FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1925
1925 - 0238.PDF
and are built either in steel or in Duralumin. The inner and more highly-stressed struts are of fairly heavy gauge steel. Less severely loaded struts are of thinner gauge steel, while the most lightly loaded struts are of Duralumin. Thus, with the same section a wide range of strut strengths is available. One of our sketches shows how the struts are built up, and is self-explanatory. The struts can be built of smaller width for the same strength as a tubular strut, or, conversely, for the same width and resistance will be stronger. The fairing is of three-ply wood, and is extremely light. It is slid over the projecting edges of the strut, so that after use the fairing can be slipped off and the strut examined if desired. We believe this strut construction is protected by a patent. The Bristol " Jupiter " engines are mounted on tubular structures in the gap between the wings, and each engine is attached to the main engine structure by a swivelling mount- ing patented by Boulton and Paul several years ago. This APRIL 23, 1925 is a diaphragm bolted to the walls of the tube and having leak holes and a spring-loaded valve opening upwards. The tube is filled with oil up to just above the diaphragm, and air is pumped into the space above the oil to the required pres- sure. This, of course, is done with the leg fully extended. A neat air pressure gauge is fitted in the upper end of the tube, and has a needle valve arrangement for placing the gauge out of circuit when the undercarriage is in use. A jack is then placed under the undercarriage and the machine raised until the leg is extended. The pressure employed is, we believe, 60 lbs. per square inch, and when this pressure has been obtained, the needle valve is screwed down on its seating, and the gauge thus cut off from communication with the inside of the tube. A somewhat similar telescopic leg is employed for the tail skid, and actually the machine can land and touch with the skid first without causing any damage, so that there does not THE BOULTON AND PAUL BUGLE " : 1, details of fuselage construction. 2, the construction of the special inter-plane struts, whose main structure is of metal, while the removable fairing is of three-ply wood. 3, a wing spar section, and, 4, a very light tip-up seat in the forward gunner's cockpit. mounting facilitates access to the back of radial engines, and conical or tapered bolts are used so as to take up any wear that might take place. The engines and their supporting structures are enclosed in almost perfect streamline casings, as will be seen from the photographs. The fuel supply is by direct gravity feed, there being two petrol tanks, one for each engine, supported underneath the top plane. The tanks also are visible in the illustrations. The oleo undercarriage fitted on the " Bugle " is of parti- cularly robust construction, and has been designed to give exceptional shock-absorbing qualities. It has not been found possible to give a sectional drawing of one of the " legs," but a sketch shows the external appearance, and, with a few words of explanation, may serve to indicate the general principle. The oleo-pneumatic leg consists, as usual, of two tubes, one of which telescopes inside the other. The lower tube in this case passes inside the upper, and carries at its upper end a piston with small leak holes, and also a spring-loaded valve opening downwards. The lower tube passes, of course, through a stuffing-box in the lower end of the upper tube. .Inside the upper, larger-diameter tube, near its upper end, appear to be much doubt about the shock-absorbing qualities of this form of oleo-pneumatic leg. It is regretted that performance figures may not be pub- lished, otherwise it would, we think, be obvious that in the Bugle " Mr. North has reached a very high performance for a machine designed to carry all sorts of " frightfulness," in addition to a crew of three and fuel for a very large cruising range. This is due, in some measure, to the all-metal con- struction, which enables a not inconsiderable saving in struc- ture weight to be made, but also to careful aerodynamic design in so far as this is possible in a machine which must have all manner of excrescences dictated by military con- siderations. The wing section is the ubiquitous R.A.F. 15, but the aspect ratio is high, about 8, and careful stream- lining has been carried out wherever possible, such as to undercarriage legs, tail skid telescopic leg, and, of course, to the engine housings. Incidentally, it may be of interest to mention that the Boulton and Paul aerodynamics staff has now commenced to calculate wing sections on the Joukowsky- Prandtl theory, and have verified certain sections by wind tunnel tests. The agreement between calculated and experi- mentally-determined, values has been found to be excellent. 238
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
