes of the Second World War, Volume Five: Flying Boats. London: Macdonald, 1962 (Fifth impression 1972). . (pp. 84–87.)
- London, Peter. British Flying Boats. Sutton Publishers. 2003.
- London, Peter. Saunders and Saro Aircraft Since 1917. London: Putnam (Conway Maritime Press), London, 1988. .
- March, Daniel J. British Warplanes of World War II: Combat Aircraft of the RAf and Fleet Air Arm, 1939–1945. Hoo, nr Rochester, Kent, UK: Aerospace Publishing, 1998. . (p. 191.)
- Mondey, David. The Hamlyn Concise Guide to British Aircraft of World War II. Hamlyn (publishers),1982 (republished 1994 by Chancellor Press, reprinted 2002). . (p. 181.)
External links
- The Lerwick on History of War
- Lerwick on the site of the RCAF