Engineering topics

Wickenheiser, T. J.

Publications and source records attributed to Wickenheiser, T. J..

3 records

NASA NTRS1991

Performance impact on nuclear thermal propulsion of piloted Mars missions with short transit times

The requirements of nuclear thermal propulsion (NTP) are examined with respect to a specific mission scenario derived from Stafford Committee recommendations. The recommended mission scenario is a split/sprint opposition mission which includes a piloted vehicle and a cargo vehicle, and the baseline mission is developed from a reference trajectory. Key mision parameters are developed from the baseline mission, including engine-thrust levels, mission opportunity, and engine burn-time requirements. The impact of engine failure is also considered in terms of burn-time requirements, and other mission-performance issues considered include propulsion-technology assumptions, triple-perigee earth-departure burns, and Mars parking-orbit selection. The engine requirements call for a 50-75-klb engine-thrust level, maximum single burn time of 0.6 hours, and a maximum total-mission burn time of 1.7 hours. For a crew of 6, a 475-day total-mission trip with a 90-day stay at Mars is possible.

Wickenheiser, T. J.↗

NASA NTRS1983

Propeller performance and weight predictions appended to the Navy/NASA engine program

The Navy/NASA Engine Performance (NNEP) is a general purpose computer program currently employed by government, industry and university personnel to simulate the thermodynamic cycles of turbine engines. NNEP is a modular program which has the ability to evaluate the performance of an arbitrary engine configuration defined by the user. In 1979, a program to calculate engine weight (WATE-2) was developed by Boeing's Military Division under NASA contract. This program uses a preliminary design approach to determine engine weights and dimensions. Because the thermodynamic and configuration information required by the weight code was available in NNEP, the weight code was appended to NNEP. Due to increased emphasis on fuel economy, a renewed interest has developed in propellers. This report describes the modifications developed by NASA to both NNEP and WATE-2 to determine the performance, weight and dimensions of propellers and the corresponding gearbox. The propeller performance model has three options, two of which are based on propeller map interpolation. Propeller and gearbox weights are obtained from empirical equations which may easily be modified by the user.

Plencner, R. M.↗

NASA NTRS1980

Comparisons of four alternative powerplant types for future general aviation aircraft

Recently completed NASA sponsored conceptual studies were culminated in the identification of promising new technologies for future spark ignition, diesel, rotary, and turbine engines. The results of a NASA in-house preliminary assessment study that compares these four powerplants types in several general aviation applications are reported. The evaluation consisted of installing each powerplant type in rubberized aircraft which are sized to accomplish fixed missions. The primary evaluation criteria include projected aircraft cost, total ownership cost, and mission fuel.

Wickenheiser, T. J.↗