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Aviation History
1933
1933 - 0197.PDF
July 27, 1933 Supplement to FLIGHT Edited by C. M. POULSEN July 27, 1933 CONTENTS Pa"e Zati Flap= and Aileron*. By Temple N. Jovce, Zap Development Corporation, Dundalk, Baltimore, Ma 41 Engine Research 47 Technical Literature— Summaries of Aeronautical Research Committee Reports .. 52 ZAP FLAPS AND AILERONS* By TEMPLE N. JOYCE, Zap Development Corporation, Dundalk, Baltimore, Ma. FOR the last five or six years, the demand on the part of operators for increased high speed has forced designers practically to disregard the importance of the steadily increasing landing speeds of aircraft. During the same period there has been another influence that lias allowed us still further to neglect this factor. It the fact that modern engines are so reliable and forced landings so seldom that their importance was looked upon with more or less contempt. This was trticularly true during the boom days when everybody «as using a new engine and landing speeds were only thought of in terms of getting into recognised airports. , ee things have occurred since then, however, that h »ve again brought to the front the importance of low landing speed: First, a very distinct realisation that th e public was afraid of aviation because of high stalling speeds and the frequent crack-ups with serious consequences; second, the fact that increased high * could not be obtained without increasing still high landing speeds unless some new aero dynamic development was brought into existence; third, d range and wing loadings went up, take-off run •increased and angle of climb decreased alarmingly. Zap development is a successful effort to reduce th ' speeds without impairing high speed and effi'' k''ing about the best overall increase in the iioi " °^ an aeroPlane with the least added complica- eeded •ExPefimental work on the Zap flap was pre- rot ' and stimulated by investigations on a Flettner the \ UOroPlane °y Mr. Edward F. Zaparka, through high-"".1'"118 °f the Chrysler Corporation. Because of aroUlV leacti°ns obtained by the change in flow iiivJ-1 a.°ylinder, the research drifted to a practical __J^?ation of the problem of influencing the flow p«.,(. - . — 1 Presented at A.S.M.E. Chicago Meeting, June 26-30, 1933. around an airfoil. The first work was done in a miniature tunnel and later supplemented by larger-scale work in the New York University tunnel under the able consultation of Professor Klemin. Subsequently, the flap was installed on a commercial Aristocrat cabin aeroplane of 165 h.p. and flight tests proved that the flap was very effective. These tests also showed that though lift increases were essential for slow-speed land ings, almost equally important was the question of lateral control; Zap ailerons were the result, and will be covered in later paragraphs. In the spring of 1932 the Aristocrat with Zap flaps and ailerons was presented to the B/J Aircraft Cor poration through one of its financial connections in New York. I shall outline here chronologically the questions and answers that were made and the reactions that the writer had to the Zap development because, in all proba bility, in so doing, it is believed that most of the ques tions that one would want to know regarding Zap flaps and ailerons will be answered. Our first impressions at the B/J plant when we were told that a plane was to be sent down to us were that it was just another flap aeroplane and that it would really be a waste of time to look it over, particularly because, to our best knowledge, lift coefficie»ts of 0.0044 engin eering units were the maximum that could be expected on a single flap applied to a Clark Y airfoil. When the aeroplane arrived at our field it was observed thai it had a split flap and the ailerons were placed above the wing. This caused considerable apprehension as it was felt that the ailerons in such a position would surely be blanketed when the plans was brought to a stall, and would not only be inadequate but dangerous. The writer was quite reluctant to fly the machine at first, but finally did so with the expectation of finding that the ailerons would be completely ineffective at 10 or 15 miles above the stalling speed of the aeroplane. Much to our surprise, they were found to be very effective down to and below the stall of the aeroplane with flaps up, and materially improved when the flaps were clown. After a very short flight in the air, the plane was brought down with the conviction that it was a horrible example of an aeroplane but that the flaps and Zap ailerons almost made it a reasonable vehicle. Our next step was to investigate the wind tunnel data which had been carried out by New York University. The results shown in the data presented by Mr. Zaparka were extremely interesting, and the B/J 754 a
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