Type of Engine
T700-GE-401C
Horse Power
1662 SHP Continuous
1800 SHP 30 min
1940 SHP 2.5 minutes
Dimensions
Length, MR Diameter, TR Diameter, Wheel Base, Height, Width, Ground Clearance
Length Overall- 64' 10" Main Rotor Diameter- 53' 8" Tail Rotor Diameter- 11' Wheel Base- 29' Height- 17' Width- 7' 9" Ground Clearance- 1' 7"
Flow of Air Through Engine
Inlet (5th stage bleed air via engine AI/SB valve)
Swirl (Imparts Rotation)
IPS (Throws Particles Outward)
Collection Scroll (Particles Collected)
Scroll Vanes (Contained in collections scroll)
Deswirl (removes rotation)
Compressor (smooth, particle free air)
Ng Turbine
- Two Stages
- Drives Compressor and AGB
Np Turbine
- Two Stages
- Np Shaft is inside Ng Shaft
- Connects to High Speed Shaft, which connects to input module
Engine Air Used For Combustion
30%, remaining used for
- 1) T2 (Compressor Inlet Temperature Air)
- 2) P3 (Compressor Discharge Pressure Air)
- 3) Combustor and Turbine Cooling
- 4) Engine Oil Seal Pressurization
Major Components of Engine
HMU, ODV, DECU, Alternator, and Fuel Flow Valves
Basic Operation
- Maintain Constant Np/Nr
- Interaction of DECU and HMU
- HMU provides Gas Generator control while DECU trims HMU down to meet demands of Np, ultimately reducing pilot workload
Load Demand Spindle
- HMU responds quickly to collective position via load demand spindle
Inputs to HMU (5)
- Collective via LDS
- PCL via PAS
- Variable Stator Vanes and AI/SB valve positioning is controlled in response to T2, P3, and Ng
1) Fuel Shutoff
2) Automatic Acceleration to Ground Idle
3) Set up to Max permissible Ng
4) Fuel Priming
5) DECU Lockout
HMU Operation
- Basic Gas-Gen power control with no input from Torque Motor Servo
- Fuel Enters through Pump, routed to metering valve
- LVDT provides feedback to DECU to prevent hunting
Ng Ovespeed Valve
110 +- 2%
HMU provides higher then required power for 2 reasons:
1) Fail Safe to High Power
2) Power Available with One Engine Inop (OEI)
HMU Functions (6)
1) Ng Governing
2) Ng Overspeed Protection
3) Flame-out/Compressor Stall Protection
4) Acceleration Limiting
5) Automatic Fuel Scheduling For Engine Start
6) Rapid Engine Response through Collective Compensation
ODV Fuctions (4)
1) Provide fuel to 12 injectors
2) Returns fuel to HMU if Np overspeed
3) Purges fuel downstream to prevent injector coking
4) Traps fuel upstream to prevent priming
Harness Colors
Yellow- Power and control system signals Blue- Np, Np overspeed, and Torque signals Green- Engine Diagnostics White- Engine Cross Talk Red- EDECU
DECU Functions (15)
1) Np Governing
2) Np Overspeed Protection (120%)
3) Np Overspeed Test (re-base to 96%)
4) Ng Decay Relight Feature (Disabled below 62% NG)
5) TGT Limiting (Limiter at 839% +- 10%)
6) Auto Ignition (On for 5 seconds after Np Overspeed or Np Overspeed Test)
7) Contingency Power (Limiter at 891% +- 10%)
8) Hot Start Prevention (Stops fuel if 900 C prior to Ng 60% and Np 50%. Restored once TGT Decreases Below 300 C or 25 seconds)
9) DECU Lockout (Manual control of Fuel, lose Load Sharing, Np Governing, and TGT Limiting. Retain Np Overspeed Protection)
10) Engine Load Sharing (Increases power of lower Torque)
11) Fault Diagnostics (Other engine Off, 400 HZ power, Np < 35%, Ng <20%)
12) Engine Speed Trim (96-101)
13) Cockpit Signals (Np, TGT, TQ)
14) Transient Droop Improvement (Increases Fuel flow through TDI sensor at low Torque settings when collective demand is increases rapidly)
15) 400 HZ Back Up Airframe Power (Receives airframe electrical power if alternator Fails)
EDECU Functions (3)
1) Manual C-Power (891% +-903%)
2) Auto C-Power (If <50% on other Engine)
3) TGT (866 +-10%)
Oil System Pumps
1 Pressure, 6 Scavenge Lines
Oil Flow
Tank, AGB Pump, Filer/Bypass, Pressure Sensor, Temp Sensor, Cold Oil Relief, Sumps, Scavenge lines, Oil Cooler or Oil Cooler Bypass or Scroll, Tank
3 ways to anti-ice Engine
1) Vent bleed air into swirl vanes via AI/SB valve
2) Vent bleed air into inlet via AI/SB valve
3) Pump Oil through Scroll Vanes
4 Indications of Malfunctioning Engine Anti-Ice/Start Bleed Valve
1) ENG ANTI ICE ON Appears >90% Ng
2) ENG ANTI ICE ON Disappears <88% Ng
3) No ENG ANTI ICE ON with switch ON
4) No rise in TGT with ENG ANTI ICE ON
- Possible diversion of Fuel in the case of VG Vane hangup may cause flame-out*
- Up to 18% TQ lost with ENG ANTI ICE ON*
Inlet Anti-Ice Valve
- Freon Filled Bellows
- Heats air to 94 deg F
- Fully Open 13 def F
- Inlet Anti Ice Switch must be ON to work*
- DC power removed = full open*
- Up to 49% TQ Lost*
