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Jabiru J450 Constructors Manual
Testing>Flight testing
Tuesday, April 6, 2010
334 of 343
Test fit the eccentric bush into the wing lug dry, using a gently tapered object such as an old
round file through the centre of the bush to screw the bush into the lug, ending when the bush
is centred in the lug with offset hole facing UP to test the threads. Remove the bush.
Mix a very small batch of resin and separate it into 2 portions and then use one portion to coat
the thread in the bush mounting hole in the wing lug and then coat the outside of the eccentric
bush. Add flock to the other portion and apply a small amount to the bush and then screw the
bush back into the lug, ending when the bush is centred in the lug with offset hole facing UP.
Wipe away all excess flock and lower the wing lug and bush back into the fuselage lugs and
place the length of wire through the holes in the lugs and the bush.
Repeat the process for the rear bush, first test fitting the bush dry and then fitting it with resin
and flock, but this time end with the offset hole in the bush facing DOWN.
Wipe away all excess flock and lower the wing lug and bush back into the fuselage lugs and
hold in place with the wire. Leave the flock overnight to cure.
The next day fit the wing bolt though the lugs and the new bush. Refit the flat washers to the
bolts as before. Remove the wire from the front bush and refit the wing bolt and flat washers.
Fit
new
Nyloc nuts to each wing bolt and tighten to safety. Do
not
reuse these nuts.
DO NOT OVERTIGHTEN THESE BOLTS. They should be just tight enough to prevent
rotation. Over tightening may result in failure of the wing attach lugs.
Refit the wing root fairings. Retest the aircraft and, if required, make any small roll
corrections by adjusting each flap individually.
4. Adjusting the Flaps
Use this procedure if the aircraft shows a tendency to roll in straight and level flight and
not
just before the point of stall in a clean configuration as mentioned in the previous step then
minor adjustments may be made to each flap individually.
If the aircraft rolls to the left then the left flap may be lowered slightly, or the right flap may
be raised slightly. If the aircraft rolls to the right then the right flap may be lowered slightly,
or the left flap may be raised slightly.
Remove the wing root fairings as required to gain access to the flap pushrods. Remove the rod
end connecting bolt from the drive yoke, loosen the lock nut and move the top rod end in or
out and then refit the rod end to the drive yoke, tighten the lock nut. Refit the wing root
fairings before each test flight.
It is not possible to predict the amount of adjustment required as each case will be different,
but as a general guide try moving a rod end one full turn and then test fly that configuration to
see if more or less adjustment is required. Take careful note of each change and the effect on
the flying qualities of the aircraft.
If, for example, down adjustment becomes a problem on one flap then adjust the other flap up.
If it becomes necessary to adjust the flap end of the pushrod, remove the flap to do so.
Care
must
be taken: the threaded end of the rod end must always be visible through the safety
holes in each end of the pushrod, the rod end lock nuts must be tightened against each end of
the pushrod and the Nyloc nut on the connecting bolt through the drive yoke should be
replaced before each test flight.