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Aviation History
1959
1959 - 0803.PDF
TTTT 398 FLIGHT Snecma A tar 9. Military single-shaft turbojet with afterburner. Nine-stage compressor, annular combustion chamber with 20 burners in individual cups, two-stage turbine and variable-augmentation afterburner with three-position nozzle. Max diameter over turbine casing, 33.86in; overall length as depicted, 3?63.8in; dry weight, 2,755 Ib; max ratings, 13,228 Ib at 8,400 r.p.m. with full reheat (s.f.c. 2.075), 11,905 Ib with partial reheat (s.f.c. 1.7) or 9,370 Ib dry (s.f.c. 1.1), with mass flow and pressure ratio of 149.9 Ib/sec and 5.5:1. The Atar 8, without afterburner, weighs 2,028 Ib and is rated at 9,700 Ib dry with s.f.c. of 0.98. Turbomeca Arbizon. Single-shaft turbojet. Single transonic axial compressor stage followed by single centrifugal stage, annular combustion chamber and two-stage turbine. Overall height, 19.9in; overall width, 16.4in: dry weight. 230 Ib; max thrust. 550 Ib at 34,000 r.p.m. with s.f.c. of 0.92 (max cont., 440 Ib). SNECMA Super Atar (provisional drawing). Military single-shaft turbojet. Axial compressor with about five stages, with variable-incidence inlet guide vanes and first two stators, annular combustion chamber, two-stage turbine and large afterburner with fully variable convergent/divergent nozzle. Overall diameter at intake, 37in; approximate overall length as depicted, 210in; dry weight, probably about 3,700 Ib; max rating, about 22,000 Ib with reheat with mass flow and pressure ratio of about 325 Ib/sec and 6:1. AERO ENGINES 1959 . . . (600-625 h.p.) and, under Bristol licence, the Hercules 759 radial (2,040 h.p.). The major development and production has centred upon the Atar family of single-shaft turbojets. The latter, and the new Super Atar, are commented upon below. Atar A brief history of this simple and reliable axial engine was given in our July 26, 1957, issue. The first version to enter produc- tion, in 1953, was the Atar 101 D-l, rated at 6,610 Ib dry and used in the Mystere II (France, India and Israel). The 101 E, of 7,716 lb rating, has been made in great numbers for the Sud Vatour and for such machines as the Baroudeur, Griffon, Leduc O.22 and, in a special form, the Atar Volant. Some hundreds of Atar 101 G-series engines have followed, rated at 9,700 lb with reheat, for the Dassault Super Mystere B.2, and for various other high- speed aircraft. The Atar D had a seven-stage compressor, but a zero-stage was added in the E and retained in the G. A further "zero-zero" stage, together with a second turbine stage, were added in the next series, the Atar 8 and 9. These new Atars are virtually completely redesigned, and give very much higher thrust up to Mach numbers well beyond unity. The new compressor, which operates at a pressure ratio of 5.5 (compared with 4.8 of the earlier Atar E/G), has 1,335 blades, those of stages 2 to 6 (rotor) or 3 to 6 (stator) being of light alloy and the remainder being steel. The Atar 8, the first of the revised engines, weighs 2,180 lb, has a dry rating of 9,700 lb with s.f.c. of 0.98, and is in production as the powerplant of the Dassault Etendard IV M carrier-based fighters. The Atar 9, illustrated, powers the Dassault Mirage IIIA and has already flown at more than Mach 2.2. Super Atar At present this engine remains largely shrouded in secrecy, since it is neces- sarily being developed to a fairly long-term time scale. Although bearing the name Atar it Turbomeca Astazou. Single-shaft turboprop. Single transonic axial compressor stage followed by single centrifugal stage, annular combustion chamber and multi-stage turbine. Overall diameter, 18.1 in; length as shown, about 69in; dry weight, 245 Ib; mass flow and pressure ratio, not available; max rating, 320 h.p. at unstated r.p.m. with s.f.c. of 0.72 (this power is limited by reduction-gear capacity and is available up to 92 deg F, or up to a height of 15,000ft at Mach 0.45). Turbomeca Baitan. Single-shaft turboprop. Single transonic axial compressor stage followed by single centrifugal stage, annular combustion chamber and multi-stage turbine. Overall diameter, 21.6in; length as depicted, 60.9in; dry weight, with propeller but without oil-cooler, 585 Ib, or 397 Ib without propeller; mass flow and pressure ratio, not available; max rating, 650 s.h.p. at 33,000 r.p.m. (1,790 propeller r.p.m.) with s.f.c. of 0.73, available up to 14,800ft at Mach 0.4. is doubtful if it incorporates any components of the earlier Atars, and from a variety of sources it is possible to assess it as a very advanced unit indeed. Bearing in mind its announced applications in the Mach range above M 3, it is hardly surprising to find that SNECMA have lowered the pressure ratio, introduced variable-incidence blading in the inlet guide vanes and first two rows of stators, and switched to steel as the ruling structural material. Notwithstanding the latter fact, how- ever, the weight has been held at a value not much in excess of the latest Atars of half the thrust. Most of the data which may be quoted are given with the drawing; it is not surpising to find that, like Orenda Engines with the Iroquois, the fuel and control systems are housed in a cooled box, and special measures Ere being taken to prevent bearing tempera- tures from becoming excessive. It is known that portions of the Super Atar have been undergoing rig-testing at Melun- Villaroche, but no information is forthcoming upon the progress of the complete engine. The mere existence of the Super Atar as a firm pro- ject in itself is a matter of very great interest. It remains to be seen whether its development will be allowed to continue, or whether—like its counterparts in all other Western nations except the U.S.A.—it will fail to find a production application. TURBOMECA Societe Anoiwme Turbomeca, Bordes (Basses-Pyrenees). The list of small gas turbines produced by this private company located in the Pyrenees foot- hills has now reached alarming proportions; fourteen of the most common recent types were described in some detail in our last engine review issue and a smaller number are dealt with here. By far the most important engine has always been the Marbore turbojet, which has been in bulk production at Bordes for four years and is being manufactured under licence in several countries, as noted below. All the first families of Turbomeca engines employ simple single-sided centrifugal compressors, but in 1955 a new family of more efficient units was produced in which the pressure ratio was increased by the addition of a high-speed axial stage upstream of the centrifugal im- peller. The most important of this new family are probably the Turmo III turboshaft engine for helicopters and the Bastan fixed-wing turboprop. Artouste Some 300 of these single-shaft engines have been delivered, chiefly to power the Sud Alouette II helicopter. The standard Alouette engine is rated at 360 h.p. at 5,780 output r.p.m. (33,000 turbine r.p.m.) with a con- sumption of 335 lb/hr. The Artouste IIB1 was awarded a C.A.A. type certificate in January last year and, uprated by Continental to 425 h.p. are being supplied via the American company to power the Republic-assembled Alouette helicopters. Turbomeca are continu- ing development of the uprated Artouste III, which has a maximum power of 550 h.p. and (further uprated to 600 h.p.) can be provided with a drive for coaxial propellers. Astazou First revealed at the 1957 Paris Salon, this very neat single-shaft turboprop has completed a considerable amount of bench running, including pre-flight rating tests. It has a number of projected applications, and is being installed in a Broussard. Bastan Probably the most important of the company's current range of new engines, the Bastan has completed well over 1,000 bench hours and has started flying as the powerplant of the Beech Super 18 test bed purchased by Turbomeca Gabizo. Single-shaft turbojet with afterburner. Single transonic axial compressor stage fol- lowed by single centrifugal stage, annular combustion chamber, single-stage turbine, and afterburner with two-position nozzle. Overall diameter (on reheat pipe), 26.77in; intake diamerer, 17.7in; overall length as shown, 142.2in; dry weight, about 740 Ib; mass flow, about 45 Ib/sec; pressure ratio, about 5:1; max thrust, 3,396 Ib at 17,500 r.p.m. with s.f.c. of 2.25. Basic engine weighs 585 Ib, has rating of 2,420 Ib with s.f.c. of 105. oil oil Ir o G • :J= a 1 ii 'in11 "ff
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