122 MODEL AVIATION
A REALLY COOL tool showed up in the mail this month. Paul
Beard of Model Avionics (www.modelavionics.com) sent out the
Watt’s Up, which is being advertised as an electronic onboard
power meter for electric-powered RC helicopters. It was designed to
help tune the battery system and motor. However, I have found
other good uses for this device.
Some of the Watt’s Up key features are as follows.
• It measures energy (watt-hours [Wh]), charge (ampere-hours
[Ah]), power (watts [W]), current (amps [A]), and voltage (V).
• It has a connector to use a receiver battery for measurement down
to 0 volts.
• It features low-battery-voltage detection with an optional LED for
indication of low battery voltage while flying!
• It’s accurate and precise, with 0.01 A current and 0.01V voltage
resolutions.
• It measures current peaks and voltage minimum (droops)
• It’s rugged; it handles 50 A continuous and 100 A peak at 60V.
• It uses 14-gauge, 7 x 37-inch stranded, high-temperature silicone
rubber insulated wire.
• It’s small and light, measuring 2.8 inches long, 1.7 inches wide,
and 0.83 inch in diameter, and weighing 2.5 ounces.
• It acts like a wire so it doesn’t affect a model’s performance. It’s a
precision current-sensing resistor, with only 0.001 ohm resistance
and circuitry that draws only 0.007 amp.
• It uses DSP to increase ADC resolution and differential
measurement amplifiers to increase noise immunity.
• Factory calibration stores constants in EEPROM to compensate for
component tolerances.
• It comes with a one-year warranty and complete user’s manual.
• It’s made in the US to ISO 9001:2000 quality standards.
What does all of this mean to you and me? I have always wanted
an accurate way to determine not only how much battery power I
use in a flight, but the maximum current draw during the flight. I
think this is equally important because it gives a good indication of
not only how well our servos are doing, but how hard we are
working them. The Watt’s Up does this beautifully.
The Watt’s Up comes with bare wires, so the first thing you have
to do is solder the appropriate connectors to the wires. I made a
variety of adapters so that I can use the device in many different
applications.
The first test for the Watt’s Up was in our new Raptor 90SE.
This helicopter was completely built, set up, and ready for flight—or
so I thought. It has the Duralite 4000 mAh Li-Poly battery pack and
5.1-volt regulator. It has three JR DS8311 servos, one JR 810G
servo, and one JR 8700G servo. I installed the Watt’s Up between
the battery pack and the 5.1-volt regulator.
The Watt’s Up alternates between two displays on power-up,
Ray Stacy, 15 W. Main St., Webster NY 14580; E-mail: [email protected]
RADIO CONTROL HELICOPTERS
Watt’s Up with all servos idle. Current draw is 260 milliamps.
With throttle stick at low, current draw jumped to 2.26 amps.
Watt’s Up is installed between battery and 5.1-volt regulator.
showing peak amps, minimum volts, watts, and watt-hours or amps,
volts, watts, and ampere-hours.
Even if you don’t purchase the Watt’s Up, take a moment to
download its instructions from the Model Avionics Web site. Paul
Beard gives an excellent crash course on basic electronics and a
great description of what the various terms mean and how they
relate to our hobby.
Back to the Raptor. I found that in the idle state—midstick—the
current draw was approximately 260 milliamps. That seems about
right to me. Moving the sticks with no real load would draw roughly
1 amp. If I stalled one servo or tried to manually move a servo, I
could get more than 2 amps! Then I noticed something very strange.
With nothing moving and the stick at the low position, I was
drawing 2.26 amps. That’s not good! At midstick I was drawing 260
milliamps, and at low stick I was drawing more than 2!
I popped the collective link off, and the current dropped to 740
milliamps. That was better but still not right. I learned that I was
stalling the collective servo at low stick. A couple turns of the
collective link and the collective servo was
much happier, but I still wasn’t at the 260
milliamps idle current that I had at midstick.
I popped off the throttle link, and the
current draw was back to 260 milliamps.
After a couple turns of the throttle link, all
was well at all stick positions.
And remember that this is a helicopter
that I had set up and thought was ready to
fly. I do all of my initial mechanical setups
by leaving off one end of the link and
verifying that I am not creating a binding
condition. This helicopter was no different.
I had no visible or audible indication of a
stalled servo, but the Watt’s Up knew better. It
earned its keep in the first 10 minutes of use!
For the flight test I used my son Kyle’s
Raptor 50. I installed the Watt’s Up between
the battery pack and the switch. Knowing
that I could easily draw 2 amps by stalling a
servo, the idea with the in-flight test was to
see how much peak current could be
drawn during a flight under actual flying
loads. In other words, are we overloading
our servos and wiring?
May 2005 123
It took only a few minutes to install the Watt’s Up. I used a
couple of rubber bands to hold everything in place. Make sure you
do a good job of soldering on the connectors. Your helicopter’s life
depends on it.
I turned the model over to Kyle. He proceeded to do a heavy 3-D
flight that included many stick inputs and hard tail-rotor control. For
a 12-minute flight we used approximately 600 milliamps of battery
power and, interestingly enough, the maximum current drawn
during the flight was only 1.5 amps. Maybe that is only interesting
to me, but I always thought we were drawing more current with our
new high-tech, super-fast, digital servos.
Judging from that data—assuming there is no binding—we are
not pushing our servos, wiring, or switches past their design
limitations. Yes, sometimes our equipment fails, but I do not believe
it is because we asked for more than it could deliver.
For the next test, I will do the same thing on a couple of 90-
size machines and my Bergen gasser. It will be just as
interesting to me to see what current is being drawn in the
The author’s longtime helicopter friend Dave Darr with his new Trex from AlignRC. Dave
was instrumental in convincing Ray to purchase a Trex.
larger machines. Stay tuned.
Following are the Watt’s Up’s
specifications.
• Current: 0-100 A peak, 50 A
continuous, resolution 0.01 A.
• Voltage: 0-60V, resolution 0.01V.
• Power: 0-6500 W, resolution 0.1 W.
• Charge: 0-65 Ah, resolution 0.001 Ah.
• Energy: 0-6500 Wh, resolution 0.1 Wh.
• Operates from 4.0V to 60V. 0V with
optional receiver battery pack.
• 16 x 2 STN LCD display screen.
• Powerful 8 MIPS microcontroller.
By the time you read this, winter will
have subsided here and the fleet that we
worked on during the cold months will
be getting a workout. I would like tothink that it is time to put our micro
electrics away for the season, but I am
having way too much fun with the Trex
from AlignRC. I bought mine from Wes
Gray at www.modefosheli.com. He is great
to work with and responds quickly to all
mail notes.
Once I saw that longtime helicopter
friend Dave Darr had a Trex, I knew I had
to get my order in. At $164 shipped, I
simply couldn’t pass it up. The Trex is a
baby Raptor that builds well, flies well, and
is durable. Parts are also affordable.
The Trex’s 3-D performance is not
quite equal to my Hornet 2, but Vinnie
from JustGoFly.com has promised me a
new brushless motor that should do the
trick.
New on the bench for the glow
machines are the Raptor 90SE and the
Hirobo X-Spec. The Raptor 90 will be my
first experience with an O.S. C-Spec
engine. The X-Spec has a new YS 91 in it.
For all-out performance, my son and I
prefer a 90-powered machine. The 50s are
great and the gassers are nice, but they
don’t yet compare to the rocking
performance of a hot 90 running with a
muscle pipe and 30% fuel. We are looking
forward to giving both machines a good
run and will report back about how well
they are doing.
The Extreme Flight Championships, or
XFC (www.xfc-rc.com), is coming up. The
fourth annual Freestyle extravaganza will
be held June 10-12 in Troy, Ohio.
I have graciously been asked to judge. I
consider it an honor and have accepted,
even though Curtis Youngblood has said
that he doesn’t envy me! Being a judge
isn’t easy, but I will do my best.
Come on out and see the best 3-D pilots
Edition: Model Aviation - 2005/05
Page Numbers: 122,123,124
Edition: Model Aviation - 2005/05
Page Numbers: 122,123,124
122 MODEL AVIATION
A REALLY COOL tool showed up in the mail this month. Paul
Beard of Model Avionics (www.modelavionics.com) sent out the
Watt’s Up, which is being advertised as an electronic onboard
power meter for electric-powered RC helicopters. It was designed to
help tune the battery system and motor. However, I have found
other good uses for this device.
Some of the Watt’s Up key features are as follows.
• It measures energy (watt-hours [Wh]), charge (ampere-hours
[Ah]), power (watts [W]), current (amps [A]), and voltage (V).
• It has a connector to use a receiver battery for measurement down
to 0 volts.
• It features low-battery-voltage detection with an optional LED for
indication of low battery voltage while flying!
• It’s accurate and precise, with 0.01 A current and 0.01V voltage
resolutions.
• It measures current peaks and voltage minimum (droops)
• It’s rugged; it handles 50 A continuous and 100 A peak at 60V.
• It uses 14-gauge, 7 x 37-inch stranded, high-temperature silicone
rubber insulated wire.
• It’s small and light, measuring 2.8 inches long, 1.7 inches wide,
and 0.83 inch in diameter, and weighing 2.5 ounces.
• It acts like a wire so it doesn’t affect a model’s performance. It’s a
precision current-sensing resistor, with only 0.001 ohm resistance
and circuitry that draws only 0.007 amp.
• It uses DSP to increase ADC resolution and differential
measurement amplifiers to increase noise immunity.
• Factory calibration stores constants in EEPROM to compensate for
component tolerances.
• It comes with a one-year warranty and complete user’s manual.
• It’s made in the US to ISO 9001:2000 quality standards.
What does all of this mean to you and me? I have always wanted
an accurate way to determine not only how much battery power I
use in a flight, but the maximum current draw during the flight. I
think this is equally important because it gives a good indication of
not only how well our servos are doing, but how hard we are
working them. The Watt’s Up does this beautifully.
The Watt’s Up comes with bare wires, so the first thing you have
to do is solder the appropriate connectors to the wires. I made a
variety of adapters so that I can use the device in many different
applications.
The first test for the Watt’s Up was in our new Raptor 90SE.
This helicopter was completely built, set up, and ready for flight—or
so I thought. It has the Duralite 4000 mAh Li-Poly battery pack and
5.1-volt regulator. It has three JR DS8311 servos, one JR 810G
servo, and one JR 8700G servo. I installed the Watt’s Up between
the battery pack and the 5.1-volt regulator.
The Watt’s Up alternates between two displays on power-up,
Ray Stacy, 15 W. Main St., Webster NY 14580; E-mail: [email protected]
RADIO CONTROL HELICOPTERS
Watt’s Up with all servos idle. Current draw is 260 milliamps.
With throttle stick at low, current draw jumped to 2.26 amps.
Watt’s Up is installed between battery and 5.1-volt regulator.
showing peak amps, minimum volts, watts, and watt-hours or amps,
volts, watts, and ampere-hours.
Even if you don’t purchase the Watt’s Up, take a moment to
download its instructions from the Model Avionics Web site. Paul
Beard gives an excellent crash course on basic electronics and a
great description of what the various terms mean and how they
relate to our hobby.
Back to the Raptor. I found that in the idle state—midstick—the
current draw was approximately 260 milliamps. That seems about
right to me. Moving the sticks with no real load would draw roughly
1 amp. If I stalled one servo or tried to manually move a servo, I
could get more than 2 amps! Then I noticed something very strange.
With nothing moving and the stick at the low position, I was
drawing 2.26 amps. That’s not good! At midstick I was drawing 260
milliamps, and at low stick I was drawing more than 2!
I popped the collective link off, and the current dropped to 740
milliamps. That was better but still not right. I learned that I was
stalling the collective servo at low stick. A couple turns of the
collective link and the collective servo was
much happier, but I still wasn’t at the 260
milliamps idle current that I had at midstick.
I popped off the throttle link, and the
current draw was back to 260 milliamps.
After a couple turns of the throttle link, all
was well at all stick positions.
And remember that this is a helicopter
that I had set up and thought was ready to
fly. I do all of my initial mechanical setups
by leaving off one end of the link and
verifying that I am not creating a binding
condition. This helicopter was no different.
I had no visible or audible indication of a
stalled servo, but the Watt’s Up knew better. It
earned its keep in the first 10 minutes of use!
For the flight test I used my son Kyle’s
Raptor 50. I installed the Watt’s Up between
the battery pack and the switch. Knowing
that I could easily draw 2 amps by stalling a
servo, the idea with the in-flight test was to
see how much peak current could be
drawn during a flight under actual flying
loads. In other words, are we overloading
our servos and wiring?
May 2005 123
It took only a few minutes to install the Watt’s Up. I used a
couple of rubber bands to hold everything in place. Make sure you
do a good job of soldering on the connectors. Your helicopter’s life
depends on it.
I turned the model over to Kyle. He proceeded to do a heavy 3-D
flight that included many stick inputs and hard tail-rotor control. For
a 12-minute flight we used approximately 600 milliamps of battery
power and, interestingly enough, the maximum current drawn
during the flight was only 1.5 amps. Maybe that is only interesting
to me, but I always thought we were drawing more current with our
new high-tech, super-fast, digital servos.
Judging from that data—assuming there is no binding—we are
not pushing our servos, wiring, or switches past their design
limitations. Yes, sometimes our equipment fails, but I do not believe
it is because we asked for more than it could deliver.
For the next test, I will do the same thing on a couple of 90-
size machines and my Bergen gasser. It will be just as
interesting to me to see what current is being drawn in the
The author’s longtime helicopter friend Dave Darr with his new Trex from AlignRC. Dave
was instrumental in convincing Ray to purchase a Trex.
larger machines. Stay tuned.
Following are the Watt’s Up’s
specifications.
• Current: 0-100 A peak, 50 A
continuous, resolution 0.01 A.
• Voltage: 0-60V, resolution 0.01V.
• Power: 0-6500 W, resolution 0.1 W.
• Charge: 0-65 Ah, resolution 0.001 Ah.
• Energy: 0-6500 Wh, resolution 0.1 Wh.
• Operates from 4.0V to 60V. 0V with
optional receiver battery pack.
• 16 x 2 STN LCD display screen.
• Powerful 8 MIPS microcontroller.
By the time you read this, winter will
have subsided here and the fleet that we
worked on during the cold months will
be getting a workout. I would like tothink that it is time to put our micro
electrics away for the season, but I am
having way too much fun with the Trex
from AlignRC. I bought mine from Wes
Gray at www.modefosheli.com. He is great
to work with and responds quickly to all
mail notes.
Once I saw that longtime helicopter
friend Dave Darr had a Trex, I knew I had
to get my order in. At $164 shipped, I
simply couldn’t pass it up. The Trex is a
baby Raptor that builds well, flies well, and
is durable. Parts are also affordable.
The Trex’s 3-D performance is not
quite equal to my Hornet 2, but Vinnie
from JustGoFly.com has promised me a
new brushless motor that should do the
trick.
New on the bench for the glow
machines are the Raptor 90SE and the
Hirobo X-Spec. The Raptor 90 will be my
first experience with an O.S. C-Spec
engine. The X-Spec has a new YS 91 in it.
For all-out performance, my son and I
prefer a 90-powered machine. The 50s are
great and the gassers are nice, but they
don’t yet compare to the rocking
performance of a hot 90 running with a
muscle pipe and 30% fuel. We are looking
forward to giving both machines a good
run and will report back about how well
they are doing.
The Extreme Flight Championships, or
XFC (www.xfc-rc.com), is coming up. The
fourth annual Freestyle extravaganza will
be held June 10-12 in Troy, Ohio.
I have graciously been asked to judge. I
consider it an honor and have accepted,
even though Curtis Youngblood has said
that he doesn’t envy me! Being a judge
isn’t easy, but I will do my best.
Come on out and see the best 3-D pilots
Edition: Model Aviation - 2005/05
Page Numbers: 122,123,124
122 MODEL AVIATION
A REALLY COOL tool showed up in the mail this month. Paul
Beard of Model Avionics (www.modelavionics.com) sent out the
Watt’s Up, which is being advertised as an electronic onboard
power meter for electric-powered RC helicopters. It was designed to
help tune the battery system and motor. However, I have found
other good uses for this device.
Some of the Watt’s Up key features are as follows.
• It measures energy (watt-hours [Wh]), charge (ampere-hours
[Ah]), power (watts [W]), current (amps [A]), and voltage (V).
• It has a connector to use a receiver battery for measurement down
to 0 volts.
• It features low-battery-voltage detection with an optional LED for
indication of low battery voltage while flying!
• It’s accurate and precise, with 0.01 A current and 0.01V voltage
resolutions.
• It measures current peaks and voltage minimum (droops)
• It’s rugged; it handles 50 A continuous and 100 A peak at 60V.
• It uses 14-gauge, 7 x 37-inch stranded, high-temperature silicone
rubber insulated wire.
• It’s small and light, measuring 2.8 inches long, 1.7 inches wide,
and 0.83 inch in diameter, and weighing 2.5 ounces.
• It acts like a wire so it doesn’t affect a model’s performance. It’s a
precision current-sensing resistor, with only 0.001 ohm resistance
and circuitry that draws only 0.007 amp.
• It uses DSP to increase ADC resolution and differential
measurement amplifiers to increase noise immunity.
• Factory calibration stores constants in EEPROM to compensate for
component tolerances.
• It comes with a one-year warranty and complete user’s manual.
• It’s made in the US to ISO 9001:2000 quality standards.
What does all of this mean to you and me? I have always wanted
an accurate way to determine not only how much battery power I
use in a flight, but the maximum current draw during the flight. I
think this is equally important because it gives a good indication of
not only how well our servos are doing, but how hard we are
working them. The Watt’s Up does this beautifully.
The Watt’s Up comes with bare wires, so the first thing you have
to do is solder the appropriate connectors to the wires. I made a
variety of adapters so that I can use the device in many different
applications.
The first test for the Watt’s Up was in our new Raptor 90SE.
This helicopter was completely built, set up, and ready for flight—or
so I thought. It has the Duralite 4000 mAh Li-Poly battery pack and
5.1-volt regulator. It has three JR DS8311 servos, one JR 810G
servo, and one JR 8700G servo. I installed the Watt’s Up between
the battery pack and the 5.1-volt regulator.
The Watt’s Up alternates between two displays on power-up,
Ray Stacy, 15 W. Main St., Webster NY 14580; E-mail: [email protected]
RADIO CONTROL HELICOPTERS
Watt’s Up with all servos idle. Current draw is 260 milliamps.
With throttle stick at low, current draw jumped to 2.26 amps.
Watt’s Up is installed between battery and 5.1-volt regulator.
showing peak amps, minimum volts, watts, and watt-hours or amps,
volts, watts, and ampere-hours.
Even if you don’t purchase the Watt’s Up, take a moment to
download its instructions from the Model Avionics Web site. Paul
Beard gives an excellent crash course on basic electronics and a
great description of what the various terms mean and how they
relate to our hobby.
Back to the Raptor. I found that in the idle state—midstick—the
current draw was approximately 260 milliamps. That seems about
right to me. Moving the sticks with no real load would draw roughly
1 amp. If I stalled one servo or tried to manually move a servo, I
could get more than 2 amps! Then I noticed something very strange.
With nothing moving and the stick at the low position, I was
drawing 2.26 amps. That’s not good! At midstick I was drawing 260
milliamps, and at low stick I was drawing more than 2!
I popped the collective link off, and the current dropped to 740
milliamps. That was better but still not right. I learned that I was
stalling the collective servo at low stick. A couple turns of the
collective link and the collective servo was
much happier, but I still wasn’t at the 260
milliamps idle current that I had at midstick.
I popped off the throttle link, and the
current draw was back to 260 milliamps.
After a couple turns of the throttle link, all
was well at all stick positions.
And remember that this is a helicopter
that I had set up and thought was ready to
fly. I do all of my initial mechanical setups
by leaving off one end of the link and
verifying that I am not creating a binding
condition. This helicopter was no different.
I had no visible or audible indication of a
stalled servo, but the Watt’s Up knew better. It
earned its keep in the first 10 minutes of use!
For the flight test I used my son Kyle’s
Raptor 50. I installed the Watt’s Up between
the battery pack and the switch. Knowing
that I could easily draw 2 amps by stalling a
servo, the idea with the in-flight test was to
see how much peak current could be
drawn during a flight under actual flying
loads. In other words, are we overloading
our servos and wiring?
May 2005 123
It took only a few minutes to install the Watt’s Up. I used a
couple of rubber bands to hold everything in place. Make sure you
do a good job of soldering on the connectors. Your helicopter’s life
depends on it.
I turned the model over to Kyle. He proceeded to do a heavy 3-D
flight that included many stick inputs and hard tail-rotor control. For
a 12-minute flight we used approximately 600 milliamps of battery
power and, interestingly enough, the maximum current drawn
during the flight was only 1.5 amps. Maybe that is only interesting
to me, but I always thought we were drawing more current with our
new high-tech, super-fast, digital servos.
Judging from that data—assuming there is no binding—we are
not pushing our servos, wiring, or switches past their design
limitations. Yes, sometimes our equipment fails, but I do not believe
it is because we asked for more than it could deliver.
For the next test, I will do the same thing on a couple of 90-
size machines and my Bergen gasser. It will be just as
interesting to me to see what current is being drawn in the
The author’s longtime helicopter friend Dave Darr with his new Trex from AlignRC. Dave
was instrumental in convincing Ray to purchase a Trex.
larger machines. Stay tuned.
Following are the Watt’s Up’s
specifications.
• Current: 0-100 A peak, 50 A
continuous, resolution 0.01 A.
• Voltage: 0-60V, resolution 0.01V.
• Power: 0-6500 W, resolution 0.1 W.
• Charge: 0-65 Ah, resolution 0.001 Ah.
• Energy: 0-6500 Wh, resolution 0.1 Wh.
• Operates from 4.0V to 60V. 0V with
optional receiver battery pack.
• 16 x 2 STN LCD display screen.
• Powerful 8 MIPS microcontroller.
By the time you read this, winter will
have subsided here and the fleet that we
worked on during the cold months will
be getting a workout. I would like tothink that it is time to put our micro
electrics away for the season, but I am
having way too much fun with the Trex
from AlignRC. I bought mine from Wes
Gray at www.modefosheli.com. He is great
to work with and responds quickly to all
mail notes.
Once I saw that longtime helicopter
friend Dave Darr had a Trex, I knew I had
to get my order in. At $164 shipped, I
simply couldn’t pass it up. The Trex is a
baby Raptor that builds well, flies well, and
is durable. Parts are also affordable.
The Trex’s 3-D performance is not
quite equal to my Hornet 2, but Vinnie
from JustGoFly.com has promised me a
new brushless motor that should do the
trick.
New on the bench for the glow
machines are the Raptor 90SE and the
Hirobo X-Spec. The Raptor 90 will be my
first experience with an O.S. C-Spec
engine. The X-Spec has a new YS 91 in it.
For all-out performance, my son and I
prefer a 90-powered machine. The 50s are
great and the gassers are nice, but they
don’t yet compare to the rocking
performance of a hot 90 running with a
muscle pipe and 30% fuel. We are looking
forward to giving both machines a good
run and will report back about how well
they are doing.
The Extreme Flight Championships, or
XFC (www.xfc-rc.com), is coming up. The
fourth annual Freestyle extravaganza will
be held June 10-12 in Troy, Ohio.
I have graciously been asked to judge. I
consider it an honor and have accepted,
even though Curtis Youngblood has said
that he doesn’t envy me! Being a judge
isn’t easy, but I will do my best.
Come on out and see the best 3-D pilots
