60 MODEL AVIATION
MICHAEL RAMSEY
Plane Talk: Stevens AeroModel Edge 540 3D Kit
Below: The music-wire landing gear is
dressed with balsa fairings. The balsa
wheel pants are nearly
indestructible and
effortlessly covered
with So-Lite
film.
Left: The Edge excels in 3-D aerobatics,
thanks to its light wing loading and high
power-to-weight ratio. Building this
aircraft to be a tight machine is simple.
Above: The framed Edge 540 fuselage is
rigid even without covering. The fuselage
sheeting is etched on the inside to fit the
curves more easily.
A fun build that will
have ’em wowed
at the field
A STEVENS AEROMODEL project is a modern affirmation that
the rewards of constructing an airplane from a kit are alive and well.
This experience may also be considered solid proof that many of the
torturous tasks involved in building light and straight are a thing of
the past.
A skilled engineer and draftsman, Bill Stevens has produced an
RC kit line that is solely electric-power based. The models range in
size from those that are suitable for inside a school gym to those that
are fully 3-D-capable and suitable for the club field.
Although Bill’s packaging methods are minimalist (a plastic bag
for a kit container), the sweet filling is in the kit parts’ exquisitely
detailed engineering and production. It’s a good trade, if you ask me.
The Stevens AeroModel Edge 540 appealed to me the most
because it is much like many ARFs that are available. Silly, huh?
Why buy the kit if you can purchase the ARF?
Those “other” models are fine, but Bill engineered his Edge to be
an excellent performer in the precision and 3-D styles of flight. I
wouldn’t have to compromise laser-cutting technology that is found
in many ARFs to build the model myself, exactly as I wanted it to
be. Furthermore, this model would offer a personal look into the
evolution of design and construction techniques.
This Edge incorporates much of what laser cutting has brought to
the production of current models in weight savings and strength
techniques. With its provided full-size plans and clearly written and
04sig2.QXD 2/24/09 10:01 AM Page 60
April 2009 61
+•
Comes as complete laser-cut kit with all necessary
hardware.
• All-wood airframe construction with laser etching for
added accuracy.
• Tab-lock construction for a strong airframe and
components that build according to plan.
• Exceptionally well-written and illustrated instruction
manual includes flight instruction and total setup
requirements.
• Recommended motor system leaves nothing to be
desired by Unlimited and 3-D pilots.
• Edge 540’s practical size is stable enough for the
intermediate RC pilot.
• Model is easy enough to build for the first-time
modeler.
• Entire construction process requires only one .5-ounce
bottle of thin cyanoacrylate.
-•
LE sheeting joint is fragile.
• Two-piece ABS cowling. (Fiberglass would be heavier,
though.)
Pluses and Minuses
Model type: RC Scale Unlimited 3-D kit
Skill level: Beginner builder, intermediate pilot
Wingspan: 50 inches
Wing area: 440 square inches
Length: 45 inches
Weight: 28-32 ounces
Wing loading: 9.8 ounces/square foot
Power (recommended): 350-watt system
Radio: Four channels (minimum), four miniservos
Construction: Balsa, light plywood, ABS cowl, clear
canopy
Covering/finish: Iron-on film (So-Lite recommended)
Price: $147.99
Motor: Hacker A30-16M (1060 Kv)
Speed control: Hacker X-40
Battery: 3S Thunder Power Extreme 2070 mAh
Propeller: APC 12 x 6E
Motor current: Highest draw 32 amps
Motor voltage: 10.4 under load
Motor output: 354 watts
Radio system: JR 6102 transmitter, JR R610UL
receiver, JR Sport SM22 miniservos, two 6-inch servo
extensions
Finish: Navy, red, white, and transparent yellow So-Lite;
matching Rust-Oleum paint
Weight: 38.8 ounces (33.9 ounces without battery)
Flight duration: Five to eight minutes
Specifications and Test-Model Details
The wing panels are supported with a carbon-fiber tube. The fit is
tight, so no sheath is needed. Sheeting joinery is tabbed.
Joint fits are tight. Parts lock into tabs, to assure a square
structure. The latest kits include carbon-fiber reinforcement for
elevator and rudder.
Photos by the author and Mark Lanterman
The Edge is covered before final
installation of the tail pieces. Servo
locations promote linkage setups
that are stiff and slop-free.
illustrated instruction and flight manual, the model is not only easy
to complete, but it is also well built, requires minimal experience,
and doesn’t call for elaborate tools from the builder.
The wood parts use tab-lock construction. When glued into place,
very little carving or fancy sanding is required to complete the
airframe’s finished shape. The Edge is built primarily with 1/16 and
1/8 balsa and 1mm and 3mm plywood. To keep weight down, only
where stress is expected to be high is plywood employed.
The clear canopy is vacuum-formed and fits neatly, with a
flanged front that offers plenty of gluing area. The cowling is two
pieces of vacuum-formed ABS plastic that require careful trimming
and fitting, since the material is purposefully thin and flexible. The
04sig2.QXD 2/24/09 10:01 AM Page 61
builder has the option of dressing the prebent music-wire landing gear
with scrap-balsa fairings. (It’s a nice finishing touch.)
I take back the comment about carving and shaping. The wheel
pants are made from 1/4 balsa layers that include 1mm and 3mm
plywood reinforcement. So you might be able to build the model on the
dining room table and not get yelled at; the wheel pants, on the other
hand, need to be taken out to the porch for shaping. It makes a mess.
When finished, these wheel pants are close to indestructible. I guess
the satisfaction of the result was so gratifying that I forgot about the
small amount of work it took to make them look nice. Covering them
with matching So-Lite wasn’t difficult either.
The equipment I chose for the project mostly consists of items
offered on Stevens AeroModel’s Web site. You can purchase
everything you need for this model from one source.
I used my JR 6102 transmitter and JR Sport servos, since I had
them on hand and they matched the specifications. But the power
system is exactly what Bill recommends and designed the model
around.
The Hacker A30-16M is a beautiful motor. I went with the
matching Hacker X-40 brushless controller, even though the system
was expected to pull only 30 amps. I found this system to be every bit
as good as other reviews have claimed it is.
For such a small package, I have yet to find a setup that is as
capable—or as quiet. And, quite frankly, a 175-watt-per-pound
airplane was an experience I didn’t want to pass up. That kind of highend
performance is often too expensive and/or impractical. This is a
small model with a big attitude.
Construction: Only the parts needed for the specific assembly are
removed from the wood sheets, which keeps everything
organized. All of the components are laser cut and fit exactly; no
fiddling is necessary.
The tail surfaces are built first, which is a perfect catalyst for
getting those
building brain cells
activated. When
completed, those flat
frame pieces are 1/8-
inch-thick, with
1mm plywood
laminated over the
joiner-wire stress
points.
Being familiar
with typical stickand-
sheet
construction (the
labor of), when the
tail was assembled
without glue, as
recommended, I was
62 MODEL AVIATION
The LE sheeting tab-locks to the ribs, ensuring airfoil shape and
rib alignment. JR Sport SM22 servos are used throughout, with
Du-Bro heavy-duty servo arms.
A 3S 2100-2500 mAh Li-Poly battery straps to a long plywood tray
that will accommodate almost any CG preference.
Underneath the large cowling is the recommended Hacker A30-16
motor and X-40 speed control. The anodized Tru-Turn spinner for
electrics promotes cooling and smooth operation.
Inverted flight requires a tiny amount of
forward stick pressure to maintain heading.
Precision aerobatics potential is almost
unlimited.
The Stevens Edge can fly from short grass as well as pavement.
Landings can be slowed to an airspeed that resembles a crawl.
04sig2.QXD 2/24/09 10:01 AM Page 62
able to pick up the assembly from the fullsize
plans sheet and handle it almost as if it
were all glued together. I have to admit that
this made me giggle; the security of the parts
led to premonitions of a fun and successful
build project—and a short one at that.
The laser cut leaves a beveled edge,
which is accounted for by the engineer. The
correct orientation of the parts will produce
a tight glue joint on both sides of the
assembly. Thin cyanoacrylate is the best
glue for securing the joints—all the parts,
actually. Dry-fitting is good for confirming
the accuracy of alignment before joinery is
made permanent.
Provided with my kit as a gift (maybe
everyone gets one) was a Sanding Block
Dual Grit 60/100. Its semisoft inner material
allows the user to easily hold the tool and
quickly rough out round LEs and bevel
hinge areas. Later I wrapped the block with
220- and 400-grit paper for finish-sanding.
The fuselage takes shape from the
bottom up, starting with constructing the
lower frame. This assembly includes the
magnetically secured battery hatch. Only
two magnets (don’t get the polarity wrong)
are included, but you have the option of
securing the wing panels with magnets as
well. Slick.
The laser-cut holes in the parts for the
magnet are basically a “snap-tight” fit.
Again, this part-fit phenomenon assures the
builder; there is little opportunity for the
sometimes delicate framework to go
crooked, although it did happen once.
I got a little forceful while attaching the
wing-root sheeting on the left wing panel.
My excessive pressure warped the TE
downward, which was obvious after
following the laser-etched hinge lines that
pointed straight to my blunder, which was
corrected.
The front half of the fuselage includes a
light-plywood box that carries the stress
loads of the power system, landing gear, and
wing spar. All of the fuselage subassemblies
build off of that inner frame.
Besides being cut accurately, the cool
thing about the forward and aft turtledeck
sheeting is the laser-etched kerf cuts that
allow the material to wrap around without
requiring a time-consuming molding
technique.
The build was fun, almost like plug-andplay.
When a part was needed, I plugged it
onto the tab-lock location and moved
forward. I found it helpful to use a long
glue-tip extender on the bottle of thin
cyanoacrylate to precisely apply the
adhesive. Overapplying glue can be a major
weight-gain point.
The wings are built and installed as a
two-piece system. Each half plugs into a
carbon-fiber tube that fits inside a lightplywood
box within the fuselage. The fit is
tight on the carbon-fiber tube, making
removal of the wings difficult.
I soaped the tube for easier installation
and secured each wing half with a 6-32
thumbscrew through the root—not an
optional magnet. I can change my mind
later.
The motor box is mounted to the
fuselage with 4-40 socket-head screws. The
box itself also locks in the music-wire
landing gear. Saturate the plywood gearstrut
channel with lots of thin cyanoacrylate.
This will ensure that the bangs and bumps of
rough-field flying won’t loosen their
satisfyingly tight fit.
Even the wing LE sheeting is tabbed
onto the ribs; it’s a beautiful thing! The one
part I didn’t like (and it’s about the only
thing) is that the sheeting on my kit was too
short at the LE to be sanded flush with the
ribs.
This means that only the top corner of
the LE cap touches the sheeting. Maybe I
sanded too much, but I had to resecure the
sheeting several times while blending in the
LE shape. The easy fix would be to add a
1/16-inch square strip to the sheeting and
sand the area flush.
Carbon-fiber strips on the TEs of the
ailerons, elevator, and rudder keep those
surfaces from warping—during the build
and while covering. The ailerons themselves
are works of art; the hinge area is built up—
not a solid, thick piece of balsa that needs to
be carved and sanded to a beveled edge; the
bevel is built in. (Happy sigh.)
The kit supplies all hardware needed to
complete the Edge. These pieces are a
mixture of laser-cut and Du-Bro parts that
accurately attach at the locations that laser
etching pinpoints. Use extremely light coats
of Bondo glazing putty to smooth the joint
on the cowling; the joint is in the scale
location, so filling is an option—not
required.
The airframe is plenty strong without
covering, so lightweight heat-shrink film
such as So-Lite works well. With the threeview
provided in the manual, an original
color scheme that looks sporty yet shows off
the model’s elegant framework was
accomplished.
I have transparent covering on the
bottom and white covering the upper areas
and fuselage. I found So-Lite to be a delight
to use, even though its properties are more
delicate than those of the robust MonoKote
and standard UltraCote, the use of which
would weight down this airplane.
I layered the navy and red onto the white
using the Windex method, but applying the
same colors over the transparent yellow
required heat to activate their adhesives.
Maybe the transparent colors have a surface
tack-proof coating.
So-Lite is incredibly pliable and will tack
back onto itself with just the heat from the
builder’s skin or breath, so be careful. I was
able to cover each balsa wheel pant in two
pieces; the seam runs down the center, front
to back. My sock-covered iron at 220°
helped me pull and tug the covering around,
free of wrinkles.
The ready-made servo openings in the
wings and tail area were the perfect fit for
my JR Sport SM22 servos. I installed Du-
Bro’s extra-strength servo arms to get the
needed throws for 3-D control and E/Z
Connectors on the short metal pushrods.
For fun, I programmed the ailerons into
the Flaperon function of the JR6102
transmitter so I can play with flaps or spoiler
functions later.
Flying the Edge: This 25-size model’s
ground handling is pretty good in short grass,
and the wide-stance undercarriage offers lots
of propeller clearance. I chose a Thunder
Power 18C 2070 mAh 3S Li-Poly pack to fuel
the Hacker motor system. To balance, the
battery mounts close to the CG; this means I
can experiment with different packs.
I measured the output by throttling up the
assembled aircraft and holding on for dear
life. Quite confidently, I could hold the
model in almost any attitude, let go at full
throttle, and it would fly up out of sight.
ROG (rise-off-ground) takeoffs at half
throttle are graceful yet still short, especially
with a mild headwind.
I’ve tested the Edge in conditions gusting
at 20 mph; although it gets tossed around, it
never let me feel out of control. It’s a blast
to fly in wind, actually.
I haven’t needed to play with CG points,
because from the first flight the Edge
handled neutrally in both upright and
inverted attitudes. The built-in engine thrust
benefits the model when power is applied
suddenly; however, the generous rudder area
compensates to an almost infinite amount.
I’ve programmed the dual rate functions
so that high rate can move the surfaces to
the limits but has 60%-70% exponential
(expo) to soften the input at the center of the
stick. Low rate control is 50% of the high
rate and has 10%-30% expo again for the
same purpose. I have no trouble landing and
taking off on high rates with this setup, but
my confidence is high with more than 50
flights now on the model.
The Edge, with its straight-LE wing, is
well suited for 3-D and high-G turning.
Harrier, Parachute, and Elevator maneuvers
benefited from a small mount of spoiler
mixed into the elevator input; it canceled
most of the wing rocking.
There tends to be a slight wiggle in
heading at high speeds, which is why the
vertical fin is as tall as it is. Scale Aerobatics
look great when the airspeed is managed,
which means that full throttle is mostly used
for straight-up portions of aerobatics or
emergency purposes. Can you say, “Yeeha!”?
I’d Do It Again: Since the point at which the
Stevens AeroModel Edge was halfway built,
I’ve wanted to build another. The experience
is so positive and enjoyable that it has
empowered me to want to create and build
more on a regular basis. Maybe I’ll try Bill’s
RV-4 next, but the Edge’s performance has
me looking hard at his CAP 232.
I leave my Edge 540 assembled, since its
50-inch span fits easily in my Toyota
4Runner. My model came out slightly
heavier than specified, probably because of
my cowl paint job and servo hardware; there
might be an ounce to be saved there. Having
flown the model in and out of the specified
flight envelope, the slightly higher wing
loading isn’t at all upsetting.
I still can’t get over that this size
model weighs just a hair more than 2
pounds. The engineering and wood
choices have much to do with that, I
suppose. Back in the day when kits were
more popular, we were happy with a
model this size weighing sometimes
twice as much. If Bill Stevens’ models
were available then, I doubt we’d be such
an ARF dominated hobby/sport. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Stevens AeroModel
1528 S. Nevada Ave.
Colorado Springs CO 80905
(719) 387-4187
www.stevensaero.com
Items Used In Review:
JR radio system:
JR Radios
(800) 338-4639
www.jrradios.com
Thunder Power batteries:
Thunder Power RC
(702) 228-8883
www.thunderpowerrc.com
Hacker A30-16M motor:
Hacker Brushless Motors
(480) 726-7519
www.hackerbrushless.com
Other Printed Reviews:
No information available at time of
publication.
Edition: Model Aviation - 2009/04
Page Numbers: 60,61,62,64,65
Edition: Model Aviation - 2009/04
Page Numbers: 60,61,62,64,65
60 MODEL AVIATION
MICHAEL RAMSEY
Plane Talk: Stevens AeroModel Edge 540 3D Kit
Below: The music-wire landing gear is
dressed with balsa fairings. The balsa
wheel pants are nearly
indestructible and
effortlessly covered
with So-Lite
film.
Left: The Edge excels in 3-D aerobatics,
thanks to its light wing loading and high
power-to-weight ratio. Building this
aircraft to be a tight machine is simple.
Above: The framed Edge 540 fuselage is
rigid even without covering. The fuselage
sheeting is etched on the inside to fit the
curves more easily.
A fun build that will
have ’em wowed
at the field
A STEVENS AEROMODEL project is a modern affirmation that
the rewards of constructing an airplane from a kit are alive and well.
This experience may also be considered solid proof that many of the
torturous tasks involved in building light and straight are a thing of
the past.
A skilled engineer and draftsman, Bill Stevens has produced an
RC kit line that is solely electric-power based. The models range in
size from those that are suitable for inside a school gym to those that
are fully 3-D-capable and suitable for the club field.
Although Bill’s packaging methods are minimalist (a plastic bag
for a kit container), the sweet filling is in the kit parts’ exquisitely
detailed engineering and production. It’s a good trade, if you ask me.
The Stevens AeroModel Edge 540 appealed to me the most
because it is much like many ARFs that are available. Silly, huh?
Why buy the kit if you can purchase the ARF?
Those “other” models are fine, but Bill engineered his Edge to be
an excellent performer in the precision and 3-D styles of flight. I
wouldn’t have to compromise laser-cutting technology that is found
in many ARFs to build the model myself, exactly as I wanted it to
be. Furthermore, this model would offer a personal look into the
evolution of design and construction techniques.
This Edge incorporates much of what laser cutting has brought to
the production of current models in weight savings and strength
techniques. With its provided full-size plans and clearly written and
04sig2.QXD 2/24/09 10:01 AM Page 60
April 2009 61
+•
Comes as complete laser-cut kit with all necessary
hardware.
• All-wood airframe construction with laser etching for
added accuracy.
• Tab-lock construction for a strong airframe and
components that build according to plan.
• Exceptionally well-written and illustrated instruction
manual includes flight instruction and total setup
requirements.
• Recommended motor system leaves nothing to be
desired by Unlimited and 3-D pilots.
• Edge 540’s practical size is stable enough for the
intermediate RC pilot.
• Model is easy enough to build for the first-time
modeler.
• Entire construction process requires only one .5-ounce
bottle of thin cyanoacrylate.
-•
LE sheeting joint is fragile.
• Two-piece ABS cowling. (Fiberglass would be heavier,
though.)
Pluses and Minuses
Model type: RC Scale Unlimited 3-D kit
Skill level: Beginner builder, intermediate pilot
Wingspan: 50 inches
Wing area: 440 square inches
Length: 45 inches
Weight: 28-32 ounces
Wing loading: 9.8 ounces/square foot
Power (recommended): 350-watt system
Radio: Four channels (minimum), four miniservos
Construction: Balsa, light plywood, ABS cowl, clear
canopy
Covering/finish: Iron-on film (So-Lite recommended)
Price: $147.99
Motor: Hacker A30-16M (1060 Kv)
Speed control: Hacker X-40
Battery: 3S Thunder Power Extreme 2070 mAh
Propeller: APC 12 x 6E
Motor current: Highest draw 32 amps
Motor voltage: 10.4 under load
Motor output: 354 watts
Radio system: JR 6102 transmitter, JR R610UL
receiver, JR Sport SM22 miniservos, two 6-inch servo
extensions
Finish: Navy, red, white, and transparent yellow So-Lite;
matching Rust-Oleum paint
Weight: 38.8 ounces (33.9 ounces without battery)
Flight duration: Five to eight minutes
Specifications and Test-Model Details
The wing panels are supported with a carbon-fiber tube. The fit is
tight, so no sheath is needed. Sheeting joinery is tabbed.
Joint fits are tight. Parts lock into tabs, to assure a square
structure. The latest kits include carbon-fiber reinforcement for
elevator and rudder.
Photos by the author and Mark Lanterman
The Edge is covered before final
installation of the tail pieces. Servo
locations promote linkage setups
that are stiff and slop-free.
illustrated instruction and flight manual, the model is not only easy
to complete, but it is also well built, requires minimal experience,
and doesn’t call for elaborate tools from the builder.
The wood parts use tab-lock construction. When glued into place,
very little carving or fancy sanding is required to complete the
airframe’s finished shape. The Edge is built primarily with 1/16 and
1/8 balsa and 1mm and 3mm plywood. To keep weight down, only
where stress is expected to be high is plywood employed.
The clear canopy is vacuum-formed and fits neatly, with a
flanged front that offers plenty of gluing area. The cowling is two
pieces of vacuum-formed ABS plastic that require careful trimming
and fitting, since the material is purposefully thin and flexible. The
04sig2.QXD 2/24/09 10:01 AM Page 61
builder has the option of dressing the prebent music-wire landing gear
with scrap-balsa fairings. (It’s a nice finishing touch.)
I take back the comment about carving and shaping. The wheel
pants are made from 1/4 balsa layers that include 1mm and 3mm
plywood reinforcement. So you might be able to build the model on the
dining room table and not get yelled at; the wheel pants, on the other
hand, need to be taken out to the porch for shaping. It makes a mess.
When finished, these wheel pants are close to indestructible. I guess
the satisfaction of the result was so gratifying that I forgot about the
small amount of work it took to make them look nice. Covering them
with matching So-Lite wasn’t difficult either.
The equipment I chose for the project mostly consists of items
offered on Stevens AeroModel’s Web site. You can purchase
everything you need for this model from one source.
I used my JR 6102 transmitter and JR Sport servos, since I had
them on hand and they matched the specifications. But the power
system is exactly what Bill recommends and designed the model
around.
The Hacker A30-16M is a beautiful motor. I went with the
matching Hacker X-40 brushless controller, even though the system
was expected to pull only 30 amps. I found this system to be every bit
as good as other reviews have claimed it is.
For such a small package, I have yet to find a setup that is as
capable—or as quiet. And, quite frankly, a 175-watt-per-pound
airplane was an experience I didn’t want to pass up. That kind of highend
performance is often too expensive and/or impractical. This is a
small model with a big attitude.
Construction: Only the parts needed for the specific assembly are
removed from the wood sheets, which keeps everything
organized. All of the components are laser cut and fit exactly; no
fiddling is necessary.
The tail surfaces are built first, which is a perfect catalyst for
getting those
building brain cells
activated. When
completed, those flat
frame pieces are 1/8-
inch-thick, with
1mm plywood
laminated over the
joiner-wire stress
points.
Being familiar
with typical stickand-
sheet
construction (the
labor of), when the
tail was assembled
without glue, as
recommended, I was
62 MODEL AVIATION
The LE sheeting tab-locks to the ribs, ensuring airfoil shape and
rib alignment. JR Sport SM22 servos are used throughout, with
Du-Bro heavy-duty servo arms.
A 3S 2100-2500 mAh Li-Poly battery straps to a long plywood tray
that will accommodate almost any CG preference.
Underneath the large cowling is the recommended Hacker A30-16
motor and X-40 speed control. The anodized Tru-Turn spinner for
electrics promotes cooling and smooth operation.
Inverted flight requires a tiny amount of
forward stick pressure to maintain heading.
Precision aerobatics potential is almost
unlimited.
The Stevens Edge can fly from short grass as well as pavement.
Landings can be slowed to an airspeed that resembles a crawl.
04sig2.QXD 2/24/09 10:01 AM Page 62
able to pick up the assembly from the fullsize
plans sheet and handle it almost as if it
were all glued together. I have to admit that
this made me giggle; the security of the parts
led to premonitions of a fun and successful
build project—and a short one at that.
The laser cut leaves a beveled edge,
which is accounted for by the engineer. The
correct orientation of the parts will produce
a tight glue joint on both sides of the
assembly. Thin cyanoacrylate is the best
glue for securing the joints—all the parts,
actually. Dry-fitting is good for confirming
the accuracy of alignment before joinery is
made permanent.
Provided with my kit as a gift (maybe
everyone gets one) was a Sanding Block
Dual Grit 60/100. Its semisoft inner material
allows the user to easily hold the tool and
quickly rough out round LEs and bevel
hinge areas. Later I wrapped the block with
220- and 400-grit paper for finish-sanding.
The fuselage takes shape from the
bottom up, starting with constructing the
lower frame. This assembly includes the
magnetically secured battery hatch. Only
two magnets (don’t get the polarity wrong)
are included, but you have the option of
securing the wing panels with magnets as
well. Slick.
The laser-cut holes in the parts for the
magnet are basically a “snap-tight” fit.
Again, this part-fit phenomenon assures the
builder; there is little opportunity for the
sometimes delicate framework to go
crooked, although it did happen once.
I got a little forceful while attaching the
wing-root sheeting on the left wing panel.
My excessive pressure warped the TE
downward, which was obvious after
following the laser-etched hinge lines that
pointed straight to my blunder, which was
corrected.
The front half of the fuselage includes a
light-plywood box that carries the stress
loads of the power system, landing gear, and
wing spar. All of the fuselage subassemblies
build off of that inner frame.
Besides being cut accurately, the cool
thing about the forward and aft turtledeck
sheeting is the laser-etched kerf cuts that
allow the material to wrap around without
requiring a time-consuming molding
technique.
The build was fun, almost like plug-andplay.
When a part was needed, I plugged it
onto the tab-lock location and moved
forward. I found it helpful to use a long
glue-tip extender on the bottle of thin
cyanoacrylate to precisely apply the
adhesive. Overapplying glue can be a major
weight-gain point.
The wings are built and installed as a
two-piece system. Each half plugs into a
carbon-fiber tube that fits inside a lightplywood
box within the fuselage. The fit is
tight on the carbon-fiber tube, making
removal of the wings difficult.
I soaped the tube for easier installation
and secured each wing half with a 6-32
thumbscrew through the root—not an
optional magnet. I can change my mind
later.
The motor box is mounted to the
fuselage with 4-40 socket-head screws. The
box itself also locks in the music-wire
landing gear. Saturate the plywood gearstrut
channel with lots of thin cyanoacrylate.
This will ensure that the bangs and bumps of
rough-field flying won’t loosen their
satisfyingly tight fit.
Even the wing LE sheeting is tabbed
onto the ribs; it’s a beautiful thing! The one
part I didn’t like (and it’s about the only
thing) is that the sheeting on my kit was too
short at the LE to be sanded flush with the
ribs.
This means that only the top corner of
the LE cap touches the sheeting. Maybe I
sanded too much, but I had to resecure the
sheeting several times while blending in the
LE shape. The easy fix would be to add a
1/16-inch square strip to the sheeting and
sand the area flush.
Carbon-fiber strips on the TEs of the
ailerons, elevator, and rudder keep those
surfaces from warping—during the build
and while covering. The ailerons themselves
are works of art; the hinge area is built up—
not a solid, thick piece of balsa that needs to
be carved and sanded to a beveled edge; the
bevel is built in. (Happy sigh.)
The kit supplies all hardware needed to
complete the Edge. These pieces are a
mixture of laser-cut and Du-Bro parts that
accurately attach at the locations that laser
etching pinpoints. Use extremely light coats
of Bondo glazing putty to smooth the joint
on the cowling; the joint is in the scale
location, so filling is an option—not
required.
The airframe is plenty strong without
covering, so lightweight heat-shrink film
such as So-Lite works well. With the threeview
provided in the manual, an original
color scheme that looks sporty yet shows off
the model’s elegant framework was
accomplished.
I have transparent covering on the
bottom and white covering the upper areas
and fuselage. I found So-Lite to be a delight
to use, even though its properties are more
delicate than those of the robust MonoKote
and standard UltraCote, the use of which
would weight down this airplane.
I layered the navy and red onto the white
using the Windex method, but applying the
same colors over the transparent yellow
required heat to activate their adhesives.
Maybe the transparent colors have a surface
tack-proof coating.
So-Lite is incredibly pliable and will tack
back onto itself with just the heat from the
builder’s skin or breath, so be careful. I was
able to cover each balsa wheel pant in two
pieces; the seam runs down the center, front
to back. My sock-covered iron at 220°
helped me pull and tug the covering around,
free of wrinkles.
The ready-made servo openings in the
wings and tail area were the perfect fit for
my JR Sport SM22 servos. I installed Du-
Bro’s extra-strength servo arms to get the
needed throws for 3-D control and E/Z
Connectors on the short metal pushrods.
For fun, I programmed the ailerons into
the Flaperon function of the JR6102
transmitter so I can play with flaps or spoiler
functions later.
Flying the Edge: This 25-size model’s
ground handling is pretty good in short grass,
and the wide-stance undercarriage offers lots
of propeller clearance. I chose a Thunder
Power 18C 2070 mAh 3S Li-Poly pack to fuel
the Hacker motor system. To balance, the
battery mounts close to the CG; this means I
can experiment with different packs.
I measured the output by throttling up the
assembled aircraft and holding on for dear
life. Quite confidently, I could hold the
model in almost any attitude, let go at full
throttle, and it would fly up out of sight.
ROG (rise-off-ground) takeoffs at half
throttle are graceful yet still short, especially
with a mild headwind.
I’ve tested the Edge in conditions gusting
at 20 mph; although it gets tossed around, it
never let me feel out of control. It’s a blast
to fly in wind, actually.
I haven’t needed to play with CG points,
because from the first flight the Edge
handled neutrally in both upright and
inverted attitudes. The built-in engine thrust
benefits the model when power is applied
suddenly; however, the generous rudder area
compensates to an almost infinite amount.
I’ve programmed the dual rate functions
so that high rate can move the surfaces to
the limits but has 60%-70% exponential
(expo) to soften the input at the center of the
stick. Low rate control is 50% of the high
rate and has 10%-30% expo again for the
same purpose. I have no trouble landing and
taking off on high rates with this setup, but
my confidence is high with more than 50
flights now on the model.
The Edge, with its straight-LE wing, is
well suited for 3-D and high-G turning.
Harrier, Parachute, and Elevator maneuvers
benefited from a small mount of spoiler
mixed into the elevator input; it canceled
most of the wing rocking.
There tends to be a slight wiggle in
heading at high speeds, which is why the
vertical fin is as tall as it is. Scale Aerobatics
look great when the airspeed is managed,
which means that full throttle is mostly used
for straight-up portions of aerobatics or
emergency purposes. Can you say, “Yeeha!”?
I’d Do It Again: Since the point at which the
Stevens AeroModel Edge was halfway built,
I’ve wanted to build another. The experience
is so positive and enjoyable that it has
empowered me to want to create and build
more on a regular basis. Maybe I’ll try Bill’s
RV-4 next, but the Edge’s performance has
me looking hard at his CAP 232.
I leave my Edge 540 assembled, since its
50-inch span fits easily in my Toyota
4Runner. My model came out slightly
heavier than specified, probably because of
my cowl paint job and servo hardware; there
might be an ounce to be saved there. Having
flown the model in and out of the specified
flight envelope, the slightly higher wing
loading isn’t at all upsetting.
I still can’t get over that this size
model weighs just a hair more than 2
pounds. The engineering and wood
choices have much to do with that, I
suppose. Back in the day when kits were
more popular, we were happy with a
model this size weighing sometimes
twice as much. If Bill Stevens’ models
were available then, I doubt we’d be such
an ARF dominated hobby/sport. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Stevens AeroModel
1528 S. Nevada Ave.
Colorado Springs CO 80905
(719) 387-4187
www.stevensaero.com
Items Used In Review:
JR radio system:
JR Radios
(800) 338-4639
www.jrradios.com
Thunder Power batteries:
Thunder Power RC
(702) 228-8883
www.thunderpowerrc.com
Hacker A30-16M motor:
Hacker Brushless Motors
(480) 726-7519
www.hackerbrushless.com
Other Printed Reviews:
No information available at time of
publication.
Edition: Model Aviation - 2009/04
Page Numbers: 60,61,62,64,65
60 MODEL AVIATION
MICHAEL RAMSEY
Plane Talk: Stevens AeroModel Edge 540 3D Kit
Below: The music-wire landing gear is
dressed with balsa fairings. The balsa
wheel pants are nearly
indestructible and
effortlessly covered
with So-Lite
film.
Left: The Edge excels in 3-D aerobatics,
thanks to its light wing loading and high
power-to-weight ratio. Building this
aircraft to be a tight machine is simple.
Above: The framed Edge 540 fuselage is
rigid even without covering. The fuselage
sheeting is etched on the inside to fit the
curves more easily.
A fun build that will
have ’em wowed
at the field
A STEVENS AEROMODEL project is a modern affirmation that
the rewards of constructing an airplane from a kit are alive and well.
This experience may also be considered solid proof that many of the
torturous tasks involved in building light and straight are a thing of
the past.
A skilled engineer and draftsman, Bill Stevens has produced an
RC kit line that is solely electric-power based. The models range in
size from those that are suitable for inside a school gym to those that
are fully 3-D-capable and suitable for the club field.
Although Bill’s packaging methods are minimalist (a plastic bag
for a kit container), the sweet filling is in the kit parts’ exquisitely
detailed engineering and production. It’s a good trade, if you ask me.
The Stevens AeroModel Edge 540 appealed to me the most
because it is much like many ARFs that are available. Silly, huh?
Why buy the kit if you can purchase the ARF?
Those “other” models are fine, but Bill engineered his Edge to be
an excellent performer in the precision and 3-D styles of flight. I
wouldn’t have to compromise laser-cutting technology that is found
in many ARFs to build the model myself, exactly as I wanted it to
be. Furthermore, this model would offer a personal look into the
evolution of design and construction techniques.
This Edge incorporates much of what laser cutting has brought to
the production of current models in weight savings and strength
techniques. With its provided full-size plans and clearly written and
04sig2.QXD 2/24/09 10:01 AM Page 60
April 2009 61
+•
Comes as complete laser-cut kit with all necessary
hardware.
• All-wood airframe construction with laser etching for
added accuracy.
• Tab-lock construction for a strong airframe and
components that build according to plan.
• Exceptionally well-written and illustrated instruction
manual includes flight instruction and total setup
requirements.
• Recommended motor system leaves nothing to be
desired by Unlimited and 3-D pilots.
• Edge 540’s practical size is stable enough for the
intermediate RC pilot.
• Model is easy enough to build for the first-time
modeler.
• Entire construction process requires only one .5-ounce
bottle of thin cyanoacrylate.
-•
LE sheeting joint is fragile.
• Two-piece ABS cowling. (Fiberglass would be heavier,
though.)
Pluses and Minuses
Model type: RC Scale Unlimited 3-D kit
Skill level: Beginner builder, intermediate pilot
Wingspan: 50 inches
Wing area: 440 square inches
Length: 45 inches
Weight: 28-32 ounces
Wing loading: 9.8 ounces/square foot
Power (recommended): 350-watt system
Radio: Four channels (minimum), four miniservos
Construction: Balsa, light plywood, ABS cowl, clear
canopy
Covering/finish: Iron-on film (So-Lite recommended)
Price: $147.99
Motor: Hacker A30-16M (1060 Kv)
Speed control: Hacker X-40
Battery: 3S Thunder Power Extreme 2070 mAh
Propeller: APC 12 x 6E
Motor current: Highest draw 32 amps
Motor voltage: 10.4 under load
Motor output: 354 watts
Radio system: JR 6102 transmitter, JR R610UL
receiver, JR Sport SM22 miniservos, two 6-inch servo
extensions
Finish: Navy, red, white, and transparent yellow So-Lite;
matching Rust-Oleum paint
Weight: 38.8 ounces (33.9 ounces without battery)
Flight duration: Five to eight minutes
Specifications and Test-Model Details
The wing panels are supported with a carbon-fiber tube. The fit is
tight, so no sheath is needed. Sheeting joinery is tabbed.
Joint fits are tight. Parts lock into tabs, to assure a square
structure. The latest kits include carbon-fiber reinforcement for
elevator and rudder.
Photos by the author and Mark Lanterman
The Edge is covered before final
installation of the tail pieces. Servo
locations promote linkage setups
that are stiff and slop-free.
illustrated instruction and flight manual, the model is not only easy
to complete, but it is also well built, requires minimal experience,
and doesn’t call for elaborate tools from the builder.
The wood parts use tab-lock construction. When glued into place,
very little carving or fancy sanding is required to complete the
airframe’s finished shape. The Edge is built primarily with 1/16 and
1/8 balsa and 1mm and 3mm plywood. To keep weight down, only
where stress is expected to be high is plywood employed.
The clear canopy is vacuum-formed and fits neatly, with a
flanged front that offers plenty of gluing area. The cowling is two
pieces of vacuum-formed ABS plastic that require careful trimming
and fitting, since the material is purposefully thin and flexible. The
04sig2.QXD 2/24/09 10:01 AM Page 61
builder has the option of dressing the prebent music-wire landing gear
with scrap-balsa fairings. (It’s a nice finishing touch.)
I take back the comment about carving and shaping. The wheel
pants are made from 1/4 balsa layers that include 1mm and 3mm
plywood reinforcement. So you might be able to build the model on the
dining room table and not get yelled at; the wheel pants, on the other
hand, need to be taken out to the porch for shaping. It makes a mess.
When finished, these wheel pants are close to indestructible. I guess
the satisfaction of the result was so gratifying that I forgot about the
small amount of work it took to make them look nice. Covering them
with matching So-Lite wasn’t difficult either.
The equipment I chose for the project mostly consists of items
offered on Stevens AeroModel’s Web site. You can purchase
everything you need for this model from one source.
I used my JR 6102 transmitter and JR Sport servos, since I had
them on hand and they matched the specifications. But the power
system is exactly what Bill recommends and designed the model
around.
The Hacker A30-16M is a beautiful motor. I went with the
matching Hacker X-40 brushless controller, even though the system
was expected to pull only 30 amps. I found this system to be every bit
as good as other reviews have claimed it is.
For such a small package, I have yet to find a setup that is as
capable—or as quiet. And, quite frankly, a 175-watt-per-pound
airplane was an experience I didn’t want to pass up. That kind of highend
performance is often too expensive and/or impractical. This is a
small model with a big attitude.
Construction: Only the parts needed for the specific assembly are
removed from the wood sheets, which keeps everything
organized. All of the components are laser cut and fit exactly; no
fiddling is necessary.
The tail surfaces are built first, which is a perfect catalyst for
getting those
building brain cells
activated. When
completed, those flat
frame pieces are 1/8-
inch-thick, with
1mm plywood
laminated over the
joiner-wire stress
points.
Being familiar
with typical stickand-
sheet
construction (the
labor of), when the
tail was assembled
without glue, as
recommended, I was
62 MODEL AVIATION
The LE sheeting tab-locks to the ribs, ensuring airfoil shape and
rib alignment. JR Sport SM22 servos are used throughout, with
Du-Bro heavy-duty servo arms.
A 3S 2100-2500 mAh Li-Poly battery straps to a long plywood tray
that will accommodate almost any CG preference.
Underneath the large cowling is the recommended Hacker A30-16
motor and X-40 speed control. The anodized Tru-Turn spinner for
electrics promotes cooling and smooth operation.
Inverted flight requires a tiny amount of
forward stick pressure to maintain heading.
Precision aerobatics potential is almost
unlimited.
The Stevens Edge can fly from short grass as well as pavement.
Landings can be slowed to an airspeed that resembles a crawl.
04sig2.QXD 2/24/09 10:01 AM Page 62
able to pick up the assembly from the fullsize
plans sheet and handle it almost as if it
were all glued together. I have to admit that
this made me giggle; the security of the parts
led to premonitions of a fun and successful
build project—and a short one at that.
The laser cut leaves a beveled edge,
which is accounted for by the engineer. The
correct orientation of the parts will produce
a tight glue joint on both sides of the
assembly. Thin cyanoacrylate is the best
glue for securing the joints—all the parts,
actually. Dry-fitting is good for confirming
the accuracy of alignment before joinery is
made permanent.
Provided with my kit as a gift (maybe
everyone gets one) was a Sanding Block
Dual Grit 60/100. Its semisoft inner material
allows the user to easily hold the tool and
quickly rough out round LEs and bevel
hinge areas. Later I wrapped the block with
220- and 400-grit paper for finish-sanding.
The fuselage takes shape from the
bottom up, starting with constructing the
lower frame. This assembly includes the
magnetically secured battery hatch. Only
two magnets (don’t get the polarity wrong)
are included, but you have the option of
securing the wing panels with magnets as
well. Slick.
The laser-cut holes in the parts for the
magnet are basically a “snap-tight” fit.
Again, this part-fit phenomenon assures the
builder; there is little opportunity for the
sometimes delicate framework to go
crooked, although it did happen once.
I got a little forceful while attaching the
wing-root sheeting on the left wing panel.
My excessive pressure warped the TE
downward, which was obvious after
following the laser-etched hinge lines that
pointed straight to my blunder, which was
corrected.
The front half of the fuselage includes a
light-plywood box that carries the stress
loads of the power system, landing gear, and
wing spar. All of the fuselage subassemblies
build off of that inner frame.
Besides being cut accurately, the cool
thing about the forward and aft turtledeck
sheeting is the laser-etched kerf cuts that
allow the material to wrap around without
requiring a time-consuming molding
technique.
The build was fun, almost like plug-andplay.
When a part was needed, I plugged it
onto the tab-lock location and moved
forward. I found it helpful to use a long
glue-tip extender on the bottle of thin
cyanoacrylate to precisely apply the
adhesive. Overapplying glue can be a major
weight-gain point.
The wings are built and installed as a
two-piece system. Each half plugs into a
carbon-fiber tube that fits inside a lightplywood
box within the fuselage. The fit is
tight on the carbon-fiber tube, making
removal of the wings difficult.
I soaped the tube for easier installation
and secured each wing half with a 6-32
thumbscrew through the root—not an
optional magnet. I can change my mind
later.
The motor box is mounted to the
fuselage with 4-40 socket-head screws. The
box itself also locks in the music-wire
landing gear. Saturate the plywood gearstrut
channel with lots of thin cyanoacrylate.
This will ensure that the bangs and bumps of
rough-field flying won’t loosen their
satisfyingly tight fit.
Even the wing LE sheeting is tabbed
onto the ribs; it’s a beautiful thing! The one
part I didn’t like (and it’s about the only
thing) is that the sheeting on my kit was too
short at the LE to be sanded flush with the
ribs.
This means that only the top corner of
the LE cap touches the sheeting. Maybe I
sanded too much, but I had to resecure the
sheeting several times while blending in the
LE shape. The easy fix would be to add a
1/16-inch square strip to the sheeting and
sand the area flush.
Carbon-fiber strips on the TEs of the
ailerons, elevator, and rudder keep those
surfaces from warping—during the build
and while covering. The ailerons themselves
are works of art; the hinge area is built up—
not a solid, thick piece of balsa that needs to
be carved and sanded to a beveled edge; the
bevel is built in. (Happy sigh.)
The kit supplies all hardware needed to
complete the Edge. These pieces are a
mixture of laser-cut and Du-Bro parts that
accurately attach at the locations that laser
etching pinpoints. Use extremely light coats
of Bondo glazing putty to smooth the joint
on the cowling; the joint is in the scale
location, so filling is an option—not
required.
The airframe is plenty strong without
covering, so lightweight heat-shrink film
such as So-Lite works well. With the threeview
provided in the manual, an original
color scheme that looks sporty yet shows off
the model’s elegant framework was
accomplished.
I have transparent covering on the
bottom and white covering the upper areas
and fuselage. I found So-Lite to be a delight
to use, even though its properties are more
delicate than those of the robust MonoKote
and standard UltraCote, the use of which
would weight down this airplane.
I layered the navy and red onto the white
using the Windex method, but applying the
same colors over the transparent yellow
required heat to activate their adhesives.
Maybe the transparent colors have a surface
tack-proof coating.
So-Lite is incredibly pliable and will tack
back onto itself with just the heat from the
builder’s skin or breath, so be careful. I was
able to cover each balsa wheel pant in two
pieces; the seam runs down the center, front
to back. My sock-covered iron at 220°
helped me pull and tug the covering around,
free of wrinkles.
The ready-made servo openings in the
wings and tail area were the perfect fit for
my JR Sport SM22 servos. I installed Du-
Bro’s extra-strength servo arms to get the
needed throws for 3-D control and E/Z
Connectors on the short metal pushrods.
For fun, I programmed the ailerons into
the Flaperon function of the JR6102
transmitter so I can play with flaps or spoiler
functions later.
Flying the Edge: This 25-size model’s
ground handling is pretty good in short grass,
and the wide-stance undercarriage offers lots
of propeller clearance. I chose a Thunder
Power 18C 2070 mAh 3S Li-Poly pack to fuel
the Hacker motor system. To balance, the
battery mounts close to the CG; this means I
can experiment with different packs.
I measured the output by throttling up the
assembled aircraft and holding on for dear
life. Quite confidently, I could hold the
model in almost any attitude, let go at full
throttle, and it would fly up out of sight.
ROG (rise-off-ground) takeoffs at half
throttle are graceful yet still short, especially
with a mild headwind.
I’ve tested the Edge in conditions gusting
at 20 mph; although it gets tossed around, it
never let me feel out of control. It’s a blast
to fly in wind, actually.
I haven’t needed to play with CG points,
because from the first flight the Edge
handled neutrally in both upright and
inverted attitudes. The built-in engine thrust
benefits the model when power is applied
suddenly; however, the generous rudder area
compensates to an almost infinite amount.
I’ve programmed the dual rate functions
so that high rate can move the surfaces to
the limits but has 60%-70% exponential
(expo) to soften the input at the center of the
stick. Low rate control is 50% of the high
rate and has 10%-30% expo again for the
same purpose. I have no trouble landing and
taking off on high rates with this setup, but
my confidence is high with more than 50
flights now on the model.
The Edge, with its straight-LE wing, is
well suited for 3-D and high-G turning.
Harrier, Parachute, and Elevator maneuvers
benefited from a small mount of spoiler
mixed into the elevator input; it canceled
most of the wing rocking.
There tends to be a slight wiggle in
heading at high speeds, which is why the
vertical fin is as tall as it is. Scale Aerobatics
look great when the airspeed is managed,
which means that full throttle is mostly used
for straight-up portions of aerobatics or
emergency purposes. Can you say, “Yeeha!”?
I’d Do It Again: Since the point at which the
Stevens AeroModel Edge was halfway built,
I’ve wanted to build another. The experience
is so positive and enjoyable that it has
empowered me to want to create and build
more on a regular basis. Maybe I’ll try Bill’s
RV-4 next, but the Edge’s performance has
me looking hard at his CAP 232.
I leave my Edge 540 assembled, since its
50-inch span fits easily in my Toyota
4Runner. My model came out slightly
heavier than specified, probably because of
my cowl paint job and servo hardware; there
might be an ounce to be saved there. Having
flown the model in and out of the specified
flight envelope, the slightly higher wing
loading isn’t at all upsetting.
I still can’t get over that this size
model weighs just a hair more than 2
pounds. The engineering and wood
choices have much to do with that, I
suppose. Back in the day when kits were
more popular, we were happy with a
model this size weighing sometimes
twice as much. If Bill Stevens’ models
were available then, I doubt we’d be such
an ARF dominated hobby/sport. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Stevens AeroModel
1528 S. Nevada Ave.
Colorado Springs CO 80905
(719) 387-4187
www.stevensaero.com
Items Used In Review:
JR radio system:
JR Radios
(800) 338-4639
www.jrradios.com
Thunder Power batteries:
Thunder Power RC
(702) 228-8883
www.thunderpowerrc.com
Hacker A30-16M motor:
Hacker Brushless Motors
(480) 726-7519
www.hackerbrushless.com
Other Printed Reviews:
No information available at time of
publication.
Edition: Model Aviation - 2009/04
Page Numbers: 60,61,62,64,65
60 MODEL AVIATION
MICHAEL RAMSEY
Plane Talk: Stevens AeroModel Edge 540 3D Kit
Below: The music-wire landing gear is
dressed with balsa fairings. The balsa
wheel pants are nearly
indestructible and
effortlessly covered
with So-Lite
film.
Left: The Edge excels in 3-D aerobatics,
thanks to its light wing loading and high
power-to-weight ratio. Building this
aircraft to be a tight machine is simple.
Above: The framed Edge 540 fuselage is
rigid even without covering. The fuselage
sheeting is etched on the inside to fit the
curves more easily.
A fun build that will
have ’em wowed
at the field
A STEVENS AEROMODEL project is a modern affirmation that
the rewards of constructing an airplane from a kit are alive and well.
This experience may also be considered solid proof that many of the
torturous tasks involved in building light and straight are a thing of
the past.
A skilled engineer and draftsman, Bill Stevens has produced an
RC kit line that is solely electric-power based. The models range in
size from those that are suitable for inside a school gym to those that
are fully 3-D-capable and suitable for the club field.
Although Bill’s packaging methods are minimalist (a plastic bag
for a kit container), the sweet filling is in the kit parts’ exquisitely
detailed engineering and production. It’s a good trade, if you ask me.
The Stevens AeroModel Edge 540 appealed to me the most
because it is much like many ARFs that are available. Silly, huh?
Why buy the kit if you can purchase the ARF?
Those “other” models are fine, but Bill engineered his Edge to be
an excellent performer in the precision and 3-D styles of flight. I
wouldn’t have to compromise laser-cutting technology that is found
in many ARFs to build the model myself, exactly as I wanted it to
be. Furthermore, this model would offer a personal look into the
evolution of design and construction techniques.
This Edge incorporates much of what laser cutting has brought to
the production of current models in weight savings and strength
techniques. With its provided full-size plans and clearly written and
04sig2.QXD 2/24/09 10:01 AM Page 60
April 2009 61
+•
Comes as complete laser-cut kit with all necessary
hardware.
• All-wood airframe construction with laser etching for
added accuracy.
• Tab-lock construction for a strong airframe and
components that build according to plan.
• Exceptionally well-written and illustrated instruction
manual includes flight instruction and total setup
requirements.
• Recommended motor system leaves nothing to be
desired by Unlimited and 3-D pilots.
• Edge 540’s practical size is stable enough for the
intermediate RC pilot.
• Model is easy enough to build for the first-time
modeler.
• Entire construction process requires only one .5-ounce
bottle of thin cyanoacrylate.
-•
LE sheeting joint is fragile.
• Two-piece ABS cowling. (Fiberglass would be heavier,
though.)
Pluses and Minuses
Model type: RC Scale Unlimited 3-D kit
Skill level: Beginner builder, intermediate pilot
Wingspan: 50 inches
Wing area: 440 square inches
Length: 45 inches
Weight: 28-32 ounces
Wing loading: 9.8 ounces/square foot
Power (recommended): 350-watt system
Radio: Four channels (minimum), four miniservos
Construction: Balsa, light plywood, ABS cowl, clear
canopy
Covering/finish: Iron-on film (So-Lite recommended)
Price: $147.99
Motor: Hacker A30-16M (1060 Kv)
Speed control: Hacker X-40
Battery: 3S Thunder Power Extreme 2070 mAh
Propeller: APC 12 x 6E
Motor current: Highest draw 32 amps
Motor voltage: 10.4 under load
Motor output: 354 watts
Radio system: JR 6102 transmitter, JR R610UL
receiver, JR Sport SM22 miniservos, two 6-inch servo
extensions
Finish: Navy, red, white, and transparent yellow So-Lite;
matching Rust-Oleum paint
Weight: 38.8 ounces (33.9 ounces without battery)
Flight duration: Five to eight minutes
Specifications and Test-Model Details
The wing panels are supported with a carbon-fiber tube. The fit is
tight, so no sheath is needed. Sheeting joinery is tabbed.
Joint fits are tight. Parts lock into tabs, to assure a square
structure. The latest kits include carbon-fiber reinforcement for
elevator and rudder.
Photos by the author and Mark Lanterman
The Edge is covered before final
installation of the tail pieces. Servo
locations promote linkage setups
that are stiff and slop-free.
illustrated instruction and flight manual, the model is not only easy
to complete, but it is also well built, requires minimal experience,
and doesn’t call for elaborate tools from the builder.
The wood parts use tab-lock construction. When glued into place,
very little carving or fancy sanding is required to complete the
airframe’s finished shape. The Edge is built primarily with 1/16 and
1/8 balsa and 1mm and 3mm plywood. To keep weight down, only
where stress is expected to be high is plywood employed.
The clear canopy is vacuum-formed and fits neatly, with a
flanged front that offers plenty of gluing area. The cowling is two
pieces of vacuum-formed ABS plastic that require careful trimming
and fitting, since the material is purposefully thin and flexible. The
04sig2.QXD 2/24/09 10:01 AM Page 61
builder has the option of dressing the prebent music-wire landing gear
with scrap-balsa fairings. (It’s a nice finishing touch.)
I take back the comment about carving and shaping. The wheel
pants are made from 1/4 balsa layers that include 1mm and 3mm
plywood reinforcement. So you might be able to build the model on the
dining room table and not get yelled at; the wheel pants, on the other
hand, need to be taken out to the porch for shaping. It makes a mess.
When finished, these wheel pants are close to indestructible. I guess
the satisfaction of the result was so gratifying that I forgot about the
small amount of work it took to make them look nice. Covering them
with matching So-Lite wasn’t difficult either.
The equipment I chose for the project mostly consists of items
offered on Stevens AeroModel’s Web site. You can purchase
everything you need for this model from one source.
I used my JR 6102 transmitter and JR Sport servos, since I had
them on hand and they matched the specifications. But the power
system is exactly what Bill recommends and designed the model
around.
The Hacker A30-16M is a beautiful motor. I went with the
matching Hacker X-40 brushless controller, even though the system
was expected to pull only 30 amps. I found this system to be every bit
as good as other reviews have claimed it is.
For such a small package, I have yet to find a setup that is as
capable—or as quiet. And, quite frankly, a 175-watt-per-pound
airplane was an experience I didn’t want to pass up. That kind of highend
performance is often too expensive and/or impractical. This is a
small model with a big attitude.
Construction: Only the parts needed for the specific assembly are
removed from the wood sheets, which keeps everything
organized. All of the components are laser cut and fit exactly; no
fiddling is necessary.
The tail surfaces are built first, which is a perfect catalyst for
getting those
building brain cells
activated. When
completed, those flat
frame pieces are 1/8-
inch-thick, with
1mm plywood
laminated over the
joiner-wire stress
points.
Being familiar
with typical stickand-
sheet
construction (the
labor of), when the
tail was assembled
without glue, as
recommended, I was
62 MODEL AVIATION
The LE sheeting tab-locks to the ribs, ensuring airfoil shape and
rib alignment. JR Sport SM22 servos are used throughout, with
Du-Bro heavy-duty servo arms.
A 3S 2100-2500 mAh Li-Poly battery straps to a long plywood tray
that will accommodate almost any CG preference.
Underneath the large cowling is the recommended Hacker A30-16
motor and X-40 speed control. The anodized Tru-Turn spinner for
electrics promotes cooling and smooth operation.
Inverted flight requires a tiny amount of
forward stick pressure to maintain heading.
Precision aerobatics potential is almost
unlimited.
The Stevens Edge can fly from short grass as well as pavement.
Landings can be slowed to an airspeed that resembles a crawl.
04sig2.QXD 2/24/09 10:01 AM Page 62
able to pick up the assembly from the fullsize
plans sheet and handle it almost as if it
were all glued together. I have to admit that
this made me giggle; the security of the parts
led to premonitions of a fun and successful
build project—and a short one at that.
The laser cut leaves a beveled edge,
which is accounted for by the engineer. The
correct orientation of the parts will produce
a tight glue joint on both sides of the
assembly. Thin cyanoacrylate is the best
glue for securing the joints—all the parts,
actually. Dry-fitting is good for confirming
the accuracy of alignment before joinery is
made permanent.
Provided with my kit as a gift (maybe
everyone gets one) was a Sanding Block
Dual Grit 60/100. Its semisoft inner material
allows the user to easily hold the tool and
quickly rough out round LEs and bevel
hinge areas. Later I wrapped the block with
220- and 400-grit paper for finish-sanding.
The fuselage takes shape from the
bottom up, starting with constructing the
lower frame. This assembly includes the
magnetically secured battery hatch. Only
two magnets (don’t get the polarity wrong)
are included, but you have the option of
securing the wing panels with magnets as
well. Slick.
The laser-cut holes in the parts for the
magnet are basically a “snap-tight” fit.
Again, this part-fit phenomenon assures the
builder; there is little opportunity for the
sometimes delicate framework to go
crooked, although it did happen once.
I got a little forceful while attaching the
wing-root sheeting on the left wing panel.
My excessive pressure warped the TE
downward, which was obvious after
following the laser-etched hinge lines that
pointed straight to my blunder, which was
corrected.
The front half of the fuselage includes a
light-plywood box that carries the stress
loads of the power system, landing gear, and
wing spar. All of the fuselage subassemblies
build off of that inner frame.
Besides being cut accurately, the cool
thing about the forward and aft turtledeck
sheeting is the laser-etched kerf cuts that
allow the material to wrap around without
requiring a time-consuming molding
technique.
The build was fun, almost like plug-andplay.
When a part was needed, I plugged it
onto the tab-lock location and moved
forward. I found it helpful to use a long
glue-tip extender on the bottle of thin
cyanoacrylate to precisely apply the
adhesive. Overapplying glue can be a major
weight-gain point.
The wings are built and installed as a
two-piece system. Each half plugs into a
carbon-fiber tube that fits inside a lightplywood
box within the fuselage. The fit is
tight on the carbon-fiber tube, making
removal of the wings difficult.
I soaped the tube for easier installation
and secured each wing half with a 6-32
thumbscrew through the root—not an
optional magnet. I can change my mind
later.
The motor box is mounted to the
fuselage with 4-40 socket-head screws. The
box itself also locks in the music-wire
landing gear. Saturate the plywood gearstrut
channel with lots of thin cyanoacrylate.
This will ensure that the bangs and bumps of
rough-field flying won’t loosen their
satisfyingly tight fit.
Even the wing LE sheeting is tabbed
onto the ribs; it’s a beautiful thing! The one
part I didn’t like (and it’s about the only
thing) is that the sheeting on my kit was too
short at the LE to be sanded flush with the
ribs.
This means that only the top corner of
the LE cap touches the sheeting. Maybe I
sanded too much, but I had to resecure the
sheeting several times while blending in the
LE shape. The easy fix would be to add a
1/16-inch square strip to the sheeting and
sand the area flush.
Carbon-fiber strips on the TEs of the
ailerons, elevator, and rudder keep those
surfaces from warping—during the build
and while covering. The ailerons themselves
are works of art; the hinge area is built up—
not a solid, thick piece of balsa that needs to
be carved and sanded to a beveled edge; the
bevel is built in. (Happy sigh.)
The kit supplies all hardware needed to
complete the Edge. These pieces are a
mixture of laser-cut and Du-Bro parts that
accurately attach at the locations that laser
etching pinpoints. Use extremely light coats
of Bondo glazing putty to smooth the joint
on the cowling; the joint is in the scale
location, so filling is an option—not
required.
The airframe is plenty strong without
covering, so lightweight heat-shrink film
such as So-Lite works well. With the threeview
provided in the manual, an original
color scheme that looks sporty yet shows off
the model’s elegant framework was
accomplished.
I have transparent covering on the
bottom and white covering the upper areas
and fuselage. I found So-Lite to be a delight
to use, even though its properties are more
delicate than those of the robust MonoKote
and standard UltraCote, the use of which
would weight down this airplane.
I layered the navy and red onto the white
using the Windex method, but applying the
same colors over the transparent yellow
required heat to activate their adhesives.
Maybe the transparent colors have a surface
tack-proof coating.
So-Lite is incredibly pliable and will tack
back onto itself with just the heat from the
builder’s skin or breath, so be careful. I was
able to cover each balsa wheel pant in two
pieces; the seam runs down the center, front
to back. My sock-covered iron at 220°
helped me pull and tug the covering around,
free of wrinkles.
The ready-made servo openings in the
wings and tail area were the perfect fit for
my JR Sport SM22 servos. I installed Du-
Bro’s extra-strength servo arms to get the
needed throws for 3-D control and E/Z
Connectors on the short metal pushrods.
For fun, I programmed the ailerons into
the Flaperon function of the JR6102
transmitter so I can play with flaps or spoiler
functions later.
Flying the Edge: This 25-size model’s
ground handling is pretty good in short grass,
and the wide-stance undercarriage offers lots
of propeller clearance. I chose a Thunder
Power 18C 2070 mAh 3S Li-Poly pack to fuel
the Hacker motor system. To balance, the
battery mounts close to the CG; this means I
can experiment with different packs.
I measured the output by throttling up the
assembled aircraft and holding on for dear
life. Quite confidently, I could hold the
model in almost any attitude, let go at full
throttle, and it would fly up out of sight.
ROG (rise-off-ground) takeoffs at half
throttle are graceful yet still short, especially
with a mild headwind.
I’ve tested the Edge in conditions gusting
at 20 mph; although it gets tossed around, it
never let me feel out of control. It’s a blast
to fly in wind, actually.
I haven’t needed to play with CG points,
because from the first flight the Edge
handled neutrally in both upright and
inverted attitudes. The built-in engine thrust
benefits the model when power is applied
suddenly; however, the generous rudder area
compensates to an almost infinite amount.
I’ve programmed the dual rate functions
so that high rate can move the surfaces to
the limits but has 60%-70% exponential
(expo) to soften the input at the center of the
stick. Low rate control is 50% of the high
rate and has 10%-30% expo again for the
same purpose. I have no trouble landing and
taking off on high rates with this setup, but
my confidence is high with more than 50
flights now on the model.
The Edge, with its straight-LE wing, is
well suited for 3-D and high-G turning.
Harrier, Parachute, and Elevator maneuvers
benefited from a small mount of spoiler
mixed into the elevator input; it canceled
most of the wing rocking.
There tends to be a slight wiggle in
heading at high speeds, which is why the
vertical fin is as tall as it is. Scale Aerobatics
look great when the airspeed is managed,
which means that full throttle is mostly used
for straight-up portions of aerobatics or
emergency purposes. Can you say, “Yeeha!”?
I’d Do It Again: Since the point at which the
Stevens AeroModel Edge was halfway built,
I’ve wanted to build another. The experience
is so positive and enjoyable that it has
empowered me to want to create and build
more on a regular basis. Maybe I’ll try Bill’s
RV-4 next, but the Edge’s performance has
me looking hard at his CAP 232.
I leave my Edge 540 assembled, since its
50-inch span fits easily in my Toyota
4Runner. My model came out slightly
heavier than specified, probably because of
my cowl paint job and servo hardware; there
might be an ounce to be saved there. Having
flown the model in and out of the specified
flight envelope, the slightly higher wing
loading isn’t at all upsetting.
I still can’t get over that this size
model weighs just a hair more than 2
pounds. The engineering and wood
choices have much to do with that, I
suppose. Back in the day when kits were
more popular, we were happy with a
model this size weighing sometimes
twice as much. If Bill Stevens’ models
were available then, I doubt we’d be such
an ARF dominated hobby/sport. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Stevens AeroModel
1528 S. Nevada Ave.
Colorado Springs CO 80905
(719) 387-4187
www.stevensaero.com
Items Used In Review:
JR radio system:
JR Radios
(800) 338-4639
www.jrradios.com
Thunder Power batteries:
Thunder Power RC
(702) 228-8883
www.thunderpowerrc.com
Hacker A30-16M motor:
Hacker Brushless Motors
(480) 726-7519
www.hackerbrushless.com
Other Printed Reviews:
No information available at time of
publication.
Edition: Model Aviation - 2009/04
Page Numbers: 60,61,62,64,65
60 MODEL AVIATION
MICHAEL RAMSEY
Plane Talk: Stevens AeroModel Edge 540 3D Kit
Below: The music-wire landing gear is
dressed with balsa fairings. The balsa
wheel pants are nearly
indestructible and
effortlessly covered
with So-Lite
film.
Left: The Edge excels in 3-D aerobatics,
thanks to its light wing loading and high
power-to-weight ratio. Building this
aircraft to be a tight machine is simple.
Above: The framed Edge 540 fuselage is
rigid even without covering. The fuselage
sheeting is etched on the inside to fit the
curves more easily.
A fun build that will
have ’em wowed
at the field
A STEVENS AEROMODEL project is a modern affirmation that
the rewards of constructing an airplane from a kit are alive and well.
This experience may also be considered solid proof that many of the
torturous tasks involved in building light and straight are a thing of
the past.
A skilled engineer and draftsman, Bill Stevens has produced an
RC kit line that is solely electric-power based. The models range in
size from those that are suitable for inside a school gym to those that
are fully 3-D-capable and suitable for the club field.
Although Bill’s packaging methods are minimalist (a plastic bag
for a kit container), the sweet filling is in the kit parts’ exquisitely
detailed engineering and production. It’s a good trade, if you ask me.
The Stevens AeroModel Edge 540 appealed to me the most
because it is much like many ARFs that are available. Silly, huh?
Why buy the kit if you can purchase the ARF?
Those “other” models are fine, but Bill engineered his Edge to be
an excellent performer in the precision and 3-D styles of flight. I
wouldn’t have to compromise laser-cutting technology that is found
in many ARFs to build the model myself, exactly as I wanted it to
be. Furthermore, this model would offer a personal look into the
evolution of design and construction techniques.
This Edge incorporates much of what laser cutting has brought to
the production of current models in weight savings and strength
techniques. With its provided full-size plans and clearly written and
04sig2.QXD 2/24/09 10:01 AM Page 60
April 2009 61
+•
Comes as complete laser-cut kit with all necessary
hardware.
• All-wood airframe construction with laser etching for
added accuracy.
• Tab-lock construction for a strong airframe and
components that build according to plan.
• Exceptionally well-written and illustrated instruction
manual includes flight instruction and total setup
requirements.
• Recommended motor system leaves nothing to be
desired by Unlimited and 3-D pilots.
• Edge 540’s practical size is stable enough for the
intermediate RC pilot.
• Model is easy enough to build for the first-time
modeler.
• Entire construction process requires only one .5-ounce
bottle of thin cyanoacrylate.
-•
LE sheeting joint is fragile.
• Two-piece ABS cowling. (Fiberglass would be heavier,
though.)
Pluses and Minuses
Model type: RC Scale Unlimited 3-D kit
Skill level: Beginner builder, intermediate pilot
Wingspan: 50 inches
Wing area: 440 square inches
Length: 45 inches
Weight: 28-32 ounces
Wing loading: 9.8 ounces/square foot
Power (recommended): 350-watt system
Radio: Four channels (minimum), four miniservos
Construction: Balsa, light plywood, ABS cowl, clear
canopy
Covering/finish: Iron-on film (So-Lite recommended)
Price: $147.99
Motor: Hacker A30-16M (1060 Kv)
Speed control: Hacker X-40
Battery: 3S Thunder Power Extreme 2070 mAh
Propeller: APC 12 x 6E
Motor current: Highest draw 32 amps
Motor voltage: 10.4 under load
Motor output: 354 watts
Radio system: JR 6102 transmitter, JR R610UL
receiver, JR Sport SM22 miniservos, two 6-inch servo
extensions
Finish: Navy, red, white, and transparent yellow So-Lite;
matching Rust-Oleum paint
Weight: 38.8 ounces (33.9 ounces without battery)
Flight duration: Five to eight minutes
Specifications and Test-Model Details
The wing panels are supported with a carbon-fiber tube. The fit is
tight, so no sheath is needed. Sheeting joinery is tabbed.
Joint fits are tight. Parts lock into tabs, to assure a square
structure. The latest kits include carbon-fiber reinforcement for
elevator and rudder.
Photos by the author and Mark Lanterman
The Edge is covered before final
installation of the tail pieces. Servo
locations promote linkage setups
that are stiff and slop-free.
illustrated instruction and flight manual, the model is not only easy
to complete, but it is also well built, requires minimal experience,
and doesn’t call for elaborate tools from the builder.
The wood parts use tab-lock construction. When glued into place,
very little carving or fancy sanding is required to complete the
airframe’s finished shape. The Edge is built primarily with 1/16 and
1/8 balsa and 1mm and 3mm plywood. To keep weight down, only
where stress is expected to be high is plywood employed.
The clear canopy is vacuum-formed and fits neatly, with a
flanged front that offers plenty of gluing area. The cowling is two
pieces of vacuum-formed ABS plastic that require careful trimming
and fitting, since the material is purposefully thin and flexible. The
04sig2.QXD 2/24/09 10:01 AM Page 61
builder has the option of dressing the prebent music-wire landing gear
with scrap-balsa fairings. (It’s a nice finishing touch.)
I take back the comment about carving and shaping. The wheel
pants are made from 1/4 balsa layers that include 1mm and 3mm
plywood reinforcement. So you might be able to build the model on the
dining room table and not get yelled at; the wheel pants, on the other
hand, need to be taken out to the porch for shaping. It makes a mess.
When finished, these wheel pants are close to indestructible. I guess
the satisfaction of the result was so gratifying that I forgot about the
small amount of work it took to make them look nice. Covering them
with matching So-Lite wasn’t difficult either.
The equipment I chose for the project mostly consists of items
offered on Stevens AeroModel’s Web site. You can purchase
everything you need for this model from one source.
I used my JR 6102 transmitter and JR Sport servos, since I had
them on hand and they matched the specifications. But the power
system is exactly what Bill recommends and designed the model
around.
The Hacker A30-16M is a beautiful motor. I went with the
matching Hacker X-40 brushless controller, even though the system
was expected to pull only 30 amps. I found this system to be every bit
as good as other reviews have claimed it is.
For such a small package, I have yet to find a setup that is as
capable—or as quiet. And, quite frankly, a 175-watt-per-pound
airplane was an experience I didn’t want to pass up. That kind of highend
performance is often too expensive and/or impractical. This is a
small model with a big attitude.
Construction: Only the parts needed for the specific assembly are
removed from the wood sheets, which keeps everything
organized. All of the components are laser cut and fit exactly; no
fiddling is necessary.
The tail surfaces are built first, which is a perfect catalyst for
getting those
building brain cells
activated. When
completed, those flat
frame pieces are 1/8-
inch-thick, with
1mm plywood
laminated over the
joiner-wire stress
points.
Being familiar
with typical stickand-
sheet
construction (the
labor of), when the
tail was assembled
without glue, as
recommended, I was
62 MODEL AVIATION
The LE sheeting tab-locks to the ribs, ensuring airfoil shape and
rib alignment. JR Sport SM22 servos are used throughout, with
Du-Bro heavy-duty servo arms.
A 3S 2100-2500 mAh Li-Poly battery straps to a long plywood tray
that will accommodate almost any CG preference.
Underneath the large cowling is the recommended Hacker A30-16
motor and X-40 speed control. The anodized Tru-Turn spinner for
electrics promotes cooling and smooth operation.
Inverted flight requires a tiny amount of
forward stick pressure to maintain heading.
Precision aerobatics potential is almost
unlimited.
The Stevens Edge can fly from short grass as well as pavement.
Landings can be slowed to an airspeed that resembles a crawl.
04sig2.QXD 2/24/09 10:01 AM Page 62
able to pick up the assembly from the fullsize
plans sheet and handle it almost as if it
were all glued together. I have to admit that
this made me giggle; the security of the parts
led to premonitions of a fun and successful
build project—and a short one at that.
The laser cut leaves a beveled edge,
which is accounted for by the engineer. The
correct orientation of the parts will produce
a tight glue joint on both sides of the
assembly. Thin cyanoacrylate is the best
glue for securing the joints—all the parts,
actually. Dry-fitting is good for confirming
the accuracy of alignment before joinery is
made permanent.
Provided with my kit as a gift (maybe
everyone gets one) was a Sanding Block
Dual Grit 60/100. Its semisoft inner material
allows the user to easily hold the tool and
quickly rough out round LEs and bevel
hinge areas. Later I wrapped the block with
220- and 400-grit paper for finish-sanding.
The fuselage takes shape from the
bottom up, starting with constructing the
lower frame. This assembly includes the
magnetically secured battery hatch. Only
two magnets (don’t get the polarity wrong)
are included, but you have the option of
securing the wing panels with magnets as
well. Slick.
The laser-cut holes in the parts for the
magnet are basically a “snap-tight” fit.
Again, this part-fit phenomenon assures the
builder; there is little opportunity for the
sometimes delicate framework to go
crooked, although it did happen once.
I got a little forceful while attaching the
wing-root sheeting on the left wing panel.
My excessive pressure warped the TE
downward, which was obvious after
following the laser-etched hinge lines that
pointed straight to my blunder, which was
corrected.
The front half of the fuselage includes a
light-plywood box that carries the stress
loads of the power system, landing gear, and
wing spar. All of the fuselage subassemblies
build off of that inner frame.
Besides being cut accurately, the cool
thing about the forward and aft turtledeck
sheeting is the laser-etched kerf cuts that
allow the material to wrap around without
requiring a time-consuming molding
technique.
The build was fun, almost like plug-andplay.
When a part was needed, I plugged it
onto the tab-lock location and moved
forward. I found it helpful to use a long
glue-tip extender on the bottle of thin
cyanoacrylate to precisely apply the
adhesive. Overapplying glue can be a major
weight-gain point.
The wings are built and installed as a
two-piece system. Each half plugs into a
carbon-fiber tube that fits inside a lightplywood
box within the fuselage. The fit is
tight on the carbon-fiber tube, making
removal of the wings difficult.
I soaped the tube for easier installation
and secured each wing half with a 6-32
thumbscrew through the root—not an
optional magnet. I can change my mind
later.
The motor box is mounted to the
fuselage with 4-40 socket-head screws. The
box itself also locks in the music-wire
landing gear. Saturate the plywood gearstrut
channel with lots of thin cyanoacrylate.
This will ensure that the bangs and bumps of
rough-field flying won’t loosen their
satisfyingly tight fit.
Even the wing LE sheeting is tabbed
onto the ribs; it’s a beautiful thing! The one
part I didn’t like (and it’s about the only
thing) is that the sheeting on my kit was too
short at the LE to be sanded flush with the
ribs.
This means that only the top corner of
the LE cap touches the sheeting. Maybe I
sanded too much, but I had to resecure the
sheeting several times while blending in the
LE shape. The easy fix would be to add a
1/16-inch square strip to the sheeting and
sand the area flush.
Carbon-fiber strips on the TEs of the
ailerons, elevator, and rudder keep those
surfaces from warping—during the build
and while covering. The ailerons themselves
are works of art; the hinge area is built up—
not a solid, thick piece of balsa that needs to
be carved and sanded to a beveled edge; the
bevel is built in. (Happy sigh.)
The kit supplies all hardware needed to
complete the Edge. These pieces are a
mixture of laser-cut and Du-Bro parts that
accurately attach at the locations that laser
etching pinpoints. Use extremely light coats
of Bondo glazing putty to smooth the joint
on the cowling; the joint is in the scale
location, so filling is an option—not
required.
The airframe is plenty strong without
covering, so lightweight heat-shrink film
such as So-Lite works well. With the threeview
provided in the manual, an original
color scheme that looks sporty yet shows off
the model’s elegant framework was
accomplished.
I have transparent covering on the
bottom and white covering the upper areas
and fuselage. I found So-Lite to be a delight
to use, even though its properties are more
delicate than those of the robust MonoKote
and standard UltraCote, the use of which
would weight down this airplane.
I layered the navy and red onto the white
using the Windex method, but applying the
same colors over the transparent yellow
required heat to activate their adhesives.
Maybe the transparent colors have a surface
tack-proof coating.
So-Lite is incredibly pliable and will tack
back onto itself with just the heat from the
builder’s skin or breath, so be careful. I was
able to cover each balsa wheel pant in two
pieces; the seam runs down the center, front
to back. My sock-covered iron at 220°
helped me pull and tug the covering around,
free of wrinkles.
The ready-made servo openings in the
wings and tail area were the perfect fit for
my JR Sport SM22 servos. I installed Du-
Bro’s extra-strength servo arms to get the
needed throws for 3-D control and E/Z
Connectors on the short metal pushrods.
For fun, I programmed the ailerons into
the Flaperon function of the JR6102
transmitter so I can play with flaps or spoiler
functions later.
Flying the Edge: This 25-size model’s
ground handling is pretty good in short grass,
and the wide-stance undercarriage offers lots
of propeller clearance. I chose a Thunder
Power 18C 2070 mAh 3S Li-Poly pack to fuel
the Hacker motor system. To balance, the
battery mounts close to the CG; this means I
can experiment with different packs.
I measured the output by throttling up the
assembled aircraft and holding on for dear
life. Quite confidently, I could hold the
model in almost any attitude, let go at full
throttle, and it would fly up out of sight.
ROG (rise-off-ground) takeoffs at half
throttle are graceful yet still short, especially
with a mild headwind.
I’ve tested the Edge in conditions gusting
at 20 mph; although it gets tossed around, it
never let me feel out of control. It’s a blast
to fly in wind, actually.
I haven’t needed to play with CG points,
because from the first flight the Edge
handled neutrally in both upright and
inverted attitudes. The built-in engine thrust
benefits the model when power is applied
suddenly; however, the generous rudder area
compensates to an almost infinite amount.
I’ve programmed the dual rate functions
so that high rate can move the surfaces to
the limits but has 60%-70% exponential
(expo) to soften the input at the center of the
stick. Low rate control is 50% of the high
rate and has 10%-30% expo again for the
same purpose. I have no trouble landing and
taking off on high rates with this setup, but
my confidence is high with more than 50
flights now on the model.
The Edge, with its straight-LE wing, is
well suited for 3-D and high-G turning.
Harrier, Parachute, and Elevator maneuvers
benefited from a small mount of spoiler
mixed into the elevator input; it canceled
most of the wing rocking.
There tends to be a slight wiggle in
heading at high speeds, which is why the
vertical fin is as tall as it is. Scale Aerobatics
look great when the airspeed is managed,
which means that full throttle is mostly used
for straight-up portions of aerobatics or
emergency purposes. Can you say, “Yeeha!”?
I’d Do It Again: Since the point at which the
Stevens AeroModel Edge was halfway built,
I’ve wanted to build another. The experience
is so positive and enjoyable that it has
empowered me to want to create and build
more on a regular basis. Maybe I’ll try Bill’s
RV-4 next, but the Edge’s performance has
me looking hard at his CAP 232.
I leave my Edge 540 assembled, since its
50-inch span fits easily in my Toyota
4Runner. My model came out slightly
heavier than specified, probably because of
my cowl paint job and servo hardware; there
might be an ounce to be saved there. Having
flown the model in and out of the specified
flight envelope, the slightly higher wing
loading isn’t at all upsetting.
I still can’t get over that this size
model weighs just a hair more than 2
pounds. The engineering and wood
choices have much to do with that, I
suppose. Back in the day when kits were
more popular, we were happy with a
model this size weighing sometimes
twice as much. If Bill Stevens’ models
were available then, I doubt we’d be such
an ARF dominated hobby/sport. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Stevens AeroModel
1528 S. Nevada Ave.
Colorado Springs CO 80905
(719) 387-4187
www.stevensaero.com
Items Used In Review:
JR radio system:
JR Radios
(800) 338-4639
www.jrradios.com
Thunder Power batteries:
Thunder Power RC
(702) 228-8883
www.thunderpowerrc.com
Hacker A30-16M motor:
Hacker Brushless Motors
(480) 726-7519
www.hackerbrushless.com
Other Printed Reviews:
No information available at time of
publication.