This paper explains why a spark ignited gasoline engine, intake pressurized with three cascaded stages of turbocharging, was selected to power NASA's contemplated next generation of high altitude atmospheric science aircraft. Beginning with the most urgent science needs (the atmospheric sampling mission) and tracing through the mission requirements which dictate the unique flight regime in which this aircraft has to operate (subsonic flight at greater then 80 kft) we briefly explore the physical problems and constraints, the available technology options and the cost drivers associated with developing a viable propulsion system for this highly specialized aircraft. The paper presents the two available options (the turbojet and the turbocharged spark ignited engine) which are discussed and compared in the context of the flight regime. We then show how the unique nature of the sampling mission, coupled with the economic considerations pursuant to aero engine development, point to the spark ignited engine as the only cost effective solution available. Surprisingly, this solution compares favorably with the turbojet in the flight regime of interest. Finally, some remarks are made about NASA's present state of development, and future plans to flight demonstrate the three stage turbocharged powerplant.


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    Titel :

    Propulsion System for Very High Altitude Subsonic Unmanned Aircraft


    Beteiligte:
    Bents, David J. (Autor:in) / Mockler, Ted (Autor:in) / Maldonado, Jaime (Autor:in) / Harp, James L., Jr. (Autor:in) / King, Joseph F. (Autor:in) / Schmitz, Paul C. (Autor:in)

    Kongress:

    Aerospace Power Systems 1998 ; 1998 ; Williamsburg, VA, United States


    Erscheinungsdatum :

    1998-04-01


    Medientyp :

    Sonstige


    Format :

    Keine Angabe


    Sprache :

    Englisch




    Propulsion System for Very High Altitude Subsonic Unmanned Aircraft

    D. J. Bents / T. Mockler / J. Maldonado et al. | NTIS | 1998


    Propulsion System for Very High Altitude Subsonic Unmanned Aircraft

    Bents, D. J. / Mockler, T. / Maldonado, J. et al. | British Library Conference Proceedings | 1998


    Propulsion System for Very High Altitude Subsonic Unmanned Aircraft

    Bents, David J. / Maldonado, Jaime / Harp, James L. et al. | SAE Technical Papers | 1998


    Possibilities for very high altitude subsonic propulsion

    Gallington, Roger / Schoenung, Susan / Papadales, Basil | AIAA | 1994


    Possibilities For Very High Altitude Subsonic Propulsion

    Gallington, R. / Schoenung, S. / Papadales, B. et al. | British Library Conference Proceedings | 1994