Dear All,
I have a tri gear Europa Classic with a XS firewall forward setup and a
912ULS with a NACA on top of the cowling for the carbs. I have flown through
very heavy rain, light rain etc (I am based in the UK) with no problems.
My rads oil & water are one behind the other with quite a gap at the bottom
which lets air bypass the rads. The temps are fine and I have been as far
south as Morocco with it in the summer and very hot conditions.
I don't often say anything on this forum as
1. I don't understand the technical stuff.
2. I am too busy flying it.
Kevin
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Sidsel & Svein
Johnsen
Sent: 08 June 2010 17:13
Subject: Europa-List: 912S - Flying in rain
The current thread on combustion air, ram pressure, where to place the air
intake, etc. brings up the issue of flying in rain with the Europa equipped
with the 912S, having the air intake arranged as a NACA duct on top of the
cowling and the plenum box just below the opening. There are two 3.3 mm
(1/8") drain holes at the bottom of this plenum box, which will be able to
drain away some water intake (you must fly with the ball in dead center for
both to be effective). A certain air pressure build-up in the plenum makes
the drainage more effective.
One theory I have heard goes as follows: If the engine were stopped and
surrounding air passed over the cowling at a speed of say 120 knots, very
little rain would enter the air box. The air would be backed up in the NACA
duct and "new" air and rain drops would for the most part pass over it.
Given this starting scenario (the aircraft moving at a speed of 120 knots):
If you now have a running engine it will still not suck in so much
combustion air that the velocity through the NACA duct is anywhere close to
120 knots + propeller slip stream velocity. Air would therefore still be
backed up in front of the plenum intake, with a certain amount of the air
and rain drops flowing over the inlet.
Theory and reality are two different matters also in this case. What has
been experienced when it comes to flying this configuration in rain
(drizzle, light, heavy) - is it definitely to be avoided or is it more a
matter of vertical and horizontal visibility?
Regards,
Svein
LN-SKJ
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