Yak 18T Flight Operations Manual
Page 30 of 82
Disclaimer: This manual is to be used as a reference only, it is based on translated Yak 18T Flight Operations
Manuals and has not been approved by the Yakovlev Design Bureau or any other authority.
Section 6 – Engine Start
At ambient temperatures of +5°C or less, the engine must be warmed-up from an airfield
heater, to a cylinder head temperature of at least 30°C. In this case, it should be quite easy
to turn the engine propeller through by hand.
If the ambient temperature is between +5°C-10°C and if the oil in the engine and oil system
is diluted with petrol then the engine can be started having not been warmed-up. The
engine can either be started from the aircraft accumulator or from the airfield power source.
CAUTION
• DO NOT turn the propeller when the engine is hot i.e. > 100°C (lower to be safer)
• DO NOT fill petrol up above the amount specified, as it can wash oil off the cylinder walls
and cause a score of the pistons or can be accumulated in the bottom cylinders and also
contribute to a hydraulic shock
• DO NOT fill the petrol up through exhaust branch pipes and spark-plug ports
6.1. Prior to Starting the Engine
• CHECK that the propeller pitch lever is placed in the FINE PITCH position
• SET the thrust lever to the position corresponding to 1/3
rd
of fully open equivalent
to approx. 28-38% engine rpm
• ENSURE that the fuel cut-off valve is in the open position i.e. FULLY FORWARD
• at ambient temperatures below zero, SET the carburettor heat control lever (adjusts
air getting into the carburettor) to the ON position (i.e. fully downwards)
6.2. Avoiding Hydraulic Shock
• CHECK that the engine was shutdown using the correct procedure i.e. run at 60%
for at least 30 seconds at the correct temperature setting – if not, it is advisable to
drain the bottom three cylinders for hydraulic shock avoidance
• TURN the propeller through until the oil that may drip from the exhausts ceases
completely. This may take several revolutions
• Now WAIT for the oil to stop dripping completely and then turn the propeller
through a few more times looking for signs of further oil expulsion from the cylinders
and repeat if necessary
6.3. Engine Priming
• TURN propeller (3-4 revolutions); during the propeller turning, SET the primer
MOTOR PRIMING to the CYLINDER position and fill up 2-3 primers of petrol into the
engine cylinders in summer and 3-5 primers in winter time.
• GOOD ADVICE, but this is a tad difficult if you are on your own! Prime the cylinder,
turn the propeller, prime the cylinder, turn the propeller, prime the cylinder and turn
the propeller. Laborious but necessary and “Yes”, you do need to get in and out of
the cockpit each time. Also, if you are on wet and muddy ground, you need to think
about cabin cleanliness too
• Now SET the MOTOR PRIMING primer to the FUEL LINE position and GENERATE
the fuel pressure in front of the carburettor to 0.2 to 0.5 kgf/cm²
• NOTE: this pressure will drop with time and may need to be restored prior to start –
DO NOT over prime more than 0.5kgf/cm²
• upon completion, SET the primer back to the CYLINDER position ready to provide
additional fuel into the cylinders upon starting (i.e. the primer should be pulled out)
To Next Page
Loading...