Thanks for the interest, Chris. It was a long time ago, and my
involvement was with the aerodynamics and plate stresses, not the
details of the control system. I may still have a copy of the report,
but, because of the way things were packed into the space available,
there were few really good photographs. I will try to describe the
system in words, not my best medium.
The wind tunnel test section was 16 x 16 ft in cross section, and 40 ft
in length. Each nozzle sidewall was (from memory) about 54 feet long and
16 feet high, made up of two half-plates, each 8 feet wide. The walls
were supported by cantilevered electrically-powered ball-bearing screw
jacks, installed in upper and lower pairs, spaced 4 feet apart in the
low stressed region, and 3 feet apart in the higher stressed area. Each
jack station was connected from top to bottom with a drive tube, powered
by a single electric motor. Jack extension was measured by two selsyn
systems, one showing on the manual console, and a second set supplied by
the control system contractor. Curvature was monitored at the bottom of
each jack station by 2-level stress switches, which would give an alarm,
and eventually shut down power to the jack.
Jack position was specified in terms of extension toward the centerline
from the Mach 1 contour, which served as the baseline. When the drum was
rotated to the second row of pegs, a transfer plate was pulled down on
the pegs, where the position of the "L " extension on the peg moved a
cam surface, rotating a servo device that supplied that change in
position to an amplifier that specified the time and direction in which
the jack station was to be moved. Jack travel varied from around 30 in.
at the throat to an inch or so near each end.
By moving all jacks simultaneously, starting together, and stopping as
each reached the next contour setting, we were able to minimize the
transient stresses. ( I had to calculate the stresses at each of about
50 contour steps, to prove this was a safe approach to moving the
plates.) Aerodynamic shapes were provided in 0.10 Mach increments, with
guiding contours in between to limit the stress level of each change.
All jacks had to be checked and found to be "on contour" before the next
step was initiated.
It was quite an assignment for a guy whose only previous experience was
as a USAF Lieut. serving as a project engineer in a wind tunnel at W-PAFB.
Thanks for allowing me to go back in time. Probably a lot more than you
really wanted to know.
Jim Nichols
Tullahoma, TN USA
On 12/12/2013 5:54 PM, Chris Barker wrote:
> I'd love to see the way each position was transferred from the drum to the
> plates, Jim.
>
> thanks
>
> Chris
> On 12 Dec 13, at 22:19, Jim Nichols <jhnichols@xxxxxxxxxxxxx> wrote:
>
>> 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. :-)
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|
