been on the shelf for a long time. That just
made me all the more determined. It took
days and a great deal of blind probing (since
I didn’t have receiver drawings), but finally
I found a ratty timing waveform in the
decoder circuitry.
Specifically, there is a simple R-C
(resistance-capacitance) network used in
conjunction with the decoder IC (integrated
circuit) to detect the signal frame and reset
the decoder count for each frame received.
The classic exponential waveform on this
capacitor was jittery and of variable
amplitude so that the decoder did not
always reset. Simply put: it caused a
crash—or maybe two.
THIS COLUMN offers a communication
reminder, follows up on some recent
column topics, and shares reader input and
questions.
As thousands of readers have learned
throughout the years, I really do respond to
reader mail accompanied with an SASE. I
conclude every column with my invitation
for you to write, and in those cases in which
you want a reply, an SASE will get it for
you. Of course, sometimes I get a “oneway”
note that does not need a reply, and
that’s fine too.
The best way to communicate with me is
at the address in the column header. Please
don’t write to me via MA; that just delays a
response and adds to the burden of the MA
staff members who have to forward your
mail to me.
Also, I do not use E-mail for
correspondence. Trying this route via MA
also burdens the staff—and me. Just send
me a letter directly and include an SASE
when a reply is desired. This has been
working well for everyone involved for
approximately 20 years.
The April column had hardly hit the streets
when reader reaction to the brief discussion
of problematic ACE Pro 810/RCD Platinum
(AM) receivers came pouring in.
Sometimes readers thoroughly amaze me!
That was a nonelectric topic that I
reluctantly included, and I wasn’t sure if
anyone would have an interest. I’m no
longer unsure; I received fast and heavy
reader reaction! So to accommodate that
broad-based interest, following is a review
with greater detail.
The April column briefly described an
intermittent problem I experienced with an
old ACE Pro 810 receiver that resulted in a
crash. “Intermittents” are usually the result
of loose component solder connections,
loose connectors, or faulty switches. The
classic approach to tracking them down
might include wiggling and tapping the
suspect items and/or heating/cooling the
suspect areas in the hopes of finding what’s
wrong.
This approach did not work with what
certainly seemed to be an otherwise classic
intermittent receiver—in the air and on the
bench. Not being one to give up, I
continued to pursue the erratic operation,
and this pursuit was given impetus when I
found that I had another receiver displaying
the same behavior on the bench.
This second receiver—associated with
an unexplained crash some years past—had
Bob Kopski, 25 West End Dr., Lansdale PA 19446
RADIO CONTROL ELECTRICS
Eric Einarsson’s (Los Gatos CA) “Double Dual Universal Slow Charger” is beautifully
built inside and out. This is massive slow-charging capability!
AstroFlight Firefly coreless motor retrofitted in GWS fan via matching mating adapter
ring. Astro’s proprietary speed control is not much larger than Futaba-type connector.
July 2004 109
07sig4.QXD 4/23/04 12:40 pm Page 109
110 MODEL AVIATION
Gary Wright’s E3D-XL dazzles the crowd at the 2003 NEAT Fair.
The model is powered by a Hacker/Li-Poly system.
The Northeast Sailplane Products hangar at the 2003 NEAT Fair.
These ARFs are attractive, and many flew that weekend.
Still thinking there was something loose
in this immediate circuit area, I continued a
focused wiggle and tap and heating and
cooling, but no luck. It seemed as though
nothing was loose. In frustration, I removed
the involved capacitor from the board, and
behold! It was installed backward! Then I
looked at my other two Pro 810s and the
similar RCD Platinum, and, sure enough,
the same capacitor was installed incorrectly
in all!
The capacitor is a 0.1 uF tantalum
electrolytic—a polarized capacitor. Such
parts must be installed with the correct
polarity (as discussed in the June column).
Because the actual signal levels on this
component in these receivers are quite
small, the capacitors actually survived the
misuse for a long time.
Eventually, it appears, the backward bias
caused a failure taking the form of varying
capacitance value and/or a variable leakage
value. Whatever it was, the fix was to
remove the part, discard it, and install a
replacement—correctly oriented
(polarized).
Because I did not expect the high level
of reader interest, I did not go into all this
detail or into the corrective methodology in
that April column. Now I wish I had! I did
send the many readers who inquired a color
printout of the receiver, highlighting the
troubled capacitor, and detailed instructions
regarding the replacement part.
I will supply this info to those so
inquiring (who include an SASE). I did toy
with including the details here, but the
larger color picture I can supply is better
than might be reproduced in column format.
The repair does require some
desoldering/soldering skills and proper
tools; it is a tightly packed board. If you
feel uncomfortable with the undertaking,
find a skilled friend who can help you or
send it to an established RC repair service
along with the descriptive sheet I can
provide.
I do not know for sure that every Pro
810 and/or RCD Platinum receiver out there
was manufactured incorrectly—only that
my four receivers representing the two
different manufacturers and purchased over
time were.
Given that this issue has been addressed
in an otherwise electric-dedicated column,
and that surely not all MA readers read this
column, I suspect that many receivers out
there may be problematic for our wet-power
and other flying friends. You might want to
pass this discussion along to those you
know who might benefit.
Since some have asked, I have never
seen this problem with the predecessor ACE
Silver Seven receiver, and I do not know if
there is a similar consideration with the
ACE Pro Star (FM) receivers.
One of the most popular feature articles
I’ve had published is the “Universal Slow
Charger” (USC) in the September 2000 MA.
I offered the USC as a “single” or “dual”
version. Since then, many have built the
USC in one form or another, and I’ve
included an occasional reader photo. This
month’s USC photo by reader Eric
Einarsson of Los Gatos CA is particularly
noteworthy.
Eric expanded on the USC idea and
personalized it into his “Double Dual
Universal Slow Charger.” Basically, he
built two duals into one impressive single
enclosure. That means he has four
independently adjustable 0-500 mA, 1- to
42-cell outputs, each with selectable
metering—all in one place. The photo
showing the magnificent-looking job inside
the box was unusable here.
And as many other readers have, Eric
chose his preferred output connector to that
originally published. It really makes me feel
good to witness so much reader interest in
such projects! My thanks to Eric for sharing
this with us.
A reader recently inquired how far away is
far enough to route an antenna wire from
“stuff” in the airplane. The realistic answer
is that it varies.
The April and May columns included
considerable discussion about noise issues
and included a simple test scheme to aid in
dealing with these matters. With that
information as background, I can suggest
that receiver antenna “dress” considerations
can be studied using the same methodology.
For a given installation of receiver,
servos, associated battery if any, ESC,
motor, and motor battery, one can dress the
antenna lead near and far from this stuff and
run the bench tests described in reference
columns.
I have experienced a broad range of
related effects in so doing. I have seen it
possible to drape the antenna wire around
and about the “stuff,” and have no
associated noise problems on the bench. On
the other hand, I’ve seen where the antenna
wire had to be routed well away from
everything in the installation. So it varies.
It’s clear why there can be such a broad
range of outcome. As seen in the reference
discussions, just changing a receiver brand
can make a huge difference. And larger
power systems are generally more capable
noise sources.
Also, note that the typical power system
is intimately connected to the receiver
system via the ESC cable. Thus if
something in a power system is a
“noisemaker,” that contribution might
readily be found resident on servos too; it is
conducted there. The only ways this would
be less the case would be with the use of
chokes in the ESC lead or with an
optocoupled ESC.
All these are my reasons for saying “It
varies” in response to that reader’s antenna
dress question. If you have this concern,
bench test using the technique described in
the reference columns. It’s easy and helpful,
although I must admit that when I first
wrote it up, I was not thinking about the
antenna dress question.
Another reader input was one of those
one-way letters that did not need a reply.
Basically, a reader named Bill wanted to tell
me about some trouble he was having
charging packs that had not been charged
for some time.
07sig4.QXD 4/23/04 12:40 pm Page 110
He was routinely experiencing a fault
indication of “no battery” on his peak
charger display upon plugging in the pack.
He found that he had to force some charge
into the pack from another (“dumb”)
charger, and thereafter his usual charger
worked normally.
Then he read the April column. Aha! Bill
suddenly realized that he had one of those
ESCs with an on/off switch that was not
truly a “power switch.” So at the end of a
flying session, the connected pack was still
being drained slowly by the ESC electronics
so that it was truly flat dead the next time he
went to fly. His charger could not recognize
zero volts and indicated “no battery.”
Aside from the charging annoyance that
Bill experienced, it’s not good at all to drain
a pack (any pack) all the way. It’s an instant
killer for Li-Poly batteries and damaging to
Ni-Cd and NiMH, although they take longer
to “kill.” Bill wanted me to tell everyone all
about this—again.
The NEAT (Northeast Electric Aircraft
Technology) Fair feature in the March MA
brought in several letters, including some
agreeing with my comment about motor
specifications/labels. On page 64 of that
article, I wrote:
“ … there exists an often-confusing
abundance of brushless motors ... The result
is that you can fly whatever you’re likely to
want to fly brushless, but you do have to
figure out which manufacturer/product you
want. As many lamented to me, this is not
necessarily easy to do.
“In that respect, the industry has
simultaneously done a magnificent job
producing and a terrible job describing this
product. As with any technically intensive
consumer-product category with multiple
sources, it is important for suppliers to
collectively help the user use it easily. A
standardized, concise, meaningful motor
label would go a long way.”
So why can’t the motor suppliers get
together and agree on some standardized
label—a way to help aeromodelers
understand and compare and choose among
the zillion motors on the market?
What exists now—nomenclature
gibberish—is worse than nothing; it’s
counterproductive. If it’s possible to put two
rovers on Mars, why is it impossible for a
typical aeromodeler, who has some minimal
understanding, to pick up a motor, glance at
the label/part description, and immediately
be able to ballpark to what application that
particular motor is best suited?
This concludes another column. Please
include an SASE with any
correspondence—to my address—for which
you’d like a reply. Everyone so doing does
get one. If there is anyone out there who did
this and did not hear back, I never received
your letter!
Happy summertime (or anytime) Elandings,
everyone! MA
112 MODEL AVIATION
Very light (26 oz.) Nomex honey-comb fuselage, pre-built (11 oz ea.)
wing panels using foam rib technique, all balsa pre-built stab and rudder.
This design uses the our proven Typhoon 2+2 wing and follows the
Typhoon’s and moments and areas as closely as possible.
417-725-7755
www.gatorrc.com
VISA & MasterCard Welcomed!
Giles 202gt package......................................$795.00
Includes: fuselage, clear canopy, carbon fiber landing gear,
fiberglass wheel pants, G202 Dave Brown Wheels, complete
full-size plans, 1”x30” wing tube and socket set, wing adjuster
kit, plug-in adjustable stab kit, dzus latch kit.
Pre-Built built-up wing panels.....................$395.00
Pre-Built stab, elevators, rudder .................$175.00
Foam Cores; wing, stab and rudder..............$94.00
Wing Span: 2 meters (78.5”)
Length: 2 meters (78.5”)
Wing Area: 1170 sq. in.
Weight: 10.25-10.5 lbs.
Engine: 1.40 2 or 4-stroke
29.7%
SCALE
Take a bite out of the sky with
the Giles 202gt from Gator R/C!
2100 N Old Mill Rd
Brookline, MO 65619
Min. $6.50
Shipping&Handling per order
ESTATE LIQUIDATION SERVICES
For information, call 281-998-2529, or send SASE to:
GCBM R/C Models Inc.
PO Box 7967, Pasadena, TX 77508 • website: gcbmrc.com
• We buy: R/C Airplane Kits, ARF’s,
Engines, Radios, Field Equipment,
Building Accessories
• Entire Estates
• Vintage and Antique Collections
• Hobby Shop Inventories
• New or Used
• Pick-up Service Available
07sig4.QXD 4/23/04 12:40 pm Page 112
Edition: Model Aviation - 2004/07
Page Numbers: 109,110,112
Edition: Model Aviation - 2004/07
Page Numbers: 109,110,112
been on the shelf for a long time. That just
made me all the more determined. It took
days and a great deal of blind probing (since
I didn’t have receiver drawings), but finally
I found a ratty timing waveform in the
decoder circuitry.
Specifically, there is a simple R-C
(resistance-capacitance) network used in
conjunction with the decoder IC (integrated
circuit) to detect the signal frame and reset
the decoder count for each frame received.
The classic exponential waveform on this
capacitor was jittery and of variable
amplitude so that the decoder did not
always reset. Simply put: it caused a
crash—or maybe two.
THIS COLUMN offers a communication
reminder, follows up on some recent
column topics, and shares reader input and
questions.
As thousands of readers have learned
throughout the years, I really do respond to
reader mail accompanied with an SASE. I
conclude every column with my invitation
for you to write, and in those cases in which
you want a reply, an SASE will get it for
you. Of course, sometimes I get a “oneway”
note that does not need a reply, and
that’s fine too.
The best way to communicate with me is
at the address in the column header. Please
don’t write to me via MA; that just delays a
response and adds to the burden of the MA
staff members who have to forward your
mail to me.
Also, I do not use E-mail for
correspondence. Trying this route via MA
also burdens the staff—and me. Just send
me a letter directly and include an SASE
when a reply is desired. This has been
working well for everyone involved for
approximately 20 years.
The April column had hardly hit the streets
when reader reaction to the brief discussion
of problematic ACE Pro 810/RCD Platinum
(AM) receivers came pouring in.
Sometimes readers thoroughly amaze me!
That was a nonelectric topic that I
reluctantly included, and I wasn’t sure if
anyone would have an interest. I’m no
longer unsure; I received fast and heavy
reader reaction! So to accommodate that
broad-based interest, following is a review
with greater detail.
The April column briefly described an
intermittent problem I experienced with an
old ACE Pro 810 receiver that resulted in a
crash. “Intermittents” are usually the result
of loose component solder connections,
loose connectors, or faulty switches. The
classic approach to tracking them down
might include wiggling and tapping the
suspect items and/or heating/cooling the
suspect areas in the hopes of finding what’s
wrong.
This approach did not work with what
certainly seemed to be an otherwise classic
intermittent receiver—in the air and on the
bench. Not being one to give up, I
continued to pursue the erratic operation,
and this pursuit was given impetus when I
found that I had another receiver displaying
the same behavior on the bench.
This second receiver—associated with
an unexplained crash some years past—had
Bob Kopski, 25 West End Dr., Lansdale PA 19446
RADIO CONTROL ELECTRICS
Eric Einarsson’s (Los Gatos CA) “Double Dual Universal Slow Charger” is beautifully
built inside and out. This is massive slow-charging capability!
AstroFlight Firefly coreless motor retrofitted in GWS fan via matching mating adapter
ring. Astro’s proprietary speed control is not much larger than Futaba-type connector.
July 2004 109
07sig4.QXD 4/23/04 12:40 pm Page 109
110 MODEL AVIATION
Gary Wright’s E3D-XL dazzles the crowd at the 2003 NEAT Fair.
The model is powered by a Hacker/Li-Poly system.
The Northeast Sailplane Products hangar at the 2003 NEAT Fair.
These ARFs are attractive, and many flew that weekend.
Still thinking there was something loose
in this immediate circuit area, I continued a
focused wiggle and tap and heating and
cooling, but no luck. It seemed as though
nothing was loose. In frustration, I removed
the involved capacitor from the board, and
behold! It was installed backward! Then I
looked at my other two Pro 810s and the
similar RCD Platinum, and, sure enough,
the same capacitor was installed incorrectly
in all!
The capacitor is a 0.1 uF tantalum
electrolytic—a polarized capacitor. Such
parts must be installed with the correct
polarity (as discussed in the June column).
Because the actual signal levels on this
component in these receivers are quite
small, the capacitors actually survived the
misuse for a long time.
Eventually, it appears, the backward bias
caused a failure taking the form of varying
capacitance value and/or a variable leakage
value. Whatever it was, the fix was to
remove the part, discard it, and install a
replacement—correctly oriented
(polarized).
Because I did not expect the high level
of reader interest, I did not go into all this
detail or into the corrective methodology in
that April column. Now I wish I had! I did
send the many readers who inquired a color
printout of the receiver, highlighting the
troubled capacitor, and detailed instructions
regarding the replacement part.
I will supply this info to those so
inquiring (who include an SASE). I did toy
with including the details here, but the
larger color picture I can supply is better
than might be reproduced in column format.
The repair does require some
desoldering/soldering skills and proper
tools; it is a tightly packed board. If you
feel uncomfortable with the undertaking,
find a skilled friend who can help you or
send it to an established RC repair service
along with the descriptive sheet I can
provide.
I do not know for sure that every Pro
810 and/or RCD Platinum receiver out there
was manufactured incorrectly—only that
my four receivers representing the two
different manufacturers and purchased over
time were.
Given that this issue has been addressed
in an otherwise electric-dedicated column,
and that surely not all MA readers read this
column, I suspect that many receivers out
there may be problematic for our wet-power
and other flying friends. You might want to
pass this discussion along to those you
know who might benefit.
Since some have asked, I have never
seen this problem with the predecessor ACE
Silver Seven receiver, and I do not know if
there is a similar consideration with the
ACE Pro Star (FM) receivers.
One of the most popular feature articles
I’ve had published is the “Universal Slow
Charger” (USC) in the September 2000 MA.
I offered the USC as a “single” or “dual”
version. Since then, many have built the
USC in one form or another, and I’ve
included an occasional reader photo. This
month’s USC photo by reader Eric
Einarsson of Los Gatos CA is particularly
noteworthy.
Eric expanded on the USC idea and
personalized it into his “Double Dual
Universal Slow Charger.” Basically, he
built two duals into one impressive single
enclosure. That means he has four
independently adjustable 0-500 mA, 1- to
42-cell outputs, each with selectable
metering—all in one place. The photo
showing the magnificent-looking job inside
the box was unusable here.
And as many other readers have, Eric
chose his preferred output connector to that
originally published. It really makes me feel
good to witness so much reader interest in
such projects! My thanks to Eric for sharing
this with us.
A reader recently inquired how far away is
far enough to route an antenna wire from
“stuff” in the airplane. The realistic answer
is that it varies.
The April and May columns included
considerable discussion about noise issues
and included a simple test scheme to aid in
dealing with these matters. With that
information as background, I can suggest
that receiver antenna “dress” considerations
can be studied using the same methodology.
For a given installation of receiver,
servos, associated battery if any, ESC,
motor, and motor battery, one can dress the
antenna lead near and far from this stuff and
run the bench tests described in reference
columns.
I have experienced a broad range of
related effects in so doing. I have seen it
possible to drape the antenna wire around
and about the “stuff,” and have no
associated noise problems on the bench. On
the other hand, I’ve seen where the antenna
wire had to be routed well away from
everything in the installation. So it varies.
It’s clear why there can be such a broad
range of outcome. As seen in the reference
discussions, just changing a receiver brand
can make a huge difference. And larger
power systems are generally more capable
noise sources.
Also, note that the typical power system
is intimately connected to the receiver
system via the ESC cable. Thus if
something in a power system is a
“noisemaker,” that contribution might
readily be found resident on servos too; it is
conducted there. The only ways this would
be less the case would be with the use of
chokes in the ESC lead or with an
optocoupled ESC.
All these are my reasons for saying “It
varies” in response to that reader’s antenna
dress question. If you have this concern,
bench test using the technique described in
the reference columns. It’s easy and helpful,
although I must admit that when I first
wrote it up, I was not thinking about the
antenna dress question.
Another reader input was one of those
one-way letters that did not need a reply.
Basically, a reader named Bill wanted to tell
me about some trouble he was having
charging packs that had not been charged
for some time.
07sig4.QXD 4/23/04 12:40 pm Page 110
He was routinely experiencing a fault
indication of “no battery” on his peak
charger display upon plugging in the pack.
He found that he had to force some charge
into the pack from another (“dumb”)
charger, and thereafter his usual charger
worked normally.
Then he read the April column. Aha! Bill
suddenly realized that he had one of those
ESCs with an on/off switch that was not
truly a “power switch.” So at the end of a
flying session, the connected pack was still
being drained slowly by the ESC electronics
so that it was truly flat dead the next time he
went to fly. His charger could not recognize
zero volts and indicated “no battery.”
Aside from the charging annoyance that
Bill experienced, it’s not good at all to drain
a pack (any pack) all the way. It’s an instant
killer for Li-Poly batteries and damaging to
Ni-Cd and NiMH, although they take longer
to “kill.” Bill wanted me to tell everyone all
about this—again.
The NEAT (Northeast Electric Aircraft
Technology) Fair feature in the March MA
brought in several letters, including some
agreeing with my comment about motor
specifications/labels. On page 64 of that
article, I wrote:
“ … there exists an often-confusing
abundance of brushless motors ... The result
is that you can fly whatever you’re likely to
want to fly brushless, but you do have to
figure out which manufacturer/product you
want. As many lamented to me, this is not
necessarily easy to do.
“In that respect, the industry has
simultaneously done a magnificent job
producing and a terrible job describing this
product. As with any technically intensive
consumer-product category with multiple
sources, it is important for suppliers to
collectively help the user use it easily. A
standardized, concise, meaningful motor
label would go a long way.”
So why can’t the motor suppliers get
together and agree on some standardized
label—a way to help aeromodelers
understand and compare and choose among
the zillion motors on the market?
What exists now—nomenclature
gibberish—is worse than nothing; it’s
counterproductive. If it’s possible to put two
rovers on Mars, why is it impossible for a
typical aeromodeler, who has some minimal
understanding, to pick up a motor, glance at
the label/part description, and immediately
be able to ballpark to what application that
particular motor is best suited?
This concludes another column. Please
include an SASE with any
correspondence—to my address—for which
you’d like a reply. Everyone so doing does
get one. If there is anyone out there who did
this and did not hear back, I never received
your letter!
Happy summertime (or anytime) Elandings,
everyone! MA
112 MODEL AVIATION
Very light (26 oz.) Nomex honey-comb fuselage, pre-built (11 oz ea.)
wing panels using foam rib technique, all balsa pre-built stab and rudder.
This design uses the our proven Typhoon 2+2 wing and follows the
Typhoon’s and moments and areas as closely as possible.
417-725-7755
www.gatorrc.com
VISA & MasterCard Welcomed!
Giles 202gt package......................................$795.00
Includes: fuselage, clear canopy, carbon fiber landing gear,
fiberglass wheel pants, G202 Dave Brown Wheels, complete
full-size plans, 1”x30” wing tube and socket set, wing adjuster
kit, plug-in adjustable stab kit, dzus latch kit.
Pre-Built built-up wing panels.....................$395.00
Pre-Built stab, elevators, rudder .................$175.00
Foam Cores; wing, stab and rudder..............$94.00
Wing Span: 2 meters (78.5”)
Length: 2 meters (78.5”)
Wing Area: 1170 sq. in.
Weight: 10.25-10.5 lbs.
Engine: 1.40 2 or 4-stroke
29.7%
SCALE
Take a bite out of the sky with
the Giles 202gt from Gator R/C!
2100 N Old Mill Rd
Brookline, MO 65619
Min. $6.50
Shipping&Handling per order
ESTATE LIQUIDATION SERVICES
For information, call 281-998-2529, or send SASE to:
GCBM R/C Models Inc.
PO Box 7967, Pasadena, TX 77508 • website: gcbmrc.com
• We buy: R/C Airplane Kits, ARF’s,
Engines, Radios, Field Equipment,
Building Accessories
• Entire Estates
• Vintage and Antique Collections
• Hobby Shop Inventories
• New or Used
• Pick-up Service Available
07sig4.QXD 4/23/04 12:40 pm Page 112
Edition: Model Aviation - 2004/07
Page Numbers: 109,110,112
been on the shelf for a long time. That just
made me all the more determined. It took
days and a great deal of blind probing (since
I didn’t have receiver drawings), but finally
I found a ratty timing waveform in the
decoder circuitry.
Specifically, there is a simple R-C
(resistance-capacitance) network used in
conjunction with the decoder IC (integrated
circuit) to detect the signal frame and reset
the decoder count for each frame received.
The classic exponential waveform on this
capacitor was jittery and of variable
amplitude so that the decoder did not
always reset. Simply put: it caused a
crash—or maybe two.
THIS COLUMN offers a communication
reminder, follows up on some recent
column topics, and shares reader input and
questions.
As thousands of readers have learned
throughout the years, I really do respond to
reader mail accompanied with an SASE. I
conclude every column with my invitation
for you to write, and in those cases in which
you want a reply, an SASE will get it for
you. Of course, sometimes I get a “oneway”
note that does not need a reply, and
that’s fine too.
The best way to communicate with me is
at the address in the column header. Please
don’t write to me via MA; that just delays a
response and adds to the burden of the MA
staff members who have to forward your
mail to me.
Also, I do not use E-mail for
correspondence. Trying this route via MA
also burdens the staff—and me. Just send
me a letter directly and include an SASE
when a reply is desired. This has been
working well for everyone involved for
approximately 20 years.
The April column had hardly hit the streets
when reader reaction to the brief discussion
of problematic ACE Pro 810/RCD Platinum
(AM) receivers came pouring in.
Sometimes readers thoroughly amaze me!
That was a nonelectric topic that I
reluctantly included, and I wasn’t sure if
anyone would have an interest. I’m no
longer unsure; I received fast and heavy
reader reaction! So to accommodate that
broad-based interest, following is a review
with greater detail.
The April column briefly described an
intermittent problem I experienced with an
old ACE Pro 810 receiver that resulted in a
crash. “Intermittents” are usually the result
of loose component solder connections,
loose connectors, or faulty switches. The
classic approach to tracking them down
might include wiggling and tapping the
suspect items and/or heating/cooling the
suspect areas in the hopes of finding what’s
wrong.
This approach did not work with what
certainly seemed to be an otherwise classic
intermittent receiver—in the air and on the
bench. Not being one to give up, I
continued to pursue the erratic operation,
and this pursuit was given impetus when I
found that I had another receiver displaying
the same behavior on the bench.
This second receiver—associated with
an unexplained crash some years past—had
Bob Kopski, 25 West End Dr., Lansdale PA 19446
RADIO CONTROL ELECTRICS
Eric Einarsson’s (Los Gatos CA) “Double Dual Universal Slow Charger” is beautifully
built inside and out. This is massive slow-charging capability!
AstroFlight Firefly coreless motor retrofitted in GWS fan via matching mating adapter
ring. Astro’s proprietary speed control is not much larger than Futaba-type connector.
July 2004 109
07sig4.QXD 4/23/04 12:40 pm Page 109
110 MODEL AVIATION
Gary Wright’s E3D-XL dazzles the crowd at the 2003 NEAT Fair.
The model is powered by a Hacker/Li-Poly system.
The Northeast Sailplane Products hangar at the 2003 NEAT Fair.
These ARFs are attractive, and many flew that weekend.
Still thinking there was something loose
in this immediate circuit area, I continued a
focused wiggle and tap and heating and
cooling, but no luck. It seemed as though
nothing was loose. In frustration, I removed
the involved capacitor from the board, and
behold! It was installed backward! Then I
looked at my other two Pro 810s and the
similar RCD Platinum, and, sure enough,
the same capacitor was installed incorrectly
in all!
The capacitor is a 0.1 uF tantalum
electrolytic—a polarized capacitor. Such
parts must be installed with the correct
polarity (as discussed in the June column).
Because the actual signal levels on this
component in these receivers are quite
small, the capacitors actually survived the
misuse for a long time.
Eventually, it appears, the backward bias
caused a failure taking the form of varying
capacitance value and/or a variable leakage
value. Whatever it was, the fix was to
remove the part, discard it, and install a
replacement—correctly oriented
(polarized).
Because I did not expect the high level
of reader interest, I did not go into all this
detail or into the corrective methodology in
that April column. Now I wish I had! I did
send the many readers who inquired a color
printout of the receiver, highlighting the
troubled capacitor, and detailed instructions
regarding the replacement part.
I will supply this info to those so
inquiring (who include an SASE). I did toy
with including the details here, but the
larger color picture I can supply is better
than might be reproduced in column format.
The repair does require some
desoldering/soldering skills and proper
tools; it is a tightly packed board. If you
feel uncomfortable with the undertaking,
find a skilled friend who can help you or
send it to an established RC repair service
along with the descriptive sheet I can
provide.
I do not know for sure that every Pro
810 and/or RCD Platinum receiver out there
was manufactured incorrectly—only that
my four receivers representing the two
different manufacturers and purchased over
time were.
Given that this issue has been addressed
in an otherwise electric-dedicated column,
and that surely not all MA readers read this
column, I suspect that many receivers out
there may be problematic for our wet-power
and other flying friends. You might want to
pass this discussion along to those you
know who might benefit.
Since some have asked, I have never
seen this problem with the predecessor ACE
Silver Seven receiver, and I do not know if
there is a similar consideration with the
ACE Pro Star (FM) receivers.
One of the most popular feature articles
I’ve had published is the “Universal Slow
Charger” (USC) in the September 2000 MA.
I offered the USC as a “single” or “dual”
version. Since then, many have built the
USC in one form or another, and I’ve
included an occasional reader photo. This
month’s USC photo by reader Eric
Einarsson of Los Gatos CA is particularly
noteworthy.
Eric expanded on the USC idea and
personalized it into his “Double Dual
Universal Slow Charger.” Basically, he
built two duals into one impressive single
enclosure. That means he has four
independently adjustable 0-500 mA, 1- to
42-cell outputs, each with selectable
metering—all in one place. The photo
showing the magnificent-looking job inside
the box was unusable here.
And as many other readers have, Eric
chose his preferred output connector to that
originally published. It really makes me feel
good to witness so much reader interest in
such projects! My thanks to Eric for sharing
this with us.
A reader recently inquired how far away is
far enough to route an antenna wire from
“stuff” in the airplane. The realistic answer
is that it varies.
The April and May columns included
considerable discussion about noise issues
and included a simple test scheme to aid in
dealing with these matters. With that
information as background, I can suggest
that receiver antenna “dress” considerations
can be studied using the same methodology.
For a given installation of receiver,
servos, associated battery if any, ESC,
motor, and motor battery, one can dress the
antenna lead near and far from this stuff and
run the bench tests described in reference
columns.
I have experienced a broad range of
related effects in so doing. I have seen it
possible to drape the antenna wire around
and about the “stuff,” and have no
associated noise problems on the bench. On
the other hand, I’ve seen where the antenna
wire had to be routed well away from
everything in the installation. So it varies.
It’s clear why there can be such a broad
range of outcome. As seen in the reference
discussions, just changing a receiver brand
can make a huge difference. And larger
power systems are generally more capable
noise sources.
Also, note that the typical power system
is intimately connected to the receiver
system via the ESC cable. Thus if
something in a power system is a
“noisemaker,” that contribution might
readily be found resident on servos too; it is
conducted there. The only ways this would
be less the case would be with the use of
chokes in the ESC lead or with an
optocoupled ESC.
All these are my reasons for saying “It
varies” in response to that reader’s antenna
dress question. If you have this concern,
bench test using the technique described in
the reference columns. It’s easy and helpful,
although I must admit that when I first
wrote it up, I was not thinking about the
antenna dress question.
Another reader input was one of those
one-way letters that did not need a reply.
Basically, a reader named Bill wanted to tell
me about some trouble he was having
charging packs that had not been charged
for some time.
07sig4.QXD 4/23/04 12:40 pm Page 110
He was routinely experiencing a fault
indication of “no battery” on his peak
charger display upon plugging in the pack.
He found that he had to force some charge
into the pack from another (“dumb”)
charger, and thereafter his usual charger
worked normally.
Then he read the April column. Aha! Bill
suddenly realized that he had one of those
ESCs with an on/off switch that was not
truly a “power switch.” So at the end of a
flying session, the connected pack was still
being drained slowly by the ESC electronics
so that it was truly flat dead the next time he
went to fly. His charger could not recognize
zero volts and indicated “no battery.”
Aside from the charging annoyance that
Bill experienced, it’s not good at all to drain
a pack (any pack) all the way. It’s an instant
killer for Li-Poly batteries and damaging to
Ni-Cd and NiMH, although they take longer
to “kill.” Bill wanted me to tell everyone all
about this—again.
The NEAT (Northeast Electric Aircraft
Technology) Fair feature in the March MA
brought in several letters, including some
agreeing with my comment about motor
specifications/labels. On page 64 of that
article, I wrote:
“ … there exists an often-confusing
abundance of brushless motors ... The result
is that you can fly whatever you’re likely to
want to fly brushless, but you do have to
figure out which manufacturer/product you
want. As many lamented to me, this is not
necessarily easy to do.
“In that respect, the industry has
simultaneously done a magnificent job
producing and a terrible job describing this
product. As with any technically intensive
consumer-product category with multiple
sources, it is important for suppliers to
collectively help the user use it easily. A
standardized, concise, meaningful motor
label would go a long way.”
So why can’t the motor suppliers get
together and agree on some standardized
label—a way to help aeromodelers
understand and compare and choose among
the zillion motors on the market?
What exists now—nomenclature
gibberish—is worse than nothing; it’s
counterproductive. If it’s possible to put two
rovers on Mars, why is it impossible for a
typical aeromodeler, who has some minimal
understanding, to pick up a motor, glance at
the label/part description, and immediately
be able to ballpark to what application that
particular motor is best suited?
This concludes another column. Please
include an SASE with any
correspondence—to my address—for which
you’d like a reply. Everyone so doing does
get one. If there is anyone out there who did
this and did not hear back, I never received
your letter!
Happy summertime (or anytime) Elandings,
everyone! MA
112 MODEL AVIATION
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