Type: Semiscale ARF
Skill level: Intermediate builder;
Wingspan: 50 inches
Wing area: 500 square inches
Length: 44. 25 inches
Flying weight: 4. 25-4. 75 pounds
TES T-MODEL DE TAILS
Motor: Great Planes RimFire . 32
brushless motor; APC 13 x 8E
controller: Castle Creations Ice 100 ESC
Battery: FlightPower 4S 3,350 mAh
Radio system: Futaba 7C 2. 4 GHz
transmitter; Futaba R617FS
receiver; four Futaba S3150
mini digital servos
Flying weight: 4. 6 pounds
Wing loading: 21. 2 ounces per square foot
Flight duration: 8 minutes
• Snazzy looks!
• Huge access hatch.
• Aggressive flight performance.
• Oversize tail wheel assembly.
AT A GLANCE ...
A Flight Power 4S 3,350 mAh battery fits comfortably within the XA41’s
battery area and is easily reached with the access hatch removed.
cockpit when the XA41 is in the pits.
The firewall could be located in a range of positions to
accommodate different motor lengths. I used an ElectriFly
RimFire . 32 motor, which was a perfect fit with the firewall
fully forward, and 1/4-inch spacers behind the motor mount.
To mate the motor to the firewall, I slightly elongated the slots
intended for the included blind nuts.
The provided nylon spinner works well, although I had to
slightly enlarge the propeller openings to fit the APC 13 x 8E
propeller. Be aware that overtightening its screws will warp the
spinner backplate and cause it to wobble.
I mounted a Castle Creations ICE- 100 ESC as far forward as
I could on the motor mount. The ICE- 100 is overkill in terms
of power requirements, but it was handy and its extra mass was
useful in the nose. The power system’s final component was a
FlightPower 4S 3,350 LiPo battery. This setup provides nearly
800 watts of power at the altitude where I fly ( 3,200 feet).
I set up the control throws on my Futaba 7C transmitter
per the manual’s suggestion. The completed airplane weighed
71. 6 ounces ready to fly, before adding 2 ounces of weight in
the nose. This provided manageable wing loading and power-loading values.
at 3. 4 inches
behind the LE.
This is within
range, so that’s
how it was first
flown. The aircraft
was flyable, but
the ailerons and
After a few
flights, I added 2
ounces of lead to
the forward inner
lip of the cowling.
This moved the
CG forward by
. 3 inches and
made the Sbach
values in the
section reflect this
outings, the XA41
has been steady.
With the tall tail
wheel, the airplane is nearly horizontal when sitting on the
landing gear. Subsequently, P-Factor is small and little rudder
correction is required for a straight takeoff roll. With the
RimFire . 32 setup, the airplane quickly accelerates and has
great climb performance. Do you like to go vertical right after
takeoff? If so, go ahead.
Most of my aerobats are fairly draggy and favor moderate
speeds. The XA41, however, doesn’t seem to mind stretching
its legs at full gallop. A low-altitude, high-speed pass is a good
way to break up a series of aerobatic moves.
The suggested control throws are good starting points.
Full-deflection rolls, even on low rates, are quick. I ended up
setting the aileron high-rate throws to the suggested low-rate
value. I then set low rates to achieve a comfortable roll rate for
slow rolls and rolling circles.
Elevator response is good for most of the speed range. I
slightly increased the high-rate values to get increased pitch
authority at low speeds. This has the ancillary effect of
permitting spine-crunching snap maneuvers. It’s a wonder
63 Model Aviation MAY 2014