MODULAR DESIGN
Maintenance on the ladder-style frames used by most RC
bikes can be a pain, but the R30FS’ modular design gives
much improved access to the various components. Need
to drop the engine or do some clutch work? Remove the
fuel tank (one screw), two screws from the carb adapter
(the carb and adapter stay in the frame), two more screws
for the engine mount, and disconnect the header nut.
That’s all there is to it. The jackshaft, on which the flywheel
and clutch are mounted, is clamped to the crankcase, and
all comes off in one piece. Need to tear down the tail?
Disconnect the servo and battery leads, remove two
screws from the pipe hanger and four more for the tail
itself, and the rear comes off; the shock even stays in place
with the main frame. Everything on the bike is like that,
even the swing arm, and it all can be torn down without
having to call Jimmy the assistant over for another pair of
hands. You get the idea.
REALISTIC LAYOUT
A sense of scale realism was high on the priority list for
Nolan, and part of this was having the fuel tank up top,
where it would be on a full-size bike. This posed a few
problems, the first of which was that no one had an off-the-
shelf tank that would work. So Nolan designed one of his
own— machined in two pieces, not molded. You read cor-
rectly, the upper and lower pieces are machined and then
heat-sealed together for a leak-free tank. To prevent gravity
from doing too good a job with the fuel flow, a fuel pressure
regulator is placed between the tank and the carb. This not
only keeps a constant feed of fuel to the carb under vacu-
um, but it also closes like a siphon valve when no vacuum
is present. The toughest trick was to get the large O.S.
4-stroke into a 1⁄5-scale frame. Clever packaging is key, and
industrial design is Nolan’s specialty. First, he designed an
entire new head, incorporating a free-flowing high-perform-
ance design underneath the covers. This allowed him to
place the carb (a standard O.S. 10e rotary unit) exactly
where he wanted it—right under the tank next to the ser-
vos. This was no small feat, as it takes dozens of machine
hours to get the cuts just right. This is the main hurdle to
putting the R30FS into full production.
PULSING POWER
The most notable performance attribute of the R30FS is
that it has amazing cornering speed, especially when com-
pared with the electric motorcycles that I race with regu-
larly. Forget acceleration, forget top speed—cornering is
where RC bike races are won (and lost). The biggest factor
in corner performance is mechanical grip, which is aided
by the nature of the 4-stroke’s power delivery. Because a
4-stroke engine combusts fuel and air on every other crank
revolution, it has a low-frequency pulsing power delivery.
This creates a bite/release/bite/release cycle at the rear
tire’s contact patch, kind of like the way a full-size car’s
ABS system works to achieve more overall traction.
Compared with a 2-stroke motor (which combusts its
fuel/air mixture every time the piston reaches the top of its
stroke), or an electric motor (which runs at frequencies so
high that it has no real “pulse”), the thumper’s usable low-
end power and traction-assisting nature make it a perfect
