[Code of Federal Regulations]

[Title 14, Volume 1]

[Revised as of January 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 14CFR27.339]



[Page 578]

 

                     TITLE 14--AERONAUTICS AND SPACE

 

CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION

 

PART 27_AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT--Table 

of Contents

 

                     Subpart C_Strength Requirements

 

Sec. 27.339  Resultant limit maneuvering loads.



    The loads resulting from the application of limit maneuvering load 

factors are assumed to act at the center of each rotor hub and at each 

auxiliary lifting surface, and to act in directions, and with 

distributions of load among the rotors and auxiliary lifting surfaces, 

so as to represent each critical maneuvering condition, including power-

on and power-off flight with the maximum design rotor tip speed ratio. 

The rotor tip speed ratio is the ratio of the rotorcraft flight velocity 

component in the plane of the rotor disc to the rotational tip speed of 

the rotor blades, and is expressed as follows:

[GRAPHIC] [TIFF OMITTED] TC28SE91.083



where--



V= The airspeed along flight path (f.p.s.);

a= The angle between the projection, in the plane of symmetry, of the 

axis of no feathering and a line perpendicular to the flight path 

(radians, positive when axis is pointing aft);

omega= The angular velocity of rotor (radians per second); and

R= The rotor radius (ft).



[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as amended by Amdt. 27-11, 

41 FR 55469, Dec. 20, 1976]