Snoopy and his Doghouse are going
through some checks. Snoopy is rough
carved and supervising the quad-frame-to-Doghouse mating. Note that beneath the
clock are the 2011 silhouettes of Snoopy
and Woodstock from the first Doghouse.
Photos by Walter Wallenborn, Ed Hanley, and Bill Paul
new design, the big questions are where to locate the CG and
how stable is the IFO. I usually build a small gliding model and
use it to determine a starting CG location, evaluate stability
issues, and experiment with flight control surface locations and
Because most of my designs are flown in front of large
crowds, safety is of utmost importance. As a rule, my air show
designs have the propellers shrouded within the IFO, making
human contact difficult. My designs tend to be lightweight,
weighing 2 to 4 pounds, and are capable slow-flying aircraft
that fly at maximum speeds of 30 to 40 mph. Some people
refer to them as flying kites.
Polystyrene or Depron foam are the primary building
materials in all of my designs. The foam shell is usually
reinforced with an internal carbon-fiber and/or dowel skeleton.
For unique shapes such as the Monster Can or R2-D2, I go to
a local foam-cutting company, FoamCo. It cuts beautiful, large
crown moldings and pillars out of polystyrene for high-end
homes and has a computer-controlled hot wire setup that can
carve 8 x 4 x 1-foot foam billets into any shape. The company’s
lightest foam is 1 pound per cubic foot and is what I use for all
of my modeling applications. Most cities have a foam company
with similar capabilities.
So let’s get back to Snoopy. As I sat in the theater, all I could
think about was a workable, quad-powered Doghouse. To this
day, I can’t recall the movie we watched!
With the roof’s sharp peak, the Doghouse lent itself to a +
copter configuration and a + configuration for the flight control
surfaces. I reasoned that the Doghouse could stand on end for
vertical takeoffs and landings and fly in horizontal, level flight
using the control surfaces for stability.
When I returned home, I went straight to You Tube to watch
the trailer for The Peanuts Movie over and over. I wanted my
Doghouse to be a perfect match to 3-D Snoopy’s. I figured the
Doghouse would weigh approximately 4 pounds ready to fly,
and ordered the necessary electronics for the build.
In the 4-pound all-up weight regime, I have had great success
with Hitec HS-225 servos, Cobra C-2213/12 motors, 40-amp
ZTW Spider Series ESCs, 5-amp HobbyKing BECs, and 7 x
4 APC propellers. This electronics combination can easily lift
4 pounds and complements the HobbyKing flight controller
well. Battery power is provided by two 3S 2,200 mAh 40C
LiPo battery packs. The remaining electronic requirements are a
standard six-channel receiver and transmitter.
To construct the Doghouse, I had FoamCo cut a 4 x
8-foot sheet of 1/2-inch thick, 1-pound foam and made
the Doghouse the largest size I could from the sheet. This
turned out to be slightly too large for easy storage and
transport. I also purchased a block of 1-pound foam that I
shaped into a Snoopy figure.
Knowing that Snoopy would sit on top of the Doghouse,
I designed the internal + quadcopter so that the overall
balance point of the house, on its end, would be at the
quad’s center. From my previous Doghouse experience,
I knew that the balance point of the house in horizontal
flight needed to be roughly 17% of the roof and bottom area
With foam in hand, I cut all of the Doghouse parts and
designed the structural skeleton required for strength and
rigidity. The skeleton also serves to support the battery tie-down
44 Model Aviation DECEMBER 2015