ID-1207
DESIGN, FABRICATION AND TESTING OF THE
HELICOPTER TAIL ROTOR BLADE FROM COMPOSITE
LAMINATED MATERIALS
Bosko Rasuo
Aeronautical Department, Faculty of Mechanical Engineering,
University of Belgrade, 27 Marta 80, 11000 Belgrade, Yugoslavia
SUMMARY: In this paper the design, fabrication and analysis of behavior by full-scale ver-ification
testing for the tail rotor blade of composite laminated materials for a heavy transport helicopter is
given.
The verification test program for the tail rotor blade encompassed static and dynamic test-ing.
The static tests of the blade involved experimental evaluation of torsional and flexional blade stiffness
and its elastic axis position. Dynamic tests involved testing of vibratory charac- teristics and testing of
blade fatigue characteristic. In structural vibration tests natural frequen-cy, vibration modes and
damping ratio for the structure were measured. The fatigue analysis of the structure of blade root
section was performed after fatigue test cycles for detection of laminate separation, tolerance and
distortion of crossections of structure.
KEYWORDS: Design, Fabrication, Verification Full-Scale Testing, Helicopter Tail Rotor Blade,
Composite Laminated Materials.
INTRODUCTION
In general, high-performance composites exhibit high strength and stiffness, low density, and good
resistance to fatigue and corrosion, properties that make them very well suited to many aircraft and
aerospace applications. The use of fiber-reinforced composites in flight critical structures in
helicopters is growing rapidly. But, the introduction of composites has not been without problems.
These include development of entirely new design, fabrication, and qualification discipline, difficulty
in analyzing internal stresses, demonstrating this technology to certifying agencies, determination of
adequate test criteria, and quantifying environmental degradation [1,2].
The development and qualification of the helicopter components and system includes a heavy
emphasis on a full-scale test approach independent from the design process. In the case of fatigue-
loaded flight-critical components, a laboratory fatigue program is conducted, suppo- rted by static
and vibratory tests, stress surveys and coupon or subelement programs [3].
The importance of full-scale testing in the development (and/or redesign) process for fiber-
reinforced composite helicopter blades is discussed, and illustrated by means of an example drawn
from Aeronautical Department (Faculty of Mechanical Engineering, University of Belgrade)
experience in the use of composites in a wide variety of structural applications. The laboratory
investigations of the structural properties are conducted at Aeronautical Department on all flight-
critical dynamic components in order to determine structural adequacy in designing process [3].
In this paper the design, fabrication and analysis of behavior by full-scale verification testing for a
tail rotor blade of composite laminated materials for a heavy transport heavy transport helicopter is
given (see Figures 1 and 2).
Fig. 1: The heavy transport helicopter.
