122 MODEL AVIATION
Fixing errors that have been published in recent columns
Electrics Greg Gimlick | [email protected]
Also included in this column:
• Greg takes us back to the
basics and gives us an
excellent electric-power
review
Left: The author can spot a hobby shop a
mile away. The Hayes Hobbies people are
hobbyists themselves, and the business
has been family owned for 40 years.
Below: A well-stocked hobby shop, with
many spare parts and kits from various
manufacturers. And you can talk with
someone who knows the merchandise
and can recommend from experience.
FAUX PAS—MEA CULPA: Going
back a couple issues I find that I’ve been
errant in a couple of my statements.
Some of it is my fault and some of the
blame lies elsewhere, but I’d never blame
an editor; after all, they are the bosses.
I referenced John Worth’s E-zine and
Bob Aberle’s article about the indoor fly
at the NEAT (Northeast Electric Aircraft
Technology) Fair that was covered
extensively. I gave the wrong title to the
E-zine, and as a subscriber I knew better.
The title of the publication is RC Micro
World and the address is www.cloud
9rc.com. Subscriptions are available
online for AMA members for $20 a year
and $30 for nonmembers. You had better
join AMA if you haven’t already.
The AstroFlight 120 motor I
unashamedly admit to loving in my big
WACO is a conventional inrunner.
Through some miscommunication
between me and MA it was referred to
incorrectly in one of my columns. It is an
inrunner and an exceptional one! Check it
out at www.astroflight.com.
Where Do We Go From Here? Back to
school! I’m going to step back this month
and address some basic aspects of getting
into Electrics. This is a basic primer, not
intended as the be-all and end-all of
electric flight, but I hope to address some
questions I get on a monthly basis.
We have achieved a plug-and-play
world in Electrics, but you still need to
know where to go, what to buy, and why.
The key is to help you not waste your
money.
As the Electrics master Keith Shaw has
said, “Buy cheap, buy twice.” Don’t
confuse inexpensive with cheap, but be
smart about your purchases and you’ll
thank us for it later.
Where do I learn stuff? The best place to
get started is your local hobby shop. More
and more shops have gotten on the
electric-power bandwagon and have staff
members who are knowledgeable enough
to guide you.
If you’re lucky you have a shop like
Hayes Hobbies (www.hayeshobby.com) in
Fayetteville, North Carolina, which has
been in business for 40 years. I bought my
first gear there, and the employees guided
me around all the pitfalls along the way
starting in the 1970s.
I don’t think twice about making the 90-
mile round trip because this store has
incredible stock and the prices are
competitive with any mail-order house.
Many places have shops such as this, and it
will pay you to search them out.
If you are so far out in the boonies that
there are no local shops, you might want to
get online and go to RCGroups (www.rc
groups.com), the E Zone (www.ezone
mag.com), or RC Universe (www.rcunive
rse.com). These sites either specialize in
electric flight or have forums that do.
Keep in mind that although there are
monitors, you have to read and think things
06sig4.QXD 4/20/07 2:08 PM Page 122
June 2007 123
L-R: Neu 6mm gold bullet, 3mm gold bullet, Deans Ultra, Anderson Powerpole cut
down in size, Anderson Powerpole full size, AstroFlight Zero Loss Connectors. All
excellent choices.
Packs on left are MEC Solderless Power Tubes. Top to bottom: 6S pack of A123 cells,
two packs of NiMH cells. Right, top to bottom: 5S pack of Li-Polys, 3S pack of
A123Racing cells, 3S pack of Hecell Li-Poly cells, NiMH receiver pack from NoBS
batteries on right.
Meters are a must if you’re serious about Electrics. L-R: FMA
Direct combo multimeter/shunt, AstroFlight Super Wattmeter.
Clockwise from top left: TME Xtrema Li-Poly charger, A123
balancing charger, Orbit Pro Ni-Cd/NiMH/Lithium charger, SLK
Electronics LipoDapter, AstroFlight Blinkys, AstroFlight 109 Lithium
charger, AstroFlight 112 Deluxe NiMH/Ni-Cd charger.
through with a grain of salt for clarity and
accuracy. Most of these sites provide
beginners’ sections with great information.
Check with the AMA museum store
about the availability of a CD called the
“R/C Model Aircraft Quick-Start Guide” by
MA Technical Editor Bob Aberle. I think it
costs roughly $3 plus shipping and handling
and is full of useful information.
Where do I buy? Again, I favor the local
hobby shops. If they aren’t available you
can order from many of the commercial
Web sites such as Hobby Lobby, Tower
Hobbies, and Horizon Hobby. Look for
them on the Google search engine and the
addresses will come up.
Talk to techs who know what they are
doing, and if you have a question they
can’t answer call someone else. New
Creations R/C, Radical RC, and Model
Electronics Corporation have staff
members who fly electric and are more
than capable of keeping you out of trouble.
Pick up the phone and call a local
hobby shop, even if it’s out of town, and
check on what it can do for you. I call
Hayes Hobbies all the time and order stuff
over the phone.
Basic Tools: Nobody should get into
Electrics without some basic tools,
including soldering irons (not soldering
guns), a meter of some sort, connectors,
wire, solder, batteries, and a charger. There
are not too many items, but they are
important.
Another tool I highly recommend is one
of the electric-flight-prediction software
programs such as MotoCalc (www.moto
calc.com) or ElectriCalc (www.slkele
ctronics.com/ecalc). These inexpensive
products will save you more money and
aggravation than you can imagine.
06sig4.QXD 4/20/07 2:32 PM Page 123
They have tutorial/help sections that are
worth way more than the cost of the
programs. I use them when readers write to
me and ask for projections because they do
all the math and contain more information in
their databases of motors and batteries than I
could ever hope to assemble. Take my word
for it; you will not regret spending the $40.
Meters: You will need some sort of meter if
you don’t want to burn up your gear. You
may get away without one initially if you
follow a knowledgeable mentor’s advice
about what equipment you need for your
particular model, but you will need one
sooner or later. The two shown are perfect
for the job and won’t break the bank.
The AstroFlight Wattmeter plugs in
between the battery and the speed control
and will indicate volts, amps, watts, and
amp-hours. It’s simple and gives you all the
basic information you need to know when
adjusting propeller sizes, etc.
The FMA Direct (www.fmadirect.com)
multimeter/shunt combo is another great tool
you won’t regret owning. It serves a dual
purpose of giving you a multimeter and a
shunt to allow you to read current levels well
above the usual limits of the meter.
The reason why it’s so important to know
the voltage and current your system draws is
to keep you from needlessly burning
something up. If there is a problem, you can
diagnose it properly, and if you ask for help
the person on the other end of the phone or
E-mail will want to know how many volts
and amps you were pulling.
Batteries: This area is changing as quickly
as the electric-power world itself.
Advancements are coming at a pace I’ve
never seen, and each cell type has its own
purpose and attributes. The type of cell you
choose will depend on the application, and
the dealer can steer you in the right direction.
Many beginners choose NiMH cells
because of their inherent safety, while others
choose the latest Li-Poly cells because of
their high energy capacity-to-weight ratio.
To add to the confusion, the new M1 cells
from A123Racing are Lithium-Ion
technology and are extremely safe.
Which is best? It depends on who you
ask and how the battery is being used. You
probably hate that answer, but it’s true.
One thing you can do is arm yourself
with the latest information that is accurate
and not just advertising hype. We’ve been
victims of a lot of that, and it’s usually hard
to weed through to the truth.
I encourage you to read Red
Scholefield’s “The Battery Clinic”
column, which alternates months with
mine. Also check out his Web site at
www.rcbatteryclinic.com. Red has more
battery experience and expertise than
anyone has a right to have, plus he’s an
active electric-power pilot.
Do not shop by price alone when it
comes to buying batteries! Do your
research and talk to others. Find out whose
cells are holding up well and who stands
behind the product.
Most important, buy the proper battery
for the job you’re doing. Don’t buy a Li-
Poly pack that is rated for 20C (20 times the
capacity; i.e., a 2100 mAh cell would be
rated for 42 amps) and use it for something
drawing 60 amps. To be even safer, I don’t
recommend using any cell past 75% of its
rated capacity.
Make the Connection: You have to hook it
all together somehow, and that involves
connectors. Which ones are best? Again—
an answer you’re not going to like—it all
depends. Fortunately what it depends on
most is your personal preference once you
know it’s capable of carrying the load.
In a photo are two sizes of bullet-style
connectors, and the larger one is a 6mm
competition plug that will carry the 100-
plus amps they need. Most sport fliers can
use any other connectors in the photo and
find they fit their needs nicely.
All the connectors require you to solder
the wire to the plug, and some are easier
than others to solder. My connector of
choice is the Anderson Powerpole for most
applications in the sport category.
I hate to solder, and for $50 I bought the
nicest crimping tool from West Mountain
Radio (www.westmountainradio.com) that
is designed to do one thing: crimp
powerpoles perfectly every time. I have
nothing against soldered connectors, and I use
a lot of them, but this method is quick, easy,
and avoids any problems associated with poor
soldering skills.
Between my motor and controller I prefer
either the AstroFlight Astro 3 Pin Zero Loss
Connector or the 3mm bullet plugs. It makes
it easy to swap a wire or flip the Zero Loss
connector around to fix any problem with
motor direction.
Choose the connector you’re happy with,
and try to standardize your usage to reduce
the number of adapters you’ll need. I have a
box full of adapters because I test so many
things that have various plugs on them. All
my batteries have Anderson Powerpoles, as
do my chargers, but I have adapters to convert
them to all the others “just in case.”
I’m working on an article that will go
much deeper into the various connectors and
their relative resistance, etc. that will be
published at a later date.
Charge It Up! So now you’ve decided on
your batteries and connectors; what next?
You have to charge those batteries, and the
market is exploding with chargers. There are
chargers that will do only Li-Polys and
chargers that will do only Ni-Cd or NiMH
cells. There are chargers that will do them all,
and there are chargers that will do them all,
log the data onto your computer, and allow
you to program any charge rate or cutoff
voltage.
How do you choose? What do you want to
pay, and what are your long-range goals for
Electrics?
I’ve shown the chargers I use in my shop,
and they all have a purpose I prefer for one
operation or another. My most recent
purchase is the Xtrema because of its
flexibility and the fact that lifetime upgrades
are offered with it. It’s not my most expensive
charger, but it’s beginning to look like it’s
going to be a favorite the more I use it.
I bought the Xtrema because I use Li-
Polys, but I also use the new A123Racing
cells, and their peak voltage cutoff for
charging is 3.6 rather than the usual 4.2 for
Li-Polys. I can program that into this charger.
My Orbit Pro is a high-end charger and the
cost reflects that, but it’s extremely versatile.
It also has the computer interface and will
charge Li-Poly, Ni-Cd, NiMH, or lead-acid
batteries. As with any of the chargers that “do
it all,” it’s important that you pay close
attention to what setting you have selected
prior to plugging any battery to it.
I’ve used AstroFlight chargers since I got
into Electrics, and I’ll always have one in the
shop. They are designed to do one type of
battery and do it well. If I were using only Li-
Polys my 109 Lithium Charger would keep
me from making a mistake by having the
wrong program selected.
The 112 Deluxe takes care of all the
NiMH and Ni-Cd cells I have, and I know
it won’t accidentally charge the wrong
type. These are the ultimate in simplicity,
and you manually dial in the current you
want for each charge.
The only balancing charger I have is the
one in the top right corner of the photo, and it
only does A123Racing Lithium-Ion batteries
from A123. The company designed the unit to
charge its “M1”-type cells.
That being said, I always balance my Li-
Poly and M1 batteries. I use an AstroFlight
Blinky to keep them balanced, and the little
$25 device is worth its weight in gold. There
is one for Li-Polys and one for A123 cells
because of the different voltage requirements.
The FMA Direct Cellpro charger is highly
recommended, but I don’t have one yet. Red
Scholefield has written about it and discussed
it with me, so I know it’s great. I trust Red
enough to know that it’s the next one I’ll add
to my shop. Check out his Web site for indepth
information about batteries and
chargers.
Last is the LipoDapter from SLK
Electronics (the maker of ElectriCalc), which
allows you to charge your Li-Poly or A123
batteries by using it in conjunction with a
regular charger such as the AstroFlight 112
Deluxe. The little $40 LipoDapter will let you
use a charger you may already have.
Final Approach: I’ve run way over my space
limit and made the editor’s job tougher this
month, so I better quit. I hope this will give
you some basic info about what equipment to
consider and how to find what you need. My
E-mail is always