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The optical system of the NACA 400,000-frame-per-second motion-picture camera

Description: Report presenting the optical principle of the NACA ultrahigh-speed camera. Simplified sketches are included illustrating the optical principle and main design features of the camera, but without minor design details. A detailed description of the camera is provided as well as some sample photographs taken with the camera.
Date: August 1947
Creator: Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

Relation between spark-ignition engine knock, detonation waves, and autoignition as shown by high-speed photography

Description: "A critical review of literature bearing on the autoignition and detonation-wave theories of spark-ignition engine knock and on the nature of gas vibrations associated with combustion and knock results in the conclusion that neither the autoignition theory nor the detonation-wave theory is an adequate explanation of spark-ignition engine knock. A knock theory is proposed, combining the autoignition and detonation-wave theories, which introduces the idea that the detonation wave develops in autoignited or after-burning gases, and ascribes comparatively low-pitched heavy knocks to autoignition but high-pitched pinging knocks to detonation waves with the possibility of combinations of the two types of knocks" (p. 317).
Date: December 5, 1945
Creator: Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

A study by high-speed photography of combustion and knock in a spark-ignition engine

Description: "The study of combustion in a spark-ignition engine given in Technical Report no. 704 has been continued. The investigation was made with the NACA high-speed motion-picture camera and the NACA optical engine indicator. The camera operates at the rate of 40,000 photographs a second and makes possible the study of phenomena occurring in time intervals as short as 0.000025 second. Photographs are presented of combustion without knock and with both light and heavy knocks, the end zone of combustion being within the field of view" (p. 15).
Date: December 9, 1941
Creator: Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

The NACA high-speed motion-picture camera optical compensation at 40,000 photographs per second

Description: The principle of operation of the NACA high-speed camera is completely explained. This camera, operating at the rate of 40,000 photographs per second, took the photographs presented in numerous NACA reports concerning combustion, preignition, and knock in the spark-ignition engine. Many design details are presented and discussed, details of an entirely conventional nature are omitted. The inherent aberrations of the camera are discussed and partly evaluated. The focal-plane-shutter effect of the camera is explained. Photographs of the camera are presented. Some high-speed motion pictures of familiar objects -- photoflash bulb, firecrackers, camera shutter -- are reproduced as an illustration of the quality of the photographs taken by the camera.
Date: November 6, 1945
Creator: Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

The interdependence of various types of autoignition and knock

Description: A study of the relations existing among pin-point autoignition, homogeneous autoignition, and knock has been made by means of the NACA high-speed camera and the full-view combustion apparatus. High-speed photographic records of combustion, together with corresponding pressure-time traces, of benzene, 2,2,3-trimethylbutane, S-4, and M-4 fuels at various engine conditions have shown the engine conditions under which each of these phenomena occur and the relation of these phenomena to one another.
Date: February 10, 1947
Creator: Olsen, H. Lowell & Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Description: Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only in a part of the cylinder charge which has been previously ignited either by autoignition or by the passage of the flame fronts but which has not burned to completion. Mottled regions in the high-speed Schlieren photographs are demonstrated to represent combustion regions.
Date: November 14, 1942
Creator: Miller, Cearcy D. & Olsen, H. Lowell
Partner: UNT Libraries Government Documents Department

Preknock vibrations in a spark-ignition engine cylinder as revealed by high-speed photography

Description: "The high-speed photographic investigation of the mechanics of spark-ignition engine knock recorded in three previous reports has been extended with use of the NACA high-speed camera and combustion apparatus with a piezoelectric pressure pickup in the combustion chamber. The motion pictures of knocking combustion were taken at the rate of 40,000 frames per second. Existence of the preknock vibrations in the engine cylinder suggested in Technical Report no.727 has been definitely proved and the vibrations have been analyzed both in the high-speed motion pictures and the pressure traces" (p. 223).
Date: September 11, 1944
Creator: Miller, Cearcy D. & Logan, Walter O., Jr.
Partner: UNT Libraries Government Documents Department

End-zone water injection as a means of suppressing knock in a spark-ignition engine

Description: Report discusses the results of an investigation into the effectiveness of water injection into the combustion end zone of a spark-ignition engine cylinder for the suppression of knock. The injection angle was found to be very important for obtaining maximum results. The results of various angles and amounts of water were examined.
Date: September 1944
Creator: Brun, Rinaldo J.; Olsen, H. Lowell & Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

A high-speed motion-picture study of normal combustion, knock and preignition in a spark-ignition engines

Description: Combustion in a spark-ignition engine was investigated by means of the NACA high-speed motion-picture cameras. This camera is operated at a speed of 40,000 photographs a second and therefore makes possible the study of changes that take place in the intervals as short as 0.000025 second. When the motion pictures are projected at the normal speed of 16 frames a second, any rate of movement shown is slowed down 2500 times. Photographs are presented of normal combustion, of combustion from preignitions, and of knock both with and without preignition. The photographs of combustion show that knock may be preceded by a period of exothermic reaction in the end zone that persists for a time interval of as much as 0.0006 second. The knock takes place in 0.00005 second or less.
Date: July 24, 1940
Creator: Rothrock, A. M.; Spencer, R. C. & Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

Analysis of spark-ignition engine knock as seen in photographs taken at 200,000 frames per second

Description: Report discussing a motion picture of the development of knock in a spark-ignition engine, which consists of 20 photographs taken at intervals of 5 microseconds, or at a rate of 200,000 photographs per second, with an equivalent wide-open exposure time of 6.4 microseconds for each photograph.
Date: 1946~
Creator: Miller, Cearcy D.; Olsen, H. Lowell; Logan, Walter O., Jr. & Osterstrom, Gordon E.
Partner: UNT Libraries Government Documents Department