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From:  n295vv@aol.com   (n295  v v @aol.com)

Re Mike Smith's questions on the heater for the IV--I am building a heater
control valve that will not port the hot air from the turbos overboard, and I
will let the people on this site know when it is finished.

Compressing hot air and then dumping it overboard when it wasn't neeeded was
not exactly a stellar idea on Neico's part.  Additionally, the new $500 rotary
valve replacement is a piece of junk--leaks hot air like crazy into the
cockpit--it is actually leakier than the old flapper valve it replaces.

Our new heater valve we are making will be radially honed, with fit tolerances
less than 0.001", making it well capable of shutting off hot air withour
dumping it overboard.  The Neico valve measured out 0.035" sloppy between the
concentric tubes.  Additionally, the new factory assembly had the cable attach
flange welded in the wrong spot, causing a severe cable binding problem.

In all fairness, I think it was designed for the ES, where the pressure was
probably less than one would find in the IV, since the ES probably was drawing
heat from a muff.  The rotary design itself was quite inventive--the execution
just sucks.

I will let you know when they are available.

David Jones,
Pecatonica, Illinois  (RFD)