Jabiru Aircraft
Pty Ltd
Installation Manual
Jabiru 3300 Aircraft Engine
REVISION
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Dec 2016
Page: 35 of 56
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Exhaust System
An exhaust system is provided with the engine. Both Pusher and Tractor systems are available.
Muffler Volume
– Capacity 5 litres
Back pressure at Takeoff Performance
– Max 0.2 bar (2.9 psi). Readings taken 70mm from muffler flange
connections. Only complete mufflers supplied with Jabiru Aircraft are welded
– all others require tail pipes to
be TIG welded to the muffler body. NOTE: Drilled ends of pipes go inside muffler cavity. The tail pipes go
completely through the muffler body and are welded on both top and bottom.
When fitting the muffler one or more of the exhaust pipes can be loosened at the connection to the cylinder
head to allow easy fit of the muffler. They then must be tightened.
Exhaust Gas Temperature (EGT) limits are given in Section 1.5.7.
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Propeller & Spinner
The hub of the propeller must be drilled with holes to match the flange.
Fixed pitch wooden propellers are preferred. To safely use a propeller made of metal or composite a
crankshaft vibration resonance survey has to be conducted to ensure that there are no damaging vibrations.
Note that this refers to each new propeller design using composite or metal blades
– once proven the
propellers do not need to be tested for each individual installation. However, due to their inherent vibration
damping qualities, wooden propellers can be used without this testing.
Jabiru Aircraft now has a composite scimitar propeller which is the standard installation for new LSA and kit
aircraft. A vibration survey was conducted on this propeller design and the characteristics are known when
installed with a Jabiru engine within the range of typical pitch setting angles specified.
Wooden propellers require periodic inspections to maintain proper attachment bolt tension
– Typically every
50 or 100 hours, depending on the propeller manufacturer’s recommendations.
Belleville washers may be used as shown in Figure 39 to allow for expansion and contraction of Jabiru
wooden propellers.
The propeller must be carefully selected to match the airframe and the engine: Propellers up to 1778mm
(70
”) in diameter and between 762mm (30”) and 1397mm (55”) in pitch
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may be used. The propeller flange
is drilled with two sets of holes which can be used for propeller mounting. 6 holes at both 101.6mm (4”)
PCD and 111.12mm (4 3/8”) PCD (total of 12 holes).
The Jabiru Engine does not have a hydraulic pressure supply or a governor mounting pad required for a
hydraulic constant speed or variable propeller.
Propellers with excess pitch can cause high temperatures and engine damage. Nominally, all propellers
must be able to obtain 2800rpm static and 3150rpm to 3300rpm wide open throttle straight and level.
However, in some particularly low-drag airframes it may be necessary to use a propeller which does not
achieve 2800 static rpm. In these cases propellers should be chosen based on their RPM at wide open
throttle (straight and level flight).
Do not cruise or climb in the range 2100rpm
– 2400rpm.
Maximum moment of inertia 0.3 kgm
2
Applications outside this range should be referred to Jabiru.
WARNING
Engine MUST NEVER BE RUN WITHOUT THE PROPELLER. Damage
will occur in this state.
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Pitch measurements are taken from the angle of the rear face of the prop blade. Other propeller
manufacturers may specify pitch measured from the blade mean chord line or other reference. Make sure you
are comparing equivalent pitch units when specifying a propeller.