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AIRCRAF T ENGINEERING October, 1932 Research Reports and Memoranda Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued free from errors. The method is here taken vessel, whereas the nozzle tube was attached GERMANY up again and given, together with the results, axially to the bottom of the vessel. It was VERKEHRSWISSENSCHAFTLICHEN IN- in a corrected form. found that the jet thus produced is generally STITUTS FUR LUFTFAHRT AN DER of a characteristic hollow spindle shape. When TECHNISCHEN HOCHSCHULE STUTT the stable form of the spindle is disturbed by JAPAN GART breaking open the closed water film the spindle AERONAUTICAL RESEARCH was seen to expand in size suddenly and then (R. Oldenbourg, Munich and Berlin.) INSTITUTE gradually tend to the previous stable form. It Forschungsergebnisse. Part 5. Die was also noticed that the spindle is sensitive to Hochstrassen des Welteuftwerkehms. By IMPERIAL UNIVERSITY, TOKYO th e puff of tobacco smoke gently sent upon it. Carl Pirath. (Price 3.20 marks. ) (Koseikai Publishing Office, Tokyo.) A brief note regarding these phenomena was This issue of "Forschungsergebnisse" (Part 4 Report No. 80. July, 1932. Studies on published in Nature, 129 (1932), 614. The of which was summarised in AIRCRAFT ENGIN laborious task of carrying out the detailed the Sounds Emitted by Revolving Airscrews. EERING, Vol. IV, February, 1932, p. 50), investigation regarding the effects of the Part II. Experiments with Model Airscrews. deals with a present-day problem of world air dimensions of the vessels as well as of the rate traffic that has arisen out of th e progress made By Jûichi Obata, Yahei Yosida and Sakae of discharge, temperature of water, etc., was of recent years in transcontinental and trans Morita, Rigakusi. taken up b y Mr. K. Itô, who was attendin g the oceanic air travel. With the successful opera The nature of the sounds emitted by a re Laboratory as one of the Research Students tion of airship services carried out t o schedule volving airscrew was studied with the aid of of this Institute during the short interval of between Europe and South America, and th e models of one-third and one-quarte r the original time from April, 1931 t o the end of February, constant regular flights over the transcontinen size. Models of six different airscrews were 1932, when he was compelled to leave in order tal and transoceanic airways, the time seemed tested, rotated by means of a noiseless electric t o enter the military service. The report of ripe for an investigation of th e bases for profit motor. The sounds were recorded by a n electric th e results of experiments carried out during able working—from the operational and traffic arrangement consisting of a condenser-micro this short time is given here. The results thus standpoints—with conclusions as t o th e returns phone, amplifier, and an oscillograph, and the far obtained may be of some interest, especially tha t may be expected from the operation of tone-colours of the sounds of different air in connection with the problems of a liquid air services over the world's highways for air screws were studied by analyzing the records. atomizer, though the data obtained are still traffic. The scale effect, the effect of variation of the rather scanty and further studies are desirable geometrical pitch, and th e directional property on many points. of the sounds were also studied. POLAND A notable difference was found in th e nature TRAVAUX DE L'INSTITUT AERO- FRANCE of the sounds emitted by the Reed metal DYNAMIQU E DE VARSOVIE PUBLICATIONS SCIENTIFIQUES ET airscrew made of twisted thin duralumin plate, (Wydane Nakladem Akademji nauk Technic- TECHNIQUES DU MINISTERE DE L'AIR and the airscrew of the usual thick form. znych, Warsaw.) SERVICES DES RECHERCHES DE L' In the former, the fundamental tone, having a No. 6, 1932. frequency corresponding to the product of the AERONAUTIQUE (1) Sur la représentation conforme et number of blades and th e number of rotations (La Rougerie and Gauthier-Villars, Paris.) per second, is prominent only in the plane of biunivoque de l'extérieur d'un cercle sur No . 11, 1932. Etude de la Combustion des rotation, while in the other positions the l'extérieur d'un arc symétrique de conique. Mélanges Gazeux. By R. Duchêne. acoustic spectrum is rather continuous, even By J. Bonder. M. Duchêne has specialised in the study of a t the highest revolutions. On the other (2) U n écoulement du fluide visqueux par flame propagation in combustible mixtures hand, in the airscrew of the usual thick form, le tuyau conique. By P. Szymanski. and, having found from the photographic th e fundamental tone comes out strong at (3) A Note on the Discontinuous Potential. records obtained that with detonating fuels high revolutions, both in the plane of rotation By M. J. Thompson. certain irregularities occur in the curve of the as well as in a position 45 deg. to it. The problem investigated in the first paper propagation of the front of the flame, set him The directional property thus differs with is a special case of the transformation by self to discover whether the intensity of the different airscrews, while in the matter of conformal representation of the outer outline irregularity provided a means of classifying scale effect the smaller size seems to be some of a segment of a straight line (or of a circle) fuels on the basis of their non-liability to what advantageous. into the outer outline of a profile having no detonation, and whether the nature of the Finally, the general effect of the airscrew thickness, made up of one or more analytical irregularity could be made to throw light on sound on our sensation is studied. At slow arcs. It is claimed that the solution given th e cause of detonation. The tests on which rotations, the component having a high but constitutes an advance in the theory of con- M. Duchêne has been engaged since 1927 ar e indefinite frequency predominates, while the formal representation. The theor y is developed discussed in detail in this publication in which low frequency component, especially the funda and a practical method for the numerical the plant evolved for th e purposes of the tests mental tone, becomes louder and louder on calculation is given in detail. by the photographic method is also described. increasing the number of rotations. At the He found that the method allows of a classifica In the second paper the author develops a highest rotation both components attain the tion of fuels in excellent agreement with that theory yielding an exact solution of Stokes' same degree of loudness. established by means of the test motor of th e equations for the case of steady motion of an Ethy l Corporation, and was able to confirm incompressible viscous fluid in a conical tube No . 81. July, 1932. On Hollow Spindle- the results reached by Withrow and Boyd, who of circular cross-section. The curves derived Shaped Liquid Jet. By Kyozi Itô. situate the explosion wave in the last portions are in good agreement with those determined of the fired mixture. He concludes, therefore, experimentally. While engaged in experiments regarding tha t for the prevention of detonation means The third paper deals with the theory some properties of water jets in conjunction must be found to render the normal com developed by S. Neumark for a generalised with Mr. Sin Tanaka, Professor T. Terada hit bustion rapid and as nearly total as possible form of th e discontinuous potential in a previous upon the idea of imparting a revolving motion so as to decrease the explosive energy. issue of these publications (see AIRCRAFT to the wate r before it enters the tubula r nozzle. ENGINEERING, Vol. 4, August , 1932). Although Such a motion was produced by attaching a The report also includes a concise statement the conclusions as far as the y affected the work pair of the inlet tubes tangentially and dia- of the position reached by other investigators, tha t followed were correct, the analysis was no t metrally opposite at the top of a cylindrical and a bibliography of the subject.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Oct 1, 1932
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