Bob Aberle
F r e q u e n t l y A s k e d Q u e s t i o n s
E-mail: [email protected]
A close-up of the Castle Creations PH-Link (for the Phoenix
ESCs), as part of the supplied programming cable.
Bob hasn’t tried this tachometer, but the feature that lets you
save the last three rpm readings is worth looking into.
Bob purchased these CDs from Tom Wilk, who offers a set of 16.
They cover almost every facet of aeromodeling.
THIS IS THE 11th monthly column in which you write in or Email
your questions, and I try to give you the best possible answers.
Each question is given a sequential number for identification
purposes. Because publication space is limited, part of each month’s
installment will appear here, and the columns in their entirety are
posted on the AMA Web site at www.modelaircraft.org/
mag/faq/index.asp.
Let’s get started!
Q89: “I’m beginning to realize that more and more magazines, the
AMA, and even private individuals are making available archives of
previously published model aircraft articles, plans, three-views,
photos, etc. Searching for this type of data can present problems at
times, depending on how the search program is organized.
“Keeping all of this in mind, could you recommend a good
starting point for me as I attempt to look up model aircraft designs of
yesterday?”
A89: AMA has established a digital archives of articles published in
MA from 1975 until 2000. (A notice concerning this service was
published in the June 2004 issue on page 36.)
In the Vintage Radio Control Society newsletter I noticed a
reference to a private archives service run by Tom Wilk of Duluth,
Minnesota. He offers a series of CDs that contains all kinds of
historical model-aircraft data. He currently has 16 CDs, and that
number is constantly growing.
You can obtain a complete listing of what Tom has available by
sending an E-mail to him at [email protected]. His mailing
address is 301 W. Redwing St., Duluth MN 55803. His telephone
number is (218) 724-0928. Each CD costs $10 including postage in
the US. Canadian and international orders can be filled at a slightly
higher cost.
I was curious, so I purchased three CDs: “SAM Legal Antique &
Old Timer F/F Gas” (#9), “SAM Legal Nostalgia F/F Gas” (#10),
and “Early Sport R/C” (#16).
I was surprised when I opened the first selection. Each CD has an
index identifying every article on that particular disc. Each model is
contained in a folder that includes a photocopy of the original
article, including all of the photos, and a reduced-size set of plans.
It was easy to print copies of any article on my personalcomputer
printer. The plans are in the usual 8 x 10-inch format.
They can be taken to a photo facility, such as Kinko’s, enlarged, and
printed to your specific needs.
I got enthused as I went into each CD. I can’t wait to purchase
more discs for other interesting categories of model aviation. If you
decide to obtain some, please write in and let me hear your
comments.
Q90: “I like the electric motor speed controllers (ESCs) that allow
you to program in special features, like the voltage cutoff point,
motor timing, brake on or off, soft start, and other features.
“The only problem I find is that doing this programming requires
that you count blinking LEDs sometimes in a long sequence. This
approach is tedious to say the least. I heard recently that certain
vendors are now offering ESCs that can be programmed by your
home computer. Can you steer me in the right direction?”
A90: One ESC manufacturer is offering a computer-driven device
that allows you to program your electric motor speed controllers
more easily. This basically involves a special cable that you connect
between your ESC and a spare USB port on your PC. If you own a
laptop PC, you can do this programming at the flying field.
According to Bob and many others, this is
one of the best digital-readout tachometers.
It has proven to be accurate!
This is a “Basic” print screen of what you
see on your PC when you open the Castle
Creations PHX-Link software.
In addition to the cable, you will need
special software that really makes the
concept work. I recently picked up a PHXLink
cable and software from Castle
Creations (www.castlecreations.com), which
is intended to work with its Phoenix line of
brushless motor ESCs manufactured after
August 2003. The PHX-Link sells for
$24.95 and is compatible with operating
systems for Windows 98SE, 98ME, 2000, or
XP.
The software is simple to install on your
PC. It will let you view the current status
(settings) of your Phoenix ESC. Under the
“Basic” category you can set the low voltage
cutoff point for the type and number of cells
of your battery pack. It will also let you set
up the brake strength, throttle type, and softstarting
of the motor.
In the “Advanced” category you can set
such things as motor timing, current
limiting, and PWM (Pulse Width
Modulation) frequency. There are also plans
to provide software revisions and
enhancement via the Internet.
To use this “link,” download the Castle
Creations software into your PC. The
instructions are excellent. Connect the servo
cable coming from your Phoenix ESC into
the PHX-Link. Plug the cable with the Mini-
USB connector into the PHX-Link. The
other end of the cable goes into a spare USB
port on your PC.
The rest of the programming is easy to
do with your PC keyboard and mouse. Any
programming you input stays in the ESC
memory until you change or delete it.
As I was writing this, I also heard about
an ESC programming device that Hobby
Lobby will soon offer for its Jeti ESCs.
Instead of using a PC, there is a handheld
microprocessor device. From what I gather,
you move shorting plugs around to establish
your desired programming information, and
then this information is introduced into your
Jeti ESC at the press of a button.
I think variations in ESC programming
techniques will soon replace the older and
more tedious method with “blinking” LEDs.
Q91: “What kind of tachometer would you
recommend for general model use, be it
fueled or electric power?”
A91: The “best tachometer” theme was
recently kicked around on one of the
Internet model forums. After a week or so I
think I saw reference to almost every
tachometer ever offered by our hobby
industry to take motor/engine rpm readings
(such as how fast the propeller turns).
For years I have favored the TNC digital
readout/optical sensor tachometer that
retired IBM engineer Tony Criscimagna
(Woodstock, New York) designed. In 2003,
Tony sold the rights to his TNC tachometer
business to Skyborn Electronics of Dallas,
Texas.
The company’s Web page is
www.bktsi.com/. I’ve been able to call up
this site, but I can’t get any detailed
information about or prices for Skyborn’s
version of the TNC tachometer. Most of us
who are lucky enough to own one have
found it easy to lock on and extremely
accurate. I sincerely hope that this popular
product is still on the market.
Although I have no experience with it,
GloBee offers the IntelliTach digital
tachometer. The company’s Web site is
www.bestrc.com/globee/glbp0111.html.
I was attracted to this particular
tachometer because it has a memory circuit
that is capable of storing your last three rpm
readings. So rather than hurrying to write
down a reading, you simply push a button
and it is saved until after you have shut
down your engine.
I can’t attest to this product’s accuracy,
but that feature does seem desirable. If you
have used this GloBee tachometer, how
about writing in and telling us about it?
Q92: “I have two kind of related questions.
1) Assuming there is no ‘memory’ effect in
Ni-Cd or NiMH batteries used in RC
systems, why should they ever need to be
‘cycled’ or ‘discharged’? 2) What would
happen to RC system Ni-Cd or NiMH
batteries if they were charged at a 5C or
even 8C (very high) rate as opposed to the
recommended 2C or 3C fast charge rates?”
A92: I never really believed that the socalled
“memory” effect ever existed. It may
have in the older Ni-Cd batteries. It was
certainly never a problem with NiMH, and
it is definitely not a problem with new Li-
Poly batteries.
In my way of looking at it, “cycling” and
“discharging” are different functions.
“Cycling” to me is taking a battery down
and then recharging it. Quite often, and
especially when flying in contests, I use an
old motor to run down my battery pack. I let
it cool for a few minutes and then recharge
it. Doing that, I obtain the best possible
flights from that pack, from the first flight
of the day. When I “cycle” this way, I’m not
trying to determine the pack’s capacity.
NiMH packs have poor charge retention.
In a week’s time they might lose 20% of
their capacity. My first flight of the day
with NiMH cells is usually “soft.” The
model will be sluggish in flight, and the run
time will be less than normal. But after that
first fast charge at the field, subsequent
flights will be up to par (for that particular
pack).
“Discharge” to me is when I actually test
the battery for its capacity. I use any of the
testing devices on the market and apply a
known load, allowing the pack to go down
to approximately 1.0 volt per cell on Ni-
Cd/NiMH and 3.0 volts per cell on Li-Poly
batteries. The amount of the load and the
time it takes to get to those minimum
voltages allows you to calculate the
capacity in mAh.
I do this type of discharge testing on all
of my RC transmitters and four-cell receiver
(airborne) battery packs. I never cycle or
discharge-test the battery packs I use for
electric-powered flight because they are
essentially cycled (taken all the way down
and then fully recharged) on each flight.
Capacity can simply be judged by the
aircraft’s performance. If the model doesn’t
get off the ground or is sluggish in flight,
you either have poor capacity or you
improperly charged the battery.
Now to your question about charge rates
of 2C or 3C vs. 5C or 8C for RC-system
batteries. Most of the batteries supplied with
RC systems (transmitter and airborne packs)
are not intended for fast charging. It won’t
be stamped on the battery pack, but believe
me on that point.
Those batteries are generally the
cheapest available on the RC market. They
should be charged only at the overnight rate
(C/10), which you get when you use the
supplied RC-system dual-output, wall-plug
chargers. Feel free to charge overnight or
one, two, or four times a week, and still get
500-1,000 cycles from your packs.
Also consider that RC transmitters
usually have an internal fuse and relatively
lightweight wiring. When you go to 2C or
3C, you can easily burn out fuses and
wiring. Going to 5C or 8C, you could really
damage the equipment.
This all comes down to why you would
ever want to recharge your RC batteries at
2C, 3C, 5C, or 8C. Today you can purchase
AA-size NiMH cells with capacity ratings
of as much as 2,300 mAh. If you switch to
those types of cells, you could literally fly
all day. There should never be any need to
fast charge at the field.
These AA NiMH cells are inexpensive,
so having a second charged pack to
substitute during the day is a practical
solution. However, the only person who
would need that might be a Sailplane flier
who is going for the League of Silent Flight
Level V!
Regular electric-flight batteries are the
ones intended for fast charging. But even
then the charge currents should be limited to
2C (30 minutes) for NiMH, 3C (20 minutes)
for Ni-Cd, and 1C (one hour) for Li-Poly.
More than that is possible, but only by
sacrificing battery life. It simply isn’t worth
it. I hope this covers your questions. MA
AMA Academy of Model
Aeronautics
ARF Almost Ready to Fly
BEC Battery Eliminator Circuit
CAD computer-aided design
cc cubic centimeter
CD contest director or
compact disc
CG center of gravity
CL Control Line
cm centimeter
cu. in. cubic inch
DT dethermalizer
EPP (foam) expanded polypropylene
ESC Electronic Speed Control
FAI Fédération Aéronautique
Internationale
FCC Federal Communications
Commission
FF Free Flight
LCD Liquid Crystal Display
LE leading edge
LED light-emitting diode
Li-Poly Lithium Polymer
mA milliamperes
MA Model Aviation
mAh milliampere-hours
MHz megahertz
mph miles per hour
Nats AMA Nationals
Ni-Cd Nickel Cadmium
NiMH Nickel Metal Hydride
RC Radio Control
rpm revolutions per minute
RTF Ready to Fly
SASE self-addressed, stamped
envelope
SIG Special Interest Group
TE trailing edge
Edition: Model Aviation - 2005/02
Page Numbers: 144,145,146
Edition: Model Aviation - 2005/02
Page Numbers: 144,145,146
Bob Aberle
F r e q u e n t l y A s k e d Q u e s t i o n s
E-mail: [email protected]
A close-up of the Castle Creations PH-Link (for the Phoenix
ESCs), as part of the supplied programming cable.
Bob hasn’t tried this tachometer, but the feature that lets you
save the last three rpm readings is worth looking into.
Bob purchased these CDs from Tom Wilk, who offers a set of 16.
They cover almost every facet of aeromodeling.
THIS IS THE 11th monthly column in which you write in or Email
your questions, and I try to give you the best possible answers.
Each question is given a sequential number for identification
purposes. Because publication space is limited, part of each month’s
installment will appear here, and the columns in their entirety are
posted on the AMA Web site at www.modelaircraft.org/
mag/faq/index.asp.
Let’s get started!
Q89: “I’m beginning to realize that more and more magazines, the
AMA, and even private individuals are making available archives of
previously published model aircraft articles, plans, three-views,
photos, etc. Searching for this type of data can present problems at
times, depending on how the search program is organized.
“Keeping all of this in mind, could you recommend a good
starting point for me as I attempt to look up model aircraft designs of
yesterday?”
A89: AMA has established a digital archives of articles published in
MA from 1975 until 2000. (A notice concerning this service was
published in the June 2004 issue on page 36.)
In the Vintage Radio Control Society newsletter I noticed a
reference to a private archives service run by Tom Wilk of Duluth,
Minnesota. He offers a series of CDs that contains all kinds of
historical model-aircraft data. He currently has 16 CDs, and that
number is constantly growing.
You can obtain a complete listing of what Tom has available by
sending an E-mail to him at [email protected]. His mailing
address is 301 W. Redwing St., Duluth MN 55803. His telephone
number is (218) 724-0928. Each CD costs $10 including postage in
the US. Canadian and international orders can be filled at a slightly
higher cost.
I was curious, so I purchased three CDs: “SAM Legal Antique &
Old Timer F/F Gas” (#9), “SAM Legal Nostalgia F/F Gas” (#10),
and “Early Sport R/C” (#16).
I was surprised when I opened the first selection. Each CD has an
index identifying every article on that particular disc. Each model is
contained in a folder that includes a photocopy of the original
article, including all of the photos, and a reduced-size set of plans.
It was easy to print copies of any article on my personalcomputer
printer. The plans are in the usual 8 x 10-inch format.
They can be taken to a photo facility, such as Kinko’s, enlarged, and
printed to your specific needs.
I got enthused as I went into each CD. I can’t wait to purchase
more discs for other interesting categories of model aviation. If you
decide to obtain some, please write in and let me hear your
comments.
Q90: “I like the electric motor speed controllers (ESCs) that allow
you to program in special features, like the voltage cutoff point,
motor timing, brake on or off, soft start, and other features.
“The only problem I find is that doing this programming requires
that you count blinking LEDs sometimes in a long sequence. This
approach is tedious to say the least. I heard recently that certain
vendors are now offering ESCs that can be programmed by your
home computer. Can you steer me in the right direction?”
A90: One ESC manufacturer is offering a computer-driven device
that allows you to program your electric motor speed controllers
more easily. This basically involves a special cable that you connect
between your ESC and a spare USB port on your PC. If you own a
laptop PC, you can do this programming at the flying field.
According to Bob and many others, this is
one of the best digital-readout tachometers.
It has proven to be accurate!
This is a “Basic” print screen of what you
see on your PC when you open the Castle
Creations PHX-Link software.
In addition to the cable, you will need
special software that really makes the
concept work. I recently picked up a PHXLink
cable and software from Castle
Creations (www.castlecreations.com), which
is intended to work with its Phoenix line of
brushless motor ESCs manufactured after
August 2003. The PHX-Link sells for
$24.95 and is compatible with operating
systems for Windows 98SE, 98ME, 2000, or
XP.
The software is simple to install on your
PC. It will let you view the current status
(settings) of your Phoenix ESC. Under the
“Basic” category you can set the low voltage
cutoff point for the type and number of cells
of your battery pack. It will also let you set
up the brake strength, throttle type, and softstarting
of the motor.
In the “Advanced” category you can set
such things as motor timing, current
limiting, and PWM (Pulse Width
Modulation) frequency. There are also plans
to provide software revisions and
enhancement via the Internet.
To use this “link,” download the Castle
Creations software into your PC. The
instructions are excellent. Connect the servo
cable coming from your Phoenix ESC into
the PHX-Link. Plug the cable with the Mini-
USB connector into the PHX-Link. The
other end of the cable goes into a spare USB
port on your PC.
The rest of the programming is easy to
do with your PC keyboard and mouse. Any
programming you input stays in the ESC
memory until you change or delete it.
As I was writing this, I also heard about
an ESC programming device that Hobby
Lobby will soon offer for its Jeti ESCs.
Instead of using a PC, there is a handheld
microprocessor device. From what I gather,
you move shorting plugs around to establish
your desired programming information, and
then this information is introduced into your
Jeti ESC at the press of a button.
I think variations in ESC programming
techniques will soon replace the older and
more tedious method with “blinking” LEDs.
Q91: “What kind of tachometer would you
recommend for general model use, be it
fueled or electric power?”
A91: The “best tachometer” theme was
recently kicked around on one of the
Internet model forums. After a week or so I
think I saw reference to almost every
tachometer ever offered by our hobby
industry to take motor/engine rpm readings
(such as how fast the propeller turns).
For years I have favored the TNC digital
readout/optical sensor tachometer that
retired IBM engineer Tony Criscimagna
(Woodstock, New York) designed. In 2003,
Tony sold the rights to his TNC tachometer
business to Skyborn Electronics of Dallas,
Texas.
The company’s Web page is
www.bktsi.com/. I’ve been able to call up
this site, but I can’t get any detailed
information about or prices for Skyborn’s
version of the TNC tachometer. Most of us
who are lucky enough to own one have
found it easy to lock on and extremely
accurate. I sincerely hope that this popular
product is still on the market.
Although I have no experience with it,
GloBee offers the IntelliTach digital
tachometer. The company’s Web site is
www.bestrc.com/globee/glbp0111.html.
I was attracted to this particular
tachometer because it has a memory circuit
that is capable of storing your last three rpm
readings. So rather than hurrying to write
down a reading, you simply push a button
and it is saved until after you have shut
down your engine.
I can’t attest to this product’s accuracy,
but that feature does seem desirable. If you
have used this GloBee tachometer, how
about writing in and telling us about it?
Q92: “I have two kind of related questions.
1) Assuming there is no ‘memory’ effect in
Ni-Cd or NiMH batteries used in RC
systems, why should they ever need to be
‘cycled’ or ‘discharged’? 2) What would
happen to RC system Ni-Cd or NiMH
batteries if they were charged at a 5C or
even 8C (very high) rate as opposed to the
recommended 2C or 3C fast charge rates?”
A92: I never really believed that the socalled
“memory” effect ever existed. It may
have in the older Ni-Cd batteries. It was
certainly never a problem with NiMH, and
it is definitely not a problem with new Li-
Poly batteries.
In my way of looking at it, “cycling” and
“discharging” are different functions.
“Cycling” to me is taking a battery down
and then recharging it. Quite often, and
especially when flying in contests, I use an
old motor to run down my battery pack. I let
it cool for a few minutes and then recharge
it. Doing that, I obtain the best possible
flights from that pack, from the first flight
of the day. When I “cycle” this way, I’m not
trying to determine the pack’s capacity.
NiMH packs have poor charge retention.
In a week’s time they might lose 20% of
their capacity. My first flight of the day
with NiMH cells is usually “soft.” The
model will be sluggish in flight, and the run
time will be less than normal. But after that
first fast charge at the field, subsequent
flights will be up to par (for that particular
pack).
“Discharge” to me is when I actually test
the battery for its capacity. I use any of the
testing devices on the market and apply a
known load, allowing the pack to go down
to approximately 1.0 volt per cell on Ni-
Cd/NiMH and 3.0 volts per cell on Li-Poly
batteries. The amount of the load and the
time it takes to get to those minimum
voltages allows you to calculate the
capacity in mAh.
I do this type of discharge testing on all
of my RC transmitters and four-cell receiver
(airborne) battery packs. I never cycle or
discharge-test the battery packs I use for
electric-powered flight because they are
essentially cycled (taken all the way down
and then fully recharged) on each flight.
Capacity can simply be judged by the
aircraft’s performance. If the model doesn’t
get off the ground or is sluggish in flight,
you either have poor capacity or you
improperly charged the battery.
Now to your question about charge rates
of 2C or 3C vs. 5C or 8C for RC-system
batteries. Most of the batteries supplied with
RC systems (transmitter and airborne packs)
are not intended for fast charging. It won’t
be stamped on the battery pack, but believe
me on that point.
Those batteries are generally the
cheapest available on the RC market. They
should be charged only at the overnight rate
(C/10), which you get when you use the
supplied RC-system dual-output, wall-plug
chargers. Feel free to charge overnight or
one, two, or four times a week, and still get
500-1,000 cycles from your packs.
Also consider that RC transmitters
usually have an internal fuse and relatively
lightweight wiring. When you go to 2C or
3C, you can easily burn out fuses and
wiring. Going to 5C or 8C, you could really
damage the equipment.
This all comes down to why you would
ever want to recharge your RC batteries at
2C, 3C, 5C, or 8C. Today you can purchase
AA-size NiMH cells with capacity ratings
of as much as 2,300 mAh. If you switch to
those types of cells, you could literally fly
all day. There should never be any need to
fast charge at the field.
These AA NiMH cells are inexpensive,
so having a second charged pack to
substitute during the day is a practical
solution. However, the only person who
would need that might be a Sailplane flier
who is going for the League of Silent Flight
Level V!
Regular electric-flight batteries are the
ones intended for fast charging. But even
then the charge currents should be limited to
2C (30 minutes) for NiMH, 3C (20 minutes)
for Ni-Cd, and 1C (one hour) for Li-Poly.
More than that is possible, but only by
sacrificing battery life. It simply isn’t worth
it. I hope this covers your questions. MA
AMA Academy of Model
Aeronautics
ARF Almost Ready to Fly
BEC Battery Eliminator Circuit
CAD computer-aided design
cc cubic centimeter
CD contest director or
compact disc
CG center of gravity
CL Control Line
cm centimeter
cu. in. cubic inch
DT dethermalizer
EPP (foam) expanded polypropylene
ESC Electronic Speed Control
FAI Fédération Aéronautique
Internationale
FCC Federal Communications
Commission
FF Free Flight
LCD Liquid Crystal Display
LE leading edge
LED light-emitting diode
Li-Poly Lithium Polymer
mA milliamperes
MA Model Aviation
mAh milliampere-hours
MHz megahertz
mph miles per hour
Nats AMA Nationals
Ni-Cd Nickel Cadmium
NiMH Nickel Metal Hydride
RC Radio Control
rpm revolutions per minute
RTF Ready to Fly
SASE self-addressed, stamped
envelope
SIG Special Interest Group
TE trailing edge
Edition: Model Aviation - 2005/02
Page Numbers: 144,145,146
Bob Aberle
F r e q u e n t l y A s k e d Q u e s t i o n s
E-mail: [email protected]
A close-up of the Castle Creations PH-Link (for the Phoenix
ESCs), as part of the supplied programming cable.
Bob hasn’t tried this tachometer, but the feature that lets you
save the last three rpm readings is worth looking into.
Bob purchased these CDs from Tom Wilk, who offers a set of 16.
They cover almost every facet of aeromodeling.
THIS IS THE 11th monthly column in which you write in or Email
your questions, and I try to give you the best possible answers.
Each question is given a sequential number for identification
purposes. Because publication space is limited, part of each month’s
installment will appear here, and the columns in their entirety are
posted on the AMA Web site at www.modelaircraft.org/
mag/faq/index.asp.
Let’s get started!
Q89: “I’m beginning to realize that more and more magazines, the
AMA, and even private individuals are making available archives of
previously published model aircraft articles, plans, three-views,
photos, etc. Searching for this type of data can present problems at
times, depending on how the search program is organized.
“Keeping all of this in mind, could you recommend a good
starting point for me as I attempt to look up model aircraft designs of
yesterday?”
A89: AMA has established a digital archives of articles published in
MA from 1975 until 2000. (A notice concerning this service was
published in the June 2004 issue on page 36.)
In the Vintage Radio Control Society newsletter I noticed a
reference to a private archives service run by Tom Wilk of Duluth,
Minnesota. He offers a series of CDs that contains all kinds of
historical model-aircraft data. He currently has 16 CDs, and that
number is constantly growing.
You can obtain a complete listing of what Tom has available by
sending an E-mail to him at [email protected]. His mailing
address is 301 W. Redwing St., Duluth MN 55803. His telephone
number is (218) 724-0928. Each CD costs $10 including postage in
the US. Canadian and international orders can be filled at a slightly
higher cost.
I was curious, so I purchased three CDs: “SAM Legal Antique &
Old Timer F/F Gas” (#9), “SAM Legal Nostalgia F/F Gas” (#10),
and “Early Sport R/C” (#16).
I was surprised when I opened the first selection. Each CD has an
index identifying every article on that particular disc. Each model is
contained in a folder that includes a photocopy of the original
article, including all of the photos, and a reduced-size set of plans.
It was easy to print copies of any article on my personalcomputer
printer. The plans are in the usual 8 x 10-inch format.
They can be taken to a photo facility, such as Kinko’s, enlarged, and
printed to your specific needs.
I got enthused as I went into each CD. I can’t wait to purchase
more discs for other interesting categories of model aviation. If you
decide to obtain some, please write in and let me hear your
comments.
Q90: “I like the electric motor speed controllers (ESCs) that allow
you to program in special features, like the voltage cutoff point,
motor timing, brake on or off, soft start, and other features.
“The only problem I find is that doing this programming requires
that you count blinking LEDs sometimes in a long sequence. This
approach is tedious to say the least. I heard recently that certain
vendors are now offering ESCs that can be programmed by your
home computer. Can you steer me in the right direction?”
A90: One ESC manufacturer is offering a computer-driven device
that allows you to program your electric motor speed controllers
more easily. This basically involves a special cable that you connect
between your ESC and a spare USB port on your PC. If you own a
laptop PC, you can do this programming at the flying field.
According to Bob and many others, this is
one of the best digital-readout tachometers.
It has proven to be accurate!
This is a “Basic” print screen of what you
see on your PC when you open the Castle
Creations PHX-Link software.
In addition to the cable, you will need
special software that really makes the
concept work. I recently picked up a PHXLink
cable and software from Castle
Creations (www.castlecreations.com), which
is intended to work with its Phoenix line of
brushless motor ESCs manufactured after
August 2003. The PHX-Link sells for
$24.95 and is compatible with operating
systems for Windows 98SE, 98ME, 2000, or
XP.
The software is simple to install on your
PC. It will let you view the current status
(settings) of your Phoenix ESC. Under the
“Basic” category you can set the low voltage
cutoff point for the type and number of cells
of your battery pack. It will also let you set
up the brake strength, throttle type, and softstarting
of the motor.
In the “Advanced” category you can set
such things as motor timing, current
limiting, and PWM (Pulse Width
Modulation) frequency. There are also plans
to provide software revisions and
enhancement via the Internet.
To use this “link,” download the Castle
Creations software into your PC. The
instructions are excellent. Connect the servo
cable coming from your Phoenix ESC into
the PHX-Link. Plug the cable with the Mini-
USB connector into the PHX-Link. The
other end of the cable goes into a spare USB
port on your PC.
The rest of the programming is easy to
do with your PC keyboard and mouse. Any
programming you input stays in the ESC
memory until you change or delete it.
As I was writing this, I also heard about
an ESC programming device that Hobby
Lobby will soon offer for its Jeti ESCs.
Instead of using a PC, there is a handheld
microprocessor device. From what I gather,
you move shorting plugs around to establish
your desired programming information, and
then this information is introduced into your
Jeti ESC at the press of a button.
I think variations in ESC programming
techniques will soon replace the older and
more tedious method with “blinking” LEDs.
Q91: “What kind of tachometer would you
recommend for general model use, be it
fueled or electric power?”
A91: The “best tachometer” theme was
recently kicked around on one of the
Internet model forums. After a week or so I
think I saw reference to almost every
tachometer ever offered by our hobby
industry to take motor/engine rpm readings
(such as how fast the propeller turns).
For years I have favored the TNC digital
readout/optical sensor tachometer that
retired IBM engineer Tony Criscimagna
(Woodstock, New York) designed. In 2003,
Tony sold the rights to his TNC tachometer
business to Skyborn Electronics of Dallas,
Texas.
The company’s Web page is
www.bktsi.com/. I’ve been able to call up
this site, but I can’t get any detailed
information about or prices for Skyborn’s
version of the TNC tachometer. Most of us
who are lucky enough to own one have
found it easy to lock on and extremely
accurate. I sincerely hope that this popular
product is still on the market.
Although I have no experience with it,
GloBee offers the IntelliTach digital
tachometer. The company’s Web site is
www.bestrc.com/globee/glbp0111.html.
I was attracted to this particular
tachometer because it has a memory circuit
that is capable of storing your last three rpm
readings. So rather than hurrying to write
down a reading, you simply push a button
and it is saved until after you have shut
down your engine.
I can’t attest to this product’s accuracy,
but that feature does seem desirable. If you
have used this GloBee tachometer, how
about writing in and telling us about it?
Q92: “I have two kind of related questions.
1) Assuming there is no ‘memory’ effect in
Ni-Cd or NiMH batteries used in RC
systems, why should they ever need to be
‘cycled’ or ‘discharged’? 2) What would
happen to RC system Ni-Cd or NiMH
batteries if they were charged at a 5C or
even 8C (very high) rate as opposed to the
recommended 2C or 3C fast charge rates?”
A92: I never really believed that the socalled
“memory” effect ever existed. It may
have in the older Ni-Cd batteries. It was
certainly never a problem with NiMH, and
it is definitely not a problem with new Li-
Poly batteries.
In my way of looking at it, “cycling” and
“discharging” are different functions.
“Cycling” to me is taking a battery down
and then recharging it. Quite often, and
especially when flying in contests, I use an
old motor to run down my battery pack. I let
it cool for a few minutes and then recharge
it. Doing that, I obtain the best possible
flights from that pack, from the first flight
of the day. When I “cycle” this way, I’m not
trying to determine the pack’s capacity.
NiMH packs have poor charge retention.
In a week’s time they might lose 20% of
their capacity. My first flight of the day
with NiMH cells is usually “soft.” The
model will be sluggish in flight, and the run
time will be less than normal. But after that
first fast charge at the field, subsequent
flights will be up to par (for that particular
pack).
“Discharge” to me is when I actually test
the battery for its capacity. I use any of the
testing devices on the market and apply a
known load, allowing the pack to go down
to approximately 1.0 volt per cell on Ni-
Cd/NiMH and 3.0 volts per cell on Li-Poly
batteries. The amount of the load and the
time it takes to get to those minimum
voltages allows you to calculate the
capacity in mAh.
I do this type of discharge testing on all
of my RC transmitters and four-cell receiver
(airborne) battery packs. I never cycle or
discharge-test the battery packs I use for
electric-powered flight because they are
essentially cycled (taken all the way down
and then fully recharged) on each flight.
Capacity can simply be judged by the
aircraft’s performance. If the model doesn’t
get off the ground or is sluggish in flight,
you either have poor capacity or you
improperly charged the battery.
Now to your question about charge rates
of 2C or 3C vs. 5C or 8C for RC-system
batteries. Most of the batteries supplied with
RC systems (transmitter and airborne packs)
are not intended for fast charging. It won’t
be stamped on the battery pack, but believe
me on that point.
Those batteries are generally the
cheapest available on the RC market. They
should be charged only at the overnight rate
(C/10), which you get when you use the
supplied RC-system dual-output, wall-plug
chargers. Feel free to charge overnight or
one, two, or four times a week, and still get
500-1,000 cycles from your packs.
Also consider that RC transmitters
usually have an internal fuse and relatively
lightweight wiring. When you go to 2C or
3C, you can easily burn out fuses and
wiring. Going to 5C or 8C, you could really
damage the equipment.
This all comes down to why you would
ever want to recharge your RC batteries at
2C, 3C, 5C, or 8C. Today you can purchase
AA-size NiMH cells with capacity ratings
of as much as 2,300 mAh. If you switch to
those types of cells, you could literally fly
all day. There should never be any need to
fast charge at the field.
These AA NiMH cells are inexpensive,
so having a second charged pack to
substitute during the day is a practical
solution. However, the only person who
would need that might be a Sailplane flier
who is going for the League of Silent Flight
Level V!
Regular electric-flight batteries are the
ones intended for fast charging. But even
then the charge currents should be limited to
2C (30 minutes) for NiMH, 3C (20 minutes)
for Ni-Cd, and 1C (one hour) for Li-Poly.
More than that is possible, but only by
sacrificing battery life. It simply isn’t worth
it. I hope this covers your questions. MA
AMA Academy of Model
Aeronautics
ARF Almost Ready to Fly
BEC Battery Eliminator Circuit
CAD computer-aided design
cc cubic centimeter
CD contest director or
compact disc
CG center of gravity
CL Control Line
cm centimeter
cu. in. cubic inch
DT dethermalizer
EPP (foam) expanded polypropylene
ESC Electronic Speed Control
FAI Fédération Aéronautique
Internationale
FCC Federal Communications
Commission
FF Free Flight
LCD Liquid Crystal Display
LE leading edge
LED light-emitting diode
Li-Poly Lithium Polymer
mA milliamperes
MA Model Aviation
mAh milliampere-hours
MHz megahertz
mph miles per hour
Nats AMA Nationals
Ni-Cd Nickel Cadmium
NiMH Nickel Metal Hydride
RC Radio Control
rpm revolutions per minute
RTF Ready to Fly
SASE self-addressed, stamped
envelope
SIG Special Interest Group
TE trailing edge