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Aviation History
1954
1954 - 0445.PDF
19 February 1954 205 ANALYSING the BEVERLEY R.Ae.S. Brough Branch Hears Lectures on Design, Production and Flight-testing AT the R.Ae.S. Brough branch meeting held in Hull on /% February 3rd, three executives of Blackburn and General Aircraft Ltd., each lectured on one aspect of the Beverley. First to speak was Mr. C. W. Prower, assistant chief designer, who discussed the specifications and design history of the aircraft. Designing the Beverley. Mr. Prower began by saying that as the aircraft had first been ordered to a military specification he would deal initially with military requirements. Of these there were two, the strategic and the tactical. The former called for the transporting of military stores and personnel from one theatre of operations to another. Here air transport was a vital factor, because of the number of fighting troops which would otherwise be held ineffectively in transit by other methods of transport. This country had no strategic air transport as such, and the Beverley could fill the gap. Tactical transport required the movement of men, equipment and supplies right into the forward areas where no proper airfields might already exist. The Beverley was originally conceived, during the war, for such missions. Gliders used in war-time were now considered too cumber some, and at the time of the first Beverley design-studies the technique of parachuting really heavy items of equipment had not been developed. The original design therefore provided for the aircraft to be powered by four Merlin 90s, carry a payload of 20,000 lb and weigh 75,000 lb all up. The load was to be carried in a container with its own undercarriage (tracked) and long-travel shock-absorbers. The aircraft was to fly slowly over the dropping zone at a height of a few feet and release the container, which would subsequently be brought to a standstill by very powerful automatic brakes. Alternatively, since such an operation demanded too much of the pilot under operational conditions, the container was to be dropped under a cluster of parachutes. A parachute-drop at this weight, however, had not yet been achieved, even nine years after the design proposal. The next design submitted was for a 20,000 lb payload and four Hercules 100s, but this was enlarged to 38,000 lb payload, four Centaurus, 500 miles range and an a.u.w. of 126,000 lb. The undercarriage was tracked and arranged to be semi-retractable both in the air and on the ground. The wing was larger than the Beverley's, as the performance was to be equivalent to that of a glider. Heavy parachuting was still some way off. This design also was discarded, because of its size and expense. By the end of 1945 requirements began to crystallize and a specification was finally issued for what was now known as the Freighter I prototype; payload 25,000 lb and still-air range 500 miles, equivalent to an effective range of only 250 miles. It was to be a tactical transport with fixed undercarriage, low wing-loading and braking airscrews, suitable for trooping, parachuting, casualty evacuation, glider towing and heavy parachuting. Bristols de veloped a two-stage supercharger Hercules to meet the required ceiling of 18,000ft; a wing loading of 30 lb/sq ft and span of 162ft were chosen, with large-chord N.A.C.A.-section flaps. The braking airscrews were to enable it to land fully loaded in any space from which it could take off at light load. Heavy parachuting was achieved with the aid of a series of special containers suspended from a ceiling gantry. An electric motor and endless chain were eventually to unload them through the stern door. Estimated changes of trim indicated that two large items weighing 9,000 lb each could be dropped safely in quick succession. Provision was also made for the carriage of twenty-four 300 lb airborne supply containers beneath the fuselage. Components for two prototypes were made at Feltham and one aircraft assembled at Brough for its first flight, which took place on June 20th, 1950. The other parts were stored. The bogey undercarriage which has become standard was experimentally fitted in 1951. Subsequent developments, principally in parachuting, meant that the all-up weight could be increased without enlarging the airframe; that landing in unprepared forward fields would prove unnecessary, because airfield-construction equipment could be parachuted in first; and, finally, that sufficient endurance would be required to return to the take-off point after each mission. These modifications led logically to the second prototype, which thus acquired the advantages that it went some way towards providing a strategic transport and that in the civil version, it would show a large reduction in operating cost per ton-mile. Civil applications had, of course, been constantly kept in mind throughout the programme. American development of the floor-roller system of cargo-dropping allowed a further increase of payload, space for which was found in the tail boom, where a passenger/troop compartment was arranged. The tail boom was also tilted upwards slightly to keep the tailplane clear of slipstream in the climbing attitude. The airscrews of the second prototype were restricted to 14ft 6in diameter, because the engine spacing was for Hercules engines. The full 16ft 6in diameter would in due course increase performance. Structurally the Beverley was quite conventional, although materials and dimensions had to be carefully studied to avoid un necessary weight-penalties. The floor was one of the strongest yet fitted in an aircraft. Furthermore, all known precautions had been taken against fatigue troubles, the weight penalty involved being considered worth-while in view of subsequent economies in operation. Discussing flying controls, Mr. Prower said that it was almost impossible to balance them sufficiently for the pilot to operate them without risking overbalance in certain flight conditions. Of the alternative of powered controls or a servo-tab system, the former were chosen because of the lack of experience in the latter at the time. "Feel" in the power system was provided by partial feed-back of control forces. Performance figures were still subject to security, the lecturer said, but he was able to give estimates for the Universal, the Beverley's civil counterpart. The aircraft was designed for alter native loads and ranges (at a cruising speed of 185 m.p.h.) of 47,000 lb and 200 miles or 30,000 lb and 1,200 miles. By contrast many aircraft in use today were unable to make up their maximum a.u.w. with payload when carrying fuel for short ranges. The Universal was designed for operation from 1,350 yd unpaved runways, including all reserves for engine failure on take-off. Either 122 passengers, or freight in special pre-packed containers (reducing turn-round time) were envisaged. In concluding, Mr. Prower hinted at further developments, particularly regarding the installation of different power-plants, and the fitting of a retractable undercarriage for economy over the longer stage-lengths. Production. The next thirty minutes of the meeting were devoted to a paper by Mr. W. A. Hargreaves, works manager, on the production of the Beverley. In the short time allowed he proposed to deal only with the production planning phase of the programme as opposed to the actual construction side. He described his task basically as the realization of the de signer's ideas in the final production aircraft. In this process, he said, the whole design and production staff had to act as a team, from the designer to the test pilot; furthermore, the customer's requirements and criticisms had to be taken into account. "No ideas," he said, "have any real value until the result has been turned into an article which the customer is ready to buy, and at a price which he is willing to pay." Again, in view of the military side of the contract, it was not possible to mention any precise figures, and he would have to confine himself to an indication of trends and methods. The basic principles of production could be enumerated as follows: (1) The production of any item called for four basic factors: men, materials, floor space and tools. (2) However com plex, any product such as the Freighter could be broken down into a number of detailed items. (3) Details must be fabricated into sub-assemblies, then into assemblies, units and finished products, these processes being closely co-ordinated according to a strict timetable. The first requirement in the planning stage of a contract was for a timetable for the assembly of all components, and for the integration of the timetable with the overall programme. This programme was determined by the intended rate of production in aircraft per month, the date of commencement of deliveries and the time taken to achieve peak production. The lecturer's department had met with some difficulty in this respect because of the size of the aircraft; no effective comparison with schedules previously employed could be made. Experience with the first prototype was therefore used, together with figures from war-time production of Sunderlands. Comparisons led to
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