FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1963
1963 - 0495.PDF
FLIGHT International, 4 April 1963 BUCCANEER... Hliffo Transport Publications Ltd 1963 This underside view of the Buccaneer S.I is complementary to the main illustration on pages 470-472; it clarifies several features and shows numerous details not visible in the larger drawing, and employs common key numbers the take-off case, with landing a close second. The resulting shape was suitable for low-level flight at high subsonic speed. Several factors made two engines a logical choice. Most of the rival NA.39 submissions used Avon or Sapphire turbojets. but Blackburn's was small enough to employ the much lighter Gyron Junior. This exactly met the thrust requirement for high speed cruise, and was specially adapted to provide the tremendous air bleed needed by this application. During the early jet-deflection studies the engines were located forward of the wing box, and this position was adhered to to minimize structural problems. It was at this time that the whole aircraft was area-ruled to re duce drag at high Mach numbers. This increased the volume avail able inside the rear fuselage, and much additional equipment was located here in order to release other regions for fuel. To meet the dive-attack case, airbrakes of extreme effectiveness had to be provided. After investigating a profusion of possible schemes, Blackburn decided to employ a pair of clamshell petals forming the entire rear end of the fuselage. When open, these airbrakes greatly increase profile drag, and this improves handling qualities at VMD by balancing out the induced-drag increment resulting from the use of the high-lift blowing system. In turn, this airbrake dictated a high tailplane. Having sorted out the basic aircraft layout, Blackburn turned their attention to the structural design. It was apparent from the outset that the operational life of the aircraft would be an exceptionally arduous one, and fatigue appeared to pose formidable problems. Ten years ago even less was known about the fundamental mechan ism of fatigue than is known today, but the philosophy adopted was sound: to avoid all stress concentrations, pay attention to surface finish and hold the number of major and minor joints to an absolute minimum. These ends were well served by manufacturing skins from machined sheet with integral stiffening, and spars and ribs from single forgings. Both these methods were then being widely introduced into US military aircraft. The Americans had gone for three-dimensional machining, but Blackburn undertook an exhaustive study into the economics of alternative methods and decided that the advantage lay overwhelmingly with flat-machined planks which could later be formed to the desired profile. . No skin mill of the calibre required existed in this country, and Blackburn eventually decided to produce their own. Four large cam-controlled millers were built at Brough, and these have since produced all the skins for wings and tailplanes. Where integral machining could not be employed, stretch-formed plate was turned out by a large Hufford stretch press obtained from the US by the Ministry of Supply. Most of the "spiders," spar rings and wing-root fittings were stressed severely enough to be in high-tensile steel, but the rest of the primary structure was designed in high-strength aluminium alloys with good fatigue properties, and all large billets were initially obtained from the US. Integrally machined skins and fittings were produced to close tolerance and carefully polished, and large stretched plates were chemically etched to reduce weight. The structure was further refined to reduce weight in the eighth deve lopment machine and subsequent aircraft. In the main, scantlings were dictated not by strength but by stiffness, despite the fact that the whole structure was designed to very high factors (an ultimate of 12 at combat weight). Extensive flutter testing was carried put in a NASA tunnel at Langley Field, under MWDP, and in the company's own 27in tunnel later built at Brough. Immense research was necessary to perfect the new techniques involved in the structure and blowing system, and to find the optimum materials. In the design of the flying controls there were three principal problems: stiffness; control power (actuator thrust); and sensitivity and feel. The arrangement finally adopted is discussed in the appropriate section of the description which follows. Eight months after they submitted their brochure Blackburn Aircraft were told they had won over their rivals, and an order for a development batch of 20 aircraft followed. The first machine was taken by road to the RAE, Bedford, where it flew in April 1958. The type subsequently received the name of Buccaneer, and the first production version, bearing the designation Buccaneer S.l, is now serving both ashore and afloat with the Royal Navy. The following description applies solely to this version of the aircraft; it is followed by a review of subsequent developments. Airframe Structurally, the fuselage is divided into five sections: folding nose; cockpit, centre fuselage; rear fuselage; and airbrake. The extreme nose is a pointed and pressurized randome of glasscloth laminates, covered with an erosion-resistant neoprene skin. It is secured by toggle fasteners to a conventional light-alloy section which may be manually unlocked, folded to port and secured by a jury strut against the side of the fuselage.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
