Chase Aircraft designed the first all-metal transport glider, the
XCG-18, followed by the larger and more efficient MS-8 Avitruk model.
This was ordered on March 5, 1948 by the USAF in both piston-powered
and un-powered forms as the XC-123 (47-786) and XG-20 (47-787). The
first flights were made at October 14, 1949 and April 26, 1950 respectively.
The XG-20 had a design maximum T/O weight of 70,000 lb, but there was
no tow aircraft available to pull this load, so it was restricted to
40,000 lb. After some gliding trials the XC-20 was modified to become
the first American jet-powered transport aircraft, when fitted with
two B-47 inboard engine pods containing four General Electric J47
turbojets. It flew in this configuration for the first time on April
21, 1951 as the XC-123A. Thus this design became the first to fly
as a glider, a piston-powered aircraft and a jet transport.
The other prototype, the XC-123, powered by two 2,500 hp Pratt &
Whitney R-2800-52W Double Wasp engine, proved successful, so the USAF
issued a contract for 300 C-123B Provider transports. Chase did not
have the facilities for large-scale production, the Kaiser-Fraser
Corp. received the contract. This contract was withdrawn due to
commitment problems, so finally the contract was awarded to Fairchild
and a total of 303 were build, the first flew September 1, 1954.
Service operations started in July 1955; 6 were exported to Saudi
Arabia and 18 to Venezuela.
Numerous changes were made in the design during production, this
included a large dorsal fin, redesigned rudder and elevator,
paratroop doors, etc. The Thunderbirds used a C-123B (54-0671) as a
An attempt to improve performance was the addition of two 1,000 lb
(454 kg) s.t. Fairchild J44 jet engine in the wingtips of the first
C-123B. This resulted in the modification of ten production aircraft
to C-123J. Another modification was the fitting of a wider tread main
gear, the small number of aircraft modified so were known as C-123H's.
When the C-123B was send to the Southeast Asia war-theatre the
aircraft finally came into its own, flying the assault transport
mission it was designed for, operating from hastily constructed
strips. The UC-123B was used to spread defoliant over forests thought
to give cover to the Vietcong.
The prototype YC-123H was fitted with two 2,850 lb (1,293 kg) s.t. General
Electric CJ610 jet engines mounted in pods slung from the wing and
flown on 30 July 1962. Tested in South Vietnam for counter-insurgency
operations this configuration proved successful and from 1964 on 183
more C-123B were fitted with J85-GE-17 (military counterpart of the
CJ610) as auxiliary power. Designated C-123K these were extensively
used for airlift missions. Some were further converted to AC-123K
The successor to Chase Aircraft, Stroukoff Aircraft, obtained
contracts for Boundary Layer Control on the XC-123D (52-1627), flown
in December 1954. This same aircraft being converted again into the
YC-134 for the "Pantobase" project with retractable
hydro-skis and flotation pontoon under each wing.