80 MODEL AVIATION
Joe Wagner The Engine Shop | [email protected]
Also included in this column:
• Enya availability
• Freeing a stuck wrist pin
• Dummy radial engines
Evolution trainer power system
Above: Horizon Hobby’s Evolution
Trainer Power System was specifically
designed for novice RC pilots. It has
several unique features and all of them
work!
Left: The Evolution Trainer Power
System comes with a three-blade
propel ler, spinner, muf f ler, Al len
wrenches, and two types of propeller
driver, one with a flywheel.
Below left: The Evolution .46 in action. It
has the widest rpm range of any RC
engine Joe has ever run—1,650 to
16,500—right out of the box, without
break-in.
Since Horizon Hobby released its exceptionally innovative
Evolution Trainer Power System .46 RC engines, I’ve been
curious—and a little skeptical—about its unusual features. Recently
I was able to obtain one of those units to test, and I’m no longer
skeptical!
The Evolution .46 is supplied with a special 10-inch, three-blade
propeller and a sturdy 2¼-inch plastic spinner. Also, the propeller
driver that comes on the engine features an attached 11/2-ounce steel
flywheel.
That, plus the masses of the propeller and spinner (31/4 ounces
total), provides plenty of rotational inertia to ensure smooth and
reliable idling. The Evolution .46 has the lowest dependable idle rpm
of any glow engine I’ve handled.
The Evolution’s user guide booklet reads, “Every Evolution
engine has been test run and adjusted at the factory, and is ready to
fly with no adjustments or break-in required.” I found that hard to
believe. Yet it turned out to be true.
One criterion for establishing whether or not a model engine is
properly broken in and fully ready for powering a model is its idling
performance. In general, after an engine has been run for an hour or
so, its reliable idling speed will decrease noticeably. That didn’t
happen with the Evolution.
04sig3.QXD_00MSTRPG.QXD 2/23/10 9:55 AM Page 80
April 2010 81
prefer starting by hand when I test a new
engine. I can learn a lot from the “feel” of
hand-flipping. And with a leather glove to
protect my fingers, that’s proved to be quite
safe. However, I was leery of that threeblade
propeller!
Back in the good old days, I suffered
many a sharp rap on the knuckles while
trying to hand-start spark-ignition engines
equipped with three-blade X-Cell
propellers, but the Evolution’s three-blade
gave me no trouble.
Maybe it was the spinner’s presence, but
I had no knuckle-rap problems in any of the
two-dozen-plus hand starts I performed on
the Evolution .46. It truly is an easy-starting
engine!
I admit that I did encounter a few minor
difficulties with my Evolution .46. One was
a bit of molding flash on the propeller and
spinner parts.
As I routinely do with all of my plastic
propellers, I scraped and draw-filed the
sharp LEs to smoothly rounded contours
and barely removed the sharp burr from the
TEs. Don’t round model propellers’ TEs.
That can make them noticeably less
efficient—and noisier.
The Evolution’s spinner fits tightly into
its backplate, and the slight molding flash
on those parts kept them from fitting
together. I used a sharp jeweler’s file and
stroked sideways (that’s what draw-filing is)
to eliminate the problem.
The Evolution instructions call for
employing an open-end wrench for
tightening the prop nut. I used a die-cast
“plus sign” propeller wrench, as I’ve usually
done on my model engines.
I found out why that’s not a good idea on
the Evolution. Although I have a strong
grip, I found it impossible to tighten the
Evolution’s prop nut hard enough to stop it
from loosening.
Following the instructions eliminated
that problem. I’d say that at least an 8-inch
Crescent wrench is needed to get the
Evolution’s prop nut tight. Adding a bit of
blue Loctite before installing the nut on the
crankshaft might be good insurance too.
I received an e-mail from John Ashcraft
(Collinsville, Illinois), asking about the
availability of Enya model engines in the
US. I used to like Enyas a lot and bought
several in the 20th century. But the old
importer—Model Rectifier Corporation—no
longer carries these engines.
From its first tank of fuel to the sixth, the
Evolution’s idling speed remained the same.
I could hardly believe it; all the way down to
1,650 rpm—with an immediate nohesitation
increase as soon as I opened the
throttle. Every time too!
The Evolution’s needle-valve adjustment
is restricted to just under a single turn. The
“factory setting” worked out perfectly for
me.
My home’s altitude is 470 feet above
MSL. For fliers who live at higher
elevations such as Denver, Colorado, and
Albuquerque, New Mexico, the Evolution’s
manual describes how to adjust the
carburetor needles to compensate for the
density altitude difference.
Of course, the fuel used can make a
difference too. The recommended fuel for
the Evolution engine is 10%-15%-nitrocontent,
commercial glow fuel as supplied
by Cool Power, Omega, Hangar 9 Aero
Blend, or Powermaster.
I used 15% Maxy’s Fuel, which has 15%
nitro and 22% oil content. The oil is a 50-50
mixture of castor and synthetic. That worked
fine for my Evolution.
The Evolution’s three-blade moldedplastic
propeller has a rather low pitch. The
manual claims that it’s not only quieter than
the usual two-blade propeller that this size
engine customarily spins, but it also
provides more consistent flight performance
in maneuvers. I’ll go along with that.
Since the 1950s, I’ve preferred to fly my
CL Precision Aerobatics models with lowpitch
propellers. That way the flight speed
doesn’t vary much in climbs and dives and
makes for more consistent control effect.
Now for startup! As I’ve mentioned
several times in previous columns, I much
Gun shops and Wal-Mart sell Hoppe’s #9 Solvent. It’s a useful
penetrant for loosening jammed wrist pins and other stuck-tight
model engine parts.
Vacuum-formed dummy radial engines, such as this Kinner, are
widely used in electric-powered scale models. With proper care,
they also work in engine-powered models.
This sweet-running Enya .09-IV T.V. is no
longer available. However, larger Enyas (.15-
.60) are still being imported into the US.
04sig3.QXD_00MSTRPG.QXD 2/23/10 9:56 AM Page 81
I tried an online search without success.
Then I replied to John with that dismal
information.
However, Bob Hunt, MA’s former
editor, found us a US source for Enyas!
Randy Smith of Aero Products imports
them. The smaller Enyas aren’t on Randy’s
list; there are no .049s, .061s, .09s, or
diesels. But he does carry .15-.60 twostrokes
and a .53 four-stroke.
In the February column, I recommended
two commercial fluids that I’ve found to be
exceptionally helpful in model engine repair
and maintenance: Dawn Power Dissolver
and Marvel Mystery Oil. However, there’s
one tough engine problem that neither of
those is much help with: snug-fitting parts
that are rusted together or glued with
congealed castor oil, such as wrist pins.
The problem is that the solvents I
recommended cannot penetrate into the
microscopic clearances between stuck parts.
The only solvent I know of that could help
loosen a stuck-in-place wrist pin from a
model engine piston was Hoppe’s #9
Solvent. That’s been a gun owner’s
standard cleaning fluid for decades.
Hoppe’s does help in model engine
work, but it still takes a fair amount of force
to separate the pin from the piston. And that
risks damage to the parts.
But two readers recently referred me to
a series of tests reported in the April 2007
Machinist’s Workshop magazine. In those,
the testers measured the “rusted joint
releasing ability” of several solvents and
lubricants, including WD-40 and Liquid
Wrench. Then they compared their
performance with a home-brew of half
acetone and half automatic transmission
fluid.
Liquid Wrench worked twice as well as
WD-40—but the ATF-Acetone mix was
four times as effective as Liquid Wrench!
I’ve got to try that stuff now. I hate taking
the chance of spoiling a long-out-ofproduction
model engine by hammering
on a drift punch to drive a steel wrist pin
out of a cast-iron piston.
On a recent visit to a fellow magazine
columnist, Pat Tritle, in Albuquerque,
New Mexico, I saw a lovely dummy
Kinner five-cylinder engine in the nose of
his scale Fleet Trailer biplane. Then I was
pleased to learn from Pat that it was made
from an inexpensive vacuum-formed set
of “halves” that is available from Keith
“Sparky” Sparks—doing business as
ParkFlyer Plastics—in Fort Worth, Texas.
Sparky’s Web site has an amazing list
of dummy radial and inline aircraft
engines. They include Wright Whirlwindlike,
seven- and nine-cylinder radials in
12-inch diameters that are suitable for 1/4-
scale projects; 31/2-inch-diameter sevenand
nine-cylinder P&W Wasps for 1/2A
power; and a 6-inch-diameter, fivecylinder
Kinner that caught my eye.
Sparky’s products follow a short-kit
form. They include just front and back
vacuum-formed engine halves that the
builder needs to glue together, paint, and
dress up with wood, wires, and aluminum
tubing, to simulate pushrods, exhaust
pipes, and spark-ignition components.
Instructions are available on the
ParkFlyer Plastics Web site. The result is
lightweight, reasonably sturdy, and
extraordinarily realistic. MA
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
ParkFlyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Maxy’s Pro Racing Fuel (Stanley Jackson)
(305) 299-3578
www.maxysfuel.com
Edition: Model Aviation - 2010/04
Page Numbers: 80,81,82
Edition: Model Aviation - 2010/04
Page Numbers: 80,81,82
80 MODEL AVIATION
Joe Wagner The Engine Shop | [email protected]
Also included in this column:
• Enya availability
• Freeing a stuck wrist pin
• Dummy radial engines
Evolution trainer power system
Above: Horizon Hobby’s Evolution
Trainer Power System was specifically
designed for novice RC pilots. It has
several unique features and all of them
work!
Left: The Evolution Trainer Power
System comes with a three-blade
propel ler, spinner, muf f ler, Al len
wrenches, and two types of propeller
driver, one with a flywheel.
Below left: The Evolution .46 in action. It
has the widest rpm range of any RC
engine Joe has ever run—1,650 to
16,500—right out of the box, without
break-in.
Since Horizon Hobby released its exceptionally innovative
Evolution Trainer Power System .46 RC engines, I’ve been
curious—and a little skeptical—about its unusual features. Recently
I was able to obtain one of those units to test, and I’m no longer
skeptical!
The Evolution .46 is supplied with a special 10-inch, three-blade
propeller and a sturdy 2¼-inch plastic spinner. Also, the propeller
driver that comes on the engine features an attached 11/2-ounce steel
flywheel.
That, plus the masses of the propeller and spinner (31/4 ounces
total), provides plenty of rotational inertia to ensure smooth and
reliable idling. The Evolution .46 has the lowest dependable idle rpm
of any glow engine I’ve handled.
The Evolution’s user guide booklet reads, “Every Evolution
engine has been test run and adjusted at the factory, and is ready to
fly with no adjustments or break-in required.” I found that hard to
believe. Yet it turned out to be true.
One criterion for establishing whether or not a model engine is
properly broken in and fully ready for powering a model is its idling
performance. In general, after an engine has been run for an hour or
so, its reliable idling speed will decrease noticeably. That didn’t
happen with the Evolution.
04sig3.QXD_00MSTRPG.QXD 2/23/10 9:55 AM Page 80
April 2010 81
prefer starting by hand when I test a new
engine. I can learn a lot from the “feel” of
hand-flipping. And with a leather glove to
protect my fingers, that’s proved to be quite
safe. However, I was leery of that threeblade
propeller!
Back in the good old days, I suffered
many a sharp rap on the knuckles while
trying to hand-start spark-ignition engines
equipped with three-blade X-Cell
propellers, but the Evolution’s three-blade
gave me no trouble.
Maybe it was the spinner’s presence, but
I had no knuckle-rap problems in any of the
two-dozen-plus hand starts I performed on
the Evolution .46. It truly is an easy-starting
engine!
I admit that I did encounter a few minor
difficulties with my Evolution .46. One was
a bit of molding flash on the propeller and
spinner parts.
As I routinely do with all of my plastic
propellers, I scraped and draw-filed the
sharp LEs to smoothly rounded contours
and barely removed the sharp burr from the
TEs. Don’t round model propellers’ TEs.
That can make them noticeably less
efficient—and noisier.
The Evolution’s spinner fits tightly into
its backplate, and the slight molding flash
on those parts kept them from fitting
together. I used a sharp jeweler’s file and
stroked sideways (that’s what draw-filing is)
to eliminate the problem.
The Evolution instructions call for
employing an open-end wrench for
tightening the prop nut. I used a die-cast
“plus sign” propeller wrench, as I’ve usually
done on my model engines.
I found out why that’s not a good idea on
the Evolution. Although I have a strong
grip, I found it impossible to tighten the
Evolution’s prop nut hard enough to stop it
from loosening.
Following the instructions eliminated
that problem. I’d say that at least an 8-inch
Crescent wrench is needed to get the
Evolution’s prop nut tight. Adding a bit of
blue Loctite before installing the nut on the
crankshaft might be good insurance too.
I received an e-mail from John Ashcraft
(Collinsville, Illinois), asking about the
availability of Enya model engines in the
US. I used to like Enyas a lot and bought
several in the 20th century. But the old
importer—Model Rectifier Corporation—no
longer carries these engines.
From its first tank of fuel to the sixth, the
Evolution’s idling speed remained the same.
I could hardly believe it; all the way down to
1,650 rpm—with an immediate nohesitation
increase as soon as I opened the
throttle. Every time too!
The Evolution’s needle-valve adjustment
is restricted to just under a single turn. The
“factory setting” worked out perfectly for
me.
My home’s altitude is 470 feet above
MSL. For fliers who live at higher
elevations such as Denver, Colorado, and
Albuquerque, New Mexico, the Evolution’s
manual describes how to adjust the
carburetor needles to compensate for the
density altitude difference.
Of course, the fuel used can make a
difference too. The recommended fuel for
the Evolution engine is 10%-15%-nitrocontent,
commercial glow fuel as supplied
by Cool Power, Omega, Hangar 9 Aero
Blend, or Powermaster.
I used 15% Maxy’s Fuel, which has 15%
nitro and 22% oil content. The oil is a 50-50
mixture of castor and synthetic. That worked
fine for my Evolution.
The Evolution’s three-blade moldedplastic
propeller has a rather low pitch. The
manual claims that it’s not only quieter than
the usual two-blade propeller that this size
engine customarily spins, but it also
provides more consistent flight performance
in maneuvers. I’ll go along with that.
Since the 1950s, I’ve preferred to fly my
CL Precision Aerobatics models with lowpitch
propellers. That way the flight speed
doesn’t vary much in climbs and dives and
makes for more consistent control effect.
Now for startup! As I’ve mentioned
several times in previous columns, I much
Gun shops and Wal-Mart sell Hoppe’s #9 Solvent. It’s a useful
penetrant for loosening jammed wrist pins and other stuck-tight
model engine parts.
Vacuum-formed dummy radial engines, such as this Kinner, are
widely used in electric-powered scale models. With proper care,
they also work in engine-powered models.
This sweet-running Enya .09-IV T.V. is no
longer available. However, larger Enyas (.15-
.60) are still being imported into the US.
04sig3.QXD_00MSTRPG.QXD 2/23/10 9:56 AM Page 81
I tried an online search without success.
Then I replied to John with that dismal
information.
However, Bob Hunt, MA’s former
editor, found us a US source for Enyas!
Randy Smith of Aero Products imports
them. The smaller Enyas aren’t on Randy’s
list; there are no .049s, .061s, .09s, or
diesels. But he does carry .15-.60 twostrokes
and a .53 four-stroke.
In the February column, I recommended
two commercial fluids that I’ve found to be
exceptionally helpful in model engine repair
and maintenance: Dawn Power Dissolver
and Marvel Mystery Oil. However, there’s
one tough engine problem that neither of
those is much help with: snug-fitting parts
that are rusted together or glued with
congealed castor oil, such as wrist pins.
The problem is that the solvents I
recommended cannot penetrate into the
microscopic clearances between stuck parts.
The only solvent I know of that could help
loosen a stuck-in-place wrist pin from a
model engine piston was Hoppe’s #9
Solvent. That’s been a gun owner’s
standard cleaning fluid for decades.
Hoppe’s does help in model engine
work, but it still takes a fair amount of force
to separate the pin from the piston. And that
risks damage to the parts.
But two readers recently referred me to
a series of tests reported in the April 2007
Machinist’s Workshop magazine. In those,
the testers measured the “rusted joint
releasing ability” of several solvents and
lubricants, including WD-40 and Liquid
Wrench. Then they compared their
performance with a home-brew of half
acetone and half automatic transmission
fluid.
Liquid Wrench worked twice as well as
WD-40—but the ATF-Acetone mix was
four times as effective as Liquid Wrench!
I’ve got to try that stuff now. I hate taking
the chance of spoiling a long-out-ofproduction
model engine by hammering
on a drift punch to drive a steel wrist pin
out of a cast-iron piston.
On a recent visit to a fellow magazine
columnist, Pat Tritle, in Albuquerque,
New Mexico, I saw a lovely dummy
Kinner five-cylinder engine in the nose of
his scale Fleet Trailer biplane. Then I was
pleased to learn from Pat that it was made
from an inexpensive vacuum-formed set
of “halves” that is available from Keith
“Sparky” Sparks—doing business as
ParkFlyer Plastics—in Fort Worth, Texas.
Sparky’s Web site has an amazing list
of dummy radial and inline aircraft
engines. They include Wright Whirlwindlike,
seven- and nine-cylinder radials in
12-inch diameters that are suitable for 1/4-
scale projects; 31/2-inch-diameter sevenand
nine-cylinder P&W Wasps for 1/2A
power; and a 6-inch-diameter, fivecylinder
Kinner that caught my eye.
Sparky’s products follow a short-kit
form. They include just front and back
vacuum-formed engine halves that the
builder needs to glue together, paint, and
dress up with wood, wires, and aluminum
tubing, to simulate pushrods, exhaust
pipes, and spark-ignition components.
Instructions are available on the
ParkFlyer Plastics Web site. The result is
lightweight, reasonably sturdy, and
extraordinarily realistic. MA
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
ParkFlyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Maxy’s Pro Racing Fuel (Stanley Jackson)
(305) 299-3578
www.maxysfuel.com
Edition: Model Aviation - 2010/04
Page Numbers: 80,81,82
80 MODEL AVIATION
Joe Wagner The Engine Shop | [email protected]
Also included in this column:
• Enya availability
• Freeing a stuck wrist pin
• Dummy radial engines
Evolution trainer power system
Above: Horizon Hobby’s Evolution
Trainer Power System was specifically
designed for novice RC pilots. It has
several unique features and all of them
work!
Left: The Evolution Trainer Power
System comes with a three-blade
propel ler, spinner, muf f ler, Al len
wrenches, and two types of propeller
driver, one with a flywheel.
Below left: The Evolution .46 in action. It
has the widest rpm range of any RC
engine Joe has ever run—1,650 to
16,500—right out of the box, without
break-in.
Since Horizon Hobby released its exceptionally innovative
Evolution Trainer Power System .46 RC engines, I’ve been
curious—and a little skeptical—about its unusual features. Recently
I was able to obtain one of those units to test, and I’m no longer
skeptical!
The Evolution .46 is supplied with a special 10-inch, three-blade
propeller and a sturdy 2¼-inch plastic spinner. Also, the propeller
driver that comes on the engine features an attached 11/2-ounce steel
flywheel.
That, plus the masses of the propeller and spinner (31/4 ounces
total), provides plenty of rotational inertia to ensure smooth and
reliable idling. The Evolution .46 has the lowest dependable idle rpm
of any glow engine I’ve handled.
The Evolution’s user guide booklet reads, “Every Evolution
engine has been test run and adjusted at the factory, and is ready to
fly with no adjustments or break-in required.” I found that hard to
believe. Yet it turned out to be true.
One criterion for establishing whether or not a model engine is
properly broken in and fully ready for powering a model is its idling
performance. In general, after an engine has been run for an hour or
so, its reliable idling speed will decrease noticeably. That didn’t
happen with the Evolution.
04sig3.QXD_00MSTRPG.QXD 2/23/10 9:55 AM Page 80
April 2010 81
prefer starting by hand when I test a new
engine. I can learn a lot from the “feel” of
hand-flipping. And with a leather glove to
protect my fingers, that’s proved to be quite
safe. However, I was leery of that threeblade
propeller!
Back in the good old days, I suffered
many a sharp rap on the knuckles while
trying to hand-start spark-ignition engines
equipped with three-blade X-Cell
propellers, but the Evolution’s three-blade
gave me no trouble.
Maybe it was the spinner’s presence, but
I had no knuckle-rap problems in any of the
two-dozen-plus hand starts I performed on
the Evolution .46. It truly is an easy-starting
engine!
I admit that I did encounter a few minor
difficulties with my Evolution .46. One was
a bit of molding flash on the propeller and
spinner parts.
As I routinely do with all of my plastic
propellers, I scraped and draw-filed the
sharp LEs to smoothly rounded contours
and barely removed the sharp burr from the
TEs. Don’t round model propellers’ TEs.
That can make them noticeably less
efficient—and noisier.
The Evolution’s spinner fits tightly into
its backplate, and the slight molding flash
on those parts kept them from fitting
together. I used a sharp jeweler’s file and
stroked sideways (that’s what draw-filing is)
to eliminate the problem.
The Evolution instructions call for
employing an open-end wrench for
tightening the prop nut. I used a die-cast
“plus sign” propeller wrench, as I’ve usually
done on my model engines.
I found out why that’s not a good idea on
the Evolution. Although I have a strong
grip, I found it impossible to tighten the
Evolution’s prop nut hard enough to stop it
from loosening.
Following the instructions eliminated
that problem. I’d say that at least an 8-inch
Crescent wrench is needed to get the
Evolution’s prop nut tight. Adding a bit of
blue Loctite before installing the nut on the
crankshaft might be good insurance too.
I received an e-mail from John Ashcraft
(Collinsville, Illinois), asking about the
availability of Enya model engines in the
US. I used to like Enyas a lot and bought
several in the 20th century. But the old
importer—Model Rectifier Corporation—no
longer carries these engines.
From its first tank of fuel to the sixth, the
Evolution’s idling speed remained the same.
I could hardly believe it; all the way down to
1,650 rpm—with an immediate nohesitation
increase as soon as I opened the
throttle. Every time too!
The Evolution’s needle-valve adjustment
is restricted to just under a single turn. The
“factory setting” worked out perfectly for
me.
My home’s altitude is 470 feet above
MSL. For fliers who live at higher
elevations such as Denver, Colorado, and
Albuquerque, New Mexico, the Evolution’s
manual describes how to adjust the
carburetor needles to compensate for the
density altitude difference.
Of course, the fuel used can make a
difference too. The recommended fuel for
the Evolution engine is 10%-15%-nitrocontent,
commercial glow fuel as supplied
by Cool Power, Omega, Hangar 9 Aero
Blend, or Powermaster.
I used 15% Maxy’s Fuel, which has 15%
nitro and 22% oil content. The oil is a 50-50
mixture of castor and synthetic. That worked
fine for my Evolution.
The Evolution’s three-blade moldedplastic
propeller has a rather low pitch. The
manual claims that it’s not only quieter than
the usual two-blade propeller that this size
engine customarily spins, but it also
provides more consistent flight performance
in maneuvers. I’ll go along with that.
Since the 1950s, I’ve preferred to fly my
CL Precision Aerobatics models with lowpitch
propellers. That way the flight speed
doesn’t vary much in climbs and dives and
makes for more consistent control effect.
Now for startup! As I’ve mentioned
several times in previous columns, I much
Gun shops and Wal-Mart sell Hoppe’s #9 Solvent. It’s a useful
penetrant for loosening jammed wrist pins and other stuck-tight
model engine parts.
Vacuum-formed dummy radial engines, such as this Kinner, are
widely used in electric-powered scale models. With proper care,
they also work in engine-powered models.
This sweet-running Enya .09-IV T.V. is no
longer available. However, larger Enyas (.15-
.60) are still being imported into the US.
04sig3.QXD_00MSTRPG.QXD 2/23/10 9:56 AM Page 81
I tried an online search without success.
Then I replied to John with that dismal
information.
However, Bob Hunt, MA’s former
editor, found us a US source for Enyas!
Randy Smith of Aero Products imports
them. The smaller Enyas aren’t on Randy’s
list; there are no .049s, .061s, .09s, or
diesels. But he does carry .15-.60 twostrokes
and a .53 four-stroke.
In the February column, I recommended
two commercial fluids that I’ve found to be
exceptionally helpful in model engine repair
and maintenance: Dawn Power Dissolver
and Marvel Mystery Oil. However, there’s
one tough engine problem that neither of
those is much help with: snug-fitting parts
that are rusted together or glued with
congealed castor oil, such as wrist pins.
The problem is that the solvents I
recommended cannot penetrate into the
microscopic clearances between stuck parts.
The only solvent I know of that could help
loosen a stuck-in-place wrist pin from a
model engine piston was Hoppe’s #9
Solvent. That’s been a gun owner’s
standard cleaning fluid for decades.
Hoppe’s does help in model engine
work, but it still takes a fair amount of force
to separate the pin from the piston. And that
risks damage to the parts.
But two readers recently referred me to
a series of tests reported in the April 2007
Machinist’s Workshop magazine. In those,
the testers measured the “rusted joint
releasing ability” of several solvents and
lubricants, including WD-40 and Liquid
Wrench. Then they compared their
performance with a home-brew of half
acetone and half automatic transmission
fluid.
Liquid Wrench worked twice as well as
WD-40—but the ATF-Acetone mix was
four times as effective as Liquid Wrench!
I’ve got to try that stuff now. I hate taking
the chance of spoiling a long-out-ofproduction
model engine by hammering
on a drift punch to drive a steel wrist pin
out of a cast-iron piston.
On a recent visit to a fellow magazine
columnist, Pat Tritle, in Albuquerque,
New Mexico, I saw a lovely dummy
Kinner five-cylinder engine in the nose of
his scale Fleet Trailer biplane. Then I was
pleased to learn from Pat that it was made
from an inexpensive vacuum-formed set
of “halves” that is available from Keith
“Sparky” Sparks—doing business as
ParkFlyer Plastics—in Fort Worth, Texas.
Sparky’s Web site has an amazing list
of dummy radial and inline aircraft
engines. They include Wright Whirlwindlike,
seven- and nine-cylinder radials in
12-inch diameters that are suitable for 1/4-
scale projects; 31/2-inch-diameter sevenand
nine-cylinder P&W Wasps for 1/2A
power; and a 6-inch-diameter, fivecylinder
Kinner that caught my eye.
Sparky’s products follow a short-kit
form. They include just front and back
vacuum-formed engine halves that the
builder needs to glue together, paint, and
dress up with wood, wires, and aluminum
tubing, to simulate pushrods, exhaust
pipes, and spark-ignition components.
Instructions are available on the
ParkFlyer Plastics Web site. The result is
lightweight, reasonably sturdy, and
extraordinarily realistic. MA
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
ParkFlyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Maxy’s Pro Racing Fuel (Stanley Jackson)
(305) 299-3578
www.maxysfuel.com
