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Standard

Engine Erosion Protection

1971-02-01
CURRENT
AIR947
This Aerospace Information Report deals with protection of helicopter aircraft engines against erosion. Applicability is restricted to aircraft having a disc loading of less than 15 pounds per square foot.
Standard

POWER AVAILABLE AND INLET DISTORTION CONSIDERATIONS FOR ROTORCRAFT INLET BARRIER FILTER INSTALLATIONS

2018-12-04
WIP
AIR6980
This Aerospace Information Report (AIR) identifies considerations on power available and inlet distortion for rotorcraft with Inlet Barrier Filter (IBF) installations. This document provides a more in-depth understanding of the physics behind power available and inlet distortion characterization for rotorcraft with Inlet Barrier Filter (IBF) installations, including case studies and calculation examples. It is intended to support the methods of compliance to power available and inlet distortion requirements for rotorcraft with Inlet Barrier Filter (IBF) installations recommended in ARP6912.
Standard

CONCURRENT DESIGN OF ENGINES AND SPECIFICATIONS OF STARTING SYSTEMS FOR HELICOPTERS

1975-10-01
CURRENT
AIR1296
It is recommended that all helicopter engine development programs include an evaluation of engine starting requirements. The evaluation should include starting requirement effects on helicopter weight, cost, and mission effectiveness. The evaluation should be appropriate to the engine stage of development.
Standard

Cockpit Information Required for Helicopter Turbine Engine Operation and Maintenance

1997-06-01
CURRENT
AIR1963A
This SAE Aerospace Information Report (AIR) identifies Propulsion Engineer’s recommendations for the instrumentation that is required for the safe operation and maintenance of turbine engines as installed in helicopters. It should be used as a guide for cockpit layout, as well as a reference for maintenance considerations throughout the propulsion area. Propulsion instruments should receive attention early in the design phase of the helicopter. Maintenance and diagnostics recorders are not considered within the scope of this document. (See ARP1587, “Aircraft Gas Turbine Engine Monitoring System Guide”.)
Standard

HELICOPTER TURBOSHAFT ENGINE IDLE POWER SCHEDULING

2018-08-09
WIP
AIR4121
The purpose of this AIR (Aerospace Information Report) is to provide aircraft and engine designers with a better understanding of helicopter turboshaft engine idle power characteristics and objectives to be considered in the design process. Idle is the lowest steady state power setting. At this setting, the engine typically does not produce enough power to obtain governed output shaft speed (i.e. the shaft speed is determined by the load imposed by the aircraft). In the aircraft, the engine is typically stabilized at this power setting after starting, prior to taxi and for some period of time after rotor shutdown for cool down prior to engine shutoff. Traditionally, the aircraft designer wants idle power scheduled as low as possible and of course, does not want any resulting aircraft operational difficulties such as overcoming the rotor brake. The engine designer, however, desires a higher scheduled power because of the reduced probability of engine operational problems.
Standard

The Effect of Installation Power Losses on the Overall Performance of a Helicopter

2005-06-07
CURRENT
AIR5642
The purpose of this SAE Aerospace Information Report (AIR) is to illustrate the effect of installation power losses on the performance of a helicopter. Installation power losses result from a variety of sources, some associated directly with the basic engine installation, and some coming from the installation of specific items of aircraft mission specific equipment. Close attention must be paid to the accurate measurement of these losses so that the correct aircraft performance is calculated. Installation power losses inevitably result in a reduction in the overall performance of the aircraft. In some cases, careful attention to detail will allow specific elements of the overall loss to be reduced with immediate benefit for the mission performance of the aircraft. When considering items of equipment that affect the engine, it is important to understand the effect these will have on overall aircraft performance to ensure that mission capability is not unduly compromised.
Standard

Helicopter Power Assurance

1997-06-01
CURRENT
AIR4083A
This SAE Aerospace Information Report (AIR) defines helicopter turboshaft engine power assurance theory and methods. Several inflight power assurance example procedures are presented. These procedures vary from a very simple method used on some normal category civil helicopters, to the more complex methods involving trend monitoring and rolling average techniques. The latter method can be used by small operators but is generally better suited to the larger operator with computerized maintenance record capability.
Standard

Twin Engine Helicopter Power Requirements

1997-06-01
CURRENT
AIR1850A
This SAE Aerospace Information Report (AIR) defines the power spectrum during normal and emergency operations of a twin engine helicopter and thereby postulates suitable power plant rating structures. This document does not address the power requirements for single engine helicopters or those with more than two engines.
Standard

Substantiation of Power Available and Inlet Distortion Compliance for Rotorcraft Inlet Barrier Filter Installations

2017-03-20
WIP
ARP6912
This Aerospace Recommended Practice (ARP) identifies and defines methods of compliance to power available and inlet distortion requirements for rotorcraft with Inlet Barrier Filter (IBF) installations. The advisory material developed therein may be used as acceptable methods of compliance for determining power assurance, establishing power available, and for substantiating acceptable engine inlet distortion for IBF installations. It is agreed to treat dust, ice, salt water & snow as contaminants to IBF for the purpose of establishing power available and distortion. Flight in known icing will be addressed in ARP6901.
Standard

Helicopter Engine-Rotor System Compatibility

1997-05-01
CURRENT
ARP704A
This SAE Aerospace Recommended Practice (ARP) recommends a methodology to be used for the design, analysis and test evaluation of modern helicopter gas turbine propulsion system stability and transient response characteristics. This methodology utilizes the computational power of modern digital computers to more thoroughly analyze, simulate and bench-test the helicopter engine/rotor system speed control loop over the flight envelope. This up-front work results in significantly less effort expended during flight test and delivers a more effective system into service. The methodology presented herein is recommended for modern digital electronic propulsion control systems and also for traditional analog and hydromechanical systems.
Standard

Helicopter FUEL Economy Evaluation

1978-02-01
CURRENT
AS1516
The purpose of this standard is to provide a method of evaluating helicopter fuel economy which accounts for the significant technical variables in helicopter and powerplant design.
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