Archived posting to the Leica Users Group, 2013/12/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]As a young engineer, my first assignment was to calculate the nozzle plate shapes for a flexible plate nozzle for the AEDC 16-Ft Transonic Wind Tunnel, then under construction. The shapes had to vary from a simple contraction to a Mach 1.6 contour, and the process had to be done by 16 pairs of jacks, without over stressing the steel plates. And, other than the basic supersonic shapes calculated by folks at Cal-Tech, it was all done on Friden and Marchant desk calculators. To move the jacks from contour to contour, a series of steps were chosen that stayed within stress limits, as determined from curvature calculations. These steps were then stored in L-shaped pegs on a mechanical memory drum, with the shapes transferred to cam-driven readers and fed to vacuum-tube amplifiers which supplied the driving signals to the ball-bearing screw jacks. Bear in mind that this was all done in the early 1950s. This photo, taken from my technical report, shows the mechanical memory drum and the console which contained the drum drive system, the transfer plate, and the individual jack amplifiers. The console and system were designed to our specs and provided by an engineering company whose name does not come to mind after 60 years. http://gallery.leica-users.org/v/OldNick/Mechanical+Memory+Drum.jpg.html Memory has come a long way since then. :-) -- Jim Nichols Tullahoma, TN USA