M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)

Журнал Flight

Flight, July 13, 1916.

CONSTRUCTIONAL PROGRESS AT THE RUFFY-BAUMANN SCHOOL OF FLYING.

   APART from the hard usage of a machine engaged on actual war service, it is doubtful whether there exists any form of work which tests a machine more severely than that to which it is subjected at a flying school. For this reason it is a matter of some interest to follow the evolution of the various details of a school machine even if its general design follows closely along standard lines. A case in point is the school type of machine built and flown at the Ruffy-Baumann school of flying at Hendon. Although these machines are admittedly of the Caudron type - a type, by the way, which has proved itself through a number of years exceptionally suitable for instruction purposes - following closely along the lines of the original machine, a close inspection soon reveals a number of detail alterations, suggested by years of experience in school work. Some of these alterations are in the nature of strengthening up parts which, although standing up well to stresses imposed in ordinary flying, have been found somewhat liable to give way under the severe treatment frequently meted out to a machine at the hands of a beginner in the gentle art of flying, while others have been made with the object of improvement from the point of view of quickness and cheapness of manufacture rather than from one of constructional strength.
   In the accompanying photographs and sketches some of the constructional details of the Ruffy-Baumann biplanes are illustrated, giving a better idea than is possible by means of a written description of the various fittings and parts employed. As the new 60 h.p. two-seater is the latest type, this has been chosen for purposes of illustration. On inspecting the machine, one of the first things one notices is the fact that the nacelle, instead of being mounted on stepped struts some little distance above the lower wing, rests with its lower longerons on the spars of this, being attached to the inner plane struts by bolts in the manner shown in one of the accompanying sketches. This gives a somewhat deeper body of rather better shape than the old one, and the cowl round the Gnome engine forms a fairly good entry for the air.
   As dual control is fitted on all the machines built by the Ruffy-Baumann school, the rear engine bracing has been somewhat modified in order to provide room for the front foot bar, which, as one of our sketches shows, is in the form of a steel bar, bent to form a step into which fits the pilot's foot. Since the two bracing rods running from the rear engine bearer would have formed an obstruction to the free movement of the foot bar, they are no longer taken lo the lower corners of the nacelle, but to a point some little distance inside the corners as shown, and since this throws a bending strain on the horizontal strut, that member has been reinforced with a length of channel steel, drilled for lightness. A further alteration differing from standard practice in regard to the rear engine support will be noticed in the illustration. Instead of the usual flanged collar on the induction pipe, to which the bracing rods are attached by means of forked ends, there is a wide collar turned out of a solid steel bar. In this collar are drilled a number of holes a short distance inside the outer edge of the collar, in which are accommodated hemispherical nuts, internally threaded to receive the inner ends of the bracing rods. The arrangement will be clear from the inset in the larger sketch. It will be seen that in this manner a universal joint is formed, so that a slight discrepancy in the alignment of the attachment of the outer ends of the bracing rods and the flanged collar on the engine shaft will not be of any consequence.
   With regard to some of the fittings illustrated little need be said, as the sketches are, we think, self-explanatory. The strut sockets are welded to a wiring plate secured by two bolts passing through the spar, and in the case of the point of attachment of the front skid struts these, it will be seen, no longer have square ends abutting on the flat of the front spar, but fit into sockets welded to a common base plate, thus practically being proof against any tendency to slip sideways along the spar. The diagonal bracing struts running from the lower ends of the interplane struts to the extensions of the top plane are no longer made of a steel tube with forked ends, enclosed in a fairing of wood, but are made up of solid spruce, and fitted at the ends with a socket passing over and pivoted to an eyebolt.
   One of the features noticed when looking over this machine is the arrangement of the shock absorbers, which gives the impression of being very simple and substantial. Instead of the usual round rubber cord, rectangular section rubber rings are used, each ring passing over two transverse bolts, of which one is held in the lower plate passing around the skid, while the other is secured to the two T-shaped flanged steel plates attached to and, of course, moving with, the wheel axle. In case of a heavy landing one or more of the rubber rings may be broken, but the replacement of a ring or two is an operation occupying a few minutes only, and costing very little. On the other hand, when a rubber cord breaks it usually means either a new cord or an unsightly knot in the old one.
   Perhaps one of the most interesting, and certainly one of the least apparent, features of the Ruffy-Baumann biplanes is the method of selecting each rib for the particular work it has to do. In other words, progressing from the wing-tips towards the centre, consecutive ribs are less elastic than the one preceding, so that at the tip, where less load is carried, the ribs are weaker, gradually increasing in rigidity towards the centre. The consequence is that when the machine is flying, the trailing edge of the whole wing forms a straight line instead of bending down in the neighbourhood of the tail booms and up as the tip is approached. There can be little doubt that this form of construction has a very important bearing on the performance of the machine.
   At present there are five biplanes, all fitted with dual control and having Gnome engines of 50 and 60 h.p., in commission at the firm's school at Hendon, where extra accommodation in the form of a large tent has been provided. It might be mentioned that it is only lack of housing space that limits the number of machines, and already a similar number are waiting to be erected at the firm's works at The Burroughs, Hendon. On a recent visit to the works we found workmen busy making foundations for machinery and digging pits for the shafting, and we understand that as soon as delivery can be obtained a number of wood-working machines of various types will be installed, when the output of machines should be greatly accelerated. As a matter of fact, considering the facilities, or rather lack of them, at this firm's disposal in the past, they have turned out the machines at a very good pace, and when the new machinery has been put in, which should be in a week or two, the output will be more than equal to the requirements of the school, leaving a margin for any outside orders that may come along.