December 2011 129
GLIDERS wERE
around before
powered flight and
are still used as a
learning tool in
designing powered
aircraft. The
Society of Antique
Modelers (SAM)
organization has competition classes for four glider categories.
Yes, I know, modern glider pilots prefer that they be called
sailplanes, but let’s relax about nomenclature, especially when the
term glider came first.
Three of the glider events are FF and are held at the annual
SAM Champs. They are Hand-Launched Glider, Towline, and
Catapult-Launched Glider. Hand-Launched should be selfexplanatory,
but as I write this, there’s an unsettled rules
discussion about whether wingtip launches will be permanently
permitted. The tip-launch technique tests the fliers’ agility to a
Four Glider events
Old-Timers Bob Angel | [email protected]
Photographer Ned Nevels did some Photoshop work on this photo of Don Bishop’s bomber
takeoff at the flying site in Taft CA. The next OT event there will be in March 2012.
This graceful-looking Albatross glider
was first kitted by Cleveland Models in
1944. Red Scholefield submitted the
photo.
Eric Strengel launches his FF
Playboy at the 2011 Southwest
Regionals held each January in
Eloy AZ. The cars are farther
away than they appear
because of photographer Mike
Woodhouse’s telephoto lens.
Also included in this column:
• Some glow plug history
• Arden engines
higher degree, elevating the competition level over more
conventional launch techniques.
The Catapult event is more docile for many in SAM’s
average age group. The catapult is a simple 6-inch-long dowel
with a 9-inch (unstretched) loop of flat rubber band attached.
One hand holds the dowel and the other holds and releases the
glider. This event obviously favors the flier with the longest
arms, but proxy launches by pet orangutans are specifically
prohibited.
The FF Towline event allows either a 200-foot handheld
towline or a 25-foot hi-start with 150 feet of line attached.
Modern circle tow devices aren’t allowed, but auto rudder is
okay. Glider designs for the FF events must predate 1943.
The RC event is called Old-Timer (OT) Glider, and the rules
allow launch by either hi-start or winch. However, in practice the
pilots usually observe an unwritten agreement to stick to histarts.
Modern “hot” winches, which would elevate the
competition level, require more support equipment and employ
beefier aircraft structures. That would probably result in the
eventual demise of the event.
For each of the four events described, there’s more fine print
in the rule book. As with any competition, you should get the
rules straight before setting out to build a model. Do you
suppose I chose this glider subject just as an excuse to show that
fine-looking Cleveland Albatross photo? The model was kitted
in 1944, so it’s only eligible for the RC event that allows designs
up through 1946.
Ray Arden is generally credited with inventing the glow plug.
But, as with many inventions, there were other contributors—
some were competitors, and some took part as collaborators. In
Ray’s case, he collaborated with Ben Shereshaw, designer of the
Bantam engines, and also Ed Chamberlin. These men probably
took clues from full-scale engine experimenters who used
various “hot plugs” for ignition.
In the early 1900s, model engines provided low power and
were heavy—their weight was measured in pounds, not ounces.
Ray Arden was obsessed with designing smaller, lighter engines
and support equipment. As a teenager, he built his first engine in
his home shop. His ignition system was a vibrating-coil type that
provided a continuous series of sparks. These untimed random
sparks didn’t provide optimum power. At one point, he added an
early glow plug, used along with the continuous spark, to
achieve smoother running.
I once had an accidental acquaintance with vibrating
continuous spark while breaking in an Ohlsson & Rice 23 on a
test stand. The alligator clip on the coil’s point lead popped loose
with the engine running. The clip came to rest, lightly touching
the timer case. It vibrated against the grounded case, producing a
steady stream of sparks. To my surprise the engine continued to
run, slowing very little, until I switched off the battery power.
Before modelers had ever heard of glow plugs, I remember a
new hot fuel that was being marketed as “Liquid Dynamite.”
Through experimentation—and maybe some accidental luck—
Ed, Ben, and Ray found that with this hot fuel you could get an
engine running strongly, then disconnect the spark ignition
system and have the engine continue running. The spark plug’s
side electrode became hot enough to act as a glow plug.
Today, hot plugs occasionally cause problems for OT fliers
when using FAI fuel in spark-ignition engines. The engines don’t
always quit running when the ignition is shut off. Colder spark
plugs usually cure this.
Ray Arden had succeeded in designing and marketing his
small, lightweight engines, starting with the Atom .09 and later
the Arden .09 and Arden 19. He developed lightweight coils and
finally a small FF chassis that integrated the complete ignition
system in a slender plastic package. But those experiments with
Liquid Dynamite had sparked the idea of eliminating the heavy
coil, condenser, batteries, and wiring.
Ray and Ben Shereshaw contributed to developing the final
coiled-wire glow plug. Then a plating of platinum/iridium was
added to the wire to provide more heat through catalytic action.
I recall a vivid demonstration of this
catalytic action in the form of a novel
cigarette lighter that resembled a lipstick
tube. The tube was lined with methanolsaturated
cotton and a platinum-plated
wire was stretched across the top of the
plastic fuel tanks were often a built-in
part of early engines. Many of those
became victims of the new hot fuels
which promptly melted them.
Arden engines were mentioned briefly,
and one was pictured in this column in
April 2009. They set new standards for
power, lightness, and dependability for
use in smaller models, but I’d like to add
some details of why their performance
was so good.
At our local field, we have a monthly
engine-running session along with our
Saturday OT flying sessions. We recently
ran one of the last model spark-ignition
Arden 19s. That gave us a chance to
study why Arden engines perform so
well.
Ardens are noted as one of the
“snappiest” engines you’ll encounter
when you’re flipping the propeller
without running it. Their basic design
keeps the piston/cylinder combination
almost perfectly round during heating and
cooling cycles. I suspect Ray Arden had
this in mind, but some of it could have
been just a fortunate byproduct of his
chosen design. Either way, the happy
result is an engine that has excellent
compression and little friction whether
running hot or cold.
Rather than being bolted down, the
threaded head screws on, much like the
later Cox engines. Bolted assemblies can
cause small stresses and distortions,
especially in light engines with
comparatively thin cylinders. The
threaded cylinder screws into the
crankcase for the same reason.
The four exhaust openings are evenly
distributed around the circumference of
the cylinder, as opposed to the
asymmetrical porting on almost all other
two-stroke engines. Finally the
connecting rod/piston assembly is a balland-
socket type, similar to Cox engines,
which also stays perfectly round. A
normal wristpin could create a tiny warp
in a piston when heated.
An added touch for minimizing
friction is the roller cam follower. That’s
main body. When the cap was removed,
the reaction between methanol, platinum,
and air would make the wire glow red and
ignite the methanol. Replacing the cap
extinguished it. You didn’t want to lose
the cap in your pocket.
According to Arden’s biography on
the AMA website, the Arden glow plug
first appeared at a contest in 1947, when
Ray showed up selling them out of his car
trunk. Those Arden glow plugs still work
well today. Replaceable wire elements
were available for Arden plugs, but I
don’t recall ever having to replace either
a burned-out element, or any of the other
early glow plugs.
Arden glow plugs are easily identified
at swap meets by their distinctive ballshaped
brass dome on top. You’ll find a
lot more interesting information about
Ray Arden’s life and inventions—he’s
said to have held more than 200 patents—
on the AMA website.
As modelers replaced spark plugs and
ignition systems with the new glow
plugs, an unfortunate thing happened for
today’s engine collectors and OT fliers.
Those ignition systems, and especially
the engines’ breaker point assemblies, hit
the trash cans by the thousands.
Reproduction timer assemblies are
available today for most common
engines, but at higher prices than the
original cost of the entire engine. Clear
a feature I’ve never seen on any other
production engine. The result is that
there’s no perceptible cam “bump” when
you turn the propeller over slowly. Our
test engine turned in excess of 12,000 rpm
on an 8-inch propeller, which is about the
propeller size I’d choose for a small
model.
Arden engines were described in SAM
Speaks issue #105, May/June 1992, in a
series of engine analysis articles by
Charlie Bruce. See the “Sources” list.
Charlie also published a book of those 101
articles he prepared on various engines for
SAM Speaks. He describes in detail each
engine’s construction, followed by
takedown and reassembly sequences. He
runs the engines and gives test results. MA
Sources:
AMA History Program
www.modelaircraft.org/museum/whats
here/history.aspx
SAM Speaks back issues:
Two-CD set: $30 (postpaid in USA) to Karl
Gies
131 13th Avenue South
Lewiston MT 59457
(405) 538-8503
[email protected]
Old Engine Analysis
200-plus page book: $45 (includes US
postage)
CD: $28 (includes US postage)
Charlie Bruce
Edition: Model Aviation - 2011/12
Page Numbers: 129,130,132,133
Edition: Model Aviation - 2011/12
Page Numbers: 129,130,132,133
December 2011 129
GLIDERS wERE
around before
powered flight and
are still used as a
learning tool in
designing powered
aircraft. The
Society of Antique
Modelers (SAM)
organization has competition classes for four glider categories.
Yes, I know, modern glider pilots prefer that they be called
sailplanes, but let’s relax about nomenclature, especially when the
term glider came first.
Three of the glider events are FF and are held at the annual
SAM Champs. They are Hand-Launched Glider, Towline, and
Catapult-Launched Glider. Hand-Launched should be selfexplanatory,
but as I write this, there’s an unsettled rules
discussion about whether wingtip launches will be permanently
permitted. The tip-launch technique tests the fliers’ agility to a
Four Glider events
Old-Timers Bob Angel | [email protected]
Photographer Ned Nevels did some Photoshop work on this photo of Don Bishop’s bomber
takeoff at the flying site in Taft CA. The next OT event there will be in March 2012.
This graceful-looking Albatross glider
was first kitted by Cleveland Models in
1944. Red Scholefield submitted the
photo.
Eric Strengel launches his FF
Playboy at the 2011 Southwest
Regionals held each January in
Eloy AZ. The cars are farther
away than they appear
because of photographer Mike
Woodhouse’s telephoto lens.
Also included in this column:
• Some glow plug history
• Arden engines
higher degree, elevating the competition level over more
conventional launch techniques.
The Catapult event is more docile for many in SAM’s
average age group. The catapult is a simple 6-inch-long dowel
with a 9-inch (unstretched) loop of flat rubber band attached.
One hand holds the dowel and the other holds and releases the
glider. This event obviously favors the flier with the longest
arms, but proxy launches by pet orangutans are specifically
prohibited.
The FF Towline event allows either a 200-foot handheld
towline or a 25-foot hi-start with 150 feet of line attached.
Modern circle tow devices aren’t allowed, but auto rudder is
okay. Glider designs for the FF events must predate 1943.
The RC event is called Old-Timer (OT) Glider, and the rules
allow launch by either hi-start or winch. However, in practice the
pilots usually observe an unwritten agreement to stick to histarts.
Modern “hot” winches, which would elevate the
competition level, require more support equipment and employ
beefier aircraft structures. That would probably result in the
eventual demise of the event.
For each of the four events described, there’s more fine print
in the rule book. As with any competition, you should get the
rules straight before setting out to build a model. Do you
suppose I chose this glider subject just as an excuse to show that
fine-looking Cleveland Albatross photo? The model was kitted
in 1944, so it’s only eligible for the RC event that allows designs
up through 1946.
Ray Arden is generally credited with inventing the glow plug.
But, as with many inventions, there were other contributors—
some were competitors, and some took part as collaborators. In
Ray’s case, he collaborated with Ben Shereshaw, designer of the
Bantam engines, and also Ed Chamberlin. These men probably
took clues from full-scale engine experimenters who used
various “hot plugs” for ignition.
In the early 1900s, model engines provided low power and
were heavy—their weight was measured in pounds, not ounces.
Ray Arden was obsessed with designing smaller, lighter engines
and support equipment. As a teenager, he built his first engine in
his home shop. His ignition system was a vibrating-coil type that
provided a continuous series of sparks. These untimed random
sparks didn’t provide optimum power. At one point, he added an
early glow plug, used along with the continuous spark, to
achieve smoother running.
I once had an accidental acquaintance with vibrating
continuous spark while breaking in an Ohlsson & Rice 23 on a
test stand. The alligator clip on the coil’s point lead popped loose
with the engine running. The clip came to rest, lightly touching
the timer case. It vibrated against the grounded case, producing a
steady stream of sparks. To my surprise the engine continued to
run, slowing very little, until I switched off the battery power.
Before modelers had ever heard of glow plugs, I remember a
new hot fuel that was being marketed as “Liquid Dynamite.”
Through experimentation—and maybe some accidental luck—
Ed, Ben, and Ray found that with this hot fuel you could get an
engine running strongly, then disconnect the spark ignition
system and have the engine continue running. The spark plug’s
side electrode became hot enough to act as a glow plug.
Today, hot plugs occasionally cause problems for OT fliers
when using FAI fuel in spark-ignition engines. The engines don’t
always quit running when the ignition is shut off. Colder spark
plugs usually cure this.
Ray Arden had succeeded in designing and marketing his
small, lightweight engines, starting with the Atom .09 and later
the Arden .09 and Arden 19. He developed lightweight coils and
finally a small FF chassis that integrated the complete ignition
system in a slender plastic package. But those experiments with
Liquid Dynamite had sparked the idea of eliminating the heavy
coil, condenser, batteries, and wiring.
Ray and Ben Shereshaw contributed to developing the final
coiled-wire glow plug. Then a plating of platinum/iridium was
added to the wire to provide more heat through catalytic action.
I recall a vivid demonstration of this
catalytic action in the form of a novel
cigarette lighter that resembled a lipstick
tube. The tube was lined with methanolsaturated
cotton and a platinum-plated
wire was stretched across the top of the
plastic fuel tanks were often a built-in
part of early engines. Many of those
became victims of the new hot fuels
which promptly melted them.
Arden engines were mentioned briefly,
and one was pictured in this column in
April 2009. They set new standards for
power, lightness, and dependability for
use in smaller models, but I’d like to add
some details of why their performance
was so good.
At our local field, we have a monthly
engine-running session along with our
Saturday OT flying sessions. We recently
ran one of the last model spark-ignition
Arden 19s. That gave us a chance to
study why Arden engines perform so
well.
Ardens are noted as one of the
“snappiest” engines you’ll encounter
when you’re flipping the propeller
without running it. Their basic design
keeps the piston/cylinder combination
almost perfectly round during heating and
cooling cycles. I suspect Ray Arden had
this in mind, but some of it could have
been just a fortunate byproduct of his
chosen design. Either way, the happy
result is an engine that has excellent
compression and little friction whether
running hot or cold.
Rather than being bolted down, the
threaded head screws on, much like the
later Cox engines. Bolted assemblies can
cause small stresses and distortions,
especially in light engines with
comparatively thin cylinders. The
threaded cylinder screws into the
crankcase for the same reason.
The four exhaust openings are evenly
distributed around the circumference of
the cylinder, as opposed to the
asymmetrical porting on almost all other
two-stroke engines. Finally the
connecting rod/piston assembly is a balland-
socket type, similar to Cox engines,
which also stays perfectly round. A
normal wristpin could create a tiny warp
in a piston when heated.
An added touch for minimizing
friction is the roller cam follower. That’s
main body. When the cap was removed,
the reaction between methanol, platinum,
and air would make the wire glow red and
ignite the methanol. Replacing the cap
extinguished it. You didn’t want to lose
the cap in your pocket.
According to Arden’s biography on
the AMA website, the Arden glow plug
first appeared at a contest in 1947, when
Ray showed up selling them out of his car
trunk. Those Arden glow plugs still work
well today. Replaceable wire elements
were available for Arden plugs, but I
don’t recall ever having to replace either
a burned-out element, or any of the other
early glow plugs.
Arden glow plugs are easily identified
at swap meets by their distinctive ballshaped
brass dome on top. You’ll find a
lot more interesting information about
Ray Arden’s life and inventions—he’s
said to have held more than 200 patents—
on the AMA website.
As modelers replaced spark plugs and
ignition systems with the new glow
plugs, an unfortunate thing happened for
today’s engine collectors and OT fliers.
Those ignition systems, and especially
the engines’ breaker point assemblies, hit
the trash cans by the thousands.
Reproduction timer assemblies are
available today for most common
engines, but at higher prices than the
original cost of the entire engine. Clear
a feature I’ve never seen on any other
production engine. The result is that
there’s no perceptible cam “bump” when
you turn the propeller over slowly. Our
test engine turned in excess of 12,000 rpm
on an 8-inch propeller, which is about the
propeller size I’d choose for a small
model.
Arden engines were described in SAM
Speaks issue #105, May/June 1992, in a
series of engine analysis articles by
Charlie Bruce. See the “Sources” list.
Charlie also published a book of those 101
articles he prepared on various engines for
SAM Speaks. He describes in detail each
engine’s construction, followed by
takedown and reassembly sequences. He
runs the engines and gives test results. MA
Sources:
AMA History Program
www.modelaircraft.org/museum/whats
here/history.aspx
SAM Speaks back issues:
Two-CD set: $30 (postpaid in USA) to Karl
Gies
131 13th Avenue South
Lewiston MT 59457
(405) 538-8503
[email protected]
Old Engine Analysis
200-plus page book: $45 (includes US
postage)
CD: $28 (includes US postage)
Charlie Bruce
Edition: Model Aviation - 2011/12
Page Numbers: 129,130,132,133
December 2011 129
GLIDERS wERE
around before
powered flight and
are still used as a
learning tool in
designing powered
aircraft. The
Society of Antique
Modelers (SAM)
organization has competition classes for four glider categories.
Yes, I know, modern glider pilots prefer that they be called
sailplanes, but let’s relax about nomenclature, especially when the
term glider came first.
Three of the glider events are FF and are held at the annual
SAM Champs. They are Hand-Launched Glider, Towline, and
Catapult-Launched Glider. Hand-Launched should be selfexplanatory,
but as I write this, there’s an unsettled rules
discussion about whether wingtip launches will be permanently
permitted. The tip-launch technique tests the fliers’ agility to a
Four Glider events
Old-Timers Bob Angel | [email protected]
Photographer Ned Nevels did some Photoshop work on this photo of Don Bishop’s bomber
takeoff at the flying site in Taft CA. The next OT event there will be in March 2012.
This graceful-looking Albatross glider
was first kitted by Cleveland Models in
1944. Red Scholefield submitted the
photo.
Eric Strengel launches his FF
Playboy at the 2011 Southwest
Regionals held each January in
Eloy AZ. The cars are farther
away than they appear
because of photographer Mike
Woodhouse’s telephoto lens.
Also included in this column:
• Some glow plug history
• Arden engines
higher degree, elevating the competition level over more
conventional launch techniques.
The Catapult event is more docile for many in SAM’s
average age group. The catapult is a simple 6-inch-long dowel
with a 9-inch (unstretched) loop of flat rubber band attached.
One hand holds the dowel and the other holds and releases the
glider. This event obviously favors the flier with the longest
arms, but proxy launches by pet orangutans are specifically
prohibited.
The FF Towline event allows either a 200-foot handheld
towline or a 25-foot hi-start with 150 feet of line attached.
Modern circle tow devices aren’t allowed, but auto rudder is
okay. Glider designs for the FF events must predate 1943.
The RC event is called Old-Timer (OT) Glider, and the rules
allow launch by either hi-start or winch. However, in practice the
pilots usually observe an unwritten agreement to stick to histarts.
Modern “hot” winches, which would elevate the
competition level, require more support equipment and employ
beefier aircraft structures. That would probably result in the
eventual demise of the event.
For each of the four events described, there’s more fine print
in the rule book. As with any competition, you should get the
rules straight before setting out to build a model. Do you
suppose I chose this glider subject just as an excuse to show that
fine-looking Cleveland Albatross photo? The model was kitted
in 1944, so it’s only eligible for the RC event that allows designs
up through 1946.
Ray Arden is generally credited with inventing the glow plug.
But, as with many inventions, there were other contributors—
some were competitors, and some took part as collaborators. In
Ray’s case, he collaborated with Ben Shereshaw, designer of the
Bantam engines, and also Ed Chamberlin. These men probably
took clues from full-scale engine experimenters who used
various “hot plugs” for ignition.
In the early 1900s, model engines provided low power and
were heavy—their weight was measured in pounds, not ounces.
Ray Arden was obsessed with designing smaller, lighter engines
and support equipment. As a teenager, he built his first engine in
his home shop. His ignition system was a vibrating-coil type that
provided a continuous series of sparks. These untimed random
sparks didn’t provide optimum power. At one point, he added an
early glow plug, used along with the continuous spark, to
achieve smoother running.
I once had an accidental acquaintance with vibrating
continuous spark while breaking in an Ohlsson & Rice 23 on a
test stand. The alligator clip on the coil’s point lead popped loose
with the engine running. The clip came to rest, lightly touching
the timer case. It vibrated against the grounded case, producing a
steady stream of sparks. To my surprise the engine continued to
run, slowing very little, until I switched off the battery power.
Before modelers had ever heard of glow plugs, I remember a
new hot fuel that was being marketed as “Liquid Dynamite.”
Through experimentation—and maybe some accidental luck—
Ed, Ben, and Ray found that with this hot fuel you could get an
engine running strongly, then disconnect the spark ignition
system and have the engine continue running. The spark plug’s
side electrode became hot enough to act as a glow plug.
Today, hot plugs occasionally cause problems for OT fliers
when using FAI fuel in spark-ignition engines. The engines don’t
always quit running when the ignition is shut off. Colder spark
plugs usually cure this.
Ray Arden had succeeded in designing and marketing his
small, lightweight engines, starting with the Atom .09 and later
the Arden .09 and Arden 19. He developed lightweight coils and
finally a small FF chassis that integrated the complete ignition
system in a slender plastic package. But those experiments with
Liquid Dynamite had sparked the idea of eliminating the heavy
coil, condenser, batteries, and wiring.
Ray and Ben Shereshaw contributed to developing the final
coiled-wire glow plug. Then a plating of platinum/iridium was
added to the wire to provide more heat through catalytic action.
I recall a vivid demonstration of this
catalytic action in the form of a novel
cigarette lighter that resembled a lipstick
tube. The tube was lined with methanolsaturated
cotton and a platinum-plated
wire was stretched across the top of the
plastic fuel tanks were often a built-in
part of early engines. Many of those
became victims of the new hot fuels
which promptly melted them.
Arden engines were mentioned briefly,
and one was pictured in this column in
April 2009. They set new standards for
power, lightness, and dependability for
use in smaller models, but I’d like to add
some details of why their performance
was so good.
At our local field, we have a monthly
engine-running session along with our
Saturday OT flying sessions. We recently
ran one of the last model spark-ignition
Arden 19s. That gave us a chance to
study why Arden engines perform so
well.
Ardens are noted as one of the
“snappiest” engines you’ll encounter
when you’re flipping the propeller
without running it. Their basic design
keeps the piston/cylinder combination
almost perfectly round during heating and
cooling cycles. I suspect Ray Arden had
this in mind, but some of it could have
been just a fortunate byproduct of his
chosen design. Either way, the happy
result is an engine that has excellent
compression and little friction whether
running hot or cold.
Rather than being bolted down, the
threaded head screws on, much like the
later Cox engines. Bolted assemblies can
cause small stresses and distortions,
especially in light engines with
comparatively thin cylinders. The
threaded cylinder screws into the
crankcase for the same reason.
The four exhaust openings are evenly
distributed around the circumference of
the cylinder, as opposed to the
asymmetrical porting on almost all other
two-stroke engines. Finally the
connecting rod/piston assembly is a balland-
socket type, similar to Cox engines,
which also stays perfectly round. A
normal wristpin could create a tiny warp
in a piston when heated.
An added touch for minimizing
friction is the roller cam follower. That’s
main body. When the cap was removed,
the reaction between methanol, platinum,
and air would make the wire glow red and
ignite the methanol. Replacing the cap
extinguished it. You didn’t want to lose
the cap in your pocket.
According to Arden’s biography on
the AMA website, the Arden glow plug
first appeared at a contest in 1947, when
Ray showed up selling them out of his car
trunk. Those Arden glow plugs still work
well today. Replaceable wire elements
were available for Arden plugs, but I
don’t recall ever having to replace either
a burned-out element, or any of the other
early glow plugs.
Arden glow plugs are easily identified
at swap meets by their distinctive ballshaped
brass dome on top. You’ll find a
lot more interesting information about
Ray Arden’s life and inventions—he’s
said to have held more than 200 patents—
on the AMA website.
As modelers replaced spark plugs and
ignition systems with the new glow
plugs, an unfortunate thing happened for
today’s engine collectors and OT fliers.
Those ignition systems, and especially
the engines’ breaker point assemblies, hit
the trash cans by the thousands.
Reproduction timer assemblies are
available today for most common
engines, but at higher prices than the
original cost of the entire engine. Clear
a feature I’ve never seen on any other
production engine. The result is that
there’s no perceptible cam “bump” when
you turn the propeller over slowly. Our
test engine turned in excess of 12,000 rpm
on an 8-inch propeller, which is about the
propeller size I’d choose for a small
model.
Arden engines were described in SAM
Speaks issue #105, May/June 1992, in a
series of engine analysis articles by
Charlie Bruce. See the “Sources” list.
Charlie also published a book of those 101
articles he prepared on various engines for
SAM Speaks. He describes in detail each
engine’s construction, followed by
takedown and reassembly sequences. He
runs the engines and gives test results. MA
Sources:
AMA History Program
www.modelaircraft.org/museum/whats
here/history.aspx
SAM Speaks back issues:
Two-CD set: $30 (postpaid in USA) to Karl
Gies
131 13th Avenue South
Lewiston MT 59457
(405) 538-8503
[email protected]
Old Engine Analysis
200-plus page book: $45 (includes US
postage)
CD: $28 (includes US postage)
Charlie Bruce
Edition: Model Aviation - 2011/12
Page Numbers: 129,130,132,133
December 2011 129
GLIDERS wERE
around before
powered flight and
are still used as a
learning tool in
designing powered
aircraft. The
Society of Antique
Modelers (SAM)
organization has competition classes for four glider categories.
Yes, I know, modern glider pilots prefer that they be called
sailplanes, but let’s relax about nomenclature, especially when the
term glider came first.
Three of the glider events are FF and are held at the annual
SAM Champs. They are Hand-Launched Glider, Towline, and
Catapult-Launched Glider. Hand-Launched should be selfexplanatory,
but as I write this, there’s an unsettled rules
discussion about whether wingtip launches will be permanently
permitted. The tip-launch technique tests the fliers’ agility to a
Four Glider events
Old-Timers Bob Angel | [email protected]
Photographer Ned Nevels did some Photoshop work on this photo of Don Bishop’s bomber
takeoff at the flying site in Taft CA. The next OT event there will be in March 2012.
This graceful-looking Albatross glider
was first kitted by Cleveland Models in
1944. Red Scholefield submitted the
photo.
Eric Strengel launches his FF
Playboy at the 2011 Southwest
Regionals held each January in
Eloy AZ. The cars are farther
away than they appear
because of photographer Mike
Woodhouse’s telephoto lens.
Also included in this column:
• Some glow plug history
• Arden engines
higher degree, elevating the competition level over more
conventional launch techniques.
The Catapult event is more docile for many in SAM’s
average age group. The catapult is a simple 6-inch-long dowel
with a 9-inch (unstretched) loop of flat rubber band attached.
One hand holds the dowel and the other holds and releases the
glider. This event obviously favors the flier with the longest
arms, but proxy launches by pet orangutans are specifically
prohibited.
The FF Towline event allows either a 200-foot handheld
towline or a 25-foot hi-start with 150 feet of line attached.
Modern circle tow devices aren’t allowed, but auto rudder is
okay. Glider designs for the FF events must predate 1943.
The RC event is called Old-Timer (OT) Glider, and the rules
allow launch by either hi-start or winch. However, in practice the
pilots usually observe an unwritten agreement to stick to histarts.
Modern “hot” winches, which would elevate the
competition level, require more support equipment and employ
beefier aircraft structures. That would probably result in the
eventual demise of the event.
For each of the four events described, there’s more fine print
in the rule book. As with any competition, you should get the
rules straight before setting out to build a model. Do you
suppose I chose this glider subject just as an excuse to show that
fine-looking Cleveland Albatross photo? The model was kitted
in 1944, so it’s only eligible for the RC event that allows designs
up through 1946.
Ray Arden is generally credited with inventing the glow plug.
But, as with many inventions, there were other contributors—
some were competitors, and some took part as collaborators. In
Ray’s case, he collaborated with Ben Shereshaw, designer of the
Bantam engines, and also Ed Chamberlin. These men probably
took clues from full-scale engine experimenters who used
various “hot plugs” for ignition.
In the early 1900s, model engines provided low power and
were heavy—their weight was measured in pounds, not ounces.
Ray Arden was obsessed with designing smaller, lighter engines
and support equipment. As a teenager, he built his first engine in
his home shop. His ignition system was a vibrating-coil type that
provided a continuous series of sparks. These untimed random
sparks didn’t provide optimum power. At one point, he added an
early glow plug, used along with the continuous spark, to
achieve smoother running.
I once had an accidental acquaintance with vibrating
continuous spark while breaking in an Ohlsson & Rice 23 on a
test stand. The alligator clip on the coil’s point lead popped loose
with the engine running. The clip came to rest, lightly touching
the timer case. It vibrated against the grounded case, producing a
steady stream of sparks. To my surprise the engine continued to
run, slowing very little, until I switched off the battery power.
Before modelers had ever heard of glow plugs, I remember a
new hot fuel that was being marketed as “Liquid Dynamite.”
Through experimentation—and maybe some accidental luck—
Ed, Ben, and Ray found that with this hot fuel you could get an
engine running strongly, then disconnect the spark ignition
system and have the engine continue running. The spark plug’s
side electrode became hot enough to act as a glow plug.
Today, hot plugs occasionally cause problems for OT fliers
when using FAI fuel in spark-ignition engines. The engines don’t
always quit running when the ignition is shut off. Colder spark
plugs usually cure this.
Ray Arden had succeeded in designing and marketing his
small, lightweight engines, starting with the Atom .09 and later
the Arden .09 and Arden 19. He developed lightweight coils and
finally a small FF chassis that integrated the complete ignition
system in a slender plastic package. But those experiments with
Liquid Dynamite had sparked the idea of eliminating the heavy
coil, condenser, batteries, and wiring.
Ray and Ben Shereshaw contributed to developing the final
coiled-wire glow plug. Then a plating of platinum/iridium was
added to the wire to provide more heat through catalytic action.
I recall a vivid demonstration of this
catalytic action in the form of a novel
cigarette lighter that resembled a lipstick
tube. The tube was lined with methanolsaturated
cotton and a platinum-plated
wire was stretched across the top of the
plastic fuel tanks were often a built-in
part of early engines. Many of those
became victims of the new hot fuels
which promptly melted them.
Arden engines were mentioned briefly,
and one was pictured in this column in
April 2009. They set new standards for
power, lightness, and dependability for
use in smaller models, but I’d like to add
some details of why their performance
was so good.
At our local field, we have a monthly
engine-running session along with our
Saturday OT flying sessions. We recently
ran one of the last model spark-ignition
Arden 19s. That gave us a chance to
study why Arden engines perform so
well.
Ardens are noted as one of the
“snappiest” engines you’ll encounter
when you’re flipping the propeller
without running it. Their basic design
keeps the piston/cylinder combination
almost perfectly round during heating and
cooling cycles. I suspect Ray Arden had
this in mind, but some of it could have
been just a fortunate byproduct of his
chosen design. Either way, the happy
result is an engine that has excellent
compression and little friction whether
running hot or cold.
Rather than being bolted down, the
threaded head screws on, much like the
later Cox engines. Bolted assemblies can
cause small stresses and distortions,
especially in light engines with
comparatively thin cylinders. The
threaded cylinder screws into the
crankcase for the same reason.
The four exhaust openings are evenly
distributed around the circumference of
the cylinder, as opposed to the
asymmetrical porting on almost all other
two-stroke engines. Finally the
connecting rod/piston assembly is a balland-
socket type, similar to Cox engines,
which also stays perfectly round. A
normal wristpin could create a tiny warp
in a piston when heated.
An added touch for minimizing
friction is the roller cam follower. That’s
main body. When the cap was removed,
the reaction between methanol, platinum,
and air would make the wire glow red and
ignite the methanol. Replacing the cap
extinguished it. You didn’t want to lose
the cap in your pocket.
According to Arden’s biography on
the AMA website, the Arden glow plug
first appeared at a contest in 1947, when
Ray showed up selling them out of his car
trunk. Those Arden glow plugs still work
well today. Replaceable wire elements
were available for Arden plugs, but I
don’t recall ever having to replace either
a burned-out element, or any of the other
early glow plugs.
Arden glow plugs are easily identified
at swap meets by their distinctive ballshaped
brass dome on top. You’ll find a
lot more interesting information about
Ray Arden’s life and inventions—he’s
said to have held more than 200 patents—
on the AMA website.
As modelers replaced spark plugs and
ignition systems with the new glow
plugs, an unfortunate thing happened for
today’s engine collectors and OT fliers.
Those ignition systems, and especially
the engines’ breaker point assemblies, hit
the trash cans by the thousands.
Reproduction timer assemblies are
available today for most common
engines, but at higher prices than the
original cost of the entire engine. Clear
a feature I’ve never seen on any other
production engine. The result is that
there’s no perceptible cam “bump” when
you turn the propeller over slowly. Our
test engine turned in excess of 12,000 rpm
on an 8-inch propeller, which is about the
propeller size I’d choose for a small
model.
Arden engines were described in SAM
Speaks issue #105, May/June 1992, in a
series of engine analysis articles by
Charlie Bruce. See the “Sources” list.
Charlie also published a book of those 101
articles he prepared on various engines for
SAM Speaks. He describes in detail each
engine’s construction, followed by
takedown and reassembly sequences. He
runs the engines and gives test results. MA
Sources:
AMA History Program
www.modelaircraft.org/museum/whats
here/history.aspx
SAM Speaks back issues:
Two-CD set: $30 (postpaid in USA) to Karl
Gies
131 13th Avenue South
Lewiston MT 59457
(405) 538-8503
[email protected]
Old Engine Analysis
200-plus page book: $45 (includes US
postage)
CD: $28 (includes US postage)
Charlie Bruce
