Closing off the gills is likely to result in thermal stress and shorter
life of the alternator regulator, if you have it mounted in that region.
A permanent hot air vent (following shutdown) in the top of the cowl can
be achieved by leaving out the baffle seals around the top of the carb
airbox. However, I have yet to discover whether this also results in
flow reversal through the cowl-top NACA duct at high AoA.
I've recently opened up this duct (without the baffle seals and having
previously run on under-cowl air) and find that the significant power
increase (a good10+% I reckon and an additional 200fpm on climb out) is
a bit fickle, depending on flight condition, suggesting variable
effectiveness of the duct.
Duncan McF.
----- Original Message -----
From: R.C.Harrison
To: europa-list@matronics.com
Sent: Thursday, November 16, 2006 8:03 AM
Subject: RE: Europa-List: Oil cooler thermostat
Hi! Paul/ Duncan.
Thanks for the message below. Even without any gills but with the
Jabiru arrangement I had no such thing as cable tie meltdown. The
nearest sign I had was some "spirowrap" which ran under the exhaust
manifolds. As I said I believe the presence of the gills in flight
allows the upper cowl pressure to reduce so discouraging the downward
cooling flow. If the gills were added to allow residual cooling after
shutdown it would be simpler to open the top access panels immediately
on shut down. I have ordered "the fibre glass engine cooling hood" on my
engine which should also assist in preventing the heat build up in the
cowl top and I expect my intercooler air to assist with cowl top cooling
too. I would have expected the Jabiru being fully air cooled to have far
more residual heat to dissipate on shutdown anyway and since I didn't
have a problem then I will leave the gills on my new cowls closed,
unless I get some more feedback against.
I've not had a rattling response on the question
Regards
Bob Harrison G-PTAG
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Paul
McAllister
Sent: 16 November 2006 00:48
To: europa-list@matronics.com
Subject: Re: Europa-List: Oil cooler thermostat
Hi All,
Actually I have my gills rear ward facing. It wasn't by design, I
just made a mistake and I didn't even know until Andy pointed it out to
me.
Although I don't have before and after measurements, the underneath
of my cowl seems cooler that some other people have reported. I base
this on the fact that I don't have any cable ties that melt under the
cowl, whereas I have heard many reports from others.
One of these days I must smear a bit of oil around to see what is
happening
Paul
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]On Behalf Of Duncan & Ami
McFadyean
IConversion of the gills to a rear-facing exit may prove beneficial
(to reducing cooling drag), although care needed to ensure fuselage
composite not overheated. I have the moulds for such a mod., but never
tried it out.
Duncan McF
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