Rowland,
The restrictor orifice dimension you quote is the stock Europa size, i.e.
about twice what Rotax recommend, and what everyone else has!
Duncan McF
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Rowland Carson
Sent: 21 June 2013 18:20
Subject: Europa-List: fuel return line restrictor
--> <rowlandcarson@gmail.com>
While delving into the various Rotax manuals in pursuit of information about
the fuel manifold, I noted the dimensions of the restrictor in the fuel
return line - 0.35mm ID.
I have been considering the most elegant way to incorporate the restrictor
supplied by Europa (FS02) into my home-brewed alternative to the Rotax
manifold and so checked its dimensions. I find that the restrictor hole will
easily pass a number 71 drill bit, but barely accepts the shank of a number
70 drill bit. So I deduce that the orifice is about 0.7mm ID, ie twice the
diameter of the Rotax one.
Why should Europa have supplied a different size of restrictor from that
called out by Rotax?
Looks as though the Rotax orifice will (in any otherwise identical
circumstance) allow the fuel pressure to build up slightly higher, and
return less fuel to the tank, than the Europa one. It might just make the
difference between pass and fail in a fuel flow test.
Has anyone had any issues traceable to this difference between the
Europa-supplied restrictor and the Rotax one?
I might consider machining up my own manifold (obviously I'm heading into
deep water with LAA engineering here) and if so, which size of orifice
should I incorporate? Should it be removable, rather than integral, to allow
fine-tuning of fuel pressure?
in friendship
Rowland
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