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Aviation History
1921
1921 - 0130.PDF
FEBRUARY 24, 1921 THE HANDLEY PAGE WING BY P. HANDLEY PAGE THE paper to which everyone interested in aviation has longbeen looking forward was read by Mr. Handley Page on Thursday of last week (February 17), before the RoyalAeronautical Society. There was a very good attendance at the lecture, which was followed by an interesting andinstructive discussion. Giving as it does, for the first time, a full account of the results obtained with the new H.P.wing, we publish Mr. Handley Page's paper in full, and we feel that we need not make any apology for doing so. Thepaper is one of most unusual interest, and it may well be that the Handley Page discovery will have the most far-reachingeffect upon the future of commercial aviation. The following is the full text of the paper. The present Paper is a record of experimental work carriedout with a view to overcoming the phenomenon of " burbling." As is well known, the total pressure on an aerofoil is the sumof the positive pressure on the under side and the negative suction on the upper. If this negative suction can be madeto increase progressively with increasing angle of incidence on the back of the plane, and the pressure increases con-tinuously as some function of the angle. At angles greater than this critical value the air leaves the back of the plane,a ' dead ' air region is formed there, and any reduced pressure or suction on the plane back tending to increase the total' lift ' is then solely due to the drag of the ' live ' air stream at the edges of this ' dead ' air region." A further referencef was made later on in the Paper :—'' The critical angle at which the ' live ' air leaves the plane back is reached earlier in the case of planes of high aspectratio, and the latter accordingly do not have such high maximum values as the planes of lower aspect ratio." With planes of high aspect ratio there is not the same facility for the ' feeding in ' of fresh air at the plane sides toact as a link between the plane and ' live stream,' and there- fore the ' live stream ' leaves the plane back at an earlierstage than in the case of the plane of lower aspect ratio." In _Fig. 1 is the set of curves reproduced from the 1911PapefC showing the pressure on aerofoil as a function of the ANGLE or Incidence • 0 • SO to angles greater than heretofore, the maximum value of theaerofoil lift coefficient will be increased. The effect of such an increase on aeroplane design depends upon the magnitudeof the increase and the extra structure weight of the device necessary to obtain it. The present method which is nowdescribed has been evolved from experimental data, and an outline of the results is given below.In a Paper which I read before the Royal Aeronautical Society in April, 1911—ten years ago—I attempted an analysisof the somewhat meagre results then available on the pressures on plane and curved surfaces moving through the air. Theeffect now known as " burbling " was referred to as follows :— * " To obtain a law giving the normal pressure on a planeas a continuous function of the angle of incidence of the angle of incidence. It will be observed that the squareaerofoil marked P. 1 : 1 continues lifting until 40", whereas the aerofoil of aspect ratio 6.25 : 1 (marked L. 6.25 : 1)" burbles ' between io~ and 150. If, then, it were possible to convert the high aspect ratio aerofoil into a series of squareones and maintain the same conditions as in a square plane, higher maximum lift coefficients should be obtained.Fig. 2 is an aerofoil of aspect ratio 6J converted into six square planes by five slots, each parallel to the chord of theplane. With the^slots open the total "lift" on the plane 1 r/6.2. - H.P. aerofoil with five longitudinal slots mpinging air from o to 90 is impossible owing vo the twodistinct forms of flow thai occur on the back of the plane. From the horizontal position of the plane up to an anglevarying in magnitude from io'J to 50° depending on the aspect ratio, shape and curvature of the plane, the air hugs the backof the plane, the suction due to the rushing air is felt directly * " The Pressures on Plane and Curved Surfaces Moving Through theAir."—"Aeronautical Society of Great Britain Journal." April, IJII. Page 48. 1 h i i— A jt-i 4 1 i -1 -_ £ -E1G 4 i JI 1 Plane section with early type slot was slightly increased, and the " burble " took place at 14° instead of 130 (see Fig. 3).Improved results were later obtained with this form of slot, but this line of investigation was abandoned in favourof a transverse slot (see Fig. 4), which was tested on an aero- foil of R.A.F./15 section (see Fig.. 5). The shape of the t " The Pressures on Plane and Curved Surfaces Moving Tbrougto the Air."—"Aeronautical Society of Great Britain Journal." April, 1911. Pages 55 and 56. X..^, I3O
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