TH-1H Transmission [Systems]

What is the purpose of the transmission system?

Changes engine RPM to usable RPM (20.4:1) gear reduction

Changes angle of drive 90 degrees

Mounts and drives accessories

Allows for autorotation through the use of the free-wheeling unit (sprag clutch)

The transmission system consists of what 5 cases?

1. Top Case

2. Planetary Ring Gear Case

3. Main Case

4. Support

5. Sump Case

What does the top case contain?

Mast mounting

What does the planetary ring gear case contain?

Planetary reduction gearing

What does the main case contain?

Input quill with free-wheeling unit location, accessory mount pads

What does the support case do?

Mounting within the airframe

What does the sump case contain?

Oil sump

T/R output shaft

Accessory mounting for hydraulic pump

Rotor tach generator

What is the warning associated with the rotor brake?

WARNING: Applying the rotor brake above 40% Nr will increase the tendency for the aircraft to spin on smooth surfaces.

How many isolation mounts are there?

5 mounts

What do friction dampers do and where are they attached?

Aids in restraining pylon rock and is attached to two aft outboard mounts?

What does the lift link do and where is it attached to?

Lifts the airframe when pitch is applied to the main rotor, and it is attached to the center of the transmission and to the airframe lift beam.

What does the main driveshaft do and where is it located?

Transmits power to the transmission and is located between the engine output coupling and transmission input drive quill.

What do the flexible plates do and where is it located?

Maintains alignment between flexibly mounted transmission and rigidly mounted engine and is located at the end of each drive shaft.

What is the purpose of the freewheeling unit?

Allows for autorotation

The oil system has a thermal bypass valve which causes the oil to bypass the cooler when the oil is below ______ degrees C

54.4 degrees C

What does the thermo-switch do?

Controls XMSN OIL HOT light

When does the XMSN OIL HOT light turn on?

Above 110 degrees C

What does the pressure switch do?

Controls the XSMN OIL PRESSURE caution light

When does the XSMN OIL PRESSURE caution light illuminate?

30 PSI +- 3 PSI

How many chip detectors does the transmission system have?

5 chip detectors

There are ____ chip detectors in the main transmission and ____ in each tail rotor gearbox.

3 chip detectors in main and 1 in each tail rotor gearbox (2 total).

What 3 positions does the chip detector switch have?

XSMN

BOTH

TAIL ROTOR

How many driveshaft sections are there?

6 drive shaft sections

The 90-degree gearbox has what two functions?

Changes the angle of drive and reduces the RPM 2.6:1

The 42-degree gearbox has what function?

Changes the angle of drive.

What do hanger bearings do?

Provides a means of flexibility attaching the drive shaft sections together.

What 4 accessories are driven by the transmission?

Main generator

Hydraulic pump

Rotor tach

Rotor brake

What do the split V clamps do?

Secure the driveshaft to engine and transmission

The thermal bypass opens at _____ degrees C for the transmission oil?

54.4 degrees C

Top case and planetary case do not have _____ capability but the sump case does.

Fuzz burn

90 degree gearbox reduces RPM to...

1654 RPM

T/R driveshaft operates at what RPM?

4,301 RPM

What do hangar bearings do?

Provides a means of flexibility attaching the driveshaft sections together