AH, THE GOLDEN Age of Aviation:
the years between World War I and World
War II. There is no other era in which
aircraft design was so elegant,
sophisticated, and simply stunning. The
names roll off of any enthusiasts’ tongues;
they include Beechcraft, Curtiss,
Monocoupe, Travel Air, Aeronca, Cessna,
and so on.
However, when it comes to biplanes
that list of names shrinks substantially.
And a small firm in Troy, Ohio (the Waco
Aircraft Company), designed and
manufactured a beautiful biplane named
the YMF-5.
The review kit is based on a YMF-5D
that the WACO Classic Aircraft
Corporation (Battle Creek, Michigan) is
currently manufacturing. With a wingspan
of 72 inches, this model comes in at
exactly 1/5 scale.
First Impressions: It had been quite a
while since I had the chance to review one
of Great Planes’ big scale ARFs, and I
was looking forward to this one—not only
MonoKote or painted a matching yellow.
The color scheme also included black
trim with red pinstriping. Some of it was
MonoKote, some was painted, and some
was decals.
There are numerous seams, especially on
the fuselage, but nothing to be alarmed
about. After going over all pieces with an
iron to “de-wrinkle,” the only real surprise
was where the covering wrapped around the
lower wing saddle and firewall; it was
trimmed very close to the edge.
Ninety-five percent of the airframe
construction was balsa and plywood. It was
clear that the Great Planes team put a lot of
thought into this model design. There were
also many laser-cut pieces.
Then there was the hardware: items
you’d expect in an ARF, such as clevises,
pushrods, and an engine mount. And there
were other niceties, including foam wheels,
airfoil-shaped wing and cabane struts, a fuel
tank with a double-clunk system, laser-cut
pieces for proper engine spacing, Americansized
screws/nuts, and more. A wealth of
fiberglass parts was included as well.
because of the subject, but to see how these
models had progressed in design and
techniques. I thought it should be a fun
project!
After opening all the packaging, I found
that Great Planes had not only furnished
the kit, but an engine and flight pack to go
with it. The power plant isn’t what would
have been my first choice because it was a
two-stroke.
I would normally choose a four-stroke
for power, but we’ll see how this goes.
Besides, the Great Planes also included a
Bisson Pitts muffler for the size of mount.
When I opened the kit, I saw that
everything was bagged and sectioned off to
protect it from the rigors of shipping. Then
there’s the tape—miles of clear packing
tape holding everything in position. I’ll bet
I spent a good 15 minutes carefully
removing tape from the bags and
packaging!
When I examined the pieces, I was
quickly overcome by a wave of yellow.
There were many parts in this kit, and all
were either covered in yellow Top Flite
The cowl (with blisters) and wheel pants
came with all trim applied. There was a set
of wing fillets and a large, round cover that
could be used to cover the passenger
compartment. The landing gear was not
merely prepainted; it also had the fiberglass
fairing attached and painted in one seamless
piece.
In addition, there was a bag of wooden
pieces—lots of them. A few were obvious—
they were radio trays, etc.—but I was
puzzled about the others. Looking through
the manual, I saw that these parts were
engine-mount spacers and pieces for a
handle that attaches to the cabane struts.
Last but not least was the manual. It
contained 40 pages of highly detailed
information and each step accompanied by
great photography to take away the
guesswork. If you’d like to see how this
project looks before you purchase it, the
manual is available on the Great Planes
website.
This was excellent stuff! Let’s get
started.
Oh, before I go further, this is not a
beginner’s airplane. If you are a newer
builder or pilot, you shouldn’t consider it
for even a second or third model. Great
Planes has done a great job of bringing this
complex design to a simpler level, but you
should take on the YMF-5D ARF only if
you are an intermediate to experienced
modeler.
Assembly: As with all ARF reviews, I
won’t quote the manual step by step.
Instead I’ll gently go over the build and
focus on steps for which a bit more
attention is needed. Let’s start with the
wings.
The ailerons are attached to wooden
blocks, which are then attached to the servo
covers. Pushrods, clevises, and control
horns are installed on each of the four
ailerons. All wires are pulled through the
wing panels using preinstalled strings.
The top wing has small angle brackets
installed, and then the panels are glued
together (two panels for the bottom and
three for the top). Each panel has a set of
dihedral braces that you need to build.
The LE braces have two light-plywood
parts sandwiching an aluminum center
brace. Together they make an incredibly
strong piece. The rear braces are lightplywood
pieces glued together.
Before mixing the epoxy to assemble
each wing, take some extra time to file and
sand the braces so they fit. Originally they
wouldn’t push into the wing slots at all, and
it took a lot of elbow grease to shape them
so they would slide in snugly.
Then assembly moves on to the
fuselage. The landing gear is first, and it’s
extremely straightforward because of all the
work done at the factory.
There is a built-up cover that is glued
into place after the landing gear is attached.
This cover had two small balsa pieces taped
to the bottom; they appeared to be padding
for shipping. Be sure to remove them first.
The manual doesn’t mention this.
The only other thing to note on the gear
is that you’ll have to trim 1/4 inch off of
each main gear axle. That’s easy to do with
a rotary tool and cutoff wheel.
Remember all those extra wood pieces I
mentioned earlier? Here’s where we get to
learn their purpose.
In a few steps those laser-cut plywood
parts are doubled up, and before you know
it you have a cool handle that mounts to the
cabane struts. This handle is perfect for
securely holding and moving the fuselage
with one hand.
Even after everything is in (radio,
engine, etc.), the handle is in the perfect
spot: directly on the CG. It also works well
when you have to flip the fuselage upsidedown
for the other steps; it makes a nice,
flat surface.
Now work switches to the tail, where
the stabilizer halves are installed using a
couple of aluminum tubes that slide into the
fuselage and align everything nicely. Then
the tail wheel is installed.
Note that you will have to enlarge the
cutout in the bottom of the rudder quite a
bit to clear the tail wheel mounts. Once
the cutout is correct, the rudder is
attached using three CA-type hinges.
Rudder and elevator servos, pushrods,
clevises, and control horns are installed
next. There are no surprises here, and all
included hardware works well.
On to the engine. The manual covers
installation of a four-stroke glow and twostroke
gasoline power plant in detail.
However, the O.S. 95 AX two-stroke glow
engine supplied with the review model isn’t
covered at all.
To install the 95 AX, follow the fourstroke
instructions for the first three steps.
The fourth step (wood engine spacers) is
where things change a bit.
Mount the O.S. to the mount. Although
it needs to be installed far forward, the
engine mount has a sharply angled portion
at the front of each mounting beam. Do not
use this area because the mount thins
significantly. I mounted the engine
approximately 1/8 inch aft of this angle.
Then I found that there was not enough
of either wooden mount spacers to get the
correct firewall-to-drive washer distance of
611/16 inches. So, as you can see in the
photo, I combined the two. The rounded
spacers had to be cut as shown, so that the
mounting holes would line up correctly.
When finished I used all six square spacers
and an additional four modified rounded
spacers.
Your measurements might be different,
but heed the 611/16 inches; that is the
minimum distance. A little longer is okay,
but do not shorten this distance.
And be sure that the muffler you use
will clear the firewall. The supplied Bisson
Pitts fit perfectly.
Once you have the proper distance, glue
all the pieces together and fuel-proof them
by either using thinned 30-minute epoxy or
spraying on a coat of clear fuelproof paint.
Now you can return to the manual at the
eighth step of engine installation and finish
bolting the mount to the model, hooking up
the throttle linkage and installing the
throttle servo.
If you go with the two-stroke option, the
throttle pushrod will likely need to be
drilled in a different location than is shown
in the manual.
If you choose to power the YMF-5Dwith a gas engine, the WACO package
includes a few other laser-cut pieces to use
to build an ignition and battery tray that
mounts to the front of the firewall, directly
above the engine. Also included is a
different plastic pushrod to keep ignition
noise away from the radio system. These are
very nice touches.
Most ARFs these days include a fuel
tank, but this is the first I’ve seen that also
includes a double-clunk system. I’ve always
preferred this system, to make it easier to
fill and empty the tank.
The tank is held in the fuselage with a
rubber band. The manual shows how to
install it using a hook, but that didn’t work
for me. Luckily my wife’s hands were the
right size to reach into the small space and
put things right!
The next step is installing the cowl. To
do this, you first need to assemble the pieces
of the cowl centering tool. I had to sand the
cowl opening considerably to allow the ring
to fit. (It’s better to take the weight off of
the model than the tool.)
Once I attained a good fit, I made the
cutout for muffler clearance and engine
cooling.
Mounting the cowl to the fuselage is
designed to be a discreet operation, with
nothing visible from the outside (as on the
full-scale WACO). Two laser-cut lightplywood
rings are included; one bolts to the
fuselage and the other is glued to the inside
of the cowl.
However, it is a challenge to get the
adhesive inside the cowl, with the front
opening complete covered by the centering
tool. The manual simply advises you to
brush on 30-minute epoxy (with fiberglass
filler) and shove on the cowl. This seemed a
bit messy, so I took a slightly different
approach.
I modified the centering tool by cutting
out three large sections so I could carefully
apply the epoxy with a long paintbrush. It
worked like a charm.
The cowl doesn’t have to be epoxied all
the way around—just enough to hold it in
place so it can be carefully removed. Then
you can easily get to the inside and do a
proper job with the epoxy.
The rest of the radio system is a breeze
to install. A large wing-saddle opening
allows even my large hands to get to
everything. Great Planes also includes a
variety of light-plywood templates to make
easy work of cutting holes for the external
switch and charging jack.
I didn’t want to cut a hole in the cowl
through which to stick the glow-plug
igniter. While looking around at options I
contacted Sonic-Tronics to get an opinion
on what I should do.
The company has both a remote Ni-
Starter, which moves the glow plug
connection to a different point (say the
cockpit), and an onboard system, which
Sonic-Tronics thought was the better choice.
That system is normally used on four-stoke
engines to keep the plug hot, but it also
allows you to have onboard “heat” to start
the engine with no external wires.
This system is the Super Mcd466
onboard glow driver: a small, self-contained
driver that has everything you need,
including a charger. The little box works in
parallel with the throttle servo (via a Yharness)
and has a rotary adjustment to
determine the on/off point.
I set up the drive to be on at 0%-25%
throttle and off at more than that. A great
safety feature of the Mcd466 is that when
you turn off the radio, the power to the plug
is off as well.
Finishing assembly are the wheel pants,
which are a breeze to install, and a number
of other parts that you adhere using RC-56
(or equivalent) white glue.
To go a bit further, you can detail the
included dummy engine, make the model a
one-seater by gluing on the included
forward cockpit cover, or make the
instrument panels and install them for both
cockpits. I would have liked it if Great
Planes had included a pilot as well, but it
didn’t so I picked one up at my local hobby
shop.
Bolting everything together for the first
time took close to 10 minutes. The bottom
wing attaches to the fuselage with two nylon
bolts. The upper wing and struts attach with
4-40 screws, washers, and locknuts. Be sure
to have extra of those on hand; they’re sure
to disappear at the field.
All finished, the review YMF-5D came
in at 12.5 pounds ready to fly. That
which is good. And, surprisingly, the CG
was spot on. I was expecting to have to
move things slightly forward.
Flying: Before I took the WACO out to the
field, I watched Great Planes’ online
videos—specifically paying attention to the
speed at which the models were flying. It
worried me that the flying was a tad faster
than with a “scale” look. So for the first
flight I decided to keep the speed up a bit
until I was comfortable with the airplane.
While throttling up on the takeoff roll, it
became apparent that this aircraft was
overpowered to say the least. After a 40- to
50-foot roll, it climbed resembling a Pylon
racer rather than a barnstormer.
After a few trim passes and photo passes
were out of the way, I decided to wring out
the model at full throttle. Holy Toledo!
There was a lot of power there, and the
airframe was more than up to the task.
Huge loops, Cuban eights, and
Immelmann turns were in the YMF-5’s
repertoire at this power level. There wasn’t
enough power to hover, but I don’t think
you’d have much trouble practicing most
novice and advanced RC Aerobatics
maneuvers with this setup.
After tearing up the sky, it was time for
the first landing. Throttling down, the
WACO came in a little hot and completely
overshot the runway. It turns out that even
with all that extra drag, this model was a
floater and didn’t slow as quickly as I
thought it might.
But after a few attempts to figure it out, I
found myself throttling to idle immediately
after turning on the downwind portion of
the landing pattern. The base and final legs
of the pattern were much more manageable
then.
With the next flights, it was time to fly
the YMF-5D as it should be flown: slowly
and gracefully. With the O.S. 95 AX, it
needed only one-third throttle to fly in a
scalelike fashion.
I bumped up the throttle to half for
rolls and loops. At that setting the model
would do anything you might have seen the
full-scale aircraft do, and do well.
Wow, what a great-looking model. As I
mentioned at the start, it had been awhile
since my last Great Planes scale ARF
review—they have come a long way.
So much is done for you at the factory
now. But more than that, numerous
templates and tools are included to make
the work straight, true, and effortless.
Since the first flights I’ve piloted this
ARF many times and am having a ball with
it. It’s a true barnstormer, and Great Planes
has done a fine job with the design.
Experimenting with the flight envelope,
I’ve found that when the model is trimmed
for scale flight (one-third to half throttle),
going to full throttle causes it to climb
rapidly; you and your elevator trim will
become fast friends. But on the low end this
airplane has no tendency to tip stall or do
anything alarming.
Takeoffs need a lot of right rudder to
keep the aircraft pointed down the runway.
Landings are a bit bouncy using the
included foam wheels; I’ll probably switch
those to a softer foam or rubber.
The Sonic-Tronics onboard glow system
has been a great addition and makes starting
the 95 AX a breeze. I installed the indicator
light in the floor of the front cockpit so I
can easily see when the driver is powered
during startup. I’m not sure how long its
onboard battery will last, but I’ve made as
many as eight flights in a day and it still has
power.
Although this YMF-5D is a great
candidate for AMA Fun Scale competition,
the fact that it comes with registration
numbers that couldn’t be found on any fullscale
WACO presents a problem. But after
a bit of research I found a photo that should
do the trick. It’s online, and you can
download it at the website address listed in
the “Sources.” MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
Great Planes Model Manufacturing
Box 9021
Champaign IL 61826
(217) 398-8970
www.greatplanes.com
Sources:
Sonic-Tronics
(888) 721-0128
www.sonictronics.com
1-inch A-style propeller hub:
Tru-Turn
(218) 479-9600
www.tru-turn.com
Master Aircrew
www.masterairscrew.com
WACO photo (courtesy WACO Classic
Aircraft Corporation):
http://bit.ly/gu0hAv
Edition: Model Aviation - 2011/07
Page Numbers: 50,51,52,53,55,57,59
Edition: Model Aviation - 2011/07
Page Numbers: 50,51,52,53,55,57,59
AH, THE GOLDEN Age of Aviation:
the years between World War I and World
War II. There is no other era in which
aircraft design was so elegant,
sophisticated, and simply stunning. The
names roll off of any enthusiasts’ tongues;
they include Beechcraft, Curtiss,
Monocoupe, Travel Air, Aeronca, Cessna,
and so on.
However, when it comes to biplanes
that list of names shrinks substantially.
And a small firm in Troy, Ohio (the Waco
Aircraft Company), designed and
manufactured a beautiful biplane named
the YMF-5.
The review kit is based on a YMF-5D
that the WACO Classic Aircraft
Corporation (Battle Creek, Michigan) is
currently manufacturing. With a wingspan
of 72 inches, this model comes in at
exactly 1/5 scale.
First Impressions: It had been quite a
while since I had the chance to review one
of Great Planes’ big scale ARFs, and I
was looking forward to this one—not only
MonoKote or painted a matching yellow.
The color scheme also included black
trim with red pinstriping. Some of it was
MonoKote, some was painted, and some
was decals.
There are numerous seams, especially on
the fuselage, but nothing to be alarmed
about. After going over all pieces with an
iron to “de-wrinkle,” the only real surprise
was where the covering wrapped around the
lower wing saddle and firewall; it was
trimmed very close to the edge.
Ninety-five percent of the airframe
construction was balsa and plywood. It was
clear that the Great Planes team put a lot of
thought into this model design. There were
also many laser-cut pieces.
Then there was the hardware: items
you’d expect in an ARF, such as clevises,
pushrods, and an engine mount. And there
were other niceties, including foam wheels,
airfoil-shaped wing and cabane struts, a fuel
tank with a double-clunk system, laser-cut
pieces for proper engine spacing, Americansized
screws/nuts, and more. A wealth of
fiberglass parts was included as well.
because of the subject, but to see how these
models had progressed in design and
techniques. I thought it should be a fun
project!
After opening all the packaging, I found
that Great Planes had not only furnished
the kit, but an engine and flight pack to go
with it. The power plant isn’t what would
have been my first choice because it was a
two-stroke.
I would normally choose a four-stroke
for power, but we’ll see how this goes.
Besides, the Great Planes also included a
Bisson Pitts muffler for the size of mount.
When I opened the kit, I saw that
everything was bagged and sectioned off to
protect it from the rigors of shipping. Then
there’s the tape—miles of clear packing
tape holding everything in position. I’ll bet
I spent a good 15 minutes carefully
removing tape from the bags and
packaging!
When I examined the pieces, I was
quickly overcome by a wave of yellow.
There were many parts in this kit, and all
were either covered in yellow Top Flite
The cowl (with blisters) and wheel pants
came with all trim applied. There was a set
of wing fillets and a large, round cover that
could be used to cover the passenger
compartment. The landing gear was not
merely prepainted; it also had the fiberglass
fairing attached and painted in one seamless
piece.
In addition, there was a bag of wooden
pieces—lots of them. A few were obvious—
they were radio trays, etc.—but I was
puzzled about the others. Looking through
the manual, I saw that these parts were
engine-mount spacers and pieces for a
handle that attaches to the cabane struts.
Last but not least was the manual. It
contained 40 pages of highly detailed
information and each step accompanied by
great photography to take away the
guesswork. If you’d like to see how this
project looks before you purchase it, the
manual is available on the Great Planes
website.
This was excellent stuff! Let’s get
started.
Oh, before I go further, this is not a
beginner’s airplane. If you are a newer
builder or pilot, you shouldn’t consider it
for even a second or third model. Great
Planes has done a great job of bringing this
complex design to a simpler level, but you
should take on the YMF-5D ARF only if
you are an intermediate to experienced
modeler.
Assembly: As with all ARF reviews, I
won’t quote the manual step by step.
Instead I’ll gently go over the build and
focus on steps for which a bit more
attention is needed. Let’s start with the
wings.
The ailerons are attached to wooden
blocks, which are then attached to the servo
covers. Pushrods, clevises, and control
horns are installed on each of the four
ailerons. All wires are pulled through the
wing panels using preinstalled strings.
The top wing has small angle brackets
installed, and then the panels are glued
together (two panels for the bottom and
three for the top). Each panel has a set of
dihedral braces that you need to build.
The LE braces have two light-plywood
parts sandwiching an aluminum center
brace. Together they make an incredibly
strong piece. The rear braces are lightplywood
pieces glued together.
Before mixing the epoxy to assemble
each wing, take some extra time to file and
sand the braces so they fit. Originally they
wouldn’t push into the wing slots at all, and
it took a lot of elbow grease to shape them
so they would slide in snugly.
Then assembly moves on to the
fuselage. The landing gear is first, and it’s
extremely straightforward because of all the
work done at the factory.
There is a built-up cover that is glued
into place after the landing gear is attached.
This cover had two small balsa pieces taped
to the bottom; they appeared to be padding
for shipping. Be sure to remove them first.
The manual doesn’t mention this.
The only other thing to note on the gear
is that you’ll have to trim 1/4 inch off of
each main gear axle. That’s easy to do with
a rotary tool and cutoff wheel.
Remember all those extra wood pieces I
mentioned earlier? Here’s where we get to
learn their purpose.
In a few steps those laser-cut plywood
parts are doubled up, and before you know
it you have a cool handle that mounts to the
cabane struts. This handle is perfect for
securely holding and moving the fuselage
with one hand.
Even after everything is in (radio,
engine, etc.), the handle is in the perfect
spot: directly on the CG. It also works well
when you have to flip the fuselage upsidedown
for the other steps; it makes a nice,
flat surface.
Now work switches to the tail, where
the stabilizer halves are installed using a
couple of aluminum tubes that slide into the
fuselage and align everything nicely. Then
the tail wheel is installed.
Note that you will have to enlarge the
cutout in the bottom of the rudder quite a
bit to clear the tail wheel mounts. Once
the cutout is correct, the rudder is
attached using three CA-type hinges.
Rudder and elevator servos, pushrods,
clevises, and control horns are installed
next. There are no surprises here, and all
included hardware works well.
On to the engine. The manual covers
installation of a four-stroke glow and twostroke
gasoline power plant in detail.
However, the O.S. 95 AX two-stroke glow
engine supplied with the review model isn’t
covered at all.
To install the 95 AX, follow the fourstroke
instructions for the first three steps.
The fourth step (wood engine spacers) is
where things change a bit.
Mount the O.S. to the mount. Although
it needs to be installed far forward, the
engine mount has a sharply angled portion
at the front of each mounting beam. Do not
use this area because the mount thins
significantly. I mounted the engine
approximately 1/8 inch aft of this angle.
Then I found that there was not enough
of either wooden mount spacers to get the
correct firewall-to-drive washer distance of
611/16 inches. So, as you can see in the
photo, I combined the two. The rounded
spacers had to be cut as shown, so that the
mounting holes would line up correctly.
When finished I used all six square spacers
and an additional four modified rounded
spacers.
Your measurements might be different,
but heed the 611/16 inches; that is the
minimum distance. A little longer is okay,
but do not shorten this distance.
And be sure that the muffler you use
will clear the firewall. The supplied Bisson
Pitts fit perfectly.
Once you have the proper distance, glue
all the pieces together and fuel-proof them
by either using thinned 30-minute epoxy or
spraying on a coat of clear fuelproof paint.
Now you can return to the manual at the
eighth step of engine installation and finish
bolting the mount to the model, hooking up
the throttle linkage and installing the
throttle servo.
If you go with the two-stroke option, the
throttle pushrod will likely need to be
drilled in a different location than is shown
in the manual.
If you choose to power the YMF-5Dwith a gas engine, the WACO package
includes a few other laser-cut pieces to use
to build an ignition and battery tray that
mounts to the front of the firewall, directly
above the engine. Also included is a
different plastic pushrod to keep ignition
noise away from the radio system. These are
very nice touches.
Most ARFs these days include a fuel
tank, but this is the first I’ve seen that also
includes a double-clunk system. I’ve always
preferred this system, to make it easier to
fill and empty the tank.
The tank is held in the fuselage with a
rubber band. The manual shows how to
install it using a hook, but that didn’t work
for me. Luckily my wife’s hands were the
right size to reach into the small space and
put things right!
The next step is installing the cowl. To
do this, you first need to assemble the pieces
of the cowl centering tool. I had to sand the
cowl opening considerably to allow the ring
to fit. (It’s better to take the weight off of
the model than the tool.)
Once I attained a good fit, I made the
cutout for muffler clearance and engine
cooling.
Mounting the cowl to the fuselage is
designed to be a discreet operation, with
nothing visible from the outside (as on the
full-scale WACO). Two laser-cut lightplywood
rings are included; one bolts to the
fuselage and the other is glued to the inside
of the cowl.
However, it is a challenge to get the
adhesive inside the cowl, with the front
opening complete covered by the centering
tool. The manual simply advises you to
brush on 30-minute epoxy (with fiberglass
filler) and shove on the cowl. This seemed a
bit messy, so I took a slightly different
approach.
I modified the centering tool by cutting
out three large sections so I could carefully
apply the epoxy with a long paintbrush. It
worked like a charm.
The cowl doesn’t have to be epoxied all
the way around—just enough to hold it in
place so it can be carefully removed. Then
you can easily get to the inside and do a
proper job with the epoxy.
The rest of the radio system is a breeze
to install. A large wing-saddle opening
allows even my large hands to get to
everything. Great Planes also includes a
variety of light-plywood templates to make
easy work of cutting holes for the external
switch and charging jack.
I didn’t want to cut a hole in the cowl
through which to stick the glow-plug
igniter. While looking around at options I
contacted Sonic-Tronics to get an opinion
on what I should do.
The company has both a remote Ni-
Starter, which moves the glow plug
connection to a different point (say the
cockpit), and an onboard system, which
Sonic-Tronics thought was the better choice.
That system is normally used on four-stoke
engines to keep the plug hot, but it also
allows you to have onboard “heat” to start
the engine with no external wires.
This system is the Super Mcd466
onboard glow driver: a small, self-contained
driver that has everything you need,
including a charger. The little box works in
parallel with the throttle servo (via a Yharness)
and has a rotary adjustment to
determine the on/off point.
I set up the drive to be on at 0%-25%
throttle and off at more than that. A great
safety feature of the Mcd466 is that when
you turn off the radio, the power to the plug
is off as well.
Finishing assembly are the wheel pants,
which are a breeze to install, and a number
of other parts that you adhere using RC-56
(or equivalent) white glue.
To go a bit further, you can detail the
included dummy engine, make the model a
one-seater by gluing on the included
forward cockpit cover, or make the
instrument panels and install them for both
cockpits. I would have liked it if Great
Planes had included a pilot as well, but it
didn’t so I picked one up at my local hobby
shop.
Bolting everything together for the first
time took close to 10 minutes. The bottom
wing attaches to the fuselage with two nylon
bolts. The upper wing and struts attach with
4-40 screws, washers, and locknuts. Be sure
to have extra of those on hand; they’re sure
to disappear at the field.
All finished, the review YMF-5D came
in at 12.5 pounds ready to fly. That
which is good. And, surprisingly, the CG
was spot on. I was expecting to have to
move things slightly forward.
Flying: Before I took the WACO out to the
field, I watched Great Planes’ online
videos—specifically paying attention to the
speed at which the models were flying. It
worried me that the flying was a tad faster
than with a “scale” look. So for the first
flight I decided to keep the speed up a bit
until I was comfortable with the airplane.
While throttling up on the takeoff roll, it
became apparent that this aircraft was
overpowered to say the least. After a 40- to
50-foot roll, it climbed resembling a Pylon
racer rather than a barnstormer.
After a few trim passes and photo passes
were out of the way, I decided to wring out
the model at full throttle. Holy Toledo!
There was a lot of power there, and the
airframe was more than up to the task.
Huge loops, Cuban eights, and
Immelmann turns were in the YMF-5’s
repertoire at this power level. There wasn’t
enough power to hover, but I don’t think
you’d have much trouble practicing most
novice and advanced RC Aerobatics
maneuvers with this setup.
After tearing up the sky, it was time for
the first landing. Throttling down, the
WACO came in a little hot and completely
overshot the runway. It turns out that even
with all that extra drag, this model was a
floater and didn’t slow as quickly as I
thought it might.
But after a few attempts to figure it out, I
found myself throttling to idle immediately
after turning on the downwind portion of
the landing pattern. The base and final legs
of the pattern were much more manageable
then.
With the next flights, it was time to fly
the YMF-5D as it should be flown: slowly
and gracefully. With the O.S. 95 AX, it
needed only one-third throttle to fly in a
scalelike fashion.
I bumped up the throttle to half for
rolls and loops. At that setting the model
would do anything you might have seen the
full-scale aircraft do, and do well.
Wow, what a great-looking model. As I
mentioned at the start, it had been awhile
since my last Great Planes scale ARF
review—they have come a long way.
So much is done for you at the factory
now. But more than that, numerous
templates and tools are included to make
the work straight, true, and effortless.
Since the first flights I’ve piloted this
ARF many times and am having a ball with
it. It’s a true barnstormer, and Great Planes
has done a fine job with the design.
Experimenting with the flight envelope,
I’ve found that when the model is trimmed
for scale flight (one-third to half throttle),
going to full throttle causes it to climb
rapidly; you and your elevator trim will
become fast friends. But on the low end this
airplane has no tendency to tip stall or do
anything alarming.
Takeoffs need a lot of right rudder to
keep the aircraft pointed down the runway.
Landings are a bit bouncy using the
included foam wheels; I’ll probably switch
those to a softer foam or rubber.
The Sonic-Tronics onboard glow system
has been a great addition and makes starting
the 95 AX a breeze. I installed the indicator
light in the floor of the front cockpit so I
can easily see when the driver is powered
during startup. I’m not sure how long its
onboard battery will last, but I’ve made as
many as eight flights in a day and it still has
power.
Although this YMF-5D is a great
candidate for AMA Fun Scale competition,
the fact that it comes with registration
numbers that couldn’t be found on any fullscale
WACO presents a problem. But after
a bit of research I found a photo that should
do the trick. It’s online, and you can
download it at the website address listed in
the “Sources.” MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
Great Planes Model Manufacturing
Box 9021
Champaign IL 61826
(217) 398-8970
www.greatplanes.com
Sources:
Sonic-Tronics
(888) 721-0128
www.sonictronics.com
1-inch A-style propeller hub:
Tru-Turn
(218) 479-9600
www.tru-turn.com
Master Aircrew
www.masterairscrew.com
WACO photo (courtesy WACO Classic
Aircraft Corporation):
http://bit.ly/gu0hAv
Edition: Model Aviation - 2011/07
Page Numbers: 50,51,52,53,55,57,59
AH, THE GOLDEN Age of Aviation:
the years between World War I and World
War II. There is no other era in which
aircraft design was so elegant,
sophisticated, and simply stunning. The
names roll off of any enthusiasts’ tongues;
they include Beechcraft, Curtiss,
Monocoupe, Travel Air, Aeronca, Cessna,
and so on.
However, when it comes to biplanes
that list of names shrinks substantially.
And a small firm in Troy, Ohio (the Waco
Aircraft Company), designed and
manufactured a beautiful biplane named
the YMF-5.
The review kit is based on a YMF-5D
that the WACO Classic Aircraft
Corporation (Battle Creek, Michigan) is
currently manufacturing. With a wingspan
of 72 inches, this model comes in at
exactly 1/5 scale.
First Impressions: It had been quite a
while since I had the chance to review one
of Great Planes’ big scale ARFs, and I
was looking forward to this one—not only
MonoKote or painted a matching yellow.
The color scheme also included black
trim with red pinstriping. Some of it was
MonoKote, some was painted, and some
was decals.
There are numerous seams, especially on
the fuselage, but nothing to be alarmed
about. After going over all pieces with an
iron to “de-wrinkle,” the only real surprise
was where the covering wrapped around the
lower wing saddle and firewall; it was
trimmed very close to the edge.
Ninety-five percent of the airframe
construction was balsa and plywood. It was
clear that the Great Planes team put a lot of
thought into this model design. There were
also many laser-cut pieces.
Then there was the hardware: items
you’d expect in an ARF, such as clevises,
pushrods, and an engine mount. And there
were other niceties, including foam wheels,
airfoil-shaped wing and cabane struts, a fuel
tank with a double-clunk system, laser-cut
pieces for proper engine spacing, Americansized
screws/nuts, and more. A wealth of
fiberglass parts was included as well.
because of the subject, but to see how these
models had progressed in design and
techniques. I thought it should be a fun
project!
After opening all the packaging, I found
that Great Planes had not only furnished
the kit, but an engine and flight pack to go
with it. The power plant isn’t what would
have been my first choice because it was a
two-stroke.
I would normally choose a four-stroke
for power, but we’ll see how this goes.
Besides, the Great Planes also included a
Bisson Pitts muffler for the size of mount.
When I opened the kit, I saw that
everything was bagged and sectioned off to
protect it from the rigors of shipping. Then
there’s the tape—miles of clear packing
tape holding everything in position. I’ll bet
I spent a good 15 minutes carefully
removing tape from the bags and
packaging!
When I examined the pieces, I was
quickly overcome by a wave of yellow.
There were many parts in this kit, and all
were either covered in yellow Top Flite
The cowl (with blisters) and wheel pants
came with all trim applied. There was a set
of wing fillets and a large, round cover that
could be used to cover the passenger
compartment. The landing gear was not
merely prepainted; it also had the fiberglass
fairing attached and painted in one seamless
piece.
In addition, there was a bag of wooden
pieces—lots of them. A few were obvious—
they were radio trays, etc.—but I was
puzzled about the others. Looking through
the manual, I saw that these parts were
engine-mount spacers and pieces for a
handle that attaches to the cabane struts.
Last but not least was the manual. It
contained 40 pages of highly detailed
information and each step accompanied by
great photography to take away the
guesswork. If you’d like to see how this
project looks before you purchase it, the
manual is available on the Great Planes
website.
This was excellent stuff! Let’s get
started.
Oh, before I go further, this is not a
beginner’s airplane. If you are a newer
builder or pilot, you shouldn’t consider it
for even a second or third model. Great
Planes has done a great job of bringing this
complex design to a simpler level, but you
should take on the YMF-5D ARF only if
you are an intermediate to experienced
modeler.
Assembly: As with all ARF reviews, I
won’t quote the manual step by step.
Instead I’ll gently go over the build and
focus on steps for which a bit more
attention is needed. Let’s start with the
wings.
The ailerons are attached to wooden
blocks, which are then attached to the servo
covers. Pushrods, clevises, and control
horns are installed on each of the four
ailerons. All wires are pulled through the
wing panels using preinstalled strings.
The top wing has small angle brackets
installed, and then the panels are glued
together (two panels for the bottom and
three for the top). Each panel has a set of
dihedral braces that you need to build.
The LE braces have two light-plywood
parts sandwiching an aluminum center
brace. Together they make an incredibly
strong piece. The rear braces are lightplywood
pieces glued together.
Before mixing the epoxy to assemble
each wing, take some extra time to file and
sand the braces so they fit. Originally they
wouldn’t push into the wing slots at all, and
it took a lot of elbow grease to shape them
so they would slide in snugly.
Then assembly moves on to the
fuselage. The landing gear is first, and it’s
extremely straightforward because of all the
work done at the factory.
There is a built-up cover that is glued
into place after the landing gear is attached.
This cover had two small balsa pieces taped
to the bottom; they appeared to be padding
for shipping. Be sure to remove them first.
The manual doesn’t mention this.
The only other thing to note on the gear
is that you’ll have to trim 1/4 inch off of
each main gear axle. That’s easy to do with
a rotary tool and cutoff wheel.
Remember all those extra wood pieces I
mentioned earlier? Here’s where we get to
learn their purpose.
In a few steps those laser-cut plywood
parts are doubled up, and before you know
it you have a cool handle that mounts to the
cabane struts. This handle is perfect for
securely holding and moving the fuselage
with one hand.
Even after everything is in (radio,
engine, etc.), the handle is in the perfect
spot: directly on the CG. It also works well
when you have to flip the fuselage upsidedown
for the other steps; it makes a nice,
flat surface.
Now work switches to the tail, where
the stabilizer halves are installed using a
couple of aluminum tubes that slide into the
fuselage and align everything nicely. Then
the tail wheel is installed.
Note that you will have to enlarge the
cutout in the bottom of the rudder quite a
bit to clear the tail wheel mounts. Once
the cutout is correct, the rudder is
attached using three CA-type hinges.
Rudder and elevator servos, pushrods,
clevises, and control horns are installed
next. There are no surprises here, and all
included hardware works well.
On to the engine. The manual covers
installation of a four-stroke glow and twostroke
gasoline power plant in detail.
However, the O.S. 95 AX two-stroke glow
engine supplied with the review model isn’t
covered at all.
To install the 95 AX, follow the fourstroke
instructions for the first three steps.
The fourth step (wood engine spacers) is
where things change a bit.
Mount the O.S. to the mount. Although
it needs to be installed far forward, the
engine mount has a sharply angled portion
at the front of each mounting beam. Do not
use this area because the mount thins
significantly. I mounted the engine
approximately 1/8 inch aft of this angle.
Then I found that there was not enough
of either wooden mount spacers to get the
correct firewall-to-drive washer distance of
611/16 inches. So, as you can see in the
photo, I combined the two. The rounded
spacers had to be cut as shown, so that the
mounting holes would line up correctly.
When finished I used all six square spacers
and an additional four modified rounded
spacers.
Your measurements might be different,
but heed the 611/16 inches; that is the
minimum distance. A little longer is okay,
but do not shorten this distance.
And be sure that the muffler you use
will clear the firewall. The supplied Bisson
Pitts fit perfectly.
Once you have the proper distance, glue
all the pieces together and fuel-proof them
by either using thinned 30-minute epoxy or
spraying on a coat of clear fuelproof paint.
Now you can return to the manual at the
eighth step of engine installation and finish
bolting the mount to the model, hooking up
the throttle linkage and installing the
throttle servo.
If you go with the two-stroke option, the
throttle pushrod will likely need to be
drilled in a different location than is shown
in the manual.
If you choose to power the YMF-5Dwith a gas engine, the WACO package
includes a few other laser-cut pieces to use
to build an ignition and battery tray that
mounts to the front of the firewall, directly
above the engine. Also included is a
different plastic pushrod to keep ignition
noise away from the radio system. These are
very nice touches.
Most ARFs these days include a fuel
tank, but this is the first I’ve seen that also
includes a double-clunk system. I’ve always
preferred this system, to make it easier to
fill and empty the tank.
The tank is held in the fuselage with a
rubber band. The manual shows how to
install it using a hook, but that didn’t work
for me. Luckily my wife’s hands were the
right size to reach into the small space and
put things right!
The next step is installing the cowl. To
do this, you first need to assemble the pieces
of the cowl centering tool. I had to sand the
cowl opening considerably to allow the ring
to fit. (It’s better to take the weight off of
the model than the tool.)
Once I attained a good fit, I made the
cutout for muffler clearance and engine
cooling.
Mounting the cowl to the fuselage is
designed to be a discreet operation, with
nothing visible from the outside (as on the
full-scale WACO). Two laser-cut lightplywood
rings are included; one bolts to the
fuselage and the other is glued to the inside
of the cowl.
However, it is a challenge to get the
adhesive inside the cowl, with the front
opening complete covered by the centering
tool. The manual simply advises you to
brush on 30-minute epoxy (with fiberglass
filler) and shove on the cowl. This seemed a
bit messy, so I took a slightly different
approach.
I modified the centering tool by cutting
out three large sections so I could carefully
apply the epoxy with a long paintbrush. It
worked like a charm.
The cowl doesn’t have to be epoxied all
the way around—just enough to hold it in
place so it can be carefully removed. Then
you can easily get to the inside and do a
proper job with the epoxy.
The rest of the radio system is a breeze
to install. A large wing-saddle opening
allows even my large hands to get to
everything. Great Planes also includes a
variety of light-plywood templates to make
easy work of cutting holes for the external
switch and charging jack.
I didn’t want to cut a hole in the cowl
through which to stick the glow-plug
igniter. While looking around at options I
contacted Sonic-Tronics to get an opinion
on what I should do.
The company has both a remote Ni-
Starter, which moves the glow plug
connection to a different point (say the
cockpit), and an onboard system, which
Sonic-Tronics thought was the better choice.
That system is normally used on four-stoke
engines to keep the plug hot, but it also
allows you to have onboard “heat” to start
the engine with no external wires.
This system is the Super Mcd466
onboard glow driver: a small, self-contained
driver that has everything you need,
including a charger. The little box works in
parallel with the throttle servo (via a Yharness)
and has a rotary adjustment to
determine the on/off point.
I set up the drive to be on at 0%-25%
throttle and off at more than that. A great
safety feature of the Mcd466 is that when
you turn off the radio, the power to the plug
is off as well.
Finishing assembly are the wheel pants,
which are a breeze to install, and a number
of other parts that you adhere using RC-56
(or equivalent) white glue.
To go a bit further, you can detail the
included dummy engine, make the model a
one-seater by gluing on the included
forward cockpit cover, or make the
instrument panels and install them for both
cockpits. I would have liked it if Great
Planes had included a pilot as well, but it
didn’t so I picked one up at my local hobby
shop.
Bolting everything together for the first
time took close to 10 minutes. The bottom
wing attaches to the fuselage with two nylon
bolts. The upper wing and struts attach with
4-40 screws, washers, and locknuts. Be sure
to have extra of those on hand; they’re sure
to disappear at the field.
All finished, the review YMF-5D came
in at 12.5 pounds ready to fly. That
which is good. And, surprisingly, the CG
was spot on. I was expecting to have to
move things slightly forward.
Flying: Before I took the WACO out to the
field, I watched Great Planes’ online
videos—specifically paying attention to the
speed at which the models were flying. It
worried me that the flying was a tad faster
than with a “scale” look. So for the first
flight I decided to keep the speed up a bit
until I was comfortable with the airplane.
While throttling up on the takeoff roll, it
became apparent that this aircraft was
overpowered to say the least. After a 40- to
50-foot roll, it climbed resembling a Pylon
racer rather than a barnstormer.
After a few trim passes and photo passes
were out of the way, I decided to wring out
the model at full throttle. Holy Toledo!
There was a lot of power there, and the
airframe was more than up to the task.
Huge loops, Cuban eights, and
Immelmann turns were in the YMF-5’s
repertoire at this power level. There wasn’t
enough power to hover, but I don’t think
you’d have much trouble practicing most
novice and advanced RC Aerobatics
maneuvers with this setup.
After tearing up the sky, it was time for
the first landing. Throttling down, the
WACO came in a little hot and completely
overshot the runway. It turns out that even
with all that extra drag, this model was a
floater and didn’t slow as quickly as I
thought it might.
But after a few attempts to figure it out, I
found myself throttling to idle immediately
after turning on the downwind portion of
the landing pattern. The base and final legs
of the pattern were much more manageable
then.
With the next flights, it was time to fly
the YMF-5D as it should be flown: slowly
and gracefully. With the O.S. 95 AX, it
needed only one-third throttle to fly in a
scalelike fashion.
I bumped up the throttle to half for
rolls and loops. At that setting the model
would do anything you might have seen the
full-scale aircraft do, and do well.
Wow, what a great-looking model. As I
mentioned at the start, it had been awhile
since my last Great Planes scale ARF
review—they have come a long way.
So much is done for you at the factory
now. But more than that, numerous
templates and tools are included to make
the work straight, true, and effortless.
Since the first flights I’ve piloted this
ARF many times and am having a ball with
it. It’s a true barnstormer, and Great Planes
has done a fine job with the design.
Experimenting with the flight envelope,
I’ve found that when the model is trimmed
for scale flight (one-third to half throttle),
going to full throttle causes it to climb
rapidly; you and your elevator trim will
become fast friends. But on the low end this
airplane has no tendency to tip stall or do
anything alarming.
Takeoffs need a lot of right rudder to
keep the aircraft pointed down the runway.
Landings are a bit bouncy using the
included foam wheels; I’ll probably switch
those to a softer foam or rubber.
The Sonic-Tronics onboard glow system
has been a great addition and makes starting
the 95 AX a breeze. I installed the indicator
light in the floor of the front cockpit so I
can easily see when the driver is powered
during startup. I’m not sure how long its
onboard battery will last, but I’ve made as
many as eight flights in a day and it still has
power.
Although this YMF-5D is a great
candidate for AMA Fun Scale competition,
the fact that it comes with registration
numbers that couldn’t be found on any fullscale
WACO presents a problem. But after
a bit of research I found a photo that should
do the trick. It’s online, and you can
download it at the website address listed in
the “Sources.” MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
Great Planes Model Manufacturing
Box 9021
Champaign IL 61826
(217) 398-8970
www.greatplanes.com
Sources:
Sonic-Tronics
(888) 721-0128
www.sonictronics.com
1-inch A-style propeller hub:
Tru-Turn
(218) 479-9600
www.tru-turn.com
Master Aircrew
www.masterairscrew.com
WACO photo (courtesy WACO Classic
Aircraft Corporation):
http://bit.ly/gu0hAv
Edition: Model Aviation - 2011/07
Page Numbers: 50,51,52,53,55,57,59
AH, THE GOLDEN Age of Aviation:
the years between World War I and World
War II. There is no other era in which
aircraft design was so elegant,
sophisticated, and simply stunning. The
names roll off of any enthusiasts’ tongues;
they include Beechcraft, Curtiss,
Monocoupe, Travel Air, Aeronca, Cessna,
and so on.
However, when it comes to biplanes
that list of names shrinks substantially.
And a small firm in Troy, Ohio (the Waco
Aircraft Company), designed and
manufactured a beautiful biplane named
the YMF-5.
The review kit is based on a YMF-5D
that the WACO Classic Aircraft
Corporation (Battle Creek, Michigan) is
currently manufacturing. With a wingspan
of 72 inches, this model comes in at
exactly 1/5 scale.
First Impressions: It had been quite a
while since I had the chance to review one
of Great Planes’ big scale ARFs, and I
was looking forward to this one—not only
MonoKote or painted a matching yellow.
The color scheme also included black
trim with red pinstriping. Some of it was
MonoKote, some was painted, and some
was decals.
There are numerous seams, especially on
the fuselage, but nothing to be alarmed
about. After going over all pieces with an
iron to “de-wrinkle,” the only real surprise
was where the covering wrapped around the
lower wing saddle and firewall; it was
trimmed very close to the edge.
Ninety-five percent of the airframe
construction was balsa and plywood. It was
clear that the Great Planes team put a lot of
thought into this model design. There were
also many laser-cut pieces.
Then there was the hardware: items
you’d expect in an ARF, such as clevises,
pushrods, and an engine mount. And there
were other niceties, including foam wheels,
airfoil-shaped wing and cabane struts, a fuel
tank with a double-clunk system, laser-cut
pieces for proper engine spacing, Americansized
screws/nuts, and more. A wealth of
fiberglass parts was included as well.
because of the subject, but to see how these
models had progressed in design and
techniques. I thought it should be a fun
project!
After opening all the packaging, I found
that Great Planes had not only furnished
the kit, but an engine and flight pack to go
with it. The power plant isn’t what would
have been my first choice because it was a
two-stroke.
I would normally choose a four-stroke
for power, but we’ll see how this goes.
Besides, the Great Planes also included a
Bisson Pitts muffler for the size of mount.
When I opened the kit, I saw that
everything was bagged and sectioned off to
protect it from the rigors of shipping. Then
there’s the tape—miles of clear packing
tape holding everything in position. I’ll bet
I spent a good 15 minutes carefully
removing tape from the bags and
packaging!
When I examined the pieces, I was
quickly overcome by a wave of yellow.
There were many parts in this kit, and all
were either covered in yellow Top Flite
The cowl (with blisters) and wheel pants
came with all trim applied. There was a set
of wing fillets and a large, round cover that
could be used to cover the passenger
compartment. The landing gear was not
merely prepainted; it also had the fiberglass
fairing attached and painted in one seamless
piece.
In addition, there was a bag of wooden
pieces—lots of them. A few were obvious—
they were radio trays, etc.—but I was
puzzled about the others. Looking through
the manual, I saw that these parts were
engine-mount spacers and pieces for a
handle that attaches to the cabane struts.
Last but not least was the manual. It
contained 40 pages of highly detailed
information and each step accompanied by
great photography to take away the
guesswork. If you’d like to see how this
project looks before you purchase it, the
manual is available on the Great Planes
website.
This was excellent stuff! Let’s get
started.
Oh, before I go further, this is not a
beginner’s airplane. If you are a newer
builder or pilot, you shouldn’t consider it
for even a second or third model. Great
Planes has done a great job of bringing this
complex design to a simpler level, but you
should take on the YMF-5D ARF only if
you are an intermediate to experienced
modeler.
Assembly: As with all ARF reviews, I
won’t quote the manual step by step.
Instead I’ll gently go over the build and
focus on steps for which a bit more
attention is needed. Let’s start with the
wings.
The ailerons are attached to wooden
blocks, which are then attached to the servo
covers. Pushrods, clevises, and control
horns are installed on each of the four
ailerons. All wires are pulled through the
wing panels using preinstalled strings.
The top wing has small angle brackets
installed, and then the panels are glued
together (two panels for the bottom and
three for the top). Each panel has a set of
dihedral braces that you need to build.
The LE braces have two light-plywood
parts sandwiching an aluminum center
brace. Together they make an incredibly
strong piece. The rear braces are lightplywood
pieces glued together.
Before mixing the epoxy to assemble
each wing, take some extra time to file and
sand the braces so they fit. Originally they
wouldn’t push into the wing slots at all, and
it took a lot of elbow grease to shape them
so they would slide in snugly.
Then assembly moves on to the
fuselage. The landing gear is first, and it’s
extremely straightforward because of all the
work done at the factory.
There is a built-up cover that is glued
into place after the landing gear is attached.
This cover had two small balsa pieces taped
to the bottom; they appeared to be padding
for shipping. Be sure to remove them first.
The manual doesn’t mention this.
The only other thing to note on the gear
is that you’ll have to trim 1/4 inch off of
each main gear axle. That’s easy to do with
a rotary tool and cutoff wheel.
Remember all those extra wood pieces I
mentioned earlier? Here’s where we get to
learn their purpose.
In a few steps those laser-cut plywood
parts are doubled up, and before you know
it you have a cool handle that mounts to the
cabane struts. This handle is perfect for
securely holding and moving the fuselage
with one hand.
Even after everything is in (radio,
engine, etc.), the handle is in the perfect
spot: directly on the CG. It also works well
when you have to flip the fuselage upsidedown
for the other steps; it makes a nice,
flat surface.
Now work switches to the tail, where
the stabilizer halves are installed using a
couple of aluminum tubes that slide into the
fuselage and align everything nicely. Then
the tail wheel is installed.
Note that you will have to enlarge the
cutout in the bottom of the rudder quite a
bit to clear the tail wheel mounts. Once
the cutout is correct, the rudder is
attached using three CA-type hinges.
Rudder and elevator servos, pushrods,
clevises, and control horns are installed
next. There are no surprises here, and all
included hardware works well.
On to the engine. The manual covers
installation of a four-stroke glow and twostroke
gasoline power plant in detail.
However, the O.S. 95 AX two-stroke glow
engine supplied with the review model isn’t
covered at all.
To install the 95 AX, follow the fourstroke
instructions for the first three steps.
The fourth step (wood engine spacers) is
where things change a bit.
Mount the O.S. to the mount. Although
it needs to be installed far forward, the
engine mount has a sharply angled portion
at the front of each mounting beam. Do not
use this area because the mount thins
significantly. I mounted the engine
approximately 1/8 inch aft of this angle.
Then I found that there was not enough
of either wooden mount spacers to get the
correct firewall-to-drive washer distance of
611/16 inches. So, as you can see in the
photo, I combined the two. The rounded
spacers had to be cut as shown, so that the
mounting holes would line up correctly.
When finished I used all six square spacers
and an additional four modified rounded
spacers.
Your measurements might be different,
but heed the 611/16 inches; that is the
minimum distance. A little longer is okay,
but do not shorten this distance.
And be sure that the muffler you use
will clear the firewall. The supplied Bisson
Pitts fit perfectly.
Once you have the proper distance, glue
all the pieces together and fuel-proof them
by either using thinned 30-minute epoxy or
spraying on a coat of clear fuelproof paint.
Now you can return to the manual at the
eighth step of engine installation and finish
bolting the mount to the model, hooking up
the throttle linkage and installing the
throttle servo.
If you go with the two-stroke option, the
throttle pushrod will likely need to be
drilled in a different location than is shown
in the manual.
If you choose to power the YMF-5Dwith a gas engine, the WACO package
includes a few other laser-cut pieces to use
to build an ignition and battery tray that
mounts to the front of the firewall, directly
above the engine. Also included is a
different plastic pushrod to keep ignition
noise away from the radio system. These are
very nice touches.
Most ARFs these days include a fuel
tank, but this is the first I’ve seen that also
includes a double-clunk system. I’ve always
preferred this system, to make it easier to
fill and empty the tank.
The tank is held in the fuselage with a
rubber band. The manual shows how to
install it using a hook, but that didn’t work
for me. Luckily my wife’s hands were the
right size to reach into the small space and
put things right!
The next step is installing the cowl. To
do this, you first need to assemble the pieces
of the cowl centering tool. I had to sand the
cowl opening considerably to allow the ring
to fit. (It’s better to take the weight off of
the model than the tool.)
Once I attained a good fit, I made the
cutout for muffler clearance and engine
cooling.
Mounting the cowl to the fuselage is
designed to be a discreet operation, with
nothing visible from the outside (as on the
full-scale WACO). Two laser-cut lightplywood
rings are included; one bolts to the
fuselage and the other is glued to the inside
of the cowl.
However, it is a challenge to get the
adhesive inside the cowl, with the front
opening complete covered by the centering
tool. The manual simply advises you to
brush on 30-minute epoxy (with fiberglass
filler) and shove on the cowl. This seemed a
bit messy, so I took a slightly different
approach.
I modified the centering tool by cutting
out three large sections so I could carefully
apply the epoxy with a long paintbrush. It
worked like a charm.
The cowl doesn’t have to be epoxied all
the way around—just enough to hold it in
place so it can be carefully removed. Then
you can easily get to the inside and do a
proper job with the epoxy.
The rest of the radio system is a breeze
to install. A large wing-saddle opening
allows even my large hands to get to
everything. Great Planes also includes a
variety of light-plywood templates to make
easy work of cutting holes for the external
switch and charging jack.
I didn’t want to cut a hole in the cowl
through which to stick the glow-plug
igniter. While looking around at options I
contacted Sonic-Tronics to get an opinion
on what I should do.
The company has both a remote Ni-
Starter, which moves the glow plug
connection to a different point (say the
cockpit), and an onboard system, which
Sonic-Tronics thought was the better choice.
That system is normally used on four-stoke
engines to keep the plug hot, but it also
allows you to have onboard “heat” to start
the engine with no external wires.
This system is the Super Mcd466
onboard glow driver: a small, self-contained
driver that has everything you need,
including a charger. The little box works in
parallel with the throttle servo (via a Yharness)
and has a rotary adjustment to
determine the on/off point.
I set up the drive to be on at 0%-25%
throttle and off at more than that. A great
safety feature of the Mcd466 is that when
you turn off the radio, the power to the plug
is off as well.
Finishing assembly are the wheel pants,
which are a breeze to install, and a number
of other parts that you adhere using RC-56
(or equivalent) white glue.
To go a bit further, you can detail the
included dummy engine, make the model a
one-seater by gluing on the included
forward cockpit cover, or make the
instrument panels and install them for both
cockpits. I would have liked it if Great
Planes had included a pilot as well, but it
didn’t so I picked one up at my local hobby
shop.
Bolting everything together for the first
time took close to 10 minutes. The bottom
wing attaches to the fuselage with two nylon
bolts. The upper wing and struts attach with
4-40 screws, washers, and locknuts. Be sure
to have extra of those on hand; they’re sure
to disappear at the field.
All finished, the review YMF-5D came
in at 12.5 pounds ready to fly. That
which is good. And, surprisingly, the CG
was spot on. I was expecting to have to
move things slightly forward.
Flying: Before I took the WACO out to the
field, I watched Great Planes’ online
videos—specifically paying attention to the
speed at which the models were flying. It
worried me that the flying was a tad faster
than with a “scale” look. So for the first
flight I decided to keep the speed up a bit
until I was comfortable with the airplane.
While throttling up on the takeoff roll, it
became apparent that this aircraft was
overpowered to say the least. After a 40- to
50-foot roll, it climbed resembling a Pylon
racer rather than a barnstormer.
After a few trim passes and photo passes
were out of the way, I decided to wring out
the model at full throttle. Holy Toledo!
There was a lot of power there, and the
airframe was more than up to the task.
Huge loops, Cuban eights, and
Immelmann turns were in the YMF-5’s
repertoire at this power level. There wasn’t
enough power to hover, but I don’t think
you’d have much trouble practicing most
novice and advanced RC Aerobatics
maneuvers with this setup.
After tearing up the sky, it was time for
the first landing. Throttling down, the
WACO came in a little hot and completely
overshot the runway. It turns out that even
with all that extra drag, this model was a
floater and didn’t slow as quickly as I
thought it might.
But after a few attempts to figure it out, I
found myself throttling to idle immediately
after turning on the downwind portion of
the landing pattern. The base and final legs
of the pattern were much more manageable
then.
With the next flights, it was time to fly
the YMF-5D as it should be flown: slowly
and gracefully. With the O.S. 95 AX, it
needed only one-third throttle to fly in a
scalelike fashion.
I bumped up the throttle to half for
rolls and loops. At that setting the model
would do anything you might have seen the
full-scale aircraft do, and do well.
Wow, what a great-looking model. As I
mentioned at the start, it had been awhile
since my last Great Planes scale ARF
review—they have come a long way.
So much is done for you at the factory
now. But more than that, numerous
templates and tools are included to make
the work straight, true, and effortless.
Since the first flights I’ve piloted this
ARF many times and am having a ball with
it. It’s a true barnstormer, and Great Planes
has done a fine job with the design.
Experimenting with the flight envelope,
I’ve found that when the model is trimmed
for scale flight (one-third to half throttle),
going to full throttle causes it to climb
rapidly; you and your elevator trim will
become fast friends. But on the low end this
airplane has no tendency to tip stall or do
anything alarming.
Takeoffs need a lot of right rudder to
keep the aircraft pointed down the runway.
Landings are a bit bouncy using the
included foam wheels; I’ll probably switch
those to a softer foam or rubber.
The Sonic-Tronics onboard glow system
has been a great addition and makes starting
the 95 AX a breeze. I installed the indicator
light in the floor of the front cockpit so I
can easily see when the driver is powered
during startup. I’m not sure how long its
onboard battery will last, but I’ve made as
many as eight flights in a day and it still has
power.
Although this YMF-5D is a great
candidate for AMA Fun Scale competition,
the fact that it comes with registration
numbers that couldn’t be found on any fullscale
WACO presents a problem. But after
a bit of research I found a photo that should
do the trick. It’s online, and you can
download it at the website address listed in
the “Sources.” MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
Great Planes Model Manufacturing
Box 9021
Champaign IL 61826
(217) 398-8970
www.greatplanes.com
Sources:
Sonic-Tronics
(888) 721-0128
www.sonictronics.com
1-inch A-style propeller hub:
Tru-Turn
(218) 479-9600
www.tru-turn.com
Master Aircrew
www.masterairscrew.com
WACO photo (courtesy WACO Classic
Aircraft Corporation):
http://bit.ly/gu0hAv
Edition: Model Aviation - 2011/07
Page Numbers: 50,51,52,53,55,57,59
AH, THE GOLDEN Age of Aviation:
the years between World War I and World
War II. There is no other era in which
aircraft design was so elegant,
sophisticated, and simply stunning. The
names roll off of any enthusiasts’ tongues;
they include Beechcraft, Curtiss,
Monocoupe, Travel Air, Aeronca, Cessna,
and so on.
However, when it comes to biplanes
that list of names shrinks substantially.
And a small firm in Troy, Ohio (the Waco
Aircraft Company), designed and
manufactured a beautiful biplane named
the YMF-5.
The review kit is based on a YMF-5D
that the WACO Classic Aircraft
Corporation (Battle Creek, Michigan) is
currently manufacturing. With a wingspan
of 72 inches, this model comes in at
exactly 1/5 scale.
First Impressions: It had been quite a
while since I had the chance to review one
of Great Planes’ big scale ARFs, and I
was looking forward to this one—not only
MonoKote or painted a matching yellow.
The color scheme also included black
trim with red pinstriping. Some of it was
MonoKote, some was painted, and some
was decals.
There are numerous seams, especially on
the fuselage, but nothing to be alarmed
about. After going over all pieces with an
iron to “de-wrinkle,” the only real surprise
was where the covering wrapped around the
lower wing saddle and firewall; it was
trimmed very close to the edge.
Ninety-five percent of the airframe
construction was balsa and plywood. It was
clear that the Great Planes team put a lot of
thought into this model design. There were
also many laser-cut pieces.
Then there was the hardware: items
you’d expect in an ARF, such as clevises,
pushrods, and an engine mount. And there
were other niceties, including foam wheels,
airfoil-shaped wing and cabane struts, a fuel
tank with a double-clunk system, laser-cut
pieces for proper engine spacing, Americansized
screws/nuts, and more. A wealth of
fiberglass parts was included as well.
because of the subject, but to see how these
models had progressed in design and
techniques. I thought it should be a fun
project!
After opening all the packaging, I found
that Great Planes had not only furnished
the kit, but an engine and flight pack to go
with it. The power plant isn’t what would
have been my first choice because it was a
two-stroke.
I would normally choose a four-stroke
for power, but we’ll see how this goes.
Besides, the Great Planes also included a
Bisson Pitts muffler for the size of mount.
When I opened the kit, I saw that
everything was bagged and sectioned off to
protect it from the rigors of shipping. Then
there’s the tape—miles of clear packing
tape holding everything in position. I’ll bet
I spent a good 15 minutes carefully
removing tape from the bags and
packaging!
When I examined the pieces, I was
quickly overcome by a wave of yellow.
There were many parts in this kit, and all
were either covered in yellow Top Flite
The cowl (with blisters) and wheel pants
came with all trim applied. There was a set
of wing fillets and a large, round cover that
could be used to cover the passenger
compartment. The landing gear was not
merely prepainted; it also had the fiberglass
fairing attached and painted in one seamless
piece.
In addition, there was a bag of wooden
pieces—lots of them. A few were obvious—
they were radio trays, etc.—but I was
puzzled about the others. Looking through
the manual, I saw that these parts were
engine-mount spacers and pieces for a
handle that attaches to the cabane struts.
Last but not least was the manual. It
contained 40 pages of highly detailed
information and each step accompanied by
great photography to take away the
guesswork. If you’d like to see how this
project looks before you purchase it, the
manual is available on the Great Planes
website.
This was excellent stuff! Let’s get
started.
Oh, before I go further, this is not a
beginner’s airplane. If you are a newer
builder or pilot, you shouldn’t consider it
for even a second or third model. Great
Planes has done a great job of bringing this
complex design to a simpler level, but you
should take on the YMF-5D ARF only if
you are an intermediate to experienced
modeler.
Assembly: As with all ARF reviews, I
won’t quote the manual step by step.
Instead I’ll gently go over the build and
focus on steps for which a bit more
attention is needed. Let’s start with the
wings.
The ailerons are attached to wooden
blocks, which are then attached to the servo
covers. Pushrods, clevises, and control
horns are installed on each of the four
ailerons. All wires are pulled through the
wing panels using preinstalled strings.
The top wing has small angle brackets
installed, and then the panels are glued
together (two panels for the bottom and
three for the top). Each panel has a set of
dihedral braces that you need to build.
The LE braces have two light-plywood
parts sandwiching an aluminum center
brace. Together they make an incredibly
strong piece. The rear braces are lightplywood
pieces glued together.
Before mixing the epoxy to assemble
each wing, take some extra time to file and
sand the braces so they fit. Originally they
wouldn’t push into the wing slots at all, and
it took a lot of elbow grease to shape them
so they would slide in snugly.
Then assembly moves on to the
fuselage. The landing gear is first, and it’s
extremely straightforward because of all the
work done at the factory.
There is a built-up cover that is glued
into place after the landing gear is attached.
This cover had two small balsa pieces taped
to the bottom; they appeared to be padding
for shipping. Be sure to remove them first.
The manual doesn’t mention this.
The only other thing to note on the gear
is that you’ll have to trim 1/4 inch off of
each main gear axle. That’s easy to do with
a rotary tool and cutoff wheel.
Remember all those extra wood pieces I
mentioned earlier? Here’s where we get to
learn their purpose.
In a few steps those laser-cut plywood
parts are doubled up, and before you know
it you have a cool handle that mounts to the
cabane struts. This handle is perfect for
securely holding and moving the fuselage
with one hand.
Even after everything is in (radio,
engine, etc.), the handle is in the perfect
spot: directly on the CG. It also works well
when you have to flip the fuselage upsidedown
for the other steps; it makes a nice,
flat surface.
Now work switches to the tail, where
the stabilizer halves are installed using a
couple of aluminum tubes that slide into the
fuselage and align everything nicely. Then
the tail wheel is installed.
Note that you will have to enlarge the
cutout in the bottom of the rudder quite a
bit to clear the tail wheel mounts. Once
the cutout is correct, the rudder is
attached using three CA-type hinges.
Rudder and elevator servos, pushrods,
clevises, and control horns are installed
next. There are no surprises here, and all
included hardware works well.
On to the engine. The manual covers
installation of a four-stroke glow and twostroke
gasoline power plant in detail.
However, the O.S. 95 AX two-stroke glow
engine supplied with the review model isn’t
covered at all.
To install the 95 AX, follow the fourstroke
instructions for the first three steps.
The fourth step (wood engine spacers) is
where things change a bit.
Mount the O.S. to the mount. Although
it needs to be installed far forward, the
engine mount has a sharply angled portion
at the front of each mounting beam. Do not
use this area because the mount thins
significantly. I mounted the engine
approximately 1/8 inch aft of this angle.
Then I found that there was not enough
of either wooden mount spacers to get the
correct firewall-to-drive washer distance of
611/16 inches. So, as you can see in the
photo, I combined the two. The rounded
spacers had to be cut as shown, so that the
mounting holes would line up correctly.
When finished I used all six square spacers
and an additional four modified rounded
spacers.
Your measurements might be different,
but heed the 611/16 inches; that is the
minimum distance. A little longer is okay,
but do not shorten this distance.
And be sure that the muffler you use
will clear the firewall. The supplied Bisson
Pitts fit perfectly.
Once you have the proper distance, glue
all the pieces together and fuel-proof them
by either using thinned 30-minute epoxy or
spraying on a coat of clear fuelproof paint.
Now you can return to the manual at the
eighth step of engine installation and finish
bolting the mount to the model, hooking up
the throttle linkage and installing the
throttle servo.
If you go with the two-stroke option, the
throttle pushrod will likely need to be
drilled in a different location than is shown
in the manual.
If you choose to power the YMF-5Dwith a gas engine, the WACO package
includes a few other laser-cut pieces to use
to build an ignition and battery tray that
mounts to the front of the firewall, directly
above the engine. Also included is a
different plastic pushrod to keep ignition
noise away from the radio system. These are
very nice touches.
Most ARFs these days include a fuel
tank, but this is the first I’ve seen that also
includes a double-clunk system. I’ve always
preferred this system, to make it easier to
fill and empty the tank.
The tank is held in the fuselage with a
rubber band. The manual shows how to
install it using a hook, but that didn’t work
for me. Luckily my wife’s hands were the
right size to reach into the small space and
put things right!
The next step is installing the cowl. To
do this, you first need to assemble the pieces
of the cowl centering tool. I had to sand the
cowl opening considerably to allow the ring
to fit. (It’s better to take the weight off of
the model than the tool.)
Once I attained a good fit, I made the
cutout for muffler clearance and engine
cooling.
Mounting the cowl to the fuselage is
designed to be a discreet operation, with
nothing visible from the outside (as on the
full-scale WACO). Two laser-cut lightplywood
rings are included; one bolts to the
fuselage and the other is glued to the inside
of the cowl.
However, it is a challenge to get the
adhesive inside the cowl, with the front
opening complete covered by the centering
tool. The manual simply advises you to
brush on 30-minute epoxy (with fiberglass
filler) and shove on the cowl. This seemed a
bit messy, so I took a slightly different
approach.
I modified the centering tool by cutting
out three large sections so I could carefully
apply the epoxy with a long paintbrush. It
worked like a charm.
The cowl doesn’t have to be epoxied all
the way around—just enough to hold it in
place so it can be carefully removed. Then
you can easily get to the inside and do a
proper job with the epoxy.
The rest of the radio system is a breeze
to install. A large wing-saddle opening
allows even my large hands to get to
everything. Great Planes also includes a
variety of light-plywood templates to make
easy work of cutting holes for the external
switch and charging jack.
I didn’t want to cut a hole in the cowl
through which to stick the glow-plug
igniter. While looking around at options I
contacted Sonic-Tronics to get an opinion
on what I should do.
The company has both a remote Ni-
Starter, which moves the glow plug
connection to a different point (say the
cockpit), and an onboard system, which
Sonic-Tronics thought was the better choice.
That system is normally used on four-stoke
engines to keep the plug hot, but it also
allows you to have onboard “heat” to start
the engine with no external wires.
This system is the Super Mcd466
onboard glow driver: a small, self-contained
driver that has everything you need,
including a charger. The little box works in
parallel with the throttle servo (via a Yharness)
and has a rotary adjustment to
determine the on/off point.
I set up the drive to be on at 0%-25%
throttle and off at more than that. A great
safety feature of the Mcd466 is that when
you turn off the radio, the power to the plug
is off as well.
Finishing assembly are the wheel pants,
which are a breeze to install, and a number
of other parts that you adhere using RC-56
(or equivalent) white glue.
To go a bit further, you can detail the
included dummy engine, make the model a
one-seater by gluing on the included
forward cockpit cover, or make the
instrument panels and install them for both
cockpits. I would have liked it if Great
Planes had included a pilot as well, but it
didn’t so I picked one up at my local hobby
shop.
Bolting everything together for the first
time took close to 10 minutes. The bottom
wing attaches to the fuselage with two nylon
bolts. The upper wing and struts attach with
4-40 screws, washers, and locknuts. Be sure
to have extra of those on hand; they’re sure
to disappear at the field.
All finished, the review YMF-5D came
in at 12.5 pounds ready to fly. That
which is good. And, surprisingly, the CG
was spot on. I was expecting to have to
move things slightly forward.
Flying: Before I took the WACO out to the
field, I watched Great Planes’ online
videos—specifically paying attention to the
speed at which the models were flying. It
worried me that the flying was a tad faster
than with a “scale” look. So for the first
flight I decided to keep the speed up a bit
until I was comfortable with the airplane.
While throttling up on the takeoff roll, it
became apparent that this aircraft was
overpowered to say the least. After a 40- to
50-foot roll, it climbed resembling a Pylon
racer rather than a barnstormer.
After a few trim passes and photo passes
were out of the way, I decided to wring out
the model at full throttle. Holy Toledo!
There was a lot of power there, and the
airframe was more than up to the task.
Huge loops, Cuban eights, and
Immelmann turns were in the YMF-5’s
repertoire at this power level. There wasn’t
enough power to hover, but I don’t think
you’d have much trouble practicing most
novice and advanced RC Aerobatics
maneuvers with this setup.
After tearing up the sky, it was time for
the first landing. Throttling down, the
WACO came in a little hot and completely
overshot the runway. It turns out that even
with all that extra drag, this model was a
floater and didn’t slow as quickly as I
thought it might.
But after a few attempts to figure it out, I
found myself throttling to idle immediately
after turning on the downwind portion of
the landing pattern. The base and final legs
of the pattern were much more manageable
then.
With the next flights, it was time to fly
the YMF-5D as it should be flown: slowly
and gracefully. With the O.S. 95 AX, it
needed only one-third throttle to fly in a
scalelike fashion.
I bumped up the throttle to half for
rolls and loops. At that setting the model
would do anything you might have seen the
full-scale aircraft do, and do well.
Wow, what a great-looking model. As I
mentioned at the start, it had been awhile
since my last Great Planes scale ARF
review—they have come a long way.
So much is done for you at the factory
now. But more than that, numerous
templates and tools are included to make
the work straight, true, and effortless.
Since the first flights I’ve piloted this
ARF many times and am having a ball with
it. It’s a true barnstormer, and Great Planes
has done a fine job with the design.
Experimenting with the flight envelope,
I’ve found that when the model is trimmed
for scale flight (one-third to half throttle),
going to full throttle causes it to climb
rapidly; you and your elevator trim will
become fast friends. But on the low end this
airplane has no tendency to tip stall or do
anything alarming.
Takeoffs need a lot of right rudder to
keep the aircraft pointed down the runway.
Landings are a bit bouncy using the
included foam wheels; I’ll probably switch
those to a softer foam or rubber.
The Sonic-Tronics onboard glow system
has been a great addition and makes starting
the 95 AX a breeze. I installed the indicator
light in the floor of the front cockpit so I
can easily see when the driver is powered
during startup. I’m not sure how long its
onboard battery will last, but I’ve made as
many as eight flights in a day and it still has
power.
Although this YMF-5D is a great
candidate for AMA Fun Scale competition,
the fact that it comes with registration
numbers that couldn’t be found on any fullscale
WACO presents a problem. But after
a bit of research I found a photo that should
do the trick. It’s online, and you can
download it at the website address listed in
the “Sources.” MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
Great Planes Model Manufacturing
Box 9021
Champaign IL 61826
(217) 398-8970
www.greatplanes.com
Sources:
Sonic-Tronics
(888) 721-0128
www.sonictronics.com
1-inch A-style propeller hub:
Tru-Turn
(218) 479-9600
www.tru-turn.com
Master Aircrew
www.masterairscrew.com
WACO photo (courtesy WACO Classic
Aircraft Corporation):
http://bit.ly/gu0hAv
Edition: Model Aviation - 2011/07
Page Numbers: 50,51,52,53,55,57,59
AH, THE GOLDEN Age of Aviation:
the years between World War I and World
War II. There is no other era in which
aircraft design was so elegant,
sophisticated, and simply stunning. The
names roll off of any enthusiasts’ tongues;
they include Beechcraft, Curtiss,
Monocoupe, Travel Air, Aeronca, Cessna,
and so on.
However, when it comes to biplanes
that list of names shrinks substantially.
And a small firm in Troy, Ohio (the Waco
Aircraft Company), designed and
manufactured a beautiful biplane named
the YMF-5.
The review kit is based on a YMF-5D
that the WACO Classic Aircraft
Corporation (Battle Creek, Michigan) is
currently manufacturing. With a wingspan
of 72 inches, this model comes in at
exactly 1/5 scale.
First Impressions: It had been quite a
while since I had the chance to review one
of Great Planes’ big scale ARFs, and I
was looking forward to this one—not only
MonoKote or painted a matching yellow.
The color scheme also included black
trim with red pinstriping. Some of it was
MonoKote, some was painted, and some
was decals.
There are numerous seams, especially on
the fuselage, but nothing to be alarmed
about. After going over all pieces with an
iron to “de-wrinkle,” the only real surprise
was where the covering wrapped around the
lower wing saddle and firewall; it was
trimmed very close to the edge.
Ninety-five percent of the airframe
construction was balsa and plywood. It was
clear that the Great Planes team put a lot of
thought into this model design. There were
also many laser-cut pieces.
Then there was the hardware: items
you’d expect in an ARF, such as clevises,
pushrods, and an engine mount. And there
were other niceties, including foam wheels,
airfoil-shaped wing and cabane struts, a fuel
tank with a double-clunk system, laser-cut
pieces for proper engine spacing, Americansized
screws/nuts, and more. A wealth of
fiberglass parts was included as well.
because of the subject, but to see how these
models had progressed in design and
techniques. I thought it should be a fun
project!
After opening all the packaging, I found
that Great Planes had not only furnished
the kit, but an engine and flight pack to go
with it. The power plant isn’t what would
have been my first choice because it was a
two-stroke.
I would normally choose a four-stroke
for power, but we’ll see how this goes.
Besides, the Great Planes also included a
Bisson Pitts muffler for the size of mount.
When I opened the kit, I saw that
everything was bagged and sectioned off to
protect it from the rigors of shipping. Then
there’s the tape—miles of clear packing
tape holding everything in position. I’ll bet
I spent a good 15 minutes carefully
removing tape from the bags and
packaging!
When I examined the pieces, I was
quickly overcome by a wave of yellow.
There were many parts in this kit, and all
were either covered in yellow Top Flite
The cowl (with blisters) and wheel pants
came with all trim applied. There was a set
of wing fillets and a large, round cover that
could be used to cover the passenger
compartment. The landing gear was not
merely prepainted; it also had the fiberglass
fairing attached and painted in one seamless
piece.
In addition, there was a bag of wooden
pieces—lots of them. A few were obvious—
they were radio trays, etc.—but I was
puzzled about the others. Looking through
the manual, I saw that these parts were
engine-mount spacers and pieces for a
handle that attaches to the cabane struts.
Last but not least was the manual. It
contained 40 pages of highly detailed
information and each step accompanied by
great photography to take away the
guesswork. If you’d like to see how this
project looks before you purchase it, the
manual is available on the Great Planes
website.
This was excellent stuff! Let’s get
started.
Oh, before I go further, this is not a
beginner’s airplane. If you are a newer
builder or pilot, you shouldn’t consider it
for even a second or third model. Great
Planes has done a great job of bringing this
complex design to a simpler level, but you
should take on the YMF-5D ARF only if
you are an intermediate to experienced
modeler.
Assembly: As with all ARF reviews, I
won’t quote the manual step by step.
Instead I’ll gently go over the build and
focus on steps for which a bit more
attention is needed. Let’s start with the
wings.
The ailerons are attached to wooden
blocks, which are then attached to the servo
covers. Pushrods, clevises, and control
horns are installed on each of the four
ailerons. All wires are pulled through the
wing panels using preinstalled strings.
The top wing has small angle brackets
installed, and then the panels are glued
together (two panels for the bottom and
three for the top). Each panel has a set of
dihedral braces that you need to build.
The LE braces have two light-plywood
parts sandwiching an aluminum center
brace. Together they make an incredibly
strong piece. The rear braces are lightplywood
pieces glued together.
Before mixing the epoxy to assemble
each wing, take some extra time to file and
sand the braces so they fit. Originally they
wouldn’t push into the wing slots at all, and
it took a lot of elbow grease to shape them
so they would slide in snugly.
Then assembly moves on to the
fuselage. The landing gear is first, and it’s
extremely straightforward because of all the
work done at the factory.
There is a built-up cover that is glued
into place after the landing gear is attached.
This cover had two small balsa pieces taped
to the bottom; they appeared to be padding
for shipping. Be sure to remove them first.
The manual doesn’t mention this.
The only other thing to note on the gear
is that you’ll have to trim 1/4 inch off of
each main gear axle. That’s easy to do with
a rotary tool and cutoff wheel.
Remember all those extra wood pieces I
mentioned earlier? Here’s where we get to
learn their purpose.
In a few steps those laser-cut plywood
parts are doubled up, and before you know
it you have a cool handle that mounts to the
cabane struts. This handle is perfect for
securely holding and moving the fuselage
with one hand.
Even after everything is in (radio,
engine, etc.), the handle is in the perfect
spot: directly on the CG. It also works well
when you have to flip the fuselage upsidedown
for the other steps; it makes a nice,
flat surface.
Now work switches to the tail, where
the stabilizer halves are installed using a
couple of aluminum tubes that slide into the
fuselage and align everything nicely. Then
the tail wheel is installed.
Note that you will have to enlarge the
cutout in the bottom of the rudder quite a
bit to clear the tail wheel mounts. Once
the cutout is correct, the rudder is
attached using three CA-type hinges.
Rudder and elevator servos, pushrods,
clevises, and control horns are installed
next. There are no surprises here, and all
included hardware works well.
On to the engine. The manual covers
installation of a four-stroke glow and twostroke
gasoline power plant in detail.
However, the O.S. 95 AX two-stroke glow
engine supplied with the review model isn’t
covered at all.
To install the 95 AX, follow the fourstroke
instructions for the first three steps.
The fourth step (wood engine spacers) is
where things change a bit.
Mount the O.S. to the mount. Although
it needs to be installed far forward, the
engine mount has a sharply angled portion
at the front of each mounting beam. Do not
use this area because the mount thins
significantly. I mounted the engine
approximately 1/8 inch aft of this angle.
Then I found that there was not enough
of either wooden mount spacers to get the
correct firewall-to-drive washer distance of
611/16 inches. So, as you can see in the
photo, I combined the two. The rounded
spacers had to be cut as shown, so that the
mounting holes would line up correctly.
When finished I used all six square spacers
and an additional four modified rounded
spacers.
Your measurements might be different,
but heed the 611/16 inches; that is the
minimum distance. A little longer is okay,
but do not shorten this distance.
And be sure that the muffler you use
will clear the firewall. The supplied Bisson
Pitts fit perfectly.
Once you have the proper distance, glue
all the pieces together and fuel-proof them
by either using thinned 30-minute epoxy or
spraying on a coat of clear fuelproof paint.
Now you can return to the manual at the
eighth step of engine installation and finish
bolting the mount to the model, hooking up
the throttle linkage and installing the
throttle servo.
If you go with the two-stroke option, the
throttle pushrod will likely need to be
drilled in a different location than is shown
in the manual.
If you choose to power the YMF-5Dwith a gas engine, the WACO package
includes a few other laser-cut pieces to use
to build an ignition and battery tray that
mounts to the front of the firewall, directly
above the engine. Also included is a
different plastic pushrod to keep ignition
noise away from the radio system. These are
very nice touches.
Most ARFs these days include a fuel
tank, but this is the first I’ve seen that also
includes a double-clunk system. I’ve always
preferred this system, to make it easier to
fill and empty the tank.
The tank is held in the fuselage with a
rubber band. The manual shows how to
install it using a hook, but that didn’t work
for me. Luckily my wife’s hands were the
right size to reach into the small space and
put things right!
The next step is installing the cowl. To
do this, you first need to assemble the pieces
of the cowl centering tool. I had to sand the
cowl opening considerably to allow the ring
to fit. (It’s better to take the weight off of
the model than the tool.)
Once I attained a good fit, I made the
cutout for muffler clearance and engine
cooling.
Mounting the cowl to the fuselage is
designed to be a discreet operation, with
nothing visible from the outside (as on the
full-scale WACO). Two laser-cut lightplywood
rings are included; one bolts to the
fuselage and the other is glued to the inside
of the cowl.
However, it is a challenge to get the
adhesive inside the cowl, with the front
opening complete covered by the centering
tool. The manual simply advises you to
brush on 30-minute epoxy (with fiberglass
filler) and shove on the cowl. This seemed a
bit messy, so I took a slightly different
approach.
I modified the centering tool by cutting
out three large sections so I could carefully
apply the epoxy with a long paintbrush. It
worked like a charm.
The cowl doesn’t have to be epoxied all
the way around—just enough to hold it in
place so it can be carefully removed. Then
you can easily get to the inside and do a
proper job with the epoxy.
The rest of the radio system is a breeze
to install. A large wing-saddle opening
allows even my large hands to get to
everything. Great Planes also includes a
variety of light-plywood templates to make
easy work of cutting holes for the external
switch and charging jack.
I didn’t want to cut a hole in the cowl
through which to stick the glow-plug
igniter. While looking around at options I
contacted Sonic-Tronics to get an opinion
on what I should do.
The company has both a remote Ni-
Starter, which moves the glow plug
connection to a different point (say the
cockpit), and an onboard system, which
Sonic-Tronics thought was the better choice.
That system is normally used on four-stoke
engines to keep the plug hot, but it also
allows you to have onboard “heat” to start
the engine with no external wires.
This system is the Super Mcd466
onboard glow driver: a small, self-contained
driver that has everything you need,
including a charger. The little box works in
parallel with the throttle servo (via a Yharness)
and has a rotary adjustment to
determine the on/off point.
I set up the drive to be on at 0%-25%
throttle and off at more than that. A great
safety feature of the Mcd466 is that when
you turn off the radio, the power to the plug
is off as well.
Finishing assembly are the wheel pants,
which are a breeze to install, and a number
of other parts that you adhere using RC-56
(or equivalent) white glue.
To go a bit further, you can detail the
included dummy engine, make the model a
one-seater by gluing on the included
forward cockpit cover, or make the
instrument panels and install them for both
cockpits. I would have liked it if Great
Planes had included a pilot as well, but it
didn’t so I picked one up at my local hobby
shop.
Bolting everything together for the first
time took close to 10 minutes. The bottom
wing attaches to the fuselage with two nylon
bolts. The upper wing and struts attach with
4-40 screws, washers, and locknuts. Be sure
to have extra of those on hand; they’re sure
to disappear at the field.
All finished, the review YMF-5D came
in at 12.5 pounds ready to fly. That
which is good. And, surprisingly, the CG
was spot on. I was expecting to have to
move things slightly forward.
Flying: Before I took the WACO out to the
field, I watched Great Planes’ online
videos—specifically paying attention to the
speed at which the models were flying. It
worried me that the flying was a tad faster
than with a “scale” look. So for the first
flight I decided to keep the speed up a bit
until I was comfortable with the airplane.
While throttling up on the takeoff roll, it
became apparent that this aircraft was
overpowered to say the least. After a 40- to
50-foot roll, it climbed resembling a Pylon
racer rather than a barnstormer.
After a few trim passes and photo passes
were out of the way, I decided to wring out
the model at full throttle. Holy Toledo!
There was a lot of power there, and the
airframe was more than up to the task.
Huge loops, Cuban eights, and
Immelmann turns were in the YMF-5’s
repertoire at this power level. There wasn’t
enough power to hover, but I don’t think
you’d have much trouble practicing most
novice and advanced RC Aerobatics
maneuvers with this setup.
After tearing up the sky, it was time for
the first landing. Throttling down, the
WACO came in a little hot and completely
overshot the runway. It turns out that even
with all that extra drag, this model was a
floater and didn’t slow as quickly as I
thought it might.
But after a few attempts to figure it out, I
found myself throttling to idle immediately
after turning on the downwind portion of
the landing pattern. The base and final legs
of the pattern were much more manageable
then.
With the next flights, it was time to fly
the YMF-5D as it should be flown: slowly
and gracefully. With the O.S. 95 AX, it
needed only one-third throttle to fly in a
scalelike fashion.
I bumped up the throttle to half for
rolls and loops. At that setting the model
would do anything you might have seen the
full-scale aircraft do, and do well.
Wow, what a great-looking model. As I
mentioned at the start, it had been awhile
since my last Great Planes scale ARF
review—they have come a long way.
So much is done for you at the factory
now. But more than that, numerous
templates and tools are included to make
the work straight, true, and effortless.
Since the first flights I’ve piloted this
ARF many times and am having a ball with
it. It’s a true barnstormer, and Great Planes
has done a fine job with the design.
Experimenting with the flight envelope,
I’ve found that when the model is trimmed
for scale flight (one-third to half throttle),
going to full throttle causes it to climb
rapidly; you and your elevator trim will
become fast friends. But on the low end this
airplane has no tendency to tip stall or do
anything alarming.
Takeoffs need a lot of right rudder to
keep the aircraft pointed down the runway.
Landings are a bit bouncy using the
included foam wheels; I’ll probably switch
those to a softer foam or rubber.
The Sonic-Tronics onboard glow system
has been a great addition and makes starting
the 95 AX a breeze. I installed the indicator
light in the floor of the front cockpit so I
can easily see when the driver is powered
during startup. I’m not sure how long its
onboard battery will last, but I’ve made as
many as eight flights in a day and it still has
power.
Although this YMF-5D is a great
candidate for AMA Fun Scale competition,
the fact that it comes with registration
numbers that couldn’t be found on any fullscale
WACO presents a problem. But after
a bit of research I found a photo that should
do the trick. It’s online, and you can
download it at the website address listed in
the “Sources.” MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
Great Planes Model Manufacturing
Box 9021
Champaign IL 61826
(217) 398-8970
www.greatplanes.com
Sources:
Sonic-Tronics
(888) 721-0128
www.sonictronics.com
1-inch A-style propeller hub:
Tru-Turn
(218) 479-9600
www.tru-turn.com
Master Aircrew
www.masterairscrew.com
WACO photo (courtesy WACO Classic
Aircraft Corporation):
http://bit.ly/gu0hAv
Edition: Model Aviation - 2011/07
Page Numbers: 50,51,52,53,55,57,59
AH, THE GOLDEN Age of Aviation:
the years between World War I and World
War II. There is no other era in which
aircraft design was so elegant,
sophisticated, and simply stunning. The
names roll off of any enthusiasts’ tongues;
they include Beechcraft, Curtiss,
Monocoupe, Travel Air, Aeronca, Cessna,
and so on.
However, when it comes to biplanes
that list of names shrinks substantially.
And a small firm in Troy, Ohio (the Waco
Aircraft Company), designed and
manufactured a beautiful biplane named
the YMF-5.
The review kit is based on a YMF-5D
that the WACO Classic Aircraft
Corporation (Battle Creek, Michigan) is
currently manufacturing. With a wingspan
of 72 inches, this model comes in at
exactly 1/5 scale.
First Impressions: It had been quite a
while since I had the chance to review one
of Great Planes’ big scale ARFs, and I
was looking forward to this one—not only
MonoKote or painted a matching yellow.
The color scheme also included black
trim with red pinstriping. Some of it was
MonoKote, some was painted, and some
was decals.
There are numerous seams, especially on
the fuselage, but nothing to be alarmed
about. After going over all pieces with an
iron to “de-wrinkle,” the only real surprise
was where the covering wrapped around the
lower wing saddle and firewall; it was
trimmed very close to the edge.
Ninety-five percent of the airframe
construction was balsa and plywood. It was
clear that the Great Planes team put a lot of
thought into this model design. There were
also many laser-cut pieces.
Then there was the hardware: items
you’d expect in an ARF, such as clevises,
pushrods, and an engine mount. And there
were other niceties, including foam wheels,
airfoil-shaped wing and cabane struts, a fuel
tank with a double-clunk system, laser-cut
pieces for proper engine spacing, Americansized
screws/nuts, and more. A wealth of
fiberglass parts was included as well.
because of the subject, but to see how these
models had progressed in design and
techniques. I thought it should be a fun
project!
After opening all the packaging, I found
that Great Planes had not only furnished
the kit, but an engine and flight pack to go
with it. The power plant isn’t what would
have been my first choice because it was a
two-stroke.
I would normally choose a four-stroke
for power, but we’ll see how this goes.
Besides, the Great Planes also included a
Bisson Pitts muffler for the size of mount.
When I opened the kit, I saw that
everything was bagged and sectioned off to
protect it from the rigors of shipping. Then
there’s the tape—miles of clear packing
tape holding everything in position. I’ll bet
I spent a good 15 minutes carefully
removing tape from the bags and
packaging!
When I examined the pieces, I was
quickly overcome by a wave of yellow.
There were many parts in this kit, and all
were either covered in yellow Top Flite
The cowl (with blisters) and wheel pants
came with all trim applied. There was a set
of wing fillets and a large, round cover that
could be used to cover the passenger
compartment. The landing gear was not
merely prepainted; it also had the fiberglass
fairing attached and painted in one seamless
piece.
In addition, there was a bag of wooden
pieces—lots of them. A few were obvious—
they were radio trays, etc.—but I was
puzzled about the others. Looking through
the manual, I saw that these parts were
engine-mount spacers and pieces for a
handle that attaches to the cabane struts.
Last but not least was the manual. It
contained 40 pages of highly detailed
information and each step accompanied by
great photography to take away the
guesswork. If you’d like to see how this
project looks before you purchase it, the
manual is available on the Great Planes
website.
This was excellent stuff! Let’s get
started.
Oh, before I go further, this is not a
beginner’s airplane. If you are a newer
builder or pilot, you shouldn’t consider it
for even a second or third model. Great
Planes has done a great job of bringing this
complex design to a simpler level, but you
should take on the YMF-5D ARF only if
you are an intermediate to experienced
modeler.
Assembly: As with all ARF reviews, I
won’t quote the manual step by step.
Instead I’ll gently go over the build and
focus on steps for which a bit more
attention is needed. Let’s start with the
wings.
The ailerons are attached to wooden
blocks, which are then attached to the servo
covers. Pushrods, clevises, and control
horns are installed on each of the four
ailerons. All wires are pulled through the
wing panels using preinstalled strings.
The top wing has small angle brackets
installed, and then the panels are glued
together (two panels for the bottom and
three for the top). Each panel has a set of
dihedral braces that you need to build.
The LE braces have two light-plywood
parts sandwiching an aluminum center
brace. Together they make an incredibly
strong piece. The rear braces are lightplywood
pieces glued together.
Before mixing the epoxy to assemble
each wing, take some extra time to file and
sand the braces so they fit. Originally they
wouldn’t push into the wing slots at all, and
it took a lot of elbow grease to shape them
so they would slide in snugly.
Then assembly moves on to the
fuselage. The landing gear is first, and it’s
extremely straightforward because of all the
work done at the factory.
There is a built-up cover that is glued
into place after the landing gear is attached.
This cover had two small balsa pieces taped
to the bottom; they appeared to be padding
for shipping. Be sure to remove them first.
The manual doesn’t mention this.
The only other thing to note on the gear
is that you’ll have to trim 1/4 inch off of
each main gear axle. That’s easy to do with
a rotary tool and cutoff wheel.
Remember all those extra wood pieces I
mentioned earlier? Here’s where we get to
learn their purpose.
In a few steps those laser-cut plywood
parts are doubled up, and before you know
it you have a cool handle that mounts to the
cabane struts. This handle is perfect for
securely holding and moving the fuselage
with one hand.
Even after everything is in (radio,
engine, etc.), the handle is in the perfect
spot: directly on the CG. It also works well
when you have to flip the fuselage upsidedown
for the other steps; it makes a nice,
flat surface.
Now work switches to the tail, where
the stabilizer halves are installed using a
couple of aluminum tubes that slide into the
fuselage and align everything nicely. Then
the tail wheel is installed.
Note that you will have to enlarge the
cutout in the bottom of the rudder quite a
bit to clear the tail wheel mounts. Once
the cutout is correct, the rudder is
attached using three CA-type hinges.
Rudder and elevator servos, pushrods,
clevises, and control horns are installed
next. There are no surprises here, and all
included hardware works well.
On to the engine. The manual covers
installation of a four-stroke glow and twostroke
gasoline power plant in detail.
However, the O.S. 95 AX two-stroke glow
engine supplied with the review model isn’t
covered at all.
To install the 95 AX, follow the fourstroke
instructions for the first three steps.
The fourth step (wood engine spacers) is
where things change a bit.
Mount the O.S. to the mount. Although
it needs to be installed far forward, the
engine mount has a sharply angled portion
at the front of each mounting beam. Do not
use this area because the mount thins
significantly. I mounted the engine
approximately 1/8 inch aft of this angle.
Then I found that there was not enough
of either wooden mount spacers to get the
correct firewall-to-drive washer distance of
611/16 inches. So, as you can see in the
photo, I combined the two. The rounded
spacers had to be cut as shown, so that the
mounting holes would line up correctly.
When finished I used all six square spacers
and an additional four modified rounded
spacers.
Your measurements might be different,
but heed the 611/16 inches; that is the
minimum distance. A little longer is okay,
but do not shorten this distance.
And be sure that the muffler you use
will clear the firewall. The supplied Bisson
Pitts fit perfectly.
Once you have the proper distance, glue
all the pieces together and fuel-proof them
by either using thinned 30-minute epoxy or
spraying on a coat of clear fuelproof paint.
Now you can return to the manual at the
eighth step of engine installation and finish
bolting the mount to the model, hooking up
the throttle linkage and installing the
throttle servo.
If you go with the two-stroke option, the
throttle pushrod will likely need to be
drilled in a different location than is shown
in the manual.
If you choose to power the YMF-5Dwith a gas engine, the WACO package
includes a few other laser-cut pieces to use
to build an ignition and battery tray that
mounts to the front of the firewall, directly
above the engine. Also included is a
different plastic pushrod to keep ignition
noise away from the radio system. These are
very nice touches.
Most ARFs these days include a fuel
tank, but this is the first I’ve seen that also
includes a double-clunk system. I’ve always
preferred this system, to make it easier to
fill and empty the tank.
The tank is held in the fuselage with a
rubber band. The manual shows how to
install it using a hook, but that didn’t work
for me. Luckily my wife’s hands were the
right size to reach into the small space and
put things right!
The next step is installing the cowl. To
do this, you first need to assemble the pieces
of the cowl centering tool. I had to sand the
cowl opening considerably to allow the ring
to fit. (It’s better to take the weight off of
the model than the tool.)
Once I attained a good fit, I made the
cutout for muffler clearance and engine
cooling.
Mounting the cowl to the fuselage is
designed to be a discreet operation, with
nothing visible from the outside (as on the
full-scale WACO). Two laser-cut lightplywood
rings are included; one bolts to the
fuselage and the other is glued to the inside
of the cowl.
However, it is a challenge to get the
adhesive inside the cowl, with the front
opening complete covered by the centering
tool. The manual simply advises you to
brush on 30-minute epoxy (with fiberglass
filler) and shove on the cowl. This seemed a
bit messy, so I took a slightly different
approach.
I modified the centering tool by cutting
out three large sections so I could carefully
apply the epoxy with a long paintbrush. It
worked like a charm.
The cowl doesn’t have to be epoxied all
the way around—just enough to hold it in
place so it can be carefully removed. Then
you can easily get to the inside and do a
proper job with the epoxy.
The rest of the radio system is a breeze
to install. A large wing-saddle opening
allows even my large hands to get to
everything. Great Planes also includes a
variety of light-plywood templates to make
easy work of cutting holes for the external
switch and charging jack.
I didn’t want to cut a hole in the cowl
through which to stick the glow-plug
igniter. While looking around at options I
contacted Sonic-Tronics to get an opinion
on what I should do.
The company has both a remote Ni-
Starter, which moves the glow plug
connection to a different point (say the
cockpit), and an onboard system, which
Sonic-Tronics thought was the better choice.
That system is normally used on four-stoke
engines to keep the plug hot, but it also
allows you to have onboard “heat” to start
the engine with no external wires.
This system is the Super Mcd466
onboard glow driver: a small, self-contained
driver that has everything you need,
including a charger. The little box works in
parallel with the throttle servo (via a Yharness)
and has a rotary adjustment to
determine the on/off point.
I set up the drive to be on at 0%-25%
throttle and off at more than that. A great
safety feature of the Mcd466 is that when
you turn off the radio, the power to the plug
is off as well.
Finishing assembly are the wheel pants,
which are a breeze to install, and a number
of other parts that you adhere using RC-56
(or equivalent) white glue.
To go a bit further, you can detail the
included dummy engine, make the model a
one-seater by gluing on the included
forward cockpit cover, or make the
instrument panels and install them for both
cockpits. I would have liked it if Great
Planes had included a pilot as well, but it
didn’t so I picked one up at my local hobby
shop.
Bolting everything together for the first
time took close to 10 minutes. The bottom
wing attaches to the fuselage with two nylon
bolts. The upper wing and struts attach with
4-40 screws, washers, and locknuts. Be sure
to have extra of those on hand; they’re sure
to disappear at the field.
All finished, the review YMF-5D came
in at 12.5 pounds ready to fly. That
which is good. And, surprisingly, the CG
was spot on. I was expecting to have to
move things slightly forward.
Flying: Before I took the WACO out to the
field, I watched Great Planes’ online
videos—specifically paying attention to the
speed at which the models were flying. It
worried me that the flying was a tad faster
than with a “scale” look. So for the first
flight I decided to keep the speed up a bit
until I was comfortable with the airplane.
While throttling up on the takeoff roll, it
became apparent that this aircraft was
overpowered to say the least. After a 40- to
50-foot roll, it climbed resembling a Pylon
racer rather than a barnstormer.
After a few trim passes and photo passes
were out of the way, I decided to wring out
the model at full throttle. Holy Toledo!
There was a lot of power there, and the
airframe was more than up to the task.
Huge loops, Cuban eights, and
Immelmann turns were in the YMF-5’s
repertoire at this power level. There wasn’t
enough power to hover, but I don’t think
you’d have much trouble practicing most
novice and advanced RC Aerobatics
maneuvers with this setup.
After tearing up the sky, it was time for
the first landing. Throttling down, the
WACO came in a little hot and completely
overshot the runway. It turns out that even
with all that extra drag, this model was a
floater and didn’t slow as quickly as I
thought it might.
But after a few attempts to figure it out, I
found myself throttling to idle immediately
after turning on the downwind portion of
the landing pattern. The base and final legs
of the pattern were much more manageable
then.
With the next flights, it was time to fly
the YMF-5D as it should be flown: slowly
and gracefully. With the O.S. 95 AX, it
needed only one-third throttle to fly in a
scalelike fashion.
I bumped up the throttle to half for
rolls and loops. At that setting the model
would do anything you might have seen the
full-scale aircraft do, and do well.
Wow, what a great-looking model. As I
mentioned at the start, it had been awhile
since my last Great Planes scale ARF
review—they have come a long way.
So much is done for you at the factory
now. But more than that, numerous
templates and tools are included to make
the work straight, true, and effortless.
Since the first flights I’ve piloted this
ARF many times and am having a ball with
it. It’s a true barnstormer, and Great Planes
has done a fine job with the design.
Experimenting with the flight envelope,
I’ve found that when the model is trimmed
for scale flight (one-third to half throttle),
going to full throttle causes it to climb
rapidly; you and your elevator trim will
become fast friends. But on the low end this
airplane has no tendency to tip stall or do
anything alarming.
Takeoffs need a lot of right rudder to
keep the aircraft pointed down the runway.
Landings are a bit bouncy using the
included foam wheels; I’ll probably switch
those to a softer foam or rubber.
The Sonic-Tronics onboard glow system
has been a great addition and makes starting
the 95 AX a breeze. I installed the indicator
light in the floor of the front cockpit so I
can easily see when the driver is powered
during startup. I’m not sure how long its
onboard battery will last, but I’ve made as
many as eight flights in a day and it still has
power.
Although this YMF-5D is a great
candidate for AMA Fun Scale competition,
the fact that it comes with registration
numbers that couldn’t be found on any fullscale
WACO presents a problem. But after
a bit of research I found a photo that should
do the trick. It’s online, and you can
download it at the website address listed in
the “Sources.” MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
Great Planes Model Manufacturing
Box 9021
Champaign IL 61826
(217) 398-8970
www.greatplanes.com
Sources:
Sonic-Tronics
(888) 721-0128
www.sonictronics.com
1-inch A-style propeller hub:
Tru-Turn
(218) 479-9600
www.tru-turn.com
Master Aircrew
www.masterairscrew.com
WACO photo (courtesy WACO Classic
Aircraft Corporation):
http://bit.ly/gu0hAv