Sonex Cowling Installation Instructions - Manual

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Builder's Guide Cowling Installation
Getting Started
__ 1. Accurately build and install the Alignment Spacer
detailed on the Cowling Installation drawing of your
plans.
__2. Remove material from the front of cowl to clear the
prop hub. Leave about a 1/4" lip.
The opening for the prop hub must be cut to eliminate interfer-
ence between the cowl and the flange of the prop hub.
Rev N/C 07/13/08
__ 3. Rough cut the openings for the cylinder head cooling
air. This will provide a "handle" for handling the cowl
during the fitting process.
Fitting the Right Side
Fit the right cowl half first, ignoring the left side altogether.
__1. Rough cut a clearance
hole for the main gear
leg, or the nose gear
strut, until the cowl can
be positioned behind
the prop hub spacer
and against the side of
the forward fuselage
skin.
These supplementary instructions are not intended to detail
every aspect of the cowl installation. They are supplemental to
information contained in the plans and Sonex firewall forward
installation manuals provided when you purchase your engine
from Sonex Aircraft LLC. They illustrate the most common
questions builder's have when installing the cowl. Each builder
will likely develop their own fitting procedure and the correct
one is the one that works for you to achieve the installation
depicted in the plans.
Important Information About Your Cowl
The cowling is not provided as two matched halves. It is two
oversized halves which generally must be trimmed on all
edges to achieve a proper fit. Gaps in an untrimmed cowling
are not an indication of too little material (an undersize cowl),
rather it indicates too much material (an oversized cowl).
General Guidelines
Fitting the cowl takes time. Be prepared to install and remove
the cowl dozens of times during the fitting process.
Do not force the cowl into place or use ratchet straps. This will
only build stress into the cowl and make the installation more
difficult. If the cowl does not seem to go into place, look for
interference with the engine, landing gear legs, and prop hub.
Final fit and finish is up to each individual builder. The same
cowling is provided in each kit, and the difference between an
award winning installation and one that is "good enough for
who it's for" is up to each individual builder.
Proper fit of the cowl also depends on the care and accuracy
of the engine installation. If you are having problems fitting
your cowl it may be worthwhile to check the accuracy of your
engine installation.
The polyester cowl can be repaired / modified with any off-
the-shelf fiberglass repair kit.