FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1910
1910 - 0079.PDF
JANUARY 29, 1910. Other* again rely on a special formation of the main planes them selves, or by setting the planes at a dihedral angle. The setting of the planes at an angle is open to question, because when a certain tilt in the machine is reached, this initial angle tends to increase rather than diminish the instability. The gyroscope, perhaps, appeals to one as the most feasible and practical device for the purpose. The Marmonier Stabiliser, which is a combination of a pendulum and gyroscope, is the nearest approach to a practical application of this method of obtaining stability, and avoids the disadvantages of either gyroscope or pendulum used separately, as it avoids the brutality of a fixed gyro scope and the continued oscillation of a pendulum. Constructional Materials.—For main constructional purposes wood is undoubtedly the best material, and should be used as much as possible, on account of its lightness and flexibility. The use of steel or aluminium should be avoided, except for small parts and fittings. For large members where great strength is required, ash is most suitable. For short beams and spars spruce should be used, and where a very light wood is required, which is not subject to If LIGHT TABLE 11 Name of Timber. (Specimens 2 ins. square.) English oak American white Honduras mahogany English ash Canadian ash Spruce Yellow pine Bamboo Tran .—Properties of ;verse Strength. Deflection in ins. Span 6 ft. •H j§ 3 0 ; j "5 tfl ins. 2*52 I-92 i'9i6 1 -62 2-7S 1-23 2-I2 — ins. •117 •208 •083 •os •125 •05s 1-833 mat e ction. ! Ulr i Defl e sigh t ss a eakin g in l b P5 ins. 1 7-7i 813 Woods. Breakin g r.sq . in . th. ;. p e ?2 lie Str e igh t i n c > H th pe r ren g lbs w.S rushin g sq. U 75705800 8'83! 8047000:6050 4-06 8o2;30ooj627o 8-63! 862 7-471 638 5-19 670 4-66 627 — — 37006700 55005600 39004700 25004040 6000 — b. f t u ^h t pe r We i S« 2.5 35 52 52 35 42 19 Ratios. 0 gth t c ~ sil e St r Wei g H 130 280 86 71 106 0 igt h hin g S t Wei g Cru s 100 242 179 izg 107 in :I34 59-5 96 3i6 — great strain, American whitewood may be employed. Bamboo naturally appeals to one as an ideal material for aeroplane construc tion, but it has grave disadvantages, in that it is very treacherous and extremely difficult to join up to. Wooden beams and struts can be considerably strengthened by means of binding with fabric and waterproof glue, also very satisfactory hollow spars can be made by this method. The bracing of the machine is usually effected by means of steel piano wire adjusted by tightening screws. Fig. 4 shows a section of a double-covered main plane. The top and bottom strips are generally of spruce, glued and pinned to the front and back edges after having been set to the desired curve by steaming. The trans verse beams are of ash, spliced at> the joints and strengthened by means of fish-platas. The main struts are made of spruce, and should be of ichthyoid section. Outriggers are usually made of spruce, cut to an H section for lightness. Considerable weight may be saved in the selection of a good covering material. Excellent qualities of waterproofed canvas are obtainable, in weight varying from 2$ oz. to 4 03. per square yard, and with a breaking strength as great as 2,000 lbs. per square yard. Aluminium and steel sheets of about Tis in. and TD"OTS m- ln thickness, respectively, have been used for this purpose. Metal has the advantage of being more easily fixed to the framework, and maintains its curvature better than canvas under pressure. In Table II is given a list of woods suitable *or aeroplane con struction. Another British-made Aeroplane Fabric WE have received from Messrs. Frankenburg and Sons a sample of their British-made aeroplane fabric, with which they are already obtaining a considerable amount of success. The fabric is made of Sea-Island Chassis.—The chassis is perhaps the most troublesome part of the machine as far as weight is concerned, and requires careful design to keep the weight within reasonable limits, especially where wheels are employed. One of two methods may be adopted ; either skates, which are generally made of curved wood and may be shod with metal, or mounting the machine on wheels arranged on the castor principle and fitted with shock-absorbers. With the former arrangement it is necessary to use a starting device, which necessitates the start being made at a given place only, but a lower-powered engine may be employed than with the second method of mounting the machine on wheels, though with the latter method there is the advantage of being able to start on any suitable ground. To arrive at the approximate distance in feet required to raise the machine from the ground, the following formula may be used, pro viding the conditions are favourable :— W x VJ x v 2g x b.h.p. x 550 x E W = total weight of machine, V = designed speed of machine in feet per second, v — mean velocity in feet per second from zero to V, E = overall efficiency of machine. The curves in Fig. 8 should be of interest to the aviator, in actua practice, as they show that in starting or landing the machine may be subject to altered conditions owing to variation of the wind velocities. Vtloti'ty ar vary tny huffifs I 1 \ FIG. 8. The authors have endeavoured to draw attention to a few of the most important points, but have not included the subject of engines, as, although the engine is of vital importance to successful flight, vet it can hardly be said to come under the heading of " the design and construction of aeroplanes." The conquest of the air has been partially accomplished ; yet, before it can be said to be completely achieved, it will be necessary to be able to make use of ascending currents and remain poised in mid-air, and accomplish those delicate feats of balance which enable some species of birds to soar in the air without any apparent expenditure of energy. ® ® cotton, and is prepared with a rubber face on both sides, or on one side only, as may be required. With fourteen coats of pure Para rubber on one face only the weight per sq. yd. is 3 ozs. The fabric has a tensile strength of 95 lbs. on a 5 in. strip, and costs is. 5</. per yard run with a width of 36 ins. 75
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
