Electrics - 2006/12

SANTA’S BIG Bag o’ Goodies: This being the holidays, it
seemed fitting to go through some of the things I’ve seen, bought,
and lined up for reviews. The amazing amount of new electricflight
items is mind-boggling, and with the Northeast Electric
Aircraft Technology Fair about to take place as I write this, I know
I’ll see even more products I can’t resist.
Model Electronics Corporation MiniBox and MiniBox Plus:
Quality gearboxes for smaller motors have always been a rare
commodity. Model Electronics Corporation (MEC) has introduced
small gearboxes that join the other two (SuperBox and
MonsterBox) in the MEC hangar.
The new MiniBoxes have been designed to fit many small
brushless motors, with mounting holes spaced at 5/8 inch (16mm)
and 3/4 inch (20mm) on centers. MEC solved the mounting
problem by creating those two sizes of front and back gearbox
plates. All other MiniBox parts are interchangeable.
If you have crash damage to the gearbox, it can easily be
repaired, and that is preferable to bending a motor shaft. You can
do a complete rebuild on the MiniBox in a few minutes at the field,
providing you put a few spare parts in your field box.
Each front plate has three identically spaced threaded holes,
allowing the MiniBox to act as a motor mount by being fastened to
a “Bulkhead” (screws included). A stick motor-mounting assembly
is available for those models designed to use them. The female part
of the mount accepts the standard 10mm x 10mm square beam.
This is a neat gearbox, and you can put it on an outrunner if you
happen to have one that spins too high of an rpm for your
application. This will also help protect your motor shaft for those
3-D maneuvers that go bad.
Super Airplanes and Gear: I’ve talked with Jerry Orme of Vision
Hobbies several times and had the pleasure of getting to know him
and his staff at the Southeast Electric Flight Festival this year.
They sell an incredible variety of the new PJS motors and
everything you need to get a system in your model.
And if you don’t have a model, you need to talk to them about
that too; they have some great ones. A photo shows one that
wowed the crowd this year.
The converted Great Planes Ultimate 160 had one of Jerry’s
PJS 10000 motors spinning a carbon-fiber 22 x 12 propeller. With
a 10S 7400 mAh pack and 95 amps at full throttle, the performance
was unlimited. This thing tore up the sky and spent as much time
low and inverted as it did upright; it was absolutely incredible!
Jerry also brought a V-tail airplane of the company’s own
design called a Sweep Vee. This ARF is a joy to fly powered by a
PJS 3D 2500 brushless outrunner motor, Mototron 36-amp ESC,
and Poly RC 3700 4S pack.
At 5 pounds, I thought the Sweep Vee felt just like an RC
Aerobatics model when I flew it. This airplane was true, with no
bad habits. I didn’t want to give Jerry the sticks back after I flew
it.
Must-Have Electronics: Some of us enjoy gathering as much
information about our systems as possible, and others just want to
know enough to keep their gear in good shape. Whichever group
you fall into, you’ll be glad you bought the following two devices.
The LiPoDapter+ is from SLK Electronics (the same company
that brought you the indispensable ElectriCalc). This little $40
gem allows you to safely charge your Li-Polys and the new M1
cells with your regular Ni-Cd/NiMH charger, such as the Astro
110 or 112 series.
The new unit can charge as many as 10 M1 or eight Li-Poly
cells. It can handle up to 8 amps to charge 8 Ah Li-Poly packs in
an hour or M1 packs in less than 20 minutes. This is limited by
your Ni-Cd charger’s current and voltage capability. The
LiPoDapter+ is a definite must-have for those of us with a great
deal of money tied up in the older chargers.
Greg begins compiling his holiday shopping list
Electrics Greg Gimlick | [email protected]
Also included in this column:
• Quality gearboxes from
Model Electronics
Corporation
• PJS motors from Vision
Hobbies
• “Must-have” electronic
goodies
• Electric helicopter news
MEC’s MiniBox and MiniBox Plus cover the park flyer market.
The key to the strength is quality machining and Delrin spur gear.
Vision Hobbies produces big power with its PJS motors. The Ultimate 160 has a PJS
3D 10000 brushless outrunner. For 30 cells or 10S Li-Poly, Kv = 212, recommended
propellers 22 x 12-24 x 10.
120 MODEL AVIATION
12sig4.QXD 10/25/06 11:42 AM Page 120December 2006 121
The new DPR-100 Digital Power
Recorder is from BNB Products. As you
might have gathered by now, I like data
loggers so I can see what my setups are
doing. For years we guessed by doing math
and measuring everything before and after
a flight, but now we can see it before,
after, and during the flight. This can be a
real eye-opener.
I recently tested a setup in a Giant Scale
airplane that measured 90 amps full
throttle static, but in the air I found that
most of the flight was spent between 35
and 45 amps. This is great info to know.
My DPR-100 will handle up to 30 volts
and 100 amps, although there is a way to
make it handle higher voltage if you need
to by using two packs in series and wiring
the logger into one side. This will read the
total current and half the voltage, but the
software can be set to compensate for this
to show the actual voltage when it graphs
the data.
This data logger comes with all the
software and USB cable to hook it to your
computer. The buffer will handle up to nine
hours at the lowest sampling rate, but the
default rate of four per second gives you 40
minutes of data logging four parameters. This is great, and you can
keep logging flights without downloading the data until it’s full.
The graph will show all of them together or you can select which
one to display or save.
One great thing I learned was that this can be plugged in
between the battery you’re charging and the charger to record and
graph the charge cycle. Suddenly your inexpensive charger does
things that chargers costing four or five times as much do. If
you’re an info freak, you can keep data for all your packs and see
if they’re beginning to decline.
Greg’s venerable Lite Machines Corona is a workhorse and a lot
of helicopter for the price—especially if you do what he did to
the tailboom.
Helicopter Hobbies’ Quick EP-8. Incredible workmanship in this
fully CNC-machined kit. A lot of quality for less than $300.
DPR-100 data gathered during a 12-minute flight on Greg’s LT-25. Great info there on
maximum, minimum, and average voltage; current; and two temperature probes.
Must-have electronics in Greg’s shop. LiPoDapter+ (L) lets him use
Astro 112 charger for Li-Polys and M1 cells. DPR-100 data logger (R)
lets him graph data during flight and while charging batteries.
12sig4.QXD 10/25/06 11:55 AM Page 121rpm sensors for mine, but in the photo of
the graph you’ll see that I didn’t use the
rpm sensor on this flight. This is installed
in my LT-25 using a MaxCim system on a
6S pack of A123 cells (the new M1 cells).
The red line is the motor temperature
and the yellow line is the battery
temperature. The blue line is the current
and the green is the voltage. You can see
that there were a lot of aerobatics in this
12-minute flight, and the voltage was
steady throughout. The battery and motor
temperature only got up to roughly 107°
on a balmy southern afternoon when it
was 92° outside.
The DPR-100 data logger installs in
seconds and is a definite must-have if you
want to know what’s going on during your
flight or charge cycles—and it costs less
than $85.
More Electric Helicopters: In the last
column I mentioned that I’d be building
the Quick QJ-18 from Helicopter Hobbies.
After talking to Harold Little, who is the
brains behind the operation, I decided to
do the Quick EP-8. It is a bit smaller than
the 18 and is more economical to support,
with a smaller motor, fewer cells, etc.
As you can see in the photo, this is a
high-quality CNC-machined kit. By the
time you read this I will have flown it, but
for now it’s in the final stages of
assembly. So far it has gone together like
a dream. My EP-8 will be powered by the
Hacker 10XL and the 6S packs of Hecell
Li-Polys shown. All the components
you’ll need are available directly from
Harold, so getting everything right is
simple.
In the world of ARFs it can be
intimidating to see all the parts that come
in a kit, but I can assure you that it’s fun
to assemble something as finely machined
as this. I’ll have more info when I
complete it.
A photo shows my Lite Machines
Corona 120. It is powered by an Astro 020
motor made for helicopters and a Phoenix-
35 controller.
This is the newest version of the
Corona and features the aluminum crutch
so you no longer have to glue up a
plywood crutch. It’s an economical way to
try out a “real” helicopter because it’s a
fixed-pitch version and tough as nails. The
control linkages are much less
complicated than most, but they are
effective and serviceable.
The tailboom had a less than perfect
arrival. I just balled it up in the yard and
thought I had destroyed it. When I picked
it up I was shocked to see how the main
rotor blades folded up and back without
breaking anything. They struck the
tailboom.
After taking a good look at it, I decided
I’d see if I could just bend it straight. With
some careful application of brute force I
got it straight and nothing seemed to be
binding. The dents are still there, but it
flies as well as it did before I crashed it.
How’s that for cheap helicopter training?
A regular helicopter would have cost
almost as much as this kit just to repair.
I’m impressed with the Corona as a
trainer. You won’t do 3-D with it, and
being fixed pitch it can be a bit more
challenging to maintain constant altitude,
but you won’t find more bang for the buck
in the helicopter market.
I want to thank Jim Ryan for building my
Corona for me while I was backed up on
some other projects. He makes it possible for
me to keep up with this business.
Final Approach: That’s it; I’m out of
space for the month and year. I hope your
holidays are great and your new year is
exciting. See you at the field! MA