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 1997 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.
3、S.A.QUESTIONS REGARDING THIS DOCUMENT: (412) 772-8510 FAX: (412) 776-0243TO PLACE A DOCUMENT ORDER: (412) 776-4970 FAX: (412) 776-0790400 Commonwealth Drive, Warrendale, PA 15096-0001AEROS PACE INFORM ATION REPORTSubmitted for recognition as an American National StandardAIR1850 RE V. AIssued 1989-03
4、Revised 1997-06Superseding AIR1850T win E ngine H elicopter P ower R equirementsFOREWORDChanges in this revision are format/editorial only.1. SCOPE:This SAE Aerospace Information Report (AIR) defines the power spectrum during normal and emergency operations of a twin engine helicopter and thereby po
5、stulates suitable power plant rating structures. This document does not address the power requirements for single engine helicopters or those with more than two engines.2. REFERENCES:There are no referenced publications specified herein.3. ENGINE RATINGS:Rating structures are used to define “time at
6、 power” which enables a helicopter to achieve its optimum performance while, at the same time, addressing issues of airworthiness and safety.The rating structure is the means by which the engines life consumption in service is related to its output power capability as demonstrated in the manufacture
7、rs qualification program.Factory engine testing to these specific ratings, which are imposed as mandatory limits on the pilot, forms a practical but approximate method of limiting the rate of engine life consumption in order to achieve acceptable in-service lives.SAE AIR1850 Revision A- 2 -4. RATING
8、 DEFINITION:A rating is defined as a minimum power level, delivered at specified atmospheric conditions for a maximum specified time duration, without exceeding operating limits over the life of the engine. For example, a “takeoff” rating, at sea level, ISA which can be used only during that phase o
9、f flight, and is limited in duration to “x” minutes, will be restricted to the appropriate engine speed, turbine temperature and torque limits. All ratings must be demonstrated during certification and the ratings may, or may not, be demonstrated during the acceptance process.A rating is recognized
10、by the airworthiness authorities as a restriction for safety consideration but may sometimes be imposed by the engine manufacturer as a commercial consideration.5. HELICOPTER ROLES:The rest of this document considers firstly the power requirements for various operations and flight conditions of the
11、twin engine helicopter and secondly how the engine ratings can be structured to accommodate these requirements, while giving due consideration for engine service life.The use of helicopters is broadly summarized as follows:TABLE 1Operator Role Critical ConsiderationsMilitary that is, it is not physi
12、cally checked in service but is predicted from the trending of the power assurance testing.It is physically checked by the manufacturer at engine certification and possibly at acceptance test both in terms of power availability and of limitation. This can be achieved most benignly at low inlet tempe
13、ratures, to avoid overtemperatures of the turbine.An appropriate number of applications in service may be three times in one flight since it may be used once at the point of failure, once during a subsequent landing waveoff and once during the subsequent landing. After application, appropriate maint
14、enance action must be taken according to engine manufacturer specification.TWIN OEI1. Takeoff & Land 5 min 1.0 1. Emergency 30 s 1.252. Continuous Unlimited 0.8 2. Climb Out/ 2 min 1.10contingency3. Max Continuous Continuous 0.95-1.05OEIFIGURE 3SAE AIR1850 Revision A- 8 -6.1.2 Emergency Climb Out: T
15、his can be limited to 2 min as representing a reasonable time for modern helicopters to climb out to a safe height following an engine failure at CDP. Like the emergency rating, it is expected to require life tracking.6.1.3 OEI Cruise: It is recommended that a continuous duration be authorized for t
16、his rating. The power level should be 0.95-1.05 x takeoff depending on aircraft mission (critical military maneuver vs. commercial enroute cruise).6.1.4 Twin Takeoff: This is the base power level but it is recommended that its duration may be limited to 5 min which would be operationally adequate.6.
17、1.5 Cruise: Unlimited usage resulting in no significant life usage.6.1.6 Other Considerations: As suggested in Section 4, the power levels for other specialized roles of the helicopter should be considered as amendments or modifications of the basic transportation role.The most significant differenc
18、e for the other roles is the almost universal need to provide power level/duration for extended periods of hover and in general a reduction in engine life is expected if this capability is to be provided over a wide operational envelope.As more elaborate and complex combinations of rating structures
19、 are developed for specialized applications, it becomes increasingly important to establish rigorous power assurance checks in-service and rely on the latest generation of control and engine condition monitoring systems to track life-limited hardware in-service.PREPARED BY SAE COMMITTEE S-12, HELICOPTER POWERPLANT
