THIS COLUMN INCLUDES one meet announcement, new Ecatalog
info, comments on E-suppliers, an anniversary story,
speculation about Lithium batteries, some reader input, and a new
product.
John Jenks of the South Jersey Silent Flyers sent information
regarding a series of club-sponsored meets this season. Unfortunately,
the info came too late for me to share most of it and barely in time for
the RC Electrics meet on October 10. (Ya gotta get the stuff to me
early!)
The meet will have plaques for several events, including pylon,
limbo, and AULD (All-Up/Last-Down). You can get more details from
John at (856) 983-7024 or from Bob Bunting at (856) 786-0798. You
can get directions to the Marlton, New Jersey, field at www.sjsf.org.
I buy most of my supplies at a local hobby shop because it’s close and
because I believe in supporting my local business community. This
often costs me a bit more, but I feel that it’s worth it. However, I also
purchase some mail-order E-stuff.
One of my favorite mail-order suppliers is New Creations R/C
Bob Kopski, 25 West End Dr., Lansdale PA 19446
RADIO CONTROL ELECTRICS
AXI Outrunner motor mounted in REVOLT! and ready to test-fly.
Ample room is left over in motor-compartment area.
West Mountain Radio CBA interfaced with Bob’s personal
computer via USB cable. A seven-cell KAN 950 pack is under test.
(Box 496, Willis TX 77378; Tel.: [936] 856-4630; Web site:
www.newcreations-rc.com). I’ve been buying from this company for
years. These knowledgeable people are a pleasure to talk to, and their
service is super! Kirk Massey—head aeromodeler at New Creations
R/C—tells me he’s updating the catalog, and it should be available by
the time you read this. I want one of those!
I’ve had great experiences with other suppliers, large and small. A
good experience is the norm. But I’ve learned that there are the other
kind as well. Paradoxically, I had a bad encounter with a high-profile
operation. This supplier presents a glowing image with its full-page
color print advertising and its inviting Web site. But for me, that’s
about all this vendor has to offer.
The online ordering process was misleading. “Out of stock” items
were not identified (most companies do identify them), but my credit
card was quickly charged anyway (most companies don’t do that). I’ve
since paid my credit card bill, but I still don’t have the stuff I paid for
(weeks waiting), and I’ve not been able to get a believable delivery
date. Another goodie was that the customer service E-mail address
didn’t work.
There’s more bad stuff, but I’ll end this by suggesting that you
place your first order with any new-to-you supplier by telephone. It’s
easier to know what you’re dealing with, and you can better determine
if you want to give your card number out. Caveat emptor.
This issue marks the 10th anniversary of my Revolt! construction
article being published in MA. The now-obscure design has since
accrued a long and unusual flight log.
Revolt! was conceived as a test vehicle for E-stuff. It is otherwise a
ho hum-looking cabin-type design, suggesting “boring” to many. Since
it was intended to “carry stuff,” it has large cabin and motor
compartments, 600 square inches of high-lift wing section, and is a
basically stable design overall. Once trimmed, it is perfectly capable of
stable “free flight” performance.
This aircraft has served its intended purpose well throughout the
decade, and it still does, although to a much lesser degree than in years
past. Still, of the many models in my hangar, it’s the most flown.
As a power-system test vehicle, Revolt! has been flown with feeble
600-size direct-drive can motors on seven cells up to geared
AstroFlight 40 Cobalts on 21 cells. (Yes, that is all in one airplane!)
Other power systems included a wide variety of motors, such as
early Keller and Robbe products, “car motor”-
based products, nearly all classic AstroFlight
products, and contemporary brushless stuff. A
photo shows a decade-old Revolt! set up to try
an AXI Outrunner motor, which is new as I
write this.
Unlike all previous installations, the AXI
Outrunner presented a mounting challenge.
The other motors—geared or not—were
mounted on the accommodating “VEE” block
mount system designed into Revolt! However,
the AXI cannot be mounted in a VEE block;
the motor housing rotates!
I decided to attach a removable 1⁄8 birchplywood
nose plate to Revolt!, and then fix the
AXI front-end bell behind that. If this suggests
bad planning to you, please remember that
Outrunners did not exist when Revolt! was
designed!
In addition to serving as a power-system
test bed, Revolt! has been pressed into service
flight-testing ESCs and radio equipment, has
had “glitch-counting” and telemetry
equipment installed, and several readers have
installed cameras.
But beyond all that, Revolt! has shown its
abilities as an unplanned basic trainer for some
readers. Through the years I have routinely
handed the sticks of this docile craft to youthful
and senior bystanders and talked them through
Shown is the CBA display screen. Here it is reporting 0.72 ampere-hours capacity for
old KAN 950 seven-cell pack under 5-amp test current drain.
the air—knowing that the airplane was forgiving.
Thus this simplistic three-channel E-aero design has become less of
a test resource and much more of a regular companion through the
years. I typically take two or three E-airplanes to the field each time I
go, and a Revolt! is usually one of them. It’s my relaxing “comfort”
airplane—it just feels good—with its
normally installed 15G/12-cell system.
Out of curiosity and for purposes here, I
just reviewed my Revolt! flight logs to date
(July 2, 2004), beginning with the first on
April 10, 1993. The tally: 2,110 flights! How
many flights do you have on your favorite
model?
I’m sure that by now, nearly all Eaeromodelers
are using, or are at least aware
of, today’s popular battery technology:
Lithium-Polymer, more commonly known as
“Li-Poly.” Li-Poly has hit the market in more
of a “flash flood” fashion than past battery
products have. It seems as though each month
more companies and product labels are added
to the already large supplier list. And the
warnings and cautions about the use and
abuse of Li-Poly continue.
With the product itself, most Eaeromodelers
are probably also familiar with
the safety “dos” and “don’ts,” so I’m not
going to belabor the detail here. Rather, with
the continuing strong handling cautions mixed
with emerging tales of woe, I cannot help but
wonder if this product was not introduced
prematurely.
Noting that there are no similar cautions
and costly losses associated with other
Lithium-powered consumer applications, such
as cell phones, pagers, laptops, etc., why is
our E-aeromodeling application so different?
I think the answer lies with the consumer
products having built-in protection devices,
dedicated (inflexible) chargers, and unique
application interfaces that protect the user—
from himself or herself. You can’t easily use
the consumer stuff “wrong.”
Our stuff, having essentially no
“containment” as in the preceding, does not
have protections built in or dedicated
interfaces. In effect, safe handling lies totally
in our hands, so it is not always in a firm grip.
I have a feeling that this will eventually
change—out of necessity.
I might imagine a standardized Li-Poly
“hobby-use interface,” bounding charging and
application variables. A possible form of
this—perhaps instead of or in addition to
electronics built into each pack—would be
standardized connectors. I could imagine
multipin interfaces with connections to each
cell of a pack assembly and a “standard
specification” charger interface emerging. I’m
sure there must be other options as well. I’m
just guessing.
Whatever the case, it’s hard to imagine the
risks and losses associated with present-day
Li-Poly continuing without eventual impact
on all aeromodelers, such as increasing
insurance premiums. All reader comment on
this topic is welcome.
While on the subject of Li-Poly, the
opening sentence of the Universal Slow
Charger article published in the September
2000 MA reads: “The Universal Slow Charger
is a uniquely capable, versatile, flexible
charger design that can accommodate all
aeromodeling rechargeables I know of, and
more.”
This was true at the time, but it is no
longer true. Do not use the Universal Slow
Charger with Li-Poly batteries!
Several readers reacted to the August
column’s discussion about switches used in
Electrics. Surprisingly, one recurring input I
received was concerning the use of small
arming toggle switches with brushless
systems. In that column I described how
such switches can be instantly destroyed by
the presence of large electrolytic capacitors
on the power-input connections of most
brushless ESCs.
Several readers independently suggested
the same solution to this problem. Although
the specifics varied a bit among them, the
basic idea was to install a second switch in
parallel with the first—except the second
would have in series with it a small-value
resistor.
The idea is to close this second path first,
allowing the ESC input capacitors to safely
charge up to battery voltage via the resistor
(takes less than a second), and then close the
“real” arming switch. This way, the latter is
protected from the huge surge of current
upon initial closure because it’s closing on
an already charged capacitor.
I agree that this is a sound approach to
the problem, but I’d prefer not to have to
mount a second switch. Nor do I like having
to remember to sequence the two-switch
power-up operation. So I’m still looking for
a simpler approach—perhaps an impossible
quest. Meanwhile, thanks to those who
picked up on the topic and reacted with
workable inputs for us all. (I’m now looking
at a Revolt! to test this in!)
West Mountain Radio (18 Sheehan Ave.,
Norwalk CT 06854; Tel.: [203] 853-8080;
Web site: www.westmountainradio.com) is
a popular supplier of amateur-radio-related
equipment. However, the guys at the
company are also active aeromodelers.
Since both hobbies use rechargeable
batteries, it’s no surprise to see the
company introduce a related new product:
the Computerized Battery Analyzer, or
CBA.
This easy-to-use device interfaces with a
personal computer via a USB port and is
powered from that port as well. With it, you
can easily keep tabs on the health of all your
rechargeables during their lifetime.
The associated software allows the user
to enter varied test parameters including cell
count (1-48 volts), battery type, discharge
current, cutoff voltage, etc. Once discharge
is initiated, the program presents a discharge
screen, as shown for a seven-cell 950 KAN
NiMH pack. The vertical scale is for battery
voltage and the horizontal axis displays
ampere-hours. The latter display “grows” as
test time accumulates.
I have not tried all of the features yet, but
the software allows battery-test naming and
permits “overlays” of more than one battery
rundown for comparison purposes. Other
features include temperature monitoring.
The CBA covers all of our common
rechargeable battery types—including Li-
Poly. This device is not a “cycler,” meaning
that it has no charging function.
I will have more in the future, but in the
meantime you can check out the CBA on
the West Mountain Radio Web site. Then
put it on your “seasonal” wish list!
West Mountain Radio also offers
Anderson Power Poles at great prices—such
as 25 pair for $19.95. Other quantities are
available.
Thus ends another installment. My next RC
Electrics column will be in the January
2005 issue; December is the dedicated Nats
issue.
Please enclose an SASE with all
correspondence for which you’d like a
reply. Everyone so doing does get one. And
do enjoy continued happy E-landings
throughout the fall and winter—noting that
there is no associated residue of cold,
semisolid glop to clean! MA
Edition: Model Aviation - 2004/11
Page Numbers: 102,104,106
Edition: Model Aviation - 2004/11
Page Numbers: 102,104,106
THIS COLUMN INCLUDES one meet announcement, new Ecatalog
info, comments on E-suppliers, an anniversary story,
speculation about Lithium batteries, some reader input, and a new
product.
John Jenks of the South Jersey Silent Flyers sent information
regarding a series of club-sponsored meets this season. Unfortunately,
the info came too late for me to share most of it and barely in time for
the RC Electrics meet on October 10. (Ya gotta get the stuff to me
early!)
The meet will have plaques for several events, including pylon,
limbo, and AULD (All-Up/Last-Down). You can get more details from
John at (856) 983-7024 or from Bob Bunting at (856) 786-0798. You
can get directions to the Marlton, New Jersey, field at www.sjsf.org.
I buy most of my supplies at a local hobby shop because it’s close and
because I believe in supporting my local business community. This
often costs me a bit more, but I feel that it’s worth it. However, I also
purchase some mail-order E-stuff.
One of my favorite mail-order suppliers is New Creations R/C
Bob Kopski, 25 West End Dr., Lansdale PA 19446
RADIO CONTROL ELECTRICS
AXI Outrunner motor mounted in REVOLT! and ready to test-fly.
Ample room is left over in motor-compartment area.
West Mountain Radio CBA interfaced with Bob’s personal
computer via USB cable. A seven-cell KAN 950 pack is under test.
(Box 496, Willis TX 77378; Tel.: [936] 856-4630; Web site:
www.newcreations-rc.com). I’ve been buying from this company for
years. These knowledgeable people are a pleasure to talk to, and their
service is super! Kirk Massey—head aeromodeler at New Creations
R/C—tells me he’s updating the catalog, and it should be available by
the time you read this. I want one of those!
I’ve had great experiences with other suppliers, large and small. A
good experience is the norm. But I’ve learned that there are the other
kind as well. Paradoxically, I had a bad encounter with a high-profile
operation. This supplier presents a glowing image with its full-page
color print advertising and its inviting Web site. But for me, that’s
about all this vendor has to offer.
The online ordering process was misleading. “Out of stock” items
were not identified (most companies do identify them), but my credit
card was quickly charged anyway (most companies don’t do that). I’ve
since paid my credit card bill, but I still don’t have the stuff I paid for
(weeks waiting), and I’ve not been able to get a believable delivery
date. Another goodie was that the customer service E-mail address
didn’t work.
There’s more bad stuff, but I’ll end this by suggesting that you
place your first order with any new-to-you supplier by telephone. It’s
easier to know what you’re dealing with, and you can better determine
if you want to give your card number out. Caveat emptor.
This issue marks the 10th anniversary of my Revolt! construction
article being published in MA. The now-obscure design has since
accrued a long and unusual flight log.
Revolt! was conceived as a test vehicle for E-stuff. It is otherwise a
ho hum-looking cabin-type design, suggesting “boring” to many. Since
it was intended to “carry stuff,” it has large cabin and motor
compartments, 600 square inches of high-lift wing section, and is a
basically stable design overall. Once trimmed, it is perfectly capable of
stable “free flight” performance.
This aircraft has served its intended purpose well throughout the
decade, and it still does, although to a much lesser degree than in years
past. Still, of the many models in my hangar, it’s the most flown.
As a power-system test vehicle, Revolt! has been flown with feeble
600-size direct-drive can motors on seven cells up to geared
AstroFlight 40 Cobalts on 21 cells. (Yes, that is all in one airplane!)
Other power systems included a wide variety of motors, such as
early Keller and Robbe products, “car motor”-
based products, nearly all classic AstroFlight
products, and contemporary brushless stuff. A
photo shows a decade-old Revolt! set up to try
an AXI Outrunner motor, which is new as I
write this.
Unlike all previous installations, the AXI
Outrunner presented a mounting challenge.
The other motors—geared or not—were
mounted on the accommodating “VEE” block
mount system designed into Revolt! However,
the AXI cannot be mounted in a VEE block;
the motor housing rotates!
I decided to attach a removable 1⁄8 birchplywood
nose plate to Revolt!, and then fix the
AXI front-end bell behind that. If this suggests
bad planning to you, please remember that
Outrunners did not exist when Revolt! was
designed!
In addition to serving as a power-system
test bed, Revolt! has been pressed into service
flight-testing ESCs and radio equipment, has
had “glitch-counting” and telemetry
equipment installed, and several readers have
installed cameras.
But beyond all that, Revolt! has shown its
abilities as an unplanned basic trainer for some
readers. Through the years I have routinely
handed the sticks of this docile craft to youthful
and senior bystanders and talked them through
Shown is the CBA display screen. Here it is reporting 0.72 ampere-hours capacity for
old KAN 950 seven-cell pack under 5-amp test current drain.
the air—knowing that the airplane was forgiving.
Thus this simplistic three-channel E-aero design has become less of
a test resource and much more of a regular companion through the
years. I typically take two or three E-airplanes to the field each time I
go, and a Revolt! is usually one of them. It’s my relaxing “comfort”
airplane—it just feels good—with its
normally installed 15G/12-cell system.
Out of curiosity and for purposes here, I
just reviewed my Revolt! flight logs to date
(July 2, 2004), beginning with the first on
April 10, 1993. The tally: 2,110 flights! How
many flights do you have on your favorite
model?
I’m sure that by now, nearly all Eaeromodelers
are using, or are at least aware
of, today’s popular battery technology:
Lithium-Polymer, more commonly known as
“Li-Poly.” Li-Poly has hit the market in more
of a “flash flood” fashion than past battery
products have. It seems as though each month
more companies and product labels are added
to the already large supplier list. And the
warnings and cautions about the use and
abuse of Li-Poly continue.
With the product itself, most Eaeromodelers
are probably also familiar with
the safety “dos” and “don’ts,” so I’m not
going to belabor the detail here. Rather, with
the continuing strong handling cautions mixed
with emerging tales of woe, I cannot help but
wonder if this product was not introduced
prematurely.
Noting that there are no similar cautions
and costly losses associated with other
Lithium-powered consumer applications, such
as cell phones, pagers, laptops, etc., why is
our E-aeromodeling application so different?
I think the answer lies with the consumer
products having built-in protection devices,
dedicated (inflexible) chargers, and unique
application interfaces that protect the user—
from himself or herself. You can’t easily use
the consumer stuff “wrong.”
Our stuff, having essentially no
“containment” as in the preceding, does not
have protections built in or dedicated
interfaces. In effect, safe handling lies totally
in our hands, so it is not always in a firm grip.
I have a feeling that this will eventually
change—out of necessity.
I might imagine a standardized Li-Poly
“hobby-use interface,” bounding charging and
application variables. A possible form of
this—perhaps instead of or in addition to
electronics built into each pack—would be
standardized connectors. I could imagine
multipin interfaces with connections to each
cell of a pack assembly and a “standard
specification” charger interface emerging. I’m
sure there must be other options as well. I’m
just guessing.
Whatever the case, it’s hard to imagine the
risks and losses associated with present-day
Li-Poly continuing without eventual impact
on all aeromodelers, such as increasing
insurance premiums. All reader comment on
this topic is welcome.
While on the subject of Li-Poly, the
opening sentence of the Universal Slow
Charger article published in the September
2000 MA reads: “The Universal Slow Charger
is a uniquely capable, versatile, flexible
charger design that can accommodate all
aeromodeling rechargeables I know of, and
more.”
This was true at the time, but it is no
longer true. Do not use the Universal Slow
Charger with Li-Poly batteries!
Several readers reacted to the August
column’s discussion about switches used in
Electrics. Surprisingly, one recurring input I
received was concerning the use of small
arming toggle switches with brushless
systems. In that column I described how
such switches can be instantly destroyed by
the presence of large electrolytic capacitors
on the power-input connections of most
brushless ESCs.
Several readers independently suggested
the same solution to this problem. Although
the specifics varied a bit among them, the
basic idea was to install a second switch in
parallel with the first—except the second
would have in series with it a small-value
resistor.
The idea is to close this second path first,
allowing the ESC input capacitors to safely
charge up to battery voltage via the resistor
(takes less than a second), and then close the
“real” arming switch. This way, the latter is
protected from the huge surge of current
upon initial closure because it’s closing on
an already charged capacitor.
I agree that this is a sound approach to
the problem, but I’d prefer not to have to
mount a second switch. Nor do I like having
to remember to sequence the two-switch
power-up operation. So I’m still looking for
a simpler approach—perhaps an impossible
quest. Meanwhile, thanks to those who
picked up on the topic and reacted with
workable inputs for us all. (I’m now looking
at a Revolt! to test this in!)
West Mountain Radio (18 Sheehan Ave.,
Norwalk CT 06854; Tel.: [203] 853-8080;
Web site: www.westmountainradio.com) is
a popular supplier of amateur-radio-related
equipment. However, the guys at the
company are also active aeromodelers.
Since both hobbies use rechargeable
batteries, it’s no surprise to see the
company introduce a related new product:
the Computerized Battery Analyzer, or
CBA.
This easy-to-use device interfaces with a
personal computer via a USB port and is
powered from that port as well. With it, you
can easily keep tabs on the health of all your
rechargeables during their lifetime.
The associated software allows the user
to enter varied test parameters including cell
count (1-48 volts), battery type, discharge
current, cutoff voltage, etc. Once discharge
is initiated, the program presents a discharge
screen, as shown for a seven-cell 950 KAN
NiMH pack. The vertical scale is for battery
voltage and the horizontal axis displays
ampere-hours. The latter display “grows” as
test time accumulates.
I have not tried all of the features yet, but
the software allows battery-test naming and
permits “overlays” of more than one battery
rundown for comparison purposes. Other
features include temperature monitoring.
The CBA covers all of our common
rechargeable battery types—including Li-
Poly. This device is not a “cycler,” meaning
that it has no charging function.
I will have more in the future, but in the
meantime you can check out the CBA on
the West Mountain Radio Web site. Then
put it on your “seasonal” wish list!
West Mountain Radio also offers
Anderson Power Poles at great prices—such
as 25 pair for $19.95. Other quantities are
available.
Thus ends another installment. My next RC
Electrics column will be in the January
2005 issue; December is the dedicated Nats
issue.
Please enclose an SASE with all
correspondence for which you’d like a
reply. Everyone so doing does get one. And
do enjoy continued happy E-landings
throughout the fall and winter—noting that
there is no associated residue of cold,
semisolid glop to clean! MA
Edition: Model Aviation - 2004/11
Page Numbers: 102,104,106
THIS COLUMN INCLUDES one meet announcement, new Ecatalog
info, comments on E-suppliers, an anniversary story,
speculation about Lithium batteries, some reader input, and a new
product.
John Jenks of the South Jersey Silent Flyers sent information
regarding a series of club-sponsored meets this season. Unfortunately,
the info came too late for me to share most of it and barely in time for
the RC Electrics meet on October 10. (Ya gotta get the stuff to me
early!)
The meet will have plaques for several events, including pylon,
limbo, and AULD (All-Up/Last-Down). You can get more details from
John at (856) 983-7024 or from Bob Bunting at (856) 786-0798. You
can get directions to the Marlton, New Jersey, field at www.sjsf.org.
I buy most of my supplies at a local hobby shop because it’s close and
because I believe in supporting my local business community. This
often costs me a bit more, but I feel that it’s worth it. However, I also
purchase some mail-order E-stuff.
One of my favorite mail-order suppliers is New Creations R/C
Bob Kopski, 25 West End Dr., Lansdale PA 19446
RADIO CONTROL ELECTRICS
AXI Outrunner motor mounted in REVOLT! and ready to test-fly.
Ample room is left over in motor-compartment area.
West Mountain Radio CBA interfaced with Bob’s personal
computer via USB cable. A seven-cell KAN 950 pack is under test.
(Box 496, Willis TX 77378; Tel.: [936] 856-4630; Web site:
www.newcreations-rc.com). I’ve been buying from this company for
years. These knowledgeable people are a pleasure to talk to, and their
service is super! Kirk Massey—head aeromodeler at New Creations
R/C—tells me he’s updating the catalog, and it should be available by
the time you read this. I want one of those!
I’ve had great experiences with other suppliers, large and small. A
good experience is the norm. But I’ve learned that there are the other
kind as well. Paradoxically, I had a bad encounter with a high-profile
operation. This supplier presents a glowing image with its full-page
color print advertising and its inviting Web site. But for me, that’s
about all this vendor has to offer.
The online ordering process was misleading. “Out of stock” items
were not identified (most companies do identify them), but my credit
card was quickly charged anyway (most companies don’t do that). I’ve
since paid my credit card bill, but I still don’t have the stuff I paid for
(weeks waiting), and I’ve not been able to get a believable delivery
date. Another goodie was that the customer service E-mail address
didn’t work.
There’s more bad stuff, but I’ll end this by suggesting that you
place your first order with any new-to-you supplier by telephone. It’s
easier to know what you’re dealing with, and you can better determine
if you want to give your card number out. Caveat emptor.
This issue marks the 10th anniversary of my Revolt! construction
article being published in MA. The now-obscure design has since
accrued a long and unusual flight log.
Revolt! was conceived as a test vehicle for E-stuff. It is otherwise a
ho hum-looking cabin-type design, suggesting “boring” to many. Since
it was intended to “carry stuff,” it has large cabin and motor
compartments, 600 square inches of high-lift wing section, and is a
basically stable design overall. Once trimmed, it is perfectly capable of
stable “free flight” performance.
This aircraft has served its intended purpose well throughout the
decade, and it still does, although to a much lesser degree than in years
past. Still, of the many models in my hangar, it’s the most flown.
As a power-system test vehicle, Revolt! has been flown with feeble
600-size direct-drive can motors on seven cells up to geared
AstroFlight 40 Cobalts on 21 cells. (Yes, that is all in one airplane!)
Other power systems included a wide variety of motors, such as
early Keller and Robbe products, “car motor”-
based products, nearly all classic AstroFlight
products, and contemporary brushless stuff. A
photo shows a decade-old Revolt! set up to try
an AXI Outrunner motor, which is new as I
write this.
Unlike all previous installations, the AXI
Outrunner presented a mounting challenge.
The other motors—geared or not—were
mounted on the accommodating “VEE” block
mount system designed into Revolt! However,
the AXI cannot be mounted in a VEE block;
the motor housing rotates!
I decided to attach a removable 1⁄8 birchplywood
nose plate to Revolt!, and then fix the
AXI front-end bell behind that. If this suggests
bad planning to you, please remember that
Outrunners did not exist when Revolt! was
designed!
In addition to serving as a power-system
test bed, Revolt! has been pressed into service
flight-testing ESCs and radio equipment, has
had “glitch-counting” and telemetry
equipment installed, and several readers have
installed cameras.
But beyond all that, Revolt! has shown its
abilities as an unplanned basic trainer for some
readers. Through the years I have routinely
handed the sticks of this docile craft to youthful
and senior bystanders and talked them through
Shown is the CBA display screen. Here it is reporting 0.72 ampere-hours capacity for
old KAN 950 seven-cell pack under 5-amp test current drain.
the air—knowing that the airplane was forgiving.
Thus this simplistic three-channel E-aero design has become less of
a test resource and much more of a regular companion through the
years. I typically take two or three E-airplanes to the field each time I
go, and a Revolt! is usually one of them. It’s my relaxing “comfort”
airplane—it just feels good—with its
normally installed 15G/12-cell system.
Out of curiosity and for purposes here, I
just reviewed my Revolt! flight logs to date
(July 2, 2004), beginning with the first on
April 10, 1993. The tally: 2,110 flights! How
many flights do you have on your favorite
model?
I’m sure that by now, nearly all Eaeromodelers
are using, or are at least aware
of, today’s popular battery technology:
Lithium-Polymer, more commonly known as
“Li-Poly.” Li-Poly has hit the market in more
of a “flash flood” fashion than past battery
products have. It seems as though each month
more companies and product labels are added
to the already large supplier list. And the
warnings and cautions about the use and
abuse of Li-Poly continue.
With the product itself, most Eaeromodelers
are probably also familiar with
the safety “dos” and “don’ts,” so I’m not
going to belabor the detail here. Rather, with
the continuing strong handling cautions mixed
with emerging tales of woe, I cannot help but
wonder if this product was not introduced
prematurely.
Noting that there are no similar cautions
and costly losses associated with other
Lithium-powered consumer applications, such
as cell phones, pagers, laptops, etc., why is
our E-aeromodeling application so different?
I think the answer lies with the consumer
products having built-in protection devices,
dedicated (inflexible) chargers, and unique
application interfaces that protect the user—
from himself or herself. You can’t easily use
the consumer stuff “wrong.”
Our stuff, having essentially no
“containment” as in the preceding, does not
have protections built in or dedicated
interfaces. In effect, safe handling lies totally
in our hands, so it is not always in a firm grip.
I have a feeling that this will eventually
change—out of necessity.
I might imagine a standardized Li-Poly
“hobby-use interface,” bounding charging and
application variables. A possible form of
this—perhaps instead of or in addition to
electronics built into each pack—would be
standardized connectors. I could imagine
multipin interfaces with connections to each
cell of a pack assembly and a “standard
specification” charger interface emerging. I’m
sure there must be other options as well. I’m
just guessing.
Whatever the case, it’s hard to imagine the
risks and losses associated with present-day
Li-Poly continuing without eventual impact
on all aeromodelers, such as increasing
insurance premiums. All reader comment on
this topic is welcome.
While on the subject of Li-Poly, the
opening sentence of the Universal Slow
Charger article published in the September
2000 MA reads: “The Universal Slow Charger
is a uniquely capable, versatile, flexible
charger design that can accommodate all
aeromodeling rechargeables I know of, and
more.”
This was true at the time, but it is no
longer true. Do not use the Universal Slow
Charger with Li-Poly batteries!
Several readers reacted to the August
column’s discussion about switches used in
Electrics. Surprisingly, one recurring input I
received was concerning the use of small
arming toggle switches with brushless
systems. In that column I described how
such switches can be instantly destroyed by
the presence of large electrolytic capacitors
on the power-input connections of most
brushless ESCs.
Several readers independently suggested
the same solution to this problem. Although
the specifics varied a bit among them, the
basic idea was to install a second switch in
parallel with the first—except the second
would have in series with it a small-value
resistor.
The idea is to close this second path first,
allowing the ESC input capacitors to safely
charge up to battery voltage via the resistor
(takes less than a second), and then close the
“real” arming switch. This way, the latter is
protected from the huge surge of current
upon initial closure because it’s closing on
an already charged capacitor.
I agree that this is a sound approach to
the problem, but I’d prefer not to have to
mount a second switch. Nor do I like having
to remember to sequence the two-switch
power-up operation. So I’m still looking for
a simpler approach—perhaps an impossible
quest. Meanwhile, thanks to those who
picked up on the topic and reacted with
workable inputs for us all. (I’m now looking
at a Revolt! to test this in!)
West Mountain Radio (18 Sheehan Ave.,
Norwalk CT 06854; Tel.: [203] 853-8080;
Web site: www.westmountainradio.com) is
a popular supplier of amateur-radio-related
equipment. However, the guys at the
company are also active aeromodelers.
Since both hobbies use rechargeable
batteries, it’s no surprise to see the
company introduce a related new product:
the Computerized Battery Analyzer, or
CBA.
This easy-to-use device interfaces with a
personal computer via a USB port and is
powered from that port as well. With it, you
can easily keep tabs on the health of all your
rechargeables during their lifetime.
The associated software allows the user
to enter varied test parameters including cell
count (1-48 volts), battery type, discharge
current, cutoff voltage, etc. Once discharge
is initiated, the program presents a discharge
screen, as shown for a seven-cell 950 KAN
NiMH pack. The vertical scale is for battery
voltage and the horizontal axis displays
ampere-hours. The latter display “grows” as
test time accumulates.
I have not tried all of the features yet, but
the software allows battery-test naming and
permits “overlays” of more than one battery
rundown for comparison purposes. Other
features include temperature monitoring.
The CBA covers all of our common
rechargeable battery types—including Li-
Poly. This device is not a “cycler,” meaning
that it has no charging function.
I will have more in the future, but in the
meantime you can check out the CBA on
the West Mountain Radio Web site. Then
put it on your “seasonal” wish list!
West Mountain Radio also offers
Anderson Power Poles at great prices—such
as 25 pair for $19.95. Other quantities are
available.
Thus ends another installment. My next RC
Electrics column will be in the January
2005 issue; December is the dedicated Nats
issue.
Please enclose an SASE with all
correspondence for which you’d like a
reply. Everyone so doing does get one. And
do enjoy continued happy E-landings
throughout the fall and winter—noting that
there is no associated residue of cold,
semisolid glop to clean! MA