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 (dog) to owe more to molosser than to spitz ancestry. The Chinook is an affectionate and playful family companion with a special devotion toward children. It is a willing worker who is eager to please and enthusiastic to learn. The Chinook is highly trainable, adaptable, and versatile in his abilities. Gregarious with other dogs, the Chinook works well in teams and within family packs. The Chinook is a dignified dog; some may be reserved with strangers but should never appear shy or aggressive. Health issues include normal hereditary problems such as epilepsy, hip dysplasia, and atopy. Also common is cryptorchidism, which