FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1935
1935 - 0248.PDF
SUPPLEMENT TO FLIGHT 126/ G THE AIRCRAFT ENGINEER JANUAEY 31, 1935, e ins/coil fs Ibs/sq.in. Ref. line D ins, 3: 2: 1-5: 1 -9 •8 • •7 • •6- •3- •4- •3- •2: 15- •09 •08 •07 •06- •05 •04- •03 •02' •015: •Oi: -wo.000 -120,000 -100.000 90.000 -80,000 70000 -60.000 -50.000 -40.000 L 30,000 Connect inner and r outer pairs mb rtieir • intersection mti refline. [~5 -4 -3 -2-5 -1 -1-5 , . -1 •9 •a •7 •6 :-5 •A -3 :-25 •2 -•15 -1- ' d. ins. •5" •4: 3 : • •2 • •15 • -1 - •05- •04- •03- -7/P 76/0 r4A) m -ia -46 -66 -86 -iOG -tte -1+0 -166 .176 -ISO -20c 1-226 NOTE> D must be < 3d Nomogram for helical steel springs (solid circular wire). w ds The formula is : W = - /s =r, where /s = shearing stress, o L) W lbs. fs Ibs/sq.ins. 5000- 4000- 3.000- 2000r 1.000- 800 i 600-j 400 > SOOH 200 • 100 - 50- 40- 30: 20- 10- -140.000 • 120.000 •100.000 -90.000 -80.000 -70.000 -60.000 -50.000 -40.000 -30.000 Connect inner and outer pairs via their intersection ivith ref: line line d ins. •5 -j 4 - • 5 - -6/0 •m •4A) •3/0 -2/0 •0& -1©. •23 •46. •2 - •15- • * •I " •09- •08- •07- •06- - •05 * • •04- •03- -66. -86 •106 -126. -I4S. -I6&. -176. •I8G. -20S. -22s D.ip^ T's •4 -3 •I 1 • •1 • • ' 0 ..4 -•2 NOTE > D must be i 3d d = wire diam. and D mean diam. of coils. W is the load. Nomogram for helical steel springs (solid circular r/ire). The formula is : e = -—- f3 -=, where /s = shearing stress, d = wire diam., D = mean diam. of coils, and e the deflec tion per coil. V the airspeed. When 0.002378 is used, V will be in ft./sec. If it is desired to use V in m.p.h. the value becomes 0.0051. Following are Mr. Sykes's explanations of his four nomo grams : (1) Nomogram connecting V-y/TF, W and kL : This repre sents the fundamental equation L= kL/3o-SV2and a straight edge laid across the chart connects values of the three variables in accordance with the above formula. The chief use of this nomogram is in the rapid estimation of landing speeds and the effects of higher kL due to the use of flap- gear, etc. (2) Nomogram for wind correction of take-off run : This chart has been prepared to eliminate the calculation involved in the use of the usual graph (given, for example, in N.A.C.A. Report No. 450—" The Calculation of Take-off Run," by Walter S. Diehl). The law of this graph is S /V —V \ ,,S3 5s = (~"^v—~) anc* on *kk f°rmula the nomogram is based. The difference between take-off speed and wind speed (Vs-Vw) must be separately calculated, but this can be done mentally. Any variable may be found when the other three are known—always remembering that the inner pair of lines and the other pair of lines are to be connected. (3) and (4) Nomograms for helical steel springs. These charts are based on the well-known formulae for max. load W «• , d 3 . irfsD' — fs — and max. extension per coil = - 5 1) Gd G is taken as 12 X io6 lb./sq. in., being derived from official tests. The range iolb. to s.ooolb. will be found to cover spring sizes usually employed in aircraft engineering. RECORDING TURBULENT FLOW NOTE ON THE USE OF THE INTERFEROMETER I-OR RECORDING TURBU LENT FLOW. By L. F. G. Simmons, M.A., A.R.C.S., and C. Salter, M.A. R. & M. No. 1454. (3 pages and 11 diagrams.) February 5, 1932. Price gd. net. Experiments are described in which an interferometer was used to reveal a jet of carbon dioxide gas issuing from a small tube. In the course of the experiments spark photographs of the jet were taken with a monochromatic fringe system, and also with white light fringes widely separated to give a nearly uniformly illuminated field. A few specimen photographs are reproduced and these show the parallel form of the jet at low speeds, and the expansion which takes place at a short distance from the tube when the velocity reaches about 700 centimetres per second. Since fringes can only be produced in the absence of mechanical vibration, it is doubtful whether the method will prove useful in the investigation of problems of fluid motion met with in aerodynamical research. Though the interferometer his been applied to investigations of fluid motion, as far as is known there is no record of its application to problems of turbulent flow. With an electric spark as the source of illumination in place of a mercury vapour lamp, it proved possible to photograph the steady and also the turbulent flow of a jet of gas issuing from a pipe. The best results were obtained with the fringes adjusted for monochromatic fight, although the definition of the lines was necessarily impaired somewhat by the absence of a monochromatic source. Photographs were also taken with a white-light fringe system, which showed improved definition, but suffered from a loss of general uniformity throughout the field, owing to imperfec tions of the mirrors that were available at the time the experiments were made. Details of the method used are described and a few specimen photographs are appended at the end of the report.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
