CHARACTERISTICS OF THE TH-67 OPERATOR’S SUPPLEMENT
1. Define the term WARNING.
An operating procedure, practice, etc., which if not correctly followed could result in personal injury or loss of life.
2. Define the term CAUTION.
An operating procedure, practice, etc., which if not strictly observed could result in damage to or destruction of equipment.
3. Define the term NOTE.
An operating procedure, condition, etc., which is essential to highlight.
4. Define the term SHALL.
A mandatory procedure.
5. Define the turn SHOULD.
Recommended or preferred, not mandatory.
6. Define the terms MAY or NEED NOT.
An optional procedure.
7. Define the procedural term WILL.
Indicate futurity (in the future).
FORWARD SECTION
1. The three sections of the TH-67 fuselage are the ______, ______, and the ______Section.
Forward, intermediate, tailboom
2. The VFR & A+ configuration have one pitot tube that provides ______air to the airspeed indicator and two vents that provide ______air to the static instruments.
Impact (ram), static
3. The IFR configuration has ______pitot/static systems.
Two, independent
4. The TH-67 ______light, located on the aircraft nose provides a 450-watt lamp in an extendible and slew able mount.
Search
5. The TH-67 ______light located on the aircraft nose provides a 250-watt lamp in a fixed mount.
Landing
6. How many switches are used to control the search light in the NVG mode on the A+ configuration?
Three switches; one to select the IR light, one to turn the light on, and one to slew the search light to the desired position.
INTERMEDIATE SECTION
1. What does the term semi-monocoque mean?
The aircraft skin provides some of the structural strength.
2. The TH-67 intermediate section uses a ______type of construction.
Semi-monocoque
3. Which section of the aircraft contains the engine?
The intermediate section.
TAIL BOOM
1. The TH-67 tailboom section uses ______type of construction.
Fully-monocoque
2. State the purpose of the horizontal stabilizer.
The horizontal stabilizer maintains a desired aircraft attitude through the high end of the airspeed range. The metal strip at its leading edge provides for autorotational stability.
3. State the purpose of the vertical fin.
The vertical fin, being displaced (canted) 5 ½ degrees to the right, reduces the tail rotor thrust requirements in the forward flight.
4. At what airspeed is the tail rotor fully off-loaded in forward flight?
Between 100 and 110 knots.
ENGINE LIMITATIONS
1. The nomenclature of the TH-67 power plant is the model ______.
250-C20J
2. State the maximum torque available (MAX TQ AVAIL).
100% TQ for five minutes maximum.
3. State the maximum continuous power (TQ AVAIL CONT) of the TH-67 power plant.
85% TQ (270 SHP) no time limit.
4. Can the maximum transient power setting (110% TQ) be used intentionally?
No, intentional use is prohibited.
ROTOR SYSTEMS
1. State the diameter of the TH-67 main motor.
Main rotor diameter is 33’ 4”.
2. What type of airfoil is the main rotor blade?
An asymmetrical airfoil.
3. How many degrees of twist are there in the main rotor blade?
A negative 10 degrees.
4. State the tail rotor diameter.
Tail rotor diameter is 5’5”.
5. How many degrees of pitch are in the tail rotor with full left pedal applied?
23 degrees.
AIRCRAFT LIMITATIONS
1. State the TH-67 VNE.
130 knots.
2. State the maximum airspeed limitation with 85- 100% TQ (torque) applied.
80 knots (speeds above 80 knots with more than 85% TQ applied causes the rotor system to wobble).
3. State the minimum rate of descent airspeed in autorotation.
52 knots @ 394 RPM (100% rotor RPM)
4. State the maximum glide distance airspeed in autorotation.
69 knots @ 394 RPM (100% rotor RPM)
5. State the minimum crew restrictions VFR and IFR.
VFR minimum 1 pilot, IFR minimum 2 pilots (IMC).
6. State the limitations concerning fuel types.
JP4 (Jet B) may be used in all temperature ranges. Alternate—JP5, Jet A and JetA1 unusable at temperatures colder than -25ºF (-32ºC). Minimum pressure of 8 psi required at temperatures of 0ºF (-17.8ºC) to -25ºF (-32ºC). Minimum pressure of 4 psi required at temperatures warmer than 0ºF (17.8ºC).
7. State the fuel capacity of the TH-67 fuel cell.
84.1 US gallons total; 82.6 US gallons usable.
8. Why must the engine oil system be drained and refilled if transmission and engine oils are intermixed?
To prevent damage to the engine oil seals.
CONVENTIONAL HELICOPTER FLIGHT CONTROL SYSTEM
1. In a conventional helicopter, what are the three basic flight controls that are used to maneuver the aircraft?
The cyclic, collective and tail rotor (anti-torque) pedals.
2. In a conventional helicopter, what flight control directs the total lift/thrust of the main rotor system?
The cyclic is used to direct the total lift/thrust of the main rotor system in flight.
3. Which conventional helicopter flight control will input a pitch change to all main rotor blades simultaneously regardless of the blades position?
The collective stick applies input to all blades simultaneously.
4. An upward movement of the collective control increases the pitch angle in each main rotor blade thereby increasing the ______of the main rotor disc.
Lift/thrust
5. In a conventional helicopter, the rotation of the main rotor induces a force known as torque. Describe the effect that this force has on the helicopter fuselage.
The torque force will cause the fuselage of the aircraft to rotate in the opposite direction of the main rotor rotation.
6. State the primary purpose of the tail rotor system in a conventional helicopter.
To counteract the torque effect of the main rotor.
7. The ______controls will provide directional control (heading) of the aircraft during hovering operations, as well as trimming the fuselage of the helicopter at higher speeds.
Tail rotor.
TH-67 CYCLIC CONTROL SYSTEM
1. Cyclic control inputs (for/aft and lateral) are considered independent up to the ______from there on up to the non-rotating swashplate they are considered ______.
Intermixing bellcrank, coordinated
2. In the VFR configuration, what happens to the pilot’s cyclic stick when left unattended if the copilot’s cyclic is removed?
The reduced load on the balance spring will cause the pilot’s cyclic stick to creep aft slightly.
3. Where is the cyclic friction knob located?
Left of the base of the pilot’s cyclic stick.
4. How much preload is on the cyclic system with the aircraft running and hydraulics on?
One half to one pound preload.
5. Which aircraft configuration has the force trim system?
The IFR configuration only.
TH-67 COLLECTIVE CONTROL SYSTEM
1. What switches are located on the pilot’s collective stick control head?
Search light switches, landing light, governor RPM increase/decrease, and starter button.
2. Where is the collective friction located?
It is located to the left of the pilot’s collective stick base.
3. What switches are located on the co-pilot’s collective control head?
There is no co-pilot’s collective control head.
4. What amount of collective control preload is built into the collective flight control system?
A 3 to 5 pound preload.
5. Which collective control stick is removable and why?
The co-pilot’s collective control stick is removable in case a non-rated passenger is flown in the co-pilot’s seat.
TH-67 ANTI-TORQUE CONTROL SYSTEM
1. Which direction can the tail rotor pedals be adjusted?
The pedals can be adjusted fore and aft.
2. What changes the pitch (angle-of-attack) in the tail rotor through the lever assembly?
The pitch change links.
3. What is the preload on the tail rotor system?
The preload is 4 to 5 pounds.
4. Does the tail rotor system have hydraulic assist?
The tail rotor system does not have hydraulics.
TH-67 HYDRAULIC SYSTEM
1. The TH-67 flight control system can best be described as ______with hydraulic assist.
Direct mechanical linkage
2. The purpose of the hydraulic servo actuator installed to the cyclic and collective controls is to convert ______into ______.
Hydraulic (fluid) under pressure, useful mechanical work.
3. The Th-67 hydraulic pump is a constant ______, ______delivery system component providing 600 +/- 25 PSI, and ______GPM flow rate.
Pressure, variable, 1.9
4. The TH-67 hydraulic reservoir outer case is finned to provide cooling. In addition, cooling air from the ______is directed to the transmission oil cooler where some air is scavenged and directed to the ______.
Oil cooler fan, aft base of the hydraulic reservoir, (one fan cools the engine, transmission and hydraulic systems).
5. On the TH-67, a red “pop-up” indicator installed on the pressure line filter on the line from the pump to the hydraulic solenoid valve will “pop-up” when the pressure differential reached 70 PSID. This is an indication to the pilot that _____.
The filter is clogging—failure of the hydraulic assist will progressively occur.
6. The purpose of the differential relief valve is to reduce ______when rotor loads are increased due to high “G” maneuvering or flight into turbulence.
Pressure build up.
7. Why is the hydraulic solenoid valve said to be a fail-safe switch?
The hydraulic solenoid valve is spring loaded to the open position thus requiring electrical power to close. Accordingly, following total electrical failure with the hydraulic control switch in the ON position, Hydraulic assistance to the flight controls will remain. During a total electrical failure with the hydraulic control switch in the OFF position (no hydraulic assist to the flight controls), electrical power would be removed from the solenoid switch thus allowing it to “spring” open restoring hydraulic assistance to the flight controls. This is known as a “fail-safe” switch. This prevents compound failures.
SWASHPLATE AND SUPPORT ASSEMBLY
1. What will an upward movement of the collective stick do to the swash plates?
An upward movement will cause the swash plates to move upward which will change the pitch in both blades simultaneously.
2. What will cyclic input do to the swash plate assembly?
Cyclic input causes the non-rotating swash plate to tilt about an uni-ball support assembly in the direction the cyclic stick is pushed.
3. With regard to cyclic input, does the blades position in the plane of rotation matter?
Yes, the desired input does not occur until the blade is positioned exactly 90º earlier in the plane of rotation (phase lag).
4. What drives the rotating swash plate?
The connection of the collar set and idler lever/link assembly to the rotating swash plate.
5. What is another name for the collar set and idler/link assembly?
It is also called a drag link assembly.
6. What connects the rotating swash plate to the pitch change horn?
The pitch change tubes.
MAIN ROTOR HUB ASSEMBLY
1. What type of rotor system is used on the TH-67 helicopter?
A semi-rigid, under slung rotor system.
2. How is the rotor system attached to the mast?
The rotor system is attached to the mast by a splined trunnion.
3. What is the definition of a trunnion?
A component that allows rotation and tilt.
4. What is the purpose of the yoke?
To support the main rotor system and serves as the pitch change axis.
5. How is the trunnion attached to the yoke?
The trunnion is attached to the yoke by pillow blocks.
6. What distributes the centrifugal load from the blade grip to the yoke?
Tension torsion straps distribute the centrifugal load from the blade grip to the yoke.
7. What kind of balancing requires lead weights to be added to the blade retention bolt?
Spanwise (root to tip) balancing requires lead weights to be added to the blade retention bolts.
MAIN ROTOR BLADE ASSEMBLY
1. What structural members make up the main rotor blade?
The aluminum spar, the spar closure, and the trailing edge.
2. What is added at the factory to preserve favorable aerodynamic characteristics?
Weights are added at the factory at the time of manufacturing to control the undesirable twisting associated with asymmetrical airfoils and to preserve favorable aerodynamic characteristics.
3. Why does the main rotor blade have a negative 10º twist?
The negative twist is designed to equalize lift along the blade span (length).
4. The “droop snoot” is known for what aerodynamic characteristics?
The “droop snoot” design is noted for a wide thrust margin for maneuverability and high efficiency during hovering.
5. How many trim-tabs are there on the main rotor blade?
Two trim-tabs are placed on the trailing edge of the main rotor blade; one for adjusting the inner blade track and a second trim-tab is used to adjust the outer portion of the blade’s track.
6. What are doublers used for on the main rotor blade?
They are applied at the blade root to sustain the shearing force caused by the centrifugal force occurring at the blade retention bolt.
FLAP RESTRAINT KIT
1. What is the purpose of the flap restraint kit?
It’s purpose is to limit flapping during startup and shutdown.
2. At what RPM is flapping limited to 6º maximum?
It is limited to 6º maximum at 25% N2 RPM and below.
3. At what RPM is the flapping angle no longer limited?
The flapping angle is no longer limited above 31% N2 RPM.
TH-67 TAIL ROTOR AND HUB ASSEMBLY
1. How is the tail rotor assembly mounted to the tail rotor output shaft?
It is mounted to the tail rotor output shaft by a splined trunnion.
2. How does the tail rotor system compensate for dissymmetry of lift?
The tail rotor assembly compensates for dissymmetry of lift through the delta hinge by allowing the blade to feather as it flaps.
3. What are the washers on the blade bolts used for?
The washers on the blade bolts used for spanwise balancing.
4. What are the rectangular weights and washers on one end of the trunnion used for?
The rectangular weights and washers on the trunnion are used for chordwise balance.
5. What are the nut, bolt and washer(s) used for on the dynamic balance wheel?
The nut, bolt and washer(s) on the dynamic balance wheel are used to eliminate high frequency vibrations and to assist in spanwise and chordwise balance.
6. Where are the weights that are added at the factory located?
The factory added weights are located on the inboard trailing edge and at the blade tip.
7. What are the washers on the pitch horns used for?
The washers on the pitch horns are used as an aerodynamic balance to eliminate “pedal creep”.
8. How many degrees of pitch are there in the tail rotor with full left pedal applied?
With full left pedal applied there are 23º of pitch in the tail rotor.
MODEL 250-C20J TURBINE ENGINE
1. The TH-67 engine’s rated shaft horsepower is de-rated for ______.
Transmission compatibility.
2. The maximum torque available is ______for ______minutes.
100% TQ, 5
3. The continuous torque available is ______for ______minutes.
85% TQ, no time limit.
4. The statement that best describes the TH-67 engine is “Internal combustion gas turbine featuring a ______.
Free power turbine.
5. What are two advantages of a free turbine?
Reduced load for starting, and each turbine operates at optimum RPM capacity.
AIR FILTERING SYSTEM
1. The purpose of the Air Barrier Filter is to provide clean ______air to the engine.
Particle-free.
2. Will the engine air be filtered if the ENG ALT AIR switch is placed in the OPEN position?
No, when the air barrier filter is bypassed, unfiltered will be going into the engine.
3. What indication will the pilot receive when the air barrier filter is blocked/clogged?
The LOW INLET PRESSURE caution light illuminates.
C20J ENGINE COMPRESSOR SECTION
1. What are the four sections of the model 250-C20J turbine engine?
The compressor, power and accessory gearbox, turbine, and combustion.
2. What does the bleed air control valve do?
It aids in rapid engine acceleration and helps prevent compressor stalls.
3. What are the five customer bleed air ports on the diffuser scroll?
The engine Anti-ice valve, Bleed-air control valve, two Cabin heat ports, and PC air filter. (ABCCP)
4. What is the purpose of the cap on the rear diffuser vent and cap?
To increase air pressure on one side of two labyrinth seals as the compressor experiences wear.
5. The compressor consists of how many and what kind of compressor stages?
It consists of six axial stages and one centrifugal stage.
6. On a standard day (59ºF, 15ºC) the airs temperature increases to approximately ______ºF by the time it goes through the seventh stage of compression.
520º
7. What are the only items provided with anti-icing capability?
The front support hub and the seven inlet guide vanes.
8. Should the bleed-air control valve be opened or closed on preflight?
The bleed-air control valve SHALL be open on preflight or maintenance action is required.
COMBUSTION SECTION
1. When does the spark cease to exist in the combustion section of the engine?
When the starter button is released.
2. What is the temperature of the flame in the combustion section of the engine?
Approximately 3500ºF.
3. What is the melting point of titanium?
Approximately 2200ºF.
4. How much of the compressed air is used for combustion?