FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1974
1974 - 0296.PDF
266 ALPHA JET ment system is effective. France has the lead, but ensures joint decisions. The executive agency representing DTCA and BWB is responsible only to a steering committee at ministry level, which reports to its governments twice per year. The manufacturers' integrated design team has been managed at company level by a dozen-strong management team. Neither company nor government management has been allowed to sprout more than the absolute minimum of sub-committees. Alongside the design activity have been the service teams, called "equipes de marque", made up of Service experts in operations and support who have moni tored the design and are preparing for acceptance, intro duction into operation and subsequent support of the air craft. A separate German team looks after the CAS and Luftwaffe aspects. Germany has followed an established pattern and appointed Dornier as logistics manager for its Aloha Jets in service. The basic Alpha Jet airframe was kept rigorously simple, despite its relatively high performance. The speed range of lOOkt to 500kt was to be covered with fixed leading edges, no unconventional lift devices and fixed intakes. Fully powered controls are necessary, with consequent dual hydraulic systems and an 'Arthur" load-factor limiting, dynamic feel system, but the surfaces are conventional with slab tailplane and simple ailerons. The electrical system includes two 28V starter-generators and two in verters to produce 115V, 400Hz power for avionics. Engine starring is by internal power. A mission need not be abandoned if an inverter or generator fails. The liquid oxygen system has ten hours' endurance and requires filling only once per day. Refuelling is under pressure at a single point. The crew can enter and leave without ladders. The Alpha Jet concept is to achieve ten- minute turn-rounds with minimum ground equipment. Overall maintenance man-hours are 734 per flight hour for the first 3,600hr flying. The pressurisation system is designed to maintain a comfortable atmosphere for training, with 2,000m, 6,600ft cabin pressure maintained to 5,600m, 18,400ft altitude and a differential of 4 351b/sq in thereafter. The undercarriage is stressed to accept a touchdown descent rate of ll-8ft/sec, 3-6m/sec on rough ground in the training role and its 8ft llin, 2-71m track is sufficient to cope with the high e.g. and high wing. All three legs retract forwards, so that slipstream assists the emergency extension system. The mainwheels turn to lie flat under the intake ducts and the nosewheel is offset to starboard and turns to lie at an angle inside the tapering nose cone. The fuel system is divided for right and left engines, based on groups of integral tanks in the wing torsion box and the fuselage. For aerodynamic design, Dassault-Breguet and Dornier made full use of their computer design systems, particu larly the "three-dimensional" technique developed by Dassault. By this means, the aerodynamic calculations could be translated into computer-defined contours and. where appropriate, even transferred direct to numerically con trolled milling machines. The aerodynamic shape follows the area rule, though a sharp drag rise above Mach 0-85 is claimed as a safety feature. The Alpha Jet is subsonic. A dozen models of various scales were tested in ten wind tunnels all over Europe, the final example being a flutter model. The wing has a leading-edge sweep angle of 31° at the root and 34° at the tip, 10 per cent t/c ratio at root and 8'6 per cent at tip, with six degrees anhedral. Structure is a torsion box based on machined spars, ribs and copy- milled skins, the assembly bolted together and sealed to form integral tanks in each half-span and in the carry- through box. It proved possible to continue design of the leading-edge contour even while the torsion box com ponents were being milled, so that final decision on contour could be based on the maximum of model testing and com puter-aided design. The leading-edge dog-tooth location FLIGHT International, 28 February 1974 has been shifted some inches outboard since the first flight of the 01 prototype. High-lift devices consist simply of double-slotted trailing edge flaps. The slab tailplane is a downward-lifting section of 30° sweep with a nine degree anhedral, designed to bring it into smooth air beneath the wing wake at high angles of attack. The fin is positioned considerably ahead of the tailplane for good spin recovery. Wash-out and dog-tooth on the wing are certainly designed for the same good be haviour which is essential for the training role. In-flight braking is provided by two surfaces opening above the rear fuselage ahead of the fin. The whole structure is stressed for 12g ultimate loading, and for manoeuvres at combat weight ranging from +8-6g to — 4-6g. Typical of the pressure behind all Dassault-Breguet de velopment work is the use of the Samuel flight test instru mentation system at Istres. Recording and telemetry pack age in the aircraft transmits flight measurements in real time to a receiver and processing system on the ground, with displays by which flight-test engineers can observe re sults and comment to the pilot by radio. Every second of flying is therefore useful and the flight envelope can be extended during a test flight. A number of joint Franco-German teams have been formed to supply equipment for Alpha Jet, although the continued on page 277 ALPHA JET DATA Dimensions Wing span Length Height Wing area Wing sweep at quarter chord Wing loading Thrust/weight ratio at combat weight Wheel track Weights Weight empty, with crew Max internal fuel Training T/O weight Max T/O weight Combat weight Landing weight Max landing weight Max external load External fuel Performance Max speed at s.l. Endurance, max fuel Radius of action, hi-lo-hi, 5min combat Ferry range with drop tanks Service ceiling T/O at 10,7801b, 4,890kg T/O at 15,3401b, 7,000kg T/O to 50ft at 10,7801b, 4,890kg Landing at 8,1301b, 3,690kg Approach at 8,1301b, 3,690kg Approach at 11,0201b, 5,000kg Touchdown at 8,1301b, 3,690kg Touchdown at 11,0201b, 5,000kg Max g in steady turn at s.l. Max g in steady turn at 36,000ft, 10,970m Time to height Initial climb rate Engine-out climb rate Powerplant 29ft 11 in 40ft 3in 13ft 9in 188 sq ft 26b 57-2lb/sq ft 0-7 : 8ft llin 7,6601b 3,1201b 10,7801b 15,3401b 8,6401b 8,1301b 11,0201b 4,9351b 1,1401b 535kt 2hr at s 9-11m 12-29m 4'19m 17-5m2 279kg/m2 1 2-71m 3,475kg 1,415kg 4,890kg 7,000kg 3,920kg 3,690kg 5,000kg 2,235kg 520kg 991km/hr I. 3hr at altitude 340 n.m. 1,650 n.m. 45,000ft 1,580ft 3,800ft 2,500ft 1,710ft 120kt 137kt 102kt 116kt 6-5g 1-8g 8min to 36,000ft 11,800ft/min 1,670ft/min Two Turbomeca Larzac 04 turbofans Static thrust s.f.c. at take-off thrust Bypass ratio 2,9701 b 630km 3,057km 14,000m 480 m 1,150m 760m 520m 222km/hr 254km/hr 189km/hr 215km/hr 10,970m 59m/sec 8-5m/sec 13-25kN 0-72lb/lb/hr 1-13 :1
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
