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
Billy Chinook in the Oregon Country. Chinook was an orphan and lived at the mission. In the summer of 1843, then-Lieutenant John C. Frémont and Kit Carson visited the present-day Bend, Oregon and The Dalles, Oregon areas. Chinook was 16 to 19 years old at the time and was recruited by Frémont as a guide. The Frémont expedition (Frémont's second) then explored central Oregon and the Klamath Basin, and further into present-day Nevada and California areas through July 1844. In 1845 Frémont traveled to Washington, D.C. with Chinook. While there, Frémont awarded a medal to Chinook which bore the likeness of the