The Martin RM-1/ C-3 was the designation given to two Martin 4-0-4 airliners that served with the US Coast Guard and then the US Navy.
The Martin 4-0-4 was a twin engine civil airliner that was originally developed as the 2-0-2 in the late 1940s. This was a twin engine aircraft with low mounted wings and tricycle landing gear. The first aircraft entered service in October 1947, but one was lost as a result of wing failure in 1948 and production of the 2-0-2 ended. Martin had already begun work on a modified 3-0-3, but after the failure of the 2-0-2 this was abandoned in favour of a more advanced version, the 4-0-4. This introduced the new wing designed in response to the 1948 failure and had a pressurized fuselage. The 4-0-4 was a moderate commercial success, with 103 built in total by the time construction ended in 1953.
Only two examples of the 4-0-4 entered US military service. These were ordered by the Coast Guard in 1951 as logistics support aircraft, with the designation RM-1G, and the Coast Guard serial numbers 1282 and 1283. By the time they were delivered in 1952 their role had been changed to VIP transports, and their designation to RM-1Z.
The two aircraft were still in use in 1962 when they were re-designated as the VC-3A. They were transferred to the US Navy in 1969, where they became the VC-3A. They were given the Navy serial numbers Bu158202 and Bu158203. However their Naval career was short, and they were withdrawn in 1970.
Engines: Two Pratt & Whitney R-2800-34
Power: 2,400hp each
Span: 93ft 3in
Length: 74ft 7in
Empty Weight: 24,000lb
Gross weight: 44,900lb
Max speed: 312 mph
Cruising speed: 280mph
Service ceiling: 30,000ft
Range: 1,800-2,600 miles