Concept
Although the concept took over three years to refine, the NOTAR system is simple in theory and works to provide some directional control using the Coandă effect. A variable pitch fan is enclosed in the aft fuselage section immediately forward of the tail boom and driven by the main rotor transmission. This fan forces low pressure air through two slots on the right side of the tailboom, causing the downwash from the main rotor to hug the tailboom, producing lift, and thus a measure of directional control. This is augmented by a direct jet thruster and vertical stabilisers.
Benefits of the NOTAR system include increased safety (the tail rotor being vulnerable), and greatly reduced external noise. NOTAR-equipped helicopters are among the quietest certified helicopters.
-
1 Air intake 2 Variable pitch fan 3 Tail boom with Coandă Slots 4 Vertical stabilizers 5 Direct jet thruster 6 Downwash 7 Circulation control tailboom cross-section 8 Anti-torque lift
-
Diagram showing the movement of air through the NOTAR system.
-
MD 900
-
Aerotécnica AC-14, Ducted exhaust and rudders detail
Read more about this topic: NOTAR
Famous quotes containing the word concept:
“The new concept of the child as equal and the new integration of children into adult life has helped bring about a gradual but certain erosion of these boundaries that once separated the world of children from the word of adults, boundaries that allowed adults to treat children differently than they treated other adults because they understood that children are different.”
—Marie Winn (20th century)
“Behind the concept of woman’s strangeness is the idea that a woman may do anything: she is below society, not bound by its law, unpredictable; an attribute given to every member of the league of the unfortunate.”
—Christina Stead (1902–1983)
“There is a concept that is the corrupter and destroyer of all others. I speak not of Evil, whose limited empire is that of ethics; I speak of the infinite.”
—Jorge Luis Borges (1899–1986)