Engine Capabilities Research Articles

Multidisciplinary Analysis of a Lifting Body Launch Vehicle

As part of phase 2 of the X-33 Program, NASA selected an integrated lifting body/aerospike engine configuration as the study vehicle for the conceptual analysis of a single-stage-to-orbit reusable launch vehicle. A team at NASA Langley Research Center participated in the screening and evaluation of a number of proposed vehicle configurations in the early phases of the conceptual design process. The performance analyses that supported these studies were conducted to assess the effect of the vehicle's lifting capability, linear aerospike engine, and metallic thermal protection system on the weight and performance of the vehicle. These performance studies were conducted in a multidisciplinary fashion that indirectly linked the trajectory optimization with weight estimation and aerothermal analysis tools. This approach was necessary to develop optimized ascent and entry trajectories that met all vehicle design constraints. Significant improvements in ascent performance were achieved when the vehicle flew a lifting trajectory and varied the engine mixture ratio during flight. Also, a considerable reduction in empty weight was possible by adjusting the total oxidizer-to-fuel and liftoff thrust-to-weight ratios. However, the optimal ascent flight profile had to be altered to ensure that the vehicle could be trimmed in pitch using only the flow diverting capability of the aerospike engine. Likewise, the optimal entry trajectory had to be tailored to meet thermal protection system heating rate and transition constraints while satisfying a crossrange requirement.

A General Rotor Model System for Wind-Tunnel Investigations

A complex rotorcraft model system has been developed for the NASA Langley Research Center and the U.S. Army Air Mobility R&D Laboratory, Langley Directorate, for aerodynamic and acoustic experimental investigations in the NASA Langley V/STOL tunnel. This generalized rotor model system has a powered main rotor, tail rotor, and auxiliary engine capability. It may be configured to represent a variety of rotorcraft configurations. The first investigation was conducted to determine the performance, acoustic, stability, and control characteristics of the NASA/Army Rotor Systems Research Aircraft with an articulated rotor. In a second investigation, a V*-scale AH-1G configuration with a teetering rotor is being represented to determine if a V-tail will improve the directional characteristics. Future programs are planned to investigate advanced rotor blade airfoils for improved performance and acoustic characteristics.

An Experimental Study on the Performance of a Multifuel Engine : Part 3, An Attempt of M-Combusion Applied to a Swirl Chamber

By the adoption of M-combustion process proposed by J. S. Meurer, the low rate of pressure rise and smoother running will be assured, because combusion takes place after gradual evaporation of the fuel from the combusion chamber wall. Also, the combusion behaviour of this process is almost the same as the prograssive combusion of pre-mixed mixture, so the combusion completes quickly and better thermal efficiency will be assured. This paper covers an experiment with regard to the attempt of M-combustion applied to a swirl chamber, to improve the multifuel capability of diesel engine. And the effects on the combustibility of the wall temperature, dimensions of the fuel injection system, and engine operating conditions were discussed, and engine performances on gas oil and gasoline were compared. As the result, smoother combustion was assured by the adoption of M-combustion on swirl chamber, and if gasoline was used as fuel, exhaust smoke was reduced over a wide load renge. If this process was applied to direct injection engine such as M. A. N., there will exist a weak point concerning the formation of the combustion air swirl, but if a swirl chamber is used, this problem will be solved perfectly.

Vectored thrust engines for single and multiengined aircraft

Many important advances have been made in recent years in the development of engines for V/STOL aircraft. In this paper, the application of V/STOL power plants currently being developed by Bristol Siddeley Engines is discussed, including the Pegasus vectored thrust engine that has been undergoing bench and flight development in the Hawker P.1127 strike/reconnaissance aircraft for four years and advanced developments designed to power V/STOL strike aircraft. The Pegasus engine is also suited to power V/STOL transport aircraft and the final section of the paper is devoted to this topic. First, the STOL transport aircraft is considered, where the combination of the deflected thrust capability of the Pegasus-type engine with wing/flap boundary-layer control gives extremely short airfield performance. The VTOL transport is then discussed including the development of lightweight lift engines for this application, and finally future vectored thrust engines are considered.

Plymouth butane-electric locomotive : Railway Age, Vol. 99, No. 25

This chapter discusses control of automobile pollution. The principal pollutants that the automobile emits are carbon monoxide (CO), which is a deadly poison; unburned hydrocarbons (HC), which are irritants and sources of smog; and NOx, which is an important link in a chemical chain leading to smog in combination with HC and sunlight. Automobile pollution control is difficult as HC and CO pollution results when the temperatures during combustion are too low, while NOx results when the temperatures are too high. The difficulty with simultaneous control of the pollutants is reflected in the catalysts that might be used to control them. All popular means to control pollutants are very expensive and add considerable complexity to the automobile, confounding both the consumer and repair mechanic and making customer maintenance of the vehicle nearly impossible. Prestratification is a very simple and inexpensive way to control pollution and to increase economy. NOx can be controlled in this manner so that three-way catalysts and electronic carburetion are not required. The prestratification with air is more effective than adding an air pump that delivers air to the exhaust manifold just aft of the exhaust valve. The use of prestratification for pollutant control is currently being applied in combustion control to develop a multifuel engine capability.