----- Original Message -----
From: "Perry Casson" <pcasson@sasktel.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, March 07, 2004 11:53 PM
Subject: [FlyRotary] Re: Cooling System Dynamics


> Hi All,
>
> I had a bit of excitment today that was cooling system related.  Flew
> this AM for about 1.4 hours (6.5 hours total) with no problems and was
> delighted to see I'd finally got the heavy left wing resolved.  This
> afternoon under a warm spring sun I took off, had just climbed to 4500'
> and found it was actually warm enough to turn the cab heat off for the
> first time this year.  About 10 seconds after turning off the flow of
> coolant to my heater core I could smell something and a slight white
> smoke came up from under panel.  Pulled the power back, radioed the
> tower I could smell something and headed back to the circuit.  Smell and
> smoke appear to have cleared  while decending and I made a normal
> landing with the emergency trucks there to greet me at the taxi way.
> When I got to the hangar I first started to look under the panel for
> something that was heat damaged but everything looked fine so I removed
> the cowl and really could not see much wrong there either untill I
> noticed a bit of moisture on the overflow line from the coolant
> expansion tank.
>
> So what I think happened is, turning off the flow to the heater core
> caused a pressure increase in cooling system which burped a bit of extra
> coolant into the expansion tank which was enough to cause it to overflow
> the tank which had a too short of hose on it so it dripped a bit of
> coolant on the header pipes which caused the smoke.  Before I fly again
> I'm going to switch over to the pressurized recovery tank and move the
> location over to the cool side of the engine as I prefer not seeing
> trucks with flashing lights waiting for me to land.
>
> Perry Casson
>

Glad to hear all turned-out well.  Its amazing what gets your attention in
the air that you might not even notice in a automobile {:>)

Ed Anderson


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