The Lockheed R5O was the US Navy’s designation for the Model 18 Lodestar transport, of which nearly 100 were used during the Second World War.
The US Navy was the first branch of the American military to order the Lodestar, placing orders for one XR5O-1, two R5O-1s, one R5O-2 and two R5O-3s during 1940.
The XR5O-1 was a staff transport ordered for the US Coast Guard. It was powered by 1,200hp Wright Cyclone engines, and was based on the civil Model 18-40. After the Second World War it went to South Africa for a period, before returning to the United States.
The two R5O-1s were staff transports ordered for the US Navy. Like the XR5O-1 they were based on the Model 18-40 and powered by two 1,200hp Wright R-1820-97 engines.
The R5O-2 was a single Model 18-07, powered by two 850hp Pratt & Whitney R-1690-25 engines. It was delivered to the US Navy in the autumn of 1940 and was the first R5O to enter Navy service.
The two R5O-3s were similar to the civil Model 18-10, and were powered by 1,200hp Pratt & Whitney R-1820-40 engines. They were originally laid out as VIP transports, with space for four passengers in luxurious accommodation. They were later modified to carry more passengers in less comfort.
The Navy also gained a larger number of R5Os during the Second World War, some taken from civil service and some from a large USAAF order for the C-60 variant.
The R5O-4 was the designation given to twelve Cyclone powered Model 18-56s, powered by 1,200hp Wright R-1820-40 engines. They were impressed by the Navy while still under construction, and were completed as seven seat naval staff transports.
The R5O-5 was the designation given to forty-one similar aircraft, also based on the Model 18-56 and powered by Cyclone engines, but laid out as less comfortable naval staff transports, capable of carrying fourteen people.
The final version was the R5O-6 eighteen-seat paratroop transport. They were taken from a batch of C-60A-5-LOs being built for the USAAF. Thirty five were given to the Navy and mainly went to the Marine Corps.
Wing span: 65ft 6in
Length: 49ft 10in
Gross weight: 18,500lb
Maximum weight: 143,600lb
Maximum speed: 250mph
Lockheed Aircraft Since 1913, René J Francillon