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  • AIRCRAFT
  • Aircraft Design, Testing and Performance
  • Inorganic Chemistry
  • 2015-2019  (31)
  • 1950-1954  (33)
  • 1
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    Overcoming the Adoption Barrier to Electric Flight (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Electrically-powered aircraft can enable dramatic increases in efficiency and reliability, reduced emissions, and reduced noise as compared to today's combustion-powered aircraft. This paper describes a novel flight demonstration concept that will enable the benefits of electric propulsion, while keeping the extraordinary convenience and utility of common fuels available at today's airports. A critical gap in airborne electric propulsion research is addressed by accommodating adoption at the integrated aircraft-airport systems level, using a confluence of innovative but proven concepts and technologies in power generation and electricity storage that need to reside only on the airframe. Technical discriminators of this demonstrator concept include (1) a novel, high-efficiency power system that utilizes advanced solid oxide fuel cells originally developed for ultra-long-endurance aircraft, coupled with (2) a high-efficiency, high-power electric propulsion system selected from mature products to reduce technical risk, assembled into (3) a modern, high-performance demonstration platform to provide useful and compelling data, both for the targeted early adopters and the eventual commercial market.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-21625 , AIAA SciTech 2016; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Flight Tests of a Remaining Flying Time Prediction System for Small Electric Aircraft in the Presence of Faults (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper addresses the problem of building trust in the online prediction of a battery powered aircraft's remaining flying time. A series of flight tests is described that make use of a small electric powered unmanned aerial vehicle (eUAV) to verify the performance of the remaining flying time prediction algorithm. The estimate of remaining flying time is used to activate an alarm when the predicted remaining time is two minutes. This notifies the pilot to transition to the landing phase of the flight. A second alarm is activated when the battery charge falls below a specified limit threshold. This threshold is the point at which the battery energy reserve would no longer safely support two repeated aborted landing attempts. During the test series, the motor system is operated with the same predefined timed airspeed profile for each test. To test the robustness of the prediction, half of the tests were performed with, and half were performed without, a simulated powertrain fault. The pilot remotely engages a resistor bank at a specified time during the test flight to simulate a partial powertrain fault. The flying time prediction system is agnostic of the pilot's activation of the fault and must adapt to the vehicle's state. The time at which the limit threshold on battery charge is reached is then used to measure the accuracy of the remaining flying time predictions. Accuracy requirements for the alarms are considered and the results discussed.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-26923 , Annual Conference of the Prognostics and Health Management Society (PHM) 2017; Oct 02, 2017 - Oct 05, 2017; St. Petersburg , FL; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Verification of Prognostic Algorithms to Predict Remaining Flying Time for Electric Unmanned Vehicles (2018)
    In:  CASI
    Details
    Publication Date: 2019-11-23
    Description: This paper addresses the problem of building trust in the online prediction of a eUAVs remaining available flying time powered by lithium-ion polymer batteries. A series of ground tests are described that make use of an electric unmanned aerial vehicle (eUAV) to verify the performance of remaining flying time predictions. The algorithm verification procedure described is implemented on a fully functional vehicle that is restrained to a platform for repeated run-to-functional-failure (charge depletion) experiments. The vehicle under test is commanded to follow a predefined propeller RPM profile in order to create battery demand profiles similar to those expected during flight. The eUAV is repeatedly operated until the charge stored in powertrain batteries falls below a specified limit threshold. The time at which the limit threshold on battery charge is crossed is then used to measure the accuracy of the remaining flying time prediction. In our earlier work battery aging was not included. In this work we take into account aging of the batteries where the parameters were updated to make predictions. Accuracy requirements are considered for an alarm that warns operators when remaining flying time is estimated to fall below the specified limit threshold.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-29272 , NF1676L-27683 , International Journal of Prognostics and Health Management (ISSN 2153-2648); 9; 021
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Note on the Effects of First-Order Aerodynamic Loads on Propeller Shaft Loads with Emphasis on Counterrotating Propellers (1954)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: An investigation of the 1XP excitation of inclined single-rotation propellers has indicated a new concept for determining propeller shaft forces and moments of an inclined propeller. This report presents preliminary results, in particular to the counterrotating propeller.
    Keywords: Aircraft Design, Testing and Performance
    Type: NACA-RM-A54C30
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Aerodynamically-Actuated Radical Shape-Change Concept (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Aerodynamically-actuated radical shape change (AARSC) is a novel concept that enables flight vehicles to conduct a mission profile containing radically different flight regimes while possibly mitigating the typical penalties incurred by radical geometric change. Weight penalties are mitigated by utilizing a primary flight control to generate aerodynamic loads that then drive a shape-change actuation. The flight mission profile used to analyze the AARSC concept is that of a transport aircraft that cruises at a lower altitude than typical transports. Based upon a preliminary analysis, substantial fuel savings are realized for mission ranges below 2000 NM by comparison to a state-of-the-art baseline, with an increasing impact as mission range is reduced. The predicted savings are so significant at short-haul ranges that the shape-change concept rivals the fuel-burn performance of turboprop aircraft while completing missions in less time than typical jet aircraft. Lower-altitude cruise has also been sought after in recent years for environmental benefits, however, the performance penalty to conventional aircraft was prohibitive. AARSC may enable the opportunity to realize the environmental benefits of lower-altitude emissions coupled with mission fuel savings. The findings of this study also reveal that the AARSC concept appears to be controllable, turbulence susceptibility is likely not an issue, and the shape change concept appears to be mechanically and aerodynamically feasible.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-25725 , AIAA Aviation Technology, Integration, and Operations Conference (AVIATION 2017); Jun 05, 2017 - Jun 09, 2017; Denver, CO; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
    Electronic Resource
    Electronic Resource
    Zur thermischen Zersetzung von Dolomit. V. Kristallitgrößen der Zersetzungsprodukte (1952)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 269 (1952), S. 120-134 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kristallitgrößen der bei thermischer Zersetzung von Dolomit entstehenden Reaktionsprodukte wurden mit Hilfe eines Geiger-Zählrohr-Spektrometers aus der Verbreiterung von Röntgeninterferenzen bestimmt.Bei Zersetzung zu MgO und CaO nimmt die Größe der Kristallite von etwa 60 bzw. 130 Å an mit steigender Temperatur stetig zu. Oberhalb etwa 900° C erfolgt ein starker Anstieg der Kristallitgröße. Die Primärteilchen werden dann größer als etwa 1000 Å, womit die methodisch bedingte obere Grenze der bestimmbaren Kristallitgröße erreicht ist.Bei partieller Zersetzung zu MgO und CaCO3 tritt in der Abhängigkeit der Kristallitgrößen von der Reaktionstemperatur ein Minimum für beide Zersetzungsprodukte auf. Dies erklärt sich durch Überlagerung zweier Einflüsse, der Kristallkeimbildung und des Kristallwachstums. Diese Erscheinung ebenso wie der Befund, daß die CaCO3- bzw. CaO-Kristallite stets beträchtlich größer sind als die MgO-Teilchen, ist in übereinstimmung mit dem aufgefundenen Reaktionsmechanismus der Dolomitzersetzung.Auch bei sinkender Reaktionstemperatur (〈650° C) wird eine gewisse Kristallitgröße nicht unterschritten. Die Zersetzungsreaktionen laufen nämlich mit nennenswerter Geschwindigkeit erst bei Temperaturen ab, bei denen hinreichende Beweglichkeit der Gitterbestandteile vorhanden ist, so daß dann auch bereits Kristallite gebildet werden können.Durch Messung von Integralintensitäten wurde gefunden, daß die Reaktionsprodukte frei von solchen Gitterstörungen sind, welche die Integralintensität beeinflussen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19522690306
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Synthese der d,l-Di-n-alkyl-essigsäuren mit 19 bis 23 C-Atomen. (VI. Mitteil. über isomere und homologe Reihen)Zum 70. Geburtstag von Prof. Karl Thomas, Max-Planck-Institut für Medizinische Chemie, Göttingen. (1953)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 86 (1953), S. 688-692 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Di-n-alkyl-essigsäuren C19H38O2 bis C23H46O2 wurden durch doppelte Malonester-Synthese dargestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19530860605
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  • 8
    Electronic Resource
    Electronic Resource
    Die Schmelzpunkte der isomeren und homologen Reihen der d,l-Oxyparaffine, Ketoparaffine und d,l-Paraffin-carbonsäuren (III. Mitteil. über isomere und homologe Reihen) (1953)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 86 (1953), S. 669-678 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Schmelzpunkts-Reihen der in den folgenden Mitteilungen IV, V und VI beschriebenen reinen isomeren n-d,l-Oxyparaffine, Ketoparaffine und d,l-Paraffincarbonsäuren mit Kettenlängen von 14 bis 23 C-Atomen werden graphisch dargestellt. Alle möglichen Isomeren einer Reihe ordnen sich ausnahmslos in regelmäßigen oder alternierenden Kurven an, die in allen Isomeren-Reihen analog verlaufen, und so Voraussagen über die Schmelzpunkte von noch unbekannten Paraffin-Derivaten erlauben. In einigen homologen Reihen der Oxy-paraffine tritt ein bisher unbekannter treppenförmiger Verlauf der Schmelzpunkte auf.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19530860602
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  • 9
    Electronic Resource
    Electronic Resource
    Über bi-homologe Reihen (VII. Mitteil. über isomere und homologe ReihenVI. Mitteil.: F. Breusch u. E. Ulusoy, Chem. Ber. 86, 688 [1953].*) (1954)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 87 (1954), S. 1051-1056 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Neun bi-homologe Reihen, teilweise bis zu einer Alkylkettenlänge von zweimal 20 Kohlenstoff-Atomen, wurden synthetisiert. Der Verlauf der Schmelzpunktskurven dieser bihomologen Reihen wird besprochen.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19540870719
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  • 10
    Electronic Resource
    Electronic Resource
    Die bi-homologe Reihe der symm. 3-Oxy-3.3-dialkyl-propionsäuren (VIII. Mitteil. über isomere und homologe ReihenVII. Mitteil.: F. Breusch, Chem. Ber. 87, 1051 [1954], voranstehend.*) (1954)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 87 (1954), S. 1056-1058 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die bi-homologe Reihe der 3-Oxy-3.3-dialkyl-propionsäuren bis zur 3-Oxy-3.3-di-eikosyl-propionsäure wurde durch Reformatzky-Kondensation von Bromessigester mit symmetrischen Dialkylketonen dargestellt. Von allen Säuren wurden die N,N'-Bis-[p-dimethyl-amino-phenyl]-ureide hergestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19540870720
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    Paper (German National Licenses)
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