The
Sikorsky S-55 first flew in 1949 and was the first Sikorsky
helicopter with enough lifting ability to allow satisfactory
operation as a troop transport. With its radial engine in the
nose, enough space was left free in the cabin for passengers or
cargo. Known as the H-19 Chickasaw by the Air Force and
Army, the HO4S by the Navy and the HRS by the Marines,
this helicopter was used by all U.S. military services in the 1950s
and 60s.
The S-55 was license built by SNCA du Sud Est in
France and by Westland in the United Kingdom (marketed under the
name Whirlwind). The last U.S. Army Chickasaw wasn't
retired until the 1980s.
In 1971, Aviation Specialties
introduced the S-55T, an S-55 powered by an Garret
TSE331. About 40 aircraft were converted and sold by Helitec
Corp.
