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Aviation History
1963
1963 - 1427.PDF
FLIGHT International, 15 August 1963 actuator package by Air-Equipement, mounted in the centre of the aft closure. It has electrical input signalling and hydraulic actuation at a nominal 2,8451b/sq in. The package comprises: an electrically driven pump, with automatic regulation and water cooling; two hydraulic accumulators; an "autopressurized" reservoir; and filters and reducing valves. The output is by four hydraulic motors driving pivoted ball screwjacks. The linkage on the opposite side of the nozzle is a position pick-off to close the servo loop. Topazes have been fired in static test stands for well over a year, © lliffe Transport Publications Ltd 1963 with nozzles pointing upward and coupled to their actuating sys tem. SEREB told the writer that "from 1962 onwards" flight tests had been undertaken at Hammaguir, and that the recovered equipment compartment and ogive exhibited at the Paris Aero space Salon in June were not the only specimens brought back by this vehicle. All Topazes so far built are of the R&D configuration, with slender ogive. In all cases the ogive and equipment bay are recovered separately by parachute; those displayed at Le Bourget were from vehicle VE.lll No 3. By far the largest item in the equipment compartment (see data for the weight) was a SAGEM three-axis inertial platform and digital computer, which fairly obviously could apply to a military weapon as well as to the eventual Diamant. The VE.lll No 3 ogive was packed with flight instruments, recorders and telemetry. Having already discussed the two upper stages of Diamant, there only remains the first stage, which on its own bears the name Emeraude. This is the only liquid-propellant part of Diamant at present, and it has been evolved by LRBA during the past five years as a logical extension of the Veronique programme. The bare motor is named Vexin by LRBA, and it is the largest of a 245 series of engines of generally similar techniques but different sizes. Like the later Veroniques the propellants of the Vexin engine are white fuming nitric acid and turpentine. Material of the pro- pellant tanks is high-strength steel, rolled and welded by Nord- Aviation, who also make the skirt and fins. The acid tank is above that for the fuel, and in its upper part, bolted to the inside of the upper closure bulkhead, is a gas generator which pressurizes both tanks to ensure propellant feed under all flight conditions. The French have yet to fly a large rocket vehicle with turbopump feed, although SEPR have plenty of experience with pumps in aircraft rocket engines. SNECMA were entrusted with the Vexin gas generator. It is of surprising dimensions, and contains an ignition system, charge of solid fuel, filters and coolant for the hot gas, and delivery to both tanks and to a turboalternator supplying 400c/s power for instru mentation and electronics. The gas generator is of welded steel construction. SNECMA also manufacture the thrust chamber, apart from the bolted-on injector face. Both Flo-turning and centrifugal casting are established SNECMA techniques, both of which are certain to be important in the joint work with Nord in the development of future ballistic stages with metal cases which was recently an nounced. The Vexin chamber has film cooling by the nitric acid, and the welded nozzle is designed to a relatively low expansion ratio. In the centre of the injector head is a differential gimbal joint with two perpendicular bearing shafts. The chamber is gimballed about these axes by Jaeger pitch and yaw actuators with irreversible screwjack output. Matra and Bronzavia are two of the principal accessory companies on the Vexin, contributing most of the valves and piping. The two main feed lines to the chamber accept varia tion in length and angle as the chamber gimbals. Vehicle control is accomplished in pitch and yaw by motor gimballing. In roll the Emeraude is stabilized by trailing edge aerodynamic controls on an opposite pair of the fins. These controls are actuated by surface power units mounted adjacent to the surface axis on the inside of the skirt. The electronic units of the autopilot are mounted at the top of the stage, with four service fairings down the outside. Static firings of the Vexin motor began at Vernon several months ago—SEREB will not say exactly when—and a number of firings have taken place both in protected revetments and on the big new test stand, which can accept complete vehicles larger than Emeraude, which was formally commissioned in March. In R & D form Emeraude will normally fly with a dummy second stage ballasted to Topaze weight, plus a similar Sud- Aviation equipment bay and telemetry head. Equipment would be the same as that listed for Agate, without the flasher unit but with the addition of magnetic and duplicated SFIM recorders. The vehicle is launched from a platform rotatable in azimuth and has an R & D ceiling of 200km. Emeraude is available for space research at the end of 1964 against orders placed 15 months earlier. Mated to the Topaze second stage the big liquid first stage produces the two-stage Saphir. This has excellent performance as a space booster, and is almost identical to Emeraude apart from having a live second stage. Availability of Saphir is listed as mid- 1965 for vehicles ordered 24 months earlier (i.e., now). All that is needed to produce Diamant is to add the live third stage. All three of the big jewels look superficially similar, and dimensions and weights are comparable (see data). One major difference is that the single-stage Emeraude and two-stage Saphir are stressed for heavy payloads, whereas Diamant is designed specifically for placing relatively very small payloads in orbit. Nominal satellite weight assumed for Diamant is 80kg (1761b). Basic orbit, on a firing toward the East at 30°S latitude (Colomb- Bechar), is taken to have perigee of 400km (249 miles), this being the minimum necessary to ensure 300km perigee on 95 per cent of launches. With an 80kg payload the corresponding apogee is 1,300km (808 miles), giving an orbital period of lhr 42 min. Performance in circular orbit is plotted on an accompanying dia gram (page 243). Vehicle launch and control are as previously described for the three stages. A typical trajectory was sketched in our issue for June 28, 1962. Points worth noting are: vehicle attitude is programmed to hold incidence close to zero throughout the first- and second-stage burn; these two stages are separated by actuators fed with gas from solid fuel (possibly the main gas generator will be used for this supply), following which the second stage is ignited and the two
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