The Rare Bear requires a battery that can comfortably output more than
60 amps. I used the recommended E-flite 4S 3,300 mAh battery with a
50C discharge rating.
The radio compartment is simple and uncluttered with
factory-installed servos and a receiver.
precaution. Accidental propeller spin-ups in my workshop
are no fun. The propeller required balancing anyway, so the
removal effort was definitely worthwhile.
The manual provides control throws for launching/landing
(high rate) and normal flight (low rate). I was surprised by the
small travel values suggested for the elevator (3mm and 5mm).
It didn’t look adequate for a model of this size. Resist the urge
to add more throw. My flight testing has proven the suggested
values to be adequate.
The AR636A receiver has built-in AS3X stabilization.
Although AS3X won’t level the wings or save you from a
crash, it makes the airplane fly smoother. The intent of AS3X
stabilization is to minimize the effects of outside forces on the
airplane’s flight path.
Power for the Rare Bear comes from a 1,200 Kv outrunner
motor spinning an 8 x 8 propeller. The motor is controlled
by a 70-amp ESC, which also includes a BEC system to
power the radio components. This system’s static amp draw
is nearly 62 amps, so you must choose a battery that is
capable of delivering that amount of current. I used E-flite’s
recommended 4S 3,300 mAh battery with 50C discharge
capability (part EFLB33004S50).
A plastic tray integrated in the airframe serves as the battery
mount. The battery is secured using a combination of self-adhesive hook-and-loop tape and hook-and-loop straps. I
positioned the battery on the mount to achieve the suggested
center of gravity location without adding any ballast.
My power system measurements indicated that the aircraft
produces more than 950 watts for this 2.8-pound airplane.
That equates to a power loading of more than 300 watts per
pound. Most sport models do well at approximately 100
watts/pound. Although I’d previously flown numerous high-performance models, none had a power loading this high. I
wasn’t sure what to expect, but there was no doubt that it
would be exciting!
Flying the Rare Bear
The flight-ready Rare Bear can be easily disassembled to fit
back into its box. This feature came in handy when I decided
to bring the model along on a family trip to Florida. My
initial flights were made at the Flagler Radio Aero Modelers
RC Club field in Bunnell. I appreciate
the hospitality and support of the club
members during my visit.
Because the Rare Bear has no landing
gear, it must be hand launched. A hand
grip is molded into the bottom of the
fuselage to make this task easier. Despite
all of the power on tap, this airplane
requires a good, strong throw into the
wind. Anything less will result in a belly
flop back onto the ground.
All of my launches so far have relied
on someone else to throw the airplane. I
doubt that I will ever deviate from that
trend. Having a measurable headwind
significantly eases the burden on the
launcher, but launching the model is
never a casual event.
After the Rare Bear has
reached flying speed, it
becomes a more manageable
airplane. It is predictable and
easy to control—even if it is
humming along briskly. The
bright color scheme is easy to
see and in-flight orientation
has not been a problem for
The stated goal of the Rare
Bear is speed and it definitely
delivers. During one of my
flights, someone remarked how fast and smooth the model
was. He was surprised to learn that I was flying at only half
throttle! Does the model hit the 100-plus mph speeds claimed
by E-flite? I don’t know … I haven’t measured it, but I have
no reason to doubt it. This stubby little chunk of foam can
The Rare Bear does not get jittery or overly sensitive when
flying at high speeds. Control response seems consistent
throughout its normal speed range. The only difference that
I’ve noticed so far is a tendency to wag its tail when carving
through turns at high speeds. I can’t detect this behavior at
I don’t know how much the AS3X system influences the
RB3 Model Aviation DECEMBER 2015