30 January 1933 saw the first flight of the Curtiss T-32 Condor II, a fabric-skinned biplane developed against an American Airways requirement for a 12-seat luxury sleeper transport for overnight multi-stop services across the United States. A little over a week later, the all-metal Boeing 247 made its first flight from Seattle and was followed in May 1934 by the Douglas DC-2. The arrival of these faster, state-of-the-art monoplanes gave United and Transcontinental & Western a significant commercial advantage over American; and, in 1936, Curtiss set about designing an aircraft to compete with them. Conceived as a larger and faster alternative to the DC-3, the CW-20 had two particular selling points: it was pressurised, so could fly above bad weather, and it incorporated the new concept of a separate underfloor cargo hold, thus freeing up cabin space to accommodate up to 34 passengers compared with the DC-3’s 21. But development was slow and with war in Europe well under way by the time of the first flight, no commercial order was forthcoming. However, the CW-20’s large volume cargo capacity found favour with the United States Army Air Corps which placed its first order in September 1940, giving the CW-20 the name Commando. Ultimately, the entire production run went to the United States military, and the type served in most theatres during World War II, most impressively on re-supply flights across the Himalayas from India to China. While a small number remains active in Alaska and Canada (and one remains on the air show circuit in the United States), over half of the survivors are on static display.
First flight: 26 Mar 40 (c/n 101, NX19436)
Production: 3,180: 2,711 at Buffalo, NY; 28 at St. Louis, MO; 439 at Louisville, KY; and 2 by Higgins Industries at New Orleans, LA
First delivery: 28 Jun 42, to US Army Air Corps (c/n 26362, 41-5160)
Last delivery: 28 Feb 46, to US Army Air Force (c/n 22768, 44-78945)
Variants: CW-20 - prototype civil airliner powered by 2 Wright R-2600 Cyclones, featuring twin tails (subsequently re-engineered with a single fin) (1 built, at St. Louis);
CW-20A/C-46 - initial military version with pressurisation removed, powered by 2 Wright R-2800 Double Wasps (25 built, at Buffalo);
CW-20B/C-46A - C-46 with double cargo doors, strengthened floor, cargo winch and accommodation for 40 troops (1,942 built, comprising 1,041 at Buffalo, 439 at Louisville, 10 at St. Louis and 2 at New Orleans; 160 were transferred to the US Marine Corps as R5C);
CW-20B-2/C-46D - C-46A optimised as a paratroop carrier with revised doors and accommodation for 50 troops (1,410 built at Buffalo);
CW-20B-3/C-46E - C-46A with single cargo door, stepped windshield, three-bladed Hamilton propellers and control boost system deleted (17 built at St. Louis)
CW-20B-4/C-46F - C-46A with three-bladed props, and control boost system deleted (234 built at Buffalo);
CW-20B-5/C-46G - C-46F with uprated engine, subsequently converted to XC-113 to test the TG-100 gas turbine engine (1 built at Buffalo).
Conversions: Super 46 - C-46 modified by Air Carrier Engineering & L.B. Smith Aircraft, Miami, FL.with higher gross weight and powered by Wright R-2800C engines (first flight, Sep 55).