Wren Turbines Ltd. MW54 Mk2 & Mk3 Turbo-Jet, kit assembly instructions, Jun 2004
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motor bearings to last! If the clutch is even very slightly out of line it will drop out before the engine reaches self sustain and it will not start, or will
have a hot start. Make sure therefore the starter clutch is perfectly aligned with the compressor spinner nut.
With practice a start need take no more than 10-15 seconds.
Noises?
All jet engines make a lot of noise – especially at full throttle, a deafening fantastic roar defined as “whoosh” by turbine enthusiasts – hence the ear
defenders!
However, any unusual noises should be investigated immediately by shutting the engine down and close checking for rubbing – particularly the
turbine in the first couple of runs and around the compressor/intake cone. A few sparks are normal as the engine settles down, but be sure they are
not regular, caused by rubbing on the turbine. If the engine runs noisy, shut down and carefully feel the case as it runs down. If you feel vibration
the rotor is out of balance. If the engine makes a high pitch whistle whilst running, carefully touch the outer case with the metal part of a
screwdriver and feel the shank with your fingers. Again, if you feel a vibration the rotor is out of balance. Any penetrating noise that appears
greater at the front of the engine is likely to be a compressor rub. Stop the engine and check immediately, this fault never clears, as the inlet cone
picks up on the compressor and rubs harder, causing greater heat and more noise. Most noises are due to poor balance so be extra careful with this
operation.
The engine is highly responsive and unlike early model turbines has an almost instant increase in speed and very little throttle lag. This will aid flying
and make those overshoots easier! Do not exceed 160,000rpm.
Thrust.
When satisfied that there are no problems you can continue practising your starting and complete some thrust tests, and enjoy your handywork!!.
Due to variations inherent in the casting process which manifest themselves in fractional differences in turbine and NGV profiles, kit engines can
vary in thrust output from 5.5Kg to 6Kg (12lbs to 13lbs) for Mk2 engines and 6.2kg to 6.7kg (13.5-15lbs) for Mk3 engines.
Summary of Contents for MW54 Mk2
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