RADIO CONTROL AEROBATICS - 2003/06

June 2003 85
THE QUESTION OF having product reviews in this column
came to me recently in an E-mail. I am always interested in what
you all would like to see in this column. A product review is
popular with most readers. It requires a different approach, such as
taking photographs of the building process as you complete the
model. In this column it is not viable to do justice to a product or
products and still have any room left.
My basic plan is to review how a well an airplane flies the
current AMA Pattern schedules. What was brought to my attention
was the need to include much more detail when writing about a
particular airplane. I can relate to that because I too like to know
things such as engine information, radio and servos used, etc., so
thank you for the request and I’ll endeavor to provide as much
detail as I can in the future.
Product News: The O.S. 1.60 FX will soon have a competitor,
which is being produced by Webra and imported by Horizon
Hobby. The Webra 1.60 will have a rear exhaust, an integral
pump, and be close in weight to the current 1.45. This should give
a welcome boost to the vertical performance needs of the newer
wide-body airplanes.
Piedmont Models has been busy working on a second version
of its popular (and sold-out) Focus. Although the Focus II is
similar in appearance to the original Focus (several parts are plugcompatible),
there were enough changes to require a redesign from
the ground up. The fin and rudder are taller and wider. Now there
is a welcome top access via a removable canopy. Less obvious is a
new and different internal structure.
During the lunch breaks at last year’s Tournament of
Champions, the Hacker team gave several demonstrations of
electric-powered airplanes that were fully Pattern-capable. Just as
the auto industry is expanding its interests into the field of electric
people movers, one day Electrics may be all that we fly. If that is
the case, the future does not look that bad.
The pesky white stuff that keeps falling from the sky has
prevented the testing of a slightly modified Diablo. The Diablo is
one of a family of electric airplanes imported by Esprit Model of
Eric Henderson, 303 Shady Ln., Marlton NJ 08053; E-mail: [email protected]
RADIO CONTROL AEROBATICS
Electric Pattern models may be the wave of the future. Esprit
Diablo was modified from 3-D to Pattern configuration.
Canopy was doubled for more Pattern-current design.
Wing-dowel antirotation pin was replaced by Gator wing
adjusters. This allows fine-tuning during flight testing.
The Hacker motor and the huge air duct direct to electric “fuel
cell,” a.k.a. a 20-cell Ni-Cd or NiMH sub-C pack.
Massachusetts. It is a 3-D, highperformance
model that uses a Hacker B50
9XL brushless motor with 20 sub-C cells
as a power source. Ni-Cd packs will
provide a more immediate dazzle in
performance, but 20 NiMH 3000 mAh
cells will give longer duration. For more
info, E-mail prop.rc@verizon or visit the
Web site at www.espritmodel.com.
So what does it take to get a viable
electric Pattern model in the air? “This is
not your father’s park flyer,” so everything
had to be purchased from scratch. The
people at Esprit Model were helpful, and
the order was placed to basically equal the
owner’s model. (This airplane has a
fiberglass fuselage, hence the FG
designation.)
• Diablo Top FG: $289
• Hacker B50 9XL with 5.2:1 gearbox: $309
• Hacker Master 99-3P Opto speed
controller: $239
• Ultimate Battery Eliminator Circuit
(BEC): $30
• Battery pack—20 cells Ni-Cd: $115
• Motor mount: $25.25
• Heat sink: $19
All of these new and old JR radios are still Pattern-compatible,
depending on your needs.
There is a whole range of functionality between these two radios.
How much of it do you really need?
June 2003 87
June 2003 89
• Deans gold connectors: $3
• Spinner 42/6mm: $25
• Prop APC-E 16 x 10: $16
The airplane was modified slightly.
Who can build an Almost Ready to Fly
these days without making some changes?
In this case the big change was to convert
the canopy and battery hatch into a onepiece
top deck. A longer and much larger
replacement Focus canopy was used over
a frame that was twice the size of the
original opening.
The idea was to move the center of
fuselage lift farther forward. The spin-off
was much easier access to the battery and
radio compartment. The wing is in halves
and uses a wing tube with one antirotation
pin at the rear of each wing. This pin was
replaced with a Gator wing adjuster for
fine flight tuning.
The Hacker brushless motor is a beast!
In this model it is turning a 16 x 10 APC
electric propeller. Once the motor was
installed, a test of the speed controller
produced an air blast in the workshop that
blew most of the tools off the workbench.
Very promising indeed!
Those of you with Web capabilities can
see a demo-flight video clip of the Diablo
in standard configuration on the Esprit
Model Web site. Unfortunately I don’t
have the test data on my model yet
because of bad weather.
The model has a 61-inch wingspan and
a length of 65 inches. It has fixed gear, so
it could be flown on a four-channel radio
with a Y lead to the two ailerons. This
airplane was configured on a JR PCM
10SXII with a 950 PCM receiver and four
JR DS4321 digital servos. These little
servos think they are full-size and will
handle an electric model of this size.
A BEC was spliced into the speedcontroller
feed to provide the
servo/receiver power. The all-up weight,
including battery, came out at 9 pounds,
1⁄2 ounce. This might seem slightly heavy,
but bear in mind that the 16 ounces of
glow fuel will not be added to this
airplane for flying purposes.
A high-end computer radio was used
because the Diablo was set up with three
different flight modes; one with minimum
throws for smooth Pattern flying, one with
sport throws for fun, and one with extreme
3-D throws for that crazy stuff done in
artistic aerobatics.
The choice of radio leads into this
month’s Frequently-Asked Question: What
kind of radio is best for Pattern flying—in
particular, transmitter, servos, PCM
[Pulse Code Modulation] receivers, mixes,
etc.?
This is a big question, and to answer it,
it is probably impossible not to step on
someone’s toes. The answer is broken
down into what you need, what is nice to
have, and the probably more contentious
what I like to have.
To illustrate the answer, there is a
picture of a range of new and not-so-new
JR radios that could fly a Pattern airplane.
I chose the JR range because I have them
to photograph and I go back as far as the
Unlimited 8, circa 1978. (I have such a
degree of familiarity with these radios that
I can almost “program” all of them
without a manual.)
To begin the answer, it is important to
accept that human nature will gravitate to
the more expensive and exotic toys that
we can buy. Having the best/latest/most
expensive equipment can even promote
unwelcome elitism. Sometimes it will help
you to have a “better” radio, but—and it is
a big but—only when you are ready for it.
I don’t think there is a radio in the world
that can make a model fly better, but some
make a model easier to set up and easier to
fly.
So what do you have to have? A
Pattern model can be flown with a fourchannel
radio: one for ailerons (a Y lead
can be employed if two servos are used),
one for throttle, one for elevator, one for
rudder, and a fifth is required if a
retractable undercarriage is used. If your
radio has the preceding, don’t go out and
buy a new one just to fly Pattern.
Most radios these days are some form
of computer radio and allow for the
ailerons to be fitted into a channel each. A
low-end radio such as the JR 642 (there
are more recent equivalents) has all of the
functions you need and a few more.
Once you get past the basic needs, you
get into what is nice to have. The ability to
set the endpoints of servo throws is handy
once the base level of mechanical settings
has been made. All of the modern radios
have dual rates and exponential for flight
tuning.
In JR terms, the 388, the 8103, the
newer 374 and old 347, the top-of-the-line
10SXII, and the most recent 10X do the
basics, so why would you want more? It
comes back to the ease with which you
can change things to suit your needs and
improve the airplane in the air.
Then you get into what you must have
in a radio. I find throttle-curve
adjustments most useful so that I can set
the power to where I want it on the throttle
stick.
A big feature is the ability to program
in the correct amount of elevator and
aileron correction in knife-edge flight. The
high-end radios have this as a listed
function. It can be done with a JR 8103,
but it takes some free-mix programming.
When a model pulls to the canopy in a
down-line, a neat trick is to mix a tiny
percentage of down-trim at low throttle.
There are some advantages to the
higher-end radios, but just fly with what
you know well and practice the schedules
until you need the features. You’ll know
when you need to upgrade; it will be the
aforementioned human desire or that you
are simply ready for more features!
One feature that is an absolute must for
me is PCM because it allows you to
program the default settings of the
airplane if you get radio interference, lose
a crystal, etc. in the air or on the ground.
Many people confuse previous-position
servo lock with fail-safe programming
options. My standard fail-safe settings are:
throttle to idle, all controls to neutral
except the elevator, which is given
approximately 5° of up. I get a warning in
the air if the throttle cuts back, and a slight
bump in the flight path that tells me it is
time to land!
The retracts, if used, are left in hold.
This is because if the interference is in the
pits and the engine is running, you don’t
want the wheels to retract. Similarly, if the
airplane is in the air, I don’t want the
wheels to come down and rip out the gear
mechanisms in a rough “free-flight”
landing.
Also with PCM you usually get a
receiver-battery-low warning. This is a big
plus that also tells you to land
immediately. All airplanes become
expensive and can be dangerous. PCM
fail-safe can save injury and many forms
of cost.
Technology does change how you do
things. A “fancy” radio gives you
flexibility that you did not have before.
Initially a computer radio can be more
inhibiting because it is new to the user and
can be harder to use at first.
In a similar vein, this column was not
typed this time; it was “talked.” I used
voice-recognition software. It needed to
learn how I speak, and the room had to be
cleared of background noises (kids, etc).
The noise from our heating system didn’t
help either. It took me three times as long
to do the column this way, but now the
computer understands an Anglo-Scottish-
Boston-New Jersey-English accent! My
finger pads don’t hurt, as they usually do,
and the ideas flowed much easier.
So until we “talk” again, keep flying
smooth! MA
90 MODEL AVIATION