Canadair CL-227 Sentinel

Lore & Background

The CL-227 Sentinel was designed in 1977, with the phase one prototype making its first flight on 25 August 1978. The larger production phase two vehicle first flew untethered on 14 December 1981. Following evaluation by NATO in March 1982, the UAV was made available to NATO allied clients in the early 1980s. The vehicle's distinctively unusual bulbous peanut shaped profile gave it its nickname of the flying peanut. Lift is provided by a set of coaxial rotors emanating from the waist of the system. The engine air is exhausted upwards to minimize the infrared signature. The blades are made of composite materials, as are all the external skin and legs, in an attempt to reduce the radar signature. The main structure is made mostly of aluminium. In the late 1990s, the CL-227 was replaced by an updated version, the CL-327, which was developed under Bombardier Aerospace after it acquired the assets of Canadair.

Reader's Guide

The CL-227 Sentinel represents an early effort in coaxial-rotor UAV design, with its unusual peanut shape becoming a distinctive visual hallmark. Its development spanned from the 1977 design through phase one and phase two prototypes, culminating in NATO evaluation in March 1982 and subsequent availability to allied clients. The UAV's design choices—coaxial rotors for lift, upward exhaust to reduce infrared signature, and composite materials for blades, skin, and legs to lower radar signature—reflect a focus on survivability and stealth for its era. The main aluminium structure provided a balance of strength and weight. The CL-227's legacy includes its replacement in the late 1990s by the CL-327 Guardian, an upgraded version produced by Bombardier Aerospace after it acquired Canadair. The Sentinel thus marks a transitional point in Canadian UAV development, bridging early experimental work with a more advanced production successor.

Did You Know?

• The CL-227 Sentinel was nicknamed the 'flying peanut' due to its bulbous peanut-shaped profile.
• Its coaxial rotors emanate from the waist of the system.
• The CL-227 was replaced in the late 1990s by the CL-327 Guardian.