Photograph:
Sikorsky S.42B Pan American Clipper NC16734 (c/n 4207) in Auckland Harbour, NZ in 1937 (Author’s collection)
Country of origin:
United States of America
Description:
Long-range commercial flying-boat airliner
Power Plant:
Four 492 kw (660 hp) Pratt & Whitney R-1690 Hornet nine-cylinder single-row supercharged air-cooled radial engines
Specifications:
- Wingspan: 34.79 m (114 ft 2 in)
- Length: 20.62 m (67 ft 8 in)
- Height: 5.28 m (17 ft 4 in)
- Wing area: 123.55 m² (1,330 sq ft)
- Max speed: 306 km/h (190 mph)
- Cruising speed at sea level: 257 km/h (160 mph)
- Cruising speed at 3,657 m (12,000 ft): 273 km/h (170 mph)
- Stalling speed: 105 km/h (65 mph)
- Rate of climb: 305 m/min (1,000 ft/min)
- Service ceiling: 4,877 m (16,000 ft)
- Range at cruising speed at sea level: 1,931 km (1,200 miles)
- Range with 680 kg (1,500 lb) payload at cruising speed at 1,829 m (6,000 ft): 4,827 km (3,000 miles)
- Fuel capacity: 4,693 litres (1,032 Imp gals)
- Empty weight: 8,965 kg (19,754 lb)
- Useful load: 8,272 kg (18,236 lb)
- Loaded weight: 17,237 kg (38,000 lb)
History:
The S.42 was a commercial flying boat designed by Igor Sikorsky to meet a requirement of Pan American World Airways, Juan Trippe, president of Pan Am, requesting in June 1931 designs from six aircraft manufacturers for an aircraft able to span the world’s oceans. It was a development of the S.40 and had major aerodynamic improvements including wing flaps, variable pitch Hamilton Standard propellers, and Pratt & Whitney supercharged radial engines.
On 1 October 1932 Pan American placed an order for three S.42s, with an option on a further seven. The prototype flew for the first time on 29 March 1934 and during testing it established ten world records for payload to height. It received a number of names, including The Flying Clipper and Pan Am Clipper. However, it was revealed it could not meet the Company’s range requirements and, to fly across the Atlantic or Pacific Oceans, it had to be fitted with extra fuel tanks and all accommodation had to be removed. Main services provided by the type were Miami to Rio de Janeiro, New York to Bermuda, and Seattle to Alaska.
A company was set up in Britain to build the S.42A under licence known as British Marine Aircraft Ltd, a facility being set up on the Hamble Peninsula with a slipway to Southampton Water but the project did not proceed. Later the facility was sold and became the factory for Folland Aircraft Ltd. The British variant was to be known as the British Marine BM.1.
A total of ten S.42s was delivered, all manufactured at the Vought Sikorsky Aircraft Division of United Aircraft Corp in Stratford, Connecticut. The first was delivered to Pan Am and, named Pan Am Clipper, surveyed a route from the US west coast to China, from Alameda in California to Pearl Harbour, and to Hawaii. First scheduled service was in March 1939 from Miami to Rio de Janeiro via San Juan, Port of Spain, Belem, Recife and return. One example was acquired by the US Navy for operation as a transport.
Three variants were produced: the S.42, with three delivered as NC822M, NC823M and NC824M, these having the 522 kw (700 hp) Pratt & Whitney S5D1G engines; the S.42A with 559 kw (750 hp) Pratt & Whitney S1EG engines, four being delivered as NC15373, NC15374, NC15375 and NC15376; and the S.42B with some aerodynamic improvements, Hamilton Standard constant-speed propellers, and an increase in take-off weight, three being delivered as NC16734, NC16735 and NC16736.
A couple were lost in accidents. Puerto Rican Clipper crashed on take-off from Port of Spain on 11 April 1936 when the aircraft turned to avoid a fishing boat in its path, a wing float hitting the boat and the aircraft overturning. Samoan Clipper [formerly Pan American Clipper II] exploded on a flight to Auckland, New Zealand on 11 January 1938. After take-off engine problems were encountered. An attempt was made to dump fuel so an emergency landing could be safely made; however the aircraft exploded.
Dominican Clipper crashed on landing in the harbour at San Juan, Puerto Rico on 3 October 1941 and was destroyed. Hong Kong Clipper II [formerly Bermuda Clipper and Alaska Clipper] was destroyed by Japanese aircraft at Kai Tak Airport in Hong Kong on 8 December 1941. Hong Kong Clipper [formerly West Indies Clipper and Pan Am Clipper I] when flying from San Juan to Miami, Florida crashed on take-off from Antilla, Cuba and was destroyed.
First of the type seen in this part of the world was S.42B Pan American Clipper which landed on Waitemata Harbour, Auckland on 31 March 1937, the aircraft NC16734 being flown by Captain Edwin C Musick with a crew of seven, this being a pioneering flight across the Pacific from San Francisco. At that time it was the largest aircraft to visit New Zealand. The flight stemmed back to August 1935 when Pan American Airways approached the New Zealand Government with a proposal to operate scheduled services between the United States and New Zealand as an extension of its already operating routes across the Pacific to China and the Philippines.
The crew released information from the logbook of the flight, this being: San Francisco to Honolulu – [3,879 km] 2,410 miles in 18 hrs 48 mins; Honolulu to Kingman Reef – [1,722 km] 1,070 miles in 8 hrs 5 mins; Kingman Reef to Pago Pago – [2,494 km] 1,550 miles in 10 hrs 35 mins; Pago Pago to Auckland [2,977 km] 1,850 miles in 11 hrs 52 mins – a total of [11,072 km] 6,880 miles in 49 hrs 20 mins. During ceremonies and discussions for the following few days invited guests were taken on a sight-seeing flight along the east coast of New Zealand as far as Napier. Harold C Gatty, Australian navigation and aviation pioneer, was employed at the time as the New Zealand representative for Pan American.
The new service to New Zealand was to commence on 31 December 1936. The start-up of the service was delayed but land at Mechanics Bay was leased from the Auckland Harbour Board. Pan Am staff were employed. The Pan American Clipper arrived in Auckland with Captain Musick on board, staying until Sunday, 4 April, when it flew to Pago Pago after a flight of 12 hrs 16 mins. This aircraft, later that year renamed Samoan Clipper, landed on Waitemata Harbour on 26 December 1937 and the crew was afforded a civic reception at the Auckland Town Hall.
At this time Captain Musick announced that Pan American was obtaining examples of the new Boeing 314 flying-boat which could seat 70 passengers, having an all-up weight of 37,195 kg (82,000 lb) compared with the 19,958 kg (44,000 lb) of the S.42B. Samoan Clipper departed Auckland at 3 am on 2 January 1938 and reached Pago Pago after 12 hrs 36 mins. It flew on, arriving at Honolulu on 3 January. Six days later it departed for a return flight to Kingman Reef, Pago Pago and Auckland. A fortnightly service was to be launched from 9 January 1938 stopping at Honolulu, Kingman Reef to refuel, and on to Pago Pago where a night stop would be made.
The Samoan Clipper aircraft [NC16734] took off at 5.30am on 11 January but reported engine problems with an oil leak and decided to return to Pago Pago. Fully loaded with fuel for the flight to Auckland, it was too heavy to land safely in the small harbour and the pilot decided to dump fuel. At some point during this operation the fuel ignited and the aircraft was seen to descend rapidly in flames and explode, falling into the sea, with the loss of life of all on board.
Further services were delayed until Pan American introduced the Boeing 314 and the first of these, NC18602 California Clipper, flown by Captain John H Tilton, arrived in Auckland Harbour commencing a weekly service which continued until the Japanese attack on Pearl Harbour.