FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1957
1957 - 0687.PDF
FLIGHT, 24 May 1957 693 CRUSADER . . . factoring research worked closely to develop the necessary data for usingthis material, and this resulted in almost 50 different high-strength parts being incorporated on the airplane. Here again, excessive parts andweight are eliminated at a cost commensurate with the policies estab- lished at the start of the design." Most of the jigging for major airframe components is fabricatedfrom heavy steel tubing. The whole of the Dallas F8U assembly area, measuring 1,200ft by 200ft, was reproduced in model formto a scale of 1/96, correct even to the time clocks on the walls. Every jig and fixture was reproduced by a model and, after someof the jigs had been redesigned four times, the optimum floor layout was agreed. The saving in initial time was considerablesince many of the largest jigs turned the scale at almost 30 tons. Even today the miniature assembly area is helping to develop newfixtures and in the revision of'the existing space to meet increased rates of production.Heart of the aircraft is the centre fuselage, conventionally made from light alloy. The cross section is basically rectangular, thedepth being over 6ft. Frames and bulkheads are generally pressed from heavy plate in left and right halves joined at the topand botto-n centre-lines and stabilized by radial angle sections riveted on. Along the bottom runs a heavy keel member with avertical web, extruded booms and vertical angle stiffeners along each side. The lower part of the centre fuselage is largely occupiedby boxes for the retracted main undercarriage, the rest of the space being occupied by fuel cells and the intake duct, the latter beingof basically circular section in this region. The fuel cells are of the bag type, and Chance Vought employ precision acceptance jigsmade from half-inch Plexiglas sheet in order to check that the tank fittings will locate correctly in their appropriate airframe bays.The latter do not permit visual inspection when the cell is installed. Last week a $5m contract was signed under the terms ofwhich North American Aviation's Columbus, Ohio, division will make centre fuselages for Dallas. Both the fore and aft fuselage sections are finished as largelyequipped units before being joined. The front fuselage incor- porates the subtly profiled intake duct, which rises immediatelybehind the cockpit to clear the nose-undercarriage box. Part of the duct consists of a large light-alloy precision casting, withintegral stiffening flanges which save a great amount of weight and manufacturing time compared with a fabricated assembly. 1 2 7" -TT_- Typical sealing of in- tegral-tank wing: 1, countersunk skin rivet with Riv-O-Seal; 2, CD- ring; 3, PK screw in sealant-injection hole; 4, PR-702 sealant; 5, aluminium shim; 6, Stat- O-Seal washer; 7, fuel. The pressurized cockpit sits directly above the duct and occupiesa considerable axial length. It is enclosed by a clam-shell canopy made from four magnesium castings: front hoop, rear hoop andhinges, and left and right box-section rails with integral locking lugs. Two more precision castings in the same material formthe frame of the windshield. Most of the rear fuselage is occupied by the powerplant, andthe structure is largely of titanium supplied by Rem-Cru or Mallory-Sharon. The sting-typc arrester hook is attached to aforged anchor on a strong frame at the front of this section, and other frames bear the powerplant and anchorages for the hori-zontal tail. In the F8U-1P photographic aircraft the lower part of the fuselage houses the automatic camera installation, and inlate-production machines the rear section also carries two diagonal ventral stabilizing fins. .A multi-spar structure is followed throughout the wing. The centre span, of the same width as the fuselage, serves only as abeam, hinged to the fuselage at its rear edge and joining the port and starboard aerofoils. On the starboard side at the front trans-verse member of this structure is the single wing actuator. The latter is a two-position, self-locking Aeroproducts hydraulic ram,stressed to accept tensile loads since the wing c.p. is often ahead of the hinge axis. The ram has a single pivot at its lower end and auniversal joint where it meets the wing. The wing-pivots them- selves are steel multi-fork fittings.Each inboard wing is an integral tank. Chance Vought were from the outset well aware of the extreme difficulty of achievingcomplete success with an integral tank of supersonic profile, and they adopted as their doctrine "first make a fuel container; thenmake it behave like a wing." An accompanying diagram indicates typical sealing methods. Mating faces are secured by rows ofcarefully positioned rivets sealed as shown. In addition, all ribs and spars have O.125in-radius axial grooves adjacent to the skininto which PR-702 sealant is forced at high pressure from injection holes spaced 3in apart along the skin, the latter being blanked offby self-tapping PK screws. Fuel is also contained in the outer panels, which are hinged tothe inboard sections by multi-fork fittings machined from high- tensile steel. Wing folding is accomplished by a single jack ateach fold which pulls the outer panels directly upwards and locks them in the folded position, additional manual locking being pro-vided for protracted parking. As already noted, the entire leading edge is arranged to droop.The inner and outer sections are mechanically independent, and hinge downwards through different angular displacements. Two-position Sargent hydraulic rams push the surfaces down and lock them in the position selected. All four rams are arranged along aline parallel to the leading edge, and operate a mechanical linkage with precision-cast bell-crank assemblies. No movable trailing-edge surfaces are fitted to the outer wings.The inner wings each carry two sections of ailavator, comprising ailerons which are arranged to droop at low air-speeds, and inner-most sections employed as flaps for landing. The actuators are mounted behind the wing boxes and operate through short link-ages. The gaps between the aileron ends and the outer wings are sealed by Connecticut Hard Rubber extrusions of a curious"three-fingered" section. Tail volume is considerable. The vertical surface has three prin-cipal spars and incorporates much magnesium skinning. A single jack mounted vertically within the fin actuates the rudder, whichabuts a rub-type sealing strip at the leading edge. Left and right tailplane slabs are independent surfaces cantilevered from largetrunnions in the rear fuselage. Immediately above each anchorage is an actuator package—again by Sargent—comprising a groupedassembly of jack, valves and feed-back mechanism. The whole unit is bared by removing a single panel; less than a dozen boltsand pipe-connections need be broken to remove the unit and replace it by another package previously adjusted on the bench. The small and simple design of landing gear is one of the greatestadvantages of the variable-incidence wing, since the fuselage can sit close to the ground in a level attitude during take-off and land-ing. Each main gear comprises a compression strut and a tension strut, both hinged to the same fuselage frame. On the end of thevee thus formed is mounted a Goodyear forged magnesium wheel, and the whole unit is simply pushed forwards by a long-strokeram anchored to the apex of the vee and to a fuselage frame at the other end. The wheel remains perpendicular to the legs andis thus housed in a diagonal position. Goodyear tubeless tyres and dual-disc brakes are fitted. The nose-gear has a single legcarrying two forged magnesium beams which provide levered suspension. The unit retracts rearwards into an unpressurizedbox, the top of the leg above the pivot being pushed forward by a long-stroke ram mounted well aft on the port side of the bay. For catapulting, a strop attachment is provided on the mainkeel member on the centre-line of the aircraft. The attachment lies above the speed brake, and the latter surface therefore has alarge notch cut-out to permit the strop to be hooked on. The fact that the attachment is only 2ft from the deck is an advantage. In the first batch of F8Us the engine is a Pratt and WhitneyJ57-P-4, but the more powerful P-12 is now usual. This series (Continued after double-page drawing, overleaf, of the Crusader)
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
