Already for many decades the Chinook is the heavy-lift helicopter for many air forces around the world. Nowadays, the third major version is being built. Many of these are in fact rebuilt versions of earlier model, during which the airframe is completely stripped. It started its life at the end of the 1950s as the Vertol V-114, as an enlarged version of the V-107 that became the CH-46 Sea Knight. The US Army then gave it designation (Y)HC-1B, becoming CH-47A in 1962, with popular name Chinook.

The Chinook is a tandem helicopter with two three blade main rotors on top of pylons on top of the front and rear of the fuselage. The rear pylon is much larger and slightly higher than the front one. The rotors are powered by two turboshaft engines attached to the top of the rear fuselage, next to the rear pylon. To keep the fuselage free for cargo as much as possible, the Chinook has large sponsons along the lower sides of the fuselage. The four legged main gear is attached to these sponsons, the front ones about a third from the nose, the rear ones close to the ends of the sponsons, where the rear fuselage slopes up with a loading ramp. 

The different versions of Chinook can be distinguished by looking at (amongst others)

• the size and number of cabin windows
• the shape of the rear pylon
• the number of wheels on the rear main landing gears
• the presence of the long refuelling probe extending forward from the right sponson
• the shape of the sponsons along the side of the lower fuselage
• the presence of machine guns and/or rocket launchers at the side of the fuselage, behind the cockpit

More details will follow later.