|AE 1107C Specifications
Takeoff (SL,103 F)
OEI (SL, 90 F)
Cruise (20k, 0.55 Mn)
The V-22's propulsion system consists of dual counter rotating proprotors attached to gearboxes driven by Allison AE 1107C turboshaft engines. The engines, proprotor gearboxes (PRGB), tilt-axis gearboxes (TAGB), proprotor controls, and infrared (IR) suppressors are all housed in the rotating nacelle on the end of each wing. An interconnecting drive shaft transfers power from each nacelle to the mid-wing gearbox (MWGB). This is the heart of the tiltrotor technology.
The AE 1107C provides the V-22 Osprey a modern, rugged powerplant. Advanced technology features include; all-axial high efficiency turbo-machinery components, only four main rotor bearings, positive sump scavenging, modular construction and dual independent Full Authority Digital Engine Control (FADECs). The AE 1107C is capable of developing over seven shaft horsepower per pound of weight - the highest ratio of any engine in its class. Its modern design offers a versatile core common to the AE 2100 turboprop and AE 3007 turbofan engines. The core technology benefits from 200 million T56 operating hours across the full range of military operations and over one million hours on the Rolls-Royce AE family of engines.
The two-shaft axial design consists of a 14-stage compressor followed by an effusion-cooled annular combustor, a two-stage gas generator turbine and a two-stage power turbine. It features six rows of variable compressor vanes, dual FADEC, a self-contained oil system that allows for vertical operation, modular construction, and an 'on-condition' maintenace capability.
Commercial products like the Allison AE-1107C engine provide high quality systems at market controlled prices. On 3 May 1999 the V-22 program received the 1999 Department of Defense Acquisition Executive's Certificate of Achievement from the Assistant Secretary of the Navy for Research, Development and Acquisition. The award cited that a contract through which Allison would provide maintenance and supply support for the AE-1107C engine would save millions of dollars. This contract is known as "Power by the Hour" because Allison provides the majority of the maintenance and supply support beyond the flight line. This support includes configuration management, training, spare parts inventory and engine certification. It is estimated that the Power by the Hour Program could ultimately save the Department of Defense more than $533 million by avoiding costly investments in engine logistics infrastructure. This collaborative Department of Defense effort began in 1996, culminating with a May 1998 contract award, which program officials believe is an approach that could be a watershed event in future logistics support program planning. During this two-year effort, a side-by-side comparison was made of engine life cycle costs for a commercial engine supported by Power by the Hour versus a military engine operating with internal military support. The latter was more costly because of the infrastructure investment required for military support.
|Under normal, two engine operations, each engine delivers its power to its corresponding proprotor through the PRGB. Only a small amount of power (511 hp max) is transferred down the pylon mounted drive shaft, through the TAGB and down the interconnecting drive shaft to the MWGB. The MWGB contains the auxiliary power unit (APU), the constant frequency generator and the variable frequency generator. The MWGB transmits power between the left and right interconnecting drive shafts without changing speed or direction of rotation.|
|During single engine operation, power is distributed from the remaining engine to both proprotors through the interconnecting drive shaft. This diagram shows this condition with the right engine failed.|
|The V-22 is equipped with two counterrotating three-bladed proprotors. The blades are constructed primarily of composite material with a metallic leading edge abrasion strip and integral de-ice blanket. These blades are attached to the proprotor hub which transmits drive torque to the proprotor. The proprotor controls respond to cyclic, directional, and thrust lever inputs in helicopter and conversion modes, and to thrust inputs alone in airplane mode. Vibration reduction has been designed into the entire proprotor assembly including the pendulum dampers used to reduce the vibratory loads generated by the rotation of the proprotors.|
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