1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and enginee ring sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefr
2、om, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invit es your written comments and suggestions.Copyright 1998 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.
3、S.A.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8510 FAX: (724) 776-0243TO PLACE A DOCUMENT ORDER: (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.org400 Commonwealth Drive, Warrendale, PA 15096-0001AEROS PACE INFORM ATION REPORTSubmitted for recognition as an American National Stan
4、dardAIR4281Issued 1998-11Oil Systems for Helicopter PowerplantsFOREWORDOil systems for helicopter powerplants should be optimized with respect to both engine and airframe.a. Engine: The oil system has to enable satisfactory operation within the specified limits (ambient temperature, power, etc.)b. A
5、irframe: Integration of the engine and associated oil system components into the airframe without adverse effects on helicopter or airframe architecture, reliability maintainability, performance, etc.In order to enhance integration and proper operation of the engine, as well as maintainability and r
6、eliability of the entire system, the following items should be considered:a. Minimization of engine/airframe interfacesb. Use of identical components for systems with similar tasks on engine and airframe, e.g.:(1) lubrication fluid(2) fittings(3) filters, etc.A detailed schematic of a typical oil sy
7、stem is shown in Figure 1.SAE AIR4281 - 2 -FIGURE 1 - Schematic of a Typical Oil SystemSAE AIR4281 - 3 -1. SCOPE:Turbine engines installed in helicopters require a highly sophisticated oil system to fulfill two tasks:a. Cooling/oil supplyb. LubricationWhile lubrication is an engine internal procedur
8、e, cooling and oil supply require more or less design activity on the aircraft side of the engine/airframe interface for proper engine function, depending on the engine type.The necessity for engine cooling and oil supply provisions on the airframe can lead to interface problems because the helicopt
9、er manufacturer can influence engine related functions due to the design of corresponding oil system components.This SAE Aerospace Information Report (AIR) deals with integration of engine oil systems with the airframe and gives information for both helicopter and engine manufacturers for a better u
10、nderstanding of interface requirements.2. APPLICABLE DOCUMENTS:Further information concerning oil system design, operation, installation, and testing is given in the following documents:2.1 FAA Publications:Available from Federal Aviation Administration, 800 Independence Avenue, SW, Washington, DC 2
11、0591.2.1.1 FAR Regulations:Part 27 - Airworthiness Standards: Normal Category Rotorcraft; Subpart E - Powerplant, paragraphs 27.1011 through 27.10.21 (Oil System)Part 29 - Airworthiness Standards: Transport Category Rotorcraft; SubpartE - Powerplant, paragraphs 29.1011 through 29.1025Part 33 - Airwo
12、rthiness Standards: Aircraft Engines; Subpart B - Design and Construction; General paragraph 33.17 - Fire preventionSubpart E - Design and Construction; Turbine Aircraft Engines; paragraph 33.71 - Lubrication systemSAE AIR4281 - 4 -2.2 Military Publications:Available from Standardization Documents O
13、rder Desk, Building 4D, 700Robbins Avenue, Philadelphia, PA 19111-5094.Military Specification MIL-O-19838 (Aer): Oil Systems, Aircraft, Installation and Test(It should be noted that this MIL-Spec. provides a general definition for aircraft propulsion.)2.3 Other Documents:British Civil Airworthiness
14、Requirements, Section C: Sub-Section C4 - Turbine Engines for Rotorcraft, Chapter C4-2 Design and Construction; paragraph 2.2 Oil System3. COOLING AND OIL SYSTEM CONCEPTS:From the point of view of engine/airframe interfaces, three cooling/oil system concepts have to be considered:a. Self-contained o
15、il systemb. Partially self-contained oil systemc. Airframe supported oil system3.1 Self-Contained Oil System (Figure 2):A self-contained oil system means that all components necessary for engine oil supply and oil cooling are an integral part of the engine. No provisions are necessary on the airfram
16、e.Oil supply is achieved by an oil tank integrated within the engine structure.Engine cooling is obtained by engine internal cooling provisions such as:a. Fuel cooled oil coolersb. Air/oil cooling devicesc. A combination of bothThe fuel cooled oil cooler transfers the heat from the oil to the fuel c
17、onsumed by the engine.For air/oil cooling, the heat is transferred to the engine inlet air. In addition, such a system can provide anti-icing functions for certain sections of the engine air inlet structure.However, consideration should be given to the fact that transfer of heat to the engine intake
18、 will cause a performance penalty. For such a system a means should be provided which prevents heated portions of inlet air from entering the core engine.SAE AIR4281 - 5 -FIGURE 2 - Self-Contained Oil System(No Vital Interfaces Engine/Airframe)3.1 (Continued):A self-contained engine oil system is th
19、e simplest solution for integration of an engine into a helicopter. No engine/airframe interfaces are necessary which could adversely affect engine oil system functions.The responsibility for the complete engine oil system rests with the engine manufacturer.This concept can easily be realized for en
20、gines which do not have an integrated reduction gearbox (generally bigger engines with output power greater than 1000 Kw) since this feature provides a reduced amount of engine oil and a reduced heat rejection.SAE AIR4281 - 6 -3.2 Partially Self-Contained Oil System (Figure 3):A partially self-conta
21、ined oil system does not have all the components necessary for engine oil supply/oil cooling located on the engine. Some components have to be provided on the airframe and, thus, are the responsibility of the helicopter manufacturer. The airframe part of a partially self-contained oil system is gene
22、rally related to cooling air supply.The engine is equipped with all components necessary for oil supply, oil conditioning, and oil transport (integrated oil tank, pumps, lines, filter units, etc.). For oil cooling, an air/oil cooling unit is provided on the engine which needs cooling air in addition
23、 to the airflow necessary for engine operation. Cooling airflow is usually provided by an engine driven blower (air/oil-cooler and blower may be designed as one common unit).It is the helicopter manufacturers responsibility to provide sufficient cooling air supply and a cooling air outlet. For this,
24、 corresponding air ducts have to be provided on the airframe.The airframe/engine-interface for such a configuration will be between the air ducts (inlet and outlet) and the engines cooling unit.In order to ensure proper cooling system operation, the engine manufacturer has to specify the cooling sys
25、tems operating data including worst case conditions (cooling air mass flow, etc., see 4.1). These data are required by the airframe manufacturer for design and dimensioning of the cooling air inlet and outlet ducts.For structural integration of the cooling system into the airframe, the following int
26、erface information has to be provided by the engine manufacturer:a. Engine cooling system cooling air inlet and outlet connection flange definition:(1) location(2) shape(3) dimensions(4) type of connecting device(5) maximum allowable connecting loadsb. For cooling system integration:(1) the engine c
27、ooling system has to be optimized with regard to size, weight, maintainability (e.g., reduction of cooling air duct size; accessibility to connecting devices for the installed engine)(2) on the airframe it must be ensured that:(a) the cooling air supply/exhaust-conditions required for the engine coo
28、ling system will be met by the air duct designSAE AIR4281 - 7 -FIGURE 3 - Partially Self-Contained Oil System3.2 (Continued):(b) the supply and outlet ducts are located and routed such that the ingestion of exhausted cooling air or other hot gases (engine exhaust gas) will be avoided(c) the cooling
29、air outlet ducts will be routed such that exhausted cooling air cannot be ingested by engine air inlets(d) the cooling air inlet opening is protected against ingestion of foreign objects which could clog the supply duct or damage cooling system components (e.g., installation of an inlet screen)SAE A
30、IR4281 - 8 -3.2 (Continued):(e) design and location of cooling air inlets and ducting is such that even with adverse weather effects (e.g., icing or snow accumulation) satisfactory operation of the engine cooling system is givenEngines featuring a self-contained or partially self-contained oil syste
31、m require the helicopter drive system to provide two separate oil cooling units at different locations:a. Engine oil cooling unit located on the engineb. Main transmission oil cooling unit located on the airframe. (For partially self-contained oil systems, an alternative concept could be a common bl
32、ower for the engine and transmission coolers.)For such systems the arrangement of the engine and main transmission has to be considered.Depending on the helicopter design and engine design, the engine(s) can be located in front of the main transmission or behind the main transmission.If the engines
33、are located in front of the main transmission, main transmission cooling may be affected by heat emanating from the engines.If the engines are located behind the main transmission, the influence is reverse.3.3 Airframe Supported Oil System (Figure 4):3.3.1 General: Small turbine engines (power class
34、 up to 600 Kw, see Table 1) require vital oil system components on the airframe. Since the main components for oil supply, oil cooling, and oil transport are the helicopter manufacturers responsibility, it is defined as an “airframe supported oil system“.For this configuration the engine is equipped
35、 with an internal lubrication circuit. This lubrication circuit typically contains engine driven pressure and scavenge oil pumps, a filter unit, a high pressure regulating valve or a pressure regulating valve, and internal lines for transportation of lubricating fluid. The engine/airframe interfaces
36、 for an airframe supported oil system are the oil system feed and scavenge ports on the engine. The position of these ports should be clearly defined by the engine manufacturer. The location should provide good accessibility for the connection of the airframe provided feed and scavenge lines. The po
37、rts on the engine should be designed such that standard connectors and fittings can be used.SAE AIR4281 - 9 -FIGURE 4 - Airframe Supported Oil SystemSAE AIR4281 - 10 -TABLE 1 - Engine Oil System ExamplesEngine TypeEngine PowerKwEngine PowerhpEngine GearboxConceptOil SystemCoolingConcept RemarkAlliso
38、n 250 series 313-485 420-650 Integrated reductiongearboxCPratt+Whitney200 series440 590 Integrated reductiongearboxCTurbomeca TM 319 340 456 Integrated reductiongearboxCTurbomeca ARRIEL 1C 492 660 Integrated reductiongearboxCLycoming LTS101-650B-1410 550 Integrated reductiongearboxCTurbomeca TM 333
39、A 635 850 Integrated reductiongearboxCGeneral Electric T64 2387-3282 3200-4400 No reduction gearbox C No oil tank/coolerGeneral Electric T58 746-1395 1000-1870 No reduction gearbox B No oil tankTurbomeca TM 333 B 750 1005 Integrated reductiongearboxBAllison-GarretT800-LHT-800986 1320 No reduction ge
40、arbox B Cooling airMTU-Turbomeca-Rolls-Royce MTR390950 1273 Integrated reductiongearboxB Duct necessaryTurbomeca MAKILA 1400 1876 No reduction gearbox ARolls-Royce/Turbomeca RTM3221566 2100 No reduction gearbox AGeneral ElectricT700/CT71044-1492 1400-2000 No reduction gearbox ANOTES:Concept A: Self-
41、contained, no components, specific device or arrangement on the airframe side necessaryConcept B: Partially self-contained, some devices or arrangements may be provided by the airframe manufacturerConcept C: Airframe supported oil system; some vital parts of the oil system are provided by the airfra
42、me manufacturer (such as oil tank cooling system)SAE AIR4281 - 11 -3.3.1 (Continued):The following components have to be provided on the airframe to permit proper operation of the engine lubrication system:a. Oil tankb. Oil cooling systemc. Feed line (oil tank/engine oil system feed port connection)
43、d. Scavenge line (engine oil system scavenge port/oil cooling system connection)Depending on the engine design, some additional components may be required on the airframe side by the engine manufacturer, e.g.:a. Scavenge oil filterb. Chip detectorFor design and arrangement of the airframe part of th
44、e oil system, structural interference with other helicopter systems and components has to be considered. The airframe oil systems complexity should be minimized.For instance, an engine external scavenge oil filter requires a lot of operating data coordination between the engine and airframe manufact
45、urers and increases oil system complexity.Components like filters and chip detectors can be integrated into the engine structure, even for small turbine engines.To permit proper operation of the entire oil system, the engine manufacturer has to provide all the data necessary for operation of the eng
46、ines internal lubrication system. These data (minimum engine oil inlet pressure, inlet oil temperature range, etc., see 4.1) have to be considered by the airframe manufacturer when designing the engine external oil system components.When defining operational requirements, the engine manufacturer sho
47、uld consider that engine operating data will influence the size and position of oil system components on the airframe and, thus, will affect the integration of the engine. The oil tank and the cooling system are components on the airframe which, due to their size, have the most effect on airframe de
48、sign.For that reason the engine internal lubrication circuit should be optimized so that the smallest oil tanks and coolers can be used.When engine isolation is required for a multiengine helicopter, the oil system is affected.Separate oil tanks, oil coolers, and the associated plumbing have to be p
49、rovided for each engine.SAE AIR4281 - 12 -3.3.2 Oil Tank: There are two varieties of oil systems: hot tank and cold tank. A hot tank system uses scavenge pumps to return oil directly to the tank. From there the main oil pump delivers oil to the engine components through an oil cooler and filter. Because some cooling takes place in the tank, the oil is deaerated by settling in the tank, and the oil is under main pump pressure. It is claimed that oil cooler dimensions can be minimized.In a cold tank system, the scavenge pump(s) pass the oil
