From 65438 to 0945, Frank Biaseki designed a tandem twin-rotor search and rescue helicopter for the US Navy, which was nicknamed "Flying Banana" because of its slender and curved figure. This unique "banana" uses canvas to cover the body and Pratt &; Whitney R- 1840 AN- 1 piston engine. Mainly equipped with navy and coast guard. 1June, 948, Biaseki's design once again won the interest of the navy, and the new PV- 17 was photographed. After the navy tested five prototypes, it became the navy's HRP-2 search and rescue helicopter. Different from HRP- 1, HRP-2 adopts an all-metal skin fuselage, with a wider cab and a wider view, and the rotor tip has been improved. The PD-22 developed on the basis of HRP-2 eventually developed into CH-2 1, but at this time Biaseqi Company has been merged by Boeing Company to become Boeing Vetrol, which specializes in developing rotorcraft.

CH-2 1 also served in the US Air Force, the French Navy, the Royal Canadian Air Force and the West German Air Force. Among them, the French used an armed CH-2 1 in Algeria, and installed machine guns and uncontrolled rockets on the door and landing gear skid. It is this modified product that marks the birth of armed helicopters.

CH-2 1B assault helicopter upgraded its engine to 1 0,425-axis horsepower engine on the basis of the prototype, and its maximum speed was also increased to 128 mph. It can carry 22 fully armed soldiers, or 12 stretchers and two medical staff when performing rescue tasks. CH-2 1B first appeared in Vietnam196165438+February, and was equipped with the 8th and 57th transport companies of the Army to support army operations. Ch-21b/ch-2/kloc Shawnee can be equipped with 7.62mm or 12.7mm machine guns. Some of them also installed retractable machine guns under their noses. An interesting model was also tested in the United States, a Shawnee with a hemispherical remote control turret of Boeing B-29 Superfortress under its nose.

The speed of CH-2 1 is relatively slow, and its cables and tubing are easily damaged by small-caliber weapons. There are even rumors in Vietnam that a CH-2 1C was shot down by a Vietnamese spear. Shawnee was called "Bao Ma" because of his outstanding performance in Vietnam. They served in Vietnam until 1964 was replaced by Huey UH- 1 Most of Shawnee in the army was replaced by CH-47 chinook in the following years.