Plane Talk: Pacific Aeromodel Gee Bee Model Y - 2006/05

IF YOU’RE SEARCHING for a great-flying,
large-scale airplane with classic looks, you’ve
found it! This model transports you back to a
more leisurely era, in a time when the Golden
Age of Aviation was in its prime.
The Granville Brothers Gee Bee Model Y
Senior Sportster was not built to be a racer as
their other types R-1 and R-2 were. They
were intended to be easier to fly and
therefore built for promotional and company
business trips. Even so, the aircraft modeled
here (registration #NR718Y) was used to
race competitively and did well.
As I opened the box from Pacific
Aeromodel and saw the beautiful red-andwhite
covering job, the quality of the kit,
and the size of the airplane, the first thing I
thought was, Wow! Then I began having
thoughts of my scarf flapping in the breeze
as I flew off into the sunset. But we can’t
fly it if we don’t build it, so here goes.
Foreword: The instructions are in book
form with two pages of addendum. There
are some good photos and explanations
except for that darned dummy engine, but I
will get to that later.
I thought about purchasing a Saito 1.80 or
a Zenoah G-26 engine since both are shown
installed as examples in the instructions. I had
an old O.S. 1.20 four-stroke in my drawer, and
the manufacturer claims, under “Engines,”
that “The Gee Bee Y will fly very well with a
1.20 2-cycle or 4-cycle engine.” I decided to
put that recommendation to the test.
My biggest concern was that the model
would be tail-heavy with such a light engine
up front and all those servos in the tail. I
refuse to add useless weight (I guess that’s the
electric-power and 3-D flier in me), so I came
up with some interesting ways to solve this
and other problems that sprung up along the
way.
When I’m building a model I skim the
instructions and then assemble the airplane in
what I think would be the best order. For this
review I followed each step of the assembly
process in the manual.
This is a big model, and you should use
high-torque servos. The manufacturer calls for
a high-torque servo only on the rudder and
good-quality ball-bearing servos on the otherMay 2006 51
Hardwood extension blocks properly space
the engine from the cowl. Note the
author’s use of space for the throttle servo.
In a weight-shift effort Nick mounted the
receiver and glow-heat battery in a custombuilt
tray on the front of the firewall.
Wood support blocks need to be
positioned inside the front of the cowl to
mount the dummy radial. The engine
cutout at the bottom is shown.
Contents of the Pacific Aeromodel Gee Bee Y package. All the structures are covered
beautifully, and the hardware provided is complete.
The colors used for the trim scheme and its classic scale looks make this airplane stand out on a crowded flightline.
Flight photos by Mark Lanterman; others by the author
At high speed the Gee
Bee Y is rock solid and
handles smoothly. All
that is needed to
complete this image is
a 1/4-scale Williams
Bros. pilot figure.
The author made a special bracket for
transportation and storing the fuselage
on a wall. This way all the weight is not
resting on the muffler.
control surfaces. If you don’t have the
necessary servos, buy good ball-bearing
servos that have a high torque rating; it’s
money well spent.
The instructions also call for three 12-inch
and one 18-inch servo extension and two Y
connectors. I used four 18-inch extensions,
which allows me to plug my ailerons directly
into the receiver without the need for short
pigtails that are typically used on the receiver
for servo hookup.
Then I programmed the transmitter for
split elevators and activated the flaperon
control of the ailerons. A servo reverser is
unnecessary because of the servo placement
for the elevator. If you don’t have a computer
radio, Y-connectors will work fine to link
these servos.
The wing is made from two pieces joined
with an aluminum tube and alignment pin. It
is held together and to the fuselage with a
plywood tab and two hefty bolts. This
assembly feature makes transporting an 82-
inch wing much easier.
Assembly: Follow all the steps per the
instructions until you get to the section titled
“Assembling the Wings.” It’s much easier to
install the control horns before this point.
Follow the addendum and use the included
bolt-style horns. Install them through the hard
points in the ailerons.
I thought the pushrods were a bit small for
this size of model, but as short as they are they
should not present a problem if you fly in a
scalelike manner.
Make sure you follow the addendum for
the axle pads and wheel-pant installation. The
instructions tell you to cut through the bottom
flange at the slot so you can get the gear struts
inside. The review model came with the cuts
already in place, but this let the flanges warp.
I tried to straighten them and cracked the
paint on one of the gear covers in the process.
I corrected the problem by using my heat gun
on the inside to soften the fiberglass just
enough to straighten it. This worked great and
did not harm the paint in any way. With the
gear assembly finished, the wing was done.
At this point you have to decide what
engine you are going to use. Don’t forget to
change the fuel lines if you go with a gas
engine. The tubing supplied is silicone and is
incompatible with gasoline.
Since it’s shorter than anything of roughly
1.50 size, the 1.20 engine did not stick out far
enough to meet the thrust-washer setting of 6-
61/2 inches from the firewall. I used hardwood
blocks and spaced the engine mount out away
from the firewall almost 3/4 inch farther
forward.
Since it would have been difficult to mount
the throttle servo in the place recommended
because of linkage-angle complications, I
mounted the throttle servo to the front on the
firewall, between the new hardwood standoffs.
This solved the linkage setup and added more
weight to the front of the airplane.
To make sure I had all the usable weight
moved forward, I made a plywood battery
box and secured it to the front of the
firewall. I almost went with a pull-pull
system for the rudder, which would have
reduced the tail weight more.
The instructions clearly state that if you
leave the dummy radial engine off, you could
have overheating problems. Its purpose is to
direct cool air over the real engine.
The original instructions and the
addendum have two different methods of
attaching the dummy engine. Perhaps an
illustration would have helped here; it was
unclear to me exactly where the mounting
points were supposed to be.
I placed the cowl nose-down and laid
the included balsa blocks inside the cowl
with the flats facing up. I spaced them so
that when the dummy engine is placed
inside, the cutout is at the bottom (where
the real engine would be) and the
cylinder-head parts of the dummy engine
are resting on the flats of the four balsa
mounting points. With each cylinder lined
up between two respective cowl bumps I
glued everything together.
I did not trust the idle on the old fourstroke
mounted in the inverted position. I
installed an onboard glow system and
mounted the battery for it above the
receiver battery on the firewall. To
establish a perfect CG, all I needed was a
small brass spinner to finish the front end.
To fuel the aircraft I installed a Robart
Super Fueler (part 204) on the cowl betweensmaller cowl bump and blends in as if it were
made for this application.
The rest of the instructions were
straightforward. I had to replace two of the
clevises while hooking up the elevator
pushrods (they broke apart when opened).
Luckily I had some 2mm clevises left over
from another project.
The pushrods came made to length, and
even though I felt they were a bit light for a
1.20-size airplane I used them for the purpose
of the review and had no problems with them.
After setting up the radio I installed the
windshield. I put it on as instructed, but for
added security I reinforced the screw holes
inside the fuselage with scrap plywood. At
this point it was time for the most important
step: to recheck everything.
Flight Performance: When I arrived at the
field to meet the photographer I had my
reservations about the weather. It was foggy
and cloudy, with a fairly steady 15 mph wind
that was straight down the runway. I thought
to myself, “The show must go on.”
Flying in the wind doesn’t bother me, but I
knew I would not have any excess power with
only a 1.20 four-stroke up front; maiden
flights are always unnerving. I put the Gee
Bee together, checked the battery, and fueled
it up. After a range check we were ready to go.
The model taxied well through the grass
out to the awaiting runway. The wind was
blowing across the runway at roughly a 45°
54 MODEL AVIATION
angle and still at 15-plus mph. I reminded
myself of the saying “Sometimes they fly;
sometimes they die,” and then I gave it a
little rudder into the wind and hit the throttle.
To my surprise and delight the Gee Bee
went straight down the runway and lifted off
with authority. At the top of its climb it was
obvious that the manufacturer had not
exaggerated about this airplane flying very
well with only a 1.20. With this engine it
does a great tailslide at full throttle when it
just can’t climb any higher.
I climbed the model to a nice altitude,
performed a Split S, and came back over the
runway. Trim was almost dead-on, with only
a couple blips of down-elevator needed.
After several circuits over the field I brought
the airplane down for some photo passes and
some fun. Tracking was straight, and this big
Gee Bee was a pleasure to fly.
Inverted flight and knife-edge down on
the deck are not scale maneuvers for this
aircraft, but they sure are fun. After buzzing
the soybeans inverted and dipping a wingtip
as close as I could get in the beans, I took the
model back up for some stall tests. All it did
was drop the nose and mush forward.
I found no bad tendencies with this
airplane other than some roll coupling while
trying to perform knife-edge flight—a
maneuver that is always tough to perform
with an airplane that is not designed to fly
that way and with a fair amount of dihedral.
All normal scale maneuvers with this
aircraft were enjoyable, including spins. But
for flat spins you have to set up some high
rates. Landings are completely uneventful.
Just set up and fly this model back to the
runway before powering all the way back to
idle.
I liked flying this airplane so much that
after the photo shoot the photographer and I
filled the big Gee Bee up and each flew
through two more tanks of fuel. By that time
the clouds had departed and we shot a few
more pictures to show off how great this
classic old airplane looks