plans or instructions. Many models are
designed from the beginning with that
particular manufacturer’s gear in mind.
Currently, there are only two choices for
manufacturing landing gear that can be
considered scale or “darn close scale.” They
are Sierra Giant Scale ( sierragiant.com) and
Robart Mfg. ( robart.com). Both companies
also offer scale metal wheels and tires.
Once the landing gear, wheels, and tire
selections have been made, you should
start thinking about which engine you’d
like to use.
The engine fit is most important to
many scale modelers. By that I mean that
they’d rather not have a large portion of
the cylinder head sticking out of the cowl
or fuselage, and they especially don’t
want to chop big holes in their fiberglass
cowls to clear the muffler or carburetor.
In many cases, you might need to look
at the engine’s design for things like the
carburetor placement, muffler routing, and
carburetor linkage. Some radial-engine
airplanes can use opposed twin-cylinder
engines to great advantage. Some can even
use one of the new 4-cylinder engines,
while other designs will have room for
streamlined in-line twin-cylinder engines.
Big round-nose planes will accommodate
one of the healthy but expensive
multicylinder radial engines.
Where do we go for engines? I was afraid
that you’d ask that. For years, Zenoah
( horizonhobby.com) has been the
place everyone went to. Simple, fairly
powerful, and easy to afford, its line has
recently been upgraded with electronic
ignition systems. I’m currently having a
lot of success with several gas engines,
including Desert Aircraft (desertaircraft.
com); 3W ( aircraftinternational.com); ZDZ
( troybuiltmodels.com); Aircraft Modelers
Research ( amr-rc.com); DLE engines
from Hobbico ( hobbico.com); and two
radial designs, one from Moki (vogelsang-
aeroscale.com) and the other from
Evolution ( horizonhobby.com). Most of
these companies have a choice of mufflers,
either straight type or a wraparound
(Pitts-style) to get the exhaust out of the
cowl without forcing you to gouge huge
holes in the fiberglass. And if they don’t,
JTec Radiowave ( jtecrc.com) can make you
exactly what you need.
When it comes to fuel tanks, I use
nothing but RotoFlow tanks from J&L
Power Products ( jlproducts.net). They
negate any chance of a kinked fuel feed
from inside the tank, tubing falling off
of nipples, and any other internal tank
One last thing is my choice of spinners
or prop hub nuts. I usually contact
Gene Barton of Gene Barton Machining
( genebarton.com) in Missouri because
he can make just about anything from
metal. If Gene is busy, I’ll use Dave Brown
Products ( dbproducts.com) or Tru- Turn
Precision Model Products ( truturn.com) if
they have what I need.
As you’re building, you’ll sometimes need
to install a servo and its linkage. You’ll,
perhaps, remove them when it’s time
to paint, but getting everything set up
beforehand is a good idea. The only place
that we might be practicing a bit of overkill
is in the servo selection. What we need to
remain aware of is to use the proper size
and power servo in the right place. I always
use digital servos and those that operate
at a minimum of 6 volts (up to 7 or 8 volts),
and I never continue to use any servo that
has glitched—even once. I use American
hardware—Du-Bro is my favorite—and I
try to avoid Chinese accessories, if at all
possible. I stay away from anything metric,
unless it is an absolute necessity. It is a
great idea (make it a practice) to have all
linkages incorporate the best mechanical
advantage (with no slop) at either end.
Use 4-40 hardware and clevises, and stay
away from 2-56 on any model that has
more than a 80-inch span or is more than
22 pounds in weight. Use thread-lock,
like Pacer Z- 42, on all metal fasteners to
prevent vibration from loosening them.
And if the servo manufacturer offers
heavy-duty servo output arms, buy some!
If they don’t, contact Du-Bro.
I think this gives you some idea of
what’s involved to present a good-looking, sound-flying model for scale
competition. In an upcoming article, I’ll
talk about finishing, color and markings,
and the documentation you’ll need for
I arranged for operating cowl flaps—not a job for the meek! I have a friend in Brazil who, for slightly less than a
month’s rent, will make your cowl flaps operative. Mine open when the gear is down and close when the gear is
retracted. I can put you in touch.
My last Thunderbolt, which
now resides in Brazil, shows
the scheme that I will probably
duplicate—especially since I
have so much data on it!