58 MODEL AVIATION
Park View: Model Airplane Engineering Jinx
MICHAEL RAMSEY
An RC electric
park flyer with
twin motors and
a twist or two
This is a twin-motor model that excels in
3-D performance. It’s extremely agile but
also predictable.
The Jinx is easy to assemble since the parts are interlocking with alignment tabs built in.
The greatest elevator area is located directly behind the motors.
Hidden on the underside is the Castle
Creations Thunderbird-9 brushless ESC
that perfectly operates two Westport CDROM
motors.
The MAE Jinx is made from CNC-cut 6mm black Depron-foam parts. The vibrant blackand-
yellow graphics are screen-printed onto the components.
IF YOU’RE IN the mood for something
different, the Jinx from Model Airplane
Engineering (MAE) is definitely worth
trying. Its aquatic outline has the presence of
a shark/manta ray hybrid.
Come to think of it, swimming through
water is a lot like flying through air, less the
attributes of buoyancy. Given that this model
is made with the qualities acquainted with a
foamie (light enough to be nearly buoyant),
perhaps this arrangement of airplane and fish
has its positive points.
As of late, given the benefits of foam
construction techniques and lightweight
electric-power systems, kit designers have
been able to explore wilder aircraft concepts.
The Jinx employs many rare features that are
combined to create a model that a pilot can
appreciate from a number of perspectives.
To begin with, it is a twin-power-plant
design—a feature for which electric power is
well suited because the prospect of an
engine-out situation is virtually gone. The
motors are placed fairly close to the fuselage
centerline, which removes any chance of an
isometric thrust problem. The engine
nacelles’ vertical profile stabilizes engine
thrust and offers the benefit of lateral (sideforce)
stability.
The curved outlines make the Jinx stand
out next to any other model that may be at
the flightline. However, designer Jeff Krebs
purposely applied the design elements to
achieve handling qualities the novice to
expert pilot could appreciate.
For instance, the airplane’s tail surfaces
dominate the profile with an evil “shark”
attitude, but the displacement of area on the
elevators is located as close to in-line with
the motors as possible. The advantage is
better elevator-input authority during slow-
10sig2.QXD 8/24/06 9:26 AM Page 58October 2006 59
The Bluebird 306 servos are light and
strong. Most popular submicroservos will
fit into the precut servo openings. The Jinx is available as a stand-alone kit or as a complete package from MAE.
The Hitec 05 receiver reserves the fifth
channel for flap control. This way the
tiperons can also be programmed for flap
and air-brake controls.
The tiperons rotate around the 4mm
carbon-fiber-tube spar. The accurately
shaped hardware and linkage is provided
on a laser-cut 1/32 sheet.
speed (high-alpha) maneuvers. The
vertical fin’s dorsal design keeps the
rudder powerfully effective even though it
isn’t directly in line with the propeller
blast.
Observing the fuselage profile we can
see a cockpit canopy outline; lo and
behold, it’s not a fish after all. The
enormous canopy’s forward position
promotes lateral stability, not only at high
speed but also in knife-edge flight. In
addition, the long nose offers a place in
which to put the battery on this puffed-up
(that’s fish talk)-empennage design.
Looking at the airplane from the top, you
can see the manta ray outline in the shape of
the wings. The wide root area promotes lift
for 3-D maneuvers while the narrower wings
are left to employ this sport model design’s
“secret weapon.” The wing sections outboard
of the engine nacelles are designed as
tiperons; for roll control the entire
wingtips rotate around a carbon-fiber spar,
offering outrageous roll input authority.
Below: The Jinx requires only a light underhand toss to launch. With the motors at full
power, a learned pilot may just need to let go for the Jinx to climb out vertically.
Photos by Mark Lanterman and the author
10sig2.QXD 8/24/06 9:29 AM Page 5960 MODEL AVIATION
Test-Model Details
Motor (two): Westport Design 20T
CD-ROMs
Battery (one): 7.4-volt, 1250 mAh
or 11.1-volt, 700 mAh Li-Poly
Propeller (two): GWS 8 x 4 direct
drive or GWS 7 x 3.5 direct drive
Static draw: 7.1 amps
Motor output: 72 watts at 10.2 volts
Radio system: Hitec Optic 6
transmitter, Hitec Micro 05S receiver,
four Bluebird 306 microservos, two 6-
inch servo extensions, single Castle
Creations Thunderbird-9 ESC
Ready-to-fly weight: 9.2 ounces
Flight duration: Eight to 14 minutes
• Fast and easy to build with vibrant
screen-printed graphics
• Economical, efficient, powerful power
system
• Fun to fly with an impressive
performance envelope
Pluses and Minuses
+
- • None. (Honest!) Wait! Does fishy
count?
Type: RC sport flat-foam kit
Pilot skill level: Intermediate
Wingspan: 39 inches
Wing area: 275 square inches
Length: 31.5 inches
Weight: 8.5-9.5 ounces
Wing loading: 4.71 ounces per
square foot (average)
Power (recommended): Dual
brushless CD-ROM motor
Radio: Four channels minimum, four
submicroservos
Construction: Black Depron sheet
foam with carbon-fiber-tubing
reinforcement
Covering/finish: Preapplied,
screened two-color graphics
Price: $59.95
Specifications
leaves fuzzy edges on the foam, so I dressed
the outer edges of the parts using 180-grit
sandpaper and left the tab-and-notch gluejoint
areas as provided.
As instructed, I used UHU Creative
cement (also available from MAE) to
assemble the foam parts. This adhesive
works like rubber cement, where adhesive is
evenly applied to the contact areas and then
allowed a few minutes to tack-dry before
permanently joining them.
The process takes a bit longer than
assembly methods using foam-safe
cyanoacrylate. The benefit of the UHU is
that it’s as flexible as the Depron foam
when cured, whereas cyanoacrylate joints
are brittle.
Along with the four-page illustrated
instruction manual provided, the MAE Web
page has full-color photos of key areas to
complement the building process. I was
grateful to find those photos because the
directions regarding the tiperons were a bit
gray (pun intended; the illustrations in the
manual are in grayscale) to me.
The detailed photos cleared up all my
concerns, and the build sped along. I had the
Jinx ready to fly after roughly three relaxing
evenings of work.
I deviated from the instructions only
during the horizontal fuselage and wing
construction. While this assembly was flat I
advanced to the elevator installation and
hinged it to the stabilizer. I predicted that if
I installed the elevator after the vertical
portions of the fuselage were attached,
hinging would be awkward to complete
neatly.
The Jinx was a snap to build straight.
Because I ordered the recommended radio
accessories with the kit, everything was a
drop fit into the precut locations. I decorated
the laser-cut 1/32 plywood control horns with
black marker so they matched the black color
scheme; in addition, it gives them the hightech
look of carbon fiber.
Low-temperature hot glue holds the
servos in place. Velcro (included) is used to
mount the receiver in the tail, and the battery
Jinx on the Bench: This model is available
direct from MAE as a stand-alone kit,
packaged with “plug-and-fly” motors, or
bundled with everything but the receiver.
The company’s Web site is a one-stop
shopping experience.
I used all the accessories and equipment
recommended by the manufacturer, and
overall I’m extremely pleased with the
outcome. Unless you have an overflowing
parts drawer, you won’t go wrong with a
package purchase.
The Jinx has been engineered to a
practical size; a one-piece model with a
wingspan exceeding 40 inches is a pain to
transport. With that in mind, the Jinx
worked out to where it could use an
economical set of brushless motors.
The Westport Design power plants are
essentially CD-ROM motors built to suit
electric-powered aircraft. The motors that
are recommended for the Jinx have been
wound with 20 turns of 25-gauge wire in
the WYE parallel termination.
The motors don’t need a gearbox since
they’re outrunners, and the way my set was
packaged, with the lead wiring in place, all
that was left for me to do was connect the
speed control. That’s right; a single
Thunderbird-9 ESC is effectively
controlling both motors on my Jinx.
The builder has the option of employing
a two- or three-cell Li-Poly battery setup.
To keep the Westport motors within their
12-amp output range, GWS direct-drive
propellers are 8 and 7 inches respectively.
I fly many two-cell systems in this
foamie class. I test-flew this model with
that setup and experienced satisfying
performance. I tried the three-cell system
too because it was reported to give
“zippier” performance (which it did). It’s
nice to have options.
The kit is neatly packed by hand. The
CNC router-cut parts are taped to a rigid
cardboard sheet so the screen-printed parts
are less likely to be damaged. The router
as far forward as possible. Just enough music
wire is provided to make straight pushrods.
My pushrods were assembled as two pieces
joined with heat-shrink tubing and
cyanoacrylate.
With the servos so close to the control
surfaces, there’s almost no flex in the control
linkage. To get the 45°-70° of control throw
permitted in the ailerons, it might be
necessary to use the extra-long servo arms
made by Du-Bro (items 930 through 933). I
used the longest arm included with the
Bluebird 306 servos.
Low rate control was programmed with
half the maximum available throw. On high
rates the elevator and rudder deflect
approximately 50° each. The tiperons rotate
roughly 35° (which is plenty for a blinding
roll rate).
Exponential was programmed into the
high rates to soften the control-stick feel
around neutral. The recommended 70%
setting seemed appropriate and proved to
work well.
Jinx in the Air: The model’s lack of
undercarriage requires a hand launch and a
soft place to land. I first flew it with the twocell
Li-Poly battery and 8 x 4 propellers. An
underhand toss was all it needed for a safe
launch.
More than enough power was available to
accelerate straight up from a hovering
standstill. The Jinx’s WOT (wide-openthrottle)
speed was comfortable with half
throttle used for cruising and full throttle for
up-lines and emergency rescue (read obstacle
avoidance).
I have to admit that the Jinx is sensitive to
control-surface inputs. Some might call it
“twitchy”; I prefer to use the word “capable”
when describing its flying qualities.
This is a capable 3-D flier—probably the
most capable twin-motor aircraft I’ve ever
flown. Its agility quickly builds pilot
confidence, encouraging you to fly the
aircraft into tumbling maneuvers that seem
to defy gravity and imagination.
Almost the only handicap the Jinx has is
its rudder effectiveness while in a hover.
The propeller blast just can’t touch the
10sig2.QXD 8/24/06 9:29 AM Page 60rudder, so yaw control isn’t as responsive as
with a foamie with a single motor mounted in
the nose.
I could hover the Jinx after some practice,
but it reminded me of what a fish looks like
when it’s pulled from the water, with its tail
(or rudder in this case) flapping wildly
behind.
If rolling fast is your thing, the Jinx will
never fail to please. I thought my Ultra Stick
with its quadruple-aileron feature had a fast
roll rate; the Jinx is blinding. Of course, the
aileron response and roll rate are a product of
whatever the model’s airspeed is at the time.
The most crowd-pleasing maneuver I’ve
done so far is a stunt called the Blender
Bender (which I first saw on the MAE Web
site video page). After climbing to altitude,
point the Jinx straight down and pull the
throttle back to idle. With full aileron input,
the Jinx appears to drill itself down through
the air.
As the ground closes in and the roll rate
seems to be the most intense, quickly apply
full down-elevator and rudder. The Jinx stops
so fast, it’s almost as if it hits an invisible
floor. Finally, with the controls held at the
limits, smoothly add throttle back in so the
Jinx can perform rolling tumbles in a circle
with no further loss of altitude.
Of the two- and three-cell power
configurations, I’m happier flying the Jinxwith the faster 11.1-volt battery. The extra
zip the motors give turning at higher speeds
picks up the pace for air-show antics. The
Jinx will hover better using larger 8 x 4
propellers; the larger thrust area improves
control effectiveness. So for slow-speed
maneuvers (Harriers and the like), the twocell
power configuration is the better choice.
One other optional setup to play with is
flaperon control. With each aileron
connected on separate channels, they can be
mixed to function as flaps.
Not that the Jinx needs this input to slow
down or land, but the fun part is mixing the
flap control in with the elevator. When you
slave the flaps to the elevator, often regarded
as the air-brake function, whenever elevator
is used, an allotted amount of flap moves
with them.
The tiperons rotate back when upelevator
is applied and forward with downelevator.
I can turn the mix on and off, only
using the function to perform tight loops,
tumbles, and 50°-85° high-alpha passes.
The Jinx is a blast! It’s easy to gather a large
collection of foamies quickly. As much fun
as they can be to play with, many of them fly
alike.
An active RC pilot looks for something
different. The Jinx is distinctive in looks and
performance, including a bag of tricks that
won’t fail to surprise. MA
Michael Ramsey
Edition: Model Aviation - 2006/10
Page Numbers: 58,59,60,62
Edition: Model Aviation - 2006/10
Page Numbers: 58,59,60,62
58 MODEL AVIATION
Park View: Model Airplane Engineering Jinx
MICHAEL RAMSEY
An RC electric
park flyer with
twin motors and
a twist or two
This is a twin-motor model that excels in
3-D performance. It’s extremely agile but
also predictable.
The Jinx is easy to assemble since the parts are interlocking with alignment tabs built in.
The greatest elevator area is located directly behind the motors.
Hidden on the underside is the Castle
Creations Thunderbird-9 brushless ESC
that perfectly operates two Westport CDROM
motors.
The MAE Jinx is made from CNC-cut 6mm black Depron-foam parts. The vibrant blackand-
yellow graphics are screen-printed onto the components.
IF YOU’RE IN the mood for something
different, the Jinx from Model Airplane
Engineering (MAE) is definitely worth
trying. Its aquatic outline has the presence of
a shark/manta ray hybrid.
Come to think of it, swimming through
water is a lot like flying through air, less the
attributes of buoyancy. Given that this model
is made with the qualities acquainted with a
foamie (light enough to be nearly buoyant),
perhaps this arrangement of airplane and fish
has its positive points.
As of late, given the benefits of foam
construction techniques and lightweight
electric-power systems, kit designers have
been able to explore wilder aircraft concepts.
The Jinx employs many rare features that are
combined to create a model that a pilot can
appreciate from a number of perspectives.
To begin with, it is a twin-power-plant
design—a feature for which electric power is
well suited because the prospect of an
engine-out situation is virtually gone. The
motors are placed fairly close to the fuselage
centerline, which removes any chance of an
isometric thrust problem. The engine
nacelles’ vertical profile stabilizes engine
thrust and offers the benefit of lateral (sideforce)
stability.
The curved outlines make the Jinx stand
out next to any other model that may be at
the flightline. However, designer Jeff Krebs
purposely applied the design elements to
achieve handling qualities the novice to
expert pilot could appreciate.
For instance, the airplane’s tail surfaces
dominate the profile with an evil “shark”
attitude, but the displacement of area on the
elevators is located as close to in-line with
the motors as possible. The advantage is
better elevator-input authority during slow-
10sig2.QXD 8/24/06 9:26 AM Page 58October 2006 59
The Bluebird 306 servos are light and
strong. Most popular submicroservos will
fit into the precut servo openings. The Jinx is available as a stand-alone kit or as a complete package from MAE.
The Hitec 05 receiver reserves the fifth
channel for flap control. This way the
tiperons can also be programmed for flap
and air-brake controls.
The tiperons rotate around the 4mm
carbon-fiber-tube spar. The accurately
shaped hardware and linkage is provided
on a laser-cut 1/32 sheet.
speed (high-alpha) maneuvers. The
vertical fin’s dorsal design keeps the
rudder powerfully effective even though it
isn’t directly in line with the propeller
blast.
Observing the fuselage profile we can
see a cockpit canopy outline; lo and
behold, it’s not a fish after all. The
enormous canopy’s forward position
promotes lateral stability, not only at high
speed but also in knife-edge flight. In
addition, the long nose offers a place in
which to put the battery on this puffed-up
(that’s fish talk)-empennage design.
Looking at the airplane from the top, you
can see the manta ray outline in the shape of
the wings. The wide root area promotes lift
for 3-D maneuvers while the narrower wings
are left to employ this sport model design’s
“secret weapon.” The wing sections outboard
of the engine nacelles are designed as
tiperons; for roll control the entire
wingtips rotate around a carbon-fiber spar,
offering outrageous roll input authority.
Below: The Jinx requires only a light underhand toss to launch. With the motors at full
power, a learned pilot may just need to let go for the Jinx to climb out vertically.
Photos by Mark Lanterman and the author
10sig2.QXD 8/24/06 9:29 AM Page 5960 MODEL AVIATION
Test-Model Details
Motor (two): Westport Design 20T
CD-ROMs
Battery (one): 7.4-volt, 1250 mAh
or 11.1-volt, 700 mAh Li-Poly
Propeller (two): GWS 8 x 4 direct
drive or GWS 7 x 3.5 direct drive
Static draw: 7.1 amps
Motor output: 72 watts at 10.2 volts
Radio system: Hitec Optic 6
transmitter, Hitec Micro 05S receiver,
four Bluebird 306 microservos, two 6-
inch servo extensions, single Castle
Creations Thunderbird-9 ESC
Ready-to-fly weight: 9.2 ounces
Flight duration: Eight to 14 minutes
• Fast and easy to build with vibrant
screen-printed graphics
• Economical, efficient, powerful power
system
• Fun to fly with an impressive
performance envelope
Pluses and Minuses
+
- • None. (Honest!) Wait! Does fishy
count?
Type: RC sport flat-foam kit
Pilot skill level: Intermediate
Wingspan: 39 inches
Wing area: 275 square inches
Length: 31.5 inches
Weight: 8.5-9.5 ounces
Wing loading: 4.71 ounces per
square foot (average)
Power (recommended): Dual
brushless CD-ROM motor
Radio: Four channels minimum, four
submicroservos
Construction: Black Depron sheet
foam with carbon-fiber-tubing
reinforcement
Covering/finish: Preapplied,
screened two-color graphics
Price: $59.95
Specifications
leaves fuzzy edges on the foam, so I dressed
the outer edges of the parts using 180-grit
sandpaper and left the tab-and-notch gluejoint
areas as provided.
As instructed, I used UHU Creative
cement (also available from MAE) to
assemble the foam parts. This adhesive
works like rubber cement, where adhesive is
evenly applied to the contact areas and then
allowed a few minutes to tack-dry before
permanently joining them.
The process takes a bit longer than
assembly methods using foam-safe
cyanoacrylate. The benefit of the UHU is
that it’s as flexible as the Depron foam
when cured, whereas cyanoacrylate joints
are brittle.
Along with the four-page illustrated
instruction manual provided, the MAE Web
page has full-color photos of key areas to
complement the building process. I was
grateful to find those photos because the
directions regarding the tiperons were a bit
gray (pun intended; the illustrations in the
manual are in grayscale) to me.
The detailed photos cleared up all my
concerns, and the build sped along. I had the
Jinx ready to fly after roughly three relaxing
evenings of work.
I deviated from the instructions only
during the horizontal fuselage and wing
construction. While this assembly was flat I
advanced to the elevator installation and
hinged it to the stabilizer. I predicted that if
I installed the elevator after the vertical
portions of the fuselage were attached,
hinging would be awkward to complete
neatly.
The Jinx was a snap to build straight.
Because I ordered the recommended radio
accessories with the kit, everything was a
drop fit into the precut locations. I decorated
the laser-cut 1/32 plywood control horns with
black marker so they matched the black color
scheme; in addition, it gives them the hightech
look of carbon fiber.
Low-temperature hot glue holds the
servos in place. Velcro (included) is used to
mount the receiver in the tail, and the battery
Jinx on the Bench: This model is available
direct from MAE as a stand-alone kit,
packaged with “plug-and-fly” motors, or
bundled with everything but the receiver.
The company’s Web site is a one-stop
shopping experience.
I used all the accessories and equipment
recommended by the manufacturer, and
overall I’m extremely pleased with the
outcome. Unless you have an overflowing
parts drawer, you won’t go wrong with a
package purchase.
The Jinx has been engineered to a
practical size; a one-piece model with a
wingspan exceeding 40 inches is a pain to
transport. With that in mind, the Jinx
worked out to where it could use an
economical set of brushless motors.
The Westport Design power plants are
essentially CD-ROM motors built to suit
electric-powered aircraft. The motors that
are recommended for the Jinx have been
wound with 20 turns of 25-gauge wire in
the WYE parallel termination.
The motors don’t need a gearbox since
they’re outrunners, and the way my set was
packaged, with the lead wiring in place, all
that was left for me to do was connect the
speed control. That’s right; a single
Thunderbird-9 ESC is effectively
controlling both motors on my Jinx.
The builder has the option of employing
a two- or three-cell Li-Poly battery setup.
To keep the Westport motors within their
12-amp output range, GWS direct-drive
propellers are 8 and 7 inches respectively.
I fly many two-cell systems in this
foamie class. I test-flew this model with
that setup and experienced satisfying
performance. I tried the three-cell system
too because it was reported to give
“zippier” performance (which it did). It’s
nice to have options.
The kit is neatly packed by hand. The
CNC router-cut parts are taped to a rigid
cardboard sheet so the screen-printed parts
are less likely to be damaged. The router
as far forward as possible. Just enough music
wire is provided to make straight pushrods.
My pushrods were assembled as two pieces
joined with heat-shrink tubing and
cyanoacrylate.
With the servos so close to the control
surfaces, there’s almost no flex in the control
linkage. To get the 45°-70° of control throw
permitted in the ailerons, it might be
necessary to use the extra-long servo arms
made by Du-Bro (items 930 through 933). I
used the longest arm included with the
Bluebird 306 servos.
Low rate control was programmed with
half the maximum available throw. On high
rates the elevator and rudder deflect
approximately 50° each. The tiperons rotate
roughly 35° (which is plenty for a blinding
roll rate).
Exponential was programmed into the
high rates to soften the control-stick feel
around neutral. The recommended 70%
setting seemed appropriate and proved to
work well.
Jinx in the Air: The model’s lack of
undercarriage requires a hand launch and a
soft place to land. I first flew it with the twocell
Li-Poly battery and 8 x 4 propellers. An
underhand toss was all it needed for a safe
launch.
More than enough power was available to
accelerate straight up from a hovering
standstill. The Jinx’s WOT (wide-openthrottle)
speed was comfortable with half
throttle used for cruising and full throttle for
up-lines and emergency rescue (read obstacle
avoidance).
I have to admit that the Jinx is sensitive to
control-surface inputs. Some might call it
“twitchy”; I prefer to use the word “capable”
when describing its flying qualities.
This is a capable 3-D flier—probably the
most capable twin-motor aircraft I’ve ever
flown. Its agility quickly builds pilot
confidence, encouraging you to fly the
aircraft into tumbling maneuvers that seem
to defy gravity and imagination.
Almost the only handicap the Jinx has is
its rudder effectiveness while in a hover.
The propeller blast just can’t touch the
10sig2.QXD 8/24/06 9:29 AM Page 60rudder, so yaw control isn’t as responsive as
with a foamie with a single motor mounted in
the nose.
I could hover the Jinx after some practice,
but it reminded me of what a fish looks like
when it’s pulled from the water, with its tail
(or rudder in this case) flapping wildly
behind.
If rolling fast is your thing, the Jinx will
never fail to please. I thought my Ultra Stick
with its quadruple-aileron feature had a fast
roll rate; the Jinx is blinding. Of course, the
aileron response and roll rate are a product of
whatever the model’s airspeed is at the time.
The most crowd-pleasing maneuver I’ve
done so far is a stunt called the Blender
Bender (which I first saw on the MAE Web
site video page). After climbing to altitude,
point the Jinx straight down and pull the
throttle back to idle. With full aileron input,
the Jinx appears to drill itself down through
the air.
As the ground closes in and the roll rate
seems to be the most intense, quickly apply
full down-elevator and rudder. The Jinx stops
so fast, it’s almost as if it hits an invisible
floor. Finally, with the controls held at the
limits, smoothly add throttle back in so the
Jinx can perform rolling tumbles in a circle
with no further loss of altitude.
Of the two- and three-cell power
configurations, I’m happier flying the Jinxwith the faster 11.1-volt battery. The extra
zip the motors give turning at higher speeds
picks up the pace for air-show antics. The
Jinx will hover better using larger 8 x 4
propellers; the larger thrust area improves
control effectiveness. So for slow-speed
maneuvers (Harriers and the like), the twocell
power configuration is the better choice.
One other optional setup to play with is
flaperon control. With each aileron
connected on separate channels, they can be
mixed to function as flaps.
Not that the Jinx needs this input to slow
down or land, but the fun part is mixing the
flap control in with the elevator. When you
slave the flaps to the elevator, often regarded
as the air-brake function, whenever elevator
is used, an allotted amount of flap moves
with them.
The tiperons rotate back when upelevator
is applied and forward with downelevator.
I can turn the mix on and off, only
using the function to perform tight loops,
tumbles, and 50°-85° high-alpha passes.
The Jinx is a blast! It’s easy to gather a large
collection of foamies quickly. As much fun
as they can be to play with, many of them fly
alike.
An active RC pilot looks for something
different. The Jinx is distinctive in looks and
performance, including a bag of tricks that
won’t fail to surprise. MA
Michael Ramsey
Edition: Model Aviation - 2006/10
Page Numbers: 58,59,60,62
58 MODEL AVIATION
Park View: Model Airplane Engineering Jinx
MICHAEL RAMSEY
An RC electric
park flyer with
twin motors and
a twist or two
This is a twin-motor model that excels in
3-D performance. It’s extremely agile but
also predictable.
The Jinx is easy to assemble since the parts are interlocking with alignment tabs built in.
The greatest elevator area is located directly behind the motors.
Hidden on the underside is the Castle
Creations Thunderbird-9 brushless ESC
that perfectly operates two Westport CDROM
motors.
The MAE Jinx is made from CNC-cut 6mm black Depron-foam parts. The vibrant blackand-
yellow graphics are screen-printed onto the components.
IF YOU’RE IN the mood for something
different, the Jinx from Model Airplane
Engineering (MAE) is definitely worth
trying. Its aquatic outline has the presence of
a shark/manta ray hybrid.
Come to think of it, swimming through
water is a lot like flying through air, less the
attributes of buoyancy. Given that this model
is made with the qualities acquainted with a
foamie (light enough to be nearly buoyant),
perhaps this arrangement of airplane and fish
has its positive points.
As of late, given the benefits of foam
construction techniques and lightweight
electric-power systems, kit designers have
been able to explore wilder aircraft concepts.
The Jinx employs many rare features that are
combined to create a model that a pilot can
appreciate from a number of perspectives.
To begin with, it is a twin-power-plant
design—a feature for which electric power is
well suited because the prospect of an
engine-out situation is virtually gone. The
motors are placed fairly close to the fuselage
centerline, which removes any chance of an
isometric thrust problem. The engine
nacelles’ vertical profile stabilizes engine
thrust and offers the benefit of lateral (sideforce)
stability.
The curved outlines make the Jinx stand
out next to any other model that may be at
the flightline. However, designer Jeff Krebs
purposely applied the design elements to
achieve handling qualities the novice to
expert pilot could appreciate.
For instance, the airplane’s tail surfaces
dominate the profile with an evil “shark”
attitude, but the displacement of area on the
elevators is located as close to in-line with
the motors as possible. The advantage is
better elevator-input authority during slow-
10sig2.QXD 8/24/06 9:26 AM Page 58October 2006 59
The Bluebird 306 servos are light and
strong. Most popular submicroservos will
fit into the precut servo openings. The Jinx is available as a stand-alone kit or as a complete package from MAE.
The Hitec 05 receiver reserves the fifth
channel for flap control. This way the
tiperons can also be programmed for flap
and air-brake controls.
The tiperons rotate around the 4mm
carbon-fiber-tube spar. The accurately
shaped hardware and linkage is provided
on a laser-cut 1/32 sheet.
speed (high-alpha) maneuvers. The
vertical fin’s dorsal design keeps the
rudder powerfully effective even though it
isn’t directly in line with the propeller
blast.
Observing the fuselage profile we can
see a cockpit canopy outline; lo and
behold, it’s not a fish after all. The
enormous canopy’s forward position
promotes lateral stability, not only at high
speed but also in knife-edge flight. In
addition, the long nose offers a place in
which to put the battery on this puffed-up
(that’s fish talk)-empennage design.
Looking at the airplane from the top, you
can see the manta ray outline in the shape of
the wings. The wide root area promotes lift
for 3-D maneuvers while the narrower wings
are left to employ this sport model design’s
“secret weapon.” The wing sections outboard
of the engine nacelles are designed as
tiperons; for roll control the entire
wingtips rotate around a carbon-fiber spar,
offering outrageous roll input authority.
Below: The Jinx requires only a light underhand toss to launch. With the motors at full
power, a learned pilot may just need to let go for the Jinx to climb out vertically.
Photos by Mark Lanterman and the author
10sig2.QXD 8/24/06 9:29 AM Page 5960 MODEL AVIATION
Test-Model Details
Motor (two): Westport Design 20T
CD-ROMs
Battery (one): 7.4-volt, 1250 mAh
or 11.1-volt, 700 mAh Li-Poly
Propeller (two): GWS 8 x 4 direct
drive or GWS 7 x 3.5 direct drive
Static draw: 7.1 amps
Motor output: 72 watts at 10.2 volts
Radio system: Hitec Optic 6
transmitter, Hitec Micro 05S receiver,
four Bluebird 306 microservos, two 6-
inch servo extensions, single Castle
Creations Thunderbird-9 ESC
Ready-to-fly weight: 9.2 ounces
Flight duration: Eight to 14 minutes
• Fast and easy to build with vibrant
screen-printed graphics
• Economical, efficient, powerful power
system
• Fun to fly with an impressive
performance envelope
Pluses and Minuses
+
- • None. (Honest!) Wait! Does fishy
count?
Type: RC sport flat-foam kit
Pilot skill level: Intermediate
Wingspan: 39 inches
Wing area: 275 square inches
Length: 31.5 inches
Weight: 8.5-9.5 ounces
Wing loading: 4.71 ounces per
square foot (average)
Power (recommended): Dual
brushless CD-ROM motor
Radio: Four channels minimum, four
submicroservos
Construction: Black Depron sheet
foam with carbon-fiber-tubing
reinforcement
Covering/finish: Preapplied,
screened two-color graphics
Price: $59.95
Specifications
leaves fuzzy edges on the foam, so I dressed
the outer edges of the parts using 180-grit
sandpaper and left the tab-and-notch gluejoint
areas as provided.
As instructed, I used UHU Creative
cement (also available from MAE) to
assemble the foam parts. This adhesive
works like rubber cement, where adhesive is
evenly applied to the contact areas and then
allowed a few minutes to tack-dry before
permanently joining them.
The process takes a bit longer than
assembly methods using foam-safe
cyanoacrylate. The benefit of the UHU is
that it’s as flexible as the Depron foam
when cured, whereas cyanoacrylate joints
are brittle.
Along with the four-page illustrated
instruction manual provided, the MAE Web
page has full-color photos of key areas to
complement the building process. I was
grateful to find those photos because the
directions regarding the tiperons were a bit
gray (pun intended; the illustrations in the
manual are in grayscale) to me.
The detailed photos cleared up all my
concerns, and the build sped along. I had the
Jinx ready to fly after roughly three relaxing
evenings of work.
I deviated from the instructions only
during the horizontal fuselage and wing
construction. While this assembly was flat I
advanced to the elevator installation and
hinged it to the stabilizer. I predicted that if
I installed the elevator after the vertical
portions of the fuselage were attached,
hinging would be awkward to complete
neatly.
The Jinx was a snap to build straight.
Because I ordered the recommended radio
accessories with the kit, everything was a
drop fit into the precut locations. I decorated
the laser-cut 1/32 plywood control horns with
black marker so they matched the black color
scheme; in addition, it gives them the hightech
look of carbon fiber.
Low-temperature hot glue holds the
servos in place. Velcro (included) is used to
mount the receiver in the tail, and the battery
Jinx on the Bench: This model is available
direct from MAE as a stand-alone kit,
packaged with “plug-and-fly” motors, or
bundled with everything but the receiver.
The company’s Web site is a one-stop
shopping experience.
I used all the accessories and equipment
recommended by the manufacturer, and
overall I’m extremely pleased with the
outcome. Unless you have an overflowing
parts drawer, you won’t go wrong with a
package purchase.
The Jinx has been engineered to a
practical size; a one-piece model with a
wingspan exceeding 40 inches is a pain to
transport. With that in mind, the Jinx
worked out to where it could use an
economical set of brushless motors.
The Westport Design power plants are
essentially CD-ROM motors built to suit
electric-powered aircraft. The motors that
are recommended for the Jinx have been
wound with 20 turns of 25-gauge wire in
the WYE parallel termination.
The motors don’t need a gearbox since
they’re outrunners, and the way my set was
packaged, with the lead wiring in place, all
that was left for me to do was connect the
speed control. That’s right; a single
Thunderbird-9 ESC is effectively
controlling both motors on my Jinx.
The builder has the option of employing
a two- or three-cell Li-Poly battery setup.
To keep the Westport motors within their
12-amp output range, GWS direct-drive
propellers are 8 and 7 inches respectively.
I fly many two-cell systems in this
foamie class. I test-flew this model with
that setup and experienced satisfying
performance. I tried the three-cell system
too because it was reported to give
“zippier” performance (which it did). It’s
nice to have options.
The kit is neatly packed by hand. The
CNC router-cut parts are taped to a rigid
cardboard sheet so the screen-printed parts
are less likely to be damaged. The router
as far forward as possible. Just enough music
wire is provided to make straight pushrods.
My pushrods were assembled as two pieces
joined with heat-shrink tubing and
cyanoacrylate.
With the servos so close to the control
surfaces, there’s almost no flex in the control
linkage. To get the 45°-70° of control throw
permitted in the ailerons, it might be
necessary to use the extra-long servo arms
made by Du-Bro (items 930 through 933). I
used the longest arm included with the
Bluebird 306 servos.
Low rate control was programmed with
half the maximum available throw. On high
rates the elevator and rudder deflect
approximately 50° each. The tiperons rotate
roughly 35° (which is plenty for a blinding
roll rate).
Exponential was programmed into the
high rates to soften the control-stick feel
around neutral. The recommended 70%
setting seemed appropriate and proved to
work well.
Jinx in the Air: The model’s lack of
undercarriage requires a hand launch and a
soft place to land. I first flew it with the twocell
Li-Poly battery and 8 x 4 propellers. An
underhand toss was all it needed for a safe
launch.
More than enough power was available to
accelerate straight up from a hovering
standstill. The Jinx’s WOT (wide-openthrottle)
speed was comfortable with half
throttle used for cruising and full throttle for
up-lines and emergency rescue (read obstacle
avoidance).
I have to admit that the Jinx is sensitive to
control-surface inputs. Some might call it
“twitchy”; I prefer to use the word “capable”
when describing its flying qualities.
This is a capable 3-D flier—probably the
most capable twin-motor aircraft I’ve ever
flown. Its agility quickly builds pilot
confidence, encouraging you to fly the
aircraft into tumbling maneuvers that seem
to defy gravity and imagination.
Almost the only handicap the Jinx has is
its rudder effectiveness while in a hover.
The propeller blast just can’t touch the
10sig2.QXD 8/24/06 9:29 AM Page 60rudder, so yaw control isn’t as responsive as
with a foamie with a single motor mounted in
the nose.
I could hover the Jinx after some practice,
but it reminded me of what a fish looks like
when it’s pulled from the water, with its tail
(or rudder in this case) flapping wildly
behind.
If rolling fast is your thing, the Jinx will
never fail to please. I thought my Ultra Stick
with its quadruple-aileron feature had a fast
roll rate; the Jinx is blinding. Of course, the
aileron response and roll rate are a product of
whatever the model’s airspeed is at the time.
The most crowd-pleasing maneuver I’ve
done so far is a stunt called the Blender
Bender (which I first saw on the MAE Web
site video page). After climbing to altitude,
point the Jinx straight down and pull the
throttle back to idle. With full aileron input,
the Jinx appears to drill itself down through
the air.
As the ground closes in and the roll rate
seems to be the most intense, quickly apply
full down-elevator and rudder. The Jinx stops
so fast, it’s almost as if it hits an invisible
floor. Finally, with the controls held at the
limits, smoothly add throttle back in so the
Jinx can perform rolling tumbles in a circle
with no further loss of altitude.
Of the two- and three-cell power
configurations, I’m happier flying the Jinxwith the faster 11.1-volt battery. The extra
zip the motors give turning at higher speeds
picks up the pace for air-show antics. The
Jinx will hover better using larger 8 x 4
propellers; the larger thrust area improves
control effectiveness. So for slow-speed
maneuvers (Harriers and the like), the twocell
power configuration is the better choice.
One other optional setup to play with is
flaperon control. With each aileron
connected on separate channels, they can be
mixed to function as flaps.
Not that the Jinx needs this input to slow
down or land, but the fun part is mixing the
flap control in with the elevator. When you
slave the flaps to the elevator, often regarded
as the air-brake function, whenever elevator
is used, an allotted amount of flap moves
with them.
The tiperons rotate back when upelevator
is applied and forward with downelevator.
I can turn the mix on and off, only
using the function to perform tight loops,
tumbles, and 50°-85° high-alpha passes.
The Jinx is a blast! It’s easy to gather a large
collection of foamies quickly. As much fun
as they can be to play with, many of them fly
alike.
An active RC pilot looks for something
different. The Jinx is distinctive in looks and
performance, including a bag of tricks that
won’t fail to surprise. MA
Michael Ramsey
Edition: Model Aviation - 2006/10
Page Numbers: 58,59,60,62
58 MODEL AVIATION
Park View: Model Airplane Engineering Jinx
MICHAEL RAMSEY
An RC electric
park flyer with
twin motors and
a twist or two
This is a twin-motor model that excels in
3-D performance. It’s extremely agile but
also predictable.
The Jinx is easy to assemble since the parts are interlocking with alignment tabs built in.
The greatest elevator area is located directly behind the motors.
Hidden on the underside is the Castle
Creations Thunderbird-9 brushless ESC
that perfectly operates two Westport CDROM
motors.
The MAE Jinx is made from CNC-cut 6mm black Depron-foam parts. The vibrant blackand-
yellow graphics are screen-printed onto the components.
IF YOU’RE IN the mood for something
different, the Jinx from Model Airplane
Engineering (MAE) is definitely worth
trying. Its aquatic outline has the presence of
a shark/manta ray hybrid.
Come to think of it, swimming through
water is a lot like flying through air, less the
attributes of buoyancy. Given that this model
is made with the qualities acquainted with a
foamie (light enough to be nearly buoyant),
perhaps this arrangement of airplane and fish
has its positive points.
As of late, given the benefits of foam
construction techniques and lightweight
electric-power systems, kit designers have
been able to explore wilder aircraft concepts.
The Jinx employs many rare features that are
combined to create a model that a pilot can
appreciate from a number of perspectives.
To begin with, it is a twin-power-plant
design—a feature for which electric power is
well suited because the prospect of an
engine-out situation is virtually gone. The
motors are placed fairly close to the fuselage
centerline, which removes any chance of an
isometric thrust problem. The engine
nacelles’ vertical profile stabilizes engine
thrust and offers the benefit of lateral (sideforce)
stability.
The curved outlines make the Jinx stand
out next to any other model that may be at
the flightline. However, designer Jeff Krebs
purposely applied the design elements to
achieve handling qualities the novice to
expert pilot could appreciate.
For instance, the airplane’s tail surfaces
dominate the profile with an evil “shark”
attitude, but the displacement of area on the
elevators is located as close to in-line with
the motors as possible. The advantage is
better elevator-input authority during slow-
10sig2.QXD 8/24/06 9:26 AM Page 58October 2006 59
The Bluebird 306 servos are light and
strong. Most popular submicroservos will
fit into the precut servo openings. The Jinx is available as a stand-alone kit or as a complete package from MAE.
The Hitec 05 receiver reserves the fifth
channel for flap control. This way the
tiperons can also be programmed for flap
and air-brake controls.
The tiperons rotate around the 4mm
carbon-fiber-tube spar. The accurately
shaped hardware and linkage is provided
on a laser-cut 1/32 sheet.
speed (high-alpha) maneuvers. The
vertical fin’s dorsal design keeps the
rudder powerfully effective even though it
isn’t directly in line with the propeller
blast.
Observing the fuselage profile we can
see a cockpit canopy outline; lo and
behold, it’s not a fish after all. The
enormous canopy’s forward position
promotes lateral stability, not only at high
speed but also in knife-edge flight. In
addition, the long nose offers a place in
which to put the battery on this puffed-up
(that’s fish talk)-empennage design.
Looking at the airplane from the top, you
can see the manta ray outline in the shape of
the wings. The wide root area promotes lift
for 3-D maneuvers while the narrower wings
are left to employ this sport model design’s
“secret weapon.” The wing sections outboard
of the engine nacelles are designed as
tiperons; for roll control the entire
wingtips rotate around a carbon-fiber spar,
offering outrageous roll input authority.
Below: The Jinx requires only a light underhand toss to launch. With the motors at full
power, a learned pilot may just need to let go for the Jinx to climb out vertically.
Photos by Mark Lanterman and the author
10sig2.QXD 8/24/06 9:29 AM Page 5960 MODEL AVIATION
Test-Model Details
Motor (two): Westport Design 20T
CD-ROMs
Battery (one): 7.4-volt, 1250 mAh
or 11.1-volt, 700 mAh Li-Poly
Propeller (two): GWS 8 x 4 direct
drive or GWS 7 x 3.5 direct drive
Static draw: 7.1 amps
Motor output: 72 watts at 10.2 volts
Radio system: Hitec Optic 6
transmitter, Hitec Micro 05S receiver,
four Bluebird 306 microservos, two 6-
inch servo extensions, single Castle
Creations Thunderbird-9 ESC
Ready-to-fly weight: 9.2 ounces
Flight duration: Eight to 14 minutes
• Fast and easy to build with vibrant
screen-printed graphics
• Economical, efficient, powerful power
system
• Fun to fly with an impressive
performance envelope
Pluses and Minuses
+
- • None. (Honest!) Wait! Does fishy
count?
Type: RC sport flat-foam kit
Pilot skill level: Intermediate
Wingspan: 39 inches
Wing area: 275 square inches
Length: 31.5 inches
Weight: 8.5-9.5 ounces
Wing loading: 4.71 ounces per
square foot (average)
Power (recommended): Dual
brushless CD-ROM motor
Radio: Four channels minimum, four
submicroservos
Construction: Black Depron sheet
foam with carbon-fiber-tubing
reinforcement
Covering/finish: Preapplied,
screened two-color graphics
Price: $59.95
Specifications
leaves fuzzy edges on the foam, so I dressed
the outer edges of the parts using 180-grit
sandpaper and left the tab-and-notch gluejoint
areas as provided.
As instructed, I used UHU Creative
cement (also available from MAE) to
assemble the foam parts. This adhesive
works like rubber cement, where adhesive is
evenly applied to the contact areas and then
allowed a few minutes to tack-dry before
permanently joining them.
The process takes a bit longer than
assembly methods using foam-safe
cyanoacrylate. The benefit of the UHU is
that it’s as flexible as the Depron foam
when cured, whereas cyanoacrylate joints
are brittle.
Along with the four-page illustrated
instruction manual provided, the MAE Web
page has full-color photos of key areas to
complement the building process. I was
grateful to find those photos because the
directions regarding the tiperons were a bit
gray (pun intended; the illustrations in the
manual are in grayscale) to me.
The detailed photos cleared up all my
concerns, and the build sped along. I had the
Jinx ready to fly after roughly three relaxing
evenings of work.
I deviated from the instructions only
during the horizontal fuselage and wing
construction. While this assembly was flat I
advanced to the elevator installation and
hinged it to the stabilizer. I predicted that if
I installed the elevator after the vertical
portions of the fuselage were attached,
hinging would be awkward to complete
neatly.
The Jinx was a snap to build straight.
Because I ordered the recommended radio
accessories with the kit, everything was a
drop fit into the precut locations. I decorated
the laser-cut 1/32 plywood control horns with
black marker so they matched the black color
scheme; in addition, it gives them the hightech
look of carbon fiber.
Low-temperature hot glue holds the
servos in place. Velcro (included) is used to
mount the receiver in the tail, and the battery
Jinx on the Bench: This model is available
direct from MAE as a stand-alone kit,
packaged with “plug-and-fly” motors, or
bundled with everything but the receiver.
The company’s Web site is a one-stop
shopping experience.
I used all the accessories and equipment
recommended by the manufacturer, and
overall I’m extremely pleased with the
outcome. Unless you have an overflowing
parts drawer, you won’t go wrong with a
package purchase.
The Jinx has been engineered to a
practical size; a one-piece model with a
wingspan exceeding 40 inches is a pain to
transport. With that in mind, the Jinx
worked out to where it could use an
economical set of brushless motors.
The Westport Design power plants are
essentially CD-ROM motors built to suit
electric-powered aircraft. The motors that
are recommended for the Jinx have been
wound with 20 turns of 25-gauge wire in
the WYE parallel termination.
The motors don’t need a gearbox since
they’re outrunners, and the way my set was
packaged, with the lead wiring in place, all
that was left for me to do was connect the
speed control. That’s right; a single
Thunderbird-9 ESC is effectively
controlling both motors on my Jinx.
The builder has the option of employing
a two- or three-cell Li-Poly battery setup.
To keep the Westport motors within their
12-amp output range, GWS direct-drive
propellers are 8 and 7 inches respectively.
I fly many two-cell systems in this
foamie class. I test-flew this model with
that setup and experienced satisfying
performance. I tried the three-cell system
too because it was reported to give
“zippier” performance (which it did). It’s
nice to have options.
The kit is neatly packed by hand. The
CNC router-cut parts are taped to a rigid
cardboard sheet so the screen-printed parts
are less likely to be damaged. The router
as far forward as possible. Just enough music
wire is provided to make straight pushrods.
My pushrods were assembled as two pieces
joined with heat-shrink tubing and
cyanoacrylate.
With the servos so close to the control
surfaces, there’s almost no flex in the control
linkage. To get the 45°-70° of control throw
permitted in the ailerons, it might be
necessary to use the extra-long servo arms
made by Du-Bro (items 930 through 933). I
used the longest arm included with the
Bluebird 306 servos.
Low rate control was programmed with
half the maximum available throw. On high
rates the elevator and rudder deflect
approximately 50° each. The tiperons rotate
roughly 35° (which is plenty for a blinding
roll rate).
Exponential was programmed into the
high rates to soften the control-stick feel
around neutral. The recommended 70%
setting seemed appropriate and proved to
work well.
Jinx in the Air: The model’s lack of
undercarriage requires a hand launch and a
soft place to land. I first flew it with the twocell
Li-Poly battery and 8 x 4 propellers. An
underhand toss was all it needed for a safe
launch.
More than enough power was available to
accelerate straight up from a hovering
standstill. The Jinx’s WOT (wide-openthrottle)
speed was comfortable with half
throttle used for cruising and full throttle for
up-lines and emergency rescue (read obstacle
avoidance).
I have to admit that the Jinx is sensitive to
control-surface inputs. Some might call it
“twitchy”; I prefer to use the word “capable”
when describing its flying qualities.
This is a capable 3-D flier—probably the
most capable twin-motor aircraft I’ve ever
flown. Its agility quickly builds pilot
confidence, encouraging you to fly the
aircraft into tumbling maneuvers that seem
to defy gravity and imagination.
Almost the only handicap the Jinx has is
its rudder effectiveness while in a hover.
The propeller blast just can’t touch the
10sig2.QXD 8/24/06 9:29 AM Page 60rudder, so yaw control isn’t as responsive as
with a foamie with a single motor mounted in
the nose.
I could hover the Jinx after some practice,
but it reminded me of what a fish looks like
when it’s pulled from the water, with its tail
(or rudder in this case) flapping wildly
behind.
If rolling fast is your thing, the Jinx will
never fail to please. I thought my Ultra Stick
with its quadruple-aileron feature had a fast
roll rate; the Jinx is blinding. Of course, the
aileron response and roll rate are a product of
whatever the model’s airspeed is at the time.
The most crowd-pleasing maneuver I’ve
done so far is a stunt called the Blender
Bender (which I first saw on the MAE Web
site video page). After climbing to altitude,
point the Jinx straight down and pull the
throttle back to idle. With full aileron input,
the Jinx appears to drill itself down through
the air.
As the ground closes in and the roll rate
seems to be the most intense, quickly apply
full down-elevator and rudder. The Jinx stops
so fast, it’s almost as if it hits an invisible
floor. Finally, with the controls held at the
limits, smoothly add throttle back in so the
Jinx can perform rolling tumbles in a circle
with no further loss of altitude.
Of the two- and three-cell power
configurations, I’m happier flying the Jinxwith the faster 11.1-volt battery. The extra
zip the motors give turning at higher speeds
picks up the pace for air-show antics. The
Jinx will hover better using larger 8 x 4
propellers; the larger thrust area improves
control effectiveness. So for slow-speed
maneuvers (Harriers and the like), the twocell
power configuration is the better choice.
One other optional setup to play with is
flaperon control. With each aileron
connected on separate channels, they can be
mixed to function as flaps.
Not that the Jinx needs this input to slow
down or land, but the fun part is mixing the
flap control in with the elevator. When you
slave the flaps to the elevator, often regarded
as the air-brake function, whenever elevator
is used, an allotted amount of flap moves
with them.
The tiperons rotate back when upelevator
is applied and forward with downelevator.
I can turn the mix on and off, only
using the function to perform tight loops,
tumbles, and 50°-85° high-alpha passes.
The Jinx is a blast! It’s easy to gather a large
collection of foamies quickly. As much fun
as they can be to play with, many of them fly
alike.
An active RC pilot looks for something
different. The Jinx is distinctive in looks and
performance, including a bag of tricks that
won’t fail to surprise. MA
Michael Ramsey