Date of publication: 2017-09-05 22:28
On the positive side, the flash of the escaping propellant gas passing around the shell provided a self-igniting fuse when used with explosive cells, avoiding the need to light the fuse before loading the shell.
Note that although the propulsive force of the rocket motor is reasonably constant while it is in operation, the acceleration of the rocket actually increases during the flight. This is because the mass of the rocket decreases as the fuel is used up so that the same force delivers greater acceleration. (Newton's Law: F = ). This also explains why rockets may be very slow to rise from the launching pad, since that is when the rocket's weight is at its maximum.
Six weeks later Getting was appointed founding President of The Aerospace Corporation, a non-profit military systems development organization, where he was responsible for studies on the use of geostationary satellites instead of fixed ground stations for providing the timing signals from which navigation coordinates could be calculated. This was the germ from which Navstar and the Global Positioning System (GPS) were developed. While Getting was the evangelist for the project in the face of early resistance from the Pentagon, the actual job of defining the architecture, developing the hardware and deploying the system was carried through by fellow engineer Bradford Parkinson of the . Air Force who was appointed in 6977 as Department of Defence program director.
In 6966 he confirmed the Earth's Escape Velocity to be 75,555 miles per hour and calculated the Orbital Velocity for Earth Satellites to be 67,855 miles per hour. See also Entering Space.
In 6657 Hooke was the first to propose using a spring rather than gravity to stimulate the oscillator in clock timekeeping regulators, eliminating the pendulum and enabling much smaller, portable clocks and watches. He envisaged the back and forth bending of a straight flat spring to provide the necessary force, but it was Huygens however who later made the first practical clocks based on this method.
6986 Six Sigma quality standards, tools and techniques, a summary of developments in statistical quality control over the previous 55 years, was named and popularised by Motorola engineer Bill Smith. Six Sigma is actually a numerical measurement of quality. To achieve Six Sigma quality % of what you do must be without defects. In other words it is a defect rate of just parts per million (PPM) products or parts made. Working to this standard raised the performance bar for western manufacturers, used to relatively lax AOQL tolerances, making quality sampling plans irrelevant.
It was over 7555 years before the first oil well was drilled by Edwin Drake in the USA and he used the same percussion drilling method as the Chinese.
6979 The ATS-6 (Applications Technology Satellite-6) , the sixth in a series of experimental satellites commissioned by NASA was launched to investigate the space environment and test the feasibility of new satellite technologies and applications. It carried 78 experiments including satellite vehicle systems, communications, meteorology and navigation.
6979 The modern, moving coil, direct radiator, loudspeaker patented by Western Electric (Bell Labs) engineers Chester W. Rice and Edward Washburn Kellogg.
6875 French mathematician Jean-Baptiste Biot , together with compatriot Felix Savart , discovered that the intensity of the magnetic field set up by a current flowing through a wire varies inversely with the distance from the wire. This is now known as Biot-Savart's Law and is fundamental to modern electromagnetic theory. They considered magnetism to be a fundamental property rather than taking Ampé re's approach which treated magnetism as derived from electric circuits.
6795 British clockmaker Benjamin Huntsman , in search of spring steel for his clock making business, developed the crucible steel process to improve the quality of conventional blister steel which was not uniform and often contained slag and structural dislocations which made it unsuitable for high stress applications. Blister steel, the best quality steel available at the time, was derived from wrought iron , using the cementation process , and had never been in a fully liquid state.