How to make a KiteLab Ducted Turbine APU (RAT)
Groundgen systems need Auxiliary Power Units (APU) to power signal lights,
at a minimum, and potentially to power actuation, sensing, and other
applications at altitude. These power requirements are a small fraction of
rated power, and wind is the obvious source of aux power, so a small wind
driven APU make great sense. A traditional aviation method is the Ram Air
Turbine (RAT). Especially with kites, a housed aux turbine is the most
practical solution to avoid mishaps.
To make a KiteLab style RAT find a suitable DC fan first, like a computer
muffin fan or personal battery operated fan. The best such fans for this
use have unswept symmetrical foils whose camber can be oriented for good
Next wade through a plastic recycling cache and fit the lightest possible
duct as closely as practical to the fan. You may even find a fancy venturi
shape. Mount the fan securely in the tube. Make provision for the RAT to
be securely mounted in an AWECS or hung in stable flight (with fins)
(commonly as a Nav Marker).
Connect contacts to a suitable voltage regulator, upconverter, etc.. The
simplest circuit is a diode/capacitor combo connected to a battery or
Photos of such AWE APUs are part of a pending KiteLab mass-disclosure
soon. Expect RATs to find a large market as AWE APUs.
Sept. 21, 2011
Comment and development of this topic will be occurring here.
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