Present day requirements on a limited noise factor were taken into consideration in the design and construction of the Il-62 aircraft. This was accomplished by using turbofan engines with a comparatively low exhaust velocity of the jet stream and special piloting techniques during takeoff. The NK-8 turbofan engines mounted on the Il-62 have a by-pass ratio approaching m equals 1. Therefore, under takeoff conditions of operation the noise from the principle sources is just about the same. To decrease the noise produced in the immediate vicinity, the takeoff of the Il-62 is performed in the following manner: (1) After liftoff, at a height of 5 to 8 m, the landing gear is retracted. Simultaneously the aircraft accelerates and climbs. The speed is maintained up to H equals 150 m. (2) During acceleration above 150 m, the flaps are retracted from 30 to 15 degrees. The climb to an altitude of 800 m is accomplished with 15 degrees flaps and at a constant speed of 310 to 345 km/hr, depending upon the take-off weight of the aircraft. (3) At an altitude of 800 m in the process of acceleration, the flaps are fully retracted in such a manner that this operation is completed at the moment the aircraft attains a speed of 400 km/hr. (Author)
Farther, Higher and Quieter
1969
9 pages
Report
No indication
English
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