THIS IS MY 31st
monthly column in
which I try to give
you the best possible
answers to questions
you have written or
E-mailed to me.
Each new question is
given a sequential number for identification purposes.
Until the August 2005 column this material had appeared in
the pages of MA, and additional questions and answers had been
posted on a special section of the AMA Web site (www.modelair
craft.org). That Web page is now in the process of being revised and,
as such, there will be no new postings in the foreseeable future.
What you read each month in print is all you will see. I will advise
you when we are able to return to the original format. The original
“search process” by categories will also be suspended until the posting
is back online.
In the meantime, I’m available to help you locate specific subjects
of interest. Just drop me an E-mail. Also please keep sending in your
questions; that’s the only way I can continue to provide this service to
readers.
Q251: “I’m very new to the hobby and I’m not sure what kind of field
support equipment I need to be able to fuel and start my glow engine.”
A251: Before answering this question I looked at several catalogs
from the major mail-order suppliers to see what type of field support
equipment is available for the modeler. It is amazing that such a
What are the basic field support equipment needs for the newcomer?
October 2006 79
? Frequently Asked Questions Bob Aberle | [email protected]
Also included in this column:
• Return of the Mighty Midget?
• ESCs and Li-Poly batteries
• Is Li-Poly break-in really
necessary?
Components of the Du-Bro Fillin’ Station flightline fuel caddy. Everything is basically
attached to the top of a 1-gallon fuel bottle.
A separate charger is supplied to charge single Ni-Cd cell inside
Glo-Plug Ignitor. This takes overnight to fully charge.
Fillin’ Station mounted to top of fuel
bottle. Separate caddy is supplied to hold
Glo-Plug Ignitor (in Bob’s hand).
10sig3.QXD 8/24/06 10:18 AM Page 79variety of equipment exists. It must be bewildering to the hobby
newcomer.
I’m sure your local hobby shop will gladly set you up with all the
right items. I will tell you what I use and why I use it, but recognize
that there are many different answers to this reader’s question.
The basic needs for fueling and starting a glow engine involve
filling the fuel tank, lighting (or powering) the glow plug located at the
top of the engine’s cylinder head, and flipping or turning the propeller
over until the engine fires (starts).
Some modelers favor a field kit with a power panel that provides
power distribution from a single 12-volt battery to an electric fuel
pump, to a glow-plug lighter, and to a starter motor to turn over the
propeller. This is a good concept because you need only one 12-volt
gelled cell battery to power everything. Thus only one battery has to
be charged before venturing out to the flying field.
Using an electric fuel pump is fast and easy. However, if you don’t
stop the pump in time (or leave it running and walk away), you can
80 MODEL AVIATION
Popular Castle Creations brushless ESCs. Phoenix-10 can be
programmed with aid of PC. Thunderbird-18 will detect cell count
and set low-voltage cutoff accordingly.
The modern Mighty Midget Gold Series outrunner motor weighs
less than 7 grams and can fly a 3- to 6-ounce model.
Ignitor clips directly to glow plug located
on top of engine. Shown is rare Cooney .61
designed and built by Fourmost Racing
Products’ Ralph Cooney. It never went
into production. Mighty Midget motor/actuator as used in the 1950s. MA Associate Editor Michael Ramsey
found it in the AMA National Model Aviation Museum and took this photo.
easily overflow fuel onto the ground. Environmentalists don’t like
seeing fuel spilled on the ground since it can affect the ground water.
In addition to that problem, you will need separate cables running
up to the glow plug and to your starter motor. That results in a lot of
wire hanging off your field kit.
My approach to field equipment is different; I chose the Du-Bro
catalog number 907 Fillin’ Station flightline fuel caddy (http://dub
ro.com/hobby/). It is made from a molded plastic that is not
affected by glow fuel or gasoline.
The main bracket basically mounts on top of your 1-gallon fuel
bottle, in place of the normal cap. To this bracket a manual (hand
crank) fuel pump is attached. There are provisions for several tools,
and a four-way socket wrench is included. This wrench will remove
glow plugs and tighten prop nuts. There is also room for two extra
glow plugs since they burn out quite often.
A Du-Bro Kwik Start Glo-Plug Ignitor is provided, along with a
10sig3.QXD 8/24/06 10:21 AM Page 80suitable charger. There is a caddy on the
bracket on which to stow the ignitor when it’s
not in use.
Fuel tubing is also supplied. One length
goes inside the cap and runs to the bottom of
the fuel bottle. A filter is placed on the end of
that line. Another length of tubing runs from
the pump to the fuel tank in your aircraft. For
those who use a 1-gallon fuel can instead of a
bottle, Du-Bro offers an alternate Fillin’
Station (catalog number 909).
The hand-crank fuel pump will force fuel
from the bottle to the tank when cranked in
one direction. Turning it the opposite
direction will withdraw fuel from the tank at
the end of your flying session. It pumps only
when you are cranking the handle. A
receptacle is included for the fuel spout so it
doesn’t touch the ground and attract dirt.
The Glo-Plug Ignitor is self-contained
with its own battery. It is attached directly to
the glow plug without the need for a cable.
The only thing missing on this equipment
caddy is a starter motor.
In an attempt to eliminate all those cables,
I like to use a self-contained starter with its
own integral battery pack. This makes the
starter completely portable without the need
for any cable.
I use the Sullivan Deluxe Hi-Tork Starter
(www.sullivanproducts.com/) along with its
PowerPac Battery Case and charger. This
case holds 12 SCR 1400 mAh, Sub-C Ni-Cd
battery cells.
I also noticed that Hobby Lobby
International has the Kavan Planetary Gear
Starter along with a Ni-Cd battery holder (at
www.hobby-lobby.com/kavan.htm). These
self-contained starters cost more, but having
complete portability, without the need for
cables, is a plus on the flightline. I hope all
this will prove to be helpful.
Q252: “I noted that a new series of microsize
brushless motors is now available under the
name Mighty Midget. Didn’t I hear that same
name used years ago?”
A252: This was bounced around on all the
electric Internet forums recently. Yes, one of
our old actuators for galloping ghost RC
systems involved the use of a geared electric
motor called the “Mighty Midget.”
Since everyone was discussing this name,
I thought it would be appropriate to show a
photo of the old motor from the 1950s. MA
Associate Editor Michael Ramsey was kind
enough to locate a Mighty Midget in the
AMA museum and took the photo presented
here.
In contrast, the new Mighty Midget Gold
Series motors have just been introduced in the
US and are available from Bob Selman
Designs (www.bsdmicrorc.com/products.
cfm?catID=10037). These motors are made
by N. Chandrashekwar and his son Uttam of
Bangalore, India.
The outrunner shown in the photo weighs
only 7 grams (0.25 ounce) with propeller,
propeller adapter, mount, and connector. It
runs on two Li-Poly cells at roughly 1.5 amps
motor current and approximately 10-12 watts
of power input. This would make it suitable
to fly models weighing 3-6 ounces.
I expect to use this motor in a new 4-
ounce design, employing a Castle Creations
Phoenix-10 ESC, an FMA Direct M5V2
receiver, and two Hitec HS-50 servos. With
suitable micro substitutes it will be easy to get
model weights down to less than 3 ounces
while still using proportional-feedback servos
(not magnetic actuators).
Q253: “We have been told time and time
again not to discharge Li-Poly battery cells
below approximately 3.0 volts. To make sure
this isn’t a problem, our modern ESCs now
have built-in cutoff circuits that limit the total
voltage to not less than 3.0 volts per cell.
“But I did a little digging and discovered
that not all ESCs work the same way. How
about explaining this subject further?”
A253: Many of the modern ESCs (most of
which are now of the brushless variety) will
either let you program the exact voltage
cutoff or use cell-count detection to set the
cutoff to 3.0 volts per cell when using Li-Poly
batteries.
However, not every ESC works in this
manner. Some use a scheme in which the
total voltage is measured at the time the
power is turned on, and then a level, such as
70% of that total, is picked for the cutoff.
Here is where the problem arises. Let’s
say you have a battery capacity that can run
your motor for 30 minutes. But that’s a really
long flight time, so you decided on a singlecharge to make three separate flights adding
up to 30 minutes.
Each successive time you start the motor
the total voltage is going to be lower, and then
70% of that lower number will allow the
battery to go lower and lower than the desired
3.0 volts per cell. That type of concept is the
wrong way to go when using Li-Poly batteries.
I’m not going to embarrass any
manufacturers at this time, but I do advise you
to inquire about the cutoff setting method when
purchasing any ESC. If your question cannot
be answered, you don’t want that product.
I checked with Shawn Palmer at Castle
Creations and learned that not only can its
ESCs be programmed for cutoff, but even the
company’s less expensive Thunderbird line
employs actual cell-count detection.
But to give you a really warm feeling, each
time you turn your power on, the Castle
Creations ESCs follow a sequence and beep
the number of cells in the pack to confirm the
actual voltage cutoff for that particular flight. I
like that feature a lot!
Q254: “I keep hearing the pros and cons about
cycling (charging and discharging) new Li-
Poly batteries initially at moderate rates as a
form of break-in. Is this really necessary?”
A254: You might say the jury is still out on
this, but that is to be expected with Li-Poly
batteries because it is still a new technology
and we are still learning. I asked several
vendors, and they indicated that breaking in
new Li-Poly battery packs was essential!
I got an opposite viewpoint from an honest
and respected friend: FMA Direct President
Fred Marks. I don’t think Fred would mind my
paraphrasing his recent E-mail response to me
on this subject.
“I’ve written many times: if you take the
time and trouble to do a so-called ‘break-in’ on
your new Li-Poly battery packs, it may only
increase your packs’ capacity by a fraction of a
percent up to about 10 cycles. It’s just not
worth fiddling with. Proper balanced cell
charging will accomplish far more advantages
in both service life and sustained capacity than
any break-in period might produce.”
For now I’ll take Fred’s advice and just
keep on flying! MA
Edition: Model Aviation - 2006/10
Page Numbers: 79,80,82,84
Edition: Model Aviation - 2006/10
Page Numbers: 79,80,82,84
THIS IS MY 31st
monthly column in
which I try to give
you the best possible
answers to questions
you have written or
E-mailed to me.
Each new question is
given a sequential number for identification purposes.
Until the August 2005 column this material had appeared in
the pages of MA, and additional questions and answers had been
posted on a special section of the AMA Web site (www.modelair
craft.org). That Web page is now in the process of being revised and,
as such, there will be no new postings in the foreseeable future.
What you read each month in print is all you will see. I will advise
you when we are able to return to the original format. The original
“search process” by categories will also be suspended until the posting
is back online.
In the meantime, I’m available to help you locate specific subjects
of interest. Just drop me an E-mail. Also please keep sending in your
questions; that’s the only way I can continue to provide this service to
readers.
Q251: “I’m very new to the hobby and I’m not sure what kind of field
support equipment I need to be able to fuel and start my glow engine.”
A251: Before answering this question I looked at several catalogs
from the major mail-order suppliers to see what type of field support
equipment is available for the modeler. It is amazing that such a
What are the basic field support equipment needs for the newcomer?
October 2006 79
? Frequently Asked Questions Bob Aberle | [email protected]
Also included in this column:
• Return of the Mighty Midget?
• ESCs and Li-Poly batteries
• Is Li-Poly break-in really
necessary?
Components of the Du-Bro Fillin’ Station flightline fuel caddy. Everything is basically
attached to the top of a 1-gallon fuel bottle.
A separate charger is supplied to charge single Ni-Cd cell inside
Glo-Plug Ignitor. This takes overnight to fully charge.
Fillin’ Station mounted to top of fuel
bottle. Separate caddy is supplied to hold
Glo-Plug Ignitor (in Bob’s hand).
10sig3.QXD 8/24/06 10:18 AM Page 79variety of equipment exists. It must be bewildering to the hobby
newcomer.
I’m sure your local hobby shop will gladly set you up with all the
right items. I will tell you what I use and why I use it, but recognize
that there are many different answers to this reader’s question.
The basic needs for fueling and starting a glow engine involve
filling the fuel tank, lighting (or powering) the glow plug located at the
top of the engine’s cylinder head, and flipping or turning the propeller
over until the engine fires (starts).
Some modelers favor a field kit with a power panel that provides
power distribution from a single 12-volt battery to an electric fuel
pump, to a glow-plug lighter, and to a starter motor to turn over the
propeller. This is a good concept because you need only one 12-volt
gelled cell battery to power everything. Thus only one battery has to
be charged before venturing out to the flying field.
Using an electric fuel pump is fast and easy. However, if you don’t
stop the pump in time (or leave it running and walk away), you can
80 MODEL AVIATION
Popular Castle Creations brushless ESCs. Phoenix-10 can be
programmed with aid of PC. Thunderbird-18 will detect cell count
and set low-voltage cutoff accordingly.
The modern Mighty Midget Gold Series outrunner motor weighs
less than 7 grams and can fly a 3- to 6-ounce model.
Ignitor clips directly to glow plug located
on top of engine. Shown is rare Cooney .61
designed and built by Fourmost Racing
Products’ Ralph Cooney. It never went
into production. Mighty Midget motor/actuator as used in the 1950s. MA Associate Editor Michael Ramsey
found it in the AMA National Model Aviation Museum and took this photo.
easily overflow fuel onto the ground. Environmentalists don’t like
seeing fuel spilled on the ground since it can affect the ground water.
In addition to that problem, you will need separate cables running
up to the glow plug and to your starter motor. That results in a lot of
wire hanging off your field kit.
My approach to field equipment is different; I chose the Du-Bro
catalog number 907 Fillin’ Station flightline fuel caddy (http://dub
ro.com/hobby/). It is made from a molded plastic that is not
affected by glow fuel or gasoline.
The main bracket basically mounts on top of your 1-gallon fuel
bottle, in place of the normal cap. To this bracket a manual (hand
crank) fuel pump is attached. There are provisions for several tools,
and a four-way socket wrench is included. This wrench will remove
glow plugs and tighten prop nuts. There is also room for two extra
glow plugs since they burn out quite often.
A Du-Bro Kwik Start Glo-Plug Ignitor is provided, along with a
10sig3.QXD 8/24/06 10:21 AM Page 80suitable charger. There is a caddy on the
bracket on which to stow the ignitor when it’s
not in use.
Fuel tubing is also supplied. One length
goes inside the cap and runs to the bottom of
the fuel bottle. A filter is placed on the end of
that line. Another length of tubing runs from
the pump to the fuel tank in your aircraft. For
those who use a 1-gallon fuel can instead of a
bottle, Du-Bro offers an alternate Fillin’
Station (catalog number 909).
The hand-crank fuel pump will force fuel
from the bottle to the tank when cranked in
one direction. Turning it the opposite
direction will withdraw fuel from the tank at
the end of your flying session. It pumps only
when you are cranking the handle. A
receptacle is included for the fuel spout so it
doesn’t touch the ground and attract dirt.
The Glo-Plug Ignitor is self-contained
with its own battery. It is attached directly to
the glow plug without the need for a cable.
The only thing missing on this equipment
caddy is a starter motor.
In an attempt to eliminate all those cables,
I like to use a self-contained starter with its
own integral battery pack. This makes the
starter completely portable without the need
for any cable.
I use the Sullivan Deluxe Hi-Tork Starter
(www.sullivanproducts.com/) along with its
PowerPac Battery Case and charger. This
case holds 12 SCR 1400 mAh, Sub-C Ni-Cd
battery cells.
I also noticed that Hobby Lobby
International has the Kavan Planetary Gear
Starter along with a Ni-Cd battery holder (at
www.hobby-lobby.com/kavan.htm). These
self-contained starters cost more, but having
complete portability, without the need for
cables, is a plus on the flightline. I hope all
this will prove to be helpful.
Q252: “I noted that a new series of microsize
brushless motors is now available under the
name Mighty Midget. Didn’t I hear that same
name used years ago?”
A252: This was bounced around on all the
electric Internet forums recently. Yes, one of
our old actuators for galloping ghost RC
systems involved the use of a geared electric
motor called the “Mighty Midget.”
Since everyone was discussing this name,
I thought it would be appropriate to show a
photo of the old motor from the 1950s. MA
Associate Editor Michael Ramsey was kind
enough to locate a Mighty Midget in the
AMA museum and took the photo presented
here.
In contrast, the new Mighty Midget Gold
Series motors have just been introduced in the
US and are available from Bob Selman
Designs (www.bsdmicrorc.com/products.
cfm?catID=10037). These motors are made
by N. Chandrashekwar and his son Uttam of
Bangalore, India.
The outrunner shown in the photo weighs
only 7 grams (0.25 ounce) with propeller,
propeller adapter, mount, and connector. It
runs on two Li-Poly cells at roughly 1.5 amps
motor current and approximately 10-12 watts
of power input. This would make it suitable
to fly models weighing 3-6 ounces.
I expect to use this motor in a new 4-
ounce design, employing a Castle Creations
Phoenix-10 ESC, an FMA Direct M5V2
receiver, and two Hitec HS-50 servos. With
suitable micro substitutes it will be easy to get
model weights down to less than 3 ounces
while still using proportional-feedback servos
(not magnetic actuators).
Q253: “We have been told time and time
again not to discharge Li-Poly battery cells
below approximately 3.0 volts. To make sure
this isn’t a problem, our modern ESCs now
have built-in cutoff circuits that limit the total
voltage to not less than 3.0 volts per cell.
“But I did a little digging and discovered
that not all ESCs work the same way. How
about explaining this subject further?”
A253: Many of the modern ESCs (most of
which are now of the brushless variety) will
either let you program the exact voltage
cutoff or use cell-count detection to set the
cutoff to 3.0 volts per cell when using Li-Poly
batteries.
However, not every ESC works in this
manner. Some use a scheme in which the
total voltage is measured at the time the
power is turned on, and then a level, such as
70% of that total, is picked for the cutoff.
Here is where the problem arises. Let’s
say you have a battery capacity that can run
your motor for 30 minutes. But that’s a really
long flight time, so you decided on a singlecharge to make three separate flights adding
up to 30 minutes.
Each successive time you start the motor
the total voltage is going to be lower, and then
70% of that lower number will allow the
battery to go lower and lower than the desired
3.0 volts per cell. That type of concept is the
wrong way to go when using Li-Poly batteries.
I’m not going to embarrass any
manufacturers at this time, but I do advise you
to inquire about the cutoff setting method when
purchasing any ESC. If your question cannot
be answered, you don’t want that product.
I checked with Shawn Palmer at Castle
Creations and learned that not only can its
ESCs be programmed for cutoff, but even the
company’s less expensive Thunderbird line
employs actual cell-count detection.
But to give you a really warm feeling, each
time you turn your power on, the Castle
Creations ESCs follow a sequence and beep
the number of cells in the pack to confirm the
actual voltage cutoff for that particular flight. I
like that feature a lot!
Q254: “I keep hearing the pros and cons about
cycling (charging and discharging) new Li-
Poly batteries initially at moderate rates as a
form of break-in. Is this really necessary?”
A254: You might say the jury is still out on
this, but that is to be expected with Li-Poly
batteries because it is still a new technology
and we are still learning. I asked several
vendors, and they indicated that breaking in
new Li-Poly battery packs was essential!
I got an opposite viewpoint from an honest
and respected friend: FMA Direct President
Fred Marks. I don’t think Fred would mind my
paraphrasing his recent E-mail response to me
on this subject.
“I’ve written many times: if you take the
time and trouble to do a so-called ‘break-in’ on
your new Li-Poly battery packs, it may only
increase your packs’ capacity by a fraction of a
percent up to about 10 cycles. It’s just not
worth fiddling with. Proper balanced cell
charging will accomplish far more advantages
in both service life and sustained capacity than
any break-in period might produce.”
For now I’ll take Fred’s advice and just
keep on flying! MA
Edition: Model Aviation - 2006/10
Page Numbers: 79,80,82,84
THIS IS MY 31st
monthly column in
which I try to give
you the best possible
answers to questions
you have written or
E-mailed to me.
Each new question is
given a sequential number for identification purposes.
Until the August 2005 column this material had appeared in
the pages of MA, and additional questions and answers had been
posted on a special section of the AMA Web site (www.modelair
craft.org). That Web page is now in the process of being revised and,
as such, there will be no new postings in the foreseeable future.
What you read each month in print is all you will see. I will advise
you when we are able to return to the original format. The original
“search process” by categories will also be suspended until the posting
is back online.
In the meantime, I’m available to help you locate specific subjects
of interest. Just drop me an E-mail. Also please keep sending in your
questions; that’s the only way I can continue to provide this service to
readers.
Q251: “I’m very new to the hobby and I’m not sure what kind of field
support equipment I need to be able to fuel and start my glow engine.”
A251: Before answering this question I looked at several catalogs
from the major mail-order suppliers to see what type of field support
equipment is available for the modeler. It is amazing that such a
What are the basic field support equipment needs for the newcomer?
October 2006 79
? Frequently Asked Questions Bob Aberle | [email protected]
Also included in this column:
• Return of the Mighty Midget?
• ESCs and Li-Poly batteries
• Is Li-Poly break-in really
necessary?
Components of the Du-Bro Fillin’ Station flightline fuel caddy. Everything is basically
attached to the top of a 1-gallon fuel bottle.
A separate charger is supplied to charge single Ni-Cd cell inside
Glo-Plug Ignitor. This takes overnight to fully charge.
Fillin’ Station mounted to top of fuel
bottle. Separate caddy is supplied to hold
Glo-Plug Ignitor (in Bob’s hand).
10sig3.QXD 8/24/06 10:18 AM Page 79variety of equipment exists. It must be bewildering to the hobby
newcomer.
I’m sure your local hobby shop will gladly set you up with all the
right items. I will tell you what I use and why I use it, but recognize
that there are many different answers to this reader’s question.
The basic needs for fueling and starting a glow engine involve
filling the fuel tank, lighting (or powering) the glow plug located at the
top of the engine’s cylinder head, and flipping or turning the propeller
over until the engine fires (starts).
Some modelers favor a field kit with a power panel that provides
power distribution from a single 12-volt battery to an electric fuel
pump, to a glow-plug lighter, and to a starter motor to turn over the
propeller. This is a good concept because you need only one 12-volt
gelled cell battery to power everything. Thus only one battery has to
be charged before venturing out to the flying field.
Using an electric fuel pump is fast and easy. However, if you don’t
stop the pump in time (or leave it running and walk away), you can
80 MODEL AVIATION
Popular Castle Creations brushless ESCs. Phoenix-10 can be
programmed with aid of PC. Thunderbird-18 will detect cell count
and set low-voltage cutoff accordingly.
The modern Mighty Midget Gold Series outrunner motor weighs
less than 7 grams and can fly a 3- to 6-ounce model.
Ignitor clips directly to glow plug located
on top of engine. Shown is rare Cooney .61
designed and built by Fourmost Racing
Products’ Ralph Cooney. It never went
into production. Mighty Midget motor/actuator as used in the 1950s. MA Associate Editor Michael Ramsey
found it in the AMA National Model Aviation Museum and took this photo.
easily overflow fuel onto the ground. Environmentalists don’t like
seeing fuel spilled on the ground since it can affect the ground water.
In addition to that problem, you will need separate cables running
up to the glow plug and to your starter motor. That results in a lot of
wire hanging off your field kit.
My approach to field equipment is different; I chose the Du-Bro
catalog number 907 Fillin’ Station flightline fuel caddy (http://dub
ro.com/hobby/). It is made from a molded plastic that is not
affected by glow fuel or gasoline.
The main bracket basically mounts on top of your 1-gallon fuel
bottle, in place of the normal cap. To this bracket a manual (hand
crank) fuel pump is attached. There are provisions for several tools,
and a four-way socket wrench is included. This wrench will remove
glow plugs and tighten prop nuts. There is also room for two extra
glow plugs since they burn out quite often.
A Du-Bro Kwik Start Glo-Plug Ignitor is provided, along with a
10sig3.QXD 8/24/06 10:21 AM Page 80suitable charger. There is a caddy on the
bracket on which to stow the ignitor when it’s
not in use.
Fuel tubing is also supplied. One length
goes inside the cap and runs to the bottom of
the fuel bottle. A filter is placed on the end of
that line. Another length of tubing runs from
the pump to the fuel tank in your aircraft. For
those who use a 1-gallon fuel can instead of a
bottle, Du-Bro offers an alternate Fillin’
Station (catalog number 909).
The hand-crank fuel pump will force fuel
from the bottle to the tank when cranked in
one direction. Turning it the opposite
direction will withdraw fuel from the tank at
the end of your flying session. It pumps only
when you are cranking the handle. A
receptacle is included for the fuel spout so it
doesn’t touch the ground and attract dirt.
The Glo-Plug Ignitor is self-contained
with its own battery. It is attached directly to
the glow plug without the need for a cable.
The only thing missing on this equipment
caddy is a starter motor.
In an attempt to eliminate all those cables,
I like to use a self-contained starter with its
own integral battery pack. This makes the
starter completely portable without the need
for any cable.
I use the Sullivan Deluxe Hi-Tork Starter
(www.sullivanproducts.com/) along with its
PowerPac Battery Case and charger. This
case holds 12 SCR 1400 mAh, Sub-C Ni-Cd
battery cells.
I also noticed that Hobby Lobby
International has the Kavan Planetary Gear
Starter along with a Ni-Cd battery holder (at
www.hobby-lobby.com/kavan.htm). These
self-contained starters cost more, but having
complete portability, without the need for
cables, is a plus on the flightline. I hope all
this will prove to be helpful.
Q252: “I noted that a new series of microsize
brushless motors is now available under the
name Mighty Midget. Didn’t I hear that same
name used years ago?”
A252: This was bounced around on all the
electric Internet forums recently. Yes, one of
our old actuators for galloping ghost RC
systems involved the use of a geared electric
motor called the “Mighty Midget.”
Since everyone was discussing this name,
I thought it would be appropriate to show a
photo of the old motor from the 1950s. MA
Associate Editor Michael Ramsey was kind
enough to locate a Mighty Midget in the
AMA museum and took the photo presented
here.
In contrast, the new Mighty Midget Gold
Series motors have just been introduced in the
US and are available from Bob Selman
Designs (www.bsdmicrorc.com/products.
cfm?catID=10037). These motors are made
by N. Chandrashekwar and his son Uttam of
Bangalore, India.
The outrunner shown in the photo weighs
only 7 grams (0.25 ounce) with propeller,
propeller adapter, mount, and connector. It
runs on two Li-Poly cells at roughly 1.5 amps
motor current and approximately 10-12 watts
of power input. This would make it suitable
to fly models weighing 3-6 ounces.
I expect to use this motor in a new 4-
ounce design, employing a Castle Creations
Phoenix-10 ESC, an FMA Direct M5V2
receiver, and two Hitec HS-50 servos. With
suitable micro substitutes it will be easy to get
model weights down to less than 3 ounces
while still using proportional-feedback servos
(not magnetic actuators).
Q253: “We have been told time and time
again not to discharge Li-Poly battery cells
below approximately 3.0 volts. To make sure
this isn’t a problem, our modern ESCs now
have built-in cutoff circuits that limit the total
voltage to not less than 3.0 volts per cell.
“But I did a little digging and discovered
that not all ESCs work the same way. How
about explaining this subject further?”
A253: Many of the modern ESCs (most of
which are now of the brushless variety) will
either let you program the exact voltage
cutoff or use cell-count detection to set the
cutoff to 3.0 volts per cell when using Li-Poly
batteries.
However, not every ESC works in this
manner. Some use a scheme in which the
total voltage is measured at the time the
power is turned on, and then a level, such as
70% of that total, is picked for the cutoff.
Here is where the problem arises. Let’s
say you have a battery capacity that can run
your motor for 30 minutes. But that’s a really
long flight time, so you decided on a singlecharge to make three separate flights adding
up to 30 minutes.
Each successive time you start the motor
the total voltage is going to be lower, and then
70% of that lower number will allow the
battery to go lower and lower than the desired
3.0 volts per cell. That type of concept is the
wrong way to go when using Li-Poly batteries.
I’m not going to embarrass any
manufacturers at this time, but I do advise you
to inquire about the cutoff setting method when
purchasing any ESC. If your question cannot
be answered, you don’t want that product.
I checked with Shawn Palmer at Castle
Creations and learned that not only can its
ESCs be programmed for cutoff, but even the
company’s less expensive Thunderbird line
employs actual cell-count detection.
But to give you a really warm feeling, each
time you turn your power on, the Castle
Creations ESCs follow a sequence and beep
the number of cells in the pack to confirm the
actual voltage cutoff for that particular flight. I
like that feature a lot!
Q254: “I keep hearing the pros and cons about
cycling (charging and discharging) new Li-
Poly batteries initially at moderate rates as a
form of break-in. Is this really necessary?”
A254: You might say the jury is still out on
this, but that is to be expected with Li-Poly
batteries because it is still a new technology
and we are still learning. I asked several
vendors, and they indicated that breaking in
new Li-Poly battery packs was essential!
I got an opposite viewpoint from an honest
and respected friend: FMA Direct President
Fred Marks. I don’t think Fred would mind my
paraphrasing his recent E-mail response to me
on this subject.
“I’ve written many times: if you take the
time and trouble to do a so-called ‘break-in’ on
your new Li-Poly battery packs, it may only
increase your packs’ capacity by a fraction of a
percent up to about 10 cycles. It’s just not
worth fiddling with. Proper balanced cell
charging will accomplish far more advantages
in both service life and sustained capacity than
any break-in period might produce.”
For now I’ll take Fred’s advice and just
keep on flying! MA
Edition: Model Aviation - 2006/10
Page Numbers: 79,80,82,84
THIS IS MY 31st
monthly column in
which I try to give
you the best possible
answers to questions
you have written or
E-mailed to me.
Each new question is
given a sequential number for identification purposes.
Until the August 2005 column this material had appeared in
the pages of MA, and additional questions and answers had been
posted on a special section of the AMA Web site (www.modelair
craft.org). That Web page is now in the process of being revised and,
as such, there will be no new postings in the foreseeable future.
What you read each month in print is all you will see. I will advise
you when we are able to return to the original format. The original
“search process” by categories will also be suspended until the posting
is back online.
In the meantime, I’m available to help you locate specific subjects
of interest. Just drop me an E-mail. Also please keep sending in your
questions; that’s the only way I can continue to provide this service to
readers.
Q251: “I’m very new to the hobby and I’m not sure what kind of field
support equipment I need to be able to fuel and start my glow engine.”
A251: Before answering this question I looked at several catalogs
from the major mail-order suppliers to see what type of field support
equipment is available for the modeler. It is amazing that such a
What are the basic field support equipment needs for the newcomer?
October 2006 79
? Frequently Asked Questions Bob Aberle | [email protected]
Also included in this column:
• Return of the Mighty Midget?
• ESCs and Li-Poly batteries
• Is Li-Poly break-in really
necessary?
Components of the Du-Bro Fillin’ Station flightline fuel caddy. Everything is basically
attached to the top of a 1-gallon fuel bottle.
A separate charger is supplied to charge single Ni-Cd cell inside
Glo-Plug Ignitor. This takes overnight to fully charge.
Fillin’ Station mounted to top of fuel
bottle. Separate caddy is supplied to hold
Glo-Plug Ignitor (in Bob’s hand).
10sig3.QXD 8/24/06 10:18 AM Page 79variety of equipment exists. It must be bewildering to the hobby
newcomer.
I’m sure your local hobby shop will gladly set you up with all the
right items. I will tell you what I use and why I use it, but recognize
that there are many different answers to this reader’s question.
The basic needs for fueling and starting a glow engine involve
filling the fuel tank, lighting (or powering) the glow plug located at the
top of the engine’s cylinder head, and flipping or turning the propeller
over until the engine fires (starts).
Some modelers favor a field kit with a power panel that provides
power distribution from a single 12-volt battery to an electric fuel
pump, to a glow-plug lighter, and to a starter motor to turn over the
propeller. This is a good concept because you need only one 12-volt
gelled cell battery to power everything. Thus only one battery has to
be charged before venturing out to the flying field.
Using an electric fuel pump is fast and easy. However, if you don’t
stop the pump in time (or leave it running and walk away), you can
80 MODEL AVIATION
Popular Castle Creations brushless ESCs. Phoenix-10 can be
programmed with aid of PC. Thunderbird-18 will detect cell count
and set low-voltage cutoff accordingly.
The modern Mighty Midget Gold Series outrunner motor weighs
less than 7 grams and can fly a 3- to 6-ounce model.
Ignitor clips directly to glow plug located
on top of engine. Shown is rare Cooney .61
designed and built by Fourmost Racing
Products’ Ralph Cooney. It never went
into production. Mighty Midget motor/actuator as used in the 1950s. MA Associate Editor Michael Ramsey
found it in the AMA National Model Aviation Museum and took this photo.
easily overflow fuel onto the ground. Environmentalists don’t like
seeing fuel spilled on the ground since it can affect the ground water.
In addition to that problem, you will need separate cables running
up to the glow plug and to your starter motor. That results in a lot of
wire hanging off your field kit.
My approach to field equipment is different; I chose the Du-Bro
catalog number 907 Fillin’ Station flightline fuel caddy (http://dub
ro.com/hobby/). It is made from a molded plastic that is not
affected by glow fuel or gasoline.
The main bracket basically mounts on top of your 1-gallon fuel
bottle, in place of the normal cap. To this bracket a manual (hand
crank) fuel pump is attached. There are provisions for several tools,
and a four-way socket wrench is included. This wrench will remove
glow plugs and tighten prop nuts. There is also room for two extra
glow plugs since they burn out quite often.
A Du-Bro Kwik Start Glo-Plug Ignitor is provided, along with a
10sig3.QXD 8/24/06 10:21 AM Page 80suitable charger. There is a caddy on the
bracket on which to stow the ignitor when it’s
not in use.
Fuel tubing is also supplied. One length
goes inside the cap and runs to the bottom of
the fuel bottle. A filter is placed on the end of
that line. Another length of tubing runs from
the pump to the fuel tank in your aircraft. For
those who use a 1-gallon fuel can instead of a
bottle, Du-Bro offers an alternate Fillin’
Station (catalog number 909).
The hand-crank fuel pump will force fuel
from the bottle to the tank when cranked in
one direction. Turning it the opposite
direction will withdraw fuel from the tank at
the end of your flying session. It pumps only
when you are cranking the handle. A
receptacle is included for the fuel spout so it
doesn’t touch the ground and attract dirt.
The Glo-Plug Ignitor is self-contained
with its own battery. It is attached directly to
the glow plug without the need for a cable.
The only thing missing on this equipment
caddy is a starter motor.
In an attempt to eliminate all those cables,
I like to use a self-contained starter with its
own integral battery pack. This makes the
starter completely portable without the need
for any cable.
I use the Sullivan Deluxe Hi-Tork Starter
(www.sullivanproducts.com/) along with its
PowerPac Battery Case and charger. This
case holds 12 SCR 1400 mAh, Sub-C Ni-Cd
battery cells.
I also noticed that Hobby Lobby
International has the Kavan Planetary Gear
Starter along with a Ni-Cd battery holder (at
www.hobby-lobby.com/kavan.htm). These
self-contained starters cost more, but having
complete portability, without the need for
cables, is a plus on the flightline. I hope all
this will prove to be helpful.
Q252: “I noted that a new series of microsize
brushless motors is now available under the
name Mighty Midget. Didn’t I hear that same
name used years ago?”
A252: This was bounced around on all the
electric Internet forums recently. Yes, one of
our old actuators for galloping ghost RC
systems involved the use of a geared electric
motor called the “Mighty Midget.”
Since everyone was discussing this name,
I thought it would be appropriate to show a
photo of the old motor from the 1950s. MA
Associate Editor Michael Ramsey was kind
enough to locate a Mighty Midget in the
AMA museum and took the photo presented
here.
In contrast, the new Mighty Midget Gold
Series motors have just been introduced in the
US and are available from Bob Selman
Designs (www.bsdmicrorc.com/products.
cfm?catID=10037). These motors are made
by N. Chandrashekwar and his son Uttam of
Bangalore, India.
The outrunner shown in the photo weighs
only 7 grams (0.25 ounce) with propeller,
propeller adapter, mount, and connector. It
runs on two Li-Poly cells at roughly 1.5 amps
motor current and approximately 10-12 watts
of power input. This would make it suitable
to fly models weighing 3-6 ounces.
I expect to use this motor in a new 4-
ounce design, employing a Castle Creations
Phoenix-10 ESC, an FMA Direct M5V2
receiver, and two Hitec HS-50 servos. With
suitable micro substitutes it will be easy to get
model weights down to less than 3 ounces
while still using proportional-feedback servos
(not magnetic actuators).
Q253: “We have been told time and time
again not to discharge Li-Poly battery cells
below approximately 3.0 volts. To make sure
this isn’t a problem, our modern ESCs now
have built-in cutoff circuits that limit the total
voltage to not less than 3.0 volts per cell.
“But I did a little digging and discovered
that not all ESCs work the same way. How
about explaining this subject further?”
A253: Many of the modern ESCs (most of
which are now of the brushless variety) will
either let you program the exact voltage
cutoff or use cell-count detection to set the
cutoff to 3.0 volts per cell when using Li-Poly
batteries.
However, not every ESC works in this
manner. Some use a scheme in which the
total voltage is measured at the time the
power is turned on, and then a level, such as
70% of that total, is picked for the cutoff.
Here is where the problem arises. Let’s
say you have a battery capacity that can run
your motor for 30 minutes. But that’s a really
long flight time, so you decided on a singlecharge to make three separate flights adding
up to 30 minutes.
Each successive time you start the motor
the total voltage is going to be lower, and then
70% of that lower number will allow the
battery to go lower and lower than the desired
3.0 volts per cell. That type of concept is the
wrong way to go when using Li-Poly batteries.
I’m not going to embarrass any
manufacturers at this time, but I do advise you
to inquire about the cutoff setting method when
purchasing any ESC. If your question cannot
be answered, you don’t want that product.
I checked with Shawn Palmer at Castle
Creations and learned that not only can its
ESCs be programmed for cutoff, but even the
company’s less expensive Thunderbird line
employs actual cell-count detection.
But to give you a really warm feeling, each
time you turn your power on, the Castle
Creations ESCs follow a sequence and beep
the number of cells in the pack to confirm the
actual voltage cutoff for that particular flight. I
like that feature a lot!
Q254: “I keep hearing the pros and cons about
cycling (charging and discharging) new Li-
Poly batteries initially at moderate rates as a
form of break-in. Is this really necessary?”
A254: You might say the jury is still out on
this, but that is to be expected with Li-Poly
batteries because it is still a new technology
and we are still learning. I asked several
vendors, and they indicated that breaking in
new Li-Poly battery packs was essential!
I got an opposite viewpoint from an honest
and respected friend: FMA Direct President
Fred Marks. I don’t think Fred would mind my
paraphrasing his recent E-mail response to me
on this subject.
“I’ve written many times: if you take the
time and trouble to do a so-called ‘break-in’ on
your new Li-Poly battery packs, it may only
increase your packs’ capacity by a fraction of a
percent up to about 10 cycles. It’s just not
worth fiddling with. Proper balanced cell
charging will accomplish far more advantages
in both service life and sustained capacity than
any break-in period might produce.”
For now I’ll take Fred’s advice and just
keep on flying! MA