Product Review - 2004/04

P r o d u c t R e v i e w Mark Lanterman
5655 David Pl., Fairfield OH 45014; E-mail: [email protected]
Sig 1/5-Scale Piper J-3 Cub
Pros:
• Nicely illustrated manual.
• Laser-cut pieces.
• Well-thought-out assembly and all
pieces lock into position before gluing.
• Working side door/window makes it
easy to plug in servos, hide switches
and a remote glow driver, etc. without
removing the wing.
• Two-piece, plug-in wings make
transporting simple.
• Great flying characteristics.
Cons:
• The instruction manual has a couple
of typos.
• The window does not lock in place
with the door-latch mechanism. (See
text.)
The author chose a Swiss Cub’s color scheme. From this angle you could almost mistake it for full scale.
When you couple the Cub’s flying characteristics with the realistic sound of a fourstroke
engine, you end up with a great Scale model.
EVERYBODY LOVES a Cub—or is that a
clown? I guess it depends on whom you ask;
they’re probably interchangeable. One thing
is for sure, though: Mr. Piper’s J-3 Cub is
one of the most-modeled, -flown, and -loved
designs in Radio Control. It is one of the few
designs that flies as well in model form as it
does in full-scale form.
Being the advertising representative for
Model Aviation, normally my only
involvement in product reviews is to help set
them up and lend a hand with the
photography. But when Sig’s 1⁄5-scale kit
arrived for initial photography, I talked
Aeromodeling Editor Bob Hunt into letting
me take a stab at reviewing it.
First Impressions: The first thing I noticed
when I opened the box was that this was a
ready-to-assemble kit. There was a fair
amount of wood, three rolled sheets of fullsize
plans, several bags of hardware, some
vacuum-formed white ABS parts, clear
vacuum-formed windows, and a fiberglass
cowl.
Luckily, a nicely illustrated instruction
manual was included to tell me how to put
all those pieces together. The front of the
manual had diagrams showing all the lasercut
pieces’ names. Before getting too far into
things, be sure to label each of these parts
before they fall out. Doing so now can save a
great deal of time later!
Construction: A kit usually starts with
building the fuselage or the wings. Not so
with the Cub. In this case you start with a
few subassemblies, one of which is
mounting the engine on the firewall. I was a
bit skeptical about doing this step so early in
construction, but as you’ll see later, the
people at Sig know what they’re doing.
84 MODEL AVIATION
April 2004 85
Sig’s 1⁄5-scale Cub comes as a ready-to-assemble kit. There is a fair amount of parts, but
all pieces are high quality and everything goes together quickly.
The airframe is complete, sanded, and ready for covering. Spending a couple hours a
night, it took approximately a week to get to this point.
Flying almost any Cub is relaxing. With the recommended
throws, this model is a smooth flier and a gentle barnstormer.
Caught right after takeoff on maiden flight, the Cub flew great,
needing slight right rudder trim for hands-off flight.
I chose one of the RCV .56 engines to
power my Cub. This engine proved to be a
nice, compact size that fit into the cowl
without additional cutouts. I mated the
engine with a Performance Specialties fourstroke
muffler and a 90° adapter, which put
the exhaust out the bottom of the cowl.
Another step that seemed premature was
building the fuselage’s servo tray and
mounting the throttle, rudder, and elevator
servos. Those things are not normally done
until much later, but Sig says to do it so I
did.
Other subassemblies included
premounting blind nuts for the tail wheel and
wing struts and gluing in plywood pieces to
strengthen the fuselage sides.
Wing: After the subassemblies, you start on
the wings. This Cub’s design features a twopiece,
plug-in wing system, so each half is
built separately. There’s nothing tricky
here—average rib and spar construction.
Because of the accurate laser-cutting,
everything locks into place nicely and
there’s no need for sanding. In just a few
minutes an entire wing panel can be laid out
and ready for gluing.
Once everything has been trued up and
glued into position, you apply sheeting to the
leading edge and the inboard section.
Capstrips and sheeting around the aileron
area are also applied at this time.
Flipping the wing over, you apply
additional sheeting to the leading edge and
inboard section. You glue in four of the
preassemblies making up the strut mounts,
and then capstrips finish off the bottom.
After you have glued in the tip pieces, the
wing half is finished and ready for sanding.
The interlocking construction makes a wing
that is strong and quite resistant to flexing.
After repeating the steps for the other wing,
build the ailerons. Using a number of
formers, which fit into precut top and bottom
sheeting, the ailerons come out much lighter
than solid balsa would.
Tail Surfaces: The fin, stabilizer, rudder,
and elevator halves are of simple,
straightforward construction. As you’ll see
later, the tail surfaces are all braced. Where
Photos by the author
the attachment points are, you cut dowels to
length and insert them into precut holes. This
makes for a much stronger attachment point
than balsa would.
Fuselage: Putting the fuselage together is
similar to the wing, in that all parts are dryassembled
and then glued into a single piece.
The design is somewhat typical because there
are slab sides with formers in between.
However, Sig put in a few neat things.
Many kits that utilize slab sides for the
fuselage simply use two pieces of plywood for
the sides. Although it’s strong, the plywood
makes for extra sanding, and covering
plywood with iron-on film can be difficult.
This Cub goes a step beyond; the plywood’s
outer surfaces are covered with thin balsa
sheeting, which is laser-cut to match the
plywood exactly. It’s easy to sand and a breeze
to cover.
The formers’ interlocking design, along
with the laser-cutting, makes everything fit
well. You literally build the fuselage in your
hands—no pinning it to a board. Even so, after
everything is clamped or taped together, the
alignment is straight and true. Well done, Sig!
Adding to the Cub’s scale look is a series
of stringers that are glued over the slab sides.
You’ll need to do a bit of trimming and
sanding to get the stringers to the right size and
shape, but the effort is well worth it when the
model is covered.
The other features that set this Cub apart
from the previous Sig kits are the functional
door and window on the starboard side.
Although some time is needed to ensure that
everything is properly aligned, it works well.
However, I still don’t understand why only
the bottom portion of the door is held in with
the latch mechanism. It’s true that the airflow
will keep the window portion of the door
closed, but having the door’s upper edge
overlap the window (instead of the other way
around) would lock everything in place. Oh
well. I guess Sig has its reasons.
Landing Gear: The stock landing gear
included with the kit will work fine. It is rigid
but requires soldering and a bit of work. I
decided to use the Robart Cub gear. The
Robart design incorporates a functional shockabsorbing
system similar to that of the fullscale
Cub. It comes ready to assemble and
takes approximately five minutes to put
together.
If you use the Robart gear, mounting is
different. Sig’s gear is pressed into grooved
hardwood blocks and held in place with gear
straps. Robart’s system requires you to drill
holes to bolt the gear directly to the fuselage
belly. A drilling template is provided, which
makes this easy. If you line it up correctly, you
can drill into the hardwood blocks and still use
them by using blind nuts from the inside.
Oh, and if you decide to use the Robart
gear, flip the hardwood landing-gear blocks
over before gluing in place. This puts the
smooth surface on the outside.
The gear itself is manufactured from 4130
tubular steel frames that are welded together.
The pivot pins and mounting screws are
hardened and plated. All pieces are held
together with c-clips and hex bolts with lock
nuts.
After everything was mounted and working
properly, I removed the pieces. I had to come
up with a “filler” to cover the port and
starboard frames. For this I epoxied thin
styrene sheeting to the frames, and then I
painted all the pieces to match the airplane’s
color scheme.
Once assembled, the rubber bungees give a
nice amount of flex. The gear is firm enough
not to give while taxiing, but it provides just
the right amount of flex to take the bounce out
of harder landings.
Final Assembly: After all the major pieces
were finished, I made the port and starboard
struts to support the wings. I constructed those
struts from hardwood pieces which were
trimmed and glued into a “V” shape, and then
I slotted the ends to accept aluminum
mounting brackets.
The midpoint of the struts require you to
cut and form smaller “jury” support struts from
the supplied brass tubing. This is probably one
of the longer steps because once all the precise
fitting is finished, you should sand the
hardwood to a more aerodynamic shape. The
plans include full-size drawings of all the
struts, including bending angles and drilling
guides, making all this much easier.
After thoroughly sanding the entire
airframe, I covered the Cub with Coverite’s
21st Century fabric covering. Since I also had
plans to try my hand at Scale competition, I
copied the color scheme of a full-scale Cub. I
chose it because the white and blue with red
trim stands out compared to the more typical
Cub schemes.
With covering completed, the tail struts are
next. You make them by cutting the supplied,
threaded rod to length and soldering a
modified clevis to one end while threading
another modified clevis to the other end. After
all four struts are made and adjusted to the
proper length, attach them.
Trim the windows and glue them into
position. There’s nothing tricky here, but the
front windshield will require a bit of trial-anderror
trimming so it will clear the leading edge
of the wings.
The cowl is one piece and made from
fiberglass. It has no holes at all, so you have to
do all the work yourself. Take your time when
doing this; you don’t want holes to be larger
than needed—or worse, in the wrong place.
The manual shows where the holes should be,
but you’ll have to do the measuring.
To finish the cowl’s scale look there are
vacuum-formed ABS dummy engine halves.
These need to be trimmed to fit. Although
they’re not extremely detailed, once attached
and painted they add a bit of realism when
viewed from a few feet away.
All the control hookups are
straightforward, consisting of flexible
pushrods for the elevator and throttle. I found
the need to add a few small, plywood brackets
made from scrap along the length of the
throttle pushrod to keep it from flexing.
A pull-pull system is used on the rudder
and can take some time to install. The system
itself works fine, but it is difficult to thread the
thin wire through the covered fuselage and not
have it get caught on formers or find its way
between the fuselage sides and the covering.
While I was finishing up these details, I
realized why Sig instructs builders to mount
the engine and the servos right away. It would
be almost impossible to get to the back of the
firewall and tough to mount the servos once
the fuselage was assembled. As always, it’s
good to follow the instructions—even if things
look out of order.
With everything completed, the Cub
balanced as it should have. Not bad
considering the extra weight of the fabric
covering, a larger 1100 mAh battery (for long
flying days), the Robart gear, and the Du-Bro
wheels. The final weight—ready to fly in scale
trim—was 8 pounds.
Flying: No matter how many kits I build, I
still get “butterflies” on every maiden flight.
This time was even more so since I’d put more
than the usual time in this Cub.
Assembling the Cub at the field takes
roughly five minutes. You slide each wing half
into position with an aluminum tube riding
snugly in the installed phenolic tube. A 10-32
bolt holds the wing in place while the strut is
attached. Each wing strut requires five 4-40
screws to hold it in position.
Once the wings are on, you install the top
hatch with two more 4-40 screws. This hatch
doubles as a limiter for the aluminum wing
tubes. (Be sure to pack a few extra screws,
washers, and lock nuts; you never know when
you’ll drop one!)
The functional door is a great idea; it gives
you good access to plug in the aileron servos
with the wing and struts attached. I also took
advantage of this to hide the radio’s switch and
a remote glow plug in the cockpit area.
After assembly and a quick preflight check,
I was ready to go. I started the engine and let it
warm up, and then I started to taxi the Cub.
After approximately 30 seconds of running
time, the engine quit. When I went back to the
pits to restart the engine, it wouldn’t fire no
matter what I did. Grumble, grumble, and back
home for the day.
At home I removed the engine and tried
restarting it on my test bench. It wouldn’t fire.
I threw everything at it: new plugs, different
fuel tanks, the works. Frustrated, I decided to
solve the problem with a radical solution: I
switched to a different engine. I had a Saito 56,
and it fit with a few changes and several more
cutouts in the cowl.
With the engine problem resolved, I was
off for the first flight. The Cub lifted off as it
should and required just a bit of right rudder
trim. Using the suggested throws, it flew
nicely and did everything I asked it to do. Mild
aerobatics—loops, barrel rolls, stall turns, and
the like—-were scalelike. This model doesn’t
do much more than that, but the full-scale Cub
doesn’t do much more either.
Under low power settings the model
88 MODEL AVIATION
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San Francisco CA
“
”
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slowed nicely and remained responsive, even
when close to stall speed. Good, bounce-free
landings can be performed routinely—
probably because of the Robart bungee
system.
As you can probably tell, I am having a
blast flying the Cub. It has a great scale
presence in the air and makes for a nice
barnstormer. Since the maiden flight I have
logged a ton of time with the Cub, practicing
Scale maneuvers for competition. I entered it
in Fun Scale at last year’s Nationals.
Sig has a winner on its hands with this Cub.
It’s quick and fun to build and flies just like
you would expect a Cub to fly. Paired with a
four-stroke engine in the 56-61 range, it will
have all the power it needs with a fantastic
scale sound. If you’re a Radio Control pilot
but have never tried your hand at building a
kit, this is a great choice. MA
(Editor’s note: It is our policy to send a
copy of each review to the manufacturer
whose product is being evaluated. Sig
Manufacturing responded to a couple
comments the author made in the “Cons”
section of this review.
First, Sig wanted readers to know that the
typos in the instruction booklet have been
corrected.
Second, the company pointed out that
the upper side door does not have a
retainer because in actual practice it does
not need retention; it is held firmly in
place under compression with the top side
of the lower hinged door.
Sig informed us that after flying several of
these models in the past two years, both
hinged doors stayed firmly closed unless the
modeler purposely opened them for radio
access. In short, they were designed that
way.)
Specifications:
Wingspan: 84.5 inches
Wing area: 947 square inches
Length: 55.25 inches
Model weight recommended: 7-7.5 pounds
Review model’s weight (ready to fly): 8
pounds (with items added for Scale
competition)
Engine recommended: .40-.46 two-stroke or
45-65 four-stroke
Engine used: Saito 56 four-stroke
Radio recommended: four-channel with five
servos
Radio used: JR 8103 transmitter, JR R700
receiver, five Expert SL571 servos, JR Extra
1100 mAh battery
Materials used in construction: balsa,
plywood, fiberglass (cowl)
Street Price: $129
Manufacturer/distributor:
Sig Manufacturing
Box 520
Montezuma IA 50171
(641) 623-5154
www.sigmfg.com
Products used:
JR 8103 radio system, Saito 56 engine, 1⁄5-
scale civilian pilot:
Horizon Hobby Distributors
4105 Fieldstone Rd.
Champaign IL 61822
(217) 352-1913
www.horizonhobby.com
1⁄5th-scale Cub gear:
Robart Manufacturing, Inc.
625 N. 12th St.
Saint Charles IL 60174
(630) 584-7616
www.robart.com
Fill-It Fueling System, 1⁄5-scale Cub wheels:
Du-Bro Products
Box 815
Wauconda IL 60084
(847) 526-2136
www.dubro.com
Master Airscrew 12 x 6 two-blade propeller:
Windsor Propeller Co., Inc.
Box 250
Rancho Cordova CA 95741
www.masterairscrew.com
10-ounce fuel tank:
Sullivan Products
1 North Haven St.
Baltimore MD 21224
(410) 732-3500
www.sullivanproducts.com
90 MODEL AVIATION

P r o d u c t R e v i e w Mark Lanterman
5655 David Pl., Fairfield OH 45014; E-mail: [email protected]
Sig 1/5-Scale Piper J-3 Cub
Pros:
• Nicely illustrated manual.
• Laser-cut pieces.
• Well-thought-out assembly and all
pieces lock into position before gluing.
• Working side door/window makes it
easy to plug in servos, hide switches
and a remote glow driver, etc. without
removing the wing.
• Two-piece, plug-in wings make
transporting simple.
• Great flying characteristics.
Cons:
• The instruction manual has a couple
of typos.
• The window does not lock in place
with the door-latch mechanism. (See
text.)
The author chose a Swiss Cub’s color scheme. From this angle you could almost mistake it for full scale.
When you couple the Cub’s flying characteristics with the realistic sound of a fourstroke
engine, you end up with a great Scale model.
EVERYBODY LOVES a Cub—or is that a
clown? I guess it depends on whom you ask;
they’re probably interchangeable. One thing
is for sure, though: Mr. Piper’s J-3 Cub is
one of the most-modeled, -flown, and -loved
designs in Radio Control. It is one of the few
designs that flies as well in model form as it
does in full-scale form.
Being the advertising representative for
Model Aviation, normally my only
involvement in product reviews is to help set
them up and lend a hand with the
photography. But when Sig’s 1⁄5-scale kit
arrived for initial photography, I talked
Aeromodeling Editor Bob Hunt into letting
me take a stab at reviewing it.
First Impressions: The first thing I noticed
when I opened the box was that this was a
ready-to-assemble kit. There was a fair
amount of wood, three rolled sheets of fullsize
plans, several bags of hardware, some
vacuum-formed white ABS parts, clear
vacuum-formed windows, and a fiberglass
cowl.
Luckily, a nicely illustrated instruction
manual was included to tell me how to put
all those pieces together. The front of the
manual had diagrams showing all the lasercut
pieces’ names. Before getting too far into
things, be sure to label each of these parts
before they fall out. Doing so now can save a
great deal of time later!
Construction: A kit usually starts with
building the fuselage or the wings. Not so
with the Cub. In this case you start with a
few subassemblies, one of which is
mounting the engine on the firewall. I was a
bit skeptical about doing this step so early in
construction, but as you’ll see later, the
people at Sig know what they’re doing.
84 MODEL AVIATION
April 2004 85
Sig’s 1⁄5-scale Cub comes as a ready-to-assemble kit. There is a fair amount of parts, but
all pieces are high quality and everything goes together quickly.
The airframe is complete, sanded, and ready for covering. Spending a couple hours a
night, it took approximately a week to get to this point.
Flying almost any Cub is relaxing. With the recommended
throws, this model is a smooth flier and a gentle barnstormer.
Caught right after takeoff on maiden flight, the Cub flew great,
needing slight right rudder trim for hands-off flight.
I chose one of the RCV .56 engines to
power my Cub. This engine proved to be a
nice, compact size that fit into the cowl
without additional cutouts. I mated the
engine with a Performance Specialties fourstroke
muffler and a 90° adapter, which put
the exhaust out the bottom of the cowl.
Another step that seemed premature was
building the fuselage’s servo tray and
mounting the throttle, rudder, and elevator
servos. Those things are not normally done
until much later, but Sig says to do it so I
did.
Other subassemblies included
premounting blind nuts for the tail wheel and
wing struts and gluing in plywood pieces to
strengthen the fuselage sides.
Wing: After the subassemblies, you start on
the wings. This Cub’s design features a twopiece,
plug-in wing system, so each half is
built separately. There’s nothing tricky
here—average rib and spar construction.
Because of the accurate laser-cutting,
everything locks into place nicely and
there’s no need for sanding. In just a few
minutes an entire wing panel can be laid out
and ready for gluing.
Once everything has been trued up and
glued into position, you apply sheeting to the
leading edge and the inboard section.
Capstrips and sheeting around the aileron
area are also applied at this time.
Flipping the wing over, you apply
additional sheeting to the leading edge and
inboard section. You glue in four of the
preassemblies making up the strut mounts,
and then capstrips finish off the bottom.
After you have glued in the tip pieces, the
wing half is finished and ready for sanding.
The interlocking construction makes a wing
that is strong and quite resistant to flexing.
After repeating the steps for the other wing,
build the ailerons. Using a number of
formers, which fit into precut top and bottom
sheeting, the ailerons come out much lighter
than solid balsa would.
Tail Surfaces: The fin, stabilizer, rudder,
and elevator halves are of simple,
straightforward construction. As you’ll see
later, the tail surfaces are all braced. Where
Photos by the author
the attachment points are, you cut dowels to
length and insert them into precut holes. This
makes for a much stronger attachment point
than balsa would.
Fuselage: Putting the fuselage together is
similar to the wing, in that all parts are dryassembled
and then glued into a single piece.
The design is somewhat typical because there
are slab sides with formers in between.
However, Sig put in a few neat things.
Many kits that utilize slab sides for the
fuselage simply use two pieces of plywood for
the sides. Although it’s strong, the plywood
makes for extra sanding, and covering
plywood with iron-on film can be difficult.
This Cub goes a step beyond; the plywood’s
outer surfaces are covered with thin balsa
sheeting, which is laser-cut to match the
plywood exactly. It’s easy to sand and a breeze
to cover.
The formers’ interlocking design, along
with the laser-cutting, makes everything fit
well. You literally build the fuselage in your
hands—no pinning it to a board. Even so, after
everything is clamped or taped together, the
alignment is straight and true. Well done, Sig!
Adding to the Cub’s scale look is a series
of stringers that are glued over the slab sides.
You’ll need to do a bit of trimming and
sanding to get the stringers to the right size and
shape, but the effort is well worth it when the
model is covered.
The other features that set this Cub apart
from the previous Sig kits are the functional
door and window on the starboard side.
Although some time is needed to ensure that
everything is properly aligned, it works well.
However, I still don’t understand why only
the bottom portion of the door is held in with
the latch mechanism. It’s true that the airflow
will keep the window portion of the door
closed, but having the door’s upper edge
overlap the window (instead of the other way
around) would lock everything in place. Oh
well. I guess Sig has its reasons.
Landing Gear: The stock landing gear
included with the kit will work fine. It is rigid
but requires soldering and a bit of work. I
decided to use the Robart Cub gear. The
Robart design incorporates a functional shockabsorbing
system similar to that of the fullscale
Cub. It comes ready to assemble and
takes approximately five minutes to put
together.
If you use the Robart gear, mounting is
different. Sig’s gear is pressed into grooved
hardwood blocks and held in place with gear
straps. Robart’s system requires you to drill
holes to bolt the gear directly to the fuselage
belly. A drilling template is provided, which
makes this easy. If you line it up correctly, you
can drill into the hardwood blocks and still use
them by using blind nuts from the inside.
Oh, and if you decide to use the Robart
gear, flip the hardwood landing-gear blocks
over before gluing in place. This puts the
smooth surface on the outside.
The gear itself is manufactured from 4130
tubular steel frames that are welded together.
The pivot pins and mounting screws are
hardened and plated. All pieces are held
together with c-clips and hex bolts with lock
nuts.
After everything was mounted and working
properly, I removed the pieces. I had to come
up with a “filler” to cover the port and
starboard frames. For this I epoxied thin
styrene sheeting to the frames, and then I
painted all the pieces to match the airplane’s
color scheme.
Once assembled, the rubber bungees give a
nice amount of flex. The gear is firm enough
not to give while taxiing, but it provides just
the right amount of flex to take the bounce out
of harder landings.
Final Assembly: After all the major pieces
were finished, I made the port and starboard
struts to support the wings. I constructed those
struts from hardwood pieces which were
trimmed and glued into a “V” shape, and then
I slotted the ends to accept aluminum
mounting brackets.
The midpoint of the struts require you to
cut and form smaller “jury” support struts from
the supplied brass tubing. This is probably one
of the longer steps because once all the precise
fitting is finished, you should sand the
hardwood to a more aerodynamic shape. The
plans include full-size drawings of all the
struts, including bending angles and drilling
guides, making all this much easier.
After thoroughly sanding the entire
airframe, I covered the Cub with Coverite’s
21st Century fabric covering. Since I also had
plans to try my hand at Scale competition, I
copied the color scheme of a full-scale Cub. I
chose it because the white and blue with red
trim stands out compared to the more typical
Cub schemes.
With covering completed, the tail struts are
next. You make them by cutting the supplied,
threaded rod to length and soldering a
modified clevis to one end while threading
another modified clevis to the other end. After
all four struts are made and adjusted to the
proper length, attach them.
Trim the windows and glue them into
position. There’s nothing tricky here, but the
front windshield will require a bit of trial-anderror
trimming so it will clear the leading edge
of the wings.
The cowl is one piece and made from
fiberglass. It has no holes at all, so you have to
do all the work yourself. Take your time when
doing this; you don’t want holes to be larger
than needed—or worse, in the wrong place.
The manual shows where the holes should be,
but you’ll have to do the measuring.
To finish the cowl’s scale look there are
vacuum-formed ABS dummy engine halves.
These need to be trimmed to fit. Although
they’re not extremely detailed, once attached
and painted they add a bit of realism when
viewed from a few feet away.
All the control hookups are
straightforward, consisting of flexible
pushrods for the elevator and throttle. I found
the need to add a few small, plywood brackets
made from scrap along the length of the
throttle pushrod to keep it from flexing.
A pull-pull system is used on the rudder
and can take some time to install. The system
itself works fine, but it is difficult to thread the
thin wire through the covered fuselage and not
have it get caught on formers or find its way
between the fuselage sides and the covering.
While I was finishing up these details, I
realized why Sig instructs builders to mount
the engine and the servos right away. It would
be almost impossible to get to the back of the
firewall and tough to mount the servos once
the fuselage was assembled. As always, it’s
good to follow the instructions—even if things
look out of order.
With everything completed, the Cub
balanced as it should have. Not bad
considering the extra weight of the fabric
covering, a larger 1100 mAh battery (for long
flying days), the Robart gear, and the Du-Bro
wheels. The final weight—ready to fly in scale
trim—was 8 pounds.
Flying: No matter how many kits I build, I
still get “butterflies” on every maiden flight.
This time was even more so since I’d put more
than the usual time in this Cub.
Assembling the Cub at the field takes
roughly five minutes. You slide each wing half
into position with an aluminum tube riding
snugly in the installed phenolic tube. A 10-32
bolt holds the wing in place while the strut is
attached. Each wing strut requires five 4-40
screws to hold it in position.
Once the wings are on, you install the top
hatch with two more 4-40 screws. This hatch
doubles as a limiter for the aluminum wing
tubes. (Be sure to pack a few extra screws,
washers, and lock nuts; you never know when
you’ll drop one!)
The functional door is a great idea; it gives
you good access to plug in the aileron servos
with the wing and struts attached. I also took
advantage of this to hide the radio’s switch and
a remote glow plug in the cockpit area.
After assembly and a quick preflight check,
I was ready to go. I started the engine and let it
warm up, and then I started to taxi the Cub.
After approximately 30 seconds of running
time, the engine quit. When I went back to the
pits to restart the engine, it wouldn’t fire no
matter what I did. Grumble, grumble, and back
home for the day.
At home I removed the engine and tried
restarting it on my test bench. It wouldn’t fire.
I threw everything at it: new plugs, different
fuel tanks, the works. Frustrated, I decided to
solve the problem with a radical solution: I
switched to a different engine. I had a Saito 56,
and it fit with a few changes and several more
cutouts in the cowl.
With the engine problem resolved, I was
off for the first flight. The Cub lifted off as it
should and required just a bit of right rudder
trim. Using the suggested throws, it flew
nicely and did everything I asked it to do. Mild
aerobatics—loops, barrel rolls, stall turns, and
the like—-were scalelike. This model doesn’t
do much more than that, but the full-scale Cub
doesn’t do much more either.
Under low power settings the model
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slowed nicely and remained responsive, even
when close to stall speed. Good, bounce-free
landings can be performed routinely—
probably because of the Robart bungee
system.
As you can probably tell, I am having a
blast flying the Cub. It has a great scale
presence in the air and makes for a nice
barnstormer. Since the maiden flight I have
logged a ton of time with the Cub, practicing
Scale maneuvers for competition. I entered it
in Fun Scale at last year’s Nationals.
Sig has a winner on its hands with this Cub.
It’s quick and fun to build and flies just like
you would expect a Cub to fly. Paired with a
four-stroke engine in the 56-61 range, it will
have all the power it needs with a fantastic
scale sound. If you’re a Radio Control pilot
but have never tried your hand at building a
kit, this is a great choice. MA
(Editor’s note: It is our policy to send a
copy of each review to the manufacturer
whose product is being evaluated. Sig
Manufacturing responded to a couple
comments the author made in the “Cons”
section of this review.
First, Sig wanted readers to know that the
typos in the instruction booklet have been
corrected.
Second, the company pointed out that
the upper side door does not have a
retainer because in actual practice it does
not need retention; it is held firmly in
place under compression with the top side
of the lower hinged door.
Sig informed us that after flying several of
these models in the past two years, both
hinged doors stayed firmly closed unless the
modeler purposely opened them for radio
access. In short, they were designed that
way.)
Specifications:
Wingspan: 84.5 inches
Wing area: 947 square inches
Length: 55.25 inches
Model weight recommended: 7-7.5 pounds
Review model’s weight (ready to fly): 8
pounds (with items added for Scale
competition)
Engine recommended: .40-.46 two-stroke or
45-65 four-stroke
Engine used: Saito 56 four-stroke
Radio recommended: four-channel with five
servos
Radio used: JR 8103 transmitter, JR R700
receiver, five Expert SL571 servos, JR Extra
1100 mAh battery
Materials used in construction: balsa,
plywood, fiberglass (cowl)
Street Price: $129
Manufacturer/distributor:
Sig Manufacturing
Box 520
Montezuma IA 50171
(641) 623-5154
www.sigmfg.com
Products used:
JR 8103 radio system, Saito 56 engine, 1⁄5-
scale civilian pilot:
Horizon Hobby Distributors
4105 Fieldstone Rd.
Champaign IL 61822
(217) 352-1913
www.horizonhobby.com
1⁄5th-scale Cub gear:
Robart Manufacturing, Inc.
625 N. 12th St.
Saint Charles IL 60174
(630) 584-7616
www.robart.com
Fill-It Fueling System, 1⁄5-scale Cub wheels:
Du-Bro Products
Box 815
Wauconda IL 60084
(847) 526-2136
www.dubro.com
Master Airscrew 12 x 6 two-blade propeller:
Windsor Propeller Co., Inc.
Box 250
Rancho Cordova CA 95741
www.masterairscrew.com
10-ounce fuel tank:
Sullivan Products
1 North Haven St.
Baltimore MD 21224
(410) 732-3500
www.sullivanproducts.com
90 MODEL AVIATION