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Aviation History
1914
1914 - 0947.PDF
SEPTEMBER II, 1914. (/UGHT) Then— •KG)*??-'-"[£)'?]»-' a.- 1.B Si A3-*B Si' ' ' 5! (ASl + 2^) ^SS + 2i55? ^5i + The derivative of this function is— ZB 1 A 1 2/? Si 4* /tfil + 2/.'5! ^0 - 2 Si 4 5i = ^-4 5i •ii \ 2 4 _ 4 16 ,, (?-»(M») ' (*•» 952 4 It) 3^ + ^51 "?*+** ** +f* 2 4 The curve shown in Fig 5 then shows the variation in the value of a, a. 4rL K[<*-tr-4ry»i] Fig. 6. N0 plotted as a function of S. This curve shows that in the par ticular case where o, would be zeio, and for a surface 4&_ 4**_ •s - 9 * ^t-0*A-(e ,,1. one has, at the angle of attack a,,, the highest speed of ascent. This 4rA speed becomes tero in the general casc,when S= i-r,g _ ,js .raa tV and when 5 = 00. In the same way it will be found that the maximum speed of ascent N,„ corresponding to the angle a,„ passes through a maximum 4r\ and becomes zero, when 6'= 00 and when 5 = , -nj IT /ft ~_ Ara_ »i •in the general case ; and for this value N,„ = Ai - o ; o„ = a,„ '—~- <See Fi8- 6>" It would suffice to study the variations of Nm as a function of a,, am, ai; one sees, besides, that the derivative of Nm approaches zero by negative values, and approaches infinity by positive values when 5 approaches infinity, and when 5 approaches zero ; also, that when .S = 00, a,, = a,„ — a, ; Nm m JVtt = iVj = 0. The speed of ascent A',, which corresponds to the angle of normal speed al( becomes zero when 5 = 00 and when A *" A'o,[(9 - t) - 2rax] ' This value is greater than that of S for which Nm and A'",, are zero Thus it defines the lowest limit of the surface, whilst the highest limit is determined by the value of S for which N„ becomes a maximum. We have supposed the propeller thrust to be constant. In reality, for great decreases in speed, i.e., for variations of the surface from its lowest limit to infinity, the thrust increases, and, consequently, the slope of ascent i ; but the error in this value does not alter the general form of the results, and remains inappreciable for the attainable values of S, or included within its permissible limits. It can also be proved that the general form of the curve of inclina-s tion is independent of the approximation admitted for the laws of the resistance of the air. The results which we have just attained are, therefore, true in every case. (To be continued.) ® ® ® ® FROM THE BRITISH FLYING GROUNDS. Royal Aero Club Eastchurch Flying Grounds. Naval Flying.—There was very little flying last week owing to the windy weather. The following machines were out:—i, 2, 63 Short's, Flight-Lieut. McClean's Short, all being used for instructional pur poses for young officers. Civilian Flying.—Mr. Alec Ogilvie made a couple of fine flights on his Wright 35 h.p. Brighton-Shoreham Aerodrome. Pashley Bros, and Hale School.—Instructors for last week : C. L. Pashley. Up with instructor :—Mrs. Joseph, Mrs. Vincent, W. Cole. Circuits and eights :— J. Woodhouse, C. Winchester, C. Butler, Mrs. Vincent. C. Butler passed the certificate tests with the usual good style. London Aerodrome, Collindale Avenue, Hendon. Grahame «• White School.—Monday last week, straights with instructor :—Messrs. Carabajal, Duncan, and Morgan, Lieuts. Giles, Haines, and Riggall. Solo straights :—Mr. Mumby. Solo circuits :—Mr. Crowe. Wednesday, straights with instructor :—Messrs. Cara bajal, Duncan, Easter, and Lieuts. Allen, Riggall, Strong, Giles, Haines, Solo straights:—Mr. Strickland, Lieut. Strong. Solo circuits:—Mr. Crowe, Lieuts. Vere and Whitehead. Thursday, straights with instructor :—Messrs. Morgan, Polehampton, Carabajal, Duncan, Morgan, and Stalker, Lieuts. Perry, Riggall, Allen, Giles, Haines, Rosher, and Strong. Straights alone :—Messrs. Mumby and Strick land, Lieut. Strong. Circuits and eights :—Mr. Crowe, Lieuts. Vere and Whitehead. Friday, straights with instructor:—Mr. Carabajal. Instructors for the week :—Messrs. Manton, Merriam, Russell, Shepherd, and Winter. Beatty School.—Monday, last week, Messrs. Cheung 32, Roche Kelly 15, Virgilio 15, Lord 15, and Parker 15. Tuesday, Messrs. Smith 15, and Lord 15. Wednesday, Messrs. W. E. de B. Whittaker 15, Virgilio 15, Hornby 15, Gardner 15, Whitehead 5, and Lieut. Rimington 15. Thursday, Messrs. Parker 15, and Whitehead 5. End of week no flying owing to bad weather. Mr. Andrew Cheung took his Certificate at beginning of week in very good style. Hall School.—During the course of last week In structor Clappen has been out several times flying on Caudron No. 2, and E. Brynildsen out for practice made several good straights, greatly improving in getting direction with tail well up. In the workshops the mechanics are busily over hauling the brevet biplane, re-covering the wings and re-wiring throughout. The 'bus is expected to be completed in a week's time In the meantime practice will continue on the other available machines, and No. 2 Caudron has been fitted with a more powerful motor and is taking the place of the brevet biplane pro tern. 947
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