Further to the other good reasons of avoiding blockage and rain ingress
already put forward, the mod 38 leaflet also says that the mod is: "To
minimise pressure changes due to changes in engine power or airspeed it
is desirable to avoid any pitot pressure in these vents." The reason
this is undesirable is not included in the leaflet, but it is simply
because the volume of air between the sight gauge vent inlet and the
column of fuel in the tube is much smaller than the volume of air
between the tank vent inlet and the fuel surface. Hence any change in
pitot pressure applied to both the vents would take much longer to
change the pressure in the tank than in the sight gauge, resulting in
false sight gauge readings until equilibrium was reached.
Mike
Dr Mike Gregory
Europa Club Safety Officer
-----Original Message-----
From: owner-europa-list-server@matronics.com
<owner-europa-list-server@matronics.com> On Behalf Of D McFadyean
Sent: 24 June 2021 14:58
Subject: Re: Europa-List: Is Mod 38 a good idea?
--> < <mailto:ami-mcfadyean@talktalk.net> ami-mcfadyean@talktalk.net>
The Mod was introduced following the experiences of John Tye flying in
rain, when water entry to the fuel tank via the forward-facing vents was
suspected as the source of a rough running engine. It seems to work!
Duncan McF.
> On 24 June 2021 at 12:27 tonyvaccarella <
<mailto:tony@weimagine.com.au> tony@weimagine.com.au> wrote:
>
>
> --> < <mailto:tony@weimagine.com.au> tony@weimagine.com.au>
>
> I only just became aware of this Mod that drills 2 x
1/8=C3=A2=82=AC=C2=9D holes at the rear of the fuel vent. From what I
read, it=C3=A2=82=AC=84=A2s intent is to prevent too much pressure
being developed in the forward facing vent and therefore within the fuel
tank.
>
> Having some =C3=A2=82=AC=C5=93pitot=C3=A2=82=AC=C2=9D pressure,
I would have thought, would be desirable.
>
> Im interested to know who has incorporated this Mod and would you
recommend it? Europa lists it as desirable.
>
> Thanks
> Tony
> Sydney Aust
>
> --------
> Tony Vaccarella
> Mascot NSW 2020
> Sydney Australia
>
>
>
>
> Read this topic online here:
>
> <http://forums.matronics.com/viewtopic.php?p=502573#502573>
http://forums.matronics.com/viewtopic.php?p=502573#502573
>
>
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