19
As with setting the angle of incidence, the
goal of setting the dihedral isn’t so much that you
hit exactly one degree but that both wings be as
close to being exactly the same as possible.
Everything having to do with rigging the airplane
after you get it flying is made a thousand times eas-
ier, if the airplane is symmetrical about the center-
line.
Order of Operations
Once the wings are in place on the fuselage,
as in the last section, the steps to be taken are:
1. Double check the fuselage for being level
in both directions.
2. Set the wing dihedral on each side
3. Trim the strut material to length
4. Squeeze the strut ends down to accept the
fittings.
5. Temporarily hang struts on airplane
6. Mark fittings
7. Remove and drill holes for bottom fitting
in one side of strut only. ALL HOLES ARE ON
ONE SIDE OF STRUT ONLY UNTIL LAST
OPERATION.
8. Put back on airplane with bottom fitting
bolted to outside of strut but top fitting clamped.
Recheck lengthwise position of fitting.
9. Remove, drill one hole for top fitting and
bolt.
10. Reinstall and clamp top fitting in posi-
tion and mark.
11. Remove and drill another
hole for the top fitting.
12. Reinstall for one last
check
13. Remove, drill rest of
holes in one side of strut only.
14. Insert fittings inside strut
and use fitting to guide drill through
other side of strut.
12. Insert final bolts and
you’re finished.
Level the Fuselage
Yeah, we know, we leveled
it in last section but level it again.
The accuracy of your dihedral,
which also determines your rig-
ging, will depend on having the fuselage level.
We’re going to recheck it several more times dur-
ing the process of building the wing struts.
Set the Dihedral
The plans call for 1 degree of dihedral,
which is 2.9” (2 29/32”) difference from the root to
the tip. But the truth is it doesn’t have to be that
exact. In fact, round it up to 3.0” to make measur-
ing easier. The easiest places to measure that and be
accurate are at the edges of the lower skin where it
hits the main spar at both ends.
Set the water level up with one end right at
the lower skin next to the fuselage and the other
end suspended from the outer end of the skin with
a clamp of some sort. Just tape the tube to the
clamp and adjust things until the water at the inner
end is exactly level with the bottom edge of the
skin.
An excellent alternative to the water level is
to use a 3’ bubble level with a 5/8” block at one
end. Set it on the top skin, over the main spar.
ALL OF THIS ASSUMES YOU HAVE
THE FUSELAGE EXACTLY LEVEL. IF IT’S
NOT LEVEL, NONE OF THIS WILL WORK.
Using the sheet rock lifts or a 2 x 4 “T”,
adjust everything until there is exactly 2 29/32”
between the level of the water in the outer end of
the tube and the skin at the spar.
So you aren’t driving yourself nuts trying to
A water level is set up so you can measure exactly 2 29/32” (3.0” is close enough)
rise, root to tip. Measure at the edges of the bottom skin where it comes across the
bottom of the main spar.
Wings: Setting the Dihedral and Making the Struts
Summary of Contents for Bearhawk N33RB
Page 1: ......