FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1952
1952 - 0654.PDF
•006 296 •ooa 100,000 300,000 300,000 400,000 600,000 CROSS WEIGHT lb Ratio of profile drag to all-up weight, plotted against the weight of modern designs of flying-boat. Proposed design for an ocean-patrol flying-boat, weighing approximately 150,000 lb and (towered with four compounded diesel engines. THE FUTURE OF THE FLYING-BOAT able hull design it had been found possible to alight safely in seas up to 9ft from trough to crest. A considerable amount of research information on accelerations and local impact pressures had been accumulated over many years, but recently the application of strain-gauging and the recording oscillograph had made it possible to measure transient stresses and accelerations with accuracy. Full-scale impact acceleration measurements had been made, using the latest form of instrumen tation, both in calm and rough water, to check the magnitude of peak accelerations, and this had supplied data for comparison with theory. In the United Kingdom, as a result of joint investigation made by the Royal Aircraft Establishment, the Marine Aircraft Experimental Establishment and the Saunders-Roe Company, theoretical estimates of peak accelerations had been made which gave values agreeing well with full-scale results. Mr. Knowler summarized his views on the subject of structural weight by remarking that there was so far no evidence to indicate when increase in size of aircraft, particularly flying-boats, would be accompanied by an increase in the structural weight percentage. Arguments had been advanced recently claiming that adverse scale laws applied to the specific power weight of turbine engines. This might be theoretically correct, but it was thought that technicians were following the same erroneous conclusions which has so effectively been refuted in connection with structure weight. This statement, it must be admitted, was based on a statistical examination of the subject, but the conclusion was clear that, taking into account the technical improvements which were con tinually being made, the specific weight of all types of engine showed improvement with increase in power. This was an important consideration in connection with the future of large aircraft. The fact that a growth in size did not entail a greater structure weight percentage did not alone justify large aircraft: the real justification arose from the gain in aerodynamic efficiency which resulted from increasing size. Discussing maintenance and docking, the lecturer said that the tradition that flying-boats should lie at moorings for refuelling, inter-flight maintenance and loading died hard. His own views on types of base facilities were summarized as follows: (i) Maintenance base. All major overhaul work should be done at this base; there fore, it would have a slipway, hard-standing, hangars and stores. It would also have a number of permanent pontoon docks with all necessary supplies piped from the shore, (ii) Operating bases. All regular operating or refuelling points would be provided with a number of portable pontoon docks, having causeways to the shore Design for a transonic intruder /bomber flying-boat, described by Mr. Knowler as the logical development of aircraft such as the S.R. /A.1. carrying piped supply-lines for refuelling, electrical supplies and so on. They would, however, carry emergency equipment for engine changing, (iii) Temporary refuelling bases. These would be similar to the operating bases but would be equipped with a single portable pontoon dock. The dock would be used with either a floating causeway to the shore, where this was possible, with land-based refuelling storage and equipment, or from a barge moored nearby, (iv) Emergency bases. These would be used infre quently and need not be equipped with more than fuel storage and means of supply. The aircraft would lie to a mooring buoy and be tendered by a local launch. Fuel would be pumped from a small lighter. At this point Mr. Knowler looked further to the future. It would be apparent, he said, that hydrodynamic and technological development had made great strides in the past few years but, this knowledge had outstripped design application. To take full advantage of the flying-boat's unique facility for operation away from prepared bases special consideration must be given to ensure that the minimum of outside assistance was necessary for refuelling, rearming and inter-flight maintenance. By special design, the flying-boat's capabilities of landing on the open sea could be improved upon so that this possibility could be included in the military duties laid down. Long range was one of the flying- boat's most valuable assets, and increased range could be regarded as attainable on future classes of aircraft, including ocean-patrol boats and trans-ocean transports, both military and civil. These long-range types would almost certainly use airscrews. Mr. Knowler now briefly discussed jet propulsion, turboprops and piston engines, and referred to the Napier Nomad, which con sisted of a compression-ignition diesel, the exhaust from which drove a turbine coupled to an axial-compressor, which in turn supercharged the diesel. In addition* the surplus power from the turbine supplemented the main shaft output. This type of engine, he said, was particularly suitable for ocean patrol flying-boats, which were required to operate over a wide range of altitude and speed. The operation of intruder/bomber squadrons from remote quarters of the world was now being considered. By the use of improvised bases the radius of action necessary could be reduced to distances which would permit the design to be primarily for speed, and with present knowledge, this might be in the transonic region. The water-based fighter had been brought into the field of military strategy and was capable of operation both from distant locations and also for home defence, where the indestructibility of the runways was a consideration in future defensive planning. The speed of this type of aircraft was not limited in any way by its water characteristics and machines in the supersonic class could be considered. Of ocean-patrol flying-boats Mr. Knowler said that no doubt new methods of submarine detection would be developed in the near future, in addition to radar and sonobuoy location. For example, it had been suggested that such flying-boats should alight at sea, lying to a sea anchor, while sub-surface methods of detec tion were employed. This brought into prominence the high sea- Operating costs for different engines (no wind)—curves constructed for similar aircraft designed for optimum ^efficiency over varying distances, their size being adjusted accordingly. 15 TU RBOPHC )P •* £i JET 1 ^ 'ISTON COMP DIE OUND SEL 12 3 4 5 STAGE DISTANCE (milci x 1,000)
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
