FB Jets FEI BAO, Assembly Manual

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Step 13: Engine Rails, Bypass and Pipe
Clean the fuselage thoroughly before installing the engine. If you need to trim the intake for
engine clearance, use a vacuum while you work. This will reduce the chance of having a
foreign object finding its way into your engine.
It is the builders choice as to use the supplied full bypass for your installation; however if you
choose not to use the full bypass then it is suggested to use at least the bottom half of the
bypass, this will create a barrier between the hot parts of the turbine and the pneumatic line
used in your aircraft.
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Drill two holes on each side of the pipe mounting tabs. The first should be just in front of the
pipe mouth, the other approximately 50 mm further forward.
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The tabs are positioned just above the centerline of the pipe and this is the top. Insert the
pipe into the fuselage and position the aft end about 5 mm from the end of the exhaust
cones.
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Place the lower bypass on the engine mounting rails. Slip the pipe forward over the aft end
of the bypass. You may need to slightly trim the lower former a bit to allow the bypass to
move far enough aft to keep the rear of the pipes in position.
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Position your engine on the mounting rails. Set the gap between the rear of the exhaust
cone and the mouth of the pipe to manufacturer’s specifications. This is usually around 20
mm. You may need to trim some material off the intakes to allow the engine to sit far
enough forward.
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If required, marks the bypass for the positions of the engine mounting tabs and trim away
material such that the engine exhaust is centered on the pipe. Shims may be required
under the front engine mounting tab to insure that the angle of the engine is on line with the
angle of thrust line of the pipe.
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When you are satisfied, bolt the engine to the side frames; you can use appropriately sized
wood screws or install blind nuts. If using wood screws install the screws and then remove,
then coat the thread holes with thin CA. This will harden the wood around the screw holes
themselves. Permanently reinstall the engine mounting screws.
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Drill and secure the bypass to the engine mounting rails with four wood screws.
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Finally, drill the rear of the bypass for the pipe mounting straps and bolt in place. The heads
of the bolts should be on the inside of the bypass.
Photo 92