Modifying the hatch to install other sizes of
batteries requires cutting a spare piece of
balsa to width. See the text for details.
After gluing the spare balsa piece in position,
cut away the crossbrace as shown. See the text
Model type: Sport ARF
Skill level: Intermediate
Wingspan: 47.5 inches
Wing area: 392 square inches
Length: 42. 5 inches
Weight: 4 to 4. 25 pounds
Power system: Two RimFire . 10 brushless
motors; two 25-amp
brushless ESCs; 3S 3,800
mAh LiPo battery
Radio: Minimum four-channel
transmitter and receiver;
four micro servos
Street price: $139.98
TEST-MODEL DE TAILS
Radio system: Tactic TTX850 transmitter;
Tactic TR625 receiver;
four S3115 Futaba servos;
two Futaba Y harnesses;
and two 12-inch servo
Power system Two RimFire . 10 brushless
used: motors; two 25-amp
brushless ESCs; 3S 3,800
mAh LiPo battery
Flying weight: 3. 75 pounds
Flight duration: 6 to 10 minutes
• Laser-cut balsa and plywood used for
• Includes all control hardware, wheels, and
fiberglass wheel pants and cowl.
• Airframe comes precovered with
MonoKote iron-on film.
• Vacuum-formed nose is painted to match
• Firewalls are predrilled for the RimFire
motors and include preinstalled T-nuts.
• The front “cockpit” area is a removable
hatch held in place with magnets, allowing
quick access to swap out battery packs.
• It can go from the box to ready-to-fly in
roughly 5 hours.
• The design limits the physical size of
batteries that can be used. I’ve outlined a
quick, easy modification that forgoes this
AT A GLANCE ...
the pushrods. This makes lining up the
servos simple. They are then mounted to
the preinstalled laser-cut radio tray.
Finishing the radio installation is
simply a matter of attaching the clevises
and control horns for the tail surfaces
then running the pushrod through the
forward part of the fuselage for the
steerable nose gear. Plug everything into
the receiver and attach it to the side
with some of the supplied hook-and-loop tape.
Only a few steps remain to complete
the Twinstar’s assembly. One is to attach
the nose cone. A notch needs to be
marked then cut into the bottom of it
so it will clear the nose gear. When you
are satisfied with the clearance, the nose
cone can either be glued in place or held
on with a couple of strips of clear tape. I
chose the latter.
A large sheet of pressure-sensitive
stickers is included, leaving it up to the
builder as to how realistic the Twinstar
should look. Applying them gave my
Twinstar a Cessna 310-like look.
After everything was in place, it was
time to check the center of gravity
(CG). I popped open the magnetic
hatch, strapped the supplied FlightPower
3S 3,800 mAh LiPo battery pack in
position, and was pleased to find that
it was nearly spot on. Moving the
pack slightly gave me exactly the right
balance. The all-up weight came in at
33/4 pounds—roughly 1/2 pound lighter
than called for in the manual.
Before I get to the flying portion,
there’s one restriction I wanted to
overcome that limits the physical size
of the battery that can be used. As
supplied, the Twinstar’s hatch allows you
to use only a 1-inch or thinner battery.
Anything thicker than that will not
allow the hatch to properly seat. That’s
fine if you use FlightPower or similar
batteries, but I have a number of 3S
4,200 packs from another manufacturer
that are thicker.
The source of the problem is the
bottom crossbrace at the rear of the
hatch. It must be moved—well, replaced
is a better description. To make this
modification, trim a spare piece of 1/16-
inch balsa sheet to 3 inches long. (I used
a 1/2-inch-wide strip.) Glue this piece
across the back bracing, roughly 3/8 inch
up from the crossbraces. After the glue
cures, use a hobby knife or saw to cut
away the original as shown. This will
give you extra clearance for a wider
range of batteries.
I don’t recommend trying to wedge
4S or larger packs in by using this
modification. They aren’t needed and
could burn out the ESC and motors,
not to mention cause a CG balance
If you’ve read any of my previous
reviews about electric-powered models,
I’m all about using arming switches
to protect my fingers! There are no
provisions for an arming switch in
the Twinstar; however, if you use the
power setup I used in this review model
47 Model Aviation MAY 2016