The Polaris Expedition: Short S.24 Surveyor
Specifications:
Crew: Two (Pilot and Co-Pilot/Navigator)
Length: 14.67 m
Wingspan: 22.3 m
Height: 5.07 m
Empty Weight: 11,413 lb (5,177 kg)
Gross Weight: 16,350 lb (7,416 kg)
Powerplant: 4x Napier Rapier VI 16-cylinder "H-block" piston engines, 365 hp (272 kW) each
Propellers: 2-bladed fixed-pitch propellers
Performance:
Never-Exceed Speed: 180 KIAS
Cruise Speed: 155 KIAS
Range: 4,850 nmi
Service Ceiling: 15,000 ft
In late 1936, a pair of explorers with the Royal Geographic Society contacted the Short Brothers in regards to the construction of a specialty flying boat. They were Kathryn Horrocks of Manchester and Thomas Westby of Birmingham. Starting in 1934, the pair had been planning an expedition to the geographic North Pole by aircraft which sought to be not only the first flight over the North Pole in an airplane but also the first landing at the North Pole and first woman to reach the Pole.
The aircraft requested from Shorts was to have a range in excess of 3,000 nautical miles, space for the two person crew plus consumables, and be capable of landing both on water and on ice/snow. At the same time, Shorts was in development of the Short Mayo Composite system, which consisted of a modified Short Empire flying boat (the Short S.21 Maia) and a two-person floatplane mounted on the top of the flying boat’s fuselage (the Short S.20 Mercury). Intended for airmail routes, the Mercury alone had a range of 3,400 nautical miles and, due to its size, would be easy to handle in the Norwegian fjords that the crew intended to use as staging points. However, because the Mercury was on floats, access to the aircraft while landed on the ice cap would be very difficult especially when carrying supplies and equipment necessary for the Polar expedition.
Shorts’ solution? Convert the basic S.20 airframe into a flying boat. The final design was presented to Horrocks and Westby in May 1937, and officially ordered the same day. Then, just as the expedition was beginning to take shape, tragedy struck. On 18 June 1937, a Soviet expedition led by Valery Chkalov set off to overfly the Pole in a Tupolev ANT-25, marking the first successful flight over the Pole by airplane. As this was one of Horrocks and Westby’s expedition’s main goals, they were devastated. Construction of their aircraft was paused after only a month while the expedition, by this point known as Polaris, determined whether they should still attempt the flight. After a month of deliberation, it was decided that the expedition should proceed and attempt to accomplish its other goals of first landing and first woman at the Pole, and construction resumed.
By February 1938, the aircraft was ready for its first flight. The newly-designated S.24 Surveyor took flight from Shorts’ facility at Borstal, near Rochester, piloted by Shorts test pilots. After a brief working-up and checkout by Shorts, Horrocks and Westby first flew the aircraft themselves on 28 March. In addition to conversion into a flying boat, the S.24 featured several other differences from its S.20 cousin. Notably, the S.24 featured a slightly enlarged wing and the addition of split flaps for increased takeoff and landing performance. Also fitted was a dome on the mid fuselage for navigating by sextant and ADF equipment for radio navigation. By October the S.20 was being modified to increase its range, modifications that were also done to the S.24. This increased the S.24’s range to a whopping 4,850 nautical miles, allowing the Polaris Expedition to make less frequent fuel stops on the way to and from the Pole.
In early 1939, the aircraft was ferried from Borstal to RNAS Felixstowe, where the expedition would begin. Training and preparation continued throughout the winter and early Spring, and the departure date was finalized as 13 April 1939. After departing Felixstowe, the expedition made stops in the Netherlands and Denmark before transiting up the Norwegian coast to Narvik, arriving on 2 May. After additional navigation calculations and refueling, the expedition followed the coast to Skjervoy before setting out across the Barents Sea to Svalbard, arriving in Longyearbyen at 1am local on 4 May. After another few days waiting for weather to clear, the Polaris Expedition set out on their final leg to the North Pole on 7 May 1939, making their first landing at 6:45pm local. Believing they had arrived at the Pole, a camp was set up which Horrocks and Westby used as a base of operations for an exploration of the surrounding area for the next 10 days, departing in the early hours of 18 May for Svalbard.
It wasn’t until their return leg that the expedition realized something had gone wrong. Intending to arrive back in Longyearbyen, the aircraft instead made landfall on Kvitoya over 200 nautical miles away. Additional calculations were made and it was discovered that their original route planning had not correctly accounted for the high winds aloft near the Pole and they had actually landed some 65 nautical miles away. Crushed, the expedition lacked the fuel for another attempt and thus made for Svalbard, arriving on 21 May. Retracing their steps down the Norwegian coast, Horrocks and Westby arrived back in Felixstowe on 9 June to massive fanfare, despite their failure to reach the Pole. The expedition was heralded for their journey and successful exploration of the ice cap, though there was a lingering feeling of failure in Horrocks and Westby.
Not to be deterred, another expedition was immediately greenlit and planning began for a second attempt in Spring 1940. However, due to the outbreak of war in Europe, this expedition never occurred. Westby joined the RAF as a navigator and was killed in action over Italy in 1943. Horrocks spent the war as a member of the Air Transport Auxiliary, conducting ferry flights around the British Isles. After the war, she did not attempt another Polar expedition and instead worked as a flight instructor in her hometown of Manchester. She died in 1983 at the age of 76. The sole S.24 Surveyor was acquired by the RAF and was used alongside its S.20 cousin by No. 320 (Netherlands) Squadron RAF before being transferred to No. 119 Squadron RAF in 1941. The aircraft flew little during this time, and was eventually scrapped in 1944. A replica S.24 is under construction by a group led by Horrocks’ granddaughter and is expected to fly in Spring 2024 for the 85th anniversary of the Polaris Expedition.
A route map and alternate RAF scheme for the S.24 (not a part of the entry) can be found in FD AU 5, here: http://shipbucket.com/forums/viewtopic. ... 99#p210399
