What are the datum points for the fuselage section of S61N?
- Vertical: Water line = 79' at keel
- Lateral - too narrow to be of consequence
- Longitudinal: 32" in front of nose to accommodate original design incorporating nose mounted pitot mast
How many jack points are there and where are they located?
- 1 at tail wheel
- 1 on each side of hull, at sponson spacing strut
- 1 under each oleo strut
What is overall length of S61N longbody?
What is height at mast of S61N longbody?
What is the height at tail rotor of S61N longbody?
What is the rotor diameter of S61N longbody?
What is the aircraft width of S61N longbody?
- external: 7'1"
- internal: 6'6"
- at wheel center: 14' with fixed gear equipped
What are the dimensions of the airstair door?
- 30' wide X 65.5" high
- 2'8" W X 5'6" H
What is the purpose of the horizontal stabilizer bar?
it is attached to the airframe with a negative 4 degree angle of incidence and is designed to become effective at approximately 40 kts. It provides the downward force on the fuselage to help keep the aircraft at a more level attitude at higher airspeeds.
How many compartments are there in the hull?
What is housed in the tail cone fuselage section of S61N longbody?
- Compass flux gate
- quadrants that converts TR cable inputs to TR control rod inputs
What is housed in the tail pylon fuselage section of the S61N longbody?
- Intermediate gearbox 44 degree angle
- 90 degree gearbox
- Tail Rotor
- Negative force gradient spring
- on top: white strobe light and red rotating beacon
How many windows are there?
- 10 on the left side and 8 on the right, 5th on the left is the emergency exit. normal windows are various sizes with pullout tabs
What type of engines does the S61N have installed on the aircraft?
GE CT58-140-2 engine, free turbines with output of 1500 SHP to the transmission input. The 10 stage gas generator produces approximately 4300 SHP of which 2850 or 2/3 is required to sustain engine operation
What type of de-icing does the engine have?
- 12 and 3 oclock struts de-iced with 10th stage bleed air
- 6 o'cock strut - #1 bearing scavenge oil
- 9 o'clock - heated with balance chamber air
What does the radial "pencil' shaft do and where is it located?
- it is through the 6 o'clock strut and drives:
- centrifugal fuel filter
- fuel pump
- fuel control
- engine oil pump/Ng tachometer
- Ng governor portion of the FCU
What does the compressor rear frame of the engine house?
- outer ring
- inner diffuser ring with 6 radial struts
- top strut provides oil for the #2 bearing
- bottom strut returns scavenge oil
- remaining 4 struts are structural and provide bleed air passage
- at the 2 o'clock position is the connection to the fuel control unit
- at the 10 oclock position is the external piping to fuel control for aspirator effect and for sensing T2 air
How long do stator vanes remain closed for?
5% Ng and then gradually open to full at 95% Ng. This ensures stall free operation
What rpm does the main drive shaft rotate at?
18966 rpm at 100%
What type of oil system does the engine have?
- dry sump system that is automatic:
- it is gravity fed from tank to a compound pump
- the oil tank capacity is 4.5 gallons, but normally serviced to 2.5 gallons
- delivered under pressure to engine bearings and accessory case for lubricating and cooling
- scavenge side of pump returns oil to the oil ring tank via a fuel/oil heat exchanger
- system incorporates bypasses for temperature and pressure
Describe the oil pump of the engine
- it is divided into 5 parts:
- one part provides pressurized oil for bearings
- 4 parts scavenge oil from engine sumps
- run by a shaft from the accessory section
- a check valve to prevent oil from flooding the engine when static (3-5 psi pump pressure opens it)
- 1 40 micron oil filter (water screen type) in the drive casing
- a spring loaded filter bypass with a differential pressure of 18 =/- 3 psi
- a spring loaded poppet type relief valve to bypass oil back to scavenge side of pump to protect against excessive pressure (70 +/-3 psi
How many engine chip monitoring systems are on the engine?
2 detectors on each engine: one on the accessory case and another one at the no. 5 bearing. the light stays on till power removed even if chips are washed away.
What is the purpose of the centrifugal fuel filter?
mounted on the front of the accessory gearbox, it spins at 4200 rpm at 100% Ng and throws heavier contaminants to the outside of the casing. This is cleaned every 150 hours
What type of pressure does the fuel pump produce?
0 - 995 psi, bu normal operation 210 - 795
What does the emergency speed lever do?
Directly controls the metering valve bypassing auto features of the FCU.
When is overspeed shutoff activated?
by the Nf governor at approximately 122% Nf and won't function without the flex shaft.
what pressure does the engine driven fuel pump operate at?
200 psi at idle to 1000 psi at 102% Ng
What does the 3D cam provide?
- topping 103.4%
- Idle 56 +/-3%
- maximum acceleration limit
- controls variable stator vane position
How many fuel nozzles are there?
- 8 primary (opens at 140 psi at start and idle)
- 8 secondary (open at 185 psi at high power settings)
- sensed by governor through flex shaft
- Nf tachometer is mounted on back of the FCU
- Nf governing range is 90-110%Nf
- No droop compensation
- Nf over-speed shuts down engine at 122% Nf. There is no reset in field & not operable if flex shaft fails
- If engine fluctuation at high power setting, possible lube of flex shaft may be required
When would you do topping checks on engine?
- every 450 hours
- after maintenance
- 20 degree C change
- stator vane adjustment
- fuel density change
- fuel pump change
- engine removal/change
What is the maximum allowable difference between engines during flat pitch check?
0.5% Nf difference
What are the 5 parameters that fuel control senses?
- Am: speed control lever position
- Ng: gas generator speed
- Nf: power turbine speed
- P3: compressor discharge pressure
- T2: compressor inlet temperature
What adjustments can be made at the fuel control?
- fuel density
- Bottoming (ground idle 56% +/- 3%)
- Throttle valve (start temperature)
When does the overspeed shutoff valve activate?
Closes at 122% Ng or 23,400 RPM
What are the components to the ignition system?
- starter button
- 2 igniters
- exciter box on the 3 oclock position of the compressor
- on/off/test switch on the overhead panel in the cockpit
- a start bleed valve (to relieve compressor back pressure, mounted on the bleed pot of the upper combustion casing
- a start fuel shut off valve the is opened by the start relay and cyclic buttons that control it
- master start switch
- speed selector lever
Describe the starter
Mounted on the compressor front frame, it is a DC motor with a spring actuated toothed engagement, ("dogs") and a bracket that mates to a like bracket on the front end of the compressor rotor shaft; a torque limiting clutch built into the starter prevents damage to the shaft on initial engagement and prevents overloading the starter. It is rated for 650 amps, but can withstand 1000 amps.
What happens when the starter relay is energized?
the starter motor is connected to the DC essential bus and spins the compressor by engaging the "dogs" which are gear teeth on the end of the bendix spring (just like a car starter)
What does the start bleed valve do?
as long as power is applied, the start bleed valve is held open by a holding circuit to dump 6.7% of compressor discharge air. This reduces the back pressure on the compressor rotor and reduces the possibility of compressor stall on start. It remains activated for 3-7 seconds after the start relay is energized, continuing to relieve back pressure to insure the engine is self sustaining.
What does the start fuel valve do?
it is opened by the start circuit and provides additional fuel for starting from the flow divider. The start fuel flow is controlled by the switch on either cyclic hand grip to interrupt the flow and control temperature
What do the two separate anti-ice systems to each engine provide?
- One protects the engine air inlet duct from icing and heats the engine oil tank mounting ring
- the other protects the starter fairing, inlet guide vanes, and portions of the engine front frame.
Since Engine anti-ice fails to the on position, what will the result be on affected engine should this fail?
- Approximately 2% Q power loss
- 5 degree increase in T5
Describe the engine torque indicating system.
The torque indicator indicates the amount of torque being applied to the main gear box by the engines. The application of torque from the engine to the input shaft of the main gear box actuates a valve that causes high pressure oil to react on a helical gear. This reaction causes components within a sensing chamber to seek a neutral position between the force of the oil and the applied torque. The shifting of these components results in metered oil pressure that is transmitted to the cockpit indicators and displayed as a percentage of torque. The torque pressure transmitters are mounted on the web of the transmission mounting area between waterlines 243 and 290
What is the gas generator tachometer rpm?
26,300 rpm which is equal to 100%
What is the RPM for Nf speed at 100%?
What is the 206q rule in regards to the engine?
When both engines are operating, the combined torques cannot exceed a total of 206Q (i.e. if one engine is producing 106Q then the amount that can be used on the other engine is 100Q
What are the Nf powerplant limitations as indicated on the gauge?
- Min: 91%
- precuationary: 91%-100%
- normal: 100%-106%
- precautionary: 106%-110%
- Maximum: 110%
What are the powerplant limitations for rotor speed Nr (power off) as indicated on the gauge?
- Minimum: 91%
- Transient: 91%-100%
- Normal: 100% - 111%
- Maximum: 111%
What are the powerplant limitations for rotor speed Nr (power on) as indicated on the gauge?
- Minimum: 91%
- transient: 91%-100%
- normal: 100%-106%
- Maximum: 110%
What are the powerplant limitations for T5 as indicated on the gauge?
- Normal: 300-660 deg C
- Precautionary: 660-758 deg C
- Max takeoff: 696 deg C
- Max 2.5 minutes: 758 deg C
What are the powerplant limitations for Ng as indicated on the gauge?
- Minimum: 53%
- Normal: 56%-100%
- Max takeoff: 100%
- Precautionary: 100% - 103.4%
- Maximum: 103.4%
- Maximum overspeed: 105% for 15 seconds
What are the transmission torque limits as indicated on the gauge?
- Normal: 0%-86.5%
- precautionary: 86.5%-103%
- Max dual engine: 103% (1250 SHP at 100% Nf)
- max single engine:
- - 123% (1500 SHP at 100% Nf) for 2.5 minutes
- - 115% (1400 SHP at 100% Nf) for 30 minutes
- - 150% for 20 seconds
What are the powerplant limitations for fuel pressure as indicated on the gauge?
- Minimum: 160 psi
- normal: 210-795 psi
- Precautionary: 795-995 psi
- maximum: 995 psi
What are the powerplant limitations for engine oil temperature as indicated on the gauge?
- Minimum: -54 deg C
- normal: 0-121 deg C
- Maximum: 121 deg C
What are the powerplant limitations for engine oil pressure as indicate on the gauge?
- Minimum: 8 psi
- Normal: 20-60 psi
- precautionary: 60-75 psi
- maximum: 75 psi
What does it mean when #1 or #2 engine oil pressure light illuminates?
engine oil pressure has dropped to below 8.5 psi in the respective engine
What does it mean when the #1 or #2 ENG CHIP light has illuminated on caution panel?
ferrous particles have been detected in the respective engine oil.
What does it mean when MAIN BATT OVTEMP or ALT BATT OVTEMP lights have illuminated on caution panel?
Main battery temperature or alternate battery temperature has reached 145 deg F +/- 5 deg F indicating a possible thermal runaway.
What does it mean when EXT PWR ON light is illuminated?
- AC/DC external power is plugged in
- the Ext power switch is on
- the power has been accepted by the aircraft electrical system
What does it mean when DC GEN MOTORIZED light is illuminated?
The DC Generator is motorized to drive the accessory section of the XMSN to pre-lube the XMSN and provide hydraulic pressure.
What does Category A mean?
This procedure requires that a single engine 150 fpm rate of climb capability at best rate of climb speed be maintained while at an altitude of 1000 feet above the takeoff surface with the engine operating at takeoff power. All engine configurations may be used when operating in this category
What does Category B mean?
This procedure requires a hover in ground effect capability at all altitudes and temperatures within the approved limitations. All engine configurations may be used when operating in this category.
Where is the CG datum located?
267.4 inches forward of the center line of the main rotor hub
What does supp 6 add to RFM?
It increases altitude for take off and landing to 12,000' DA, 14,000' DA enroute and class B. It is for the Carson composite blades and supercedes supp 15 & 16 in the listed areas.
What does supp 7 add to RFM?
Adds VNE for AFCS/Aux inop to 90 KIAS, mentions ISA+25 and more depending on ice equipment
What do supp 15 & supp 16 add to RFM?
- Supp 15: increases weights for Cat A to 20,500 lbs.
- Supp 16: Increases weight of Cat B to 22,000 lbs./8,000 on hook.
What does the empty weight of the S61N include?
- weight of fixed ballast
- unusable fuel supply
- undrainable oil
- total quantity of hydraulic fluid
- *excludes the weight of crew, payload, and fuel
What are the engine operating limits for sea level, standard day conditions for takeoff? one eng inoperative 2.5 minute? one eng inoperative up to 30 minutes? maximum continuous?
- takeoff, 5 minutes:
- - 1400 SHP
- - 21275 rpm 112% Nf
- - 26300 rpm/100% Ng
- - 696C T5
- One Eng inoperative, 2.5 minutes:
- - 1500 SHP
- - 21275 rpm/112% Nf
- - 27200 rpm/103.4% Ng
- - 758C T5
- One Eng inoperative, up to 30 minutes:
- - 1400 SHP
- - 21275 rpm/112% Nf
- - 26300 rpm/100% Ng
- - 696C T5
- Maximum continuous, unlimited time frame:
- - 1250 SHP
- - 21275 rpm/112% Nf
- - 26300 rpm/100% Ng
- - 660C T5
What is the maximum transient temperature? maximum starting temperature? Abort start temperature? limit for CT58-140-2 engine?
- maximum transient: 841C for 2 seconds
- starting: 950C for 2 seconds
- abort start: 750C
What is the maximum allowable overspeed for CT58-140-2 engine?
- 23100 rpm/122% Nf is when overspeed is activated
- 27600 rpm/105% Ng for 15 seconds
When must an engine be inspected?
- if takeoff power is used in cumulative excess of 5 minutes during any one emergency
- the time in excess of 5 minutes and the maximum levels of T5, Ng, Q, and total time are to be recorded
What happens to CT58-140-2 engines when operating below 15C and 4C?
below 15C: takeoff power increases to a maximum of 1540 SHP at -54C. Maximum continous power increases to a maximum of 1390 SHP at 4C. This increase in SHP is also authorized for use at any ambient temperature for engines whose individual charactersitics permit higher than normal powers to be developed without exceeding existing temperature or rpm limits.
What are the flight limitations for Category A & B operations:
- 1. no acrobatic maneuvers approved
- 2. VNE: 131 KIAS (with 0 instrument error) at 100% rotor speed (Nr). For variation of VNE with density altitude and take-off gross weight, see figre 1-22 and VNE placard. With AFCS engaged and at speeds within 5 knots of VNE speeds, a malfunction which results in a dive may increase the helicopter's speed 5 knots beyond the VNE speed
- 3. Operations are not approved for operating in icing conditions
- 4. Prior to entering HIR conditions, all axes of the AFCS must be engaged and operating properly
- 5. HIR speed range: 45 KIAS - VNE as outlined in 2
- 6. avoid prolonged hover in crosswind, or tail into wind, to prevent accumulation of exhaust fumes in the cockpit or cabin
- 7. all fuel boost pumps are required under any of the following conditions: above 5000' PA, fuel temperature above 110F, with 20 minutes of fuel remaining. Use of one boost pump per tank is required at all times except as limited by PA and 20 minutes of fuel remaining
- 8. Crossfeed permitted in emergency operations only Cat A, and cruising flight only for Cat B
What are the crosswind limitations for aircraft with honeycomb core TR blades? with Ribbed pocket TR blades?
- honeycomb TR blades: 17 KIAS
- Ribbed pocket blades: not limited in crosswind operation or sideward flight and have been evaluated during certification flight tests to 30 KIAS
What does the tail rotor negative force gradient system do?
The TR negative force gradient system is installed to relieve the pilot of TR forces created by aerodynamic loads when the auxiliary servo system is inoperative. The system applies a force to cancel the aerodynamic loads when the TR is operating at normal speeds. Because of this, when the system is checked on the ground with the TR stationary and the auxiliary servo off, the negative spring centering effect is created. The normal tendency of the pedals then is to go to either extreme. Under these conditions, considerable force is required to push the TR pedals from the extreme position: however, the forces will decrease as they approach neutral position. The initial force to move the pedals toward the right from full left position is between 30-40 lbs.
What is the maximum authority for pitch, roll, and yaw with the AFCS system?
- Pitch: 7.5%
- Roll: 10%
- Yaw: 5%
What does the emergency Lubrication system for the main gearbox do?
provides pressure lubrication to the high-speed section and the transmission oil pressure gauge, should the normal oil pressure system fail. It can also be used to pre-lubricate the high-speed input end of the main gearbox should there be a failure to the motorized system
Describe the Emergency Lubrication System for the Main gearbox:
The system consists of an auxiliary oil sump connected to the bottom of the main gearbox, an electric pump, a PUMP ON advisory light, and a switch. The system operates on 28V from the DC essential bus. The DC system is activated by a 7 +/- 1 psi pressure switch located at the front of the gearbox. During flight, the switch is normally set to ARM and the emergency lube pump will automatically switch ON should the transmission oil pressure switch sense a loss of pressure in the main gearbox.
What is powered in the accessory section of the main gearbox?
- #1 generator 8010 rpm
- #2 generator 8010 rpm
- Primary Hydraulic pump 3738 rpm
- DC generator/Motor generator 8131 rpm
- Auxiliary hydraulic pump 3709 rpm
- TR drive/takeoff 3030 rpm
- Nr tach generator 3902 rpm
- Torque Meter Oil Pump and filter 2510 rpm
- MGB oil pump and filter 2510 rpm
What is TTO?
This is an accessory drive through-shaft which turns only when the #1 engine is operating, and the rotors are turning. During normal operation the through-shaft (input of 8100 rpm) merely provides a redundant power path for driving the accessories, which are normally driven by the tail takeoff through a free wheel unit 8410 rpm. However, should a malfunction of this free-wheel unit occur, the through shaft would assume the task of driving the accessories by providing a power path direct from the #1 engine to the accessories.
What rpm does the main spiral bevel pinion rotate at? main spiral bevel gear? Main rotor shaft?
- main spiral bevel pinion: 3195 rpm
- main spiral bevel gear: 939 rpm
- main rotor shaft: 203 rpm
What do the supervisory panels do?
- Should a problem be sensed, the relevant line contactor will be de-energized, the generator excitation circuit will disconnect, thus disabling the generator:
- undervoltage protection: min 100V for 6 seconds or more
- Overvoltage protection: > 125 V for 1 second
- during ground operatrions: Underfrequeny protection: < 375 Hz for 3 seconds