Q336: “I’ve seen references in your column to electric powered
control line flying and the successes Bob Hunt has had with such
planes. But I heard recently that there is now a move towards indoor
electric powered control line flying.
“What can you tell me about this and whom might I contact for
more details?”
A336: One of the people who has been actively developing this
concept is Bob Wilder of Colleyville, Texas. He has been known for
years for his many indoor RC endurance records, but Bob has always
been fond of CL flying, and last year he put his talents to work on
some new concepts for indoor CL flying.
What Bob has come up with involves flying electric-powered CL
models from 27- and 32-foot lines in school gymnasiums and similar
indoor facilities. The beauty of doing this is that the airplanes are
constrained by the
lines they are
attached to; therefore,
they cannot go astray
and hit walls,
ceilings, or even
basketball hoops.
School gyms are
certainly more
available to modelers
than those massive
inflatable sports
domes.
The type of
Electric indoor CL flying
March 2008 89
? Frequently Asked Questions Bob Aberle | [email protected]
Also included in this column:
• Six-meter RC receivers
• Amateur radio licenses and
renewals
• Micro scale plans
Bob Wilder (L) flies electric CL combat with Rod Taylor in a
Texas school gym. These models won’t hit walls or the ceiling.
Underside of the two-line aircraft. The yellow item in heatshrink
wrap is the special timer discussed in the text.
Bob Wilder flies these two Shoestrings, at the top, and this
Buster in electric-powered indoor CL. All weigh 6-8 ounces.
03sig3.QXD 1/25/08 9:51 AM Page 89aircraft Bob is developing tends to weigh 6-8 ounces, powered by
brushless motors with input power of 30-50 watts. The models are
mostly made from Depron foam sheet material that, in many cases, is
reinforced with carbon-fiber tape.
I had been following the progress of Bob’s design efforts for the
past year. But I didn’t understand everything he was doing until I
witnessed his demonstration flying at the big JR Indoor Electric
Festival held in Columbus, Ohio, this past November. He is setting a
goal to develop indoor CL designs to fly in such categories as scale,
racing, combat, carrier, speed, stunt, and general sport.
Bob has come up with two interesting concepts, the first of which
employs conventional two-line control with the standard bellcrank that
operates the elevator (and sometimes coordinated flaps) on the aircraft.
In this configuration the brushless motor is controlled by an ESC that
is, in turn, attached to a special Multiple Function Electronic Timer
device that Bob is offering.
The timer can be programmed to time your flight and cut off power
before the battery begins to wear down. It also allows the user to adjust
the motor speed. This timer weighs only 3.2 grams and is certainly not
expensive.
Now comes the real fun! Some people have difficulty flying CL
because we get nauseated when turning rapidly in circles. Watching
gymnasium walls flash by might even exaggerate this condition. To
cope with that problem Bob came up with a single-control-line aircraft
that is tethered to a centrally located pylon.
The timer I referenced is unplugged, and in its place goes an RC
receiver (much like replacing a module) along with an RC servo. The
pilot stands outside the circle, holding an RC transmitter that remotely
controls the motor (via the ESC) and the elevator (via the servo). I
witnessed several flights and found the concept fascinating.
To make loops even tighter when flying CL combat, Bob came up
with a gimbaled
electric motor mount.
I would guess this
technique could work
with a single- and
double-control-line
setup.
As elevator
control is applied, the
motor actually pivots
up and down, which
greatly tightens any
loop maneuvers. The
airplane almost
pivots as if it were
held at both wingtips.
I’ve seen photos of
90 MODEL AVIATION
Underside of the single-line electric indoor CL aircraft. The
yellow timer (module) has been replaced by a Berg RC receiver.
Close-up of the motor gimbal mechanism Bob Wilder devised to
help tighten loop maneuvers during electric indoor CL combat.
Bill Schmidt’s rubber-powered Aeronca 15AC can be converted
to electric for flying indoors or outdoors in dead-calm weather.
Sombra Labs still sells the Lepton 5
single-conversion (crystal)-type receiver
for 50 MHz RC operation.
Bob flying combat with a friend, and it looks like it would be fun.
I’ve answered the “what” and the “how,” so now for the “where
can I buy these airplanes and the timer/control systems?” Bob has
several hobby manufacturers interested in these designs and would like
to sell them the production rights. In the meantime, he would love to
hear from you if you have an interest in this type of indoor flying.
Bob prefers phone calls; his number is (817) 498-6316. He wants to
assess the market potential, so please call him if you have an interest.
Q337: “I own several six-meter (50 MHz) RC receivers and have used
them successfully for several years now. Recently I went to buy
several more 50 MHz RC receivers and found they were no longer
available. Can you recommend any suppliers that I may have missed?”
A337: I’ll answer the source of supply question first, but read on
because I have more information about six-meter (50 MHz) RC
operation.
To my knowledge, Futaba and JR still sell RC transmitter
modules and receivers intended for 50 MHz operation. The 50
MHz transmitter modules can easily plug into most of their
transmitters.
You can purchase receivers separately. They are not the
smallest and lightest in weight by present-day standards. FMA
Direct offered its tiny M5 dual-conversion receivers on 50 MHz
several years back, but the supply has dried up.
The company was recently accepting special orders for a remaining
batch of 50 MHz receivers, but that offer ran out November 30, 2007. I
apologize for not getting that info out to my readers well before that
time. You still might want to contact FMA Direct, for a “favor.”
03sig3.QXD 1/25/08 10:15 AM Page 90I did notice on the RC Groups forum that
Jim Cob posted an article titled “Mini-
HowTo—Castle-Berg 50 MHz conversion.” It
describes his successful conversion of the
Castle Creations Berg four-channel MS4L
receiver to the 50 MHz Ham band.
I’ve read this, and you do have to know
what you are doing to accomplish this
conversion. You must also keep in mind that
once you dive into the receiver to make the
modification, you are essentially canceling the
original factory warranty. But those who are
so inclined now have the reference.
The best news came when I realized that a
Canadian RC manufacturer has been offering
several types of 50 MHz RC receivers. I
contacted Sombra Labs Inc. of Ottawa,
Ontario, and the company indicated that it still
has the Lepton 5 single-conversion (crystal)-
type receiver at 6.8 grams (0.24 ounce!) total
weight and the SL-8 synthesized dualconversion
receiver at 9 grams (0.32 ounce)
total weight.
Both of those receivers operate on the
Amateur Radio Service six-meter band (50
MHz). I believe the company also has
receivers on the original 53 MHz RC
channels.
I also understand that West Mountain
Radio, the company that makes that excellent
CBA II battery tester, will be distributing
Sombra Labs receivers in the US. Although
West Mountain Radio’s Web site shows only
72 MHz receivers at this time, the 50 MHz
receiver will have been added by the time you
read this.
With everyone fleeting to the new 2.4
GHz spread spectrum RC systems, one might
wonder why someone would still pursue sixmeter
RC flying. Even though you do share
your 50 MHz frequencies with other “Hams,”
I have been using the band since 1957 (my
call is W2QPP) and have never had a model
shot down or interfered with.
To legally fly RC on six meters, you must
hold a valid Amateur Radio Service license.
Until several years ago, to obtain that license
you were required to know Morse code at
least at five words per minute—both send and
receive. That requirement no longer applies.
All that is necessary is to pass a written test of
roughly 35 questions.
You can learn about the license
requirements, see sample tests, and learn how
to take the test by contacting the American
Radio Relay League (ARRL), located in
Newington, Connecticut. The ARRL is the
organizational equivalent of our AMA. There
is also a Web site to help you get a Ham radio
license. If you have any interest in pursing
six-meter RC operation, I suggest you look up
both sites.
For RC fliers who are properly licensed
and regularly use the six-meter amateur band,
your license is good for a 10-year period.
Make sure to check your expiration date. I just
looked and found that my general-class
license expires in May 2008.
If your license expires, you cannot legally
use the six-meter band to fly RC or enter
sanctioned AMA flying activities. Licenses
are always checked at these functions.
If your license needs to be renewed, you
can download a copy of Federal
Communications Commission (FCC) Form
605. It can be submitted only 90 days before
your license expires or as many as two years
after its expiration. I understand that you can
renew online. If you are beyond the two years,
you should contact the ARRL for further
instructions.
Q338: “Now that we are seeing so many
inexpensive micro size brushless electric
motors what do we do for micro size scale
aircraft?”
A338: I’m sure many micro-size ARF and
even RTF models will soon hit the hobby
market. For now I recommend those
wonderful laser-cut kits from Dumas
Products. They are available with wingspans
of 17, 24, and 30 inches.
For plans I strongly recommend the micro
rubber-powered designs from Bill Schmidt,
who is a noted modeler. Bill has had many
construction articles published in Flying
Models magazine through the years, and you
can purchase plans for those airplanes from
Carstens Publications.
Bill also has wonderful plans that he sells
direct. I recently bought micro-size scale plans
for an Aeronca 7AC Champion, a Piper PA-
11 on twin floats, and a Piper PA-16 Clipper.
All of Bill’s plans can be easily converted
from rubber-powered FF to electric-powered
RC. Write or call Bill Schmidt and request a
catalog listing of all his micro scale plans.
Please write in with your questions; that is
the only way we can keep this column format
going. When referring to published Q-and-As
(for follow-ups), provide the number as a
reference. MA
Sources:
American Radio Relay League
(860) 594-0200
www.arrl.org/
Bill Schmidt
4647 Krueger
Bel Air KS 67220
(316) 744-0378
Carstens Publications
(800) 474-6995
www.flying-models.com/
Dumas Products
(800) 458-2828
www.dumasestore.com/
FCC Form 605
(800) 418-3676
www.arrl.org/arrlvec/ncvec605-3.pdf
FMA Direct
(800) 343-2934
www.fmadirect.com
Ham license renewal
http://wireless.fcc.gov/services/index.htm?job
=cft&id=amateur&page=cft_renew
Ham radio license help
(860) 594-0200
www.hello-radio.org/
“Mini-HowTo—Castle-Berg 50 MHz
conversion”
www.rcgroups.com/forums/showthread.php?t
=608722
Sombra Labs
(613) 241-3818
www.sombralabs.com/products.php
West Mountain Radio
(203) 853-8080
www.westmountainradio.com/SombraRC.
htm
March 2008 91
03sig3.QXD 1/25/08 9:52 AM Page 91
Edition: Model Aviation - 2008/03
Page Numbers: 89,90,91
Edition: Model Aviation - 2008/03
Page Numbers: 89,90,91
Q336: “I’ve seen references in your column to electric powered
control line flying and the successes Bob Hunt has had with such
planes. But I heard recently that there is now a move towards indoor
electric powered control line flying.
“What can you tell me about this and whom might I contact for
more details?”
A336: One of the people who has been actively developing this
concept is Bob Wilder of Colleyville, Texas. He has been known for
years for his many indoor RC endurance records, but Bob has always
been fond of CL flying, and last year he put his talents to work on
some new concepts for indoor CL flying.
What Bob has come up with involves flying electric-powered CL
models from 27- and 32-foot lines in school gymnasiums and similar
indoor facilities. The beauty of doing this is that the airplanes are
constrained by the
lines they are
attached to; therefore,
they cannot go astray
and hit walls,
ceilings, or even
basketball hoops.
School gyms are
certainly more
available to modelers
than those massive
inflatable sports
domes.
The type of
Electric indoor CL flying
March 2008 89
? Frequently Asked Questions Bob Aberle | [email protected]
Also included in this column:
• Six-meter RC receivers
• Amateur radio licenses and
renewals
• Micro scale plans
Bob Wilder (L) flies electric CL combat with Rod Taylor in a
Texas school gym. These models won’t hit walls or the ceiling.
Underside of the two-line aircraft. The yellow item in heatshrink
wrap is the special timer discussed in the text.
Bob Wilder flies these two Shoestrings, at the top, and this
Buster in electric-powered indoor CL. All weigh 6-8 ounces.
03sig3.QXD 1/25/08 9:51 AM Page 89aircraft Bob is developing tends to weigh 6-8 ounces, powered by
brushless motors with input power of 30-50 watts. The models are
mostly made from Depron foam sheet material that, in many cases, is
reinforced with carbon-fiber tape.
I had been following the progress of Bob’s design efforts for the
past year. But I didn’t understand everything he was doing until I
witnessed his demonstration flying at the big JR Indoor Electric
Festival held in Columbus, Ohio, this past November. He is setting a
goal to develop indoor CL designs to fly in such categories as scale,
racing, combat, carrier, speed, stunt, and general sport.
Bob has come up with two interesting concepts, the first of which
employs conventional two-line control with the standard bellcrank that
operates the elevator (and sometimes coordinated flaps) on the aircraft.
In this configuration the brushless motor is controlled by an ESC that
is, in turn, attached to a special Multiple Function Electronic Timer
device that Bob is offering.
The timer can be programmed to time your flight and cut off power
before the battery begins to wear down. It also allows the user to adjust
the motor speed. This timer weighs only 3.2 grams and is certainly not
expensive.
Now comes the real fun! Some people have difficulty flying CL
because we get nauseated when turning rapidly in circles. Watching
gymnasium walls flash by might even exaggerate this condition. To
cope with that problem Bob came up with a single-control-line aircraft
that is tethered to a centrally located pylon.
The timer I referenced is unplugged, and in its place goes an RC
receiver (much like replacing a module) along with an RC servo. The
pilot stands outside the circle, holding an RC transmitter that remotely
controls the motor (via the ESC) and the elevator (via the servo). I
witnessed several flights and found the concept fascinating.
To make loops even tighter when flying CL combat, Bob came up
with a gimbaled
electric motor mount.
I would guess this
technique could work
with a single- and
double-control-line
setup.
As elevator
control is applied, the
motor actually pivots
up and down, which
greatly tightens any
loop maneuvers. The
airplane almost
pivots as if it were
held at both wingtips.
I’ve seen photos of
90 MODEL AVIATION
Underside of the single-line electric indoor CL aircraft. The
yellow timer (module) has been replaced by a Berg RC receiver.
Close-up of the motor gimbal mechanism Bob Wilder devised to
help tighten loop maneuvers during electric indoor CL combat.
Bill Schmidt’s rubber-powered Aeronca 15AC can be converted
to electric for flying indoors or outdoors in dead-calm weather.
Sombra Labs still sells the Lepton 5
single-conversion (crystal)-type receiver
for 50 MHz RC operation.
Bob flying combat with a friend, and it looks like it would be fun.
I’ve answered the “what” and the “how,” so now for the “where
can I buy these airplanes and the timer/control systems?” Bob has
several hobby manufacturers interested in these designs and would like
to sell them the production rights. In the meantime, he would love to
hear from you if you have an interest in this type of indoor flying.
Bob prefers phone calls; his number is (817) 498-6316. He wants to
assess the market potential, so please call him if you have an interest.
Q337: “I own several six-meter (50 MHz) RC receivers and have used
them successfully for several years now. Recently I went to buy
several more 50 MHz RC receivers and found they were no longer
available. Can you recommend any suppliers that I may have missed?”
A337: I’ll answer the source of supply question first, but read on
because I have more information about six-meter (50 MHz) RC
operation.
To my knowledge, Futaba and JR still sell RC transmitter
modules and receivers intended for 50 MHz operation. The 50
MHz transmitter modules can easily plug into most of their
transmitters.
You can purchase receivers separately. They are not the
smallest and lightest in weight by present-day standards. FMA
Direct offered its tiny M5 dual-conversion receivers on 50 MHz
several years back, but the supply has dried up.
The company was recently accepting special orders for a remaining
batch of 50 MHz receivers, but that offer ran out November 30, 2007. I
apologize for not getting that info out to my readers well before that
time. You still might want to contact FMA Direct, for a “favor.”
03sig3.QXD 1/25/08 10:15 AM Page 90I did notice on the RC Groups forum that
Jim Cob posted an article titled “Mini-
HowTo—Castle-Berg 50 MHz conversion.” It
describes his successful conversion of the
Castle Creations Berg four-channel MS4L
receiver to the 50 MHz Ham band.
I’ve read this, and you do have to know
what you are doing to accomplish this
conversion. You must also keep in mind that
once you dive into the receiver to make the
modification, you are essentially canceling the
original factory warranty. But those who are
so inclined now have the reference.
The best news came when I realized that a
Canadian RC manufacturer has been offering
several types of 50 MHz RC receivers. I
contacted Sombra Labs Inc. of Ottawa,
Ontario, and the company indicated that it still
has the Lepton 5 single-conversion (crystal)-
type receiver at 6.8 grams (0.24 ounce!) total
weight and the SL-8 synthesized dualconversion
receiver at 9 grams (0.32 ounce)
total weight.
Both of those receivers operate on the
Amateur Radio Service six-meter band (50
MHz). I believe the company also has
receivers on the original 53 MHz RC
channels.
I also understand that West Mountain
Radio, the company that makes that excellent
CBA II battery tester, will be distributing
Sombra Labs receivers in the US. Although
West Mountain Radio’s Web site shows only
72 MHz receivers at this time, the 50 MHz
receiver will have been added by the time you
read this.
With everyone fleeting to the new 2.4
GHz spread spectrum RC systems, one might
wonder why someone would still pursue sixmeter
RC flying. Even though you do share
your 50 MHz frequencies with other “Hams,”
I have been using the band since 1957 (my
call is W2QPP) and have never had a model
shot down or interfered with.
To legally fly RC on six meters, you must
hold a valid Amateur Radio Service license.
Until several years ago, to obtain that license
you were required to know Morse code at
least at five words per minute—both send and
receive. That requirement no longer applies.
All that is necessary is to pass a written test of
roughly 35 questions.
You can learn about the license
requirements, see sample tests, and learn how
to take the test by contacting the American
Radio Relay League (ARRL), located in
Newington, Connecticut. The ARRL is the
organizational equivalent of our AMA. There
is also a Web site to help you get a Ham radio
license. If you have any interest in pursing
six-meter RC operation, I suggest you look up
both sites.
For RC fliers who are properly licensed
and regularly use the six-meter amateur band,
your license is good for a 10-year period.
Make sure to check your expiration date. I just
looked and found that my general-class
license expires in May 2008.
If your license expires, you cannot legally
use the six-meter band to fly RC or enter
sanctioned AMA flying activities. Licenses
are always checked at these functions.
If your license needs to be renewed, you
can download a copy of Federal
Communications Commission (FCC) Form
605. It can be submitted only 90 days before
your license expires or as many as two years
after its expiration. I understand that you can
renew online. If you are beyond the two years,
you should contact the ARRL for further
instructions.
Q338: “Now that we are seeing so many
inexpensive micro size brushless electric
motors what do we do for micro size scale
aircraft?”
A338: I’m sure many micro-size ARF and
even RTF models will soon hit the hobby
market. For now I recommend those
wonderful laser-cut kits from Dumas
Products. They are available with wingspans
of 17, 24, and 30 inches.
For plans I strongly recommend the micro
rubber-powered designs from Bill Schmidt,
who is a noted modeler. Bill has had many
construction articles published in Flying
Models magazine through the years, and you
can purchase plans for those airplanes from
Carstens Publications.
Bill also has wonderful plans that he sells
direct. I recently bought micro-size scale plans
for an Aeronca 7AC Champion, a Piper PA-
11 on twin floats, and a Piper PA-16 Clipper.
All of Bill’s plans can be easily converted
from rubber-powered FF to electric-powered
RC. Write or call Bill Schmidt and request a
catalog listing of all his micro scale plans.
Please write in with your questions; that is
the only way we can keep this column format
going. When referring to published Q-and-As
(for follow-ups), provide the number as a
reference. MA
Sources:
American Radio Relay League
(860) 594-0200
www.arrl.org/
Bill Schmidt
4647 Krueger
Bel Air KS 67220
(316) 744-0378
Carstens Publications
(800) 474-6995
www.flying-models.com/
Dumas Products
(800) 458-2828
www.dumasestore.com/
FCC Form 605
(800) 418-3676
www.arrl.org/arrlvec/ncvec605-3.pdf
FMA Direct
(800) 343-2934
www.fmadirect.com
Ham license renewal
http://wireless.fcc.gov/services/index.htm?job
=cft&id=amateur&page=cft_renew
Ham radio license help
(860) 594-0200
www.hello-radio.org/
“Mini-HowTo—Castle-Berg 50 MHz
conversion”
www.rcgroups.com/forums/showthread.php?t
=608722
Sombra Labs
(613) 241-3818
www.sombralabs.com/products.php
West Mountain Radio
(203) 853-8080
www.westmountainradio.com/SombraRC.
htm
March 2008 91
03sig3.QXD 1/25/08 9:52 AM Page 91
Edition: Model Aviation - 2008/03
Page Numbers: 89,90,91
Q336: “I’ve seen references in your column to electric powered
control line flying and the successes Bob Hunt has had with such
planes. But I heard recently that there is now a move towards indoor
electric powered control line flying.
“What can you tell me about this and whom might I contact for
more details?”
A336: One of the people who has been actively developing this
concept is Bob Wilder of Colleyville, Texas. He has been known for
years for his many indoor RC endurance records, but Bob has always
been fond of CL flying, and last year he put his talents to work on
some new concepts for indoor CL flying.
What Bob has come up with involves flying electric-powered CL
models from 27- and 32-foot lines in school gymnasiums and similar
indoor facilities. The beauty of doing this is that the airplanes are
constrained by the
lines they are
attached to; therefore,
they cannot go astray
and hit walls,
ceilings, or even
basketball hoops.
School gyms are
certainly more
available to modelers
than those massive
inflatable sports
domes.
The type of
Electric indoor CL flying
March 2008 89
? Frequently Asked Questions Bob Aberle | [email protected]
Also included in this column:
• Six-meter RC receivers
• Amateur radio licenses and
renewals
• Micro scale plans
Bob Wilder (L) flies electric CL combat with Rod Taylor in a
Texas school gym. These models won’t hit walls or the ceiling.
Underside of the two-line aircraft. The yellow item in heatshrink
wrap is the special timer discussed in the text.
Bob Wilder flies these two Shoestrings, at the top, and this
Buster in electric-powered indoor CL. All weigh 6-8 ounces.
03sig3.QXD 1/25/08 9:51 AM Page 89aircraft Bob is developing tends to weigh 6-8 ounces, powered by
brushless motors with input power of 30-50 watts. The models are
mostly made from Depron foam sheet material that, in many cases, is
reinforced with carbon-fiber tape.
I had been following the progress of Bob’s design efforts for the
past year. But I didn’t understand everything he was doing until I
witnessed his demonstration flying at the big JR Indoor Electric
Festival held in Columbus, Ohio, this past November. He is setting a
goal to develop indoor CL designs to fly in such categories as scale,
racing, combat, carrier, speed, stunt, and general sport.
Bob has come up with two interesting concepts, the first of which
employs conventional two-line control with the standard bellcrank that
operates the elevator (and sometimes coordinated flaps) on the aircraft.
In this configuration the brushless motor is controlled by an ESC that
is, in turn, attached to a special Multiple Function Electronic Timer
device that Bob is offering.
The timer can be programmed to time your flight and cut off power
before the battery begins to wear down. It also allows the user to adjust
the motor speed. This timer weighs only 3.2 grams and is certainly not
expensive.
Now comes the real fun! Some people have difficulty flying CL
because we get nauseated when turning rapidly in circles. Watching
gymnasium walls flash by might even exaggerate this condition. To
cope with that problem Bob came up with a single-control-line aircraft
that is tethered to a centrally located pylon.
The timer I referenced is unplugged, and in its place goes an RC
receiver (much like replacing a module) along with an RC servo. The
pilot stands outside the circle, holding an RC transmitter that remotely
controls the motor (via the ESC) and the elevator (via the servo). I
witnessed several flights and found the concept fascinating.
To make loops even tighter when flying CL combat, Bob came up
with a gimbaled
electric motor mount.
I would guess this
technique could work
with a single- and
double-control-line
setup.
As elevator
control is applied, the
motor actually pivots
up and down, which
greatly tightens any
loop maneuvers. The
airplane almost
pivots as if it were
held at both wingtips.
I’ve seen photos of
90 MODEL AVIATION
Underside of the single-line electric indoor CL aircraft. The
yellow timer (module) has been replaced by a Berg RC receiver.
Close-up of the motor gimbal mechanism Bob Wilder devised to
help tighten loop maneuvers during electric indoor CL combat.
Bill Schmidt’s rubber-powered Aeronca 15AC can be converted
to electric for flying indoors or outdoors in dead-calm weather.
Sombra Labs still sells the Lepton 5
single-conversion (crystal)-type receiver
for 50 MHz RC operation.
Bob flying combat with a friend, and it looks like it would be fun.
I’ve answered the “what” and the “how,” so now for the “where
can I buy these airplanes and the timer/control systems?” Bob has
several hobby manufacturers interested in these designs and would like
to sell them the production rights. In the meantime, he would love to
hear from you if you have an interest in this type of indoor flying.
Bob prefers phone calls; his number is (817) 498-6316. He wants to
assess the market potential, so please call him if you have an interest.
Q337: “I own several six-meter (50 MHz) RC receivers and have used
them successfully for several years now. Recently I went to buy
several more 50 MHz RC receivers and found they were no longer
available. Can you recommend any suppliers that I may have missed?”
A337: I’ll answer the source of supply question first, but read on
because I have more information about six-meter (50 MHz) RC
operation.
To my knowledge, Futaba and JR still sell RC transmitter
modules and receivers intended for 50 MHz operation. The 50
MHz transmitter modules can easily plug into most of their
transmitters.
You can purchase receivers separately. They are not the
smallest and lightest in weight by present-day standards. FMA
Direct offered its tiny M5 dual-conversion receivers on 50 MHz
several years back, but the supply has dried up.
The company was recently accepting special orders for a remaining
batch of 50 MHz receivers, but that offer ran out November 30, 2007. I
apologize for not getting that info out to my readers well before that
time. You still might want to contact FMA Direct, for a “favor.”
03sig3.QXD 1/25/08 10:15 AM Page 90I did notice on the RC Groups forum that
Jim Cob posted an article titled “Mini-
HowTo—Castle-Berg 50 MHz conversion.” It
describes his successful conversion of the
Castle Creations Berg four-channel MS4L
receiver to the 50 MHz Ham band.
I’ve read this, and you do have to know
what you are doing to accomplish this
conversion. You must also keep in mind that
once you dive into the receiver to make the
modification, you are essentially canceling the
original factory warranty. But those who are
so inclined now have the reference.
The best news came when I realized that a
Canadian RC manufacturer has been offering
several types of 50 MHz RC receivers. I
contacted Sombra Labs Inc. of Ottawa,
Ontario, and the company indicated that it still
has the Lepton 5 single-conversion (crystal)-
type receiver at 6.8 grams (0.24 ounce!) total
weight and the SL-8 synthesized dualconversion
receiver at 9 grams (0.32 ounce)
total weight.
Both of those receivers operate on the
Amateur Radio Service six-meter band (50
MHz). I believe the company also has
receivers on the original 53 MHz RC
channels.
I also understand that West Mountain
Radio, the company that makes that excellent
CBA II battery tester, will be distributing
Sombra Labs receivers in the US. Although
West Mountain Radio’s Web site shows only
72 MHz receivers at this time, the 50 MHz
receiver will have been added by the time you
read this.
With everyone fleeting to the new 2.4
GHz spread spectrum RC systems, one might
wonder why someone would still pursue sixmeter
RC flying. Even though you do share
your 50 MHz frequencies with other “Hams,”
I have been using the band since 1957 (my
call is W2QPP) and have never had a model
shot down or interfered with.
To legally fly RC on six meters, you must
hold a valid Amateur Radio Service license.
Until several years ago, to obtain that license
you were required to know Morse code at
least at five words per minute—both send and
receive. That requirement no longer applies.
All that is necessary is to pass a written test of
roughly 35 questions.
You can learn about the license
requirements, see sample tests, and learn how
to take the test by contacting the American
Radio Relay League (ARRL), located in
Newington, Connecticut. The ARRL is the
organizational equivalent of our AMA. There
is also a Web site to help you get a Ham radio
license. If you have any interest in pursing
six-meter RC operation, I suggest you look up
both sites.
For RC fliers who are properly licensed
and regularly use the six-meter amateur band,
your license is good for a 10-year period.
Make sure to check your expiration date. I just
looked and found that my general-class
license expires in May 2008.
If your license expires, you cannot legally
use the six-meter band to fly RC or enter
sanctioned AMA flying activities. Licenses
are always checked at these functions.
If your license needs to be renewed, you
can download a copy of Federal
Communications Commission (FCC) Form
605. It can be submitted only 90 days before
your license expires or as many as two years
after its expiration. I understand that you can
renew online. If you are beyond the two years,
you should contact the ARRL for further
instructions.
Q338: “Now that we are seeing so many
inexpensive micro size brushless electric
motors what do we do for micro size scale
aircraft?”
A338: I’m sure many micro-size ARF and
even RTF models will soon hit the hobby
market. For now I recommend those
wonderful laser-cut kits from Dumas
Products. They are available with wingspans
of 17, 24, and 30 inches.
For plans I strongly recommend the micro
rubber-powered designs from Bill Schmidt,
who is a noted modeler. Bill has had many
construction articles published in Flying
Models magazine through the years, and you
can purchase plans for those airplanes from
Carstens Publications.
Bill also has wonderful plans that he sells
direct. I recently bought micro-size scale plans
for an Aeronca 7AC Champion, a Piper PA-
11 on twin floats, and a Piper PA-16 Clipper.
All of Bill’s plans can be easily converted
from rubber-powered FF to electric-powered
RC. Write or call Bill Schmidt and request a
catalog listing of all his micro scale plans.
Please write in with your questions; that is
the only way we can keep this column format
going. When referring to published Q-and-As
(for follow-ups), provide the number as a
reference. MA
Sources:
American Radio Relay League
(860) 594-0200
www.arrl.org/
Bill Schmidt
4647 Krueger
Bel Air KS 67220
(316) 744-0378
Carstens Publications
(800) 474-6995
www.flying-models.com/
Dumas Products
(800) 458-2828
www.dumasestore.com/
FCC Form 605
(800) 418-3676
www.arrl.org/arrlvec/ncvec605-3.pdf
FMA Direct
(800) 343-2934
www.fmadirect.com
Ham license renewal
http://wireless.fcc.gov/services/index.htm?job
=cft&id=amateur&page=cft_renew
Ham radio license help
(860) 594-0200
www.hello-radio.org/
“Mini-HowTo—Castle-Berg 50 MHz
conversion”
www.rcgroups.com/forums/showthread.php?t
=608722
Sombra Labs
(613) 241-3818
www.sombralabs.com/products.php
West Mountain Radio
(203) 853-8080
www.westmountainradio.com/SombraRC.
htm
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