Sonex AeroVee 2-into-1 Stainless Exhaust Installation User Manual

Page 2

AeroConversions, Inc.

Cowling Considerations

The 2-into-1 exhaust will work with any of the Sonex-pro-
vided cowls.
Cowl with Pre-molded (Fiberglass) Exhaust Tunnels.
If your cowling has the premolded exhaust tunnels, the tunnels
must be opened as described in the Sonex/AeroVee Installa-
tion Guide. These openings provide the necessary outlet for
the engine's cooling air.
You will also need to make a cowling cut-out at the ﬁrewall
large enough for the exhaust pipes to exit. The cutout should
be large enough to clear the exhaust, but not over-sized. If the
cut-out for the exhaust is too large it can degrade engine cool-
ing.
A small deﬂector lip must also be ﬁtted in front of the exhaust
pipe outlet, and a curved stainless steel deﬂector may be added
to the bottom of the fuselage skin for the exhaust to spill
against.

This photo shows the standard outlet for a 2-into-1 exhaust
ﬁtted to a cowl without pre-molded tunnels. If you are ﬁtting a
cowl with premolded exhaust tunnels, this opening must only
be large enough to allow the exhaust pipes to exit. The small
tube in this photo is the oil breather.

Universal Cowl with Aluminum Exhaust Tunnels.
If your universal cowling has aluminum exhaust tunnels in-
stalled, you will need to follow the installation outlined above
for "Cowl with Pre-molded (Fiberglass) Exhaust Tunnels".

Universal Cowl with No Exisiting Exhaust Tunnel
Fitting the 2-into-1 exhaust to a cowling with no existing
outlets is very simple.
A 4" x 12.5" cut-out is made on the lower aft edge of the cowl-
ing, where it attaches to the bottom of the ﬁrewall. This open-
ing provides both an outlet for the exhaust pipes as well as an
outlet for the engine's cooling air. No other cooling air outlets
should be added to the cowl.
Note: The loss of piano hinge in this area has no impact on the
strength and security of the cowl installation.
An aluminum exhaust lip must be added to the front of the
opening. The lip should be 1" high and rake back 60 degrees
from front to back.
A stainless steel deﬂector may be added to the bottom of the
fuselage ﬂoor to guide and deﬂect the exhaust gases.

This photo shows the standard outlet for a 2-into-1 exhaust
ﬁtted to a cowl without pre-molded tunnels. The cut-out
measures 4" x 12.5". No additional cowl outlets are needed for
cooling air. The small tube in this photo is the oil breather.