Rotax MMH-912 Series, Руководство по обслуживанию

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Effectivity 912/914 Series
Edition 1 / Rev. 3
78-00-00
page 3
October 01/2010
d04781
BRP-Powertrain
Maintenance Manual
2.) Systems description
2.1) Exhaust system (on the 912 Series)
On ROTAX engines of the 912 Series, the exhaust system is not included in the
ROTAX range of delivery. The engine is supplied only with the 4 exhaust sockets
on the cylinder head.
The exhaust system must be configured or manufactured by the aircraft or
fuselage manufacturer.
For disassembly, inspection and assembly of the exhaust system, observe the
aircraft manufacturers instructions.
The exhaust muffler part no. 973670 especially designed for the ROTAX
engines 912 S / ULS can be used also on the ROTAX engines 912 UL / A / F.
Engine performance and specific fuel consumption remain unchanged or are
slightly better when using this muffler part no. 973670.
The main advantage is the weight reduction. The weight is 2,2 kg, making this
muffler 0,3 kg lighter than the muffler part no. 978482.
By optimizing the design of the muffler part no. 973670 the noise emission may
seem subjectively higher compared with muffler part no. 978482. The exact
measuring of the actual noise emission can be conducted only when the muffler
is installed in the aircraft.
2.2) Exhaust system (on the 914 Series)
The exhaust system on ROTAX engines of the 914 Series collects all gases
which accumulate in the combustion chamber of the cylinders and routes them
via exhaust bends and exhaust manifold to the exhaust turbocharger. There, the
combustion gases drive the exhaust gas turbine to achieve a power increase.
See 78-00-00 sec. 2.3. From the exhaust turbocharger, the combustion gases
are routed to the muffler, which is fitted for noise reduction.
The exhaust system is made of stainless steel. The exhaust bend is connected
to the exhaust manifold by means of slide sleeves to ensure that expansion due
to heat can be compensated for.
The exhaust bends are sealed to the cylinder head by the ridge on the exhaust
bends. The muffler is supported via the exhaust bracket on the engine
suspension frame.
Owing to continuous further development, the exhaust bends were slightly re-
worked. The couplings were optimized for their position.
Position of the EGT connections to the exhaust bends for cylinders 3 and 4 were
routed such that installation of the new drip trays is possible.