Country of origin:

Germany

Description:

Commercial transport

Power Plant:

Three 392 kw (525 hp) Pratt & Whitney Hornet nine-cylinder air-cooled radial engines

Specifications:

History:

The Junkers G 31 series of commercial transports was one of the success stories of the 1930s, and its operation in New Guinea in the freight role has gone down as one of the important annals in aviation history. The G 31 was designed by Dipl Ing Ernst Zindel, the prototype D-1073 (c/n 3000), powered by three 209 kw (280 hp) Junkers L-5 six-cylinder liquid-cooled engines, flying for the first time in September 1926. It was described by Junkers as the airliner for long distance travel. It underwent much development and modification, and was powered by a variety of engines. At one stage the prototype was fitted with three 373 kw (500 hp) BMW VI radial engines.

Of all-metal construction, the cabin was divided into three equal-sized compartments, with accommodation for fifteen passengers with a crew of either two or three. A number of long distance flights were made, including, in March 1927, from the Junkers factory at Dessau in Germany through southern Europe, visiting Vienna, Venice, Rome and Madrid, a distance of 6,000 km (3,730 miles); and in September that year a flight to Asia covering 5,000 km (3,100 miles). This flight was via Moscow to Persia (now Iran) with 1,500 kg (3,307 lb) of medical supplies.

The first G 31de delivered, D-1310 (c/n 3002), went to Luft Hansa in February 1928 and the type was operated on the Berlin–Hamburg –Amsterdam–London and Berlin–Danzig–Koenigsberg routes. Early production aircraft had 380 kw (510 hp) Gnome-Rhone Jupiter VI engines. The first G 31de for Osterreichische Luftverkehrs AG (A46 – later OE-LAG – c/n 3003) was the 1,000th Junkers aeroplane and entered service in 1928. These two airlines were the main operators of the type on passenger services.

Further variants were released, including the G 31fi with 380 kw (510 hp) Siemens Jupiter VI engines. Three G 31fis were built in anticipation of orders but, as the orders were not forthcoming, were modified to G 31go standard for services in New Guinea. One G 31ho had one Pratt & Whitney and two BMW Hornet radials, each with a four-blade propeller.

The G 31s were regular visitors to Croydon airport in London, UK. On these flights up to 18 passengers could be carried; and one variant was made available as an air ambulance, with 12 berths and four seats.

With the discovery of gold near Wau in the 1920s, Bulolo Gold Dredging required an aeroplane capable of operating into landing grounds at Lae, Salamaua, Bulolo and Wau, PNG. Dredges weighing more than 1,000 tons were required and these were dismantled and flown over the mountains in the G 31s. The first two aircraft were Model G 31go and were for Bulolo Gold. VH-UOU ‘Bulolo 1 Paul’ (c/n 3011), fitted with three 373 kw (500 hp) Pratt & Whitney Hornet A21 engines driving three-blade propellers, was registered on 25 May 1931; and VH-UOV ‘Bulolo 2 Peter’ (c/n 3012) with the Hornet engines was registered on 10 June 1931. A further machine was obtained by Guinea Airways, VH-UOW (c/n 3010), with similar engines, and was registered on 10 June 1931. The cargo hold measured 7.31 m (24 ft) in length, 1.98 m (6 ft 5 in) in width and 1.79 m (5 ft 9 in) in height. The G 31 had an open cockpit and tailwheel in place of the usual skid.

The first machine (VH-UOU) arrived in Lae on the ‘SS Temeraire’ in December 1930, the other two in February 1931. Normal payload was 2,631 kg (5,800 lb) but, as the trip from Lae to Bulolo was only 42 mins, the payload was increased to 3,221 kg (7,100 lb). In 1935 VH-UOW carried 4.26 m (14 ft) long shafts, each weighing 3,425 kg (7,550 lb). In 1933 Bulolo Gold Dredging Ltd bought the prototype G 31go VH-URQ (c/n 3000). It was named ‘Pat’ and was operated for the owners by Guinea Airways Ltd. It was fitted with 392 kw (525 hp) Pratt & Whitney Hornet A2 engines and was registered 9 June 1934.

On 27 July 1933 a record was set by one machine, flying six Lae to Wau round trips carrying 16.68 tons (16,948 kg / 37,363 lb). Operations continued until 21 January 1942. On this occasion two, ‘Peter’ and ‘Pat’, were refuelling at Bulolo pending their use for the evacuation of personnel to Australia. At 12.30 pm ‘Paul’ had just arrived from Lae when Japanese Mitsubishi A6M fighters attacked the strip, strafing the area for 15 minutes, and three of the Junkers transports (VH-UOU, VH-UOV and VH-URQ) were destroyed. At the time VH-URQ had just arrived from Lae with a cargo of beer for the troops and most of the latter was destroyed when the aircraft burst into flames.

VH-UOW was evacuated to Australia and impressed by the Royal Australian Air Force (RAAF) as A44-1 on 30 January 1942. It was used by No 1 Communications Flight, and was fitted out as an air-ambulance at No 1 Aircraft Depot (AD). In March 1942 it was noted in RAAF markings at Essendon, VIC. However, it was damaged in an accident on 31 October 1942 whilst with No 36 Squadron when it was en-route to No 34 Squadron, the starboard engine failing on take-off, the aircraft hitting a road roller, running through a hedge and coming to rest outside the aerodrome on a road. Due to a lack of spare parts, it was taken off strength and was eventually scrapped, approval being granted to convert it to components at No 1 AD on 14 May 1943.