Jabiru Aircraft
Pty Ltd
Installation Manual
Jabiru 3300 Aircraft Engine
REVISION
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Dec 2016
Page: 49 of 56
Figure 54. Oil Cooler Duct Design
Figure 55. Oil Cooler Installation
12.5
Air Outlet
As the sections above describe, getting air out of the cowling is often the factor limiting how much air can be
pushed through the engine and how well it is cooled.
The shape of the outlet of the cowls controls how effectively air is sucked out of the cowling and is arguably
the single most important aspect of cowling design.
As noted above, as a rule of thumb the cowl outlet area should be at least 3 times the combined area of all
the cowl inlets.
Figure 56 shows a small lip added to the rear of the cowls of a Jabiru Aircraft. This lip gives a large
improvement to pressure differentials and engine cooling.
Airflow in
Controlled gap “leaking” air
over the sump and lower
parts of the engine.
Oil Cooler
