The craftsmanship on Bob Underwood’s 1/3-scale 1939 Bonzo racer is
amazing. Full-scale aircraft of this era had long fuselages and short wings
designed for racing.
A view of the top of
Bob’s Bonzo racer. The
full-scale Bonzo was
built by Steve Wittman
in the 1930s.
Bob Underwood’s Bonzo racer
by Stan Alexander
Different eras of aviation interest modelers around the world. Some are huge warbird fans, while others are jet crazy. Some like the Golden Age of aviation, but
others try to find something different.
Bob Underwood made a scale modeling career out of
building something different. Most projects he finished,
some he didn’t, and others have never been started.
In the 1970s, Bob built his first Wittman D- 12 Bonzo
racer. The full-scale Bonzo was built and raced by EAA
pioneer Steve Wittman in the 1930s. When racing resumed
after World War II, Steve continued to race airplanes.
sizes of the
the first one
had “the glide
ratio of a
brick.” As he
a lower wing
When Bob retired from competition, I acquired his
unfinished 1/3-scale model of the 1939 Bonzo racer. The
aircraft has a 72-inch wingspan and is 89 inches long—well,
at this point, that’s close. We both want to see the model fly
and I’ll try to finish it for the upcoming National Association
of Scale Aeromodeling (NASA) Scale Classic in Lexington,
Kentucky, this fall.
The earliest iteration of the Bonzo was not as pretty as
the 1939 version! The one displayed in the EAA Museum
in Oshkosh, Wisconsin, is the 1938 version … sort of. It has
been prettied up with a super-glossy Imron paint job and a
few things are composites of the 1938 and 1939 versions. Like
many racers, Steve Wittman continually changed the airframe,
engine, propeller, or anything else he could think of to try to
obtain an edge on the competition.
There are several other aircraft from that era that I enjoy,
including the Gee Bee racers and Art Chester’s Goon (similar
to the Bonzo), as well as the Chester Jeep. There are plans
out there for most of these, and now Sig Manufacturing is
exclusively importing Seagull Models,
including the Gee Bee Z ARF.
There are plenty of aircraft to model. If
you have one and want to share, send me
pictures and information about what you’re working on or
have finished. I have a story this month about a modeler who
rebuilt a sort-of crashed Piper PA- 18 Super Cub.
Scale Techniques and Tips
Needing a box to carry the fuselage and work on the Bonzo,
I purchased a 4 x 8-inch sheet of 3/8-inch foam insulation from
Home Depot. It cuts to shape easily and you can make pretty
much whatever you want with it. I wanted to make the entire
box out of this one sheet of foam and managed to do so.
The cutouts are lined with pipe insulation to protect the
airplane while it’s transported in its cradle. I used Liquid Nails
adhesive to hold it together. Apply it liberally, wipe off any
excess, and allow it to dry for 24 hours.
The 2015 Scale Nats will be held July 17-19 at AMA’s
International Aeromodeling Center, in Muncie, Indiana.
One of the things I enjoy about Scale competition, whether
101 Model Aviation JUNE 2015 www.ModelAviation.com