Search results

364,065. Cooling Cylinders.. Fedden. A. H. R. and Bristol Aeroplane Co., Ltd., Filton House, Bristol. Sept. 30, 1930, No. 29337. [Class 7 (ii).]

IT is the intention of the German Aircraft Industry to reciprocate the visit of their friends of the British Industry to the Berlin Exhibition last year and a number of firms concerned will therefore secure admission to Olympia in serried ranks, for the purpose of showing, for the first time, their products to the British Public. It will be a matter of particular importance to the German Trades concerned, to see to it that their representation at the British Show at the Olympia is worthy of the occasion.

The wing spar described in the parent specification is modified by arranging the corrugated booms with their edge parts directed inwardly and forming them with Hat sides A6, B6 to scat the stiffeners C, D and bracing members I, J, which are arranged outside the booms and formed as channel‐section struts with outwardly directed flanges. The stiffeners C, D have Hanged pad pieces E1 fitted in their ends, extensions E3 being formed on the pad pieces for securing them to blocks G5, H5 fixed to bridge pieces G, H. The stiffeners and bracing members are secured to the booms by hollow rivets F. Rivets passed through distance tubes L strengthen the members C, D, and similar bracing may be placed across those booms that are in compression at points between their connections to the stiffeners C, D. The gauge of the metal may vary to suit the load on the girder; for example, one boom may be thicker than the other and the thickness or the spacing of the members C, D may be varied. The diagonal struts I, J may be fixed to the booms by separate connections instead of overlapping the members C, D.

THE “Do.X 1” was launched on July 12, 1929, hence we can now look back on the experience collected in the operation of this new aircraft over two and a half years. This experience has been gained with three different types: the original type aircraft, or “Do X.1” (Fig. 1), with air‐cooled engines; the same aircraft in its modified form, the “Do.X.1a” (Fig 2), with water‐cooled engines, and the “Do.X.2” (Umberta Maddalena), the first of two flying boats built on behalf of an Italian firm, with water‐cooled Fiat engines. (Fig. 3.)

A variable‐pitch airscrew includes a differential screw mechanism connected with two skew gear‐wheels of opposite sense, mounted coaxially of the airscrew shaft, said skew wheels being adapted to be restrained against rotation for the purpose of altering the pitch of the propeller blades. Within the hollow driving shaft of a propeller are two coaxial shafts 17, 18 having at their inner ends spur wheels 23, 24 which are in mesh with corresponding teeth formed on two brake drums 23a, 24a that are furnished with brake bands 23b, 24b controlled by a lever 26c. The outer ends of the shafts 17, 18 carry skew gear wheels 29, 30 of opposite sense which engage permanently pairs of gear wheels 31, 32, and 33, 34 mounted on parallel transverse shafts 35, 36 and 37, 38. The shafts 35, 37 are connected by means of right and left‐hand skew gears 39, 40 with a transverse rotatable sleeve 41 splined on to a shaft 44. This shaft 44 bears two differential screw threads 45, 46, the smaller of which 46 engages a threaded boss 47, whilst the other engages a screwed lug 48 on a slidable sleeve 55 having an open jaw member 57 which engages an eccentric pin 58 at the root of a blade. When the hand lever 26c is moved to brake one or other of the wheels 23, 24 one or other of the skew gears is given a relative rotation and a corresponding movement takes place of the shaft 44 whereby the blade is altered in pitch. As an alternative to the brake drums the shafts 17, 18 may be furnished with notched discs adapted to be engaged by spring‐influenced pawls carried by a lever similar to the lever 26c.

In an aircraft fuselage or motor gondola wherein all the stresses occurring are taken up by a spatial skeleton structure a, an outer covering is provided formed by individual reinforced panels b, c, d, e, each covered on one side with fabric, sheet‐metal or plywood f, g, h, i. All the panels may be removably secured to the structure a by means of clamps, screws, bolts, or the like, or some only of the panels at places where easy access to the interior of the fuselage is desired, the remainder of the fuselage being provided with a non‐removable covering. Each panel is reinforced by a lattice structure, or by profiled members, or by other means and may be mounted with its covered surface towards the interior of the fuselage. The panels may be interchangeable and some may be covered on both sides.

336,795. Indicating and recording torsional vibration of shafts. Gerard, I. J., and Carter, B. C, Royal Aircraft Establishment, South Farnborough, Hampshire, and Mansell, H. C, Rathgar, Ashley Road, Walton‐on‐Thames. Oct. 17, 1929. No. 31565. [Class 106 (ii).] Dynamometers, rotary transmission: with recording‐apparatus.—Comprises a construction of the type in which the torsional vibrations of a shaft are used to tilt a mirror reflecting a beam of light on to a screen of photographic plate.

Hollow blades b for air‐screws are constructed from a metal block provided with a blind coaxial bore c first by forging, stamping or rolling to produce the requisite elongation of the block and to impart a cross‐section of desired shape. Secondly, by producing a deformation of the block wall by means of pressure exerted from the inside or from the outside, and finally to form the end a of the blade in a manner suitable for attachment to the propeller hub. When an external pressure is used the interior is filled with plastic material or fluid under pressure. Alternatively, a former or core is introduced having the desired inner shape of the blade. In another method the hollow block is placed in a mould having the required external form of the blade. Preferably the root a of the blade which is hollow is provided with a thread whereby it may be screwed on to radial pins on the hub block

A valve, which is opened by the operation of the engine, prevents delivery of fuel from a throttle‐actuated accelerator pump to the induction system, when the engine is not running. During operation of the engine, the lubricating‐oil pressure acting on a spring‐pressed piston 46 moves a control valve, formed by a stem 41 having enlarged parts 44, 45 into the position shown in Fig. 1, to permit the fuel discharged by the pump piston 10 to be delivered through a conduit 30 to a fuel nozzle 32. When the engine stops, the oil pressure falls and the spring 50 moves the piston 46 to the left until it engages an abutment 51. In this position, the enlarged part 45 closes the conduit 30, and the enlarged part 44 uncovers a conduit 40 connected to the float chamber 15 so that if the throttle is now opened, the fuel discharged by the pump is returned to the float chamber. The piston 46 may be replaced by a diaphragm and may be operated by the suction, or in a supercharged engine by the pressure, in the induction system. The provisional Specification states that the control valve may be disposed between the float chamber and the pump.