While my scheme is not literally using air from outside of the cowling, the
duct created by CD1, CD2, CD3, and the rubber seals against the fiberglass
cowling isolates the cooling air flow from everything else within the
cowling. More importantly, and not apparent unless you see the actual
design, there is a stainless steel "fire door" that will shut off the air
flow to the cockpit (at the firewall) if there is a fire within the
cowling - the "fire door" closes automatically because it is spring loaded
and held open by a fusible link that will melt at 100 deg C.
Unfortunately I can't overcome the objection to a burst heat exchanger
allowing hot liquid into the cabin air stream. However, the way that I have
designed the intake to the SCAT tube would minimize ingestion of liquids
into the cabin air, and unless the occupants were incapacitated it would be
easy enough to shut off the flow of heated air.
I've attached the details of my scheme to another message posted with this
one.
Best regards,
Rob Housman
A070
Airframe complete
Irvine, CA
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]On Behalf Of Richard Holder
Sent: Friday, September 15, 2006 10:44 AM
Subject: Europa-List: Heat exchanger for the XS Europa
Rob Housman wrote:
> Perhaps I misunderstand what is being offered, but the
> word "exhaust" suggests to me that this device would be
> a heater muff added to the Rotax exhaust plumbing. If
> so, why add the weight and risk of a carbon monoxide
> sucking muff when there is already ample warm (hot?)
> air available aft of the water and oil coolers?
> What the Europa factory forgot was the necessary
> ducting to get warmed air into the cockpit. Anyone
> interested can contact me off list for the details of
> how I ducted warm air from aft of the two coolers,
> unheated air from the 914 turbo air inlet, and mixed
> (or not, as desired) the two prior to being ducted into
> the cockpit.
Here in the UK any cabin air must be sourced from outside
the cowling. Without any chance of under-cowling air
getting in there.
The rationale is that if there is an engine fire then any
under-cowling air pick-up will pick up smoke and flames
and these are undesirable inside the cockpit.
Any heater/demist using an exhaust muff must have the muff
fed from outside the cowling and then led through the
firewall. And then the CAA/PFA will want some type of
integrity test or a solid blanking off plate on the
firewall also.
The "warm air aft of the water & oil coolers" route would
also have a problem if either radiator split and hot oil
or water was streamed up your duct into the cockpit.
A long shot but that's the way the CAA looks at things and
it costs us dear :-(
In the Land of the Free you are free to risk whatever you
like as YOU have to sit in it. The CAA would like anyone
who sits in the plane to be guaranteed safety :-) Ha ha !
Just my two-penny worth.
Richard
G-OWWW
High Cross
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