Attaching Wings to Biplanes
One thing that puts some people off building biplanes is the difficulty
in attaching the wings, ensuring the incidence angles are correct,
and everything is square. The method described below is now my
standard procedure for biplanes - it is fairly simple and pretty well
foolproof so maybe it will encourage you to build that extra set of
As an example, I will take my Dime Scale Stearman 76 again, which
features a one-piece upper wing, and two lower wings butt-joined
to the fuselage sides.
Using a photocopy of the plan, with the correct incidence angle drawn
in, a template was cut out, representing the space between the bottom
of the upper wing centre section and the top of the fuselage. The
position of the wing leading edge was marked by a step, and the
positions of the fuselage formers, plus the front of the cockpit
noted. The paper cut from the plan was glued to a bit of thin card,
then tacked onto the fuselage, along the top stringer, using a couple
of dots of PVA.
When dry, the wing was tacked to the top of the template along the
centre rib, again with PVA, positioned with the LE at the correct
position. To keep the wing level when viewed from the front, a pair
of temporary balsa struts were tacked into place, from the lower
fuselage to somewhere under the outer wing panels.
You now have a sort of parasol arrangement, which will be rigid
enough to stay in place while you add the four centre section struts
one at a time. The plan shows 1/16" square balsa for these, but I
used cocktail sticks for strength. These had been previously covered
in blue tissue, to match the fuselage, and were attached using cyano.
Once the struts were fully set, the jig and temporary supports were
removed after softening the PVA with a wet paint brush.
To correctly space the upper and lower wings and set the stagger,
another jig was cut out, to slip over the tips of both wings. This
also keeps them at the same incidence while the lower wing is glued
to the fuselage side. The model must be viewed from above to check
the wings are parallel.
The wings will have enough spring in them to allow the later addition
of the hard balsa interplane struts, though it is best to slip the
jig over the wings again once you have done this to recheck the angle
If you are building a model where the lower wing is a one-piece affair
that passes under or through the fuselage, then this will be fitted in
place before the upper wing. This means the second wing-spacing jig
will probably not be needed (though you could still make one to check
the relative incidence angles of the wings). In the photo below, my Boeing
F4B-2 has its upper wing mounted on a jig, exactly as per the Stearman, but steadied
using thin balsa strips connecting it to the previously attached lower wing. Two of the centre
section struts had been already added when the picture was taken.
Returning to the Stearman - this was finally rigged with fishing nylon, attached with cyano.
This "working rigging" has the effect of strengthening the structure
considerably. When the photo below was taken, immediately prior to the first test flights, the
rear gun and windshields had yet to be fitted
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