Interesting subject. What I had proposed to do was to bring hot air, instead of ambient temperature air inside the carb intake. There seems to be another solution which is to heat the carburetor body itself. Now, I wonder... My intake is already from inside the engine compartment, which is probably very hot already. Should I bother, after all?
Serge Vidal KR2 ZS-WEC - Taildragger, VW powered (2.4 liter, dual electronic ignition) - Total aircraft time: 390h - Aircraft hangared at: Orleans, France - Pilot moaning in: Tunis, Tunisia E-mail: [email protected] <mailto:[email protected]> Most systems seem to heat the carb body. -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of [email protected] Sent: Wednesday, March 10, 2004 16:23 To: [email protected] Subject: KR>CARB & MANIFOLD ICING WITH VW ENGINES For gasoline, the change of state from an atomized liquid to a vapor is endothermic -- it absorbs heat. The resulting temperature of the fuel/air flow will depend upon the amount of heat available in the endothermic zone. Under the right conditions it is possible for the temperature of the endothermic zone to be below the freezing point even with ambient air temps as high as 90 degrees F. Worse-case, you may need more heat than you've got. In many cases the waste heat from a single cylinder of a 2180cc engine, 8.5:1 cr, engine isn't enough to keep the endothermic zone above the freezing point. Just as there are hypereutectic thermal barrier coatings that can keep the heat inside your exhaust pipes, there are thermal disbursant coatings which enhance the heat flow out of a pipe (or cylinder head). Used in combination you can effectively focus your waste heat inside the heat exchanger for your carb or cabin heat. (I'm using Tech Line's thermal barrier coatings. I've no experience with any of the others.) I've found stainless steel pot-scrubbers to be the best labrynth media for the heat exchanger (as opposed to door springs, etc). I've also found that spot-welded body-panel studs make the best radiating elements, assuming the entire assembly (ie, pipe & studs) is coated with a thermal disbursant (which also prevents rust). Finally, based on a 2180cc engine running 7.5:1, to provide sufficient heat for the worse-case scenario (ie, low temp, high humidity), I needed approximately 95 square inches of exhaust pipe surface, fed by two cylinders, to ensure an ice-free endothermic zone (ie, 90*F over ambient). YMMV. -R.S.Hoover _______________________________________ to UNsubscribe from KRnet, send a message to [email protected] please see other KRnet info at http://www.krnet.org/info.html
