9Know Your Helicopters is a pocket-sized book detailing 44 types of helicopters most commonly seen in service today from the smallest Robinson to the biggest Mil, including Bells, Boeings, Sikorskys and many more. A photograph of each machine is included.Tom Hargreave served 18 years in the British Army as an Army Air Corps pilot. In this time he accumulated 2,500 hours of flight time across a variety of helicopter types including the Gazelle, Lynx, Agusta 109 and the Apache.