europa-list
[Top] [All Lists]

Re: do it yourself strobes . . .

Subject: Re: do it yourself strobes . . .
From: Robert L. Nuckolls III <nuckolls@aeroelectric.com>
Date: Sat, 8 Aug 1998 17:49:30

>There was an article in kitplanes a few months back about how to build
>your own strobes with stuff you can buy at radio shack. It was the issue
>with the Lancair on the cover, I can get the date if anyone is
>interested. The article raved about how easy they were to see.

  I've seen many articles over the years on do-it-yourself strobes.
  Please understand that the maximum light output that can be
  expected from any strobe, amateur built or otherwise is a function
  of the energy storage capacitor and the voltage to which it is
  charged between flashes. The formula is:

  Energy (joules) = Voltage Squared * Capacitance (farads)/2

  If you have a 100 microFarad capacitor charged to 300 volts
  the potential energy is 4.5 joules.  Note that I use the
  work "potential" . . . the REAL light output is a further
  function of flash tube efficiency and series resistances
  in the flash tube current path that throw away some of the
  energy stored as heat instead of light.

  Most of the "do-it-yourself" articles I've seen are really
  puny in the stored energy and light output department.

  Another issue arrises with the strobe tubes recommended in the 
  articles:

  They're generally designed for photoflash applications . . . this
  might be 4 to 40 joule flashes . . . perhaps a few thousand
  flashes for the lifetime of the camera. Now bang this critter at
  a full 10+ joules (the smallest of commercial strobes found on
  most aircraft) at 1 flash per second and you get 3,600 flashes
  per flight hour. Tests I've run on many off-the-shelf photoflash
  tubes show the device is down to 50% of original light output
  in 5-20 hours.

  If you'd like to match current certified aircraft strobe 
  requirements, it's tougher yet.

  I'm thinking about doing an article on building your own
  power supply for off the shelf aircraft tubes and fixtures.
  You'd save perhaps 25% on the overall cost of the system
  and spend quite a few hours doing it.  I've watched the
  strobe light market for years with an eye toward competing
  and I can tell you, it's NOT an attractive market. That's
  why you'll probably never see a strobe system offered from
  the 'Connection.  At current prices from 'certified' suppliers,
  I can't justify it. I know they SEEM expensive but try
  to duplicate the performance for less money with a new
  design and the catalog prices get pretty attractive.


       Bob . . .
                       ////
                      (o o)
       <   If you continue to do       >
       <   What you've always done     >
       <   You will continue to be     >
       <   What you've always been.    >


<Prev in Thread] Current Thread [Next in Thread>