Country of origin:

United States of America

Description:

Two-seat long-range mail plane

Power Plant:

One 530 kw (710 hp) Wright SR-1820-F3 nine-cylinder air-cooled radial engine

Specifications:

History:

In the early 1930s Northrop Corp, which at this time was operating from a facility at Mines Field at Los Angeles Municipal Airport, designed and built the single-engine Delta, which was an enlarged Alpha. However, at the same time the new Company built two Model 2 Gammas, being single or two-seaters with provision for the carriage of mail or express freight. In the event, seven Gammas were built, along with several variants aimed at the military market.

Construction was all-metal. The semi monocoque fuselage was of circular cross-section on top of the centre section. It was designed to take engines in the 522 kw (700 hp) to 746 kw (1,000 hp) range. One example, the 2-D was modified for high-altitude flights, and, flown by D W Tomlinson, reached 10,668 m (35,000 ft) gaining useful data. American pilot Frank Hawks set many trans-continental and inter-city speed records in a Gamma (NR12265).

The first aircraft built, a Gamma 2A (NR12269 – Polar Star – Ellsworth Trans-Antarctic Flight) with a 522 kw (700 hp) Wright engine, was used in the Antarctic by noted American Antarctic explorer, Lincoln Ellsworth. Advisor to the exedition was Australian Sir Huber Wilkins. The first attempt was mounted in 1934. The aircraft was shipped to New Zealand on the vessel Wyatt Earp, arriving at Port Chalmers in Dunedin in either November or December 1933 with the monoplane strapped to the bow of the ship. The vessel passed through a typhoon on the trip to Antarctica. It was taken ashore where engine runs were made on the Rattray Street wharf without the wings installed. After reloading on board it was shipped to Antarctica’s Bay of Whales.

The first attempt to cross the polar ice proved to be a near disaster when the section of the Ross Ice Shelf on which the aircraft and supplies had been unloaded broke into separate floes and the crew and the aircraft had to be rescued by the crew of the vessel. On this occasion the aircraft suffered damage and had to be repaired, arriving back in Dunedin, NZ on 28 January 1934. It was returned to the US, repaired and again shipped to New Zealand before being shipped south.

A second attempt was made, the team basing itself on Deception Island in the South Shetlands, but on this occasion a broken connecting rod in the Pratt & Whitney Wasp engine forced cancellation of the attempt. A third attempt was planned but the expedition pilot refused to fly in the prevailing weather conditions. The flight that was made failed and, due to the onset of the Antarctic winter, the attempt was cancelled.

A further attempt was made, this time with an English pilot, Herbert Hollick-Kenyon. The aircraft took off on 21 November 1935 in an attempt to fly from Dundee Island on the northernmost shore of the Weddell Sea to Little America on the Ross Ice Shelf, a distance of 3,701 km (2,300 miles). After travelling 966 km (600 miles) the crew of Hollick-Kenyon and Ellsworth had to turn back due to problems with the fuel gauge. On 22 November they left again and flew over what would become the Ellsworth Mountains, and across what became the Hollick-Kenyon Plateau. After travelling 2,897 km (1,800 miles) in a time of 14 hours the crew landed and raised the American Stars and Stripes flag. After being on the ice for 19-hours they took off again but had to land due to poor visibility.

They remained on the ice for eight days, living in a small tent. Eventually they dug the aircraft out, took off, flew for four-hours, and landed 201 km (125 miles) from the Bay of Whales to refuel. They resumed the journey but had to land due to the aircraft getting low on fuel. They decided to walk what they believed was 5.6 km (3.5 miles) to Little America, but after covering 24 km (15 miles) returned to the aircraft. Over a period of nine days they eventually reached Little America on 15 December.

A search commenced for the crew and the aircraft, the vessel Wyatt Earp, having lost radio contact with the aircraft.  In Australia the vessel Discovery II was prepared to mount a rescue and a RAAF Westland Wapiti (A5-37) and de Havilland DH.60 Gipsy Moth (A7-1) were loaded on board, both being fitted with floats, the vessel leaving from Melbourne on 23 December. On the journey south skis were built for the aircraft by the crew. The crew of the Gamma was located by the pilot of the DH.60 and rescued, the aircraft being returned to the United States where, on 25 April 1936, it was presented to the National Air & Space Museum in Washington DC, where it still resides.

Another Gamma has a faint local connection. This aircraft named Texaco 20 (N13759) was the 6th civil Gamma built and was a model 2-G two-seater built for American aviatrix Jacqueline Cochrane for the 1934 MacRobertson Air Race from England to Australia held in October 1934. This machine was fitted with a 522 kw (700 hp) Curtiss G1V-1570 Conqueror geared and super-charged liquid-cooled engine. However, during its delivery by a ferry pilot to New York for shipment, the supercharger failed over Texas and the aircraft was damaged in the subsequent forced landing.  As it could not be repaired in time for shipment to England, Cochrane had to change to another aircraft type. The aicraft was also return from the Antarctic to the United States along with Polar Star but ended up as a patol aircraft during the Spanish Civil War.

A further Gamma was named Texaco 20. It was flown to Rio Gallegos to install the floats from the Polar Star flown by Lymburner and Dick Merrill. The Wyatt Earp  proceeded to Cape Horn.  The Australian Government dispatched its Antarctic research vessel Discovery II  from Melbourne on 23 December equipped with two aircraft with sledges, de Havilland Gipsy Moth A7-1 and Westland Wapiti A5-37 flown  by Fl Lt Eric Douglas and Flying Officer Alister Murdock of the RAAF.

There were any problems experienced during the Ellsworth expedition.  He left the Antarctic on board the Discovery II . The Polar Star  and the  Texaco 20 were eventually shipped back to the United States on the Wyatt Earp to Brooklyn. The Polar Star was presented to the Smithsonian Institute on 25 April 1936 and placed on display.