pilotweb.aero | Pilot June 2018 | 65Staples seem rather brutal, but
they leave a delicate hole which
doesn’t appear to weaken the rib
stock. Incidentally, the plans seem
to suggest leaving the staples in
place which perhaps made sense
in the 1930s when less reliable
organic glues were the norm.
My LAA inspector says synthetic
glues are now so good that staples
should be removed, not least
because they can start to rust
(and they do add infinitesimally
to weight).
A rib made this way seems
enormously strong in relation
to its weight. It is a small work
of art, and I particularly like
the glued-on biscuit method
of reinforcing a butt joint.
Similar joints−in the fuselage
at least−of my Stampe were
held together by complicated
fittings made from welded sheet
steel with lugs for bracing wires.
What a relief it must have been
to aircraft constructors when
plywood and reliable glues came
along. Plywood webs are used
to reinforce the joints at the
ends of the drag and anti-drag
wooden struts inside both the
tailplane and the wings in the
Wot. Other designs (such as the
Stampe, Flitzer and Pitts Special)
use bracing wires with bolted-on
metal fittings at each end.
(My inspector says the Wot
method is also used in wooden
glider wings.)
After making the ribs, I
assembled them and the other
components of the tailplane
on my work bench. The Wot’s
tailplane tips are constructed like
the wing tips on many aircraft,
from multiple laminations,
glued together over a former
to make a curved shape. Once
attached to the tailplane (all
joints reinforced with plywood
webs) the tips have to be planed
and sanded from a square cross-
section into one shaped like a
‘D’. This all went more or less to
plan, although the manual plane
I used was rather laborious.
Later I bought an electric planer,
which is not only faster, but
makes a lot less mess, because
the shavings are caught in a bag
attached to the machine.
The final stage in constructing
the tailplane was to glue on
the plywood leading edge, but,
before that, the whole thing had
to be given the okay by my LAA
inspector−essential, because he
wouldn’t be able to see inside
once it was covered in. The thin
plywood used on the Wot didn’t
need steaming; dampening it
with boiling water was sufficient
for it to take up the required
shape. I put towelling, then thick
polythene over the tailplane
and used that as a former. Left
overnight, in the morning the
plywood was curved and fully dry,
ready to be glued on.
First, it had to be cut to make
an exact fit. I attached it securely
at one end, stretched elastic
round it at each rib station, then
marked the other end with a
pencil−nervous stuff this, and
even more so when cutting the far
end and the edges with a Stanley
knife. Inevitably I didn’t get it
quite right. Make the plywood
a touch oversize and it won’t be
glued to the ribs properly. I made
it a smidgen undersize, which
my inspector said was acceptable
when he saw it a few weeks later.
It meant a very slight reduction in
the glued area where the plywood
attached to the front spar but, likeFeature | The slow-build Wot
THIS PAGE, TOP TO BOTTOM: mixing
a small batch of glue; master
templates for marking out the
plywood rib ‘biscuits’; stapling
ready glued biscuits in place and
the simple jig used for both
full- and nose ribs