On April 11,1936 the Soviet Council of Labor and Defense (SRT) of the USSR decided to purchase aircraft manufacturing licenses and technical assistance from the US to help ease an apparent backlog of aviation needs in the massive country (11 time zones long). Because of the long range requirements to cover the expanse, a large and small aircraft combination was sought and the Soviets selected the Consolidated Model 28 (PBY Catalina) and the still to be built Martin 156 “Russian Clipper.
Design and development
Martin delivered three Martin Ocean Transport Model-130s (M-130) to Pan Am in 1935 which were flown as the China Clipper, Philippine Clipper and Hawaii Clipper. Pan Am rejected the M-156 in preference to the Boeing 314 for its replacement.

Pan Am was seeking to expand its trans-Pacific air service between San Francisco and Hong Kong in 1937. This route had been pioneered by the Martin M-130 and Pan Am was in need of a larger aircraft. The San Francisco to Hawaii flight was 2,400 mi (3,900 km) and took 18 – 20 hours. Pan Am would have configured the M-156 as a 26-berth sleeper. The trans-Pacific flights flying Hawaii -Midway Islands - Wake Island - Guam - Manila - Hong Kong were less than half the California to Hawaii leg. With a lower fuel load requirement, the M-156 could carry additional passengers. The M-156 would have been converted to a 33- to 56-seat day trip configuration. Pan Am and Matson Liners advertised an "Air-Sea Cruise" where Matson Liners carried passengers from San Francisco to Honolulu. Passengers would then transfer to Pan Am Clippers for westward flights to China and the Orient.

After Pan Am selected the Boeing 314, Martin negotiated a deal with the Soviet Union for this aircraft and the M-156 was never put into regular trans-Pacific service. The M-156 was sold to the Soviets and operated by Aeroflot on the Soviet Union's far-east routes under the designation PS-30.

Like the M-130, the M-156 was a four-engined, parasol wing design. While the M-156 retained the same length as its predecessor, its wingspan was increased by more than 27 ft (8.2 m) with the addition of flaps for increased control. The M-156 also differed from the M-130 by having a horizontal stabilizer mounted atop a pylon at the rear of the hull, with twin vertical stabilizers and twin rudders located atop the horizontal stabilizer.

Along with the increase in wing size, fuel capacity was expanded from the M-130's 3,165 gal (11,981 L) to a total of 4,260 gal (16,126 L) in the M-156/PS-30. Power for each of the four engines increased from 850 hp (630 kW) to 1,000 hp (750 kW) utilizing the more powerful Wright Cyclone G2 radials.

A Soviet crew flew to Maryland led by engineer Borisenko and pilot Ershov Kozlova on December 14th to observe the sea trials and Maximum speed: 182 mph (293 km/h, 158 kn)
Range: 3,000 mi (4,830 km, 2,600 nmi) performance of the largest passenger aircraft in America and by January 20th, she was on her way to the other side of the world.

The Russian Clipper was first flown to New York and then dismantled and boxed up to be placed onto an awaiting steamship direct to Leningrad. Some parts of the clipper like wings and fuselage were too large so they were secured on deck and tied down.







The single M-156/PS-30 was put into regular service in 1940 by Aeroflot and was utilized in the Soviet Far East along the Pacific coast.
Aeroflot configured the aircraft to carry up to 70 passengers. It was flown by Aeroflot until 1944, at which time it was scrapped




Specifications (Martin 156C)
General characteristics
Capacity: 53 passengers (San Francisco - Hawaii)
26 passengers (San Francisco - Hong Kong)
Length: 92 ft 2 in (28.11 m)
Wingspan: 157 ft 0 in (47.87 m)
Height: 27 ft 2 in (8.29 m)
Empty weight: 31,292 lb (14,194 kg)
Gross weight: 60,708 lb (27,561 kg)
Powerplant: 4 × Wright R-1820 Cyclone G2 radial piston engine, 1,000 hp (750 kW) each
Performance
Maximum speed: 182 mph (293 km/h, 158 kn)
Range: 3,000 mi (4,830 km, 2,600 nmi)