The Mammoth Book of Space Exploration and Disasters

In the United States, initial research into the question of rocket propulsion was carried out by the Aerojet Engineering Corporation, founded in 1942. Within two years they had developed a solid-fuel Jato (jet assisted take-off) rocket. This consisted of a single cylindrical chamber inside which the solid propellant and oxidizer were moulded into a cartridge. The cartridge was fired electrically, producing a thrust of 1,000 lb for 14 seconds. Used on the Lockheed F.80, two Jato rocket units reduced take-off from 3,000 ft to 1,200 ft.

The first American rocket engine designed for straightforward aircraft propulsion was that developed by Reaction Motors. This was the unit used in the world’s first supersonic aircraft, the Bell X-1. It consisted of four cylindrical combustion chambers, each with a separate igniter so that they could be used individually or together. The chambers, expansion nozzles, and fuel system were supported within a frame of chrome-molybdenum steel, the whole unit weighing 210 lb. The fuel, a mixture of ethyl-alcohol and water, was circulated through cooling ducts in the exhaust nozzles and round the combustion chambers. Both the fuel and liquid oxygen were injected separately under pressure into the front of the combustion chamber, where the chemical reaction produced a jet velocity of 6,182 ft per second and a thrust of 1,500 lb from each chamber, or a total maximum thrust of 6,000 lb.

America’s first aircraft designed on the rocket-cum-turbo-jet principle was the Republic XF.9 in which provision was made for the installation of four rocket units in farings above and below the exhaust, to give extra power at take-off and for climbing. The XF.91 was powered by a General Electric J.47 turbo-jet engine equipped with reheat.

The Douglas D-588-II Skyrocket which reached Mach 1.03 in straight and level flight at 26,000 ft in July 1949, and attained Mach 2.0 at 72,000 ft (about 1,324 m.p.h.) on 11 June 1951, was originally designed to use both rocket and turbo-jet. Built to fly at 1,820 m.p.h. at 75,000 ft, it was at first equipped with a Westinghouse J.34 turbo-jet engine supplied with 250 gallons of ordinary aviation petrol giving a 30minute endurance, and the Reaction Motors rocket unit.

This was the same as that used in the Bell X-1 but it had only one-third the amount of propellant (3,000 lb) so that the total rocket endurance by using the chambers individually was about 3 minutes. At maximum power, the endurance was less than one minute so to save fuel, Jato rocket units were also used for take-off.

Later, the turbo-jet engine was abandoned because it failed to give the performance anticipated, and the space saved was devoted to increasing the supply of propellant for a new Reaction Motors L.R.8-R.M.6 rocket engine which incorporated certain small modifications on the 6,000 lb C.4 which was used in the Bell X-I. To enable sufficient altitude to be reached for the high-speed run, a B.29 Superfortress was used as a mother aircraft to carry the Skyrocket, fitted to the bomb-bays, to 35,000 ft.

A considerable quantity of fuel was lost by evaporation before the Skyrocket was launched, and in future the mother aircraft will no doubt carry rocket fuel so that it can top up the tank. As it was, by the time the pilot, William Bridgeman, had reached his altitude only 5% of the fuel supply was left. This gave him an endurance of about 3 minutes powered flight for his record breaking run during which he maintained a speed of over 1,000 m.p.h. for about 10 seconds.

Breaking the sound barrier

Chuck Yeager was a US Army Air Corps test pilot. Yeager:

The joke was on me.

It was just after sunup on the morning of Oct. 14, 1947, and as I walked into the hanger at Muroc Army Air Base in the California high desert, the XS-1 team presented me with a big raw carrot, a pair of glasses and a length of rope. The gifts were a whimsical allusion to a disagreement I’d had the previous evening with a horse. The horse won. I broke two ribs. And now, as iridescent fingers of sunlight gripped the eastern mountain rims, we made ready to take a stab at cracking the sound barrier – up until that point aviation’s biggest hurdle.

The Bell XS-1 No. 1 streaked past the speed of sound that morning without too much fanfare – broken ribs notwithstanding. And when the Mach indicator stuttered off the scale barely 5 minutes after the drop from our mother B-29, America entered the second great age of aviation development. We’d fly higher and faster in the XS-1 No. 1 in later months and years. Its sister ships would acquit themselves ably as the newly formed U.S. Air Force continued to “investigate the effects of higher Mach numbers.” And Edwards Air Force Base, formerly known as Muroc Army Air Base, would witness remarkable strides in supersonic and even transatmospheric flight.