[ARC5] Testing battleship radios

[Michael A. Bittner]

FWIW, the first black box I designed as a young engineer at Douglas Aircraft (back when there was a Douglas Aircraft) was a specially shaped box to house eight relays used in the firing sequence of the Shrike missile on the Douglas A4 attack aircraft.  It had to fit between the inner and outer skins of the port jet intake duct as that was only place left to locate the box on that small jet.  The prototype was tested on a shake table that was set up to simulate the severe acoustic vibrations in that location.  When the box was opened at the end of the test, every single wire had broken off at its soldered connections and was laying in the bottom of the box.  The cure was to pot the end of each relay and the bulkhead connector were the solder lugs were with a rubbery potting compound.  Live and learn.  Mike, W6MAB
  ----- Original Message ----- 
  From: Geoff 
  To: jfor at quikus.com ; kgordon2006 at frontier.com 
  Cc: arc5 at mailman.qth.net 
  Sent: Saturday, November 03, 2012 10:40 AM
  Subject: Re: [ARC5] Testing battleship radios


  Smaller equipment such as radios was subjected to the shake table test, 
  during WW2 days it was likely driven by a pair of 833A's or bigger.

  In later years 4-1000A, 4CX5000A and others were used. National and Sanders 
  Associates used them regularly for defense contract testing and the ones at 
  Sanders would shake the old wooden mill building.

  Imagine the construction needed for the AN/WRR-2 and 2A to survive!





  ----- Original Message ----- 
  From: "J. Forster" <jfor at quikus.com>
  To: <kgordon2006 at frontier.com>
  Cc: <arc5 at mailman.qth.net>
  Sent: Saturday, November 03, 2012 12:48 PM
  Subject: Re: [ARC5] Testing battleship radios


  > There are standard shock tests pretty much like that. They are done on a
  > stand, composed of a platform on vertical steel rode with linear bearings,
  > like Thomson Ball Bushings.
  >
  > The gear is bolted to the platform, the platform raised a few feet and
  > held by a magnet or fast-acting latch. The gear is often instrumented with
  > piezoelectric accelerometers.
  >
  > The test is done by starting the recorders and relesing the platform. When
  > the platform hits a somewhat compliant pad underneath the platform, the
  > gear is subjected to a known, repeatable shock pulse.
  >
  > It is very scary to see one of your instruments subject to this treatment,
  > but it is required for aero-space hardware.
  >
  > Best,
  >
  > -John
  >
  > ==================
  >
  >
  >
  >
  >
  >> On 3 Nov 2012 at 8:28, Robert  Eleazer wrote:
  >>
  >>> One of my high school teachers, an early 1930's graduate of the Naval
  >>> Academy, described testing radios intended for use on WWII Navy ships.
  >>>
  >>> They tested the radio to ensure it was up to spec, then hung it from a
  >>> long rope, pulled it back, and let it slam into a steel wall.  Then
  >>> they took it down and tested it again.  It not only still had to work;
  >>> if it had shifted frequency by more than 1 KC it failed.
  >>
  >> Well, I dunno about that particular test, but I DO know that Grumman 
  >> would
  >> drop-test their airplanes to test the strength of their landing gear.
  >>
  >> The Hellcat was finally hauled to the top of the factory ceiling, about 
  >> 30
  >> feet
  >> as I recall it, and dropped. No damage occurred.
  >>
  >> I don't know if it had all its radio gear installed at the time.
  >>
  >> Ken W7EKB
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