Svein, Have flown with several groups of all sorts of Europas through rain
over the years, and have not known anyone to have any problems with the
engine system. Have heard but not experienced of propeller problems, and
would usually deliberately reduce prop RPM if rain cannot be avoided.
Regards, David Joyce, G-XSDJ
----- Original Message -----
From: "Sidsel & Svein Johnsen" <sidsel.svein@oslo.online.no>
Sent: Tuesday, June 08, 2010 5:13 PM
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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