Engineering topics

Sievers, G. K.

Publications and source records attributed to Sievers, G. K..

8 records

NASA NTRS1984

Fuel savings potential of the NASA Advanced Turboprop Program

The NASA Advanced Turboprop (ATP) Program is directed at developing new technology for highly loaded, multibladed propellers for use at Mach 0.65 to 0.85 and at altitudes compatible with the air transport system requirements. Advanced turboprop engines offer the potential of 15 to 30 percent savings in aircraft block fuel relative to advanced turbofan engines (50 to 60 percent savings over today's turbofan fleet). The concept, propulsive efficiency gains, block fuel savings and other benefits, and the program objectives through a systems approach are described. Current program status and major accomplishments in both single rotation and counter rotation propeller technology are addressed. The overall program from scale model wind tunnel tests to large scale flight tests on testbed aircraft is discussed.

Whitlow, J. B., Jr.↗

NASA NTRS1980

Summary of NASA QCGAT program

The application of large turbofan engine technology to small general aviation turbofan engines to achieve low noise, low emissions, and acceptable fuel consumption is described.

Sievers, G. K.↗

NASA NTRS1979

Preliminary QCGAT program test results

The paper presents the NASA Lewis program to demonstrate that large engine technology can be applied to general aviation engines to reduce noise, emissions, and fuel consumption. After a Phase I study, two contractors, Garrett AiResearch and AVCO-Lycoming, were selected to design, manufacture, assemble, test, and deliver their Quiet, Clean, General Aviation Turbofan (QCGAT) engines to NASA. Noise, emission, and performance goals and how well they were met are discussed. Noise goals involve take off noise 3.5 n. mi. from runway threshold, sideline noise at .25 n mi. and approach noise 1 n mi. from the runway at an altitude of 370 ft. The AiResearch engines power a stretched Learjet 35 and the Lycoming a specially conceived Beech executive jet, resulting in differing power goals. Thus the thrust goal for the Lycoming was 1622 lb. while the AiResearch goal was 3937 lb. Cruise thrust goals were 485 lb. at Mach 0.6 at 25,000 ft. and 903 lb. at Mach 0.8 at 40,000 ft. respectively. The design of both engines, based on existing cores, is studied, noting such special QCGAT features as new reduction gears, combustor and power turbine. Test results are given, indicating that while the goals for noise and thrust were met those for emissions were only partially met.

Koenig, R. W.↗

NASA NTRS1979

NASA research on general aviation power plants

Research activities within NASA to support general aviation industry in improving propulsion engines are described. Near-term objectives include improvements of gasoline piston engines to achieve fuel savings and reduce emissions well below EPA levels. To meet the longer term goals, advanced combustion research has been considered as essential in obtaining further improvements in BSFC (break specific fuel consumption). Modifications of an aircraft rotary engine were tested and it was found that by increasing the compression ratio and other refinements the BSFC was improved by 15%. The applicability of available large turbofan engine technology to small engines in order to obtain significant reductions in noise and pollutant emissions is being tested. Studies have been conducted at exploring the possibility of achieving high improvements in cost and performance for turboprop engines of less than 1000 horsepower.

Stewart, W. L.↗

NASA NTRS1979

Preliminary QCGAT program test results

NASA Lewis Research Center is conducting a program to demonstrate that large commercial engine technology can be applied to general aviation engines to reduce noise, emissions and fuel consumption and to develop new technology where required. The overall engine program, design, and technology incorporated into the QCGAT engines are described. In addition, preliminary engine test results are presented and compared to the technical requirements the engines were designed to meet.

Koenig, R. W.↗

NASA NTRS1978

NASA Research on General Aviation Power Plants

Propulsion systems are key factors in the design and performance of general aviation airplanes. NASA research programs that are intended to support improvements in these engines are described. Reciprocating engines are by far the most numerous powerplants in the aviation fleet; near-term efforts are being made to lower their fuel consumption and emissions. Longer-term work includes advanced alternatives, such as rotary and lightweight diesel engines. Work is underway on improved turbofans and turboprops.

Stewart, W. L.↗

NASA NTRS1977

NASA Quiet, Clean General Aviation Turbofan /QCGAT/ program status

Emissions pollution studies, noise studies, and engine performance studies and their place in QCGAT developmental program status are reported. The Lycoming TFE 731 turbofan engine, the GE T700-GE-700 high bypass ratio turbofan, and the AVCO-Lycoming LTS 101 turboshaft engine are prominent candidates in the tests for urban quiet turbofan service. Two phases in the program are characterized. Engine quieting, polluting emissions abatement, and fuel economies are particularly important for the anticipated rise in number of jet propulsion craft using smaller airports adjacent to communities accustomed to low noise/pollution backgrounds.

Bresnahan, D. L.↗

NASA NTRS1977

NASA Quiet Clean General Aviation Turbofan (QCGAT) program status

The suitability of large engine technology to reduce noise, emissions, and fuel consumption of small turbine engines and develop new technology where required is determined. The design, fabrication, assembly, test, and delivery of the experimental engines to NASA are discussed.

Bresnahan, D. L.↗