SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS
A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 43, ISSUE 18 - SEPTEMBER 09, 2005
05 AIRCRAFT DESIGN, TESTING AND PERFORMANCE - PART III
Includes all stages of design of aircraft and aircraft structures and systems.
Also includes aircraft testing, performance, and evaluation, and aircraft and flight simulation technology.
For related information see also 18 Spacecraft Design, Testing and Performance; and 39 Structural Mechanics.
For land transportation vehicles see 85 Technology Utilization and Surface Transportation.
20050209980 Flight Test Squadron (0452nd), Edwards AFB, CA, USA
Reliability and Maintainability, Chapter 22
Howell, Jan M.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 22-1 - 22-9; In English; See also 20050209967; Copyright; Avail: CASI; A02, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
The purpose of this Section is to provide an overview of reliability and maintainability (R&M) evaluations conducted during initial flight test.
For purposes of this Section reliability is defined as the probability that an item will perform its intended function for a specified interval under stated conditions. Maintainability is a characteristic of design and installation which is expressed as the probability that an item will be retained in or restored to a specified condition within a given period of time, when maintenance is performed in accordance with prescribed procedures and resources.
Flight test R&M evaluations are essential because R&M characteristics cannot be predicted with any degree of success. Initial reliability for newly designed equipment, during bench and laboratory testing, is normally 10 to 20 percent of the predicted value. Considerable laboratory and flight test is required before the actual reliability begins to approach the original prediction. Therefore, it is essential that the R&M engineer be involved during the design and early production stages. Otherwise the improvement in R&M during the flight test phase may be insufficient to obtain the desired minimum R&M level without initiating a new design and production schedule.
The R&M engineer faces a constant battle to justify his evaluation. It obviously takes time and costs money to run the complete R&M evaluation but the results of a good evaluation may not really be evident until the aircraft is in service use. He must be prepared to utilize data from prototype system and bench tests to provide indicators of potential problem areas and/or validate good characteristics. This Section will concentrate on the flight test portion of the R&M process. However, there are many activities such as ground laboratory and bench tests, studies, maintainability demonstrations, etc., that constitute invaluable portions of this overall evaluation that cannot be ignored and must be considered/utilized when establishing the flight test program. Author
Flight Tests; Performance Tests; Reliability; Maintainability; Data Systems
20050209983 Sparta, Inc., Lancaster, CA, USA
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Electromagnetic Interference/Electromagnetic Compatibility, Chapter 27
Borek, Robert W.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 27-1 - 27-16; In English; See also 20050209967; Copyright; Avail: CASI; A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Ideally, Electromagnetic Interference/Electromagnetic Compatibility (EMI/EMC) testing should have been completed before an aircraft makes its initial flight. However, it is almost inevitable that problems will occur during the ensuing flight test program. Moreover, the Flight Test Engineer (FTE) will be involved in the ground testing of the aircraft. This Section provides some background information on EMI/EMC for the novice FTE involved in these disciplines. Furthermore, it identifies some of the standards and specifications used for developing test objectives and procedures for EMI testing. The discussions are based primarily on existing military requirements. This was done with the supposition that industrial and commercial specifications may vary from country to country, whereas the referenced military documents are uniformly related and generally obtainable. However, the one exception is a set of civil standards that are used all over the world. These standards are continually updated and thoroughly address the EMI conditions to which civil aircraft are subjected. [27-1] Further, this Section describes the major sources of EMI and the broad range of system-subsystem EMI/EMC testing, typical test equipment, and the facilities generally used. In addition, some basic EMI precautions to be taken in designing aircraft and instrumentation systems are discussed. Author
Electromagnetic Compatibility; Electromagnetic Interference; Ground Tests; Flight Tests; Accident Prevention
20050209984 Air Force Flight Test Center, Edwards AFB, CA, USA
Future Trends, Chapter 30
Hildebrand, R. R.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 30-1 - 30-4; In English; See also 20050209967; Copyright; Avail: CASI; A01, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
The world of the Flight Test Engineer (FTE) has always been one of change. Looking back, the Wright Brothers’ first flight in 1903 did not have a test range (although they did measure the distance flown - probably with a surveyor’s chain -and took documentary pictures) nor did they have any special flight test instrumentation. Up until the first supersonic flight in 1947, there was little call for aircraft range support or for special instrumentation - the instrumentation system was notes on a pilot’s or engineer’s knee-board, or photographs of the pilot’s panel or a duplicate set of the pilot’s instruments. However, with the rapidly growing capability and complexity of the test aircraft, it was now necessary to provide an ‘automated’ means of acquiring the data that was changing too fast for the pilot to record it and consequently, photo-observer panels and/or oscillographic recorders became common. The advent of missiles required the development of telemetry and accurate real-time Time-Space-Position Information (TSPI). With the advent of the ‘X’ type aircraft and their high risk missions, the use of telemetry to provide pilot advisory information, assist in flight safety, and to assure that data were obtained became commonplace. The introduction of tape systems, computers, and miniaturized components also drove the need for more sophistication in the range - acquiring telemetry data in ever increasing quantities, rates, and accuracy, using space positioning instrumentation to provide TSPI rather than just providing pointing or air traffic control, etc. The advent of large missiles and space flight required another large step in the complexity and quantity of instrumentation and expanded range capability. Author
Flight Safety; Air Traffýc Control; Real Time Operation; Pilot Support Systems; Pointing Control Systems; Flight Test Instruments; Engineers; Flight Tests
20050209986 Aeroplane and Armament Experimental Establishment, Boscombe Down, UK
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Background Considerations, Chapter 3
Appleford, J. K.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 3-1 - 3-7; In English; See also 20050209967; Copyright; Avail: CASI; A02, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Before describing (in Sections 4 to 10) the many preparatory activities involved in flight testing, it is appropriate to introduce here some general background considerations which bear on the Flight Test Engineer’s (FTE’s) task. Clearly, most of the FTE’s concern is with technical matters and, if the trials are to be conducted in a safe, efficient and economic manner, he must obtain (and consider carefully) the types of technical data discussed in paragraph 3.3 below. However, there are also wider issues of which he must be aware. All flight testing is instigated at the request of some form of ‘sponsor’ or ‘customer’, whose stated requirements, priorities and timescales the FTE must always endeavour to satisfy. Yet the FTE’s freedom of action to formulate and conduct a successful test programme will depend on such factors as his relationship with that customer, the customer’s overall programme, the resources available for the tests and the ‘rules’ of the FTE’s organisation. In keeping with the aims of this volume, this Section offers an outline of some of these wider organisational and programme issues which may affect the FTE’s freedom to define and control the flight test programme. Derived from text
Flight Tests; Engineers; Economics
20050209988 Naval Air Warfare Center, Patuxent River, MD, USA
Logistics Support Considerations, Chapter 5
Kolwey, Herman G.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 5-1 - 5-4; In English; See also 20050209967; Copyright; Avail: CASI; A01, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
When preparing for the conduct of a Test and Evaluation (T&E) program it is vital that the Flight Test Engineer (FTE) ensure that adequate arrangements are being made for the logistics support of the test program. The FTE must understand the type of tests that will be conducted and then communicate the peculiar needs of his test project to the logistics support community. Logistics support is required to keep the test aircraft flying in the required test configuration, while a logistics test evaluates the support system required for the intended user to operate the aircraft. The logistic support system includes support equipment, technical orders, facilities, and manning. Test support requirements may vary drastically depending on status of the aircraft (new aircraft such as C-17, or old aircraft such as F-14D), environmental conditions (cold/hot, salt water/sand, electromagnetic environment, altitude, aircraft carrier, etc.), or repetitive nature of the test (takeoff/landing, accelerations/decelerations, or repetitive high time at specific test conditions). Perhaps the most important point to make is that the FTE should locate the logistics experts at their facility, explain the tests that are to be conducted, and task them to provide the support that is required. The FTE cannot arrange the logistics support without expert help. However, these logistics experts may well be able to provide information on spares, training and timing of support so that the FTE can rearrange his planned schedule of tests more efficiently to better match the availability of support. This Section will provide an overview of the types of logistic planning that must be conducted in preparation for such tests and the role of the FTE in defining these support requirements. The conduct of the Logistics T&E program is discussed in Section 23. Derived from text
Logistics Management; Flight Tests; System Effectiveness; Support Systems; Test Facilities; Schedules
20050209992 Air Force Flight Test Center, Edwards AFB, CA, USA
Pre-Flight Tests, Chapter 9
Kirsten, Paul W.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 9-1 - 9-22; In English; See also 20050209967; Copyright; Avail: CASI; A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Measure and evaluate the characteristics of an aircraft in a non-flying environment and to verify that these characteristics are as desired. Since aircraft systems are becoming more and more complex, conducting proper pre-flight testing to help identify system characteristics and deficiencies prior to flight is more important now than ever before. Much flight test time has been lost fixing problems that should have been found and corrected prior to flight. Accidents have occurred because pre-flight tests and verification procedures were not conducted thoroughly enough to identify the aircraft’s characteristics properly or to find system discrepancies. Proper pre-flight testing helps ensure that the aircraft is ready to fly and contributes toward an efficient, productive, and safe flight test program. The reader should be aware that this Section is dedicated to the testing that should take place prior to the first flight. There are other ‘pre-flight’ tests that take place prior to each individual flight. These latter tests are not discussed in this Section. The following paragraphs of this Section describe significant tests that are usually accomplished prior to flying a new or highly modified aircraft. Test objectives, descriptions, products, and requirements are provided in the following subsections: 9.1 Wind tunnel tests. 9.2 Simulation tests. 9.3 Propulsion tests. 9.4 Weight and balance tests. 9.5 Ground vibration tests. 9.6 Structural loads tests. 9.7 Gain margin tests. 9.8 Verification and calibration tests. 9.9 Taxi tests. The specific examples given and the test facilities mentioned in this Section will illustrate the approach taken and the techniques used by the US Air Force; however, they are typical of those used by other test organizations. Author
Test Facilities; Vibration Tests; Wind Tunnel Tests; Ground Tests
20050209993 Naval Air Warfare Center, Patuxent River, MD, USA
Preparation of the Flight Test Plan, Chapter 8
Harney, Ronald J.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 8-1 - 8-9; In English; See also 20050209967; Copyright; Avail: CASI; A02, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Test plans are written for all aspects of airplane testing such as airframe structural tests, flying qualities and performance tests, avionics tests, simulator validation, systems software tests, and engine tests. It is a written document of the duties and responsibilities of those concerned with planning and conducting assigned projects. Thorough and timely reviews of the test plan can aid in ensuring that the test is conducted safely. All members of the test team should be familiar with the test plan prior to conducting test flights. The knowledge gained from previous tests similar to the tests to be conducted is always of importance. References to previous reports, discussions with experienced test teams, and reference to any flight safety data bases should be included. This Section provides guidance to the Flight Test Engineer regarding the type of information that should be included in the test plan. The following paragraphs are typical of comprehensive test plans. [8-1] It should be noted that some organizations separate documentation of safety planning, definition of instrumentation, etc., but all of these elements must be included in the totality of the test preparation documentation. There are some significant differences in the planning tests for commercial aircraft. Some of these differences are noted in paragraph 8.3. Derived from text
Flight Tests; Performance Tests; Avionics; Computer Systems Programs; Engine Tests; Data Bases; Flight Characteristics
20050209995 Naval Test Pilot School, Patuxent River, MD, USA
Rotorcraft Flight Envelope Unique Considerations, Chapter 12A
Mosher, MichaelW.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 12A-1 - 12A-10; In English; See also 20050209967; Copyright; Avail: CASI; A02, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
As noted in Section 12, the term flight envelope is used to refer to the boundaries of aircraft loading and flight conditions within which operation of the aircraft is satisfactory, and beyond which some aspect becomes unacceptable. Each aircraft has its own peculiar set of operating conditions and limitations, and this is particularly true of rotorcraft. In addition to the concerns of the fixed wing aircraft test engineer, the helicopter test engineer has to be concerned with dynamic components such as main and tail rotors and their associated control components, transmissions, noise, vibrations, and environmental factors such as swirling particulates which can cause visual obscuration and/or aircraft erosion when operating in unprepared areas like desert, snow, or over salt water. Operation in the hover/low speed regime is a unique capability and is therefore the forte of the helicopter. This ‘new’ regime has its own envelope concerns. This Section provides a brief overview of some of the considerations when establishing/expanding the flight envelope of a rotorcraft. Types of tests and maneuvers, instrumentation, and special considerations will be discussed. However, the reader must be aware that this Section is far from a complete description of all the factors which must be considered in establishing a rotorcraft flight envelope. Much of the material presented in Section 12 is pertinent to rotorcraft envelope definition. Derived from text
Flight Conditions; Flight Envelopes; Aircraft Configurations; Rotary Wing Aircraft
20050209996 Naval Air Warfare Center, Patuxent River, MD, USA
Logistics Test and Evaluation, Chapter 23
Baxley, Frank W.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 23-1 - 23-9; In English; See also 20050209967; Copyright; Avail: CASI; A02, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
The Test and Evaluation (T&E) of logistics is a measurement of the support system’s ability to meet predetermined performance requirements. Each element of logistics is equally important and must be given consideration for logistics T&E. Not all elements are applicable to every program acquisition due to the nature of the equipment being procured and subsequently tested. Care must be exercised to ensure that the impacted elements are included in the Logistics T&E process. In addition to the above elements the logistics T&E process must also integrate the Reliability and Maintainability (R&M) process and the Human Factors (HF) evaluation. Note that the equipment’s R&M design features have a great influence over the efficiency of the support system. For example, if the support system is developed concurrent with equipment design and an R or M design feature fails to meet the predicted level of performance, the equipment must be redesigned or modifications must be made to the effected logistics element to compensate for the failed design feature. Therefore, the developer of the support system performance requirements must be thoroughly knowledgeable of the R&M design requirements, the predicted performance, and achieved capabilities. Derived from text
Evaluation; Logistics; Support Systems; Human Factors Engineering
20050209997 Vleghert, J. P. K., Badhoevedorp, Netherlands
Performance, Chapter 13
Vleghert, J. P. K.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 13-1 - 13-14; In English; See also 20050209967; Copyright; Avail: CASI; A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
This Section will set forth the types of tests, procedures, instrumentation requirements, data analysis and presentation, and the purposes for conducting performance tests. In general, performance tests are conducted to: 1) Determine those elements of the aircraft’s performance which are critical from flight safety considerations, i.e., the weight/altitude/temperature limits at which the applicable performance requirements with respect to the take-off and landing distances and climb gradients are met; 2) Acquire data to quantify the capabilities of an aircraft, to verify and/or establish the aircraft’s performance model, and to provide information for the Aircraft Operation Manual (AOM); and 3) Determine if an aircraft meets specifications/guarantees. There are a number of sources of detailed information on conducting performance tests, and analyzing and presenting data. A few of these sources are listed as references and a selected few are contained as bibliographic entries. [13-1, 13-2, 13-3] This Section offers a broad introduction to the topic: although based principally on typical civil practice, a similar approach is applied to military aircraft, and aspects specific to military aircraft, such as combat, are covered. Derived from text
Performance Prediction; Performance Tests; Climbing Flight; Flight Safety; Takeoff
20050209999 Aeroplane and Armament Experimental Establishment, Boscombe Down, UK
Airframe Tests, Chapter 17
Appleford, J. K.; Introduction to Flight Test Engineering, Volume 14; July 2005, pp. 17-1 - 17-37; In English; See also 20050209967; Copyright; Avail: CASI; A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
This Section outlines the flight testing required to demonstrate that each of the systems installed in an aircraft is suitable for its operational role(s). It is primarily written from the perspective of a military Flight Test Engineer (FTE) but most of the contents are applicable to civil aircraft. Reflecting the introductory nature of this Volume, its scope is limited to systems normally found in all aircraft, e.g., fuel, hydraulic, electrical, etc., systems. The tests described below are usually made under the prevailing ambient conditions and, to assess behaviour under climatic extremes and in all weathers, further testing is conducted as described in Section 18. Tests of the propulsion system are covered separately in Section 23, but for systems associated with specific roles the reader should consult appropriate specialized sources. Derived from text
Airframes; Flight Tests; Ambience
Source: NASA.
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