PDF/ocr_dataset_1.jsonl

{"citation_id": "19930090699", "source_url": "https://ntrs.nasa.gov/api/citations/19930090699/downloads/19930090699.pdf", "page_number": 1, "total_pages": 14, "image_filename": "19930090699_p1.jpg", "text": "TECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 369\n\nTESTS ON AN AIRFOIL WITH TWO SLOTS SUITABLE\nFOR AN AIRCRAFT OF HIGH PERFORMANCE\nLift, Drag, Rolling and Yawing Moment Measurements\nBy F. Handley Page\n\nFrom \"Flight,\" January 28, 1926\n\nWashington\nJuly, 1926", "timestamp": "2026-07-19T10:40:06.456440+00:00"}
{"citation_id": "19930090642", "source_url": "https://ntrs.nasa.gov/api/citations/19930090642/downloads/19930090642.pdf", "page_number": 1, "total_pages": 11, "image_filename": "19930090642_p1.jpg", "text": "FILE COPY\nNO 4\n\nAIRCRAFT CIRCULARS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo 80\n\nSTINSON COMMERCIAL AIRPLANE – TYPE S M-1\nA Semicantilever Monoplane\n\nWashington\nOctober, 1927\n\nFILE COPY\nTo be returned to\nthe files of the National\nAdvisory Committee\nfor Aeronautics.", "timestamp": "2026-07-19T10:40:08.916108+00:00"}
{"citation_id": "19930090686", "source_url": "https://ntrs.nasa.gov/api/citations/19930090686/downloads/19930090686.pdf", "page_number": 1, "total_pages": 17, "image_filename": "19930090686_p1.jpg", "text": "# NACA TM 389\n\nFILE COPY\nNO. 1\n\nCASE FILE\nCOPY\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 389\n\nDEVICES FOR PREVENTION OF STALLED FLIGHT\nBy Paul Mazer\n\nFrom \"L'Aéronautique,\" October, 1926\n\nTHIS DOCUMENT ON LOAN FROM THE FILES OF\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\nLANGLEY MEMORIAL AERONAUTICAL LABORATORY\nLANGLEY FIELD, HAMPTON, VIRGINIA\n\nRETURN TO THE ABOVE ADDRESS.\n\nREQUESTS FOR PUBLICATIONS SHOULD BE ADDRESSED\nAS FOLLOWS:\n\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n1724 F STREET, N.W.,\nWASHINGTON 5, D.C.\n\nWashington\nNovember, 1926\n\n[annotation: 17]", "timestamp": "2026-07-19T10:40:12.946530+00:00"}
{"citation_id": "19930090688", "source_url": "https://ntrs.nasa.gov/api/citations/19930090688/downloads/19930090688.pdf", "page_number": 1, "total_pages": 9, "image_filename": "19930090688_p1.jpg", "text": "2+\nCASE FILE\nCOPY\nLoan\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 364\n\nKINETOGRAPHIC FLOW PICTURES\nBy L. Prandtl and O. Tietjens\n\nFrom \"Die Naturwissenschaften,\" Vol. 13\n\nWashington\nMay, 1926\n\nNACA FILE COPY\nLoan expires on last\ndate stamped on back cover.\nPLEASE RETURN TO\nDIVISION OF RESEARCH INFORMATION\nNATIONAL ADVISORY COMMITTEE\nFOR AERONAUTICS.", "timestamp": "2026-07-19T10:40:17.379598+00:00"}
{"citation_id": "19930090732", "source_url": "https://ntrs.nasa.gov/api/citations/19930090732/downloads/19930090732.pdf", "page_number": 1, "total_pages": 12, "image_filename": "19930090732_p1.jpg", "text": "No. 2\nFILE COPY\nNO. 2\nN 62 57351\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nCASE FILE\nCOPY\n\nNo. 351\n\nKIRSTEN-BOEING PROPELLER\nBy H. Sachse\n\nFrom \"Zeitschrift für Flugtechnik und Motorluftschiffahrt,\"\nJanuary 14, 1926\n\nTHIS DOCUMENT ON LOAN FROM THE FILES OF\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\nLANGLEY MEMORIAL AERONAUTICAL LABORATORY\nLANGLEY FIELD, HAMPTON, VIRGINIA\n\nRETURN TO THE ABOVE ADDRESS.\n\nREQUESTS FOR PUBLICATIONS SHOULD BE ADDRESSED\nAS FOLLOWS:\n\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n1724 I STREET, N.W.,\nWASHINGTON 25, D.C.\n\nWashington\nFebruary, 1926", "timestamp": "2026-07-19T10:40:17.763100+00:00"}
{"citation_id": "19930090613", "source_url": "https://ntrs.nasa.gov/api/citations/19930090613/downloads/19930090613.pdf", "page_number": 1, "total_pages": 14, "image_filename": "19930090613_p1.jpg", "text": "file as NACA-TN-44\n\nTECHNICAL NOTES.\n\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nNo. 44.\n\nON THE RESISTANCE OF SPHERES AND ELLIPSOIDS IN\nWIND TUNNELS.\n\nBy\nD. P. Riabouchinsky.\n\nTranslated from\nBulletin of the Aerodynamical Institute of Koutchino,\nBy\nParis Office, N.A.C.A.\n\nPRICES SUBJECT TO CHANGE\n\nJanuary, 1921.\n\n14", "timestamp": "2026-07-19T10:40:24.246651+00:00"}
{"citation_id": "19930090744", "source_url": "https://ntrs.nasa.gov/api/citations/19930090744/downloads/19930090744.pdf", "page_number": 1, "total_pages": 25, "image_filename": "19930090744_p1.jpg", "text": "[annotation: FILE COPY NO 1-W]\n\nCASE FILE\nCOPY\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 361\n\nMETAL AIRPLANE CONSTRUCTION\n\nPaper read at the Third International Congress of\nAerial Navigation held at Brussels in October, 1925.\n\nFILE COPY\nTo be returned to\nthe files of the National\nAdvisory Committee\nfor Aeronautics\nWashington, D. C.\n\nWashington,\nMay, 1926", "timestamp": "2026-07-19T10:40:24.428671+00:00"}
{"citation_id": "19930090703", "source_url": "https://ntrs.nasa.gov/api/citations/19930090703/downloads/19930090703.pdf", "page_number": 1, "total_pages": 13, "image_filename": "19930090703_p1.jpg", "text": "FILE COPY\nNO. 3\n\nTECHNICAL MEMORANDUM\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nProperty of the\nPacific Aeronautical Library\nNo. 394\n\nINDEXED BY P. A. L.\n4\n2\n12\nCopy\n68\n\nTESTING A WINDMILL AIRPLANE (\"AUTOGIRO\")\nBy R. Seiferth\n\nFrom \"Zeitschrift für Flugtechnik und Motorluftschiffahrt\"\nNovember 27, 1926\n\nTM 394\n\nTHIS DOCUMENT ON LOAN FROM THE FILES OF\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\nLANGLEY MEMORIAL AERONAUTICAL LABORATORY\nLANGLEY FIELD, HAMPTON, VIRGINIA\n\nRETURN TO THE ABOVE ADDRESS.\n\nREQUESTS FOR PUBLICATIONS SHOULD BE ADDRESSED\nAS FOLLOWS:\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n1724 F STREET, N.W.,\nWASHINGTON 25, D.C.\n\nWashington\nJanuary, 1927", "timestamp": "2026-07-19T10:40:25.867379+00:00"}
{"citation_id": "19930090742", "source_url": "https://ntrs.nasa.gov/api/citations/19930090742/downloads/19930090742.pdf", "page_number": 1, "total_pages": 27, "image_filename": "19930090742_p1.jpg", "text": "N 62 57388\n\nFILE COPY\nNO. 1 /\n\nNACA-TM-388\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 388\n\nCASE FILE\nCOPY\n\nEXPERIMENTS WITH A SPHERE FROM WHICH\nTHE BOUNDARY LAYER IS REMOVED BY SUCTION\n\nBy Oskar Schrenk\n\nFrom \"Zeitschrift für Flugtechnik und Motorluftschiffahrt,\"\nSeptember 14, 1926\n\nTHIS DOCUMENT ON LOAN FROM THE FILES OF\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\nLANGLEY MEMORIAL AERONAUTICAL LABORATORY\nLANGLEY FIELD, VIRGINIA\nRETURN TO THE\nLANGLEY DISTRIBUTION SECTION\nNATIONAL AERONAUTICS AND\nSPACE ADMINISTRATION\nLangley Field, Virginia\n\nWashington\nNovember, 1926\n\n[annotation: 26]", "timestamp": "2026-07-19T10:40:28.299548+00:00"}
{"citation_id": "19930090699", "source_url": "https://ntrs.nasa.gov/api/citations/19930090699/downloads/19930090699.pdf", "page_number": 2, "total_pages": 14, "image_filename": "19930090699_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 369.\n\nTESTS ON AN AIRFOIL WITH TWO SLOTS SUITABLE\nFOR AN AIRCRAFT OF HIGH PERFORMANCE.*\n\n(Lift, Drag, Rolling and Yawing Moment Measurements.)\n\nBy F. Handley Page.\n\nThe results that are described in this article form a complete series of tests on an airfoil fitted with front and rear slots, the rear slot being formed between the portion of the wing aft of the rear spar and the forward portion of the flap. The section on which these tests were carried out is one that is suitable for an airplane of high performance, and is, in the slot closed position, a slight variation of RAF 15, the camber being increased to accommodate rather larger wing spars than are possible with RAF 15 section.\n\nThe main characteristics of the unslotted wing are similar to those of RAF 15, namely, a maximum lift coefficient of approximately 0.5 with a fairly low minimum drag, and a reasonable movement of the C.P. Slotted, the lift coefficient is increased to 0.8, and with the rear slot open and the flap inclined at $20^\\circ$ angle of attack, the lift coefficient is increased to 1.\n\nHere, then, are comprised the very desirable characteristics of RAF 15 when the slot is closed, together with a lift\n\n* From \"Flight,\" January 28, 1926.", "timestamp": "2026-07-19T10:40:43.070812+00:00"}
{"citation_id": "19930090642", "source_url": "https://ntrs.nasa.gov/api/citations/19930090642/downloads/19930090642.pdf", "page_number": 2, "total_pages": 11, "image_filename": "19930090642_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nAIRCRAFT CIRCULAR NO. 60.\n\nSTINSON COMMERCIAL AIRPLANE - TYPE S M-1*\n\nA Semicantilever Monoplane.\n\nThis is a semicantilever airplane with a closed cabin capable of seating a pilot and five passengers. It employs a high wing with the wing section N.A.C.A. M-6.\n\nF u s e l a g e\n\nThe fuselage is of a conventional design and is constructed of aircraft steel welded together. One-piece steel tie rods are employed at the lower lift strut roots to take the tension across the fuselage. At the wing spar roots at the top, heavy chrome-molybdenum steel tubes are employed to take the compression of the spars.\n\nWooden strips are clamped to the various longerons and verticals to facilitate trimming and interior decorating. The doors are of wooden construction, as are also the window sills. All steel work is wire brushed, then covered with a coat of metal primer and finally covered with one coat of lacquer before assembling.\n\nC a b i n\n\nThe cabin is equipped with six wicker chairs with a six-inch aisle-way between, giving three tiers of two chairs each.\n\n*Prepared by the Stinson Aircraft Corporation.", "timestamp": "2026-07-19T10:40:43.506900+00:00"}
{"citation_id": "19930090724", "source_url": "https://ntrs.nasa.gov/api/citations/19930090724/downloads/19930090724.pdf", "page_number": 1, "total_pages": 17, "image_filename": "19930090724_p1.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 342.\n\nWIRE SUSPENSIONS IN WIND TUNNEL EXPERIMENTS.*\n\nBy Jean Kerneis.\n\nFor a long time there was accorded, in France, but little credit to the results of wind tunnel experiments. This distrust, though exaggerated, was not entirely unfounded. No accord was possible between the different laboratories, since the polars varied, if not with the time, at least with the balance used. We cannot, however, disavow the services rendered by these early experiments, notwithstanding their inaccuracy. From the comparative viewpoint, even inaccurate experiments may give valuable results, render it possible to clear up a problem and indicate the way to follow, but their comparison requires a perfect knowledge of the experimental conditions and is practically impossible between different laboratories. It is, moreover, very hazardous to make assumptions on the constancy or the mode of variation of an error, when its value and even its causes are not known. The present status of experimental aerodynamics requires, moreover, a closer approximation, while the establishment of a project demands absolute accuracy for a good provision of the performances. Our laboratories are trying to attain this accuracy. Certainly the coefficient of similitude $Vl/\\mu$ is far from being reached\n\n* From \"L'Aérophile,\" September 1-15, 1935, pp. 267-273.", "timestamp": "2026-07-19T10:40:43.693394+00:00"}
{"citation_id": "19930090732", "source_url": "https://ntrs.nasa.gov/api/citations/19930090732/downloads/19930090732.pdf", "page_number": 2, "total_pages": 12, "image_filename": "19930090732_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 351.\n\nKIRSTEN-BOEING PROPELLER.*\n\nBy H. Sachse.\n\nA means of propulsion for both aerial and marine craft, differing completely from the conventional screw propeller, has been invented by the German-American, Professor F. K. Kirsten of the University of Washington, with the aid and cooperation of the American airplane manufacturer, Mr. W. E. Boeing. The successful experiments led to the organizing of the \"Kirsten-Boeing Engineering Company,\" in Seattle, Washington, for the further improvement and manufacture of the \"Kirsten-Boeing\" propellers.\n\nThe advantages of this new propeller consist essentially in the adjustability of the thrust in any desired direction, in the plane perpendicular to the axis of rotation of the system, and in its high efficiency. The propeller, which, in appearance, greatly resembles the paddle-wheels used on river steamers, differs fundamentally from the latter, however, in that all the blades work simultaneously in the fluid medium (air or water). This fact necessitates a suitable rotation of the individual blades, in order to control the direction of the thrust. Fig. 1 is a diagrammatic representation of the\n\n* From \"Zeitschrift für Flugtechnik und Motorluftschiffahrt,\" January 14, 1926, pp. 1-4.", "timestamp": "2026-07-19T10:40:48.853451+00:00"}
{"citation_id": "19930090613", "source_url": "https://ntrs.nasa.gov/api/citations/19930090613/downloads/19930090613.pdf", "page_number": 2, "total_pages": 14, "image_filename": "19930090613_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL NOTE NO. 44.\n\nON THE RESISTANCE OF SPHERES AND ELLIPSOIDS IN\nWIND TUNNELS.\n\nBy\n\nD. P. Riabouchinsky.\n\nTranslated from\nBulletin of the Aerodynamical Institute of Koutchino,*\nby\nParis Office, N.A.C.A.\n\nIn the preceding numbers of this Bulletin several\nPapers were devoted to the study of the influence exercis-\ned on the results of measurements by the dimensions and\ntype of the tunnels used in aerodynamical laboratories,\nand on the comparison of these results with observations\nmade in motionless and unlimited air.\n\nWith this object in view I first experimented with\nthin plates. The thrust exerted on these by a relative\nstream is fairly strictly proportional to the square of\nthe speed and may therefore be approximately considered\nas not explicitly depending on viscosity. Consequently,\nif we call P the thrust of the stream on the plates, v\nthe relative speed, S the surface of the plate and\nthe surface of the section of the artificial stream, we\n\n* No. V, p.73.", "timestamp": "2026-07-19T10:40:50.247848+00:00"}
{"citation_id": "19930090705", "source_url": "https://ntrs.nasa.gov/api/citations/19930090705/downloads/19930090705.pdf", "page_number": 1, "total_pages": 19, "image_filename": "19930090705_p1.jpg", "text": "# NACA TM 393\n\nCASE FILE\nCOPY\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 393\n\nSTALL-PROOF AIRPLANES\nBy G. Lachmann\n\nFrom Yearbook of the \"Wissenschaftlichen Gesellschaft für\nLuftfahrt,\" 1925 (\"Berichte und Abhandlungen der\nW.G.L.\" May, 1926)\n\nWashington\nJanuary, 1927\n\n20", "timestamp": "2026-07-19T10:41:01.502454+00:00"}
{"citation_id": "19930090737", "source_url": "https://ntrs.nasa.gov/api/citations/19930090737/downloads/19930090737.pdf", "page_number": 1, "total_pages": 30, "image_filename": "19930090737_p1.jpg", "text": "N 62 57356\n[annotation: C. H. CHATFIELD]\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 356\n\nTHE FUNDAMENTAL PRINCIPLES OF HIGH-SPEED\nSEMI-DIESEL ENGINES\nBy Dr. Büchner\n\nPART I\nA GENERAL DISCUSSION OF THE SUBJECT OF FUEL INJECTION\nIN DIESEL ENGINES AND DETAILED DESCRIPTIONS\nOF MANY TYPES OF INJECTION NOZZLES\n\nFrom \"Jahrbuch der Brennkrafttechnischen Gesellschaft,\"\nVol. V, 1924\n\nWashington\nApril, 1926", "timestamp": "2026-07-19T10:41:11.152695+00:00"}
{"citation_id": "19930090695", "source_url": "https://ntrs.nasa.gov/api/citations/19930090695/downloads/19930090695.pdf", "page_number": 1, "total_pages": 45, "image_filename": "19930090695_p1.jpg", "text": "367\n12779\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNACA TM\n367\n\nNo. 367\n\n[Stamp: BEGINS AND ENDS, Inc. RECEIVED APR 4 1945 PROJECT OFFICE]\n\nAPPLICATION OF THE \"MAGNUS EFFECT\" TO THE\nWIND PROPULSION OF SHIPS\n\nBy L. Prandtl\n\nFrom \"Die Naturwissenschaft,\" Vol. XIII\nJune 2, 1925\n\nWashington\nJune, 1926\n\n45", "timestamp": "2026-07-19T10:41:11.764348+00:00"}
{"citation_id": "19930090724", "source_url": "https://ntrs.nasa.gov/api/citations/19930090724/downloads/19930090724.pdf", "page_number": 2, "total_pages": 17, "image_filename": "19930090724_p2.jpg", "text": "N.A.C.A. Technical Memorandum No. 342\n\nand it seems hardly probable that it ever will be. The size and speed of airplanes are increased much more rapidly than the diameters of wind tunnels or the power of their motors. The effect of this, however, is not so great as has been assumed and its bad repute is due in part to the imputation to it of errors really resulting from totally different causes. These sources of important errors have been gradually eliminated and we may now consider as exact the experimental results obtained in our laboratories.\n\nThe elimination of the rigid supports for the models and their replacement by wires constitute a great improvement by rendering negligible the interactions of the support, phenomena of a very complex aerodynamic order which introduce errors often large and always impossible to evaluate. The use of a balance with wires has, however, certain disadvantages. The aerodynamic resistance of the wires is always very large and their use is rather difficult because the whole suspension lacks rigidity and easily becomes distorted. We will here investigate the nature of these distortions, evaluate the errors they entail and describe the methods for taking account of or avoiding them.\n\nNature of the Distortions\n\nWe will briefly explain the principle of the wire balance (Fig. 1). The model is inverted and suspended by two systems of vertical wires $a_1$ and $a_2$ to the lift balances $B_1$ and $B_2$.", "timestamp": "2026-07-19T10:41:12.417301+00:00"}
{"citation_id": "19930090740", "source_url": "https://ntrs.nasa.gov/api/citations/19930090740/downloads/19930090740.pdf", "page_number": 1, "total_pages": 33, "image_filename": "19930090740_p1.jpg", "text": "[annotation: FILE COPY NO. 3]\n[annotation: FILE COPY NO. 2-W]\n[annotation: FILE COPY NO. 3-W]\n[annotation: FILE COPY NO. 1-W]\n\nCASE FILE\nCOPY\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nNo. 358\n\nTHE FUNDAMENTAL PRINCIPLES OF HIGH-SPEED\nSEMI-DIESEL ENGINES\nBy Dr. Büchner\n\nPART III\nA Discussion of Fuel Mixing and Ignition,\nwith Special Reference to Engines with\nPrecombustion Chambers\n\nFrom \"Jahrbuch der Brennkrafttechnischen Gesellschaft\"\nVol. V, 1924\n\nWashington\nApril, 1926\n\n[annotation: FILE COPY\nTo be returned to\nthe files of the National\nAdvisory Committee\nfor Aeronautics\nWashington, D. C.]", "timestamp": "2026-07-19T10:41:17.823161+00:00"}
{"citation_id": "19930090703", "source_url": "https://ntrs.nasa.gov/api/citations/19930090703/downloads/19930090703.pdf", "page_number": 2, "total_pages": 13, "image_filename": "19930090703_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 394.\n\nTESTING A WINDMILL AIRPLANE (\"AUTOGIRO\").*\n\nBy R. Seifert.\n\nIn No. IV of this volume (1926) of the \"Zeitschrift für Flugtechnik und Motorluftschiffahrt\" there appeared an article \"Ueber den Autogiro von de la Cierva,\"** with the experimental results obtained in the Spanish laboratory at Cuatro Vientos, which were employed for calculating the flight performances of a \"windmill airplane,\" as we shall call it. These calculated flight performances differed so much, however, from those hitherto obtained, as to give rise to doubts concerning the correctness of the tests with models. In the Spanish report it was stated that the reference surface for the calculation of the coefficients $c_a$ and $c_w$ was the area of all four wings. We suspected that this was an error and that the reference surface was really the area of a single wing. When we calculated the flight performances on this assumption, which was subsequently found to be correct, we obtained much more plausible results, as, for example, about 90 km (56 miles) per hour for the maximum speed.\n\nIn order to clear up the matter, the model of a windmill airplane (Fig. 1) was tested in the Göttingen wind tunnel. It\n\n* \"Untersuchung eines Windradflugzeugs,\" from \"Zeitschrift für Flugtechnik und Motorluftschiffahrt,\" Nov. 27, 1926, pp. 483-485.\n\n** This article was essentially a German translation of an article published by De La Cierva in \"Ingeniería y Construcción\" in March, 1924, under the title \"Ensayos aerodinámicos de un modelo de autogiro.\"", "timestamp": "2026-07-19T10:41:20.125259+00:00"}
{"citation_id": "19930090732", "source_url": "https://ntrs.nasa.gov/api/citations/19930090732/downloads/19930090732.pdf", "page_number": 3, "total_pages": 12, "image_filename": "19930090732_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 351\n\noutline of such a propeller with six blades. The arrow A indicates the direction of rotation of the whole system. The requisite control of the blades, for directing the thrust, is obtained by rotating the individual blades in a direction (arrow B) opposite to the direction of rotation of the system as a whole and, in fact, at half the angular velocity, so that each blade turns only $180^\\circ$ during a complete revolution of the whole system. The forces acting on the individual blades, in a medium assumed to be at rest, are then indicated in the diagram. By means of the flow tangential to the blade, the latter derives a force, which is resolved, in the diagram, into two components. One of these components lies in the direction of the flow, tangential to the circumference of the circle, and represents the drag resistance of the blade, which is overcome by the torque of the driving engine. The other component is again resolved into a \"thrust component\" and a lateral force, so that the lateral forces of the different blades counteract one another. The sum of the thrust components is then the total propeller thrust.\n\nFig. 2 shows the path of an individual blade and shows the direction of the resulting flow and its cross-section. The desired direction of thrust can be obtained by changing the position of the blades, without changing the direction of rotation, by a simple device not affected by the forces generated.\n\nIn accord with the above considerations, a small propeller", "timestamp": "2026-07-19T10:41:25.342951+00:00"}
{"citation_id": "19930090668", "source_url": "https://ntrs.nasa.gov/api/citations/19930090668/downloads/19930090668.pdf", "page_number": 1, "total_pages": 35, "image_filename": "19930090668_p1.jpg", "text": "FILE COPY\nNO. 3\n\nonly Copy\nCASE FILE\nCOPY\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\n330\n\nADDRESSES FOR PUBLICATIONS SHOULD BE ADDRESSED\nAS FOLLOWS:\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n2124 I STREET, N.W.,\nWASHINGTON 25, D.C.\n\nMIXING AND IGNITION IN SUPERCHARGED ENGINES\n\nFrom \"Der Motorwagen,\" December 10, 1925\n\nWashington\nApril, 1926\n\nFILE COPY\nTo be returned to\nthe files of the National\nAdvisory Committee\nfor Aeronautics\nWashington, D. C.", "timestamp": "2026-07-19T10:41:33.461523+00:00"}
{"citation_id": "19930090642", "source_url": "https://ntrs.nasa.gov/api/citations/19930090642/downloads/19930090642.pdf", "page_number": 3, "total_pages": 11, "image_filename": "19930090642_p3.jpg", "text": "N.A.C.A. Aircraft Circular No. 60\n2\n\nA door on either side provides access. The visibility is exceptionally good and a non-shatter glass is used throughout. Dual exhaust heaters are connected to each side of the horseshoe exhaust manifold. One heater empties into the front of the cockpit to take care of the pilot and front passenger, while the other empties into the rear of the cabin, taking care of the passengers in the last four seats. Dual Deperdussin control is fitted to the two front seats. The left-hand control is equipped with individual brake pedals which operate either the right or the left wheel or both. The right-hand control is not equipped with brake pedals.\n\nPower Plant\n\nThe airplane is equipped with Wright Whirlwind engine, which is mounted on a steel tube engine mount which is capable of being attached or detached with four bolts. Oil-soaked plywood washers absorb the vibration between the engine and the mount. The mount is constructed of chrome-molybdenum steel tubing with gusset plates welded on each end to reinforce the weld. Steel rivets are then added as a safety precaution. The mount is then annealed to equalize the internal stress in the metal. A seven-gallon oil tank is bolted to the front of the fire wall with flexible connections between the tank and crank case.", "timestamp": "2026-07-19T10:41:41.593883+00:00"}
{"citation_id": "19930090744", "source_url": "https://ntrs.nasa.gov/api/citations/19930090744/downloads/19930090744.pdf", "page_number": 2, "total_pages": 25, "image_filename": "19930090744_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 361.\n\nMETAL AIRPLANE CONSTRUCTION.*\n\nAt the end of the war the scarcity of dry wood compelled airplane constructors to provide for its replacement by metal. Since then the advantages of metal construction have proved many and important.\n\nWood, in general, does not possess well-defined mechanical properties, since these vary with the density, the degree of humidity and the source of the wood. This is not true of metals, whose mechanical characteristics are more constant and easy to control. Inclement weather can diminish the strength of a piece of wood nearly two-thirds. Independently of this reduction in strength, humidity causes deformation and warping of the wings and tail group, which may impair the stability of the airplane. Even the weight of the water absorbed may be enough to affect the performances of an airplane.\n\nIt has often been noticed that ruptures of wood airplanes are more sudden and complete than those of metal airplanes. Wood splits and splinters. Metal yields and bends, thus sometimes enabling a landing, which a wooden airplane would not have time to make.\n\n* Paper read at the Third International Congress of Aerial Navigation held at Brussels in October, 1925.", "timestamp": "2026-07-19T10:41:46.323639+00:00"}
{"citation_id": "19930090739", "source_url": "https://ntrs.nasa.gov/api/citations/19930090739/downloads/19930090739.pdf", "page_number": 1, "total_pages": 33, "image_filename": "19930090739_p1.jpg", "text": "FILE COPY\nNO. 3\n\nFILE COPY\nNO. I-W\n\nTECHNICAL MEMORANDUMS\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nCASE FILE\nCOPY\n\nNo. 357\n\nTHE FUNDAMENTAL PRINCIPLES OF HIGH-SPEED\nSEMI-DIESEL ENGINES\nBy Dr. Buchner\n\nPART II\nA DISCUSSION OF THE SEMI-DIESEL PRINCIPLE\nAND ITS APPLICATION TO VARIOUS TYPES\nOF SOLID-INJECTION ENGINES\n\nFrom \"Jahrbuch der Brennkrafttechnischen Gesellschaft\"\nVol. V, 1924\n\nWashington\nApril, 1928\n\nFILE COPY\nTo be placed in\nthe files of the National\nAdvisory Committee\nfor Aeronautics\nWashington, D. C.", "timestamp": "2026-07-19T10:41:53.804343+00:00"}
{"citation_id": "19930090613", "source_url": "https://ntrs.nasa.gov/api/citations/19930090613/downloads/19930090613.pdf", "page_number": 3, "total_pages": 14, "image_filename": "19930090613_p3.jpg", "text": "- 3 -\n\ncan formulate, by the theory of dynamic similitude:\n\n$$\n\\frac{P}{v^2 S \\rho} = f \\left( \\frac{S}{\\Sigma} \\right)\n\\tag{1}\n$$\n\nThe form of the function $f$ depends on the type of tunnel and on the character of the artificial stream. In using formula (1) it must obviously not be forgotten that this formula is only exact so long as the ratio $\\frac{P}{v^2 S \\rho}$ does not depend on $v$. The resistance of a viscous fluid to the movement of a thin disk in the laminar regime is expressed, we know* as follows:\n\n$$\n\\frac{P}{\\mu v S^{1/2}} = \\frac{16}{\\sqrt{\\pi}}\n\\tag{2}\n$$\n\nor, if we multiply the two members of this equality by $\\frac{\\mu}{\\rho v S^{1/2}}$\n\n$$\n\\frac{P}{\\rho v^2 S} = \\frac{16}{\\sqrt{\\pi}} \\cdot \\frac{\\mu}{\\rho v S^{1/2}}\n\\tag{3}\n$$\n\nThe resistance of a thin disk in the hydraulic regime is approximately equal to\n\n$$\n\\frac{P}{v^2 \\rho S} = K = 0.58\n\\tag{4}\n$$\n\nIn order to determine the critical velocity in the neighborhood of which will probably be effected the passage from law (4) to law (3), we obtain, by putting the sign of equality between the two values of $\\frac{P}{v^2 \\rho S}$,\n\n$$\nv S^{1/2} = \\frac{16}{\\sqrt{\\pi} \\cdot 0.58} \\left\\{ \\frac{\\mu}{\\rho} \\right\\} = 15.8 \\times \\frac{\\mu}{\\rho}\n$$\n\n---\n\n* H. Lamb. Hydrodynamics. Third Edition. § 326.", "timestamp": "2026-07-19T10:42:01.511794+00:00"}
{"citation_id": "19930090724", "source_url": "https://ntrs.nasa.gov/api/citations/19930090724/downloads/19930090724.pdf", "page_number": 3, "total_pages": 17, "image_filename": "19930090724_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 342\n3\n\nThe drag is transmitted by a system of horizontal wires $c_3$, a\nrestraining wire $b_3$ at $45^\\circ$ and a vertical wire $a_3$ attached\nto the drag balance $B_3$.\n\nThe distortions undergone by this system may destroy the\nverticality of $a_1$ and $a_2$ or the horizontality of $c_3$. The\ndistortions may be due either to poor initial adjustment or\nto the stretching of the wires by the aerodynamic stresses.\n\nA. Lack of Verticality of $a_1$ and $a_2$\n\n1. Poor adjustment of balance.- We will suppose that as a\nresult of the poor adjustment of the balance, $a_1$ and $a_2$ make\nan angle $\\alpha$ with the vertical (Fig. 2), O being at O' and\nO' at O' and $a_1$, $a_2$, $b_1$, $b_2$ respectively occupying the\npositions $a'_1$, $a'_2$, $b'_1$ and $b'_2$.\n\nWe will designate by $p a'_2$, $p b'_2$, etc., the vertical\ncomponents of the tension of the wires $a'_2$, $b'_2$, etc., and\nby $t a'_2$, $t b'_2$, etc., the horizontal components of this same\ntension. If we call $\\bar{w}$ the weight of the model, the following\nare the equations of equilibrium of the system before the wind\n\n$$\n\\begin{cases}\n\\bar{w} + pa'_1 + pa'_2 + pb'_1 + pb'_2 = 0. \\\\\ntc'_3 + ta'_1 + ta'_2 + tb'_1 + tb'_2 = 0.\n\\end{cases}\n\\quad (1)\n$$\n\nThe air current generates the aerodynamic forces P and T\nwhich are offset by variations in the tension of $a'_1$, $a'_2$ and\n$c'_3$. Let us call $p'a'_1$, $p'a'_2$, $t'a'_1$, $t'a'_2$ and $t'c'_3$ the", "timestamp": "2026-07-19T10:42:15.540651+00:00"}
{"citation_id": "19930090668", "source_url": "https://ntrs.nasa.gov/api/citations/19930090668/downloads/19930090668.pdf", "page_number": 2, "total_pages": 35, "image_filename": "19930090668_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 360.\n\nMIXING AND IGNITION IN SUPERCHARGED ENGINES.*\n\nMixing\n\nFor carburetor engines which work with a preliminary compression of the charging mixture, there are two principal methods of mixing: 1, with a suction carburetor; 2, with a pressure carburetor.\n\nThe employment of a suction carburetor on a supercharged engine (Fig. 1) necessitates no change in the normal fuel-delivery and atomization mechanism. The supercharger draws the finished mixture from an ordinary carburetor and forces it, previously compressed, into the working cylinder. The longer intake pipe hereby necessitated and its considerable enlargement by the intervening supercharger impair the homogeneity of the mixture and tend to cause precipitation of the fuel, especially at low revolution speeds, due to the smaller gas velocity and the lack of compression heat (since the preliminary compression is low).\n\nIn single-stage turbo-compressors, the homogeneity of the mixture is undoubtedly increased at higher revolution speeds. It has, indeed, been proposed to effect a further diminution in the size of the larger fuel drops after leaving the carburetor\n\n* From \"Der Motorwagen,\" December 10, 1925, pp. 773-782.", "timestamp": "2026-07-19T10:42:18.183659+00:00"}
{"citation_id": "19930090739", "source_url": "https://ntrs.nasa.gov/api/citations/19930090739/downloads/19930090739.pdf", "page_number": 2, "total_pages": 33, "image_filename": "19930090739_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 557.\n\nTHE FUNDAMENTAL PRINCIPLES OF HIGH-SPEED SEMI-DIESEL ENGINES.*\n\nBy Dr. Büchner.\n\nPART II.\n\nA Discussion of the Semi-Diesel Principle and Its Application to Various Types of Solid-Injection Engines.\n\nMcKechnie's indicator diagrams of 1910 differ but little from the constant-pressure diagrams of Diesel engines with air injection. This is comprehensible, since, at that time, the constant-pressure line was still considered an essential characteristic of the Diesel engine and McKechnie did not contemplate changing the principles and limits of the Diesel process, his idea being only to replace the air-injection method by simple mechanical injection (\"solid injection\"), while retaining the high compression pressure unchanged.\n\nDuring the last decade, the question of the most favorable combustion line has often been the subject of both theoretical and practical investigations. Thereby freer and deeper conceptions of the form of the combustion line have been evolved and thus it has come about that the indicator diagrams\n\n*From \"Jahrbuch der Brennkrafttechnischen Gesellschaft,\" Vol. V (1934), pp. 75-90.", "timestamp": "2026-07-19T10:42:20.530585+00:00"}
{"citation_id": "19930090703", "source_url": "https://ntrs.nasa.gov/api/citations/19930090703/downloads/19930090703.pdf", "page_number": 3, "total_pages": 13, "image_filename": "19930090703_p3.jpg", "text": "N.A.C.A: Technical Memorandum No. 394\n\nwas similar to the Spanish model described in No. IV, but had a diameter of only 60 cm (23.62 inches). The four wings of polished basswood were flexibly fastened to the spherical hub by means of plate springs, so that the latter could assume the direction of the resultant of the lift and centrifugal force. Each wing was 24 cm (9.45 in.) long and 4.4 cm (1.73 in.) wide. Once the symmetrical profile 429 (corresponding to the Spanish test) was used, and the other time the cambered profile 387.\n\nIn order to be able to hold the windmill in the tunnel, its axis was fastened to a T-shaped support extending in the direction of the air stream. With the aid of a circular guide, divided into degrees, the angle of attack of the windmill plane could be varied between $\\alpha = 0$ and $90^\\circ$. The angle of attack of the profile chord with reference to the windmill plane is designated by $\\beta$.\n\nThe polar and torque curves were plotted for several different angles of attack $\\beta$. In order to obtain throughout the whole course of a polar curve the most constant possible index value (product of the chord and relative air speed), the rotational speed was kept as constant as possible, by suitably adjusting the wind velocity.\n\nThe resistance of the T-support and spherical hub was subtracted from the measured values, so that the resistance values given in the accompanying tables represent only the drag of the revolving wings.", "timestamp": "2026-07-19T10:42:20.878425+00:00"}
{"citation_id": "19930090688", "source_url": "https://ntrs.nasa.gov/api/citations/19930090688/downloads/19930090688.pdf", "page_number": 2, "total_pages": 9, "image_filename": "19930090688_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 364.\n\nKINETOGRAPHIC FLOW PICTURES.*\n\nBy L. Prandtl and O. Tietjens.\n\nAccording to a method worked out by Professor F. Ahlborn in Hamburg, the flow of water can be photographed by strewing on its surface fine particles (such as lycopodium spores, grass seed, or powdered aluminum) and making short time-exposures. Each particle travels a certain distance during the exposure and is photographed as a short straight line. The total of all these short lines accordingly produces a picture which shows the direction of flow at every point and also its velocity (by the length of the line). With the right amount of powder and a suitable length of exposure, the latter run together so as to indicate the streamlines directly.\n\nIf it is desired to make such pictures with a kinetograph, in order to determine the temporal succession of the flow phenomena, the difficulty may easily arise that the marks will be too short on the individual negatives, due to the shortness of exposure, so that the streamlines will not be recognizable. We therefore changed the driving mechanism of a kinetograph, so that the illumination lasted only 7/8 of the time allotted for each exposure, 1/8 being allowed for the shifting of the film\n\n* \"Kinematographische Strömungsbilder,\" reprinted from \"Die Naturwissenschaften,\" Vol. 13, pp. 1050-1053.", "timestamp": "2026-07-19T10:42:23.306954+00:00"}
{"citation_id": "19930090642", "source_url": "https://ntrs.nasa.gov/api/citations/19930090642/downloads/19930090642.pdf", "page_number": 4, "total_pages": 11, "image_filename": "19930090642_p4.jpg", "text": "N.A.C.A. Aircraft Circular No. 60\n3\n\nG a s o l i n e S u p p l y\n\nThe gasoline is carried in two wing tanks located in the\nfirst bay of the wings and gravity feed is maintained between\nthese tanks and the two auxiliary tanks of $1\\frac{1}{2}$ gallons each.\nThese two auxiliary tanks are located to the rear of the fire\nwall and have an air vent which opens to the atmosphere above\nthe wing. The purpose of these two small tanks is to main-\ntain a head of gasoline for the carburetor at all times. Thus\nwhen the supply is nearly exhausted in the large flat wing\ntanks and the drainage is necessarily slow during maneuvers a\nconstant quantity of gasoline is maintained during any sharp\nbank, zoom or dive.\n\nA two-way switch located in the line shuts off or turns\non either wing tank. Gravity feed is maintained from the two\nsmall tanks of the cabin to the carburetor. Flexible connec-\ntions are supplied at necessary points to diminish vibration.\n\nC o n t r o l s\n\nTwo out of the four controls are accomplished by push pull\ntubes. The stabilizer and elevator controls are actuated by\nbell cranks, torque tubes and push pull tubes. These tubes run\nthrough graphite bearings which not only keep the tubes from\nbuckling but lubricate them as well. These bearings require\nno attention over a period of two years. With this type of con-", "timestamp": "2026-07-19T10:42:27.670499+00:00"}
{"citation_id": "19930090740", "source_url": "https://ntrs.nasa.gov/api/citations/19930090740/downloads/19930090740.pdf", "page_number": 2, "total_pages": 33, "image_filename": "19930090740_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 358.\n\nTHE FUNDAMENTAL PRINCIPLES OF HIGH-SPEED\nSEMI-DIESEL ENGINES.*\n\nBy Dr. Büchner.\n\nPART III.\n\nA Discussion of Fuel Mixing and Ignition,\nwith Special Reference to Engines with\nPrecombustion Chambers.\n\nIn connection with Hesselman's experiments, it was incidentally shown how quantitative observations of the air currents methodically made, may not only contribute to ultimate success, but may also form the indispensable basis for it. The Deutz horizontal solid-injection engine is a further proof of this contention.\n\nIt is one of the few solid-injection Diesel engines which antedate the war (Fig. 26). It works with a relatively low compression (25-30 atm.). When the fuel is gas oil, spontaneous ignition occurs at 25 atmospheres. Gas oil is therefore generally used as the priming oil, when a difficultly ignitible fuel, such as alcohol or coal-tar oil, is used for continuous operation. The engine is but slightly sensitive to the nature of the oil used.\n\n* From \"Jahrbuch der Brennkrafttechnischen Gesellschaft,\" Volume V (1924), pp. 90-106.", "timestamp": "2026-07-19T10:42:34.356691+00:00"}
{"citation_id": "19930090741", "source_url": "https://ntrs.nasa.gov/api/citations/19930090741/downloads/19930090741.pdf", "page_number": 1, "total_pages": 40, "image_filename": "19930090741_p1.jpg", "text": "FILE COPY\nNO. 2\nFILE COPY\nNO. 1-W\n\nCASE FILE\nCOPY\n\nNATIONAL ADVISORY COMMITTEE\nFOR AERONAUTICS\n\nTECHNICAL MEMORANDUMS\n\nNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS\n\nAPR 22\nMAILED\n\nNo. 359\n\nFLIGHT TESTS ON AIRPLANES\n\nBy Heinrich Koppe\n\nFrom \"Berichte und Abhandlungen der Wissenschaftlichen\nGesellschaft fur Luftfahrt,\" July, 1925\n\nFILE COPY\nTo be returned to\nthe files of the National\nAdvisory Committee\nfor Aeronautics\nWashington, D. C.\n\nWashington\nApril, 1926", "timestamp": "2026-07-19T10:42:42.266060+00:00"}
{"citation_id": "19930090642", "source_url": "https://ntrs.nasa.gov/api/citations/19930090642/downloads/19930090642.pdf", "page_number": 5, "total_pages": 11, "image_filename": "19930090642_p5.jpg", "text": "N.A.C.A. Aircraft Circular No. 60\n4\n\ntrol the surfaces are operated through a fixed mechanical system,\nand offer little or no backlash. Although they are slightly\nheavier than the cable controls they are believed much better.\n\nThe rudder control and aileron control are as yet operated\nby cables. The stabilizer is actuated by a left-hand lever\nwhich is connected through to the front spar of the stabilizer,\nthus the setting of the stabilizer can be accomplished by a\nsingle movement.\n\nThe elevator and ailerons are operated by two 14-inch ply-\nwood wheels which slide straight in and straight out from the\ninstrument board and turn to the right or left.\n\nW i n g s\n\nThe spars and ribs are made of spruce while the drag tubes\nare made of steel tubes. The spars are of the routed type.\nThe front one, carrying most of the load, is left full at the\nstrut point and is routed on a taper inside and outside of this\npoint. The rear spar is left full the entire distance and is\nnot routed. The ribs are built up of spruce and plywood.\nDouble drag tubes and wires reinforce the wing against torsion.\n\nThe aileron is constructed entirely of steel tube welded\ntogether and fabric covered and is actuated by a push pull tube\nrunning along the rear of the rear spar. Instead of the con-\nventional bell crank arrangement at the aileron, an Arens con-\ntrol is used. This consists of a coil spring with cable inside", "timestamp": "2026-07-19T10:43:07.482677+00:00"}
{"citation_id": "19930090732", "source_url": "https://ntrs.nasa.gov/api/citations/19930090732/downloads/19930090732.pdf", "page_number": 4, "total_pages": 12, "image_filename": "19930090732_p4.jpg", "text": "N.A.C.A. Technical Memorandum No. 351\n\nof 10.23 inches diameter and 5.91 inches length of blade was tested in the wind tunnel of the University of Washington. The functioning of this experimental propeller proved very satisfactory. A larger model enabled the performance of more accurate experiments on the revolution speeds and the forces generated at various relative speeds, between the propeller and the flowing medium, and established the fact that the best result depends on the ratio of the width of the blades to the diameter of the propeller. The results thus obtained rendered it possible to undertake experiments on a larger scale.\n\nThe ability to change the direction of thrust is very advantageous for an airship with its three-dimensional directions of motion. If the propellers are installed with their axes of rotation perpendicular to the vertical plane of the airship, it is then possible to direct the thrust upward, in order to make the airship descend, or to direct the thrust downward, so as to make the airship rise, or to drive the airship either forward or backward. If, on the other hand, the propellers are so disposed that their axes of rotation lie in the vertical plane, then the thrust can be exerted in any direction in the horizontal plane for steering the airship laterally. The maneuverability of the airship is thus extraordinarily increased.\n\nA large airship propeller was then made, as seen on the testing stand in Fig. 3. It had 24 blades 4 ft. 9.1 in. long and 22 in. wide, the diameter of the whole propeller being", "timestamp": "2026-07-19T10:43:14.670634+00:00"}
{"citation_id": "19930090699", "source_url": "https://ntrs.nasa.gov/api/citations/19930090699/downloads/19930090699.pdf", "page_number": 4, "total_pages": 14, "image_filename": "19930090699_p4.jpg", "text": "N.A.C.A. Technical Memorandum No. 369\n3\n\nTable I (Cont.)\n\nConstruction of Auxiliary Airfoil.\n(Ordinates given as fractions of the chord.)\n\n| Distance from Leading Edge | Height to Under Surface | Height to Top Surface |\n| :--- | :--- | :--- |\n| 0 | 0.0143 | 0.0143 |\n| 0.01 | 0.0278 | 0.0297 |\n| 0.02 | 0.0360 | 0.0385 |\n| 0.03 | 0.04275 | 0.0451 |\n| 0.04 | 0.04780 | 0.0495 |\n| 0.05 | 0.0520 | 0.0539 |\n| 0.06 | 0.0560 | 0.0572 |\n| 0.0702 | 0.05975 | 0.05975 |\n\nHorizontal thickness at 0 dist. from L.E. = 0.001735.\nChord of auxiliary airfoil as fraction of the chord = 0.0834. Gap of front slot as fraction of chord = 0.025.\nForward extension of auxiliary airfoil for front slot open as fraction of chord = 0.0668.\nLeading edge of auxiliary airfoil on chord line.\nThe opening of the forward slot is effected by moving forward the auxiliary airfoil on links pivoted within the leading edge. With slot closed the airfoil is of standard RAF 15 section. With slot open the chord of the airfoil is increased by the amount which the airfoil moves forward.", "timestamp": "2026-07-19T10:43:20.258669+00:00"}
{"citation_id": "19930090741", "source_url": "https://ntrs.nasa.gov/api/citations/19930090741/downloads/19930090741.pdf", "page_number": 2, "total_pages": 40, "image_filename": "19930090741_p2.jpg", "text": "NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS.\n\nTECHNICAL MEMORANDUM NO. 352.\n\nFLIGHT TESTS ON AIRPLANES.*\n\nBy Heinrich Koppe.\n\nNo one nowadays undertakes to build an airplane or airship without careful preliminary calculations and practical tests with models. Unfortunately, experiments seldom have been performed on the finished aircraft themselves, for verifying the results of such preliminary work. This is due partly to a fundamental aversion to such experiments and partly to fear of the difficulties and cost, as also to a certain mistrust of the reliability of results obtained on aircraft.\n\nIf I succeed in dissipating some of these apprehensions and prejudices, the object of my lecture will be accomplished. In order, however, not to raise your expectations too high, I should remark in advance that there is nothing fundamentally new about my experiments. I am prompted to make this report to you on the experiments I performed as a coworker with the \"Deutsche Versuchsanstalt für Luftfahrt,\" only by the hope of being able to present methods for making flight tests on airplanes in a new, practical form.\n\n* From \"Berichte und Abhandlungen der Wissenschaftlichen Gesellschaft für Luftfahrt\" (A supplement to \"Zeitschrift für Flugtechnik und Motorluftschiffahrt\"), July, 1925, pp. 38-47.", "timestamp": "2026-07-19T10:43:22.304158+00:00"}
{"citation_id": "19930090740", "source_url": "https://ntrs.nasa.gov/api/citations/19930090740/downloads/19930090740.pdf", "page_number": 3, "total_pages": 33, "image_filename": "19930090740_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 358\n\nThe engine has a divided compression chamber of the kind much used in small gas engines (Fig. 27). The larger compartment is formed by the cylinder proper, in which the piston works; the smaller, by the valve chamber into which open the fuel-injection valve, the air-intake valve and the exhaust valve. A cylindrical neck connects the valve chamber with the slightly conical end of the working cylinder. The working piston has a conical head (called \"displacement head\" or simply \"displacer\"), which, toward the end of the compression stroke, forms a constriction between the two chambers (Fig. 28) and, in common with the neck and the annular chamber, helps to form an annular opening and an adjacent, gradually expanding annular nozzle which, in turn, opens into the full circular cross section formed by the annular chamber.\n\nBy this diffuser, which has a variable cross section, there is generated, during the whole injection process, an enveloping mantle, which is in a state of lively agitation from its origin at the mouth of the annular nozzle, due to the frequent changes in direction and in cross section. This agitation is intensified when the individual air filaments, on issuing from the annular nozzle on their way toward the cylinder axis, mutually push one another from their direction of motion and assume the form of a hollow cone, which is reversed, as regards the cone formed by the annular nozzle, and opens toward the valve chamber and is gradually dispersed in eddies.", "timestamp": "2026-07-19T10:43:23.511296+00:00"}
{"citation_id": "19930090668", "source_url": "https://ntrs.nasa.gov/api/citations/19930090668/downloads/19930090668.pdf", "page_number": 3, "total_pages": 35, "image_filename": "19930090668_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 360\n\nby means of a rapidly rotating centrifugal blower. One English inventor even goes so far in using a single-stage turbo-compressor as to omit the carburetor altogether and to leave the atomization of the fuel injected into the intake pipe of the compressor entirely to the centrifugal blower.\n\nHence the suction carburetor is universally used on all American racing cars with single-stage turbo-compressors. It is also used on the Mercedes (an 8-cylinder 2-liter engine with a Roots supercharger), the Guyot (with a Cozette rotary supercharger), the Delage (a 12-cylinder V engine with two Roots superchargers), Bignan (with a Roots supercharger) and the Sunbeam (a 6-cylinder 2-liter engine with a Roots supercharger). It must be remembered that these are all on racing cars, which are not often run at low revolution speeds.\n\nThe disadvantages of this system seem to be so small, however, that many constructors prefer to put up with them rather than with the greater complexity of the pressure carburetor.\n\nA pressure carburetor must be used when the supercharger is a turbo-compressor with two or more stages. In such a supercharger the larger fuel drops, thrown off by centrifugal force, collect in the by-pass channels which connect the separate pressure stages, so that on the one hand, no homogeneous mixture is formed and, on the other hand, in the event of back-firing through the carburetor, these fuel deposits easily ignite and may cause dangerous explosions.", "timestamp": "2026-07-19T10:43:23.714435+00:00"}
{"citation_id": "19930090642", "source_url": "https://ntrs.nasa.gov/api/citations/19930090642/downloads/19930090642.pdf", "page_number": 6, "total_pages": 11, "image_filename": "19930090642_p6.jpg", "text": "N.A.C.A. Aircraft Circular No. 60\n5\n\nrunning in a bent brass tube. This allows the push pull action\nto be deflected through a 90° angle to the aileron horn. The\ngas tanks are hung between the spars on three padded steel straps\nand have no rigid mechanical connection to the spars.\n\nL a n d i n g G e a r\n\nThe landing gear is of the conventional split type with\nthe shock absorber connecting the two halves under the center\nof the fuselage. Each half rotates about two bolts located on\neither longeron. Chrome-molybdenum steel is used throughout\nand is heat treated to a strength of 180,000 pounds per square\ninch. The tubular struts are streamlined on the rear side\nonly with balsa wood. A heavy safety cable is supplied in case\nthe shock absorber cord fails.\n\nL i f t S t r u t s\n\nThere are four struts which brace the wings to the fuse-\nlage. Each of these struts has a screw adjustment on the lower\nend which facilitates rigging the wings. The struts consist\nof steel tubing, streamlined both fore and aft with balsa wood.\nThe whole is then covered with fabric and doped.\n\nT a i l G r o u p\n\nThe entire tail group is made up of steel welded construc-\ntion. 1½-inch tube constitutes the spars, while smaller tubing", "timestamp": "2026-07-19T10:43:24.807157+00:00"}
{"citation_id": "19930090703", "source_url": "https://ntrs.nasa.gov/api/citations/19930090703/downloads/19930090703.pdf", "page_number": 4, "total_pages": 13, "image_filename": "19930090703_p4.jpg", "text": "N.A.C.A. Technical Memorandum No. 394\n3\n\nThe following consideration was decisive for the calculation\nof the coefficients $c_a$, $c_w$ and $c_m$. Our wing represented a wind-\nmill revolving at low speed. In windmills it is customary to\ndetermine the resistance for the whole circle and, in general, it\nis true that $c_w$ at idling speed is always of the order of mag-\nnitude of 1, either for a swift runner with only a few narrow\nwings or a slow runner with many wide wings. It is a natural as-\nsumption, however, that the wings are set at the most favorable\nangle of attack for utilizing the wind energy (smaller for swift\nrunners and larger for slow runners). In this most favorable\ncase $c_w$ is therefore independent of the area of the wings. It\nmay be assumed that a similar principle applies to the lift, so\nthat it seems justifiable, even for windmill wings, to adopt the\nwhole circle as the reference area. Hence we have\n\n$$c_a = \\frac{A}{\\frac{\\rho}{2} v^2 \\pi R^2}, \\quad c_w = \\frac{W}{\\frac{\\rho}{2} v^2 \\pi R^2}, \\quad c_m = \\frac{M}{\\frac{\\rho}{2} v^2 \\pi R^3}$$\n\nThe reference axis for the longitudinal moment M is the\nlateral axis passing through the center of the windmill. The\nreference length is the radius R.\n\nThe revolution speed was recorded by the small revolution\ncounter shown in Fig. 1, and stated in the form of the ratio\nu/v (u being the peripheral speed at the wing tips and v the\nwind velocity).\n\nAt zero angle of attack no measurement could be made, since", "timestamp": "2026-07-19T10:43:27.641409+00:00"}
{"citation_id": "19930090739", "source_url": "https://ntrs.nasa.gov/api/citations/19930090739/downloads/19930090739.pdf", "page_number": 3, "total_pages": 33, "image_filename": "19930090739_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 357\n\nof the so-called \"solid-injection\" Diesel engines, now gradually coming into publicity, differ greatly from the diagrams of the original Diesel engines and often remind us strongly of the diagrams of explosion engines. They have decidedly sharp points and only a slight development in the direction of the constant-pressure line, though the latter increases somewhat as the load is increased. Unlike the well-known indicator diagrams of explosion engines, the compression pressures are higher and the pressure increase (the ratio of the maximum pressure to the compression pressure) is less than in explosion engines, though it is likewise affected by the engine loading. It seems entirely appropriate to designate such engines, whose cycles lie between those of the older explosion engines and those of the original Diesel engines (constant-pressure engines) and whose indicator diagrams are accordingly referred to as \"mixed diagrams,\" as \"semi-Diesel engines,\" after the precedent of the Americans, English and French. It must be remembered, however, that they constitute an engine type with flexible limits, in which the hot-bulb engines can be included, as is often done by Americans.\n\nFig. 16 shows indicator diagrams of the Deutz Engine Works, Körting Bros. Co., and Ruston & Hornsby. For the Deutz VII and the Körting engines, so-called \"shifted diagrams\" are given alongside the regular indicator diagrams. In the Deutz VII, the maximum pressure is 38-40 kg/cm² (540-569 lb./sq. in.) at a...", "timestamp": "2026-07-19T10:43:30.877433+00:00"}
{"citation_id": "19930090732", "source_url": "https://ntrs.nasa.gov/api/citations/19930090732/downloads/19930090732.pdf", "page_number": 5, "total_pages": 12, "image_filename": "19930090732_p5.jpg", "text": "```markdown\nN.A.C.A. Technical Memorandum No. 351\n4\n\nabout 15 ft. 1.1 in. On the left stands the driving engine, a\n400 HP. Wright airplane engine which, through a reduction gear,\ndrove the propeller at only 225 R.P.M. It thus generated a\nthrust of about 212 pounds. Fig. 4 shows the propeller running.\nThe small streamers indicate the direction of flow. The pic-\nture also shows the balance for measuring the thrust, which is\nsuspended between the propeller and a fixed point. The hub is\ncast aluminum. The rim (Fig. 6) is constructed of duralumin,\nwhile steel cables are used for bracing. Some of the supports\nfor the blade axles are also shown. On the driving side, the\ncast piece with the four openings, through which the radial\ndriving shafts for rotating the blades are introduced, are\nshown in Fig. 7. Fig. 8 shows the structure of an individual\nblade with a duralumin tubular axle, duralumin ribs and fabric\ncovering. After good results had been obtained with these ex-\nperimental propellers, as regards efficiency, facility of con-\ntrol and quiet operation, owing to the low revolution speed,\nit was planned to install the Kirsten-Boeing propellers on the\nAmerican airship \"Shenandoah,\" as shown in Figs. 9-10. It is\nseen that the outer rim was left off, so that the blades pro-\nject directly into the open air. There were six main propel-\nlers thus designed, with their axes at an angle of $30^\\circ$ to the\nhorizontal plane. With these propellers it is possible to so\nadjust the thrust as to produce forward and backward and up-\nward and downward motions of the airship. The two rear propel-\n```", "timestamp": "2026-07-19T10:43:33.152210+00:00"}
{"citation_id": "19930090695", "source_url": "https://ntrs.nasa.gov/api/citations/19930090695/downloads/19930090695.pdf", "page_number": 3, "total_pages": 45, "image_filename": "19930090695_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 367\n2\n\nknown by artillerists and ball players. When real \"balls\" were\nstill used, artillerists had early noted certain irregular de-\nviations in their trajectories. B. Robins expressed his opin-\nion in 1742 that those deviations were due to the rotation of\nthe balls. He subsequently demonstrated experimentally the\ntruth of his assumption. Toward 1830, in order to control the\nformerly very irregular rotations, bullets with an eccentric-\nally located center of gravity were used. It was found that\nwhen such a ball was loaded with the center of gravity down,\nthe shot regularly fell short, and that when the center of\ngravity was up the shot was long, since the pressure of the\npowder gases (being directed against the center of the ball)\ncaused a downward rotation in the first case and an upward ro-\ntation in the second case. In like manner, placing the center\nof gravity on the right or left caused a corresponding deflec-\ntion to the right or left. This deflection could not be ex-\nplained by the assumption of a lateral impulse at the mouth\nof the gun, because experiments with disks placed at different\ndistances from the muzzle showed that the trajectory was con-\ntinuously deflected.\n\nIn order to settle the question, the well-known Berlin\nphysicist, G. Magnus, a teacher of Helmholtz, performed several\nlaboratory experiments in 1852 (Cf. the article on Gustav Mag-\nnus by P. Pringsheim, \"Die Naturwissenschaften,\" Vol. XIII,\np. 49, 1925). In one of his experiments, he set a brass cylin-", "timestamp": "2026-07-19T10:43:41.350456+00:00"}
{"citation_id": "19930090724", "source_url": "https://ntrs.nasa.gov/api/citations/19930090724/downloads/19930090724.pdf", "page_number": 4, "total_pages": 17, "image_filename": "19930090724_p4.jpg", "text": "N.A.C.A. Technical Memorandum No. 342\n\nnew projections of these tensions.\n\nThe equilibrium equations then become\n\n$$\n\\begin{cases}\n\\overline{w} + P + p'a'_1 + p'a'_2 + pb'_1 + pb'_2 = 0. \\\\\nT + t'c'_3 + t'a'_1 + t'a'_2 + tb'_1 + tb'_2 = 0.\n\\end{cases}\n\\tag{2}\n$$\n\nFrom equations (1) and (2) we deduce\n\n$$\n\\begin{cases}\nP + (p'a'_1 - pa'_1) - (pa'_2 - pa'_2) = 0. \\\\\nT + (t'c'_3 - tc'_3) + (t'o'_1 - to'_1) + (t'o'_2 - to'_2) = 0.\n\\end{cases}\n$$\n\nIn the first equation $(p'a'_1 - pa'_1)$ and $(p'a'_2 - pa'_2)$ are the stresses measured on the balances $B_1$ and $B_2$. Their sum is therefore equal to the lift.\n\nIn the second equation $(t'c'_3 - tc'_3)$, the stress is measured on the balance $B_3$. This stress is therefore equal to the drag, to within the error $(t'a'_1 - ta'_1) + (t'a'_2 - ta'_2)$.\n\nWe now have\n\n$$\n\\frac{t'c'_1 - ta'_1}{p'a'_1 - pa'_1} = \\tan\\alpha = \\frac{t'a'_2 - ta'_2}{p'a'_2 - pa'_2}\n$$\n\nwhence the error =\n\n$$\n(t'a'_1 - ta'_1) + (t'a'_2 - ta'_2) = \\tan\\alpha \\left[ (p'a'_1 - pa'_1) + (p'a'_2 - pa'_2) \\right] = P \\tan\\alpha.\n$$\n\nOrder of magnitude of the error.— The error in the drag is therefore proportional to the lift, i.e., it varies with the angle of attack. It depends also on the distance between the", "timestamp": "2026-07-19T10:43:46.560936+00:00"}
{"citation_id": "19930090688", "source_url": "https://ntrs.nasa.gov/api/citations/19930090688/downloads/19930090688.pdf", "page_number": 3, "total_pages": 9, "image_filename": "19930090688_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 364\n\nin preparation for the next exposure. In order not to overtax the mechanism, the velocity of the shifting film must not be greater than in ordinary operation, in which about 0.4 of the time can be allowed for the actual exposure and 0.6 for the shifting of the film (at least in our camera, which is an old type made by Liesegang in Düsseldorf). On the basis of 16 exposures per second in ordinary operation, we thus obtained 3 exposures per second, which were sufficient for our purpose.\n\nThe \"film time-pictures\" thus obtained are poorly adapted for kinetoscopic reproduction, since they give a very unnatural effect, even when correspondingly retarded by copying each individual picture several times in succession on the positive film, as is done in trick pictures. The object of such pictures is not the same as in motion pictures, but only to enable the separate observation of each successive picture. Obviously the successive pictures show the path of each particle practically without interruption, since only 1/8 of the distance is lost for each exposure. Hence the accelerations can be determined, from which conclusions can be drawn regarding the field of force underlying the motion.\n\nSince the device we employed might be applicable to other kinds of motion analysis, we will add a few words concerning it. In addition to the normal 8-picture crank, there is also an axle for 4 pictures per revolution. We mounted a Maltese cross on the latter axle, as is customary in kinetoscopes.", "timestamp": "2026-07-19T10:43:49.102308+00:00"}
{"citation_id": "19930090668", "source_url": "https://ntrs.nasa.gov/api/citations/19930090668/downloads/19930090668.pdf", "page_number": 4, "total_pages": 35, "image_filename": "19930090668_p4.jpg", "text": "N.A.C.A. Technical Memorandum No.360\n\nFor this reason there must be provided, between the supercharger and the engine, a sufficiently large safety valve, which is held by springs and opens into the free air when a certain pressure is exceeded. Such a safety valve is advisable, even on engines with pressure carburetors, only here it must be inserted between the supercharger and the carburetor.\n\nA pressure carburetor is, moreover, the simplest device when the supercharger does not run all the time (Mercedes touring car) or when it does run all the time, but is not continuously discharging into the engine (Fiat, Alfa Romeo). When the compressor is not running, or is discharging into the open air, the engine then draws the mixture through the carburetor. With the supercharger in use, however, the carburetor intake opening is closed and the carburetor receives the compressed air from the supercharger. This, however, necessitates some changes in the normal carburetor.\n\nIn a normal carburetor, due to the negative pressure in the intake pipe, the fuel is sprayed from the nozzle, since the float chamber is under atmospheric pressure. There must be a sufficient pressure difference between the float chamber and the intake pipe to enable the spraying process, whereby the quantity of fuel sprayed is approximately proportional to the pressure difference.\n\nIf, however, a positive pressure is produced in the intake pipe, the fuel does not flow out of the nozzle but is", "timestamp": "2026-07-19T10:43:55.878083+00:00"}
{"citation_id": "19930090688", "source_url": "https://ntrs.nasa.gov/api/citations/19930090688/downloads/19930090688.pdf", "page_number": 4, "total_pages": 9, "image_filename": "19930090688_p4.jpg", "text": "N.A.C.A. Technical Memorandum No. 364\n3\n\nIn Fig. 1, a is the axle of the Maltese drive, which is itself driven in turn by an electric motor, by means of a cord, and is provided with a flywheel. The 4-picture axle b carries the Maltese cross and a cogwheel, which engages with another cogwheel on the axle c (diagrammatically represented, since the cogwheel on the 8-picture axle really intervenes). In short, the action of the mechanism is such that (with a uniform rotational speed of the axle a) the Maltese cross rests during 3/4 of a rotation of the axle a, but then, during the remaining 1/4 rotation of the axle a, is itself carried through a quarter revolution by means of the pin s, which at first imparts to it a gradually accelerated motion and then, at the end, a correspondingly retarded motion. The axle c thereby makes a full revolution, only the middle portion of which is utilized for advancing the film, so that for exposing and advancing the film, about 7/8 and 1/8 respectively, of a revolution of the axle a is utilized.\n\nThe pictures we have thus far taken concern the phenomena of flow past rotating and non-rotating cylinders, in which, after our experiments on the Magnus effect, we felt an especial interest. (Cf. \"Naturwissenschaften\" 1925, p. 93 ff.) For these pictures we had a water tank 35 cm wide, 30 cm deep and 3 m long (about 1.15 x 0.98 x 9.84 ft.). The obstacle used was a vertical cylinder, 4.5 cm (1.77 in.) in diameter and 25 cm (9.84 in.) long, which was rotatable on ball bearings", "timestamp": "2026-07-19T10:44:12.010346+00:00"}
{"citation_id": "19930090741", "source_url": "https://ntrs.nasa.gov/api/citations/19930090741/downloads/19930090741.pdf", "page_number": 3, "total_pages": 40, "image_filename": "19930090741_p3.jpg", "text": "N.A.C.A. Technical Memorandum No. 359\n\nReferring to the statements of the preceding speaker,* I will first comment briefly on the experiments performed in Copenhagen on the Rohrbach all-metal boat seaplane Ro II 1 (Fig. 1). I do so, because in these experiments, there was such excellent cooperation of theoreticians and practitioners, of designers and constructors, and of aviators and scientific observers (or \"instrument doctors\" as they are sometimes jestingly called) and, furthermore, because the results obtained in the numerous flights furnished the real reason and ground for further practical and theoretical conclusions.\n\nSince the Rohrbach metal airplanes are built on a rather large scale, even as regards the space arrangement, it is allowable for the scientific observer to be bold and demand the best place for himself and his numerous instruments. This is doubtless the front end of the fuselage with the front window (Fig. 2): From this vantage point, the whole airplane can be readily seen and it is easy to communicate with the pilot. This position is also nearest to the undisturbed air flow. With the help of a wooden frame, a \"flying laboratory\" was installed to fit the available space (Fig. 3). Naturally, everything was measured, observed and plotted, that could be learned from the instruments or by personal observation. Special importance was attached to the determination of flight character-\n\n* Adolf Rohrbach, \"Neue Erfahrungen mit Grossflugzeugen,\" Jahrbuch der W.G.L., 1924, pp. 23-37. See also N.A.C.A. Technical Memorandum No. 353.", "timestamp": "2026-07-19T10:44:21.581034+00:00"}