The CH-1 had a single, two-bladed main rotor, and a front-mounted reciprocating engine which gave the aircraft a stable center of gravity (CG).

Originally certified as a two-place helicopter, stability problems at higher gross weights required additional engineering solutions.

Reworking the stabilizer permitted the addition of a second row of seating, and the four-place ship, designated the CH-1A, was certificated on 28 February 1956.

The aircraft incorporated a unique L-section hinges to attach the main rotor blades to the hub in place of more conventional pitch change bearings.

It was a low profile streamlined aircraft-style body, featuring the engine in front and cabin seating behind the powerplant.

The prototype CH-1 was originally equipped with a supercharged Continental FSO-470 six-cylinder engine, producing 260 hp (190 kW) at 3,200 rpm.

The CH-1A was the first helicopter to land on Pikes Peak, at an altitude of 14,110 feet (4,300 m) on 15 September 1955,[2] it had a higher cruise speed than comparable machines, and a CH-1B, modified with an FSO-526-2X engine, set an official FAI world altitude record for helicopters of 29,777 feet[note 1] on December 28, 1957, while being piloted by Army Captain James E.

[4] The CH-1C was the first helicopter to receive instrument flight rules certification by the Federal Aviation Administration.

The Army Aviation Museum at Fort Novosel, Alabama has a YH-41 Seneca prototype (serial number 56-4244) as a part of its collection, although it is not currently on display.