Helicopter rotor of gravity fore-aft. However, it requires the expense of two large rotors rather than the more common one large main rotor and a much smaller tail rotor. The Boeing CH-47 Chinook is the most common tandem rotor helicopter. Coaxial rotors are a pair of rotors mounted one above the other on the same shaft and turning in opposite directions. The advantage of the coaxial rotor is that, in forward flight, the lift provided by the advancing halves of each rotor compensates for the retreating half of the other, eliminating one of the key effects of dissymmetry of lift: retreating blade
Mil Moscow Helicopter Plant Series production facilities for Mil-designed helicopters include Rostvertol in Rostov-na-Donu, the Kazan Helicopter Production Association, and the Ulan-Ude Aviation Plant. Mil participates in the Euromil joint venture with Eurocopter. Mil was established in 1947 under the guidance of Mikhail Mil as the helicopter laboratory of the Central Aerohydrodynamic Institute in Zhukovsky, Moscow Oblast. The Mil Mi-1 became the first mass-produced Soviet helicopter. The Mi-8 helicopter, designed in the early 1960s, was a successful design in both military and civil applications, with over 12,000 units being produced. Mil merged with Kamov and Rostvertol to form Russian Helicopters in 2006. The Mil