Quickie Q2 Lite Construction Manual - page 265
ENGINE BAFFLING
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The purpose of the engine baffling is to provide adequate
airflow for cooling to all critical areas of the engine and
accessories. Air enters through the cowling air inlets located on
either side of the spinner. A vertical baffle located in front of the
forward engine cylinders forces the incoming air to travel upward
across the cylinders and then down through the fins, exiting the
bottom of the cowling through the variable opening cowl flap. Another
vertical baffle located just aft of the rear cylinders assists in
forcing the air down through the cylinder fins. Likewise, baffling
between the cylinders and the sides of the cowling performs the same
function. An opening in the forward vertical baffle allows airflow
into the oil cooler. Once having passed through the oil cooler, this
air mixes with the spent cylinder fin air to exit through the cowl
flap.
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Aluminum with an 0.032" thickness is the primary baffle
material. Approximate full size patterns are provided. However, there
is no easy way to fit baffling around the complex shape of the
engine. Areas of leakage must be closed off with aluminum in the case
of large holes, and silicone in the case of small leaks. The black
rubber asbestos is used between the aluminum and the cowling to
provide a close fit when the cowling is installed. Pop rivets (BSP42)
are used to join the pieces of baffling and asbestos together. Small
angles can be bent up from the 0.03211 thick aluminum to attach the
baffles to bolts on the engine painted red. In this manner, the
baffling will be removable.
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Baffling can easily consume 10 man hours of work, so don't
hurry. Inadequate cooling is a major factor in many homebuilt
aircraft engine problems.