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This paper discusses the importance of enroute wind conditions and the need for a wind measurement system which provides accurate and timely observations of wind and temperature conditions aloft. Recent advances in remote measurement of winds, temperature, and humidity such as the Stratospheric-Tropospheric radars and profilers developed at the National Oceanic and Atmospheric Administration’s Environmental Research Lab form the basis of such a system. A domestic system could and should be established using these devices together with a near real time winds aloft data dissemination network. Estimates of the saving in aircraft fuel consumption benefits range from 1 to 3 percent per year, or from $ 100 to $ 300 million for U.S. aviation system users at current prices and consumption.

This document recommends supplementary design criteria to enhance endurance and reliability of transport aircraft wheels and brakes.

This document recommends supplementary design criteria to enhance endurance and reliability of transport aircraft wheels and brakes.

This document recommends supplementary design criteria to enhance endurance and reliability of transport aircraft wheels and brakes.

Unmanned Aerial Vehicles (UAV) are being deployed in military, law enforcement, search & rescue, scientific research, environmental & climate studies, reconnaissance and other commercial and non-commercial applications on a large scale. A design and development of landing gear system has been taken up for a UAV. This paper presents the design optimization of structural components of Wheel-Brake & Fork assembly pertaining to the Main Landing Gear (MLG) for a UAV. The wheel, fork, axle and brake unit constitute the wheel assembly. The wheel-brake assembly is assembled with the strut assembly and forms the Landing gear system. The Fork is the connecting member between the shock strut and the axle containing the wheel-brake assembly. As the fork and axle are subjected to shock loads while landing, the strength of these components are very much essential to withstand the dynamic loads.

Premature wearout of augmentor hydraulic fuel pumps was being experienced in service on a fighter aircraft engine. The removal times ranged from 150 to 800 engine operating hours. Considerable effort had gone into the understanding of the physics of failure and overcoming this problem in a modified pump. However, there still remained the question of how best to proof test the new pump. The challenge was to demonstrate that the redesigned pump was significantly better than the old pump. The problems faced during design verification will be discussed in this case study. For example, does an accelerated test duplicate the service failure mode? When has an accelerated test run long enough to prove the redesign is in fact better than the old product? This paper illustrates the application of new technology to solve these research and development program problems through the use of Weibull and Weibayes Analysis.

This document establishes the minimum requirements for an environmental test chamber, and test procedures to carry out anti-icing performance tests according to the current materials specification for aircraft deicing/anti-icing fluids. The primary purpose for such a test method is to determine the anti-icing endurance under controlled laboratory conditions of AMS1424 Type I and AMS1428 Type II, III, and IV.

Through microscopic visualization experiments, a process generally known as depth filtration was shown to be caused by surface pores. Moreover, the existence of a soot cake layer was an important advantage for filtration performance because it could trap most of the particulates. We proposed an ideal diesel particulate filter (DPF), in which a silicon carbide (SiC) nanoparticle membrane (made from a mixture of 80 nm and 500 nm powders) instead of a soot cake was sintered on the DPF wall surface; this improved the filtration performance at the beginning of the trapping process and reduced energy consumption during the regeneration process. The proposed filter was called a diesel particulate membrane filter (DPMF). A diesel fuel lamp was used in the trapping process to verify the trapping and oxidation mechanisms of ultrafine particulate matter. Thus, the filtration performance of the membrane filters was shown to be better than that of conventional DPFs.

Verification of landing gear design strength is accomplished by dynamic and static test programs. This is essentially a verification of the analytical procedures used to design the gear. An industry survey was recently conducted to determine just what analysis and testing are currently being applied to landing gear. Timing in relation to first flight of new aircraft was also questioned. Opinions were solicited from designers of the following categories and/or types of aircraft: a Military - Large Land Based (Bomber) b Military - Small Land Based (Fighter) c Military - Carrier Based (Navy) d Military - Helicopter (Large) e Military - Helicopter (Small-attack) f Commercial - Large (Airliner) g Commercial - Small (Business) h USAF (WPAFB) - Recommendations It is the objective of this AIR to present a summary of these responses. It is hoped that this summary will be useful to designers as a guide and/or check list in establishing criteria for landing gear analysis and test.

The ARP shall cover the objectives and activities of Verification & Vallidation Processes required to assure high quality and/or criticality level of an IVHM Systems and Software.

A method is presented whereby, using the predicted spectrum of lunar soil properties in terms of the land locomotion soil value system, the performance of various vehicle configurations are analyzed. From this analysis the mission success probability may be calculated from the standpoint of vehicle immobilization, fuel consumption, torque requirements, inability to climb the required slopes, or any other desired parameter.

This SAE Aerospace Standard (AS) provides the general performance, design, installation, test, development, and quality assurance requirements for the flight control related functions of the Vehicle Management Systems (VMS) of military piloted aircraft. It also provides specification guidance for the flight control interfaces with other systems and subsystems of the aircraft.

The development of exhaust nozzles and their application in operational military aircraft are discussed. Prime consideration is given to installation factors such as engine bay and nozzle cooling, inlet-engine flow matching, and aerodynamic effects on external afterbody drag. Examples of various operational exhaust systems are given which show how the aircraft-exhaust nozzle characteristics are integrated to achieve maximum system compatibility and performance. Results from one flight test program are presented which show how an aircraft-exhaust nozzle system was integrated to achieve maximum installed performance.

Variable cycle engines (VCEs) hold promise as an enabling technology for supersonic business jet (SBJ) applications. Fuel consumption can potentially be minimized by modulating the engine cycle between the subsonic and supersonic phases of flight. The additional flexibility may also contribute toward meeting takeoff and landing noise and emissions requirements. Several different concepts have been and are currently being investigated to achieve variable cycle operation. The core-driven fan stage (CDFS) variable cycle engine is perhaps the most mature concept since an engine of this type flew in the USAF Advanced Tactical Fighter prototype program in the 1990s. Therefore, this type of VCE is of particular interest for potential commercial application. To investigate the potential benefits of a CDFS variable cycle engine, a parametric model is developed using the NASA Numerical Propulsion System Simulation (NPSS).

Variable Cycle Engines being studied for advanced commercial supersonic transports show potential for significant environmental and economic improvements relative to 1st generation SST engines. The two most promising concepts are: a Variable Stream Control Engine and a Variable Cycle Engine with a rear flow-control valve. Each concept utilizes variable components and separate burners to provide independent temperature and velocity control for two coannular flow streams. Unique fuel control techniques are combined with cycle characteristics that provide low fuel consumption, similar to a turbojet engine, for supersonic operation. This is accomplished while retaining the good subsonic performance features of a turbofan engine. A two-stream coannular nozzle shows potential to reduce jet noise to below FAR Part 36 without suppressors. Advanced burner concepts have the potential for significant reductions in exhaust emissions.

This paper traces the historical development of the BICERI variable compression ratio piston and its use in a number of engines. In early petrol experiments a variable compression piston covering the range from 6.5:1 to 16.5:1 showed significant efficiency improvements on 70 octane petrol. In the diesel engine field, Teledyne Continental increased the power of a V12 direct injection tank engine from 550 hp (30 hp per litre) to 1475hp (80 hp per litre) retaining the original crankcase and structure. At BICERI the output of a supercharged research engine was increased to 40 bar bmep with a peak cylinder pressure of only 165 bar. Military application lapsed with the preference for gas turbine engines, but the time is now right to explore the capabilities of variable compression within the wider automotive scene. Volkswagen have been working on a variable compression engine and have shown fuel consumption improvements up to 13% together with lower emissions.

THIS paper represents an attempt to illustrate the values of octane-number improvements in aviation gasolines in terms of increased earning power of current-type transport airplanes when proper provisions have been made in the original designs. The procedure consists in computing the change in earning power of a gallon of gasoline when octane-number changes are reflected in altered fuel consumptions or take-off load capacities.

This SAE Aerospace Recommended Practice (ARP) provides a process for the verification and validation of monitors used in highly-integrated and complex aircraft flight control and related systems.

Individual pressure vessel (IPV) nickel-hydrogen technology was advanced at NASA Lewis and under Lewis contracts with the intention of improving cycle life and performance. One advancement was to use 26 percent potassium hydroxide (KOH) electrolyte to improve cycle life. Another advancement was to modify the state-of-the-art cell design to eliminate identified failure modes. The modified design is referred to as the advanced design. A breakthrough in the Low-Earth-Orbit (LEO) cycle life of IPV nickel-hydrogen cells has been previously reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40 000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. The boiler plate test results are in the process of being validated using flight hardware and real time LEO test at the Naval Weapons Support Center (NWSC), Crane, Indiana under a NASA Lewis Contract. An advanced 125 Ah IPV nickel-hydrogen cell was designed.

The United States Navy F/A-18 aircraft uses two 30/40 KVA generating systems to provide precise 400 Hz power to their respective isolated busses. Each generating system is composed of a six phase generator running at a speed proportional to engine rpm, feeding an SCR-based, naturally commutated cycloconverter. This was the first integral package with shared cooling oil, production, 400 Hz VSCF system. Over 2,000 units have been produced to date. Due to the radical shift from historical, mechanically supplied constant speed technology, the F/A-18 VSCF design initially raised numerous reliability questions. This paper serves to address those concerns and provide development questions with historical field performance/analyses in response. Reliability predictions using MIL-HDBK-217 procedures are compared to Navy 3-M field performance data over the last eight year production period.