Power plant installation
ENGINE AND JET PIPE MOUNTINGS
13. The engine is mounted in the aircraft in a manner that allows the thrust forces developed by the engine to be transmitted to the aircraft main structure, in addition to supporting the engine weight and carrying any flight loads. Because of the wide variations in the temperature of the engine casings, the engine is mounted so that the casings can expand freely in both a longitudinal and a radial direction. Types of engine mountings, however, vary to suit the particular installation requirement. Turbo-jet engines are usually either side mounted or underslung as illustrated in fig. 23-11. Turbo-propeller engines are mounted forward on a tubular framework as illustrated in fig. 23-13.
Power plant installation
14. The jet pipe is normally attached to the rear of the engine and supported by the engine mountings. In some installations, particularly where long jet pipes are employed, an additional mounting is provided, usually in the form of small rollers attached to each side of the jet pipe. The rollers locate in airframe-mounted channels and support the weight of the jet pipe, whilst still allowing it to freely expand in a longitudinal direction.
ACCESSORIES
15.
An aircraft power plant installation generally includes a number of accessories that are electrical-ly operated, mechanically driven or driven by high pressure air.
16.
Electrically operated accessories such as engine control actuators, amplifiers, air control valves and solenoids, are supplied with power from the aircraft electrical system or an engine driven dedicated electrical generator.
17.
Mechanically driven units, such as generators, constant speed drive units, hydraulic pumps, low and high pressure fuel pumps, and engine speed signalling, measuring or governing units are driven from the engine through internal and external gearboxes (Part 7).
18.
Air-driven accessories, such as the air starter and possibly the thrust reverser, afterburner and
water injection pumps, are driven by air tapped from the engine compressor. Air conditioning and cabin pressurization units may have a separate air-driven compressor or use air direct from the engine compressor. The amount of air that is taken for all accessories and services must always be a very small percentage of the total airflow, as it represents a thrust or power loss and an increase in specific fuel consumption.
COWLINGS
19.
Access to an engine mounted in the wing or fuselage is by hinged doors; on pod and turbo-propeller installations the main cowlings are hinged. Access for minor servicing is by small detachable or hinged panels. All fasteners are of the quick-release type.
20.
A turbo-propeller engine, or a turbo-jet engine mounted in a pod, is usually far more accessible than a buried engine because of the larger area of hinged cowling that can be provided. The accessibility of a podded turbo-fan engine is shown in fig, 23-12 and that of a turbo-propeller engine is shown in fig, 23-13.
I.A.E. International Aero Engines V2500
Design of the RB162 began in 1959 using experience, gained on the RB108, of simplified lightweight constructions and systems. These measures, combined with lightweight materials, served to keep the engine weight down to 280 lb; giving a thrust to weight ratio of 16:1. First run in December 1961, the RB162 was used to provide lift for a
Rolls-RoyceRB 162
variety of VTOL research aircraft.
24: Maintenance
Contents Page
Introduction 251 On-wing maintenance 252 Scheduled maintenance Unscheduled maintenance Condition monitoring 252 Flight deck indicators In-flight recorders
Ground indicators Maintenance precautions 254 Trouble shooting 254 Adjustments 256 Ground testing 256
INTRODUCTION
1.
Maintenance covers both the work that is required to maintain the engine and its systems in an airworthy condition while installed in an aircraft (on-wing or line maintenance) and the work required to return the engine to airworthy condition when removed from an aircraft (overhaul or shop maintenance). On-wing maintenance is covered in this Part; overhaul is covered in Part 25.
2.
Because many aspects of maintenance are subject to the approval of a recognized authority, it should be fully understood that the information given in this Part is of a general nature and is not intended as a substitute for any official instructions.
3.
The comprehensive instructions covering the actual work to be done to support scheduled maintenance (para. 8) and unscheduled maintenance (para. 10) are contained in the aircraft maintenance manual. Both this publication, and the aircraft maintenance schedule mentioned in para. 8, are based on manufacturers' recommendations and are approved by the appropriate airworthiness authority.
4.
The maximum time an engine can remain installed in an aircraft (engine life) is limited to a fixed period agreed between the engine manufacturer and airworthiness authority. On some engines this period is referred to as the time between overhaul (T.B.O.) and on reaching it the engine is removed for complete overhaul.
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