Search Results

A study was conducted to demonstrate the ability of a low order panel aerodynamic flow code to predict the aircraft-induced propeller plane flow field and the resulting steady state propeller blade loads for a single-rotation, wing-mounted tractor system. Comparisons between predicted and measured flow field surveys and resulting blade loads, including the first five harmonics, were made for the U.S. Navy P-3C land-based patrol turboprop aircraft. The study showed that low order flow codes accurately model the induced flow field.

This paper presents an overview of design considerations, design development, and maintenance practices required to certify a commercial transport aircraft and ensure continuing airworthiness in operation. Subjects discussed include philosophy and criteria of airworthiness with examples of their application; evolutionary nature of the design development; scope of development testing; and the process involving manufacturer, operator, and regulatory agency to ensure continuing airworthiness throughout the aircraft operational life. Also discussed are the recent revisions in airworthiness regulations, which, along with advances in technology, have resulted in changing trends in the approach to substantiating continuing airworthiness, particularly for structures.

The use of interactive computer graphics for aircraft structural design is discussed. The software used is the Lockheed-California Company Computer-graphics Augmented Design and Manufacturing (CADAM)® system in conjunction with our inhouse Surface Design and Finite Element Model programs. Starting with the conceptual design on the CADAM system, configuration geometry is generated for use by analysis users, preliminary design, loft, and production design organizations. An example used to demonstrate the application of the system is the development of a smaller horizontal tail for L-1011 derivatives, under the sponsorship of the NASA Energy Efficient Transport Technology office. The increased productivity achieved by using the CADAM system is described.

The application of integrated active controls to high performance aircraft has been made feasible by recent advances in active control technology. This paper summarizes some of these advances. One approach to the methodology for synthesizing active control transfer functions is reviewed. Application of this methodology to a supersonic cruise vehicle is discussed. Significant structural weight savings were realized using active controls for this vehicle. Among the several design advantages noted is the ability to avoid expensive redesign of structurally deficient aircraft by means of active controls.

This paper notes the large increase in fuel economy due to the use of the regenerative cycle, particularly at low partial power. It then examines the striking effect of using regenerative turboprop engines on the trade-off between various aspects of patrol aircraft dessign and mission capability.

A new, completely independent monitor (capable of operation through Category IIIc weather condition) for use with automatic landing systems, is undergoing development by Lockheed for possible use in L-1011 aircraft. Following intensive analysis, a Ka band airborne radar was selected to provide pilot confidence through independent monitoring of the L-1011 (1) dual-dual, fail operative, automatic landing system's performance. Lockheed's airborne flying test bed (CV-240) program has so far provided evidence that the Independent Landing Monitor concept has a definite future in commercial automatic landing applications under reduced visibilities. Visual enhancement would improve the acceptability of near zero-zero operation and consequently reduce the number of unnecessary go-arounds.

This paper answers the question: Will the Vertical Takeoff and Landing (VTOL) commercial aircraft be a competitor or an assistant to conventional aircraft? VTOL of the type being studied by the Lockheed-California Co. are designed to compete with conventional commercial aircraft in short range operations. The Lockheed Airline Systems Simulation model was used to investigate this competition. The results for the U. S. Northeast Corridor show that a fully developed VTOL system will assist the airlines by turning short haul operations from a losing to a profitable operation and by offering the passenger better service. Cities will be assited by the amelioration of airport congestion and this, in New York, could obviate the need for construction of at least one additional major conventional airport.

The paper deals with the emerging and topical subject of All-Electric Aircraft in which the electric system in an advanced airplane serves all the functions and services normally supplied by multiple power systems, such as engine bleed air, hydraulics, pneumatics, and conventional type electric power systems. Engine starting is of particular interest because of its demands for special logistic and maintenance ground support. Military and commercial aircraft typically use pneumatic, cartridge, fuel/air (combustion) or monopropellant starting methods, so these must be replaced by electric starting. The trend of the advanced technology engines is towards high bypass and high compression ratios, making them increasingly sensitive to tapping the compressor airflow: The energy-efficient engine is, therefore, an important design consideration in the All-Electric Airplane.

The incentives for re-engining the Lockheed P-3 ASW Patrol aircraft include reduced fuel consumption and therefore reduced operating costs (the P-3 currently accounts for 16 percent of the U.S. Navy's annual aviation fuel bill), increased mission effectiveness in terms of radius of action (ROA) and time on station (TOS) (when needed), increased sales potential/production life, increased service life, and reduced maintenance hours. For these reasons, Lockheed has for several years conducted both Navy-funded and in-house-funded engineering studies to identify the impact on performance and cost of re-engining the P-3 with either a derivative type or an all-new advanced turboprop (ATP) type engine. This paper discusses some of the results of these studies. In particular, the engines examined in these studies are compared from both a performance and installation design standpoint, with aircraft mission performance improvements identified.

Highlights of a study conducted by Lockheed for the National Aeronautics and Space Administration (NASA) are presented. The potential benefits are based on realistic advanced aluminum alloy property goals considering powder metallurgy (PM) and ingot metallurgy (IM) technologies. The property goals were established in consultation with the Aluminum Company of America (Alcoa) to maximize aircraft systems effectiveness of a 1990 in-service (IOC) transport aircraft. The performance and economic benefits of incorporating advanced alloys in these future advanced technology transport aircraft are summarized. Key issues requiring attention in an advanced aluminum alloy and applications technology development are presented.

A non-dimensional parameter is developed and data provided to estimate the required mass penalty to achieve satisfactory interior cabin noise levels for advanced propfan powered aircraft. The cabin noise criterion is 80 dBA which is representative of present-day turbofan-powered aircraft interiors and was used by NASA in a related study. Numerical results are given here for an advanced narrow-body powered by two 10-bladed propfans, cruising at 0.70 and 0.80 Mach number, designated as the ATX-100.

The high equipment investment cost of today's large transport aircraft, the high daily utilization desired or required for profitable operations, and the potential revenue losses associated with service interruptions make it mandatory for the manufacturer to take an active part in the early reduction and correction of service problems. The high investment, not only by the aircraft operators but also by the manufacturer, demands the establishment of a mutual participation team effort for early problem resolution. This paper deals with an aircraft manufacturer's approach to meeting this challenge. It discusses the accumulation and evaluation of service data, the investigations initiated to properly understand the problem, and the management procedures established to assure a safe and speedy problem resolution with a minimum of service interruption. Specific examples are used to illustrate the types of decisions reached.

The maintenance diagnostics problem is becoming more difficult as weapon systems, operational environments, and tactical requirements become more complex. Existing fighter aircraft have achieved greater than 95% built-in test (BIT) capability, but are experiencing high false removal rates due to fault detection/fault isolation (FD/FI> ambiguities. This paper will shows how to reduce the program risk by implementing testability features as front end requirements. Integrated Diagnostics activities are part of the design process to build testability and supportability into the weapon systems. By influencing the hardware/software design early in the program, a large payoff in logistics costs will result in the operational and support phase.

Commercial transport aircraft must be capable of operating worldwide; accordingly, a fuel of uniform and high quality must be available worldwide. Hydrogen is proposed as fuel for advanced design transport aircraft in the era subsequent to 1990 because of the problems of availability and cost forecast for conventional jet fuel derived from petroleum. The result of design studies to evaluate the feasibility, practicability, and potential advantages/disadvantages of using hydrogen as fuel in both subsonic and supersonic transport aircraft are summarized. The design requirements and characteristics of aircraft tank and fuel systems to satisfactorily contain and control liquid hydrogen fuel are described.