Plane Talk: Easytiger Models Stealth EDF Fleet - 2010/03

52 MODEL AVIATION
MICHAEL RAMSEY
Plane Talk: Easytiger Models Stealth EDF Fleet
A shape previously recorded for the highest count of UFO sightings can now be a fun-fly
regular. This F-117 is easy to fly!
At a glance, the molded-foam model looks full scale; its low profile and faceted design are
obvious. Four included servos control the wing and tail.
+
• Plug-and-play advanced electricducted-
fan model of a modern
design.
• Excellent parts fit.
• Good finish and detail for EPS
molded foam.
• Servo-operated retracts, bombbay
doors, nose wheel steering.
• Totally prewired with necessary
extensions, reversed servos, ESC .
• Shock-absorbing landing gear
with tethered door covers.
• Ready to fly in one evening.
-
• Gear struts need thread lock to
prevent fault.
• Requires a 30C-40C battery to
realize full performance.
F-117 Pluses and Minuses
Model type: Receiver-ready EDF
RC
Skill level: Beginner builder,
intermediate pilot
Wingspan: 31.5 inches
Wing area: 570 square inches
Length: 45.5 inches
Weight: 42.3 ounces
Wing loading: 10.7 ounces/
square foot
Power (included): 70mm EDF
with 2850 Kv outrunner, 50 amp
ESC
Radio: Six channels (minimum),
nine servos (included)
Construction: Molded EPS foam,
plastic hardware, aluminum landing
gear
Covering/finish: Durable paint
finish with water-slide decals
Battery: 2200 mAh 4S PowerEdge
Li-Poly
Motor output: 1,000 grams of
thrust
Radio system: Graupner MX-16
transmitter, XPS eight-channel
receiver
Flight duration: Five to eight
minutes
Price: $259 (as tested)
F-117 Specifications and Details
EASYTIGER MODELS (ETM) calls many
of its aircraft “Black Projects,” for one
obvious reason: those particular designs are
painted black. It’s sleek, hip, and cool, not to
mention that it’s easy to touch up and
maintain.
The company also mimics the high-tech
impression that stealth aircraft make. Several
ETM models are representations of stealthy
jets, and this review features three of them.
The focus will be primarily on the F-117,
which we found to be the benchmark to date
of the company’s efforts.
In the sidebars, please check out the SR-
71 (our first ETM foam-jet experience) and
the F-35C that Jay Smith was hooked up
with. He and I agree that the F-35 (or F-22,
because of its similar planform) would be
No design secret is out of bounds
with today’s midsize EDF model
03sig2.QXD_00MSTRPG.QXD 1/25/10 1:17 PM Page 52
great for anyone who wanted his or her jet
to be a feature-rich and friendly first
electric-ducted-fan (EDF) aeromodeling
experience.
ETM imports its models from a number
of sources. A peek at the Web site reveals
that the company sells more than electric jets
and is pioneering in the realm of electric
Giant Scale.
The people at ETM are modelers, and
they seem great at handpicking good
products because they test each one (instead
of relying on factory hype). When factory
instructions are insufficient, ETM will
supplement, or in some cases (as with the
SR-71) redo, a manual.
The F-117 is a generation ahead of the
SR-71 that was tested less than a year before.
Not only is its manual a better attempt at
instruction, but the presentation, hardware,
and packaging were a concerted
improvement. If you’ve been talking to
people at ETM as I have, complimenting
and/or criticizing a product experience,
54 MODEL AVIATION
This airplane is so notorious for headaches (in the aeromodeling world), I felt that
if ETM made an RC version of it that was actually flyable, maybe the company had
something to offer a market that was already crammed with jet offerings.
This model assembles easily, and the electronics work great with the full-range
Spektrum radio that I used. ETM rewrote the manual for this design, and I found it to
be as entertaining as it was reassuring.
The SR-71 flies with a slight nose-high attitude, so some reflex in the ailevators is
needed to cruise hands-off; set them with close to 3° of up. Without exponential, the
controls can feel incredibly sensitive; 40% made the sticks friendly. Inverted flight is
possible but requires extra forward pressure because of the positive reflex.
The advantage I’ve found in flying from a paved runway is that retracts (especially
the nose gear) will live longer. I don’t run the Blackbird at wide-open throttle for the
entire flight, because I like to be kind to the twin 50-amp ESCs and single four-cell
battery.
This model has a violent stall that causes the nose to rise dramatically (a Cobra
maneuver). The condition is predictable, and recovery is quick but needs 20-30 feet of
altitude. The model flies slow enough that a stall can easily be avoided; therefore, it
can be landed without issue.
As do all jets, this one needs to be flown to the ground. Although flight time is
short, the thrill of
piloting an SR-71
is enormously
fulfilling. MA
—Michael Ramsey
Right: Nacelle cones were painted black to
match but are provided in red to aid
visibility.
The SR-71 is a cinch to pilot. Its powerto-
weight ratio is better than 1:1.
Receiver-Ready SR-71 Blackbird
Jets need to be flown to the ground. Easytiger’s are as
light as they can be, so that airspeed at landing is as
slow as possible and therefore easy.
evidence shows that they are listening.
The F-117 (F-35C or SR-71) is all foam,
but not every ETM jet offering is. Call these
models “foamies” if you will; this type of
construction has benefits and disadvantages.
Foam EDF aircraft are almost the lightest that
can be found.
We know that lightweight airplanes are
among the easiest to fly, which is an asset to
new modelers or when a complex airframe is
considered, such as the modern military jet.
Light weight also means that the aircraft will
accelerate faster; therefore, if a pilot does get
into trouble, a burst of power can help to
quickly get flying again.
However, the trouble with a lightweight
model is that it can be somewhat delicate. The
EPS foam used on ETM aircraft is
exceedingly stiff, but it stops being pretty
when it meets the abrasive asphalt runway or
the table corner in the workshop. But repairs
are simple to make; a can of Testors flat-black
spray paint can be the greatest spare part in
the field box.
I don’t think foam aircraft are designed to
go 200 mph, but I’m all right with that.
They’re devised more for close-in flight, tight
turns, and making the pilot look like a Top
Gun natural.
Foam airplanes feed the bug. And if the
illness stays, what a person learns with the
model will translate to the skills needed to fly
higher-performance jets. I’ll take a forgiving
aircraft with killer looks over a touchy
fiberglass screamer almost any day.
I’m still surprised by how well foam
models work, although I was concerned at
first about the absence of reinforcement that is
typically seen in aircraft (such as wing spars).
They are unnecessary.
Granted, if an airplane tumbling wingtipover-
nose down the runway is your thing,
then, yeah, I’d put in a spar. I have yet to
make an ETM wing fold or even bend—and
some of my landings have been hard.
The models’ parts that are not molded in
align well with creatively designed sockets.
These holes’ intricacy increases the gluing
area, so that joint failure, regardless of the
chosen adhesive, is significantly reduced.
Glue is included with the F-117, but ETM
doesn’t recommend its use for assembly
because of the long cure time required. The
parts’ fit is darn near perfect—so close that
the recommended five-minute epoxy mostly
squeezes out. This also means that the joint is
as light as can be.
The flat-black paint absorbs epoxy in a
chemical fashion (it practically bonds), so
little joint preparation is necessary. However,
roughing the intersections is never a bad idea.
Messy, epoxy-packed joints make the flatblack
paint shine, but you can clean those with
rubbing alcohol without fear of damaging the
paint. Shiny parts on a stealth model don’t
look right.
Foamie jets such as the F-117, F-35, and
SR-71 can be built in one short evening (when
using five-minute epoxy). All of the wiring is
complete and is finished in such a manner that
a basic (noncomputer) radio would be
sufficient.
Specifications
Wingspan: 29.5 inches
Length: 47.5 inches
Wing area: 380 square inches
Flying weight: 34 ounces
Servos: Five microunits (included)
Power: Twin 64mm fans with 4300 Kv
motors and 50-amp ESCs
Total thrust: 42.3 ounces
Battery required: One 2200 mAh,
14.8-volt 20C Li-Poly
Radio required: Five-channel
transmitter; five-channel, full-range receiver
Flight duration: Two to three minutes
Price: $289
03sig2.QXD_00MSTRPG.QXD 1/25/10 1:34 PM Page 54
The F-117 bomb-drop feature offers a
dimension of the scale flying experience
that was previously limited to much more
expensive models.
March 2010 55
The full-scale F-35 Lightning II is a fifth-generation, single-seat, single-engine,
multirole stealth fighter. The role of the ETM version is fun! Don’t let the fact that
this is a jet scare you away; this one is easy to build and fly.
The parts count is low, and all of the radio gear comes installed, ready to be
connected to your receiver of choice. All leads are marked and follow the
Hitec/Futaba channel assignments.
I put the F-35C together in a day and spent the majority of that time waiting for the
epoxy to cure. Since the canopy needs to be installed, I added a scale F-35 profile
pilot and scale instrument cockpit before adhering it.
This jet requires a 4S 2100-2200 mAh battery; I used a TrueRC 25C unit that fit
nicely in the battery compartment behind the cockpit. The CG was within 1mm of
what the manual recommended.
The Lightning can fly quite slowly and stably, thanks to its lifting body design.
The full-flying stabilizer provides plenty of authority on the elevator and can be
adjusted, as can the ailerons, to suit your comfort level.
ETM’s F-35C is loaded with features, such as retracts, steerable nose wheel, and
easy-to-access battery hatch. Add to that its attractive finish and forgiving flight
characteristics, and you
have a compelling
reason to release your
inner jet jock. MA
—Jay Smith
[email protected]
Tons of wing area makes this aircraft a
floater. The red missiles are optional.
The F-35C is friendly to fly and makes a
great first jet.
Receiver-Ready F-35C Black Lightning II
Every series of Y harnesses used to link
the twin elevator, aileron, and retract servos
runs to the receiver compartment, where
individual prelabeled leads are ready to
connect to the receiver of choice.
A full-range receiver is the best for any
jet. I used the Graupner MX-16 radio that
has frequency technology, which is
available from Xtreme Power Systems
(XPS). Its eight-channel receiver fits
snugly into the radio compartment under
the magnetically sealed canopy. The
receiver is nice because it has only one
radial antenna.
Wired in series with the 50-amp ESC is a
7-amp BEC. I understand that this particular
BEC was specially selected for the F-117
because of its nine-servo load, which could
get perceptively demanding.
The F-117 comes with decent
instructions in the form of a full-color, 14-
page booklet. The photos tell most of the
story, which includes assembly as if the
customer had purchased the ARF—so you
get to see how the model went together.
What is unclear in the book is the
control-linkage geometry (which holes the
pushrods connect). I made sure that the
linkage ratio was near 1:1. Testing the radio
proved that 100% travel limits were
reasonable.
All of the linkages are adjustable, and the
9-gram microservos are centered and glued
to the molded sockets. They’re all black, so
they match the rest of the model.
One of the retract servos is a reverse type,
which makes radio setup easy. My aircraft’s
retract-servo limits needed to be increased to
150%, to ensure that stops up and down
were reached.
Screw-lock connectors make any retractpushrod
adjustment easy. If these servos
“buzz,” they’ll constantly draw current and
overload the BEC; getting it right is easy.
The F-117’s retractable landing gear is
special in several ways. The formed wire
struts are pressed into aluminum sockets
within the mechanical retract. These sockets
also include a shock-absorbing spring; that’s
extra cool.
The gear doors are mounted with springloaded
hinges so that they open
automatically; a string tied to each door
snags the retracting strut and pulls it shut. To
ensure that the gear struts stay put, wick the
joint with green thread lock or thin CA.
The nose gear uses two servos: one for
retraction and the other for steering. A neat
thing about the steering servo is that it is also
wired with the forward-pointing landing
light.
Even though the model is supplied
receiver-ready, its components are
serviceable. Some might think of these
foamies as throw-away, but if a servo dies,
motor chokes, or ESC goes DOA, ETM has
made sure that they’re reparable or
replicable.
Molded channels enclose all of the
wiring, to keep things neat and out of the
critical airstream (such as the intake
ducting). Yes, the servos are glued in, but a
Specifications
Wingspan: 36.1 inches
Length: 43.1 inches
Flying weight: 37.0-38.1 ounces
Servos: Includes eight micro units
Power: 2750 Kv brushless motor, 50-
amp ESC
Thrust: 35.3 ounces
Battery required: 2200 mAh, 14.8-volt
20C Li-Poly
Radio required: Five-channel
transmitter; full-range, five-channel
receiver
Flight duration: Four to six minutes
Price: $179
03sig2.QXD_00MSTRPG.QXD 1/25/10 1:36 PM Page 55
56 MODEL AVIATION
The included dummy ordnances are
lightweight foam (they don’t hurt anything),
and they sort of fling out of the bomb bays.
Flying low and slow, actuate the bomb doors
close to the runway to fully appreciate the
effect. Add white or yellow tape if retrieving
the bombs proves to be difficult.
The F-117 grooves at high speed and
feels like a sport model to fly. Any forwardflight
maneuver that requires no rudder can
be performed. At slow speed, I noticed a tail
wiggle; this is a characteristic of many V-tail
aircraft. No control-authority loss was noted.
Landing is best done by establishing a
higher angle-of-attack cruise with the throttle
set at nearly 50% and the gear down. With
the throttle, altitude is managed while it’s
guided to the threshold of the runway.
A full stall is not required for landing,
because the automatic nose-high attitude
assures that the main gear touches first. The
shocks in the landing gear do a good job of
helping the model stick to the runway.
If you can’t avoid a crosswind condition,
it is possible to slip the F-117 down the
centerline (hold the upwind wing down)—
but avoid any crosswind faster than 10 mph.
I miss not having a flying rudder on my
foamie jets. Not only could point rolls be
better coordinated, but landing-approach
headings could be properly managed. On the
F-117, it wouldn’t be difficult to exchange
some of the wiring so that at least V-tail
mixing could be set up.
The success of my experience with ETM has
me permanently hooked on jets. In fact, it
might be time to seriously consider one of
those vectored-thrust models. Have a look at
the company’s Web site to see the other
unique jets that it has available. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
ETM
Box 869
New York NY 10116
(917) 971-3322
http://easytigermodels.com
Sources:
XPS
2440 N. Kiowa Blvd.
Lake Havasu City AZ 86403
www.xtremepowersystems.net
RC Accessory
(813) 765-0124
www.rcaccessory.com
Spektrum RC
(800) 338-4639
www.spektrumrc.com
TrueRC
(773) 203-8695
www.truerc.com
Other Published Reviews:
Model Airplane News: March 2010
small amount of leverage in the correct spot
(opposite the direction of throw) will pop
them out.
My F-117 came out a bit nose-heavy from
the indicated balance point with a PowerEdge
4S 2200 mAh Li-Poly battery from RC
Accessory. The battery’s weight is average,
but its output rating is high, at 30C (a benefit
to be noted later). It sits with breathing room
in the back of the battery compartment, and
the factory-mounted security strap is used
merely as a stop.
I like that the canopy latches with a
magnet, but I should have tugged on it
because the glue let go on the first flight. I
used epoxy to fix it later.
Flight: Jets seem to fly with a slight nosehigh
attitude. The faster they go, the lesser the
angle of attack. Knowing that the model will
fly nose-high is important when going to trim
it for a normal cruise.
The specified thrust is a bit less than the
flying weight. In the old days, a power-toweight
ratio of 0.65:1 was good; I expected
this F-117 to be speedy.
You can order the proper battery pack
from ETM; mine came without. EDF models
will never achieve their rated performance
without a good battery.
Evan Chapkis started the PowerEdge line
of Li-Poly batteries at roughly the time my F-
117 arrived. Knowing that a good-performing
battery did a world of good for the SR-71’s
thirsty motors, I ordered a test sample from
Evan’s company, RC Accessory.
The F-117 doesn’t offer a great deal of
ventilation for electronics, but the space does
breathe. A high-performance battery in a
high-draw application such as an EDF is the
smartest accessory for the money.
Every flight, hard or conservative, has
brought back the PowerEdge battery pack just
slightly warmed (near 90°). The 20C batteries
I tested come back exceeding 100° (except for
in the SR-71, which heats a pack to 120°).
The flight notes that follow can be extended
to the SR-71 and F-35C.
Because the F-117 rests on the ground
with a close-to-zero deck angle, it needs to be
hauled off of the runway on takeoff. This
becomes familiar after the first flight but can
surprise a test pilot and produce a stall.
Once the model pops off, establish a 25°
climb and bring up the gear. It helped greatly
to use 50% exponential on the steering
control.
The retracts “bang” into the wheel wells.
If your radio can slow the servo transition,
that action will look better, but it’s not
required. I have the control on a three-position
switch, so they have the impression of
moving more slowly.
The bomb-door control was actuated with
a button, and then I changed to a toggle
switch. Because the MX-16 radio’s switches
can be programmed to do anything, playing
with the functionality seemed like a healthy
exercise.
Without a headwind, the F-117 needs 30-
40 feet of runway. It can be off in 20 feet with
a 10 mph breeze. The elevator will need to be
trimmed with approximately 2° of up to trim
for cruise.
Altitude is easy to get with this model, but
its climb ability is limited. Stall testing
showed that a wiggle in wings precluded a
drop of the nose. My jet predictably stalled to
the left, followed by a shallow descending
turn. I noticed no violent tendencies, and
recovery was instant.
By design, the F-117 is a challenge to see
in the air—especially in profile. I found it
helpful to bank the wings now and then, to
confirm its flight path. If it gets bigger, I’m
sure it’s coming back toward me.
When a jet isn’t moving forward, it’s
falling. For the control surfaces to work, they
need good airflow. Always keep a touch of
power on, even during the landing approach.
If the model feels or looks “weird” at any
time when it’s moving at slow speeds, add
power to prevent a stall and then establish
attitude. A jet seldom feels worse when flying
faster.
Keep this aircraft close during the first few
flights, to get familiar with looking at its
unusual planform. I made three flights before
it looked normal, and that’s when I realized
that just because it looked “funny” didn’t
mean that something was wrong.
It was the same with the SR-71; I just had
to get used to it. And flying faster than cruise
speed ensured that it stayed controllable.
The bomb-drop feature set the F-117 apart
from others on the market. The application of
this feature tells me that this model’s
designers wanted to offer a product that went
beyond the flight-performance envelope and
offered something that was a little more fun.
03sig2.QXD_00MSTRPG.QXD 1/25/10 1:37 PM Page 56

52 MODEL AVIATION
MICHAEL RAMSEY
Plane Talk: Easytiger Models Stealth EDF Fleet
A shape previously recorded for the highest count of UFO sightings can now be a fun-fly
regular. This F-117 is easy to fly!
At a glance, the molded-foam model looks full scale; its low profile and faceted design are
obvious. Four included servos control the wing and tail.
+
• Plug-and-play advanced electricducted-
fan model of a modern
design.
• Excellent parts fit.
• Good finish and detail for EPS
molded foam.
• Servo-operated retracts, bombbay
doors, nose wheel steering.
• Totally prewired with necessary
extensions, reversed servos, ESC .
• Shock-absorbing landing gear
with tethered door covers.
• Ready to fly in one evening.
-
• Gear struts need thread lock to
prevent fault.
• Requires a 30C-40C battery to
realize full performance.
F-117 Pluses and Minuses
Model type: Receiver-ready EDF
RC
Skill level: Beginner builder,
intermediate pilot
Wingspan: 31.5 inches
Wing area: 570 square inches
Length: 45.5 inches
Weight: 42.3 ounces
Wing loading: 10.7 ounces/
square foot
Power (included): 70mm EDF
with 2850 Kv outrunner, 50 amp
ESC
Radio: Six channels (minimum),
nine servos (included)
Construction: Molded EPS foam,
plastic hardware, aluminum landing
gear
Covering/finish: Durable paint
finish with water-slide decals
Battery: 2200 mAh 4S PowerEdge
Li-Poly
Motor output: 1,000 grams of
thrust
Radio system: Graupner MX-16
transmitter, XPS eight-channel
receiver
Flight duration: Five to eight
minutes
Price: $259 (as tested)
F-117 Specifications and Details
EASYTIGER MODELS (ETM) calls many
of its aircraft “Black Projects,” for one
obvious reason: those particular designs are
painted black. It’s sleek, hip, and cool, not to
mention that it’s easy to touch up and
maintain.
The company also mimics the high-tech
impression that stealth aircraft make. Several
ETM models are representations of stealthy
jets, and this review features three of them.
The focus will be primarily on the F-117,
which we found to be the benchmark to date
of the company’s efforts.
In the sidebars, please check out the SR-
71 (our first ETM foam-jet experience) and
the F-35C that Jay Smith was hooked up
with. He and I agree that the F-35 (or F-22,
because of its similar planform) would be
No design secret is out of bounds
with today’s midsize EDF model
03sig2.QXD_00MSTRPG.QXD 1/25/10 1:17 PM Page 52
great for anyone who wanted his or her jet
to be a feature-rich and friendly first
electric-ducted-fan (EDF) aeromodeling
experience.
ETM imports its models from a number
of sources. A peek at the Web site reveals
that the company sells more than electric jets
and is pioneering in the realm of electric
Giant Scale.
The people at ETM are modelers, and
they seem great at handpicking good
products because they test each one (instead
of relying on factory hype). When factory
instructions are insufficient, ETM will
supplement, or in some cases (as with the
SR-71) redo, a manual.
The F-117 is a generation ahead of the
SR-71 that was tested less than a year before.
Not only is its manual a better attempt at
instruction, but the presentation, hardware,
and packaging were a concerted
improvement. If you’ve been talking to
people at ETM as I have, complimenting
and/or criticizing a product experience,
54 MODEL AVIATION
This airplane is so notorious for headaches (in the aeromodeling world), I felt that
if ETM made an RC version of it that was actually flyable, maybe the company had
something to offer a market that was already crammed with jet offerings.
This model assembles easily, and the electronics work great with the full-range
Spektrum radio that I used. ETM rewrote the manual for this design, and I found it to
be as entertaining as it was reassuring.
The SR-71 flies with a slight nose-high attitude, so some reflex in the ailevators is
needed to cruise hands-off; set them with close to 3° of up. Without exponential, the
controls can feel incredibly sensitive; 40% made the sticks friendly. Inverted flight is
possible but requires extra forward pressure because of the positive reflex.
The advantage I’ve found in flying from a paved runway is that retracts (especially
the nose gear) will live longer. I don’t run the Blackbird at wide-open throttle for the
entire flight, because I like to be kind to the twin 50-amp ESCs and single four-cell
battery.
This model has a violent stall that causes the nose to rise dramatically (a Cobra
maneuver). The condition is predictable, and recovery is quick but needs 20-30 feet of
altitude. The model flies slow enough that a stall can easily be avoided; therefore, it
can be landed without issue.
As do all jets, this one needs to be flown to the ground. Although flight time is
short, the thrill of
piloting an SR-71
is enormously
fulfilling. MA
—Michael Ramsey
Right: Nacelle cones were painted black to
match but are provided in red to aid
visibility.
The SR-71 is a cinch to pilot. Its powerto-
weight ratio is better than 1:1.
Receiver-Ready SR-71 Blackbird
Jets need to be flown to the ground. Easytiger’s are as
light as they can be, so that airspeed at landing is as
slow as possible and therefore easy.
evidence shows that they are listening.
The F-117 (F-35C or SR-71) is all foam,
but not every ETM jet offering is. Call these
models “foamies” if you will; this type of
construction has benefits and disadvantages.
Foam EDF aircraft are almost the lightest that
can be found.
We know that lightweight airplanes are
among the easiest to fly, which is an asset to
new modelers or when a complex airframe is
considered, such as the modern military jet.
Light weight also means that the aircraft will
accelerate faster; therefore, if a pilot does get
into trouble, a burst of power can help to
quickly get flying again.
However, the trouble with a lightweight
model is that it can be somewhat delicate. The
EPS foam used on ETM aircraft is
exceedingly stiff, but it stops being pretty
when it meets the abrasive asphalt runway or
the table corner in the workshop. But repairs
are simple to make; a can of Testors flat-black
spray paint can be the greatest spare part in
the field box.
I don’t think foam aircraft are designed to
go 200 mph, but I’m all right with that.
They’re devised more for close-in flight, tight
turns, and making the pilot look like a Top
Gun natural.
Foam airplanes feed the bug. And if the
illness stays, what a person learns with the
model will translate to the skills needed to fly
higher-performance jets. I’ll take a forgiving
aircraft with killer looks over a touchy
fiberglass screamer almost any day.
I’m still surprised by how well foam
models work, although I was concerned at
first about the absence of reinforcement that is
typically seen in aircraft (such as wing spars).
They are unnecessary.
Granted, if an airplane tumbling wingtipover-
nose down the runway is your thing,
then, yeah, I’d put in a spar. I have yet to
make an ETM wing fold or even bend—and
some of my landings have been hard.
The models’ parts that are not molded in
align well with creatively designed sockets.
These holes’ intricacy increases the gluing
area, so that joint failure, regardless of the
chosen adhesive, is significantly reduced.
Glue is included with the F-117, but ETM
doesn’t recommend its use for assembly
because of the long cure time required. The
parts’ fit is darn near perfect—so close that
the recommended five-minute epoxy mostly
squeezes out. This also means that the joint is
as light as can be.
The flat-black paint absorbs epoxy in a
chemical fashion (it practically bonds), so
little joint preparation is necessary. However,
roughing the intersections is never a bad idea.
Messy, epoxy-packed joints make the flatblack
paint shine, but you can clean those with
rubbing alcohol without fear of damaging the
paint. Shiny parts on a stealth model don’t
look right.
Foamie jets such as the F-117, F-35, and
SR-71 can be built in one short evening (when
using five-minute epoxy). All of the wiring is
complete and is finished in such a manner that
a basic (noncomputer) radio would be
sufficient.
Specifications
Wingspan: 29.5 inches
Length: 47.5 inches
Wing area: 380 square inches
Flying weight: 34 ounces
Servos: Five microunits (included)
Power: Twin 64mm fans with 4300 Kv
motors and 50-amp ESCs
Total thrust: 42.3 ounces
Battery required: One 2200 mAh,
14.8-volt 20C Li-Poly
Radio required: Five-channel
transmitter; five-channel, full-range receiver
Flight duration: Two to three minutes
Price: $289
03sig2.QXD_00MSTRPG.QXD 1/25/10 1:34 PM Page 54
The F-117 bomb-drop feature offers a
dimension of the scale flying experience
that was previously limited to much more
expensive models.
March 2010 55
The full-scale F-35 Lightning II is a fifth-generation, single-seat, single-engine,
multirole stealth fighter. The role of the ETM version is fun! Don’t let the fact that
this is a jet scare you away; this one is easy to build and fly.
The parts count is low, and all of the radio gear comes installed, ready to be
connected to your receiver of choice. All leads are marked and follow the
Hitec/Futaba channel assignments.
I put the F-35C together in a day and spent the majority of that time waiting for the
epoxy to cure. Since the canopy needs to be installed, I added a scale F-35 profile
pilot and scale instrument cockpit before adhering it.
This jet requires a 4S 2100-2200 mAh battery; I used a TrueRC 25C unit that fit
nicely in the battery compartment behind the cockpit. The CG was within 1mm of
what the manual recommended.
The Lightning can fly quite slowly and stably, thanks to its lifting body design.
The full-flying stabilizer provides plenty of authority on the elevator and can be
adjusted, as can the ailerons, to suit your comfort level.
ETM’s F-35C is loaded with features, such as retracts, steerable nose wheel, and
easy-to-access battery hatch. Add to that its attractive finish and forgiving flight
characteristics, and you
have a compelling
reason to release your
inner jet jock. MA
—Jay Smith
[email protected]
Tons of wing area makes this aircraft a
floater. The red missiles are optional.
The F-35C is friendly to fly and makes a
great first jet.
Receiver-Ready F-35C Black Lightning II
Every series of Y harnesses used to link
the twin elevator, aileron, and retract servos
runs to the receiver compartment, where
individual prelabeled leads are ready to
connect to the receiver of choice.
A full-range receiver is the best for any
jet. I used the Graupner MX-16 radio that
has frequency technology, which is
available from Xtreme Power Systems
(XPS). Its eight-channel receiver fits
snugly into the radio compartment under
the magnetically sealed canopy. The
receiver is nice because it has only one
radial antenna.
Wired in series with the 50-amp ESC is a
7-amp BEC. I understand that this particular
BEC was specially selected for the F-117
because of its nine-servo load, which could
get perceptively demanding.
The F-117 comes with decent
instructions in the form of a full-color, 14-
page booklet. The photos tell most of the
story, which includes assembly as if the
customer had purchased the ARF—so you
get to see how the model went together.
What is unclear in the book is the
control-linkage geometry (which holes the
pushrods connect). I made sure that the
linkage ratio was near 1:1. Testing the radio
proved that 100% travel limits were
reasonable.
All of the linkages are adjustable, and the
9-gram microservos are centered and glued
to the molded sockets. They’re all black, so
they match the rest of the model.
One of the retract servos is a reverse type,
which makes radio setup easy. My aircraft’s
retract-servo limits needed to be increased to
150%, to ensure that stops up and down
were reached.
Screw-lock connectors make any retractpushrod
adjustment easy. If these servos
“buzz,” they’ll constantly draw current and
overload the BEC; getting it right is easy.
The F-117’s retractable landing gear is
special in several ways. The formed wire
struts are pressed into aluminum sockets
within the mechanical retract. These sockets
also include a shock-absorbing spring; that’s
extra cool.
The gear doors are mounted with springloaded
hinges so that they open
automatically; a string tied to each door
snags the retracting strut and pulls it shut. To
ensure that the gear struts stay put, wick the
joint with green thread lock or thin CA.
The nose gear uses two servos: one for
retraction and the other for steering. A neat
thing about the steering servo is that it is also
wired with the forward-pointing landing
light.
Even though the model is supplied
receiver-ready, its components are
serviceable. Some might think of these
foamies as throw-away, but if a servo dies,
motor chokes, or ESC goes DOA, ETM has
made sure that they’re reparable or
replicable.
Molded channels enclose all of the
wiring, to keep things neat and out of the
critical airstream (such as the intake
ducting). Yes, the servos are glued in, but a
Specifications
Wingspan: 36.1 inches
Length: 43.1 inches
Flying weight: 37.0-38.1 ounces
Servos: Includes eight micro units
Power: 2750 Kv brushless motor, 50-
amp ESC
Thrust: 35.3 ounces
Battery required: 2200 mAh, 14.8-volt
20C Li-Poly
Radio required: Five-channel
transmitter; full-range, five-channel
receiver
Flight duration: Four to six minutes
Price: $179
03sig2.QXD_00MSTRPG.QXD 1/25/10 1:36 PM Page 55
56 MODEL AVIATION
The included dummy ordnances are
lightweight foam (they don’t hurt anything),
and they sort of fling out of the bomb bays.
Flying low and slow, actuate the bomb doors
close to the runway to fully appreciate the
effect. Add white or yellow tape if retrieving
the bombs proves to be difficult.
The F-117 grooves at high speed and
feels like a sport model to fly. Any forwardflight
maneuver that requires no rudder can
be performed. At slow speed, I noticed a tail
wiggle; this is a characteristic of many V-tail
aircraft. No control-authority loss was noted.
Landing is best done by establishing a
higher angle-of-attack cruise with the throttle
set at nearly 50% and the gear down. With
the throttle, altitude is managed while it’s
guided to the threshold of the runway.
A full stall is not required for landing,
because the automatic nose-high attitude
assures that the main gear touches first. The
shocks in the landing gear do a good job of
helping the model stick to the runway.
If you can’t avoid a crosswind condition,
it is possible to slip the F-117 down the
centerline (hold the upwind wing down)—
but avoid any crosswind faster than 10 mph.
I miss not having a flying rudder on my
foamie jets. Not only could point rolls be
better coordinated, but landing-approach
headings could be properly managed. On the
F-117, it wouldn’t be difficult to exchange
some of the wiring so that at least V-tail
mixing could be set up.
The success of my experience with ETM has
me permanently hooked on jets. In fact, it
might be time to seriously consider one of
those vectored-thrust models. Have a look at
the company’s Web site to see the other
unique jets that it has available. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
ETM
Box 869
New York NY 10116
(917) 971-3322
http://easytigermodels.com
Sources:
XPS
2440 N. Kiowa Blvd.
Lake Havasu City AZ 86403
www.xtremepowersystems.net
RC Accessory
(813) 765-0124
www.rcaccessory.com
Spektrum RC
(800) 338-4639
www.spektrumrc.com
TrueRC
(773) 203-8695
www.truerc.com
Other Published Reviews:
Model Airplane News: March 2010
small amount of leverage in the correct spot
(opposite the direction of throw) will pop
them out.
My F-117 came out a bit nose-heavy from
the indicated balance point with a PowerEdge
4S 2200 mAh Li-Poly battery from RC
Accessory. The battery’s weight is average,
but its output rating is high, at 30C (a benefit
to be noted later). It sits with breathing room
in the back of the battery compartment, and
the factory-mounted security strap is used
merely as a stop.
I like that the canopy latches with a
magnet, but I should have tugged on it
because the glue let go on the first flight. I
used epoxy to fix it later.
Flight: Jets seem to fly with a slight nosehigh
attitude. The faster they go, the lesser the
angle of attack. Knowing that the model will
fly nose-high is important when going to trim
it for a normal cruise.
The specified thrust is a bit less than the
flying weight. In the old days, a power-toweight
ratio of 0.65:1 was good; I expected
this F-117 to be speedy.
You can order the proper battery pack
from ETM; mine came without. EDF models
will never achieve their rated performance
without a good battery.
Evan Chapkis started the PowerEdge line
of Li-Poly batteries at roughly the time my F-
117 arrived. Knowing that a good-performing
battery did a world of good for the SR-71’s
thirsty motors, I ordered a test sample from
Evan’s company, RC Accessory.
The F-117 doesn’t offer a great deal of
ventilation for electronics, but the space does
breathe. A high-performance battery in a
high-draw application such as an EDF is the
smartest accessory for the money.
Every flight, hard or conservative, has
brought back the PowerEdge battery pack just
slightly warmed (near 90°). The 20C batteries
I tested come back exceeding 100° (except for
in the SR-71, which heats a pack to 120°).
The flight notes that follow can be extended
to the SR-71 and F-35C.
Because the F-117 rests on the ground
with a close-to-zero deck angle, it needs to be
hauled off of the runway on takeoff. This
becomes familiar after the first flight but can
surprise a test pilot and produce a stall.
Once the model pops off, establish a 25°
climb and bring up the gear. It helped greatly
to use 50% exponential on the steering
control.
The retracts “bang” into the wheel wells.
If your radio can slow the servo transition,
that action will look better, but it’s not
required. I have the control on a three-position
switch, so they have the impression of
moving more slowly.
The bomb-door control was actuated with
a button, and then I changed to a toggle
switch. Because the MX-16 radio’s switches
can be programmed to do anything, playing
with the functionality seemed like a healthy
exercise.
Without a headwind, the F-117 needs 30-
40 feet of runway. It can be off in 20 feet with
a 10 mph breeze. The elevator will need to be
trimmed with approximately 2° of up to trim
for cruise.
Altitude is easy to get with this model, but
its climb ability is limited. Stall testing
showed that a wiggle in wings precluded a
drop of the nose. My jet predictably stalled to
the left, followed by a shallow descending
turn. I noticed no violent tendencies, and
recovery was instant.
By design, the F-117 is a challenge to see
in the air—especially in profile. I found it
helpful to bank the wings now and then, to
confirm its flight path. If it gets bigger, I’m
sure it’s coming back toward me.
When a jet isn’t moving forward, it’s
falling. For the control surfaces to work, they
need good airflow. Always keep a touch of
power on, even during the landing approach.
If the model feels or looks “weird” at any
time when it’s moving at slow speeds, add
power to prevent a stall and then establish
attitude. A jet seldom feels worse when flying
faster.
Keep this aircraft close during the first few
flights, to get familiar with looking at its
unusual planform. I made three flights before
it looked normal, and that’s when I realized
that just because it looked “funny” didn’t
mean that something was wrong.
It was the same with the SR-71; I just had
to get used to it. And flying faster than cruise
speed ensured that it stayed controllable.
The bomb-drop feature set the F-117 apart
from others on the market. The application of
this feature tells me that this model’s
designers wanted to offer a product that went
beyond the flight-performance envelope and
offered something that was a little more fun.
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