ONCE IN AWHILE when I receive a new
engine to test and report on to you, it arrives
accompanied by accessories. The Evolution
.36 I recently acquired from Hangar 9 did,
but those “accessories” turned out to be a
complete kit for an ARF CL model—including handle and lines.
The engine itself came with several extras. Two different style
mufflers are provided. One is the conventional sort, with a large
expansion chamber. The other is a much smaller “tongue-type”—so
called (I think) because it resembles a rectangular gray tongue
sticking out of the exhaust port’s “mouth.”
Three venturis come with the Evolution .36. That’s evidently to
make the engine adaptable to a wide range of model sizes. This is a
CL power plant without a throttle. But the venturis are of different
lengths and bore sizes.
By interchanging them, the user can vary the engine’s speed and
power output. The longest venturi has the smallest ID and puts out
the lowest rpm. It was installed on the Evolution .36 I received.
Other Evolution .36 extras were a spinner nut, three-blade
propeller, complete mounting hardware—and all of the various
Allen wrenches needed for engine and airframe assembly.
However, one notable omission in this otherwise complete package
was operation instructions. That struck me as odd, because
Evolution engines have several special features that surely deserve
to be brought to the buyer’s attention. One is that they require no
break-in.
The User Guide booklet for the Evolution .46 RC that I tested
and reported on in this column early this year 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.” My tests on it
verified that.
I installed the engine on my test stand and checked its
performance before and after running six tanks of fuel through it.
Top speed and lowest reliable idle rpm remained essentially the
same throughout.
I did similar bench-testing with the Evolution .36. Out of the box
it hand-started remarkably easily when cold, but it showed some
balkiness when I tried hot restarts. Six tanks of fuel showed no
change in performance.
I tested both mufflers—and was surprised to learn that the tongue
version’s sound output turned out to be several dBA lower than that
of the conventional type.
With either muffler, the Evolution .36 ran reliably using suction
fuel feed or muffler pressure. That was with the long, small-bore
venturi. However, the shortest, largest-throat venturi needs muffler
pressure for dependable running in CL maneuvers.
removed the
tank endcap
assembly and
installed a
third tube
through it.
That allowed
me to add a
third short
length of
external
plastic tubing
to use for
refueling.
When the
tank is full, I
pinch the
refill line and insert a short aluminum
roofing nail as a plug.
The three-blade propeller supplied in the
PT-19 package runs smoothly, and the
engine proved to be remarkably easy to
hand-start with it. However, I think a twoblade
propeller with higher pitch is a better
choice for flying a big CL model such as
the PT-19.
That’s because with the medium venturi
installed on the Evolution .36, the threeblade
propeller spins a trifle less than
10,000 rpm. It seems to be nearly 10mm in
pitch—just less than 4 inches. Thus the
highest speed the airplane could attain with
that power-and-propeller combination is
less than 40 mph.
A Graupner 10 x 51/2 propeller and the
Evolution’s biggest-bore venturi would be
preferable for the PT-19. That ought to
result in a flight speed close to 60 mph—or
approximately a 5-second level lap time for
the PT-19 when flown on the provided set
of control lines. I was unable to make that
test.
The profile PT-19 is big (with a 41/2-foot
span and 520 square inches of wing area),
with a thick, round-nosed airfoil, as on my
Veco designs of the 1950s. It also includes
my late, great friend George Aldrich’s
“fixed wing flaps,” as used on his famous
Another unique feature of Evolution
engines is their preset needle valves. These
have “stops” installed that limit the needle
rotation to just less than one full turn.
As on the .46 I tested six months ago, the
factory-supplied needle setting for the .36
turned out to be just right. That is, it was just
right for my altitude, ambient temperature,
and the fuel I used: 15% nitro, 22% lube
content, half castor, half synthetic.
For other environments, such as high
altitudes, it might be necessary to change the
factory setting for the needle. Instructions
for the Evolution .46 describe how to do
that. Similar information ought to be
supplied for the .36, especially since it
performs differently depending on which of
the three venturis is being used.
I found that the PT-19’s fuel tank setup
could be improved. Space between the front
of the plastic “clunk tank” and the Evolution
.36’s rear-mounted needle valve assembly is
limited.
The tank itself comes with a two-tube
outlet arrangement: one tube to the needle
valve nipple and the other to the muffler
pressure tap. That’s okay—until it’s time to
refuel.
There’s too little access space to permit
easily pulling the fuel line off of the needle
nipple to refill the tank. Therefore, I
Flite Streak and Peacemaker CL Aerobatics
models.
The PT-19 is relatively lightweight, at
41 ounces ready to fly. And it’s well built;
nearly all of the parts fit well. Building
instructions are copiously illustrated and
reasonably complete, although they are a bit
ambiguous in a few places. I had little
trouble putting the model together.
However, the PT-19 has three features
that I was dubious about: no rudder offset,
no right thrust, and only 1/2 ounce of tip
weight. I stayed with the first two, but I
used a full ounce of tip weight. My CL
experience shows that it’s better to have too
much than not enough.
When I tested the PT-19’s flying ability,
I was unpleasantly surprised at its minimal
line tension. I was flying in a 5-7 mph wind
and couldn’t backtrack fast enough to keep
the lines taut when the model was on the
upwind side of the circle.
I was flying the PT-19 over concrete.
After its lines slackened and the airplane
dove in, further flying that day became
impossible.
When I repair the PT-19, I’ll follow my
usual practice with CL Aerobatics aircraft
and use several degrees of rudder and
engine offset. I might also add more
outboard tip weight.
In a recent “The Engine Shop” column,
Davis Bolin (Tampa, Florida) saw a photo
of a small metal fuel tank that I had
modified by replacing its brass fuel tubes
with aluminum tubes attached with J.B.
Weld. He uses such tanks in his FF models
(so do I), but his local hobby shop told him
that those are no longer available.
Davis e-mailed me, asking where I
bought my tanks. I informed him that I still
have a bunch of metal tanks that I bought in
the Good Old Days. I also let him know
that Brodak Manufacturing sells almost the
full line of Perfect- and Taff-brand fuel
tanks.
Those are featured on the Brodak Web
site, but they are a little tricky to access.
You need to click on “Fuel” and then
“Fuel Tank.”
On the topic of fuel, Tygon tubing is
unaffected by any kind of model engine
fuel. However, it does tend to stiffen from
exposure to sunlight.
I often use Tygon in my engine work,
but it’s considerably stiffer than silicone.
That makes it unsuitable for use as clunk
tubing. Thinner-walled, more flexible
Tygon tubing became available a few
years ago, yet it kinked easily.
“Doctor Diesel” (Eric Clutton) has
found a source for Tygon tubing that is
both flexible and resistant to kinks. I
bought some—and have found a new use
for it: as replacement tubing in Cox reedvalve
engines such as the Black Widow
and Babe Bee.
The stock tubing in those engines loses
its elasticity from exposure to glow fuel.
That frequently allows air leaks where the
tubing attaches to the needle nipple and
makes reliable running impossible. Eric’s
Tygon tubing is just the thing for solving
that pesky problem. MA
Sources:
Hangar 9
(800) 338-4639
www.hangar-9.com
Brodak Manufacturing
(724) 966-2726
www.brodak.com
Doctor Diesel
(931) 455-2256
www.cafes.net/doctordiesel
82 MODEL AVIATION
Aero Mail
Continued from page 7
Jazzed about Kaz
Just wanted to say thanks for the article on
KAZ [in the August MA]!
I just recently purchased one of these at an
estate sale and wrapped it in trash bags and
Duct tape for a future project, when I get the
chance to get to it.
Duane [Wilson] seems to be a talented
writer so I’m looking forward to seeing his
articles in the future, and NO I’m not a friend
or kin to him! LOL!
I read a lot of the articles because I am an
avid modeler not just an RC guy!
I have a CL model of a Star Wars fighter
hanging in my son’s room a Rubber Powered
P40E model hanging in my room. My RC
collection includes my own designed “Trik
Stik”, 2 Gliders, a T-Rex Helicopter, 2 3-D
planes.
I also have a Rubber powered GeeBee R2
that I’m converting to a CL and a 1910
Valkyrie in the building stage.
John I. Jones
via e-mail
Defensive Praise
Your article on Defensive RC Flying in
the August Model Aviation was absolutely
fantastic. I apply full scale aviation techniques
when building and flying my large scale
aircraft and consequently my oldest one is
now age 27 and still flying great.
You’ve done a terrific service to the
modeling community with this
comprehensive analysis and I am urging all
my club members to read your article.
Conspicuous by its absence though, unless I
missed something which is entirely possible,
was a recommendation to perform a thorough
engine on and off range check when first
completing a model and before the first flight
each and every day.
This is still recommended by radio
equipment manufacturers and I’ve personally
saved at least 3 or 4 airplanes during my time,
and perhaps more importantly physical
injuries to others, by religiously performing
this simple but very important check.
Rich Feroldi
via e-mail
I want to thank you for publishing Don’s
article on Defensive flying. I have been
receiving advice from Don for over a year and
he has shortened my learning curve
drastically. I’ve only been flying for one and a
half years, so his help was greatly appreciated.
The first time that I called Don, it was to
place an order because I’d seen his ad in your
magazine. He did not rush to get me off of the
phone and made sure that I ordered the proper
equipment. I’ve been a loyal customer ever
since.
Mike Watkins
Hobbs, New Mexico
I really appreciated the excellent article
by Don Apostolico. I suspect many an
airplane has been lost for failing to do the
things he has suggested. For those of us who
are not competitors and do these things for a
living, could someone do an article
describing in detail how to set up and use the
suggested test equipment?
This could also include the use of
electrical testing equipment for the new
electric prop, helicopters, and jets. Include
some basic electrical definitions and
explanations about volts, watts, amps, etc.
This might also include the proper use of
voltage regulators, dual switches, power
sources, and which equipment Futaba, JR,
Airtronics, Hitec, etc. requires voltage
regulators.
May be a lot to put in one article, but
would make a great series … keep us
coming back for more. This would also
reach a lot of new pilots, pilots going bigger,
and to electrics in one great place, our AMA
magazine. MA
Terry Webb
via e-mail
Edition: Model Aviation - 2010/10
Page Numbers: 79,80,82
Edition: Model Aviation - 2010/10
Page Numbers: 79,80,82
ONCE IN AWHILE when I receive a new
engine to test and report on to you, it arrives
accompanied by accessories. The Evolution
.36 I recently acquired from Hangar 9 did,
but those “accessories” turned out to be a
complete kit for an ARF CL model—including handle and lines.
The engine itself came with several extras. Two different style
mufflers are provided. One is the conventional sort, with a large
expansion chamber. The other is a much smaller “tongue-type”—so
called (I think) because it resembles a rectangular gray tongue
sticking out of the exhaust port’s “mouth.”
Three venturis come with the Evolution .36. That’s evidently to
make the engine adaptable to a wide range of model sizes. This is a
CL power plant without a throttle. But the venturis are of different
lengths and bore sizes.
By interchanging them, the user can vary the engine’s speed and
power output. The longest venturi has the smallest ID and puts out
the lowest rpm. It was installed on the Evolution .36 I received.
Other Evolution .36 extras were a spinner nut, three-blade
propeller, complete mounting hardware—and all of the various
Allen wrenches needed for engine and airframe assembly.
However, one notable omission in this otherwise complete package
was operation instructions. That struck me as odd, because
Evolution engines have several special features that surely deserve
to be brought to the buyer’s attention. One is that they require no
break-in.
The User Guide booklet for the Evolution .46 RC that I tested
and reported on in this column early this year 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.” My tests on it
verified that.
I installed the engine on my test stand and checked its
performance before and after running six tanks of fuel through it.
Top speed and lowest reliable idle rpm remained essentially the
same throughout.
I did similar bench-testing with the Evolution .36. Out of the box
it hand-started remarkably easily when cold, but it showed some
balkiness when I tried hot restarts. Six tanks of fuel showed no
change in performance.
I tested both mufflers—and was surprised to learn that the tongue
version’s sound output turned out to be several dBA lower than that
of the conventional type.
With either muffler, the Evolution .36 ran reliably using suction
fuel feed or muffler pressure. That was with the long, small-bore
venturi. However, the shortest, largest-throat venturi needs muffler
pressure for dependable running in CL maneuvers.
removed the
tank endcap
assembly and
installed a
third tube
through it.
That allowed
me to add a
third short
length of
external
plastic tubing
to use for
refueling.
When the
tank is full, I
pinch the
refill line and insert a short aluminum
roofing nail as a plug.
The three-blade propeller supplied in the
PT-19 package runs smoothly, and the
engine proved to be remarkably easy to
hand-start with it. However, I think a twoblade
propeller with higher pitch is a better
choice for flying a big CL model such as
the PT-19.
That’s because with the medium venturi
installed on the Evolution .36, the threeblade
propeller spins a trifle less than
10,000 rpm. It seems to be nearly 10mm in
pitch—just less than 4 inches. Thus the
highest speed the airplane could attain with
that power-and-propeller combination is
less than 40 mph.
A Graupner 10 x 51/2 propeller and the
Evolution’s biggest-bore venturi would be
preferable for the PT-19. That ought to
result in a flight speed close to 60 mph—or
approximately a 5-second level lap time for
the PT-19 when flown on the provided set
of control lines. I was unable to make that
test.
The profile PT-19 is big (with a 41/2-foot
span and 520 square inches of wing area),
with a thick, round-nosed airfoil, as on my
Veco designs of the 1950s. It also includes
my late, great friend George Aldrich’s
“fixed wing flaps,” as used on his famous
Another unique feature of Evolution
engines is their preset needle valves. These
have “stops” installed that limit the needle
rotation to just less than one full turn.
As on the .46 I tested six months ago, the
factory-supplied needle setting for the .36
turned out to be just right. That is, it was just
right for my altitude, ambient temperature,
and the fuel I used: 15% nitro, 22% lube
content, half castor, half synthetic.
For other environments, such as high
altitudes, it might be necessary to change the
factory setting for the needle. Instructions
for the Evolution .46 describe how to do
that. Similar information ought to be
supplied for the .36, especially since it
performs differently depending on which of
the three venturis is being used.
I found that the PT-19’s fuel tank setup
could be improved. Space between the front
of the plastic “clunk tank” and the Evolution
.36’s rear-mounted needle valve assembly is
limited.
The tank itself comes with a two-tube
outlet arrangement: one tube to the needle
valve nipple and the other to the muffler
pressure tap. That’s okay—until it’s time to
refuel.
There’s too little access space to permit
easily pulling the fuel line off of the needle
nipple to refill the tank. Therefore, I
Flite Streak and Peacemaker CL Aerobatics
models.
The PT-19 is relatively lightweight, at
41 ounces ready to fly. And it’s well built;
nearly all of the parts fit well. Building
instructions are copiously illustrated and
reasonably complete, although they are a bit
ambiguous in a few places. I had little
trouble putting the model together.
However, the PT-19 has three features
that I was dubious about: no rudder offset,
no right thrust, and only 1/2 ounce of tip
weight. I stayed with the first two, but I
used a full ounce of tip weight. My CL
experience shows that it’s better to have too
much than not enough.
When I tested the PT-19’s flying ability,
I was unpleasantly surprised at its minimal
line tension. I was flying in a 5-7 mph wind
and couldn’t backtrack fast enough to keep
the lines taut when the model was on the
upwind side of the circle.
I was flying the PT-19 over concrete.
After its lines slackened and the airplane
dove in, further flying that day became
impossible.
When I repair the PT-19, I’ll follow my
usual practice with CL Aerobatics aircraft
and use several degrees of rudder and
engine offset. I might also add more
outboard tip weight.
In a recent “The Engine Shop” column,
Davis Bolin (Tampa, Florida) saw a photo
of a small metal fuel tank that I had
modified by replacing its brass fuel tubes
with aluminum tubes attached with J.B.
Weld. He uses such tanks in his FF models
(so do I), but his local hobby shop told him
that those are no longer available.
Davis e-mailed me, asking where I
bought my tanks. I informed him that I still
have a bunch of metal tanks that I bought in
the Good Old Days. I also let him know
that Brodak Manufacturing sells almost the
full line of Perfect- and Taff-brand fuel
tanks.
Those are featured on the Brodak Web
site, but they are a little tricky to access.
You need to click on “Fuel” and then
“Fuel Tank.”
On the topic of fuel, Tygon tubing is
unaffected by any kind of model engine
fuel. However, it does tend to stiffen from
exposure to sunlight.
I often use Tygon in my engine work,
but it’s considerably stiffer than silicone.
That makes it unsuitable for use as clunk
tubing. Thinner-walled, more flexible
Tygon tubing became available a few
years ago, yet it kinked easily.
“Doctor Diesel” (Eric Clutton) has
found a source for Tygon tubing that is
both flexible and resistant to kinks. I
bought some—and have found a new use
for it: as replacement tubing in Cox reedvalve
engines such as the Black Widow
and Babe Bee.
The stock tubing in those engines loses
its elasticity from exposure to glow fuel.
That frequently allows air leaks where the
tubing attaches to the needle nipple and
makes reliable running impossible. Eric’s
Tygon tubing is just the thing for solving
that pesky problem. MA
Sources:
Hangar 9
(800) 338-4639
www.hangar-9.com
Brodak Manufacturing
(724) 966-2726
www.brodak.com
Doctor Diesel
(931) 455-2256
www.cafes.net/doctordiesel
82 MODEL AVIATION
Aero Mail
Continued from page 7
Jazzed about Kaz
Just wanted to say thanks for the article on
KAZ [in the August MA]!
I just recently purchased one of these at an
estate sale and wrapped it in trash bags and
Duct tape for a future project, when I get the
chance to get to it.
Duane [Wilson] seems to be a talented
writer so I’m looking forward to seeing his
articles in the future, and NO I’m not a friend
or kin to him! LOL!
I read a lot of the articles because I am an
avid modeler not just an RC guy!
I have a CL model of a Star Wars fighter
hanging in my son’s room a Rubber Powered
P40E model hanging in my room. My RC
collection includes my own designed “Trik
Stik”, 2 Gliders, a T-Rex Helicopter, 2 3-D
planes.
I also have a Rubber powered GeeBee R2
that I’m converting to a CL and a 1910
Valkyrie in the building stage.
John I. Jones
via e-mail
Defensive Praise
Your article on Defensive RC Flying in
the August Model Aviation was absolutely
fantastic. I apply full scale aviation techniques
when building and flying my large scale
aircraft and consequently my oldest one is
now age 27 and still flying great.
You’ve done a terrific service to the
modeling community with this
comprehensive analysis and I am urging all
my club members to read your article.
Conspicuous by its absence though, unless I
missed something which is entirely possible,
was a recommendation to perform a thorough
engine on and off range check when first
completing a model and before the first flight
each and every day.
This is still recommended by radio
equipment manufacturers and I’ve personally
saved at least 3 or 4 airplanes during my time,
and perhaps more importantly physical
injuries to others, by religiously performing
this simple but very important check.
Rich Feroldi
via e-mail
I want to thank you for publishing Don’s
article on Defensive flying. I have been
receiving advice from Don for over a year and
he has shortened my learning curve
drastically. I’ve only been flying for one and a
half years, so his help was greatly appreciated.
The first time that I called Don, it was to
place an order because I’d seen his ad in your
magazine. He did not rush to get me off of the
phone and made sure that I ordered the proper
equipment. I’ve been a loyal customer ever
since.
Mike Watkins
Hobbs, New Mexico
I really appreciated the excellent article
by Don Apostolico. I suspect many an
airplane has been lost for failing to do the
things he has suggested. For those of us who
are not competitors and do these things for a
living, could someone do an article
describing in detail how to set up and use the
suggested test equipment?
This could also include the use of
electrical testing equipment for the new
electric prop, helicopters, and jets. Include
some basic electrical definitions and
explanations about volts, watts, amps, etc.
This might also include the proper use of
voltage regulators, dual switches, power
sources, and which equipment Futaba, JR,
Airtronics, Hitec, etc. requires voltage
regulators.
May be a lot to put in one article, but
would make a great series … keep us
coming back for more. This would also
reach a lot of new pilots, pilots going bigger,
and to electrics in one great place, our AMA
magazine. MA
Terry Webb
via e-mail
Edition: Model Aviation - 2010/10
Page Numbers: 79,80,82
ONCE IN AWHILE when I receive a new
engine to test and report on to you, it arrives
accompanied by accessories. The Evolution
.36 I recently acquired from Hangar 9 did,
but those “accessories” turned out to be a
complete kit for an ARF CL model—including handle and lines.
The engine itself came with several extras. Two different style
mufflers are provided. One is the conventional sort, with a large
expansion chamber. The other is a much smaller “tongue-type”—so
called (I think) because it resembles a rectangular gray tongue
sticking out of the exhaust port’s “mouth.”
Three venturis come with the Evolution .36. That’s evidently to
make the engine adaptable to a wide range of model sizes. This is a
CL power plant without a throttle. But the venturis are of different
lengths and bore sizes.
By interchanging them, the user can vary the engine’s speed and
power output. The longest venturi has the smallest ID and puts out
the lowest rpm. It was installed on the Evolution .36 I received.
Other Evolution .36 extras were a spinner nut, three-blade
propeller, complete mounting hardware—and all of the various
Allen wrenches needed for engine and airframe assembly.
However, one notable omission in this otherwise complete package
was operation instructions. That struck me as odd, because
Evolution engines have several special features that surely deserve
to be brought to the buyer’s attention. One is that they require no
break-in.
The User Guide booklet for the Evolution .46 RC that I tested
and reported on in this column early this year 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.” My tests on it
verified that.
I installed the engine on my test stand and checked its
performance before and after running six tanks of fuel through it.
Top speed and lowest reliable idle rpm remained essentially the
same throughout.
I did similar bench-testing with the Evolution .36. Out of the box
it hand-started remarkably easily when cold, but it showed some
balkiness when I tried hot restarts. Six tanks of fuel showed no
change in performance.
I tested both mufflers—and was surprised to learn that the tongue
version’s sound output turned out to be several dBA lower than that
of the conventional type.
With either muffler, the Evolution .36 ran reliably using suction
fuel feed or muffler pressure. That was with the long, small-bore
venturi. However, the shortest, largest-throat venturi needs muffler
pressure for dependable running in CL maneuvers.
removed the
tank endcap
assembly and
installed a
third tube
through it.
That allowed
me to add a
third short
length of
external
plastic tubing
to use for
refueling.
When the
tank is full, I
pinch the
refill line and insert a short aluminum
roofing nail as a plug.
The three-blade propeller supplied in the
PT-19 package runs smoothly, and the
engine proved to be remarkably easy to
hand-start with it. However, I think a twoblade
propeller with higher pitch is a better
choice for flying a big CL model such as
the PT-19.
That’s because with the medium venturi
installed on the Evolution .36, the threeblade
propeller spins a trifle less than
10,000 rpm. It seems to be nearly 10mm in
pitch—just less than 4 inches. Thus the
highest speed the airplane could attain with
that power-and-propeller combination is
less than 40 mph.
A Graupner 10 x 51/2 propeller and the
Evolution’s biggest-bore venturi would be
preferable for the PT-19. That ought to
result in a flight speed close to 60 mph—or
approximately a 5-second level lap time for
the PT-19 when flown on the provided set
of control lines. I was unable to make that
test.
The profile PT-19 is big (with a 41/2-foot
span and 520 square inches of wing area),
with a thick, round-nosed airfoil, as on my
Veco designs of the 1950s. It also includes
my late, great friend George Aldrich’s
“fixed wing flaps,” as used on his famous
Another unique feature of Evolution
engines is their preset needle valves. These
have “stops” installed that limit the needle
rotation to just less than one full turn.
As on the .46 I tested six months ago, the
factory-supplied needle setting for the .36
turned out to be just right. That is, it was just
right for my altitude, ambient temperature,
and the fuel I used: 15% nitro, 22% lube
content, half castor, half synthetic.
For other environments, such as high
altitudes, it might be necessary to change the
factory setting for the needle. Instructions
for the Evolution .46 describe how to do
that. Similar information ought to be
supplied for the .36, especially since it
performs differently depending on which of
the three venturis is being used.
I found that the PT-19’s fuel tank setup
could be improved. Space between the front
of the plastic “clunk tank” and the Evolution
.36’s rear-mounted needle valve assembly is
limited.
The tank itself comes with a two-tube
outlet arrangement: one tube to the needle
valve nipple and the other to the muffler
pressure tap. That’s okay—until it’s time to
refuel.
There’s too little access space to permit
easily pulling the fuel line off of the needle
nipple to refill the tank. Therefore, I
Flite Streak and Peacemaker CL Aerobatics
models.
The PT-19 is relatively lightweight, at
41 ounces ready to fly. And it’s well built;
nearly all of the parts fit well. Building
instructions are copiously illustrated and
reasonably complete, although they are a bit
ambiguous in a few places. I had little
trouble putting the model together.
However, the PT-19 has three features
that I was dubious about: no rudder offset,
no right thrust, and only 1/2 ounce of tip
weight. I stayed with the first two, but I
used a full ounce of tip weight. My CL
experience shows that it’s better to have too
much than not enough.
When I tested the PT-19’s flying ability,
I was unpleasantly surprised at its minimal
line tension. I was flying in a 5-7 mph wind
and couldn’t backtrack fast enough to keep
the lines taut when the model was on the
upwind side of the circle.
I was flying the PT-19 over concrete.
After its lines slackened and the airplane
dove in, further flying that day became
impossible.
When I repair the PT-19, I’ll follow my
usual practice with CL Aerobatics aircraft
and use several degrees of rudder and
engine offset. I might also add more
outboard tip weight.
In a recent “The Engine Shop” column,
Davis Bolin (Tampa, Florida) saw a photo
of a small metal fuel tank that I had
modified by replacing its brass fuel tubes
with aluminum tubes attached with J.B.
Weld. He uses such tanks in his FF models
(so do I), but his local hobby shop told him
that those are no longer available.
Davis e-mailed me, asking where I
bought my tanks. I informed him that I still
have a bunch of metal tanks that I bought in
the Good Old Days. I also let him know
that Brodak Manufacturing sells almost the
full line of Perfect- and Taff-brand fuel
tanks.
Those are featured on the Brodak Web
site, but they are a little tricky to access.
You need to click on “Fuel” and then
“Fuel Tank.”
On the topic of fuel, Tygon tubing is
unaffected by any kind of model engine
fuel. However, it does tend to stiffen from
exposure to sunlight.
I often use Tygon in my engine work,
but it’s considerably stiffer than silicone.
That makes it unsuitable for use as clunk
tubing. Thinner-walled, more flexible
Tygon tubing became available a few
years ago, yet it kinked easily.
“Doctor Diesel” (Eric Clutton) has
found a source for Tygon tubing that is
both flexible and resistant to kinks. I
bought some—and have found a new use
for it: as replacement tubing in Cox reedvalve
engines such as the Black Widow
and Babe Bee.
The stock tubing in those engines loses
its elasticity from exposure to glow fuel.
That frequently allows air leaks where the
tubing attaches to the needle nipple and
makes reliable running impossible. Eric’s
Tygon tubing is just the thing for solving
that pesky problem. MA
Sources:
Hangar 9
(800) 338-4639
www.hangar-9.com
Brodak Manufacturing
(724) 966-2726
www.brodak.com
Doctor Diesel
(931) 455-2256
www.cafes.net/doctordiesel
82 MODEL AVIATION
Aero Mail
Continued from page 7
Jazzed about Kaz
Just wanted to say thanks for the article on
KAZ [in the August MA]!
I just recently purchased one of these at an
estate sale and wrapped it in trash bags and
Duct tape for a future project, when I get the
chance to get to it.
Duane [Wilson] seems to be a talented
writer so I’m looking forward to seeing his
articles in the future, and NO I’m not a friend
or kin to him! LOL!
I read a lot of the articles because I am an
avid modeler not just an RC guy!
I have a CL model of a Star Wars fighter
hanging in my son’s room a Rubber Powered
P40E model hanging in my room. My RC
collection includes my own designed “Trik
Stik”, 2 Gliders, a T-Rex Helicopter, 2 3-D
planes.
I also have a Rubber powered GeeBee R2
that I’m converting to a CL and a 1910
Valkyrie in the building stage.
John I. Jones
via e-mail
Defensive Praise
Your article on Defensive RC Flying in
the August Model Aviation was absolutely
fantastic. I apply full scale aviation techniques
when building and flying my large scale
aircraft and consequently my oldest one is
now age 27 and still flying great.
You’ve done a terrific service to the
modeling community with this
comprehensive analysis and I am urging all
my club members to read your article.
Conspicuous by its absence though, unless I
missed something which is entirely possible,
was a recommendation to perform a thorough
engine on and off range check when first
completing a model and before the first flight
each and every day.
This is still recommended by radio
equipment manufacturers and I’ve personally
saved at least 3 or 4 airplanes during my time,
and perhaps more importantly physical
injuries to others, by religiously performing
this simple but very important check.
Rich Feroldi
via e-mail
I want to thank you for publishing Don’s
article on Defensive flying. I have been
receiving advice from Don for over a year and
he has shortened my learning curve
drastically. I’ve only been flying for one and a
half years, so his help was greatly appreciated.
The first time that I called Don, it was to
place an order because I’d seen his ad in your
magazine. He did not rush to get me off of the
phone and made sure that I ordered the proper
equipment. I’ve been a loyal customer ever
since.
Mike Watkins
Hobbs, New Mexico
I really appreciated the excellent article
by Don Apostolico. I suspect many an
airplane has been lost for failing to do the
things he has suggested. For those of us who
are not competitors and do these things for a
living, could someone do an article
describing in detail how to set up and use the
suggested test equipment?
This could also include the use of
electrical testing equipment for the new
electric prop, helicopters, and jets. Include
some basic electrical definitions and
explanations about volts, watts, amps, etc.
This might also include the proper use of
voltage regulators, dual switches, power
sources, and which equipment Futaba, JR,
Airtronics, Hitec, etc. requires voltage
regulators.
May be a lot to put in one article, but
would make a great series … keep us
coming back for more. This would also
reach a lot of new pilots, pilots going bigger,
and to electrics in one great place, our AMA
magazine. MA
Terry Webb
via e-mail
