66 MODEL AVIATION
Plane Talk: Hangar 9 Funtana 125 ARF
Shawn Rubush
Left: Shawn tightens two screws that hold
down an oversized canopy/hatch. The Tru-
Turn spinner is a 3-inch FAI-style anodized
red, specially cut to fit the Evolution 15 x 6
propeller.
Opposite page: This aircraft loves to fly,
thanks to the light wing loading and
tremendous wing area. A long tail
moment and large tail also help make it a
friendly fun-fly model.
The latest and
greatest edition
includes printed
covering
IN 2007 HaNgar 9 introduced the Funtana
X 100, which was built for 3-D and highalpha
flight. Now the company has an
improved, reworked version of the design.
The 125 version has such notable
features as printed covering in a distinct,
aggressive color scheme that is sure to
turn a few heads. Symmetrical-airfoil tail
surfaces were incorporated to improve the
model’s stability and flight performance.
The horizontal stabilizer and wing are
two-piece assemblies that bolt on with the
support of carbon-fiber tube spars.
The Funtana’s horizontal tail sections bolt
into recessed pockets, to ensure correct
alignment. Transporting or storing this
airplane is easier, because its alignment is
assured.
The canopy and top hatch assembly are
one piece; molded plastic forms the entire
structure, which is reinforced with a
framework of preinstalled laser-cut plywood.
The hatch is a nice touch of engineering that
not only allows easy access to everything in
the airframe, but it also has a great fit to the
fuselage. Only two 3 x 12 mm hex-head bolts
lock the hatch.
One other feature that stood out was that
during the factory assembly process, blind
nuts were preinstalled in the fuselage
wherever needed. Four blind nuts were also
installed in the fuselage to mount the engine
cowl.
Anyone who has had to locate blind nuts
anywhere by feel can understand the
significance of that courtesy. It also meant
that the mounting holes in the cowling were
located. I was happy about that, because I’ve
never mounted a prepainted cowl without
damaging it.
Having done a complete inventory and
inspection of all the parts, I realized that the
Funtana 125 does not include Side Force
Generators (SFG), which are referred to in the
manual. Then I realized that they were not
forgotten, but were an option that you can
purchase separately from Hangar 9 for
$24.95.
SFG are definitely on my list of items to
buy as soon as they become available. They
are also removable, to suit either 3-D or sportflying.
After an inventory of the supplied parts
and hardware and then a cursory read through
the manual, it was time to jump into the build.
But before starting this project, you have to
decide what power plant you will use.
The Funtana 125 has been designed for
two-stroke glow, four-stroke glow, fourstroke
gas, or electric (an E-flite Power 110EP
outrunner). I chose the Saito FA-125A
Golden Knight glow engine. There is nothing
like the meaty sound of a four-stroke.
Along with the power choices, you have
two options for setting up the ailerons; one
requires the use of two digital servos, a Y
harness, and one 6-inch servo extension. No
transmitter mixing is required.
The second choice requires the use of two
digital servos, two 3-inch extensions, and two
6-inch extensions. However, mixing is
required.
Knowing that I would be setting up the
Funtana 125 with a Spektrum DX7
transmitter and Spektrum AR7000 receiver, I
chose the latter aileron arrangement. But the
choices don’t end there; you also have three
elevator options.
1. Requires the use of one digital servo
and one reverse digital servo. No mixing
required.
2. Requires the use of two digital servos
and two 18-inch extensions. Mixing is
required.
3. Requires two digital servos and either a
Y harness or JR MatchBox servo matching/
power system.
I selected the second option. With a DX7,
programming using P-mix 5 or 6 allows the
elevator servos to have set endpoints and
offset independently. But, more important, the
master (elevator)-channel trim lever works
both channels in unison. This way, while
flying, the model can easily be trimmed for
level flight.
With all of my decisions made, it was time
to turn the page and begin the fun.
Construction: Initial steps involve installing
rudder and elevator servos. Using the
recommended JR DS9411 digital servos, I
found the elevator and rudder servo openings
to be too large lengthwise, leaving no margin
for error on the screw-hole locations.
If not centered with the utmost care, you
would be left with no material on either end
into which the mounting screws could be
inserted. Hardening screw holes with CA is a
must. Unfortunately the openings for the
ailerons were too large as well.
A simple solution was to install 1/16
plywood supports under the balsa wing
sheeting on both ends of the servo, to reduce
the opening, and then place balsa pieces on
top of the extended plywood to be flush with
the existing wing sheeting. The resulting
mounting area is double the original
thickness, providing a rock-solid mount.
After installing the servos in their
respective positions, the only electronics that
remained were the receiver, battery, and
switch. Note which switch you are using. The
Funtana 125 is designed for various power
combinations.
Three places are premade in the fuselage
to mount the switch. Which one you use
depends on what mode of power you choose.
Hinging control surfaces is
straightforward; the covering was well done,
with the exception of a few wrinkles here and
there. After the parts were acclimatized, I
used a covering iron to rework the UltraCote.
The printed covering on the wing and tail
surfaces required a bit more heat to achieve a
wrinkle-free finish.
Be careful not to overheat or overwork the
printed surfaces. Even with a new sock on the
covering iron, the printed covering had a
tacky feel that hindered my smoothly sliding
the iron.
As the manual states, sealing the control
surface hinge gaps is necessary to prevent
flutter on large control surfaces, not to
mention improved stability in high-alpha
flight. I used white Hangar 9 UltraCote to
match the covering.
Although not required, I sealed both sides
of all the hinges, simply because cleanup is
easier and it prevents fuel-soaked hinges.
After quickly installing the landing gear,
the engine is installed on the included
beams—or the standoff motor-box assembly
is used for the electric option. There is a
template in the back of the manual, in case
you decide to go gas, specifically the Saito
FG-20.
The recommended 90° exhaust elbow for
the Saito 125 muffler is incorrect in the
manual. The elbow part that Saito 125 users
need is SAI125A140.
With the engine properly mounted in its
new home, it was time to cut the holes in a
shiny new fiberglass engine cowl. Following
the steps provided in the manual, I used card
stock (poster board) to make templates for the
cutouts required to accommodate the Saito.
That template method produced one of the
cleanest-mounted engine cowls I had ever
August 2010 69
08sig3x.QXD_00MSTRPG.QXD 6/25/10 9:22 AM Page 69
August 2010 71
done. I had to admire the enclosed engine
with the sparkling gold rocker covers peeking
out, and I couldn’t help but smile. It was such
a simple idea; why didn’t I think of that?
Since I had jumped ahead and installed
the aileron servos, the only step remaining to
complete the wings was to attach the fillets.
Carbon-fiber alignment dowels were
preinstalled in the fillets and wing panels,
which made assembly and alignment a nobrainer.
Although identical in appearance, after
trial-fitting the fillets I improved the fit
between the wing and fuselage by switching
them from one side to the other. A dab of
epoxy sealed the deal on the wings, and the
build was almost complete.
Installing servo arms and control rods was
one of the last steps before finalizing the
build. I opted to use Du-Bro super-strength
long servo arms.
With all control rods in place, I
programmed the Funtana 125 to have the
factory-recommended high and low rates
specified in the manual. I put approximately
40% exponential on low rates and 60%
exponential on high rates as a starting point.
The instructions are to mount the battery
under the wing tube. I found that this left the
model tail-heavy. Not wanting to add more
weight than necessary, I moved the battery
forward to the left side of the fuselage, to put
the CG 167mm behind the wing LE.
Flying:With the engine break-in procedure,
range check, and flight control check
complete, it was time to burn some fuel.
Initial taxi on the asphalt tarmac made it
evident that the Saito FA-125 had plenty of
power; only two clicks of throttle had the
Funtana moving quickly. Slightly tightening
the wheels would be in order to assure that
the landing would come to a halt.
Bringing up the throttle, the Funtana
smoothly lifted off in a short distance with
a solid feel. It usually takes me awhile to
work off the maiden-flight nerves and get
friendly with a new airplane, but I
immediately felt as if I had flown this
model forever. After a few test laps and
only one click of right rudder to trim it
out, it was time to see what it could do.
Inverted flight with the CG at 167mm
seems to reflect a neutral balance point; little
stick input is needed to maintain level flight.
On low rates the Funtana performs precisely
with no unwanted characteristics—perfect for
practicing precision maneuvers.
Moving on to high rates, the Funtana 125
can perform any 3-D maneuver you throw at
it, including Harriers, hovers, and Blenders.
Toward the end of the second flight, I
noticed a slight jitter, or wiggle, when
pushing over hard from inverted. It was
manageable, but I’ll check into it nonetheless;
it’s a sign of instability. Perhaps the SFG will
help.
That giant wing likes to fly. Every highalpha
maneuver out there still has a little
wing in there and, by design, the Funtana has
more than most. That wide-body fuselage
adds to the lifting area as well.
However, the Funtana gives it up more
than I’d like in knife-edge. A great deal of
throw in the rudder is needed to carry knifeedge
flight, and the more that is used, the
worse the model couples, typically pushing
toward the gear and perversely rolling. It
looks like I’ll be using some of the lowernumber
P-mixing in the DX7 to cure that.
The Saito 1.25 provides enough power to
stand the Funtana on its tail in a hover at
roughly 60% power. Approach to a Harrier
needs almost no power, even to arrest a
descent. The power combination is healthy,
and I can pull this model out of a hover in
style with 40% throttle waiting.
The Funtana 125 is an excellent wind
airplane. Yes, it does have ample wing to
make it a floater, but it also has lots of control
authority and oodles of power to loosen the
grip of any gust that comes along. Let’s face
it; a pretty flying day is going to be windy
more often than not.
My favorite maneuver to perform in the
wind with this aircraft is a Zero Roller. That’s
where the airplane continuously rolls without
gaining or losing altitude, has no ground
speed, and stays on heading. The model loves
it.
The Funtana 125 has quickly climbed the
list as one of my favorite airplanes. I can’t
wait to get the SFG, to see the difference in
knife-edge performance. MA
Shawn Rubush
[email protected]
Manufacturer/Distributor:
Hangar 9/Horizon Hobby
4105 Fieldstone Rd.
Champaign IL 61822
(800) 338-4639
www.hangar-9.com
Sources:
Saito
(800) 338-4639
www.saitoengines.com
Spektrum
(800) 338-4639
www.spektrumrc.com
JR
(800) 338-4639
www.jrradios.com
Tru-Turn
(281) 479-9600
www.truturn.com
Dave Brown Products
(513) 738-1576
www.dbproducts.com
E-flite
(800) 338-4639
www.e-fliterc.com
Du-Bro Products
(800) 848-9411
www.dubro.com
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