CSP
−
902RFM207E
−
1
ROTORCRAFT FLIGHT MANUAL
MD900 (902 Configuration with PW 207E)
Systems Description
Original
7
−
8
Reissue 2
7
−
5.
MAIN ROTOR SYSTEM
The main rotor is a five-bladed, fully articulated hingeless flexbeam system. The
rotor diameter is 33.83 ft (10.34 m) with a blade chord of 10 in (25 cm). At its nominal
100 percent rotational speed (N
R
), the rotor runs at 392 rpm (695 feet/second tip
speed).
The flexbeam is primarily a unidirectional fiberglass/epoxy, y-shaped member that
connects the blade to the rotor hub, and twists and bends to accommodate the blade
motions, resisting centrifugal force while transmitting drive torque to the blade.
The five flexbeams attach to the hub by five bolts.
The pitchcase is a hollow, elliptically shaped graphite/epoxy tube that surrounds
the flexbeam and is attached to both the flexbeam and the blade at its outboard
end by a pair of expandable-bushing bolts. The pitchcase provides flapwise, chord
wise, and torsional stiffness to the inboard end of the blade and serves to transmit
the feathering control motions to the blade. The pitchcase is attached to the hub
at its inboard end by the elastomeric snubber/damper that provides centering for
flapping and feathering motions, and by a combination spring/damper restraint
for chordwise motion to eliminate ground resonance. An elastomeric bumper is
bonded to the flexbeam halfway along its length to bear against the inside of the
pitchcase and restrict a flexbeam bending oscillation that would otherwise occur
during spin-up and shut-down of the rotor.
Summary of Contents for MD900 Explorer
Page 4: ......
