From: N295VV@aol.com
Message-ID: <889c86e.35f523b9@aol.com>
Date: Tue, 8 Sep 1998 08:31:53 EDT
To: lancair.list@olsusa.com
Subject: Re: heater, IV
Mime-Version: 1.0

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From:  n295vv@aol.com

well, the plot thickens.  you will recall  my comment last week-i was flying
to the homecoming, and the heater flapper valve was letting hot air into the
cockpit--lots of hot air?

i have an early IV.  there are two tubes welded on the back of the turbo
intercoolers.  they are there to bleed very hot compressed air from the
intercoolers and provide the hot air to heat the cockpit, hopefully during
cold weather.

this system has a flapper valve actuated by a push-pull cable to control flow.
i have noticed several things about it over a period of time:

1) at less than 31" it doesnt heat at all in the winter. (well, duh, the
engine is actually 
        sucking air, not producing a higher than ambient pressure which can be
bled to 
        the cabin--this has somehow escaped the attention of the folks at the
factory--
        no one at the factory could understand this--apparently they  never
have to use 
        the heater in oregon.

2) it leaks hot air like crazy at all times at 31" plus-summer or winter

3) the leakage with the valve closed drops MP and reduces top KIA by 10 Kts--i
dont    
        even want to guess what the drops are when it is fully open.

4) since at less than 31" it doesnt blow hot air, i assume it is sucking
unfiltered                      
         cockpit air into the turbos

After talking about this problem with the factory, i have gleaned the
following information--the leaking flapper valve can be solved by replacing it
with a new tubular assembly for $400.  well, leave the leaking valve inline,
and add this to it.   ok.

the minus 31" problem?  Engineer--"well, we have never heard of this, are you
sure that this is happening?"   "well, yes, i am--do you want to talk to my
wife?"   "well, you could just connect it to a heat muff like we are using on
the ES."  "fine, i want to buy a heat muff."  "we dont sell heat muffs"
"where can i buy a heat muff?"  "i dont know."   and on it went.  i finally
decided i am going to weld up my own damn heat muff and disconnect the
plumbing from the intercoolers.  i dont have the foggiest idea of what heat
system they are supplying with the current kits--maybe it is still the system
i have--i saw an engine there with the tubes coming off the intercoolers.  if
so, a lot of people are freezing their hind ends off in winter.

am i missing something here?  am i the only IV pilot with the turbo bleed
system?  do you other guys have exhaust crossover pipe heat muffs?  if so,
where did they come from?  most importantly--have my wife and i got
alzheimer's, and only imagine that the system produces no heat at less than
31"?  please, please email me if this is happening to you also--i will cancel
my doctor appointment if i find i am not the only one.

and, oh, by the way, the homecoming was wonderful.  lots of good food, good
people, great looking planes, and wonderful weather.

david jones
pecatonica, illinois   n295 v v @ aol.com