MAULE AEROSPACE TECHNOLOGY, INC.
MAINTENANCE MANUAL
FOR
MX-7-420
17
Rev. A
RIGGING PROCEDURES
1. LEVELING:
Laterally: The airplane can be accurately leveled laterally using the front spar attach
bolts. Turn these two bolts so that a flat on the head is "up". Fabricate two
equal length spacers (1½ inch minimum length) which can be placed on the
bolt heads. Place a 48 inch level across the two spacers and block under the
landing gear to center the bubble.
Longitudinally: Using a level thirty-six (36) inches long or longer, place it on the leveling
lug and leveling mark thirty-one (31) inches to the rear of the leveling lug
on the bottom of the right wing root. Raise the tail to bring bubble to cen-
ter.
2. DIHEDRAL ANGLE:
To check dihedral angle at the front spar, remove both top wing root fairings to ex-
pose the front spar attach bolts. Stretch a string along the top of the wing above the
front spar, from wingtip to wingtip, and draw it tight. The end of the string can be at-
tached to tie down fittings underneath the wing to hold tautness. Be careful to protect the
edges of the wingtips from string chafing.
Find the row of flush rivets on the top of each wing from wingtip to wingtip at the front
spar location. Measure from the forward wing to fuselage attach bolt centerline, for both
left and right wings, outboard 127.5 inches along the top of each front wing spar. Using
masking tape or equivalent, tape the string down on the rivet centerline at this point.
At the inboard end of the front spar, measure the distance from the top rear edge of
the spar cap to the string on both wings. Adjust the front wing struts so as to have a
measurement of 2 3/4 inches on each wing (plus or minus 1/8 inch) at this location. It is
recommended that the rear struts be removed while adjusting dihedral. The wing must
be supported while the front strut is being adjusted. For rear strut adjustment, see sec-
tion on Washout.
CAUTION: Be sure that the strut fork is not extended more than 1 inch of threads from
the strut end to the end of the fork threads (not including the jam nut). There must be at
least 1 3/8 inch of thread engagement into the strut.
3. WASHOUT:
To adjust the washout in the wings, proceed as follows:
Put a leveling protractor chordwise on the underside of the wing root and adjust it to
a zero degree reading. Now put the protractor chordwise just inboard of the wing tip
and adjust the rear strut to give ½
°
trailing edge up, difference from the wing root angle.
