RCU Review Hangar 9 F4U Corsair Electric Conversion
by: Greg Covey
gear mains and tailwheel
custom plastics and fiberglass parts
9’s ARF version of the famous F4U Corsair warbird legend
is in a class by itself. It features all the usual Hangar 9®
ARF amenities like top-quality balsa and ply construction, UltraCote®
covering and all necessary hardware. It also includes pre-installed
retracts that rotate 90 degrees as they tuck into the wings. Factor
in the phenomenal flight performance and other scale touches like
the pre-painted fiberglass cowl and authentic trim scheme and
it’s easy to see why this is destined to be one of the most
popular sport ARFs ever.
Corsair's most unique feature was the "bent" wing that
resembled an inverted Seagull. This was the result of a marriage
between the most powerful engine ever installed in a piston-engined
fighter and one of the biggest propellers in the world. This gull-winged
Navy fighter was so surprisingly powerful that it took months
before anyone was able figure out how to land it on a carrier.
It was the plane that won the air war in the Pacific.
more information and full scale specifications on the F4U Corsair,
visit the Aviation
History On-line Museum.
F4U Corsair .60 ARF
Available from: Horizon
Street Price: $264.99
in (165.7 cm)
in (122.6 cm)
Wing Area: 752
sq. in (4851.6 sq. cm)
LB (3.4-3.9 kg)
channels w/ 6 servos (glow), 5 servo (electric)
Recommended Engines: .61-.75
2-stroke; .91-1.00 4-stroke
4 Hitec HS-85MG "Mighty Micro" servos for rudder and
1 Hitec HS-75BB Retract servo
1 Hangar 9 1/7th scale US W.W.II Pilot (HAN8311)
2 18" servo extensions
1 servo "Y" adapter
usual, I wouldn't get any glow fuel near a classic like this,
so my e-conversion project will be using the new AXI
4130 direct drive brushless outrunner motor from Hobby
All the parts in my Hangar 9 Corsair looked great! Each item was
carefully packed in the box and arrived without any damage. After
my success with their AT-6 model, I knew that I would not be disappointed
with the F4U Corsair design! I
couldn't have built a kit this well with my best efforts!
wings, fuselage, and tail all came in perfect condition. They needed
no touchup with either an iron or heat gun. The cowl and canopy
were precut and pre-painted. Later, in the review, I'll be cutting
holes in the plastic mock radial head for air cooling. This is recommended
for either electric or glow power.
my Hangar 9 AT-6, the Corsair retract wells were not pre-installed.
This allowed me to inspect the retract mechanism and apply some
Locktite to the screws.
close up shots of the fuselage reveal the quality of construction
and covering detail that has made me a real Hangar 9 fan! The fuselage,
although light, was rock solid in strength.
that every part of the fuselage is rounded and sheeted with balsa
before covering. The tail slots and motor mount holes are pre-cut.
The canopy area is pre-finished and the cover pre-painted. Most
of the decals have been pre-applied but an additional sheet comes
with the kit to finish the scale appearance after the plane is built.
Hobby-Lobby was my one-stop source for all my e-conversion parts.
They had a wide selection of motors, props, connectors, batteries,
and radio equipment to choose from.
selected all plug-n-play components for my e-conversion like the
4130 motor, Graupner GR605360
6mm prop shaft adapter, and the Graupner GP315080
15x8, 3-blade prop. The prop, adapter, and motor shaft all fit together
To keep my Hangar 9 Corsair light, I used some Hitec radio components
from Hobby Lobby. My four HS-85 "Mighty Micro" metal gear,
ball-bearing servos provide 49oz/in torque and weigh only .77oz
or 1/2 the weight of a standard size Futaba S148 servo. That's a
3oz weight savings over standard servos.
I also used an Ultimate
BEC (or UBEC) and the Jeti ADVANCE 77-3P Opto-coupled ESC. The
nice part about the Jeti ESC is that it comes with the mating connectors
for the motor. It
also has programmable timing modes and a brake on/off mode that
i'll cover in detail later in the review.
UBEC is a state of the art switching regulator designed to convert
an input voltage from 5.5v to 35v DC into a regulated output voltage
of 5v to power your receiver and servos. The UBEC can deliver
a continuous current of 3amps and a peak short term output up
to 5amps. This is meant to handle power for up to 8 servos.
typical 4-cell receiver battery pack weighs 3.2oz so I saved 2.2oz
along with the added convenience of not having to worry about
re-charging another battery pack.
is the PM41001
Aluminum Motor Mount for AXI 41 Series Brushless Motors. This
mount allows you to attach the motor on the outside of the
firewall just like a glow engine mount. The three piece anodized
aluminum mount is adjustable for lengths from 3-1/4 to 3-3/4".
The front plate is pre-drilled for the large 41 series AXI
motors. The lightweight yet strong mount comes with screws
and nuts for attaching the front mount to the sides. It requires
4 bolts to attach to your firewall. I simply used the T-nuts
and screws supplied in the Corsair kit that were meant to
mount the glow engine brackets.
make the prop adapter extend to the correct 5-5/8"
distance from the firewall to the cowl opening, you simply
make two aluminum sheets that are 2" long. This extends
the motor shaft to the proper position.
reversed the center screw set (supplied with the mount)
so that the smaller head clears the rotating can.
Power System Wiring:
Before mounting the motor to the firewall, I wired everything up
so it was plug-n-play once installed.
supplied with the Jeti ESC are soldered onto the motor wires
wired power system is now "plug-n-play" ready
to install into the plane
pre-wired motor mounted with ease using the stock T-nuts
screws that came with
the Hangar 9 kit
aileron servo mounts allow for almost any size servo
The smaller size of the servo didn't matter with the mounting scheme
used on the Corsair wing for the ailerons. I extended my servo cables
using a 24" section of flat cable that I soldered myself. Alternatively,
servo extension cables can also be purchased from Hobby Lobby Int.
A little 5-minute epoxy held the supplied wooden blocks in place.
the longest servo arm available so that the snap "keeper"
when I thought it was perfect, I realized my servo arms were a
touch short. I cut out a small slice in the balsa to allow the
plastic keeper (not shown) to move just below the surface. Alternatively,
you may wish to try a longer set of arms for the aileron setup
than what is provided with the servo.
Mount and Painting:
Graupner 15x8 prop hole was opened just a little to allow
the adapter to fit
the tips yellow adds a nice scale touch to the finished
course, I also had to paint the prop tips to match my
rudder top. After noticing in several of my photos that
I had painted the tips of my prop on the backside as well
as the front, a fellow RCU scale enthusiast pointed out
that only front side was painted on the full scale warbirds.
Pilots found that looking at a yellow ring was quite distracting
Flight Servo Tester:
struggling a bit with my retracts on my Hangar 9 AT-6 Texan,
I finally got them the work great by bending the legs so
that they were vertical when landing. This required a good
deal of transmitter use and the receiver also needed to
be powered by a battery.
decided that for my Hangar 9 Corsair, I would purchase
an Astro Flight Servo Tester from Tower Hobbies for $20.
has been a great tool so far! I now use it on all my servos
when testing the linkage and throw range.
gear mains rotate 90° as they tuck into the wings
retracts on the Corsair rotate 90 degrees as they open and
close. It was fun just to watch as I studied the mechanism
and worked them manually from the control rod.
appeared to work fine and the one linkage piece that was
nylon in my AT-6 retract linkage was now metal in my Corsair
linkage. This made me happy because I felt it would make
it more robust.
that in the photos, you can see the string run through the
wing for extracting the aileron servo leads. A nice design
touch by Hangar 9. I choose to run the aileron servo wire
extensions first before installing the wheel wells.
retract servo is mounted with parts supplied in the
retract servo mounting parts are layed out on top of the
opening. I used a Hitec HS-75BB Retract Servo from Hobby
Lobby since it was about half the cost of the JR version.
Unlike the Hangar 9 AT-6 Texan where the wheel wells were
preinstalled, they arrive open on the Corsair. I consider
this a better approach because it allowed me to fully inspect
the retract mechanism and route the aileron servo wires
rod position was moved to the outside bellcrank
hole to increase travel
have discovered that even when using the longest
servo arm on the HS-75BB Retract servo, the travel
is not sufficient to lock the wheels in both directions.
moved the rod position on the belcrank from
the inner hole to the outter hole by moving
the quick link. In the photo, you can see the
scored metal where the stock position of the
quick link used to be.
With the extra travel, we can now adjust the
rod so that the mechanism pin goes all the way
to the end when the wheels are out and almost
all the way to the other end when the
wheels are retracted. Always adjust the rod
on the servo arm so that a full lock is obtained
when the wheels are out.
also bent the rod going to the servo arm for
a more favorable angle.
a slight bend in the gear mains allows them
to stand upright when extended and seat into
the wells better.
perfect retracted fit
in the well
found that by inserting a large Phillips screwdriver
into the gear mains spring loop that I could easily
bend the main gear rod so that it was perpendicular
with the ground by forcing the wheel end over.
This not only looked better but it provides greater
strength to the gear mains when landing and made
the wheels fully retract into the wells.
I attached the wheel well with servo tape but
you can alternatively glue it in place. The wheels
were a perfect fit! I had fun testing the retracts
for proper operation.
the elevator joiner before installing the horizontal
gluing the stabilizers into the fuselage, you need to
remove the covering for a better hold.
choose to fit my entire elevator together on the table
before installing the wire joiner in the fuselage. This
ensured an easy assembly once the horizontal stabilizer
was glued into position. After
finishing my tail section, the Corsair really started
to look great! The manual properly warns you about remembering
to insert the elevator joiner before gluing the horizontal
stabilizer, but, it fails to warn you about a critical
rudder assembly step.
not push the vertical fin all the way forward per
mounting the vertical stabilizer, the manual instructions
have you push it all the way forward. The instructions
fail to tell you that this is only needed to initially
install the tailwheel control rod for bending. Be
sure to move the fin back until the rudder lines up
with the tailwheel control rod for a bind-free fit.
that in the photo, my tailwheel rod is not flush with
the leading edge of the rudder since the fin is too
far forward. Be sure to slide the fin only enough
forward to provide proper alignment with the tail
wheel wire (or support bracket) that is not yet installed.
assembly required some special cutting to help alleviate
some of the binding since I did not push my vertical
fin back into position after gluing. It should still
work for a +- 30 swing until the binding becomes excessive.
completed tail assembly and orientation with
the main wing
Corsair starts to shape up when the tail section is
Hangar 9 Corsair is starting to shape up! The wing is
test fitted onto the fuselage and then used to help
check the stabilizer alignment during assembly.
rudder and elevator servos are mounted in the tail section
in pre-made bays meant for standard size servos.
smaller HS-85MG servos need additional
bay extension pieces made
receiver antenna is run outside the fuselage
through the rudder servo bay
make my smaller HS-85MG servos fit, I created some
small plywood pieces that extend one end of the bay
and level the other end. Note that I also needed to
extend my connector wires about 24" on both servos.
also used the rudder servo bay opening as an exit for
my receiver antenna. No need to drill any extra holes
in this beauty.
the rudder swing arm set screw is key to a proper
The rudder linkage assembled as easy as the elevator
linkage. Since the rudder and tailwheel are turned by
a swivel arm, it is important to file a flat spot on
the rod where the set screw tightens and use some Locktite
to keep it in place. The supplied snap keeper makes
for an easy attachment to the servo arm.
receiver for this project is the FS5 from FMA
The FS5, 5-channel Flight System receiver package
represents the leading edge in safe, reliable
radio controlled equipment. Equipped with new
DSR technology and free Viewer Software, the FS5
receiver protects your aircraft during every phase
of the flight!
unprecedented interference rejection, digital
servo support, failsafe operation, radio data
readout and other groundbreaking features in
a small package, the affordable five channel
FS5 works with the FM PPM transmitter you already
have (or your PCM transmitter set to PPM mode).
Digital Signature Recognition (DSR) technology
continuously guards against on-channel interference.
In the event of signal loss or
overwhelming interference,the FS5 instantly moves
servos to their pre-set failsafe positions that
are programmed using your transmitter and External
Switch/LED (or Viewer Software).
Before you take-off, the FS5 scans the airways
and detects if someone else is on your frequency
before you even turn on your transmitter. If there
are interfering signals, the FS5 warns you with
a bright LED light. This multi-function LED will
also check battery voltage and inform you if signal
loss was experienced during flight.
While you fly, exclusive DSR technology continuously
guards against interference. You just turn the
receiver on and the DSR is automatic. It analyzes
the data stream and automatically checks for:
The 605SB servo buffer can be added in-line
for each long wire run to the servo, if needed.
or negative shift
number of pulses (and stores this)
you land, the FS5 tells you how your radio system
performed during flight. Each FS5 receiver includes
free Viewer Software for extended, graphical
data readout. While the Viewer Software isn't
required for setting up the FS5, it is a great
tool for radio system troubleshooting!
my setup, the ailerons are tied together with
a "Y" adapter cable like Mitch suggested.
You don't need independent aileron controls on
the Corsair. I should also note that while the
FS5 can mask interference issues, you still need
to pay attention to such issues. After all, you
don't want a situation where you are failsafing
around the sky, right?
offers an excellent companion to receiver installation
in situations where you are using long aileron
extensions, etc. in an installation. The 605SB
servo buffer can be added in-line for each long
wire run to the servo. The addition of the FS5
Viewer software and Flight Recorder has given
R/Cers the ability to troubleshoot installation
and design issues we were never able to see
fly the FS5 with no buffers. When you land,
look at the LED, if it's blinking, it will blink
out the number of failsafe events you had during
the flight. Don't turn power off or the memory
will be cleared! Press the button on the FS5
3 times and it will then blink out the number
of bad frames you had during a flight. The objective
of course would be to install the buffers (at
the receiver) until you minimize failsafe events
(should be 0 if your radio is in good shape
and tuned properly), and/or a low number of
bad frames. This will provide you a very definitive
picture of RF performance.
FS5 is actually an extremely precise glitch
counter. Of course, if you have a real bad installation,
you may get several failsafe events and you
could run the counter on the bad frames to it's
max which is 256. A clean flight should be somewhere
in the neighborhood of 30 bad frames or less.
It takes 50 consecutive bad frames to go into
failsafe. Also, when you're counting bad frames,
long blinks = 10 bad frames and short blinks
= 1 bad frame. 10 long followed by 5 short would
might be surprised by how much you haven't been
able to "see" before this technology!
9 1/7th scale US WWII Pilot (HAN8311)
painted by Jaclyn Favro
was fortunate to have a rising young artist, Jaclyn Favro,
from the Disney Studios in Orlando paint my WWII pilot figure
for me. She used a scheme similar to my AT-6 pilot but added
some additional detail for a great looking scale touch to
modified MaxCim Charging Harness uses Dean's Ultra Connectors
again, I modified a MaxCim Charging Harness to use Dean's
Ultra connectors, a 40-amp ATO-style fuse, and a single
battery connection. My hope is that someday this type
of charging harness will be sold to R/Cers for easy recharging
of the battery packs in the plane. The ATO fuse moves
from the 'Operate' to the 'Charge' position to connect
the charge jack and disconnect the battery from the controller.
This assembly allows me to mount my wing once in the morning
of an R/C event and simply taxi into the pits for a recharge
after a proper cooling period. It is a true convenience.
drilled some extra holes for the motor wires in a position
that would not allow them to touch the spinning can and
give me the maximum length.
holes were drilled into the firewall to properly
position the motor wires.
inside wiring is neat and spacious. Only the battery
pack remains to be connected.
The motor plugs into the ESC and the ESC into the charging
harness. The Ultimate BEC is then tapped into the battery
connector to feed the receiver and servo 5v.
side wall control panel offers control and monitoring
control section outside the plane has a On/Off switch for
the receiver 5v coming from the UBEC output and the FMA
FS5 External Button/LED controls for monitoring interference
and voltage level.
modified MaxCim Charging Harness has a charge jack and
2 positions for the ATO-style fuse; Operate and Charge.
have used this setup in several glow-to-electric conversions
already and it provides the ultimate convenience.
touch up my exposed balsa from cutting holes, I discovered
that the Delta Ceramcoat Acrylics (#2089) Navy Blue paint
is a great color match for my Hangar 9 Corsair. The 16-color
set was purchased at Michael's (SKU #02 957 5056 0599)
The JETI Advance controllers are a great match
for the AXI outrunner motors. When using the AXI outrunners like
the 4130 on my Corsair, you can set the controller for Hard Timing
mode. Hard timing increases both the motor RPMs and current draw
by up to 20% over the default Soft Timing mode. Hard Timing is
recommended for all Model Motor's AXI outrunner motors, even for
the first flight.
also turn the BRAKE OFF on my JETI Advance controllers for all
my aerobatic planes and scale warbirds. On scale warbirds, you
do not want a sudden prop halt to jerk the plane into a possible
stall situation. This also seems to always happen when the plane
is downwind at low altitude. The free-running prop results in
a more graceful drop in power level. More often than not, you
can detect the power loss well before the motor is disabled.
program the JETI Advance controller, it is as simple as setting
your transmitter throttle channel to full, turning it on, powering
up the ESC and receiver, and listening for the appropriate beeps
before setting the throttle stick to low. The new settings will
not change after disconnecting the battery pack.
addition to automatic cutoff and programming of modes, the JETI
Advance controllers have temperature overload protection which
disables the motor when the temperature reaches 110 degrees C.
cutting out the mock rotary engine, it was glued to the fiberglass
cowl with epoxy.
finished cowl mounted on the fuselage with four screws into
the supplied wooden blocks that were sanded and glued to the
firewall. The motor fit perfectly behind the mock rotary engine
and the cutouts supplied plenty of fresh air for cooling the
decided to install my pilot after the maiden flight
so instead of gluing on the canopy, I made it removable
with Du-bro (#525) #2 x 3/8 Button Head Sheet Metal
my plane balanced at 4" from the leading edge (LE)
until I adjusted my flight pack
Corsair initially balanced at 4" behind the leading
edge (LE) with the 18 cells in two packs behind the firewall.
The proper starting balance point is 5" behind the
LE at the fuselage. I made a 2" adjustment to my
flight pack to "zero in" the CG.
aid in balancing my .60-size Corsair, I used the Great
Planes CG Machine. Note that the plane should be balanced
with the gear mains retracted as in normal flight conditions.
"Y" adapter allows two battery packs to
be connected in series
created a "Y" adapter from Dean's Ultra
plugs to connect my 10-cell pack and 8-cell pack together
in series. This makes it easy to upgrade to a single
Lithium pack at a later date.
two packs were taped together using duct tape. The
packs fit perfectly in a position under the receiver
tray so that only a few pieces of foam were needed
to hold them in place. I wrapped foam on the forward
side of the plywood former so that a hole was left
in the middle for the two packs.
the packs were held well by the foam wedged into the
sides, I also wrapped the connector wire from one
pack around the plywood receiver tray for additional
security. The Dean's connector was then held with
battery position shown for the 18-cells of CP2400SCR
will put the CG properly at 5" behind the leading
edge at the fuselage.
finished F4U Corsair is shown with the retracts up and
finished Corsair weights 152oz (9.5 lbs) RTF with 18-cells
I set the control surfaces to the throws recommended
in the manual. (±11° for ailerons and elevator,
±20° for rudder)
Corsair was finally ready to fly after passing the pre-flight
Corsair was ready to fly after fine tuning the retract
linkage a bit. The controls checked out, the throw range
was good, the power checked out and the prop ring told
us that it was go time!
prop ring told us that it was go time!
Corsair started down the runway with authority and the
heavy cross wind required full right rudder to keep
it on track. The tail had already lifted when it passed
me so my pilot, Lynn, pointed it slightly into the wind
the Corsair sped away into the sky, we silently watched
it in awe
realistic look of the Hangar 9 design was evident in
the bright sunlight
Corsair seemed to handle the wind very well. The long
wing chord provided enough lift to make it feel lighter
in flight than was expected at 9.5lbs.