Also included in this column:
• New glow Pattern propellers
• Ultra-RC’s new “Professional
Series” Evolution
• Update on Radio South
glow-driver modifications
Above: Bryan Kennedy has a well-earned
reputation for a great finish on his
airplane.
Left: Bryan Kennedy (Atlanta GA) shows
off his Ultra-RC Evolution.
The author’s new Ultra-RC Evolution 2-meter Pattern model with an O.S. 1.60 FX
engine.
MOST OF THE ARFs I build/assemble
come with pin-hinged, plastic-stick, or
even metal hinges. I like to swap out the
supplied hinges and replace them with
Mylar hinges.
RC Aerobatics (Pattern) airplanes use
relatively small control throws, which are
typically in the range of 10°-15°. Mylar
hinges handle this movement easily and
have no “play” when the control surface is
at center. They also seem to reduce the
“complaining” we often hear from digital
servos when holding a control surface at
center/neutral.
Central Hobbies markets a neat hingemarking
tool that enables you to make
“close to perfect” hinge-slot alignment on
straight, beveled, and tapered control
surfaces. As is often the case, a Patternmodel
builder will find a way to improve
upon any device within his or her reach.
Keith Hoard sent me a picture of the
modification he made to this hinge tool.
Keith added an extra guide bar. His
January 2007 103
A modification by Keith Hoard allows the user to go straight to
cutting the slot.
Central Hobbies’ flexible hinge-alignment tool works well on
tapered and beveled control surfaces.
Eric owed people this photo of where you take the voltage tap on a
Radio South glow driver for an I4C LCD or an LED warning light.
change allows the guide to be used in conjunction with a cutting
tool. (His version could be a knife or a motorized hinge-slot
tool.) His system lets you cut without even having to mark the
slot. This is a neat idea and a time saver!
Mike Harrison sent me a couple APC 18 x 10.1 narrow-blade
and wide-blade propellers that considerably slow a glowpowered
Pattern airplane and give a close rendition of the
performance you can get with a big electric motor.
I had the chance to use these propellers at the 2006 Nats. I
could immediately feel and see the advantage on my O.S. 1.60
engine. The up-lines were no problem at all, and the down-lines
were magic. Mike ran a huge 19 x 8 on his airplane this year,
and you could see the smooth and consistent speed control he
had throughout his flights.
The word is that we will see many of the big names
migrating back to glow power this coming year. YS 1.60s have
power to spare, and 1.70 versions were being run at the Pattern
World Championships. O.S. has, so I am told, a 2.00 four-stroke
with a computerized fuel-injection system.
Many of the pilots who flew and got used to the electricpower
curve may be looking to the work Mike has done to find
the correct propeller formula for their new 2007 configurations.
Those of us with more modest budgets may well know that
Ultra-RC has brought us the Icepoint and Quest ARFs. The
company’s latest Pattern offering is the Evolution: an ARF that
was specifically designed to be a competition Pattern airplane.
The Evolution is part of Ultra-RC’s “Professional Series.” Its
specifications are: wingspan, 77 inches; total length, 78 inches;
wing area, 1,025 square inches; ready-to-fly weight, 9.0-10.5
pounds.
The company feels that this design has incorporated new and
perhaps “revolutionary” construction techniques compared to
what is seen in today’s ARFs. These methods bring us an
economical balsa-and-plywood model with the features of a
composite-built ARF. Ultra-RC believes this raises its ARFs to
a new level of quality and a much higher level of completion.
The Evolution’s construction is strong and light. The wings
and stabilizer feature a built-up two-piece design. The
stabilizers are removable for transport/shipping, etc. and are
designed to contain one full-size servo each.
Carbon-fiber wing and stabilizer tubes are used with all the
incidences preset for you at the factory. In addition, Ultra-RC’s
Professional Series features an adjustable back-and-forth-sliding
wing installation that allows you to adjust the CG without
adding weight.
To make changes and repairs easy, the Evolution’s covering
is Oracover (UltraCote). The cowl and wheel pants are
prepainted fiberglass. The canopy is removable with a factoryinstalled
spring-clip mechanism that works extremely well.
The landing gear is a bit different from the more
conventional designs we have been used to. It is made from a
carbon-fiber tube and sleeve. The legs are covered with light
airfoil-shaped fairings. The landing-gear legs fit into sleeves that
are triple-bearing supported and glued into the fuselage. The
model comes with a tuned-pipe channel already built in. The
carbon-fiber legs are designed to form a sort of “A” frame on
either side of the tunnel.
You can use Ultra-RC’s engine mount, but it is no problem to
fit a soft mount such as the new Type C Hyde Mount. The engine
box has a flat-faced firewall, which leaves you with plenty of
options.
Electric conversion is not required! The Ultra-RC Evolution
was designed from the outset with the growing numbers of
Electric-power modelers in mind. An electric motor mount is
available when you order the airplane. The battery tray is already
designed so it will mount in the tuned-pipe tunnel, thus providing
fresh air for external cooling.
The Evolution is a fairly complete ARF that includes all the
necessary hardware such as pushrods, landing gear, wheels, and a
photo-illustrated instruction manual. It has a full set of ball-joint
clevises and pull-pull hardware. This model requires a 1.20- to
1.60-size two- or equivalent four-stroke engine and a tuned
pipe/muffler. You need to provide your own 3-inch FAI spinner.
Ultra-RC recommends that you use five high-torque servos
rated at roughly 90 ounces on 4.8 volts for the main control
surfaces. A higher-torque servo may be substituted for the pullpull
system, and one standard servo may be used for the throttle.
I have put together a couple Evolutions. The only
modification I made on the second one was to shorten the landing
gear. The legs supplied may be good for those 24-inch electric
propellers, but they worked fine for the
O.S. 1.60 17-inch propellers after I
removed 2.5 inches.
My first build came out at 10 pounds, 9
ounces, and my second one came out at 10
pounds, 6.3 ounces, with a 2500 mAh Li-
Poly receiver pack, O.S. 1.60 FX, Karl
Mueller header, and ES medium-length,
carbon-fiber, 1.40 tuned pipe. The airplane
goes vertical on half-throttle stick and is
fully capable of doing all the F3A
schedules.
No sooner than I had posted pictures of
my model, Bryan Kennedy sent me some
photos of his version. At first I did not
recognize the airplane; it is amazing how
just changing a few colors or patterns can
make a model look so different. Bryan’s
level of detail is way beyond any of my
efforts.
His version of the Ultra-RC Evolution
ARF came out at 9 pounds, 13 ounces.
That makes it a great home for his O.S.
1.40 RX.
Bryan reports that his model has
spectacular vertical performance (no
surprise there!) and nimble snaps that stop
immediately. I found little or no coupling
in the knife edge, depending on where I
set the CG.
The up-lines are straight, but at full
throttle I had to add slight right rudder.
My JR radio lets me dial 2% of right
rudder on only the last two clicks of the
throttle ratchet. Once programmed, you
can forget about needing anymore rudder
correction on the up-lines.
The down-line needed 1% of downelevator
at low throttle to get a perfect
down-line with hands off the controls.
The knife-edge was strong and I reduced
the rudder to low rate for the snaps and
the spins.
You have to go easy on the elevator
when entering the spin or you may cause
the “break” to occur too soon. It is a
pronounced break and will leave the
judge with no doubt that you did a stalled
entry into the spin.
Awhile ago I included pictures of my
modification to the old Radio South glow
driver. It was the orange-cased one with
an external on/off switch—not the
version with a self-timer button. The
“upgrade” included swapping in a fivecell
Ni-Cd or NiMH 2000-3000 mAh
pack. It also showed a bright LED or a
I4C LCD voltage display. What I omitted
was where to take a voltage tap on the
unit for these indicators.
In the photo of the opened-up glow
driver, you can see the main circuit
board. At the bottom of the photo you
can see the back of a small voltage meter.
There are two wires soldered to the
terminals of this voltage meter: one
positive (red) and one negative (black).
The black wire is used as the negative
voltage tap and goes to the common
negative-wire position on the circuit
board.
The red wire is the positive voltage
tap and goes to the position shown near
the top left-hand side of the photo of the
board. This part of the circuit is switched
on and off by the external switch; that
way you only get a reading to the
voltmeter or bright LED when it is
switched on. (Central Hobbies has a good
LED that works well in this for this
application.) That indicates that the unit
is on but does not indicate any activity at
the glow-plug end of the unit.
The level of glow-plug activity is still
indicated by the bank of green LEDs
when attached to a glow plug. It is not
commonly known that the green LEDs
can show, for instance, the usual three
green lights and still not be actually
lighting the glow plug. A voltage meter
will tell you what is available from the
battery.
When the battery is under the load of
the glow plug, the meter tells you if there
is enough voltage. If it is reading a
number such as 4.6 volts, there is a good
chance that the glow plug is not actually
lit. The voltage meter also gives you a
quick visual check indicating how soon
you will need to recharge the unit.
Back to the building board!
Edition: Model Aviation - 2007/01
Page Numbers: 102,103,104
Edition: Model Aviation - 2007/01
Page Numbers: 102,103,104
Also included in this column:
• New glow Pattern propellers
• Ultra-RC’s new “Professional
Series” Evolution
• Update on Radio South
glow-driver modifications
Above: Bryan Kennedy has a well-earned
reputation for a great finish on his
airplane.
Left: Bryan Kennedy (Atlanta GA) shows
off his Ultra-RC Evolution.
The author’s new Ultra-RC Evolution 2-meter Pattern model with an O.S. 1.60 FX
engine.
MOST OF THE ARFs I build/assemble
come with pin-hinged, plastic-stick, or
even metal hinges. I like to swap out the
supplied hinges and replace them with
Mylar hinges.
RC Aerobatics (Pattern) airplanes use
relatively small control throws, which are
typically in the range of 10°-15°. Mylar
hinges handle this movement easily and
have no “play” when the control surface is
at center. They also seem to reduce the
“complaining” we often hear from digital
servos when holding a control surface at
center/neutral.
Central Hobbies markets a neat hingemarking
tool that enables you to make
“close to perfect” hinge-slot alignment on
straight, beveled, and tapered control
surfaces. As is often the case, a Patternmodel
builder will find a way to improve
upon any device within his or her reach.
Keith Hoard sent me a picture of the
modification he made to this hinge tool.
Keith added an extra guide bar. His
January 2007 103
A modification by Keith Hoard allows the user to go straight to
cutting the slot.
Central Hobbies’ flexible hinge-alignment tool works well on
tapered and beveled control surfaces.
Eric owed people this photo of where you take the voltage tap on a
Radio South glow driver for an I4C LCD or an LED warning light.
change allows the guide to be used in conjunction with a cutting
tool. (His version could be a knife or a motorized hinge-slot
tool.) His system lets you cut without even having to mark the
slot. This is a neat idea and a time saver!
Mike Harrison sent me a couple APC 18 x 10.1 narrow-blade
and wide-blade propellers that considerably slow a glowpowered
Pattern airplane and give a close rendition of the
performance you can get with a big electric motor.
I had the chance to use these propellers at the 2006 Nats. I
could immediately feel and see the advantage on my O.S. 1.60
engine. The up-lines were no problem at all, and the down-lines
were magic. Mike ran a huge 19 x 8 on his airplane this year,
and you could see the smooth and consistent speed control he
had throughout his flights.
The word is that we will see many of the big names
migrating back to glow power this coming year. YS 1.60s have
power to spare, and 1.70 versions were being run at the Pattern
World Championships. O.S. has, so I am told, a 2.00 four-stroke
with a computerized fuel-injection system.
Many of the pilots who flew and got used to the electricpower
curve may be looking to the work Mike has done to find
the correct propeller formula for their new 2007 configurations.
Those of us with more modest budgets may well know that
Ultra-RC has brought us the Icepoint and Quest ARFs. The
company’s latest Pattern offering is the Evolution: an ARF that
was specifically designed to be a competition Pattern airplane.
The Evolution is part of Ultra-RC’s “Professional Series.” Its
specifications are: wingspan, 77 inches; total length, 78 inches;
wing area, 1,025 square inches; ready-to-fly weight, 9.0-10.5
pounds.
The company feels that this design has incorporated new and
perhaps “revolutionary” construction techniques compared to
what is seen in today’s ARFs. These methods bring us an
economical balsa-and-plywood model with the features of a
composite-built ARF. Ultra-RC believes this raises its ARFs to
a new level of quality and a much higher level of completion.
The Evolution’s construction is strong and light. The wings
and stabilizer feature a built-up two-piece design. The
stabilizers are removable for transport/shipping, etc. and are
designed to contain one full-size servo each.
Carbon-fiber wing and stabilizer tubes are used with all the
incidences preset for you at the factory. In addition, Ultra-RC’s
Professional Series features an adjustable back-and-forth-sliding
wing installation that allows you to adjust the CG without
adding weight.
To make changes and repairs easy, the Evolution’s covering
is Oracover (UltraCote). The cowl and wheel pants are
prepainted fiberglass. The canopy is removable with a factoryinstalled
spring-clip mechanism that works extremely well.
The landing gear is a bit different from the more
conventional designs we have been used to. It is made from a
carbon-fiber tube and sleeve. The legs are covered with light
airfoil-shaped fairings. The landing-gear legs fit into sleeves that
are triple-bearing supported and glued into the fuselage. The
model comes with a tuned-pipe channel already built in. The
carbon-fiber legs are designed to form a sort of “A” frame on
either side of the tunnel.
You can use Ultra-RC’s engine mount, but it is no problem to
fit a soft mount such as the new Type C Hyde Mount. The engine
box has a flat-faced firewall, which leaves you with plenty of
options.
Electric conversion is not required! The Ultra-RC Evolution
was designed from the outset with the growing numbers of
Electric-power modelers in mind. An electric motor mount is
available when you order the airplane. The battery tray is already
designed so it will mount in the tuned-pipe tunnel, thus providing
fresh air for external cooling.
The Evolution is a fairly complete ARF that includes all the
necessary hardware such as pushrods, landing gear, wheels, and a
photo-illustrated instruction manual. It has a full set of ball-joint
clevises and pull-pull hardware. This model requires a 1.20- to
1.60-size two- or equivalent four-stroke engine and a tuned
pipe/muffler. You need to provide your own 3-inch FAI spinner.
Ultra-RC recommends that you use five high-torque servos
rated at roughly 90 ounces on 4.8 volts for the main control
surfaces. A higher-torque servo may be substituted for the pullpull
system, and one standard servo may be used for the throttle.
I have put together a couple Evolutions. The only
modification I made on the second one was to shorten the landing
gear. The legs supplied may be good for those 24-inch electric
propellers, but they worked fine for the
O.S. 1.60 17-inch propellers after I
removed 2.5 inches.
My first build came out at 10 pounds, 9
ounces, and my second one came out at 10
pounds, 6.3 ounces, with a 2500 mAh Li-
Poly receiver pack, O.S. 1.60 FX, Karl
Mueller header, and ES medium-length,
carbon-fiber, 1.40 tuned pipe. The airplane
goes vertical on half-throttle stick and is
fully capable of doing all the F3A
schedules.
No sooner than I had posted pictures of
my model, Bryan Kennedy sent me some
photos of his version. At first I did not
recognize the airplane; it is amazing how
just changing a few colors or patterns can
make a model look so different. Bryan’s
level of detail is way beyond any of my
efforts.
His version of the Ultra-RC Evolution
ARF came out at 9 pounds, 13 ounces.
That makes it a great home for his O.S.
1.40 RX.
Bryan reports that his model has
spectacular vertical performance (no
surprise there!) and nimble snaps that stop
immediately. I found little or no coupling
in the knife edge, depending on where I
set the CG.
The up-lines are straight, but at full
throttle I had to add slight right rudder.
My JR radio lets me dial 2% of right
rudder on only the last two clicks of the
throttle ratchet. Once programmed, you
can forget about needing anymore rudder
correction on the up-lines.
The down-line needed 1% of downelevator
at low throttle to get a perfect
down-line with hands off the controls.
The knife-edge was strong and I reduced
the rudder to low rate for the snaps and
the spins.
You have to go easy on the elevator
when entering the spin or you may cause
the “break” to occur too soon. It is a
pronounced break and will leave the
judge with no doubt that you did a stalled
entry into the spin.
Awhile ago I included pictures of my
modification to the old Radio South glow
driver. It was the orange-cased one with
an external on/off switch—not the
version with a self-timer button. The
“upgrade” included swapping in a fivecell
Ni-Cd or NiMH 2000-3000 mAh
pack. It also showed a bright LED or a
I4C LCD voltage display. What I omitted
was where to take a voltage tap on the
unit for these indicators.
In the photo of the opened-up glow
driver, you can see the main circuit
board. At the bottom of the photo you
can see the back of a small voltage meter.
There are two wires soldered to the
terminals of this voltage meter: one
positive (red) and one negative (black).
The black wire is used as the negative
voltage tap and goes to the common
negative-wire position on the circuit
board.
The red wire is the positive voltage
tap and goes to the position shown near
the top left-hand side of the photo of the
board. This part of the circuit is switched
on and off by the external switch; that
way you only get a reading to the
voltmeter or bright LED when it is
switched on. (Central Hobbies has a good
LED that works well in this for this
application.) That indicates that the unit
is on but does not indicate any activity at
the glow-plug end of the unit.
The level of glow-plug activity is still
indicated by the bank of green LEDs
when attached to a glow plug. It is not
commonly known that the green LEDs
can show, for instance, the usual three
green lights and still not be actually
lighting the glow plug. A voltage meter
will tell you what is available from the
battery.
When the battery is under the load of
the glow plug, the meter tells you if there
is enough voltage. If it is reading a
number such as 4.6 volts, there is a good
chance that the glow plug is not actually
lit. The voltage meter also gives you a
quick visual check indicating how soon
you will need to recharge the unit.
Back to the building board!
Edition: Model Aviation - 2007/01
Page Numbers: 102,103,104
Also included in this column:
• New glow Pattern propellers
• Ultra-RC’s new “Professional
Series” Evolution
• Update on Radio South
glow-driver modifications
Above: Bryan Kennedy has a well-earned
reputation for a great finish on his
airplane.
Left: Bryan Kennedy (Atlanta GA) shows
off his Ultra-RC Evolution.
The author’s new Ultra-RC Evolution 2-meter Pattern model with an O.S. 1.60 FX
engine.
MOST OF THE ARFs I build/assemble
come with pin-hinged, plastic-stick, or
even metal hinges. I like to swap out the
supplied hinges and replace them with
Mylar hinges.
RC Aerobatics (Pattern) airplanes use
relatively small control throws, which are
typically in the range of 10°-15°. Mylar
hinges handle this movement easily and
have no “play” when the control surface is
at center. They also seem to reduce the
“complaining” we often hear from digital
servos when holding a control surface at
center/neutral.
Central Hobbies markets a neat hingemarking
tool that enables you to make
“close to perfect” hinge-slot alignment on
straight, beveled, and tapered control
surfaces. As is often the case, a Patternmodel
builder will find a way to improve
upon any device within his or her reach.
Keith Hoard sent me a picture of the
modification he made to this hinge tool.
Keith added an extra guide bar. His
January 2007 103
A modification by Keith Hoard allows the user to go straight to
cutting the slot.
Central Hobbies’ flexible hinge-alignment tool works well on
tapered and beveled control surfaces.
Eric owed people this photo of where you take the voltage tap on a
Radio South glow driver for an I4C LCD or an LED warning light.
change allows the guide to be used in conjunction with a cutting
tool. (His version could be a knife or a motorized hinge-slot
tool.) His system lets you cut without even having to mark the
slot. This is a neat idea and a time saver!
Mike Harrison sent me a couple APC 18 x 10.1 narrow-blade
and wide-blade propellers that considerably slow a glowpowered
Pattern airplane and give a close rendition of the
performance you can get with a big electric motor.
I had the chance to use these propellers at the 2006 Nats. I
could immediately feel and see the advantage on my O.S. 1.60
engine. The up-lines were no problem at all, and the down-lines
were magic. Mike ran a huge 19 x 8 on his airplane this year,
and you could see the smooth and consistent speed control he
had throughout his flights.
The word is that we will see many of the big names
migrating back to glow power this coming year. YS 1.60s have
power to spare, and 1.70 versions were being run at the Pattern
World Championships. O.S. has, so I am told, a 2.00 four-stroke
with a computerized fuel-injection system.
Many of the pilots who flew and got used to the electricpower
curve may be looking to the work Mike has done to find
the correct propeller formula for their new 2007 configurations.
Those of us with more modest budgets may well know that
Ultra-RC has brought us the Icepoint and Quest ARFs. The
company’s latest Pattern offering is the Evolution: an ARF that
was specifically designed to be a competition Pattern airplane.
The Evolution is part of Ultra-RC’s “Professional Series.” Its
specifications are: wingspan, 77 inches; total length, 78 inches;
wing area, 1,025 square inches; ready-to-fly weight, 9.0-10.5
pounds.
The company feels that this design has incorporated new and
perhaps “revolutionary” construction techniques compared to
what is seen in today’s ARFs. These methods bring us an
economical balsa-and-plywood model with the features of a
composite-built ARF. Ultra-RC believes this raises its ARFs to
a new level of quality and a much higher level of completion.
The Evolution’s construction is strong and light. The wings
and stabilizer feature a built-up two-piece design. The
stabilizers are removable for transport/shipping, etc. and are
designed to contain one full-size servo each.
Carbon-fiber wing and stabilizer tubes are used with all the
incidences preset for you at the factory. In addition, Ultra-RC’s
Professional Series features an adjustable back-and-forth-sliding
wing installation that allows you to adjust the CG without
adding weight.
To make changes and repairs easy, the Evolution’s covering
is Oracover (UltraCote). The cowl and wheel pants are
prepainted fiberglass. The canopy is removable with a factoryinstalled
spring-clip mechanism that works extremely well.
The landing gear is a bit different from the more
conventional designs we have been used to. It is made from a
carbon-fiber tube and sleeve. The legs are covered with light
airfoil-shaped fairings. The landing-gear legs fit into sleeves that
are triple-bearing supported and glued into the fuselage. The
model comes with a tuned-pipe channel already built in. The
carbon-fiber legs are designed to form a sort of “A” frame on
either side of the tunnel.
You can use Ultra-RC’s engine mount, but it is no problem to
fit a soft mount such as the new Type C Hyde Mount. The engine
box has a flat-faced firewall, which leaves you with plenty of
options.
Electric conversion is not required! The Ultra-RC Evolution
was designed from the outset with the growing numbers of
Electric-power modelers in mind. An electric motor mount is
available when you order the airplane. The battery tray is already
designed so it will mount in the tuned-pipe tunnel, thus providing
fresh air for external cooling.
The Evolution is a fairly complete ARF that includes all the
necessary hardware such as pushrods, landing gear, wheels, and a
photo-illustrated instruction manual. It has a full set of ball-joint
clevises and pull-pull hardware. This model requires a 1.20- to
1.60-size two- or equivalent four-stroke engine and a tuned
pipe/muffler. You need to provide your own 3-inch FAI spinner.
Ultra-RC recommends that you use five high-torque servos
rated at roughly 90 ounces on 4.8 volts for the main control
surfaces. A higher-torque servo may be substituted for the pullpull
system, and one standard servo may be used for the throttle.
I have put together a couple Evolutions. The only
modification I made on the second one was to shorten the landing
gear. The legs supplied may be good for those 24-inch electric
propellers, but they worked fine for the
O.S. 1.60 17-inch propellers after I
removed 2.5 inches.
My first build came out at 10 pounds, 9
ounces, and my second one came out at 10
pounds, 6.3 ounces, with a 2500 mAh Li-
Poly receiver pack, O.S. 1.60 FX, Karl
Mueller header, and ES medium-length,
carbon-fiber, 1.40 tuned pipe. The airplane
goes vertical on half-throttle stick and is
fully capable of doing all the F3A
schedules.
No sooner than I had posted pictures of
my model, Bryan Kennedy sent me some
photos of his version. At first I did not
recognize the airplane; it is amazing how
just changing a few colors or patterns can
make a model look so different. Bryan’s
level of detail is way beyond any of my
efforts.
His version of the Ultra-RC Evolution
ARF came out at 9 pounds, 13 ounces.
That makes it a great home for his O.S.
1.40 RX.
Bryan reports that his model has
spectacular vertical performance (no
surprise there!) and nimble snaps that stop
immediately. I found little or no coupling
in the knife edge, depending on where I
set the CG.
The up-lines are straight, but at full
throttle I had to add slight right rudder.
My JR radio lets me dial 2% of right
rudder on only the last two clicks of the
throttle ratchet. Once programmed, you
can forget about needing anymore rudder
correction on the up-lines.
The down-line needed 1% of downelevator
at low throttle to get a perfect
down-line with hands off the controls.
The knife-edge was strong and I reduced
the rudder to low rate for the snaps and
the spins.
You have to go easy on the elevator
when entering the spin or you may cause
the “break” to occur too soon. It is a
pronounced break and will leave the
judge with no doubt that you did a stalled
entry into the spin.
Awhile ago I included pictures of my
modification to the old Radio South glow
driver. It was the orange-cased one with
an external on/off switch—not the
version with a self-timer button. The
“upgrade” included swapping in a fivecell
Ni-Cd or NiMH 2000-3000 mAh
pack. It also showed a bright LED or a
I4C LCD voltage display. What I omitted
was where to take a voltage tap on the
unit for these indicators.
In the photo of the opened-up glow
driver, you can see the main circuit
board. At the bottom of the photo you
can see the back of a small voltage meter.
There are two wires soldered to the
terminals of this voltage meter: one
positive (red) and one negative (black).
The black wire is used as the negative
voltage tap and goes to the common
negative-wire position on the circuit
board.
The red wire is the positive voltage
tap and goes to the position shown near
the top left-hand side of the photo of the
board. This part of the circuit is switched
on and off by the external switch; that
way you only get a reading to the
voltmeter or bright LED when it is
switched on. (Central Hobbies has a good
LED that works well in this for this
application.) That indicates that the unit
is on but does not indicate any activity at
the glow-plug end of the unit.
The level of glow-plug activity is still
indicated by the bank of green LEDs
when attached to a glow plug. It is not
commonly known that the green LEDs
can show, for instance, the usual three
green lights and still not be actually
lighting the glow plug. A voltage meter
will tell you what is available from the
battery.
When the battery is under the load of
the glow plug, the meter tells you if there
is enough voltage. If it is reading a
number such as 4.6 volts, there is a good
chance that the glow plug is not actually
lit. The voltage meter also gives you a
quick visual check indicating how soon
you will need to recharge the unit.
Back to the building board!