B206L3 Transmission and Drivetrain

Question 1

Freewheeling Assembly

Answer 1

Enables autorotation by decoupling from engine. Contains a chip detector. Lubricated by transmission oil system.

Question 2

Main Drive Shaft

Answer 2

Flexible couplings accommodate movement between the transmission and freewheeling assembly.

Question 3

Transmission

Answer 3

Incorporates nodal beam suspension system.

2 stage RPM reduction of about 15:1

Question 4

Transmission oil system

Answer 4

Lubrication provided by: Oil pump, pressure regulating valve, oil cooler, filter element, 2 spray jets.

Question 5

Transmission Accessory Components

Answer 5

Oil pump
Rotor tach/gen
Hydraulic pump

Question 6

Transmission chip detectors

Answer 6

3 chip detectors.

2 on transmission (one top one bottom), 1 on freewheeling unit.

Question 7

Transmission oil filter

Answer 7

Located on aft side of transmission.
Contains bypass valve with LRB indicator.
TRANS OIL TEMP sensor bulb is located on filter housing.

Question 8

Oil cooler

Answer 8

2 cores, 1 for transmission, 1 for engine oil cooling. Oil cooler blower is connected directly to short shaft going to the TR

Question 9

Transmission mounts

Answer 9

Nodal beam and flexure strap. Elastomeric bearings and bushings.

Question 10

Main Rotor Hub and Blade

Answer 10

• Semirigid, underslung hub.
• Splined Trunnion attaches hub to mast and allows for flapping.
• Pillow block housing contains roller bearings for flapping.
• “TT” strap: Tansion torsion strap connects grip and yoke. The flexibility of the strap allows for feathering.
• Grip assembly attaches to blade root via blade retention bolt.
• MR blades have -11 deg twist and droop snoot airfoil.
• Droop stops limit flapping during low RPM but allow it at higher RPMs.

Question 11

Tail Rotor Driveshaft

Answer 11

5 segments connected by Thomas couplings and supported by hangar bearings (DESIGN WEAK POINTS)