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
Chinook Jargon Chinook words and phrases in her writing. In Oregon, Chinook Jargon was widely used by Natives, trappers, traders, employees of the Hudson's Bay Company, missionaries, and pioneers who came across the Oregon Trail from the 1830s-1870s. In Portland's first half century (1840s-1890s) there were frequent trade interactions between pioneers and Native Americans. After about 1900, when such daily interactions were less frequent, Jargon was spoken among pioneer families to prove how early they arrived out west. Many Oregonians used Jargon in casual conversation—to add humor, whimsy or emphasis and to exhibit deep knowledge of Oregon's history. Though traditions of speaking