Hughes TH-55 Osage

The Hughes TH-55 Osage was a light, training and utility helicopter in service with the US Army between 1964 and 1988. It was replaced by the TH-1A Iroquois. It was also used by almost every police department in the United States of America for search, security and monitoring duties. Hughes built almost 3,000 helicopters both for military and civil usage.

The prototype of the TH-55 Osage, Model 269, first took to the air on October 2, 1956. It would take the helicopter almost four years to enter the mass production phase in 1960, with the first variant being the Model 269A, which the US Army would designate the TH-55 Osage. The main civil aviation variant was the Hughes Model 300 (269B), which was a three-seater chopper. The Model 300C was the most widely produced version, with more than 1,000 units.

In military service, several countries adopted the Hughes TH-55 Osage, mainly for pilot training. It was supplied to Spain, Sweden, Japan, Colombia, Nigeria, and Algeria. It would also be produced by the firm Schweizer, which developed the new TH-300C trainer version.

Technical Description

The TH-55 Osage was a light, vertical take-off and landing, and hover aircraft, which is propelled by two bladed rotors. The main rotor was fitted with three blades of metal construction, with aluminum core spar. The tail rotor was of the teetering type, with just two blades, freely pivoted as one union; these blades consisted of steel spar, with glass-fiber skin.

The helicopter featured a simple, rod-like boom, which was made of alloy metal. It had a ventral, triangular fin, while the extreme end was fitted with an upper oblique fin. The cabin of the TH-55 could accommodate three crew members, sitting side by side, with an instructor and two students. It consisted of a metal frame with Plexiglass, which gave the pilot and excellent view. The TH-55A version was powered by one HIO-360-D1A piston engine, which delivered 190 horsepower.

Specification

Type: light trainer and utility helicopter

Rotor Diameter: 8.18 m (26 feet, 10 inches)

Fuselage Length: 9.40 m (30 feet, 10 inches)

Height: 2.66 m (8 feet, 9 inches)

Weight: 474 kg (1,050 lb)-empty

Power Plant: one 190-HP, HIO-360-D1A piston engine.

Maximum Speed: 153 km/h (95 mph)

Range: 360 km (224 miles)

Service Ceiling: 3,110 m (10,200 feet)

Above, the civil version of the TH-55, the Model 300.

The Osage in the US Army service.

Above, the helicopter as a utility one in service with Los Angeles, CA, police department. It is fitted with search light, a siren, and a warning light.