Main Rotor

Question 1

How many blades and what type of rotor system?

Answer 1

4 bladed fully articulated system

Question 2

Describe the MR blades composition

Answer 2

4 asymmetrical composite blades

• asymmetrical to optimize rotor efficiency
• dynamically balanced, interchangeable
• fiberglass/epoxy skin and spar
• Nomex honeycomb core
• nickel plated stainless steel leading edge strip
• coated with conductive pain to protect against lightning strikes and static charges
• tip weights added to increase inertia for better auto characteristics

Question 3

Describe the MR System and how aerodynamics are accomplished

Answer 3

4 Bladed fully articulated rotor system, 413 RPM @ 100% Nr/Np

Soft in plane, flex beam glass/epoxy composite yoke and hub

• acts as flapping flexure through “virtual” hinge in yoke
• flapping and droop stops protect/limit from excessive flapping
• cyclic centering system helps reduce mast stress while running, WOG

Elastomeric technology for the

• Feathering Bearing
• Lead/Lag Dampers

Aluminum: hub plate, pitch horns and spindles for strength and reduced weight

Question 4

Describe how flapping is accomplished

Answer 4

Through the soft in plane, flex beam glass/epoxy type yoke and hub
- acts as “virtual” flapping hinge through flapping flexure

Question 5

How is feathering accomplished?

Answer 5

Through elastomeric bearings

Question 6

How are lead/lag forces compensated for?

Answer 6

Through elastomeric dampers

Question 7

Diameter

Answer 7

35 feet

Question 8

Chord

Answer 8

10.75 inches

Question 9

Blade twist

Answer 9

• 13 degrees

Question 10

Approximate weight

Answer 10

~ 58 lbs

Question 11

RPM

Answer 11

413 RPM @ 100% Nr/Np

Question 12

Ratio

Answer 12

15.29:1 Reducing Ratio

Question 13

Describe the Frahm Damper

Answer 13

Dampens the 4 per rev vibrations from the main rotor and hub

A formed steel block is held in position by 8 heavy gauge springs
- Floats independent of upper and lower housing

As MR encounter turbulence, steel block vibrates at similar frequencies
Cancels vibrations prior to their descent into MR shaft and fuselage

Question 14

Describe the MR system cover

Answer 14

Convex fiberglass cover on top of the Frahm

• aerodynamic shaped for drag and noise reduction
• protects Frahm assembly mechanism from environmental factors

Question 15

When can the MR brake be used

Answer 15

Ground use only with Nr below 40%