Also included in this column:
• Electronic Speed Controls
Troubleshooting continues
Electrics Greg Gimlick | [email protected]
Jeti Advance offers a programming card
that is easily set by moving jumpers.
Castle Creations also has a use-alone, easyto-
run programming card.
Castle Creations has a great tool to
program your ESC from your laptop.
TAKING OFF: I’m going to continue with
troubleshooting issues we discussed last time.
I’ll concentrate mostly on Electronic Speed
Controls (ESCs), because often that is where
problems lie and it’s not always obvious.
Size Matters: Many problems people run
into with a setup not running properly have to
do with choices they’ve made and the reasons
behind them. One such choice has to do with
the size of the speed control. I’m not talking
about physical size, but “electronic” size.
They’re choosing an ESC that just isn’t up to
the task.
If your setup is going to pull 60 amps at
full throttle, you need to select an ESC that is
rated for at least 60 amps, and I would
recommend going beyond that. A common
argument is, “But I’m going to be flying at
half throttle most of the time, so I thought I
could get away with a 45-amp ESC.” That
doesn’t hold water—or electrons!
At the most basic level, an ESC is nothing
more than a switch. The controller is either
full on or off all the time. It turns on and off
thousands of times a second and the time it’s
on or off varies by throttle position. All the
way off means there is no power being sent
to the motor; all the way on means it is being
sent to the motor. Any throttle position
between off and on means the ESC is
switching on and off to achieve the power
required for that position.
Why do we care? What it means is if your
system draws 60 amps at full throttle, it also
draws 60 amps at half throttle. It’s only there
for a microsecond at a time, but it’s still 60
amps. You can’t expect a 45-amp controller
to handle the setup even at half throttle. If
I’m planning a setup to pull 60 amps, I like to
use a controller that is rated closer to 80
amps. That gives me plenty of safety
headroom for spikes, etc. Bigger is better if
you have the room.
Basic Rules of ESCs: Read the instructions!
This may sound elementary, but it’s the
number-one reason behind most of the
questions I get and it’s why people manage to
damage equipment. Instructions for ESCs are
not that exciting, but they are terribly
important. I can’t overemphasize that
enough. The instructions not only tell you
about the programming options, but they tell
you how to avoid damaging your airplane or
equipment. They include important safety
tips, so read them!
Equally significant, the directions tell you
how to enter the programming mode of the
controller so you can adjust it to fit your
needs. Some controllers can be programmed
with external devices, but all can be
programmed through a series of stick
movements on the transmitter, while listening
to the tones emitted by the controller/motor.
Always remove the propeller (or rotor
blades) before programming. Never trust an
armed controller. Controllers are smarter and
safer than ever, but I treat them as if they are
about to start up, whether or not they have
arming switches. Never leave a motor battery
plugged into a controller, even if there is an
arming switch. A slight current drain will
eventually kill your battery, so always
remove the battery when you’re done flying.
Basic Settings: Controllers have myriad
features that can be changed to optimize your
system. Some you will use and others you
will disable. I’ll cover the most common
elements. In most cases, your controller will
come with factory defaults that are suitable
for 90% of user applications.
Brake Setting: Most controllers will let you
decide if you want a brake set or not. The
brake can be set to “on” if you want your
propeller to stop when you reduce your
throttle to idle/off. This is mostly used for
folding propellers, but some prefer to stop
their propeller for better glide with the motor
off even if it’s not a folding type.
There are settings for soft brake, hard
brake, and no brake. The default for most
manufacturers is no brake or soft brake, but
again, read the instructions. Some Jeti
controllers default to full brake. If you’re
flying a helicopter, you’ll want to be sure the
brake is set to off.
Choose an ESC powerful enough for the
job. The author’s setup pulls 120 amps, so
he chose a 160-amp ESC.
92 MODEL AVIATION
Left: FlightTech has an easy-to-use program for your laptop.
Below: Don’t forget about the help files; they’re full of useful
information about settings.
Low-Voltage Cutoff: This feature ensures
you don’t damage your LiPo pack by
drawing the voltage too low during a flight.
The default on most controllers is “auto,” and
most of the time that is just fine. Various
brands use different methods to determine
that, but the standard is roughly 70% to 75%
of the voltage level detected when first
armed.
This is important because if you fly more
than one flight on a pack without recharging
between flights, the controller may
misinterpret the number of cells and therefore
allow the voltage to drop too low. A threecell
LiPo pack is fully charged at 12.6 volts
and the nominal voltage is 11.1 volts. The
ESC accurately detects the cell count and sets
the cutoff at 75% or 9 volts, assuming it sees
12 volts when you connect it.
You make a flight and land with plenty of
power left. After a break, you reconnect the
same pack without charging and the ESC
detects 11.5 volts. Now it sets the cutoff at
75% or 8.12 volts. That’s too low for a threecell
pack; you’ve discharged it to 2.8 volts
per cell and they don’t like much below 3
volts per cell. This particular example
illustrates the potential problem with multiple
flights before recharging.
Check your ESC instructions. Most ESCs
will emit a tone upon arming that says how
many cells the ESC thinks are in your pack.
Be sure to verify it is correct before flying.
Some controllers allow you to override the
auto setting and select a minimum discharge
voltage. Always fly with a freshly charged
pack so the controller has the best chance of
properly identifying the cell count.
Cutoff Mode: Most controllers will allow
you to choose whether you want a hard or
soft cutoff when it reaches its minimum
voltage level. A hard cutoff means your
motor is going to stop when the voltage is
reached. A soft cutoff means the motor will
pulse on and off to let you know it’s time to
land.
When the cutoff activates, you can often
reduce your throttle to idle for a second and
then return to normal operation long enough
to land the aircraft. Don’t abuse this
capability; it is overriding the cutoff and
meant to give you power to avoid a deadstick
landing. Helicopter pilots will want a
soft cutoff or likely none at all because it
would stop the motor and put the heli into
an autorotative state.
Start-up Mode: This defines how the
motor starts when you open the throttle.
The choices are generally “normal,” “soft
start,” and “super soft start” or something
similar. It’s self-explanatory. Normal is
usually the default mode and fine for most
airplanes.
If you’re flying an airplane with a
gearbox, you might want a soft start to
make it easier on the gears and motor when
it starts up. If you are flying a helicopter,
you will want a soft start most of the time
to soften the strain on the main gear while
the motor attempts to get the rotor blades
started. If you use normal on a helicopter, it
can often strip a gear.
Timing: This causes more questions than a
paragraph or two can answer. The default for
most ESCs is “standard” or “medium.”
Unless you want to learn motor theory and
optimize for competition, you’re safe leaving
this alone. The instructions will give you
special notes in case you have a problem
with your motor not running smoothly.
Pulse-Width Modulation (PWM)
Switching Frequency: Stick with the factory
defaults unless there is a problem. If you
encounter a problem, check the instructions
again or contact technical support. A full
description of PWM is beyond the scope of
this introduction. This figure represents
the number of times per second that a
pulse is sent to the motor. This may be
between 8,000 and 32,000 times per second.
Operating Mode: Some controllers give the
options of selecting a preprogrammed set of
parameters such as “airplane,” “glider,” or
“helicopter.” When choosing one of these
operating modes, the ESC will have preset
features to optimize that choice.
When choosing helicopter, many will let
you activate a governor mode to help with
throttle/collective coordination and use the
softest start mode. I’ll discuss this more in the
next column. The glider mode usually sets a
hard brake assuming you’re using a folding
propeller.
One Last Thing: I receive many questions
about how to connect the three wires to the
motors. This one is easy—it doesn’t matter.
Hook them up in any order and if the motor
runs backward, change any two wires. You
won’t hurt a thing.
Some ESCs will also let you reverse the
direction of the motor in its programming.
Final Approach: There is much more to
ESCs than we’ve touched on here, but I’ll go
into more detail on some of the features next
time. This should get you over the main
stumbling blocks and help avoid the most
common problems.
I hope you all have a very happy holiday
season and a great New Year! MA
Sources:
Castle Creations
(913) 390-6939
www.castlecreations.com
Edition: Model Aviation - 2011/12
Page Numbers: 91,92
Edition: Model Aviation - 2011/12
Page Numbers: 91,92
Also included in this column:
• Electronic Speed Controls
Troubleshooting continues
Electrics Greg Gimlick | [email protected]
Jeti Advance offers a programming card
that is easily set by moving jumpers.
Castle Creations also has a use-alone, easyto-
run programming card.
Castle Creations has a great tool to
program your ESC from your laptop.
TAKING OFF: I’m going to continue with
troubleshooting issues we discussed last time.
I’ll concentrate mostly on Electronic Speed
Controls (ESCs), because often that is where
problems lie and it’s not always obvious.
Size Matters: Many problems people run
into with a setup not running properly have to
do with choices they’ve made and the reasons
behind them. One such choice has to do with
the size of the speed control. I’m not talking
about physical size, but “electronic” size.
They’re choosing an ESC that just isn’t up to
the task.
If your setup is going to pull 60 amps at
full throttle, you need to select an ESC that is
rated for at least 60 amps, and I would
recommend going beyond that. A common
argument is, “But I’m going to be flying at
half throttle most of the time, so I thought I
could get away with a 45-amp ESC.” That
doesn’t hold water—or electrons!
At the most basic level, an ESC is nothing
more than a switch. The controller is either
full on or off all the time. It turns on and off
thousands of times a second and the time it’s
on or off varies by throttle position. All the
way off means there is no power being sent
to the motor; all the way on means it is being
sent to the motor. Any throttle position
between off and on means the ESC is
switching on and off to achieve the power
required for that position.
Why do we care? What it means is if your
system draws 60 amps at full throttle, it also
draws 60 amps at half throttle. It’s only there
for a microsecond at a time, but it’s still 60
amps. You can’t expect a 45-amp controller
to handle the setup even at half throttle. If
I’m planning a setup to pull 60 amps, I like to
use a controller that is rated closer to 80
amps. That gives me plenty of safety
headroom for spikes, etc. Bigger is better if
you have the room.
Basic Rules of ESCs: Read the instructions!
This may sound elementary, but it’s the
number-one reason behind most of the
questions I get and it’s why people manage to
damage equipment. Instructions for ESCs are
not that exciting, but they are terribly
important. I can’t overemphasize that
enough. The instructions not only tell you
about the programming options, but they tell
you how to avoid damaging your airplane or
equipment. They include important safety
tips, so read them!
Equally significant, the directions tell you
how to enter the programming mode of the
controller so you can adjust it to fit your
needs. Some controllers can be programmed
with external devices, but all can be
programmed through a series of stick
movements on the transmitter, while listening
to the tones emitted by the controller/motor.
Always remove the propeller (or rotor
blades) before programming. Never trust an
armed controller. Controllers are smarter and
safer than ever, but I treat them as if they are
about to start up, whether or not they have
arming switches. Never leave a motor battery
plugged into a controller, even if there is an
arming switch. A slight current drain will
eventually kill your battery, so always
remove the battery when you’re done flying.
Basic Settings: Controllers have myriad
features that can be changed to optimize your
system. Some you will use and others you
will disable. I’ll cover the most common
elements. In most cases, your controller will
come with factory defaults that are suitable
for 90% of user applications.
Brake Setting: Most controllers will let you
decide if you want a brake set or not. The
brake can be set to “on” if you want your
propeller to stop when you reduce your
throttle to idle/off. This is mostly used for
folding propellers, but some prefer to stop
their propeller for better glide with the motor
off even if it’s not a folding type.
There are settings for soft brake, hard
brake, and no brake. The default for most
manufacturers is no brake or soft brake, but
again, read the instructions. Some Jeti
controllers default to full brake. If you’re
flying a helicopter, you’ll want to be sure the
brake is set to off.
Choose an ESC powerful enough for the
job. The author’s setup pulls 120 amps, so
he chose a 160-amp ESC.
92 MODEL AVIATION
Left: FlightTech has an easy-to-use program for your laptop.
Below: Don’t forget about the help files; they’re full of useful
information about settings.
Low-Voltage Cutoff: This feature ensures
you don’t damage your LiPo pack by
drawing the voltage too low during a flight.
The default on most controllers is “auto,” and
most of the time that is just fine. Various
brands use different methods to determine
that, but the standard is roughly 70% to 75%
of the voltage level detected when first
armed.
This is important because if you fly more
than one flight on a pack without recharging
between flights, the controller may
misinterpret the number of cells and therefore
allow the voltage to drop too low. A threecell
LiPo pack is fully charged at 12.6 volts
and the nominal voltage is 11.1 volts. The
ESC accurately detects the cell count and sets
the cutoff at 75% or 9 volts, assuming it sees
12 volts when you connect it.
You make a flight and land with plenty of
power left. After a break, you reconnect the
same pack without charging and the ESC
detects 11.5 volts. Now it sets the cutoff at
75% or 8.12 volts. That’s too low for a threecell
pack; you’ve discharged it to 2.8 volts
per cell and they don’t like much below 3
volts per cell. This particular example
illustrates the potential problem with multiple
flights before recharging.
Check your ESC instructions. Most ESCs
will emit a tone upon arming that says how
many cells the ESC thinks are in your pack.
Be sure to verify it is correct before flying.
Some controllers allow you to override the
auto setting and select a minimum discharge
voltage. Always fly with a freshly charged
pack so the controller has the best chance of
properly identifying the cell count.
Cutoff Mode: Most controllers will allow
you to choose whether you want a hard or
soft cutoff when it reaches its minimum
voltage level. A hard cutoff means your
motor is going to stop when the voltage is
reached. A soft cutoff means the motor will
pulse on and off to let you know it’s time to
land.
When the cutoff activates, you can often
reduce your throttle to idle for a second and
then return to normal operation long enough
to land the aircraft. Don’t abuse this
capability; it is overriding the cutoff and
meant to give you power to avoid a deadstick
landing. Helicopter pilots will want a
soft cutoff or likely none at all because it
would stop the motor and put the heli into
an autorotative state.
Start-up Mode: This defines how the
motor starts when you open the throttle.
The choices are generally “normal,” “soft
start,” and “super soft start” or something
similar. It’s self-explanatory. Normal is
usually the default mode and fine for most
airplanes.
If you’re flying an airplane with a
gearbox, you might want a soft start to
make it easier on the gears and motor when
it starts up. If you are flying a helicopter,
you will want a soft start most of the time
to soften the strain on the main gear while
the motor attempts to get the rotor blades
started. If you use normal on a helicopter, it
can often strip a gear.
Timing: This causes more questions than a
paragraph or two can answer. The default for
most ESCs is “standard” or “medium.”
Unless you want to learn motor theory and
optimize for competition, you’re safe leaving
this alone. The instructions will give you
special notes in case you have a problem
with your motor not running smoothly.
Pulse-Width Modulation (PWM)
Switching Frequency: Stick with the factory
defaults unless there is a problem. If you
encounter a problem, check the instructions
again or contact technical support. A full
description of PWM is beyond the scope of
this introduction. This figure represents
the number of times per second that a
pulse is sent to the motor. This may be
between 8,000 and 32,000 times per second.
Operating Mode: Some controllers give the
options of selecting a preprogrammed set of
parameters such as “airplane,” “glider,” or
“helicopter.” When choosing one of these
operating modes, the ESC will have preset
features to optimize that choice.
When choosing helicopter, many will let
you activate a governor mode to help with
throttle/collective coordination and use the
softest start mode. I’ll discuss this more in the
next column. The glider mode usually sets a
hard brake assuming you’re using a folding
propeller.
One Last Thing: I receive many questions
about how to connect the three wires to the
motors. This one is easy—it doesn’t matter.
Hook them up in any order and if the motor
runs backward, change any two wires. You
won’t hurt a thing.
Some ESCs will also let you reverse the
direction of the motor in its programming.
Final Approach: There is much more to
ESCs than we’ve touched on here, but I’ll go
into more detail on some of the features next
time. This should get you over the main
stumbling blocks and help avoid the most
common problems.
I hope you all have a very happy holiday
season and a great New Year! MA
Sources:
Castle Creations
(913) 390-6939
www.castlecreations.com
