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Aviation History
1951
1951 - 1241.PDF
770 EVOLUTION OF THE GUID. fig. 18. The A-9/A-10 po powerful booster rocket be hd dl i) i t. T$y the addition oja the A-9 (which in thispf ( case had delta wings) it was planned to extend the range to 3,000 miles. TABLE 1: ALTERNATIVE SCHEMES FOR Item Gross weight (Ib) Individual it«p weifht (ib) Main propellant weifht (Ib) Structure weifht (Ib) Hydrofen peroxide and calcium permanganate (Ib) Payload weifht (Ib) Exhaust flow (Ib/sec) Thruit at tea level (Ib) Lenfth (ft) Maximum diameter (ft) Span over fins (ft) Specific impulse (sec) Firinf time (sec) ... Structural factor < — structure weifht structure weifht+fuel weifht Mass ratio Mo t Velocity at "all-burnt" (ft/sec)... Altitude, "all burnt" Ranfe (miles) ... GERMAN Schema 1 A-10 188.090 15X240 11.470 37.470 330 35,850 •2031 441,000 65.5 13.5 29.5 •198 •50 0.246 2.56 3,937 80.000ft — A-» 35.850 35.850 26,260 . 6.615 772 2,200 •276 56,000 46 5.4 •203 •95 0.197 4.07- 10.42 effective 3,200 100 miles 3,105 A-9/A-10 PROJECTS Scheme 2 A-10 220.460 191.800 136,700 55,100 Nitrofen pressure f__j•ceo 28,6602,728 441,000 11.5 166 50 0.288 163 3,937 80,000ft — At 28.660 28.66017,640 19.3101 8.8206.740+ 410 2,200 260 276t 55.130 60,000t 46 5.56 — 212 (218)f 68 (70)t 0.318 (0J56)t 2.7-7.1 effeetivef 3.2-8.4 9,200 100 miles3.105 •Figures extrapolated from existing data and in correlation with available informa- tion on these two schemes, t Alternative schemes for A-9. In the A-9/A-10 project, the extended range was to be achieved by providing the A-9 with a single 68-ton booster, intended to reach the "all-burnt" condition at an altitude of 8o,ooofr (Table I) and give the delta-rocket a starting velocity of 3,9ooft/sec (2,660 m.p.h.). After the booster had been jettisoned, the A-9, continuing the climb, would reach a final velocity of 9,2ooft/sec (6,260 m.p.h.) and, being then in highly rarefied atmosphere, would follow a ballistic curve. On the return to denser air, aerodynamic controls would terminate the dive at a height of 28 miles. The velocity would by then have risen to almost r i,7ooft/sec (7,970 m.p.h.) and with this large amount of kinetic energy to dissipate, the gliding range was estimated at 3,000 miles. As originally planned, the A-10 booster component was to use a nitrogen pressure system for feeding the propellants, but in a later conception turbo-pumps were substituted, which accounts for the alternative schemes specified in the table. Like the A-9 itself, the booster was stabilized by four gyro-controlled graphite vanes placed symmetrically around the exit of the venturi. The four large fins on the A-10 were heavily braced to support the vehicle on the ground, and four long guide-members embedded^, in a flat concrete base entered stout vertical tubes, one in each " In addition to taking the compressive load, these would hold th1 rocket steady in the initial moments of take-off. The nose section of the booster was slotted to receive the delta-rocket, which was backed onto a thrust ring. Fully fuelled, the complete vehicle would weigh over 80 tons. The A-10, incidentally, was supposed to be recoverable after use and incorporated air-brakes and parachutes of a special design which would open despite the rarefied condition of the atmosphere at the time they were brought into use. Each was to have double panels in its canopy, and the introduction of compressed between these panels formed a kind of semi-rigid parachute independent of the prevailing air density. Thus, whereas normal- type parachutes would have been torn to pieces by the violent build up of pressure, the "self-inflating" canopy could be opened FLIGHT, 29 June 1951 at an extreme altitude from which it gradually took effect upon the atmosphere, serving as a gentle brake for several miles until the condition of free fall was safely arrested. The A-9/A-10 was in an early project stage at the war's ending and although it was claimed that, given another [year, Peenemunde —the rocket research station on the Baltic coast, now in Russian hands—could have produced an experimental prototype, the scale of the undertaking was such that many years of preliminary research would have been necessary even with the equipment and skilled personnel available at the time. However, the masterpiece of engineering called "V.2" is sufficient testimony to the abilities of the German rocket scientists, and one would not like to hazard a guess as to whether large step-rockets of the type described do not, in fact, exist today behind the impenetrable screen of the Ural Mountains. The Americans, for their part—according to the recently published Stuart Report—do not expect to have such weapons before i960. Generally speaking, there are two methods to consider for the guidance of missiles over long ranges, the electronic system (variations of which have already been discussed) and the wholly automatic system. Of the two, the former is the more fully developed, but owing to its susceptibility to enemy counter measures, attention has returned to the automatic type of control, and attempts are being made to develop the inertial system, e.g., the technique used in the A-4 rocket. A likely method of improve- ment may be found in a telescopic device, pre-set to follow certain star patterns, whereby the inertial system may be monitored to maintain an accurate trajectory. It had been further suggested that, for test purposes, the A-9 might be provided with a pressure-cabin and pilot and at the end of its flight be landed on a conventional undercarriage. The land- ing speed with empty tanks was estimated at 100 m.p.h. In such a project, we might at least have learned something about human reactions over a wide range of gravity. Not only would the pilot experience zero gravitation conditions over the free path of the trajectory but, of course, a severe induced "g" during the flattening- out of the dive. And added to his discomfort at this period would be a rather warm cabin; skin friction would produce a maximum local stagnation temperature of 7,000 deg K ! A similar, though in some ways even more drastic, technique was suggested by Dr. Saenger in his supersonic-bomber project. Here, on diving back into denser atmosphere, the vehicle was literally to bounce on the upper layers of air and, in being thrown upward again, to describe a kind of wave-shaped trajectory, much the same as that a flat stone will follow if ricocheted across water. Each plunge into the denser air would result in part of the kinetic energy being consumed, so that the initially long jumps would gradually become shorter, finally to be transformed into an even gliding flight. These latter proposals are admittedly beyond the province of the present discussion, but they do show the nature of ideas that existed in Germany in 1945 on the question of long-range bombard- ment. It is known that copies of these design-studies fell into Soviet hands; and much of the German research equipment and hundreds of German technicians who had worked on missiles were moved to Russia. It would therefore be unwise to discount any one of these projects. Where development work is fed by huge sums and is given high priority in skilled manpower, and labour is so cheap that thousands of workers can be thrown in to build vast research establishments, test ranges and factories, the time normally reckoned (by our own standards) to produce these revolutionary weapons might easily be halved. In this country, hard-pressed though we may be economically, it is vital that research be directed toward combating such advanced weapons. It is said that no method of attack can exist for which there is no effective counter measure. That may be so, but in the case of the supersonic missile, the means of attack is at the present time far ahead of the means of defence. Fig. 19. :e was a multi-step rocket; it Is here seen on mobile launching ramp.
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