Recently, the folks at RDD finished installing a Therm-X de-icing system on N241DB, making it the first de-iced Legacy.

The system includes an airframe de-ice system, a prop de-ice system and windscreen de-ice.  The Therm-X system relies on a large alternator (100 amps at 70 volts), controlled by a solid state controller to heat tapes on the leading edges of the wing and h. stab.  These are cycled automatically when temperatures drop into the icing range.  Prop de-ice is done by heated boots, windscreen de-ice uses a pump to spray de-ice fluid.  For more info go to: http://www.rddent.com/products.html

I had the opportunity to inadvertently test the system today on a trip from Chattanooga to Tri-Cities TN.  There was no ice forecast, but on our approach to Tri-Cities we had to come down through a thin cloud layer.  Above the clouds we were in the bright sunlight well above freezing, but coming through the clouds the temperature dropped below freezing and we started to accumulate some rime ice.  We watched as the system “zapped” the ice off the wing – very impressive.

There are a couple of “costs” to the system in addition to the price (contact RDD for pricing).  The system weighs about 40 lbs and because of the position of the alternator (belt driven off the L front of the engine) the ram air needs to be reversed.  The system also caused a loss of about 6 knots; 3 from the airframe and 3 from the prop.  On the plus side the heaters protect the wing and h. stab against chipping and rain erosion.

The system is not approved for known ice, but does allow more time to escape from inadvertent encounters with icing (of which I have had a number).  I think it adds substantially to the cross country capability of the Legacy.

D. Brunner N241DB