RADIO CONTROL HELICOPTERS - 2004/08

August 2004 123
FOR US NORTHERNERS, going to
Toledo, Ohio, in April is like getting that last
“shot in the arm” to help carry us through
from winter to flying season. The Weak
Signals’ show is awesome for a first-timer.
Almost everybody you read about is there.
It may be the only time we helicopter
pilots to get to visit the manufacturers and talk
to them face to face about products. This year
I visited with a couple of manufacturers: one
that makes helicopters and one that makes
batteries.
This year I decided to take care of one of
the worries that has always played in the back
of my mind. I’ve heard stories of batteryswitch
failures, but I never experienced one.
I’ve seen the results, though. Now that my
machines are starting to cost more than a
couple of healthy paychecks, I figured I’d
better address this issue before I lose my
investment.
I looked at a couple of the switched
regulator setups at the show. Basically,
they’re for running five or six Ni-Cd or
NiMH cells, and the regulators will drop the
voltage for the receiver and servos.
As part of the setup, a MOSFET switch
actually controls the battery connection to the
receiver system, and the mechanical switch
controls the MOSFET. If the mechanical
switch fails, the worst that can happen is that
you will be unable to turn off the receiver.
The system will fail “on” instead of “off.”
I didn’t want to carry the extra weight of
one or two more cells so that the regulator
would work, and the regulators were set up
for 6 volts of output to the receiver and
servos. Many of the helicopter gyros don’t
Dan Williams, 27 Treeline Dr., Liverpool NY 13090; E-mail: [email protected]
RADIO CONTROL HELICOPTERS
Duralite 4000 mAh Li-Ion battery with a Duralite 5.1-volt switched regulator. One wire on
the battery goes to the receiver, and the other wire is for charging.
The Duralite digital load tester is shown hooked up to the battery. By pressing one of
the buttons, you select either a 1⁄2- or a 1-amp load.
like seeing a voltage that high.
Radio South has a series of integrated
switch/regulator setups, and the company said
that it would make some without the regulator
for four-cell users. There may be others out
there, but I haven’t investigated it all that
much. This may be an option for anyone who
is looking for such a switch. Go to
www.radiosouthrc.com for more information
and contacts.
Later that day at the show I ran into a
friend who had his helicopter on display. He
was using Duralite batteries, and he had a
regulator from the company that was set for
5.1 volts. He told me to check with Duralite,
which had a booth at the show, so I paid a
visit. As I pointed out, most everybody is at
Toledo.
Duralite has a line of Lithium-Ion (Li-Ion)
and Li-Poly batteries, and it has chargers for
each that are specifically designed to work
with its batteries. This company has taken
battery safety and reliability to the next level.
There is increasing press about battery fires
and ruined packs from mischarging. One can
also ruin batteries from discharging too
deeply.
A way to prevent the problem of
overcharging is to make the charger more
intelligent. That is how some of the Li-Ion
and Li-Poly battery manufacturers have
decided to proceed. Whether this sufficiently
protects the cells from ruin and the possibility
of fires remains to be seen. By the time you
read this, AMA will have released a safety
advisory regarding Lithium batteries to help
educate modelers on the issue’s seriousness.
Another method of protecting the batteries
is to make the battery pack more intelligent.
This is the direction Duralite has taken with
its battery offerings. Duralite Lithium
batteries contain circuitry that monitors and
controls the charging process in their packs;
it’s called “Charge Safe Circuitry” and is a
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124 MODEL AVIATION
trademark name for the system.
Each Lithium cell measures 3.7 volts
during its useful life, and using two cells in
parallel raises that voltage to 7.4. Putting
another two series cells in parallel will create
the necessary capacity. Duralite’s internal
circuitry will monitor each cell’s voltage and
the total pack voltage for any overcharge
condition. It will then shut down the
charging process.
This charging process is done through a
separate charge plug coming out of the
complete pack and is completed through the
use of a Duralite Plus charger. It is a
complete and safe system for charging
Lithium cells.
Because the final voltage is 7.4, it must
be reduced to a proper level for receiver
This charger can accommodate as many as four receiver packs
at once. It is meant to work with the Charge Safe Circuitry.
At his RC Helis Plus booth, Len Sabato flies a Hoverfly in Cobra
dress “nose-in” to the camera, just right of his head.
systems—typically 5.1 or 5.6 volts for
helicopters. Duralite has a regulator system
that works in conjunction with its batteries to
provide the correct voltage.
In addition, you can purchase Duralite’s
regulators with a fail-safe switch. It is an
electronic switch that is controlled by a
mechanical toggle, which is the normal on/off
control. If this mechanical switch fails, the
electronic switch will remain on.
The worst that can happen if the switch
fails is that you won’t be able to turn the model
off and you’ll have to unplug the battery. That
is the situation I’ve worried about for a long
time, and Duralite has the solution.
There’s one more piece to the batteryprotection
puzzle, and that is in the case where
the discharge is too deep. With just one deep
discharge that is less than 5.5 volts for a
typical 7.4-volt pack, it’s all over for the
pack. It will be damaged beyond help, and
capacity will be drastically reduced.
Duralite has a digital load tester for
monitoring battery-pack voltage. It will put a
1-amp load on the battery and read out the
voltage before each flight. If the voltage is
approaching 5.5 volts, don’t fly. This is
extremely important to the battery pack’s
overall health.
I bought the 4000 mAh flat pack, which is
recommended for 60-size helicopters with
digital servos. It has a four-cell series/parallel
arrangement, as I mentioned earlier with
regard to the regulator. This pack has internal
redundancy in case one cell is lost. It weighs
less than 8 ounces, which is much lighter
than the 2000 mAH Ni-Cd pack I am
replacing.
I also purchased Duralite’s four-output
charger that will charge three receiver packs
and a transmitter pack simultaneously. It runs
from a 12-volt source such as a vehicle
battery, or you can purchase an AC charger.
Of course I got Duralite’s switched
regulator. I opted for the 5.1-volt output
based on the recommendation from fellow
helicopter pilot Jeff Swartz, who flies
Duralite batteries in his Robbe Millenniums.
After some thought, I finally decided to
buy Duralite’s digital load tester. At first I
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126 MODEL AVIATION
thought I should be able to come up with
something easily since I’m an electronics
engineer. I don’t know about you, but when
I get home from work, I don’t feel much like
doing the same type of work I do all day, so
I caved and got the tester. I like gadgets in
my flight box anyway.
Go to www.duralitebatteries.com for
plenty of good information about the
company’s systems. You’ll see that these
batteries get a great deal of use in Giant
Scale aircraft and jets, so those who are
looking for high performance, light weight,
and reliability in their expensive helicopters
are in good company.
Those were the majority of my purchases
at the Toledo expo. Outfitting two
helicopters with Li-Ion batteries and all the
paraphernalia can set you back a bit.
However, one more thing caught my eye
at the show. I have one of Radio South’s
Pro-Driver II glow-plug igniters, and the
case is big. The company has redesigned the
case, and it’s much smaller and would fit in
my flight box much better. It is known as
the Pro-Driver III. Go to the Web site for
more information.
RC Helis Plus is the new name of Len
Sabato’s company. I mentioned his
company in the previous column about the
CSM gyro. Go to www.rchelisplus.com and
save it in your browser’s Favorites folder.
I received an E-mail from someone the
other day, thanking me for explaining Idle
Up. He wrote that he had asked other
helicopter pilots at his field, but they didn’t
give him much of an explanation.
It troubles me when I hear things like
this. I guess many people think they
shouldn’t give anything back to the hobby
after they learn to fly helicopters. Helping
the newbies get going can help your club
sustain itself. Without them, your club could
stagnate and fall apart.
If I had blown off all the beginners I
have helped throughout the years, I
would never have made all the good
friends in the club and hobby from it.
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August issue of Model Aviation.
Give the poor newbie a hand, please?
If you happen to be in the Northeast August
27-29, stop at the Northeast Model
Helicopter Jamboree in Rochester, New
York. The Rochester AeroModeling Society
and Performance Hobbies will sponsor it
again. I’m involved in the event, so don’t
ding me too bad for promoting it.
We have had hardly any helicopter events
in upstate New York, so we’re counting on
this one to make a name for itself. Curtis
Youngblood will be back, and he promises to
take more of the jabs and abuse that we gave
him last year.
Go to www.rcplane.com for more
information. Yup! An airplane club is
hosting a helicopter event. Who would have
thunk it?
This may not be the most appropriate place
to discuss the following, but I’m on the
AMA Frequency Committee, and I’ve heard
rumblings and rumors about the lack of
progress AMA is making with respect to the
Broadband Over Powerline (BPL) issue. If
you don’t know what that is, go online and
search for “BPL.” You’ll learn more than
you’ll ever want to know.
By the time you read this, the comment
period for the Notice of Proposed
Rulemaking will have passed. Everyone on
the committee is working hard with our
lawyers to determine the impact on our
frequencies and respond to the FCC in
writing, along with all the other users who
may be affected.
There is a huge amount of
misinformation out there. If you wonder
where our AMA dues money goes every
year, defending our frequencies is one place.
The Frequency Committee is involved with
testing to help determine any effect on our
frequencies, and I am involved with this.
The best place to get the real scoop is the
AMA site: www.modelaircraft.org. See
where your dollars are spent.
Until next month, remember that every
model has an invisible expiration date. MA
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