72 MODEL AVIATION
The Blade CX can get
up in a hurry with a little
throttle. A Sport Aviator video shows the CX
bouncing off a cafeteria ceiling. There was no damage and the CX kept whirling.
12-volt power source to operate. (New
systems come with an AC adapter as
well.) You can purchase a 120-volt
adapter separately for $20. Since the
Blade CX is primarily an indoor
aircraft, the adapter makes
sense.
The charger’s 500 mA
output is approximately
0.625C; “C” is the battery’s
800 mAh capacity. This is a
safe current that balances
the pilot’s need for fast
recharging with the real need
to charge safely and prolong
battery life. From what I have
been told, the lower the charge
rate, the more charge cycles a Li-
Poly battery will endure.
The charger is a “balanced” system. To
avoid overcharging one cell, the charger
measures each cell’s voltage individually
while charging and applies a small energy
drain on the “high” cell to keep its voltage
stable until the other cell catches up with
it.
Still, always remove the battery from
the helicopter to charge and do so only on
a nonflammable surface.
A pair of brushed 180-series motors
turns the rotors. The Blade CX will lift off
using only approximately 50% throttle and
is fairly fast when you get it going. (More
about this later.)
BY FRANK GRANELLI
Swash Plate: E-flite Blade CX
Except for eight AA dry-cell batteries and a 12-volt battery source for the charger,
everything needed for flight is in the box. Excellent instructions and a CD ease the fixed-torotary
wing transition.
I HAVE BEEN flying RC for 36 years but
never had much of an opportunity to fly an
RC helicopter. Maybe that is why I can’t
fly an RC helicopter. My flight simulator
proves this every time I try.
Until E-flite’s Blade CX arrived, I had
more CL Stunt (Precision Aerobatics) time
(three minutes on Bob Hunt’s World
Championships airplane and four minutes
at the Texas AMA Grand Event) than I had
successful helicopter time. The Blade
changed all that.
Twin-rotor helicopters have become
popular among RC fixed-wing stick mixers
because almost any experienced RC pilot
can safely fly one of these models and
have fun doing it. If you normally use your
left hand (Mode 2) for more than an
occasional throttle change, you are ready
for the Blade CX to open up the world of
rotary flight to you.
The twin main rotors eliminate the
complexity and extra piloting/trimming
skills involved with using a tail rotor. They
rotate in opposite directions to compensate
for torque and help stabilize the machine in
flight.
However, the Blade CX also has a
complete onboard gyro system for added
stability. With both systems operating it
will hover, rotate, change height, and even
fly forward with just a novice such as
myself at the controls.
Blade CX System: Inside E-flite’s
attractive Blade CX box (which is also a
carrying case) is everything necessary to
get the machine into the air. The helicopter
arrives fully assembled and tested by the
factory. Except for charging the battery, it
is completely trimmed and ready for flight.
Onboard power is supplied by an E-flite
7.4-volt, 800 mAh Li-Poly battery. The
transmitter uses eight AA dry cells.
The onboard battery’s charger needs a
A helicopter
for the masses
05sig3.QXD 3/23/07 10:54 AM Page 72
May 2007 73
Above: The battery is held in place
against a small plastic former by a piece
of hook-and-loop tape. Make sure the
battery wires are toward the open side
of the former.
Right: The heart of the CX is the
combination four-channel receiver, gyro,
and mixing ESC shown. The receiver is
on Channel 21; no toylike CB
frequencies for the CX!
A short vertical distance between the rotor blades and the
“wavy” turbulators enhance the CX’s forward-flight capability.
The supplied 500 mAh balance charger is powered by a 12-volt
resource such as an automotive battery or similar. A wall-outlet
type 120-volt AC adapter is available.
Photos by the author except as noted
Yaw control is achieved by turning the motors at different
speeds while the servos adjust the lower blade’s pitch and angle to
control the remaining directions. Throttle controls climb.
Horizon Hobby offers a motor heat-sink option to provide
extra cooling in case the pilot wants to make a flight, change the
batteries, and then fly again immediately. Running cooler in
electric flight usually translates into a longer operational lifetime.
At $4 for the heat sink and $2 for the adhesive, the improved
cooling system is a great buy. Complete installation instructions
are supplied in the instruction book.
Other options include extra batteries and a “trainer” landing
gear that helps prevent blade-damaging “tipovers” that occur if the
helicopter is landed while moving sideways. Complete
Type: RTF micro helicopter
Main rotor diameter: Coaxial, 13.60 inches
Length: 15.75 inches
Height: 7.17 inches
Ready-to-fly weight: 8.0 ounces
Motors: Dual 180 brushed
Radio: Four-channel 72 MHz FM, E-flite S75 servos, 4-in-1
control unit
Battery: 7.4-volt, 800 mAh Li-Poly with balance connector
Flight duration: 10-15 minutes
Bonus: Now
includes AC adapter
and eight AA
batteries
New, lower price:
$169.99
Specifications
+
• No installation or assembly required.
• Li-Poly charger is balance wired.
• Coaxial, counter-rotating blade rotorhead
design provides incredible stability. -• Too light to fly in any wind.
Pluses and Minuses
05sig3.QXD 3/23/07 11:27 AM Page 73
replacement parts are also available.
The four-channel E-flite FM receiver
(item ELFH1025) is housed in the
“pilot’s” compartment. The unit is a
combination receiver, motor-control
mixer, ESC, and a piezo gyroscope to help
keep the helicopter pointed in the right
direction. This is a remarkable piece of
equipment that is slightly more than 1
inch long and weighs less than 2 ounces.
Two high-speed, high-torque E-flite
S75 servos (item EFLRS75) are installed
at the factory. They weigh only 7.5 grams
each, move 60° in 0.12 second, and are
most commonly used in micro aircraft
such as the Mini Funtana. They provide
quick response and plenty of muscle to
move the lower rotor-blade controls.
The 36-page instruction book is
excellent. It provides all the information
you need to get your Blade airborne safely
and has sections covering fine-tuning the
trims, complete flying instructions, and
maintenance information.
There is an instructional CD, but it can
be difficult for some computers to run. If
you have difficulty, go to MA’s Sport
Aviator online magazine (www.masport
aviator.com) for complete details on
opening this disc.
The CD strongly recommends flying
the Blade CX indoors only, but it does
claim that outdoor flight in calm winds are
possible. I have flown the model in winds
of 2-4 mph with no problems. I think that
is because it flies forward at more than 4
mph with no handling problems. I would
guess that the helicopter has a top speed in
the 10-12 mph range.
There are two reasons for this unusual
forward-flight capability. First, the main
blades are located fairly close to each
other, reducing the leverage the
uncontrolled top rotor can apply to the
fuselage.
Second, each blade has “turbulators”
running the length of the LE that prevent
the composite, damage-resistant rotors
from gaining too much lift during forward
flight. As a result, the helicopter remains
fully controllable and responsive during
forward or reverse “high-speed” flight.
First Flights: I will admit to some
nervousness as I readied the Blade CX for
its maiden flight. My first attempt with a
helicopter was to be in a confined school
cafeteria. My club—the Roxbury Area
Model Airplane Club (RAMAC)—meets
in this cafeteria.
I had planned to use the school gym,
but there were three basketball games
scheduled for that night. I couldn’t
convince the teams to play in the cafeteria
and let me use the gym in which to fly!
The onboard battery slides into the
fuselage bottom. Make sure the wire
connector is on the side with the cutout. A
Blade CX2
An RTF micro electricpowered
helicopter with
spread spectrum control
The Blade CX2 is the original
beginner-friendly Blade CX with
the added benefit of Spektrum
2.4 GHz DSM (Digital Spectrum
Modulation) radio control. Fly
the Blade CX2 anytime, without
ever having to worry about
interference.
In addition, the 4-in-1 control
unit has been updated with
improved gyro and tail control,
which gives the Blade CX2 even
better tail response while
minimizing drift. The CX’s all-up
weight has been reduced
because the new CX2 includes
two feather-light Super Sub-
Micro S60 servos instead of the slightly larger S75 servos.
As is the original Blade CX, the CX2 is ready to fly right out of
the box; that is, after the 7.4-volt, 800 mAh Li-Poly battery pack has
been charged. The 2.4 GHz DSM five-channel transmitter requires
only four AA batteries, and even those are included.
The CX2’s flight performance is initially limited, but it’s perfectly
suitable for the student pilot who has no RC experience
whatsoever. The 4-in-1 unit has adjustment controls that the
aspiring pilot might want to fine-tune after flying the helicopter for
a while.
The instruction manual is great at describing these adjustments’
functions. After making the changes, the controller must be reset
for the modifications to take effect.
Our sample CX2 needed the gain reduced to take the bounce
out of the “tail-rotor” control. To further trim the model, we
adjusted the mixing to the point where the tail-rotor trim could be
kept in the center.
There was no need to adjust for right and left on the cyclic
controls (that’s the elevator and aileron to you airplane pilots).
However, for pitch approximately a half turn on the ball link took
out the up-trim needed to make the CX2 hover hands off.
To hop-up the Blade CX’s performance some owners move the
control linkage from the inside hole of the servo output arm out to
the second and third hole. This change makes the CX more agile
and easier to keep in forward
flight because it has more
control-surface movement.
Other upgrades to the CX
and CX2 include a line of CNC
aluminum mechanics. If a part is
ever broken, you might consider
using the metal upgrade instead
of the plastic replacement. MA
—Michael Ramsey
[email protected]
74 MODEL AVIATION
William Ramsey gains confidence as a
new helicopter pilot. Jenna Helms
patiently waits her turn. Michael Ramsey
photo.
The Blade CX2 is a great tool for learning
the basics of piloting an RC helicopter. Its
inherent stability makes hovering nose-in
much easier. Ramsey photo.
05sig3.QXD 3/23/07 10:58 AM Page 74
May 2007 75
Length: 16.42 inches
Height: 7.17 inches
Main rotor diameter: 13.6 inches
Weight with battery: 8.0 ounces
Main motor (two): 180 brushed
(installed)
Battery: 7.4-volt, 800 mAh Li-Poly
(included)
Charger: DC Li-Poly balance charger
and AC adapter (included)
Transmitter: 2.4 GHz DSM five-channel
(included)
Onboard electronics: 4-in-1
receiver/mixer/ESC/gyro (installed)
Servos (two): Super Sub-Micro S60
(installed)
Street price: $189.99
Blade CX2 Specifications
piece of hook-and-loop tape holds the
battery in place.
Place the helicopter on a flat, level
surface. Connect the battery but hold the
Blade CX motionless for four seconds. The
gyro is aligning during this stationary
period. A flashing red LED changes to
steady green when the alignment process is
complete and the helicopter is ready for
flight.
With RAMAC members present—
except Frank Costello, who had to stay in
the open taking photographs, prudently
hiding behind vending machines, or
escaping out the twin doors—I gave the
Blade CX a bit of throttle. The rotors began
to spin and the helicopter lifted roughly 6
inches.
The model’s height remained stable, but
there was some left drift and the nose
wanted to swing to the left. After four
clicks of right “aileron” trim and holding
the “rudder” stick slightly to the right, I was
hovering a helicopter.
From the first seconds of flight I had no
trouble flying this aircraft. That is no
exaggeration. With more than a dozen
witnesses, it can’t be.
I am not claiming that I flew the Blade
CX to its full potential throughout those
first flights, but I could hover it and move it
slowly in all four directions. During the
second flight I landed the model on nearby
tabletops. By the third flight I was flying it
around the room. Each flight lasted
approximately 10 minutes.
I later learned that twin-rotor helicopters
tend to change “rudder” trim as the motors
heat up. Drifting is typical with electronic
gyros, and the Blade CX was no exception.
The nose swung left at takeoff,
requiring right rudder, but after a few
minutes I needed full left trim to prevent a
rightward swing. Near the flight’s end I
was holding slight left rudder along with
the left trim. It is possible that the motor
cooling fins will minimize this trim effect,
but I have not tried them yet.
I now have approximately 45 flights,
indoors and out, on the Blade CX. I can
hover and land it anywhere within reason.
The model will fly tight circles, good
figure eights, “spin” easily in place, and is
nearly impossible to mistreat. I have
learned many piloting lessons from this
aircraft that will let me move to a singlerotor
helicopter such as E-flite’s Blade
CP—the next step up the helicopter ladder.
At this point I don’t even think about
holding “rudder” input. The Blade CX has
trained my left hand to move on its own
accord without conscious input. I have
learned to fly the nose, not the tail, for
proper yaw control. I have learned that if
you can feel the transmitter sticks moving
at all, you are applying too much control
input.
But most of all I have learned that
helicopter flying is more fun than I could
have imagined. Better yet, I can actually
do it.
There are five videos of the Blade CX
on the Sport Aviator Web site. Three are of
my hesitant first flights and two are of a
real RC helicopter pilot—Dean
DiGiorgio—putting the model through its
paces.
If you have ever wondered about
helicopter flying, this inexpensive machine
can open a new world of RC piloting to
you. Look at the videos and decide for
yourself. MA
Frank Granelli
[email protected]
Distributor:
Horizon Hobby, Inc.
4105 Fieldstone Rd.
Champaign IL 61822
(877) 504-0233
www.e-fliterc.com
Our Full-Size Plans List has hundreds of models from
which to choose. See page 199 for details.
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