AOPA Pilot Magazine - May 2024 - 64

reminiscent of larger, far more expensive,
radial-engine Waco biplanes that had
captured the imagination of pilots since
the 1930s. In 1986, a Hatz biplane built
by Rich Hansen raised the design's profile
when it won Grand Champion honors
at EAA AirVenture.
About 150 Hatz biplanes have been
built and flown over the years, and the
Hatz Biplane Association sells plans for
them, not kits.
Cilliers and Van Lehn made one big
departure from the Hatz norm in their
choice of engines. They decided early
on to use a Rotec R2800 radial from
Australia, a nine-cylinder, 150-horsepower
engine selected for purely
romantic reasons.
" There's just something uniquely
appealing about a radial-engine
biplane that's indescribable, " Cilliers
said. " Most of my decisions involved
in building an airplane are practical
and technical. The choice of this radial
engine was purely emotional. "
The two builders worked together,
mostly at home workshops, for the first
two years of construction producing an
inventory of sub-assemblies. Their strategy
of building side by side moved into high
gear while fabricating the wood wings.
There were eight wings to make in
total, and their learning curve was steep
at first. It generally took each of them
about one full day to make a single rib.
But they soon streamlined their process
into a slow-motion assembly line.
" It took us about a month to get the
first wing together, " Van Lehn said. " It
only took us a few days to do the last one. "
Aesthetic eye
The most difficult piece to fabricate was
also the one that sets their airplanes
apart: a metal speed ring that encircles
the radial engine.
Contrary to its name, the speed ring
doesn't make the airplane fly faster. But
it sure improves the looks, and Cilliers,
the metal perfectionist, wanted it to be a
gleaming work of art.
" I'd never used an English wheel
before, " he said of the painstaking,
64
AOPA PILOT / May 2024
frustrating-to-use, medieval-looking apparatus
that, in the right hands, can pound a
flat piece of metal into a smooth, complex
shape. " But I kept at it and kept at it until
I was satisfied with the result. "
Cilliers discarded his first couple of
attempts before finishing the two that
adorn both the airplanes now.
" We had very few remakes during the
construction process, " Van Lehn said.
" But the speed rings had to be done more
than once to meet Carlo's standard. "
Cilliers and Van Lehn have very different
styles.
Cilliers jumps into each task and is
comfortable with improvisation. He likes
action and often figures things out along
the way.
Van Lehn is a planner. He looks
before he leaps.
They also learned a great deal about
each other. Cilliers will keep working as
long as there's ginger beer to drink. Van
Lehn relies on a variety of rock music from
Spotify for motivation.
" You get to know a person's thought
patterns and personality when you build
airplanes together, " Cilliers said. " Rick has
an aesthetic eye and he's got a sense about
the details that make an airplane look
good. I don't have that kind of sensibility. "
The two made most of their big decisions
through consensus. They both
wanted radial engines and bought them
new as a pair. They also wanted Dynon
glass-panel avionics even though the
modern instruments are anathema to
biplane purists.
" The glass panel was actually a nobrainer, "
Cilliers said. " We're right next
to the Washington, D.C., airspace so you
want to know exactly where you are all the
time. And modern avionics are lighter and
far more reliable than old analog gauges.
We had to have glass panels, even if meant
the purists would disown us. "
They also weren't focused on winning
awards from judges who often place
a heavy emphasis on historical accuracy.
They wanted to build airplanes that they
could enjoy flying on a regular basis.
" We're not here to please the purists, "
Cilliers said. " We're here to please us. "
These Hatz biplanes have
parts and accessories from
at least four continents. Their
Rotec radial engines were
purchased new from the
Australian manufacturer; MT
fixed-pitch propellers came from
Germany and the varnished
wood laminations can be seen
and appreciated. The waterfall
Bubinga wood in the front and
rear cockpits was imported from
West Africa.
AOPA Pilot Magazine - May 2024

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