November 2006 35
A legendary
modeler’s equally
legendary design
translates into
a peppy RC
electric foam
aircraft
BY LEON SHULMAN
The Zoomer climbs out after making a
flyby for the camera. This model will be
available as an RTF from Polk’s Hobby.
“DESIGNED TO CLIMB” was the title of
an article that Air Trails magazine published
in 1945. It introduced the Zoomer to the FF
modeling community as an evolution of
several FF designs of that era.
As an ardent FFer and designer I wanted
to get the optimum performance from my
models. As an active competitor I studied
the competition and knew that besides
consistent performance I needed a clean,
aerodynamic design that would enable my
aircraft to climb as quickly as possible with
the allowable motor run.
This model design embraced the
minimum wing area allowed for the
engine size that was used, with the
lightest possible weight. I designed the
Zoomer in two sizes: a 60-inch
wingspan for class B and small class C
engines (although several were flown
with .60-size engines) and a 36-inch
wingspan for the smaller .19 class A
engines. Both sizes proved to be successful
and won most of the contests in which they
were entered.
The Zoomer’s fuselage structure was
radical and followed that of my previous
design: the Banshee. It was simple, light,
strong, and easy to assemble and repair
when necessary. It allowed for easy
covering with smooth, flowing lines.
Incorporating a single-wheel landing
gear with two subrudders on the horizontal
stabilizer, the Zoomer allowed quick
takeoffs and smooth landings with
minimum drag. Quick access to the ignition
Leon looks happy with the results of the units and batteries was designed into the
foam Zoomer’s test flights.
11sig2.QXD 9/25/06 2:08 PM Page 3536 MODEL AVIATION
The process for producing the airfoil shape for the wing begins
with making spanwise impressions using a straightedge.
This view shows the creases and the
resulting airfoil shape.
In a similar manner, raise and support the inner wing panel at the
polyhedral joint 13/8 inches, and sand for proper angle.
Measure, raise, and support the tip 15/8 inches above the table
for proper wingtip polyhedral, and then sand the center joint
using 320-grit sandpaper.
Six creases at 1/2-inch intervals complete the wing airfoil. This is a
simple process to learn.
Leon uses a #11 X-Acto blade to cut each wing half for the polyhedral break.
Photos courtesy the author
11sig2.QXD 9/25/06 12:29 PM Page 36November 2006 37
Each wing dihedral angle can be glued with epoxy and secured
with masking tape until the glue cures.
Leon as a World War II pilot with his original Zoomer FF model.
A detailed shot of typical sanding required for the wing dihedral
angles.
Type: Foam RC (converted FF)
Wingspan: 38.5 inches
Wing chord: 7.5 inches
Total wing area: 223 square inches
Dihedral, each tip: 5.625 inches
Overall fuselage length: 25 inches
Stabilizer span: 19 inches
Stabilizer chord (including elevator): 5.75 inches
Stabilizer area: 72 square inches
Motor: AXI brushless 2208/34
Battery requirement: Li-Poly, two-cell, 700-1350 mA
Landing gear: 1/16-inch-diameter wire—single leg (two-wheel option)
Recommended number of channels: Three
Control functions: Rudder, elevator, throttle
Elevator throws: 1/2 inch up, 1/2 inch down
Rudder throw: 3/4 inch left and right
Side thrust: 0°
Downthrust/Upthrust: 0°
Basic materials used in construction: 1/4-inch Dow BlueCor fan-fold foam
Ready-to-fly weight: 9 ounces
Wing loading: 5.77 ounces per square foot
11sig2.QXD 9/25/06 12:39 PM Page 37These airplanes are RC foam replicas of models that Leon designed from 1936 through
1946. All are electric powered! They are similar in construction to the Zoomer.
Left: Famed aviation artist Jim Newman drew this caricature of Leon’s original Zoomer
on a paper napkin during a lunch break between flight sessions.
structure with a simple hatch on the bottom
of the fuselage. The motor was faired into
the fuselage, incorporating a spinner that
smoothed the airflow around the nose of the
aircraft and made for a clean appearance.
A two-blade folding propeller was used
to reduce the frontal drag when the motor
was shut down. The wing and tail used lowdrag
airfoils with simple straight tapered
surfaces that gave a pleasing yet efficient
outline.
To enable such an FF model to have a
steep climbing attitude, most designs used
downthrust, which, although effective,
created extra drag. I built all this into the
design by using a symmetrical airfoil on the
horizontal stabilizer set at a positive angle,
which equaled the necessary downthrust that
would be used.
The wing incidence was also set at a
positive angle so that the wing and stabilizer
would work in unison to equal the usually
needed downthrust. The engine was placed
straight in-line within the nose, giving no
downthrust appearance. The fuselage would
travel at a more normal attitude with the
airflow, thus reducing its drag.
I learned this firsthand when piloting the
full-scale Martin B-26 Marauders. I had
flown most versions of this tremendously
powerful aircraft when the design change
was made to improve its flight
characteristics. Increasing the wingspan by 6
feet and adding slight dihedral made the
airplane easier to fly and enabled it to fly at
a more horizontal attitude. This allowed it to
fly faster with the same power settings.
I also noticed that the B-26’s fuselage
(when observed by flying in formation with
another aircraft) would be more horizontal
than the earlier models with the smaller
wing, instead of looking like it was always
climbing with its nose high. This change in
fuselage attitude (at cruising settings) added
several miles per hour to its flight airspeed.
When translated into a model design, the
same extra efficiency would enable the
Zoomer to climb faster than most models—
and it did!
At one event the Zoomer was calculated
to have climbed 1,500 feet in 30 seconds,
which translates to 3,000 feet per minute—a
hefty performance! The model even
incorporated a small trimmable rudder for
easier flight trim.
The design was popular, and it was
produced in kit form in both sizes. Tens of
thousands were produced and sold.
With the advent of electricity—thanks to
Benjamin Franklin with his kite, Guglielmo
Marconi with his radio, and a great number
of ingenious fellow modelers—we can now
fly these FF designs with an added
advantage of controlling their flight paths
with radio control.
We went several steps further with the
Zoomer and used the latest technology of
Li-Poly batteries, rotary brushless motors
with miniaturized receivers, and servos for
controls. We even used the latest in sheet
foam board technology in this design.
It has been developed to have a high
level of efficiency, low cost, and an easy-toassemble
structure by my good friend Frank
Pisano, who collaborated with me on this
article.
CONSTRUCTION
The construction is simple. We used 1/4-
inch Dow BlueCor fan-fold foam, although
any comparable material can be substituted.
You can find the BlueCor at Lowe’s home
supply or similar stores.
The cost of the foam you actually need is
approximately $2, for less than one of the 24
fan-fold sheets that come in the package. So
please let this encourage you to make this
enjoyable step and build and fly this
Zoomer. You can make more than two
dozen from one package of foam! (If you
have some friends you want to fun-fly with,
make several models at once.)
The plans show the wingspan to be 38.5
inches with a wing area of 223 square
inches. This was scaled down from the
original size so the complete model would
weigh approximately 9 ounces with a twocell,
700-1350 mA Li-Poly battery and a
typical rotary brushless motor: a Hobby
Lobby AXI 2208/34, Hacker A20-22L, or
equivalent.
The wing loading comes out to 5.77
ounces per square foot, making for a
sprightly performing model that will climb
for high altitude yet glide graciously. We
tried several models with different sizes and
weights, and we found this to be optimum.
With a 15-second motor run, this Zoomer
will climb almost out of site.
The Zoomer can be flown at any local
field/park since it is quiet and can make
tight turns to keep it within viewing
distance. This is unlike the other foamies
that hover around endlessly between crashes
and have become almost indistinguishable.
The Zoomer will give you a thrill that
will make your friends envious of its flight
consistency and ease of control. Remember
that this is basically an FF design, and you
will be piloting it around the skies. It will
not get you into trouble; it can fly itself!
We urge you to color the underside of
your model’s wingtips so you can see it
easily when you are flying it in the “wild
blue yonder.” The bright-colored wing
undersurface can save an airplane.
We suggest bright (neon or fluorescent)
orange for excellent visibility. We use
Fluorescent Orange Solartrim trim sheets
since the material is self-adhesive, light, and
easy to apply. Using it only on the bottom of
the wingtips provides enough visibility. And
don’t forget to put your name and telephone
number on your Zoomer—for when you
may let it zoom up and out of sight.
This model has been flown indoors
several times, using low to medium throttle
settings. It is stable and makes graceful
38 MODEL AVIATION
11sig2.QXD 9/25/06 1:10 PM Page 38November 2006 39
See page 183 for Full-Size Plans listing
11sig2.QXD 9/25/06 1:11 PM Page 39turns. This aircraft is not designed to loop or
do rolls; enjoy the thrill of its spectacular
climb and transition into a gentle flat glide,
and then aim it to land right at your feet. The
Zoomer will do it. Try this until you become
proficient enough to enjoy doing it
consistently.
Flights of 15-45 minutes are normal, and
longer flights are possible when there is lift
out there—even off of a treeline at your
park. Be careful with warm air; the Zoomer
really zooms.
This version of the model features a
removable wing held in place with rubber
bands for ease of transportation and damage
resistance. The plans show the full-size
model with notes on its construction.
Basic tools and materials to be used are a
knife; a sandpaper block; cyanoacrylate;
five-minute epoxy; masking tape; 1/32, 1/16,
and 1/8 plywood; a couple strips of 1/16 x 1/4
basswood or hard balsa; and 1/16-inchdiameter
wire for the landing gear. You can
purchase strips of basswood at your local
hobby shop or neighborhood art-and-craft
store.
We show the original single-wheel
landing gear and an optional two-wheel gear.
All the parts are shown on the plans with
necessary fittings and wheel(s).
We even show an optional simple motor
beam mounting feature, which will enable
you to substitute a lower-cost brushed motor
and controller—at a small sacrifice of a
minor weight increase. You can then enjoy
comparable performance at a lower cost.
Start by cutting all parts to shape. Cut
and assemble the landing-gear socket first
using cyanoacrylate. When employing epoxy
to assemble any parts of the Zoomer, apply it
sparingly to minimize weight. Bevel 1/8 inch
from the bottom edges of the horizontal
stabilizer and one side of the vertical fin.
Add basswood stiffeners to each control
surface with a light coat of epoxy. Use clear
packing tape for the hinges, on both sides of
the movable surfaces.
Place stabilizer and elevator surfaces flat
on a bench (with the bevel gap on the
bottom) with a 1/32 inch wire or dowel
between surfaces to create a gap of 1/32 inch.
Press hinge tape in place over both surfaces.
Remove the wire/dowel and then fold
both surfaces in the opposite direction to
apply a second piece of tape to complete the
hinge. Press and rub the tape firmly to secure
it. Use the same process for the vertical
control surfaces before gluing the horizontal
surfaces in place.
Cut the wing panels to size and make the
wing halves, airfoil shape, and dihedral as
shown in the accompanying photos. Crease
the foam wing panels, as shown, in six 1/2-
inch increments to make this novel airfoil.
This process makes an efficient wing with
light weight and tremendous strength. The
photo sequence will walk you through the
wing assembly.
The plans show a new feature that makes
the wing stronger and less prone to minor
scrapes with foliage and/or rough handling.
A short piece of 1/8-inch-inside-diameter
brass (or aluminum) tubing and two skewers
imbedded and epoxied into the LE add
considerable strength and airfoil efficiency
to the Zoomer wing. Four keys locate the
wing position for consistent performance
settings.
You can use masking tape to hold all
parts together while the epoxy sets. Do one
assembly at a time as the epoxy dries. All
incidence and motor-thrust settings are built
in. The photographs show the location of the
motor, controller, battery, servos, etc.
The receiver, motor controller, and
battery are held to the fuselage with Du-Bro
Hook and Loop Mounting Material (product
348). The servos are mounted with Du-Bro
Double Sided Tape (product 634).
We used Du-Bro Micro Control Horns
(product 848) and the Micro Push Rod
System (product 847) to connect to our two
Polk’s Hobby small X-Micro servos. We
used our Polk’s Seeker 6 dual-conversion,
1/2-ounce receiver because of its light
weight, small size, and phenomenal range.
This completes our installation. Servos
should be set to allow 3/4-inch rudder throw
and 1/2-inch elevator throw. Locate
components as shown in the photos. The
balance point, although noncritical, should
be approximately 50% back from the wing
LE.
The original model used the Hobby
Lobby AXI 2208/34 motor and Jeti 8-amp
40 MODELcontroller or Castle Creations Phoenix-10
controller with an APC 10 x 4.7 Slow Flyer
propeller for amazing performance. Several
newer motors have become available since
then and can easily be adapted to the Zoomer
because of the flexibility and simplicity of its
design.
For a lower-cost power package we used
a GWS 350C-C gearing brushed motor and
Castle Creations Pixie-20 controller with the
same APC 10 x 4.7 Slow Flyer propeller. We
built and flew both versions. There isn’t a
great difference in performance between the
two power units, but the brushless package is
sprightlier with slightly less weight.
Bench-test everything before taking the
model out to fly. Make sure the control
surfaces are set properly and that the Zoomer
balances at the suggested position.
This design has an “automatic pilot”
designed into it and will fly by itself, but
avoid severe gusts, which can cause damage
because of the aircraft’s light weight. Upon
launching, the Zoomer will zoom up in a fast
climb and rotate by itself as it spirals upward.
Use gentle control input under power
since the Zoomer really will fly by itself. In a
glide it can make tight turns because of its
inherent stability, and landing at your feet
will be a common happening!
Keep ’em flying! MA
Leon Shulman
Edition: Model Aviation - 2006/11
Page Numbers: 35,36,37,38,39,40,42
Edition: Model Aviation - 2006/11
Page Numbers: 35,36,37,38,39,40,42
November 2006 35
A legendary
modeler’s equally
legendary design
translates into
a peppy RC
electric foam
aircraft
BY LEON SHULMAN
The Zoomer climbs out after making a
flyby for the camera. This model will be
available as an RTF from Polk’s Hobby.
“DESIGNED TO CLIMB” was the title of
an article that Air Trails magazine published
in 1945. It introduced the Zoomer to the FF
modeling community as an evolution of
several FF designs of that era.
As an ardent FFer and designer I wanted
to get the optimum performance from my
models. As an active competitor I studied
the competition and knew that besides
consistent performance I needed a clean,
aerodynamic design that would enable my
aircraft to climb as quickly as possible with
the allowable motor run.
This model design embraced the
minimum wing area allowed for the
engine size that was used, with the
lightest possible weight. I designed the
Zoomer in two sizes: a 60-inch
wingspan for class B and small class C
engines (although several were flown
with .60-size engines) and a 36-inch
wingspan for the smaller .19 class A
engines. Both sizes proved to be successful
and won most of the contests in which they
were entered.
The Zoomer’s fuselage structure was
radical and followed that of my previous
design: the Banshee. It was simple, light,
strong, and easy to assemble and repair
when necessary. It allowed for easy
covering with smooth, flowing lines.
Incorporating a single-wheel landing
gear with two subrudders on the horizontal
stabilizer, the Zoomer allowed quick
takeoffs and smooth landings with
minimum drag. Quick access to the ignition
Leon looks happy with the results of the units and batteries was designed into the
foam Zoomer’s test flights.
11sig2.QXD 9/25/06 2:08 PM Page 3536 MODEL AVIATION
The process for producing the airfoil shape for the wing begins
with making spanwise impressions using a straightedge.
This view shows the creases and the
resulting airfoil shape.
In a similar manner, raise and support the inner wing panel at the
polyhedral joint 13/8 inches, and sand for proper angle.
Measure, raise, and support the tip 15/8 inches above the table
for proper wingtip polyhedral, and then sand the center joint
using 320-grit sandpaper.
Six creases at 1/2-inch intervals complete the wing airfoil. This is a
simple process to learn.
Leon uses a #11 X-Acto blade to cut each wing half for the polyhedral break.
Photos courtesy the author
11sig2.QXD 9/25/06 12:29 PM Page 36November 2006 37
Each wing dihedral angle can be glued with epoxy and secured
with masking tape until the glue cures.
Leon as a World War II pilot with his original Zoomer FF model.
A detailed shot of typical sanding required for the wing dihedral
angles.
Type: Foam RC (converted FF)
Wingspan: 38.5 inches
Wing chord: 7.5 inches
Total wing area: 223 square inches
Dihedral, each tip: 5.625 inches
Overall fuselage length: 25 inches
Stabilizer span: 19 inches
Stabilizer chord (including elevator): 5.75 inches
Stabilizer area: 72 square inches
Motor: AXI brushless 2208/34
Battery requirement: Li-Poly, two-cell, 700-1350 mA
Landing gear: 1/16-inch-diameter wire—single leg (two-wheel option)
Recommended number of channels: Three
Control functions: Rudder, elevator, throttle
Elevator throws: 1/2 inch up, 1/2 inch down
Rudder throw: 3/4 inch left and right
Side thrust: 0°
Downthrust/Upthrust: 0°
Basic materials used in construction: 1/4-inch Dow BlueCor fan-fold foam
Ready-to-fly weight: 9 ounces
Wing loading: 5.77 ounces per square foot
11sig2.QXD 9/25/06 12:39 PM Page 37These airplanes are RC foam replicas of models that Leon designed from 1936 through
1946. All are electric powered! They are similar in construction to the Zoomer.
Left: Famed aviation artist Jim Newman drew this caricature of Leon’s original Zoomer
on a paper napkin during a lunch break between flight sessions.
structure with a simple hatch on the bottom
of the fuselage. The motor was faired into
the fuselage, incorporating a spinner that
smoothed the airflow around the nose of the
aircraft and made for a clean appearance.
A two-blade folding propeller was used
to reduce the frontal drag when the motor
was shut down. The wing and tail used lowdrag
airfoils with simple straight tapered
surfaces that gave a pleasing yet efficient
outline.
To enable such an FF model to have a
steep climbing attitude, most designs used
downthrust, which, although effective,
created extra drag. I built all this into the
design by using a symmetrical airfoil on the
horizontal stabilizer set at a positive angle,
which equaled the necessary downthrust that
would be used.
The wing incidence was also set at a
positive angle so that the wing and stabilizer
would work in unison to equal the usually
needed downthrust. The engine was placed
straight in-line within the nose, giving no
downthrust appearance. The fuselage would
travel at a more normal attitude with the
airflow, thus reducing its drag.
I learned this firsthand when piloting the
full-scale Martin B-26 Marauders. I had
flown most versions of this tremendously
powerful aircraft when the design change
was made to improve its flight
characteristics. Increasing the wingspan by 6
feet and adding slight dihedral made the
airplane easier to fly and enabled it to fly at
a more horizontal attitude. This allowed it to
fly faster with the same power settings.
I also noticed that the B-26’s fuselage
(when observed by flying in formation with
another aircraft) would be more horizontal
than the earlier models with the smaller
wing, instead of looking like it was always
climbing with its nose high. This change in
fuselage attitude (at cruising settings) added
several miles per hour to its flight airspeed.
When translated into a model design, the
same extra efficiency would enable the
Zoomer to climb faster than most models—
and it did!
At one event the Zoomer was calculated
to have climbed 1,500 feet in 30 seconds,
which translates to 3,000 feet per minute—a
hefty performance! The model even
incorporated a small trimmable rudder for
easier flight trim.
The design was popular, and it was
produced in kit form in both sizes. Tens of
thousands were produced and sold.
With the advent of electricity—thanks to
Benjamin Franklin with his kite, Guglielmo
Marconi with his radio, and a great number
of ingenious fellow modelers—we can now
fly these FF designs with an added
advantage of controlling their flight paths
with radio control.
We went several steps further with the
Zoomer and used the latest technology of
Li-Poly batteries, rotary brushless motors
with miniaturized receivers, and servos for
controls. We even used the latest in sheet
foam board technology in this design.
It has been developed to have a high
level of efficiency, low cost, and an easy-toassemble
structure by my good friend Frank
Pisano, who collaborated with me on this
article.
CONSTRUCTION
The construction is simple. We used 1/4-
inch Dow BlueCor fan-fold foam, although
any comparable material can be substituted.
You can find the BlueCor at Lowe’s home
supply or similar stores.
The cost of the foam you actually need is
approximately $2, for less than one of the 24
fan-fold sheets that come in the package. So
please let this encourage you to make this
enjoyable step and build and fly this
Zoomer. You can make more than two
dozen from one package of foam! (If you
have some friends you want to fun-fly with,
make several models at once.)
The plans show the wingspan to be 38.5
inches with a wing area of 223 square
inches. This was scaled down from the
original size so the complete model would
weigh approximately 9 ounces with a twocell,
700-1350 mA Li-Poly battery and a
typical rotary brushless motor: a Hobby
Lobby AXI 2208/34, Hacker A20-22L, or
equivalent.
The wing loading comes out to 5.77
ounces per square foot, making for a
sprightly performing model that will climb
for high altitude yet glide graciously. We
tried several models with different sizes and
weights, and we found this to be optimum.
With a 15-second motor run, this Zoomer
will climb almost out of site.
The Zoomer can be flown at any local
field/park since it is quiet and can make
tight turns to keep it within viewing
distance. This is unlike the other foamies
that hover around endlessly between crashes
and have become almost indistinguishable.
The Zoomer will give you a thrill that
will make your friends envious of its flight
consistency and ease of control. Remember
that this is basically an FF design, and you
will be piloting it around the skies. It will
not get you into trouble; it can fly itself!
We urge you to color the underside of
your model’s wingtips so you can see it
easily when you are flying it in the “wild
blue yonder.” The bright-colored wing
undersurface can save an airplane.
We suggest bright (neon or fluorescent)
orange for excellent visibility. We use
Fluorescent Orange Solartrim trim sheets
since the material is self-adhesive, light, and
easy to apply. Using it only on the bottom of
the wingtips provides enough visibility. And
don’t forget to put your name and telephone
number on your Zoomer—for when you
may let it zoom up and out of sight.
This model has been flown indoors
several times, using low to medium throttle
settings. It is stable and makes graceful
38 MODEL AVIATION
11sig2.QXD 9/25/06 1:10 PM Page 38November 2006 39
See page 183 for Full-Size Plans listing
11sig2.QXD 9/25/06 1:11 PM Page 39turns. This aircraft is not designed to loop or
do rolls; enjoy the thrill of its spectacular
climb and transition into a gentle flat glide,
and then aim it to land right at your feet. The
Zoomer will do it. Try this until you become
proficient enough to enjoy doing it
consistently.
Flights of 15-45 minutes are normal, and
longer flights are possible when there is lift
out there—even off of a treeline at your
park. Be careful with warm air; the Zoomer
really zooms.
This version of the model features a
removable wing held in place with rubber
bands for ease of transportation and damage
resistance. The plans show the full-size
model with notes on its construction.
Basic tools and materials to be used are a
knife; a sandpaper block; cyanoacrylate;
five-minute epoxy; masking tape; 1/32, 1/16,
and 1/8 plywood; a couple strips of 1/16 x 1/4
basswood or hard balsa; and 1/16-inchdiameter
wire for the landing gear. You can
purchase strips of basswood at your local
hobby shop or neighborhood art-and-craft
store.
We show the original single-wheel
landing gear and an optional two-wheel gear.
All the parts are shown on the plans with
necessary fittings and wheel(s).
We even show an optional simple motor
beam mounting feature, which will enable
you to substitute a lower-cost brushed motor
and controller—at a small sacrifice of a
minor weight increase. You can then enjoy
comparable performance at a lower cost.
Start by cutting all parts to shape. Cut
and assemble the landing-gear socket first
using cyanoacrylate. When employing epoxy
to assemble any parts of the Zoomer, apply it
sparingly to minimize weight. Bevel 1/8 inch
from the bottom edges of the horizontal
stabilizer and one side of the vertical fin.
Add basswood stiffeners to each control
surface with a light coat of epoxy. Use clear
packing tape for the hinges, on both sides of
the movable surfaces.
Place stabilizer and elevator surfaces flat
on a bench (with the bevel gap on the
bottom) with a 1/32 inch wire or dowel
between surfaces to create a gap of 1/32 inch.
Press hinge tape in place over both surfaces.
Remove the wire/dowel and then fold
both surfaces in the opposite direction to
apply a second piece of tape to complete the
hinge. Press and rub the tape firmly to secure
it. Use the same process for the vertical
control surfaces before gluing the horizontal
surfaces in place.
Cut the wing panels to size and make the
wing halves, airfoil shape, and dihedral as
shown in the accompanying photos. Crease
the foam wing panels, as shown, in six 1/2-
inch increments to make this novel airfoil.
This process makes an efficient wing with
light weight and tremendous strength. The
photo sequence will walk you through the
wing assembly.
The plans show a new feature that makes
the wing stronger and less prone to minor
scrapes with foliage and/or rough handling.
A short piece of 1/8-inch-inside-diameter
brass (or aluminum) tubing and two skewers
imbedded and epoxied into the LE add
considerable strength and airfoil efficiency
to the Zoomer wing. Four keys locate the
wing position for consistent performance
settings.
You can use masking tape to hold all
parts together while the epoxy sets. Do one
assembly at a time as the epoxy dries. All
incidence and motor-thrust settings are built
in. The photographs show the location of the
motor, controller, battery, servos, etc.
The receiver, motor controller, and
battery are held to the fuselage with Du-Bro
Hook and Loop Mounting Material (product
348). The servos are mounted with Du-Bro
Double Sided Tape (product 634).
We used Du-Bro Micro Control Horns
(product 848) and the Micro Push Rod
System (product 847) to connect to our two
Polk’s Hobby small X-Micro servos. We
used our Polk’s Seeker 6 dual-conversion,
1/2-ounce receiver because of its light
weight, small size, and phenomenal range.
This completes our installation. Servos
should be set to allow 3/4-inch rudder throw
and 1/2-inch elevator throw. Locate
components as shown in the photos. The
balance point, although noncritical, should
be approximately 50% back from the wing
LE.
The original model used the Hobby
Lobby AXI 2208/34 motor and Jeti 8-amp
40 MODELcontroller or Castle Creations Phoenix-10
controller with an APC 10 x 4.7 Slow Flyer
propeller for amazing performance. Several
newer motors have become available since
then and can easily be adapted to the Zoomer
because of the flexibility and simplicity of its
design.
For a lower-cost power package we used
a GWS 350C-C gearing brushed motor and
Castle Creations Pixie-20 controller with the
same APC 10 x 4.7 Slow Flyer propeller. We
built and flew both versions. There isn’t a
great difference in performance between the
two power units, but the brushless package is
sprightlier with slightly less weight.
Bench-test everything before taking the
model out to fly. Make sure the control
surfaces are set properly and that the Zoomer
balances at the suggested position.
This design has an “automatic pilot”
designed into it and will fly by itself, but
avoid severe gusts, which can cause damage
because of the aircraft’s light weight. Upon
launching, the Zoomer will zoom up in a fast
climb and rotate by itself as it spirals upward.
Use gentle control input under power
since the Zoomer really will fly by itself. In a
glide it can make tight turns because of its
inherent stability, and landing at your feet
will be a common happening!
Keep ’em flying! MA
Leon Shulman
Edition: Model Aviation - 2006/11
Page Numbers: 35,36,37,38,39,40,42
November 2006 35
A legendary
modeler’s equally
legendary design
translates into
a peppy RC
electric foam
aircraft
BY LEON SHULMAN
The Zoomer climbs out after making a
flyby for the camera. This model will be
available as an RTF from Polk’s Hobby.
“DESIGNED TO CLIMB” was the title of
an article that Air Trails magazine published
in 1945. It introduced the Zoomer to the FF
modeling community as an evolution of
several FF designs of that era.
As an ardent FFer and designer I wanted
to get the optimum performance from my
models. As an active competitor I studied
the competition and knew that besides
consistent performance I needed a clean,
aerodynamic design that would enable my
aircraft to climb as quickly as possible with
the allowable motor run.
This model design embraced the
minimum wing area allowed for the
engine size that was used, with the
lightest possible weight. I designed the
Zoomer in two sizes: a 60-inch
wingspan for class B and small class C
engines (although several were flown
with .60-size engines) and a 36-inch
wingspan for the smaller .19 class A
engines. Both sizes proved to be successful
and won most of the contests in which they
were entered.
The Zoomer’s fuselage structure was
radical and followed that of my previous
design: the Banshee. It was simple, light,
strong, and easy to assemble and repair
when necessary. It allowed for easy
covering with smooth, flowing lines.
Incorporating a single-wheel landing
gear with two subrudders on the horizontal
stabilizer, the Zoomer allowed quick
takeoffs and smooth landings with
minimum drag. Quick access to the ignition
Leon looks happy with the results of the units and batteries was designed into the
foam Zoomer’s test flights.
11sig2.QXD 9/25/06 2:08 PM Page 3536 MODEL AVIATION
The process for producing the airfoil shape for the wing begins
with making spanwise impressions using a straightedge.
This view shows the creases and the
resulting airfoil shape.
In a similar manner, raise and support the inner wing panel at the
polyhedral joint 13/8 inches, and sand for proper angle.
Measure, raise, and support the tip 15/8 inches above the table
for proper wingtip polyhedral, and then sand the center joint
using 320-grit sandpaper.
Six creases at 1/2-inch intervals complete the wing airfoil. This is a
simple process to learn.
Leon uses a #11 X-Acto blade to cut each wing half for the polyhedral break.
Photos courtesy the author
11sig2.QXD 9/25/06 12:29 PM Page 36November 2006 37
Each wing dihedral angle can be glued with epoxy and secured
with masking tape until the glue cures.
Leon as a World War II pilot with his original Zoomer FF model.
A detailed shot of typical sanding required for the wing dihedral
angles.
Type: Foam RC (converted FF)
Wingspan: 38.5 inches
Wing chord: 7.5 inches
Total wing area: 223 square inches
Dihedral, each tip: 5.625 inches
Overall fuselage length: 25 inches
Stabilizer span: 19 inches
Stabilizer chord (including elevator): 5.75 inches
Stabilizer area: 72 square inches
Motor: AXI brushless 2208/34
Battery requirement: Li-Poly, two-cell, 700-1350 mA
Landing gear: 1/16-inch-diameter wire—single leg (two-wheel option)
Recommended number of channels: Three
Control functions: Rudder, elevator, throttle
Elevator throws: 1/2 inch up, 1/2 inch down
Rudder throw: 3/4 inch left and right
Side thrust: 0°
Downthrust/Upthrust: 0°
Basic materials used in construction: 1/4-inch Dow BlueCor fan-fold foam
Ready-to-fly weight: 9 ounces
Wing loading: 5.77 ounces per square foot
11sig2.QXD 9/25/06 12:39 PM Page 37These airplanes are RC foam replicas of models that Leon designed from 1936 through
1946. All are electric powered! They are similar in construction to the Zoomer.
Left: Famed aviation artist Jim Newman drew this caricature of Leon’s original Zoomer
on a paper napkin during a lunch break between flight sessions.
structure with a simple hatch on the bottom
of the fuselage. The motor was faired into
the fuselage, incorporating a spinner that
smoothed the airflow around the nose of the
aircraft and made for a clean appearance.
A two-blade folding propeller was used
to reduce the frontal drag when the motor
was shut down. The wing and tail used lowdrag
airfoils with simple straight tapered
surfaces that gave a pleasing yet efficient
outline.
To enable such an FF model to have a
steep climbing attitude, most designs used
downthrust, which, although effective,
created extra drag. I built all this into the
design by using a symmetrical airfoil on the
horizontal stabilizer set at a positive angle,
which equaled the necessary downthrust that
would be used.
The wing incidence was also set at a
positive angle so that the wing and stabilizer
would work in unison to equal the usually
needed downthrust. The engine was placed
straight in-line within the nose, giving no
downthrust appearance. The fuselage would
travel at a more normal attitude with the
airflow, thus reducing its drag.
I learned this firsthand when piloting the
full-scale Martin B-26 Marauders. I had
flown most versions of this tremendously
powerful aircraft when the design change
was made to improve its flight
characteristics. Increasing the wingspan by 6
feet and adding slight dihedral made the
airplane easier to fly and enabled it to fly at
a more horizontal attitude. This allowed it to
fly faster with the same power settings.
I also noticed that the B-26’s fuselage
(when observed by flying in formation with
another aircraft) would be more horizontal
than the earlier models with the smaller
wing, instead of looking like it was always
climbing with its nose high. This change in
fuselage attitude (at cruising settings) added
several miles per hour to its flight airspeed.
When translated into a model design, the
same extra efficiency would enable the
Zoomer to climb faster than most models—
and it did!
At one event the Zoomer was calculated
to have climbed 1,500 feet in 30 seconds,
which translates to 3,000 feet per minute—a
hefty performance! The model even
incorporated a small trimmable rudder for
easier flight trim.
The design was popular, and it was
produced in kit form in both sizes. Tens of
thousands were produced and sold.
With the advent of electricity—thanks to
Benjamin Franklin with his kite, Guglielmo
Marconi with his radio, and a great number
of ingenious fellow modelers—we can now
fly these FF designs with an added
advantage of controlling their flight paths
with radio control.
We went several steps further with the
Zoomer and used the latest technology of
Li-Poly batteries, rotary brushless motors
with miniaturized receivers, and servos for
controls. We even used the latest in sheet
foam board technology in this design.
It has been developed to have a high
level of efficiency, low cost, and an easy-toassemble
structure by my good friend Frank
Pisano, who collaborated with me on this
article.
CONSTRUCTION
The construction is simple. We used 1/4-
inch Dow BlueCor fan-fold foam, although
any comparable material can be substituted.
You can find the BlueCor at Lowe’s home
supply or similar stores.
The cost of the foam you actually need is
approximately $2, for less than one of the 24
fan-fold sheets that come in the package. So
please let this encourage you to make this
enjoyable step and build and fly this
Zoomer. You can make more than two
dozen from one package of foam! (If you
have some friends you want to fun-fly with,
make several models at once.)
The plans show the wingspan to be 38.5
inches with a wing area of 223 square
inches. This was scaled down from the
original size so the complete model would
weigh approximately 9 ounces with a twocell,
700-1350 mA Li-Poly battery and a
typical rotary brushless motor: a Hobby
Lobby AXI 2208/34, Hacker A20-22L, or
equivalent.
The wing loading comes out to 5.77
ounces per square foot, making for a
sprightly performing model that will climb
for high altitude yet glide graciously. We
tried several models with different sizes and
weights, and we found this to be optimum.
With a 15-second motor run, this Zoomer
will climb almost out of site.
The Zoomer can be flown at any local
field/park since it is quiet and can make
tight turns to keep it within viewing
distance. This is unlike the other foamies
that hover around endlessly between crashes
and have become almost indistinguishable.
The Zoomer will give you a thrill that
will make your friends envious of its flight
consistency and ease of control. Remember
that this is basically an FF design, and you
will be piloting it around the skies. It will
not get you into trouble; it can fly itself!
We urge you to color the underside of
your model’s wingtips so you can see it
easily when you are flying it in the “wild
blue yonder.” The bright-colored wing
undersurface can save an airplane.
We suggest bright (neon or fluorescent)
orange for excellent visibility. We use
Fluorescent Orange Solartrim trim sheets
since the material is self-adhesive, light, and
easy to apply. Using it only on the bottom of
the wingtips provides enough visibility. And
don’t forget to put your name and telephone
number on your Zoomer—for when you
may let it zoom up and out of sight.
This model has been flown indoors
several times, using low to medium throttle
settings. It is stable and makes graceful
38 MODEL AVIATION
11sig2.QXD 9/25/06 1:10 PM Page 38November 2006 39
See page 183 for Full-Size Plans listing
11sig2.QXD 9/25/06 1:11 PM Page 39turns. This aircraft is not designed to loop or
do rolls; enjoy the thrill of its spectacular
climb and transition into a gentle flat glide,
and then aim it to land right at your feet. The
Zoomer will do it. Try this until you become
proficient enough to enjoy doing it
consistently.
Flights of 15-45 minutes are normal, and
longer flights are possible when there is lift
out there—even off of a treeline at your
park. Be careful with warm air; the Zoomer
really zooms.
This version of the model features a
removable wing held in place with rubber
bands for ease of transportation and damage
resistance. The plans show the full-size
model with notes on its construction.
Basic tools and materials to be used are a
knife; a sandpaper block; cyanoacrylate;
five-minute epoxy; masking tape; 1/32, 1/16,
and 1/8 plywood; a couple strips of 1/16 x 1/4
basswood or hard balsa; and 1/16-inchdiameter
wire for the landing gear. You can
purchase strips of basswood at your local
hobby shop or neighborhood art-and-craft
store.
We show the original single-wheel
landing gear and an optional two-wheel gear.
All the parts are shown on the plans with
necessary fittings and wheel(s).
We even show an optional simple motor
beam mounting feature, which will enable
you to substitute a lower-cost brushed motor
and controller—at a small sacrifice of a
minor weight increase. You can then enjoy
comparable performance at a lower cost.
Start by cutting all parts to shape. Cut
and assemble the landing-gear socket first
using cyanoacrylate. When employing epoxy
to assemble any parts of the Zoomer, apply it
sparingly to minimize weight. Bevel 1/8 inch
from the bottom edges of the horizontal
stabilizer and one side of the vertical fin.
Add basswood stiffeners to each control
surface with a light coat of epoxy. Use clear
packing tape for the hinges, on both sides of
the movable surfaces.
Place stabilizer and elevator surfaces flat
on a bench (with the bevel gap on the
bottom) with a 1/32 inch wire or dowel
between surfaces to create a gap of 1/32 inch.
Press hinge tape in place over both surfaces.
Remove the wire/dowel and then fold
both surfaces in the opposite direction to
apply a second piece of tape to complete the
hinge. Press and rub the tape firmly to secure
it. Use the same process for the vertical
control surfaces before gluing the horizontal
surfaces in place.
Cut the wing panels to size and make the
wing halves, airfoil shape, and dihedral as
shown in the accompanying photos. Crease
the foam wing panels, as shown, in six 1/2-
inch increments to make this novel airfoil.
This process makes an efficient wing with
light weight and tremendous strength. The
photo sequence will walk you through the
wing assembly.
The plans show a new feature that makes
the wing stronger and less prone to minor
scrapes with foliage and/or rough handling.
A short piece of 1/8-inch-inside-diameter
brass (or aluminum) tubing and two skewers
imbedded and epoxied into the LE add
considerable strength and airfoil efficiency
to the Zoomer wing. Four keys locate the
wing position for consistent performance
settings.
You can use masking tape to hold all
parts together while the epoxy sets. Do one
assembly at a time as the epoxy dries. All
incidence and motor-thrust settings are built
in. The photographs show the location of the
motor, controller, battery, servos, etc.
The receiver, motor controller, and
battery are held to the fuselage with Du-Bro
Hook and Loop Mounting Material (product
348). The servos are mounted with Du-Bro
Double Sided Tape (product 634).
We used Du-Bro Micro Control Horns
(product 848) and the Micro Push Rod
System (product 847) to connect to our two
Polk’s Hobby small X-Micro servos. We
used our Polk’s Seeker 6 dual-conversion,
1/2-ounce receiver because of its light
weight, small size, and phenomenal range.
This completes our installation. Servos
should be set to allow 3/4-inch rudder throw
and 1/2-inch elevator throw. Locate
components as shown in the photos. The
balance point, although noncritical, should
be approximately 50% back from the wing
LE.
The original model used the Hobby
Lobby AXI 2208/34 motor and Jeti 8-amp
40 MODELcontroller or Castle Creations Phoenix-10
controller with an APC 10 x 4.7 Slow Flyer
propeller for amazing performance. Several
newer motors have become available since
then and can easily be adapted to the Zoomer
because of the flexibility and simplicity of its
design.
For a lower-cost power package we used
a GWS 350C-C gearing brushed motor and
Castle Creations Pixie-20 controller with the
same APC 10 x 4.7 Slow Flyer propeller. We
built and flew both versions. There isn’t a
great difference in performance between the
two power units, but the brushless package is
sprightlier with slightly less weight.
Bench-test everything before taking the
model out to fly. Make sure the control
surfaces are set properly and that the Zoomer
balances at the suggested position.
This design has an “automatic pilot”
designed into it and will fly by itself, but
avoid severe gusts, which can cause damage
because of the aircraft’s light weight. Upon
launching, the Zoomer will zoom up in a fast
climb and rotate by itself as it spirals upward.
Use gentle control input under power
since the Zoomer really will fly by itself. In a
glide it can make tight turns because of its
inherent stability, and landing at your feet
will be a common happening!
Keep ’em flying! MA
Leon Shulman
Edition: Model Aviation - 2006/11
Page Numbers: 35,36,37,38,39,40,42
November 2006 35
A legendary
modeler’s equally
legendary design
translates into
a peppy RC
electric foam
aircraft
BY LEON SHULMAN
The Zoomer climbs out after making a
flyby for the camera. This model will be
available as an RTF from Polk’s Hobby.
“DESIGNED TO CLIMB” was the title of
an article that Air Trails magazine published
in 1945. It introduced the Zoomer to the FF
modeling community as an evolution of
several FF designs of that era.
As an ardent FFer and designer I wanted
to get the optimum performance from my
models. As an active competitor I studied
the competition and knew that besides
consistent performance I needed a clean,
aerodynamic design that would enable my
aircraft to climb as quickly as possible with
the allowable motor run.
This model design embraced the
minimum wing area allowed for the
engine size that was used, with the
lightest possible weight. I designed the
Zoomer in two sizes: a 60-inch
wingspan for class B and small class C
engines (although several were flown
with .60-size engines) and a 36-inch
wingspan for the smaller .19 class A
engines. Both sizes proved to be successful
and won most of the contests in which they
were entered.
The Zoomer’s fuselage structure was
radical and followed that of my previous
design: the Banshee. It was simple, light,
strong, and easy to assemble and repair
when necessary. It allowed for easy
covering with smooth, flowing lines.
Incorporating a single-wheel landing
gear with two subrudders on the horizontal
stabilizer, the Zoomer allowed quick
takeoffs and smooth landings with
minimum drag. Quick access to the ignition
Leon looks happy with the results of the units and batteries was designed into the
foam Zoomer’s test flights.
11sig2.QXD 9/25/06 2:08 PM Page 3536 MODEL AVIATION
The process for producing the airfoil shape for the wing begins
with making spanwise impressions using a straightedge.
This view shows the creases and the
resulting airfoil shape.
In a similar manner, raise and support the inner wing panel at the
polyhedral joint 13/8 inches, and sand for proper angle.
Measure, raise, and support the tip 15/8 inches above the table
for proper wingtip polyhedral, and then sand the center joint
using 320-grit sandpaper.
Six creases at 1/2-inch intervals complete the wing airfoil. This is a
simple process to learn.
Leon uses a #11 X-Acto blade to cut each wing half for the polyhedral break.
Photos courtesy the author
11sig2.QXD 9/25/06 12:29 PM Page 36November 2006 37
Each wing dihedral angle can be glued with epoxy and secured
with masking tape until the glue cures.
Leon as a World War II pilot with his original Zoomer FF model.
A detailed shot of typical sanding required for the wing dihedral
angles.
Type: Foam RC (converted FF)
Wingspan: 38.5 inches
Wing chord: 7.5 inches
Total wing area: 223 square inches
Dihedral, each tip: 5.625 inches
Overall fuselage length: 25 inches
Stabilizer span: 19 inches
Stabilizer chord (including elevator): 5.75 inches
Stabilizer area: 72 square inches
Motor: AXI brushless 2208/34
Battery requirement: Li-Poly, two-cell, 700-1350 mA
Landing gear: 1/16-inch-diameter wire—single leg (two-wheel option)
Recommended number of channels: Three
Control functions: Rudder, elevator, throttle
Elevator throws: 1/2 inch up, 1/2 inch down
Rudder throw: 3/4 inch left and right
Side thrust: 0°
Downthrust/Upthrust: 0°
Basic materials used in construction: 1/4-inch Dow BlueCor fan-fold foam
Ready-to-fly weight: 9 ounces
Wing loading: 5.77 ounces per square foot
11sig2.QXD 9/25/06 12:39 PM Page 37These airplanes are RC foam replicas of models that Leon designed from 1936 through
1946. All are electric powered! They are similar in construction to the Zoomer.
Left: Famed aviation artist Jim Newman drew this caricature of Leon’s original Zoomer
on a paper napkin during a lunch break between flight sessions.
structure with a simple hatch on the bottom
of the fuselage. The motor was faired into
the fuselage, incorporating a spinner that
smoothed the airflow around the nose of the
aircraft and made for a clean appearance.
A two-blade folding propeller was used
to reduce the frontal drag when the motor
was shut down. The wing and tail used lowdrag
airfoils with simple straight tapered
surfaces that gave a pleasing yet efficient
outline.
To enable such an FF model to have a
steep climbing attitude, most designs used
downthrust, which, although effective,
created extra drag. I built all this into the
design by using a symmetrical airfoil on the
horizontal stabilizer set at a positive angle,
which equaled the necessary downthrust that
would be used.
The wing incidence was also set at a
positive angle so that the wing and stabilizer
would work in unison to equal the usually
needed downthrust. The engine was placed
straight in-line within the nose, giving no
downthrust appearance. The fuselage would
travel at a more normal attitude with the
airflow, thus reducing its drag.
I learned this firsthand when piloting the
full-scale Martin B-26 Marauders. I had
flown most versions of this tremendously
powerful aircraft when the design change
was made to improve its flight
characteristics. Increasing the wingspan by 6
feet and adding slight dihedral made the
airplane easier to fly and enabled it to fly at
a more horizontal attitude. This allowed it to
fly faster with the same power settings.
I also noticed that the B-26’s fuselage
(when observed by flying in formation with
another aircraft) would be more horizontal
than the earlier models with the smaller
wing, instead of looking like it was always
climbing with its nose high. This change in
fuselage attitude (at cruising settings) added
several miles per hour to its flight airspeed.
When translated into a model design, the
same extra efficiency would enable the
Zoomer to climb faster than most models—
and it did!
At one event the Zoomer was calculated
to have climbed 1,500 feet in 30 seconds,
which translates to 3,000 feet per minute—a
hefty performance! The model even
incorporated a small trimmable rudder for
easier flight trim.
The design was popular, and it was
produced in kit form in both sizes. Tens of
thousands were produced and sold.
With the advent of electricity—thanks to
Benjamin Franklin with his kite, Guglielmo
Marconi with his radio, and a great number
of ingenious fellow modelers—we can now
fly these FF designs with an added
advantage of controlling their flight paths
with radio control.
We went several steps further with the
Zoomer and used the latest technology of
Li-Poly batteries, rotary brushless motors
with miniaturized receivers, and servos for
controls. We even used the latest in sheet
foam board technology in this design.
It has been developed to have a high
level of efficiency, low cost, and an easy-toassemble
structure by my good friend Frank
Pisano, who collaborated with me on this
article.
CONSTRUCTION
The construction is simple. We used 1/4-
inch Dow BlueCor fan-fold foam, although
any comparable material can be substituted.
You can find the BlueCor at Lowe’s home
supply or similar stores.
The cost of the foam you actually need is
approximately $2, for less than one of the 24
fan-fold sheets that come in the package. So
please let this encourage you to make this
enjoyable step and build and fly this
Zoomer. You can make more than two
dozen from one package of foam! (If you
have some friends you want to fun-fly with,
make several models at once.)
The plans show the wingspan to be 38.5
inches with a wing area of 223 square
inches. This was scaled down from the
original size so the complete model would
weigh approximately 9 ounces with a twocell,
700-1350 mA Li-Poly battery and a
typical rotary brushless motor: a Hobby
Lobby AXI 2208/34, Hacker A20-22L, or
equivalent.
The wing loading comes out to 5.77
ounces per square foot, making for a
sprightly performing model that will climb
for high altitude yet glide graciously. We
tried several models with different sizes and
weights, and we found this to be optimum.
With a 15-second motor run, this Zoomer
will climb almost out of site.
The Zoomer can be flown at any local
field/park since it is quiet and can make
tight turns to keep it within viewing
distance. This is unlike the other foamies
that hover around endlessly between crashes
and have become almost indistinguishable.
The Zoomer will give you a thrill that
will make your friends envious of its flight
consistency and ease of control. Remember
that this is basically an FF design, and you
will be piloting it around the skies. It will
not get you into trouble; it can fly itself!
We urge you to color the underside of
your model’s wingtips so you can see it
easily when you are flying it in the “wild
blue yonder.” The bright-colored wing
undersurface can save an airplane.
We suggest bright (neon or fluorescent)
orange for excellent visibility. We use
Fluorescent Orange Solartrim trim sheets
since the material is self-adhesive, light, and
easy to apply. Using it only on the bottom of
the wingtips provides enough visibility. And
don’t forget to put your name and telephone
number on your Zoomer—for when you
may let it zoom up and out of sight.
This model has been flown indoors
several times, using low to medium throttle
settings. It is stable and makes graceful
38 MODEL AVIATION
11sig2.QXD 9/25/06 1:10 PM Page 38November 2006 39
See page 183 for Full-Size Plans listing
11sig2.QXD 9/25/06 1:11 PM Page 39turns. This aircraft is not designed to loop or
do rolls; enjoy the thrill of its spectacular
climb and transition into a gentle flat glide,
and then aim it to land right at your feet. The
Zoomer will do it. Try this until you become
proficient enough to enjoy doing it
consistently.
Flights of 15-45 minutes are normal, and
longer flights are possible when there is lift
out there—even off of a treeline at your
park. Be careful with warm air; the Zoomer
really zooms.
This version of the model features a
removable wing held in place with rubber
bands for ease of transportation and damage
resistance. The plans show the full-size
model with notes on its construction.
Basic tools and materials to be used are a
knife; a sandpaper block; cyanoacrylate;
five-minute epoxy; masking tape; 1/32, 1/16,
and 1/8 plywood; a couple strips of 1/16 x 1/4
basswood or hard balsa; and 1/16-inchdiameter
wire for the landing gear. You can
purchase strips of basswood at your local
hobby shop or neighborhood art-and-craft
store.
We show the original single-wheel
landing gear and an optional two-wheel gear.
All the parts are shown on the plans with
necessary fittings and wheel(s).
We even show an optional simple motor
beam mounting feature, which will enable
you to substitute a lower-cost brushed motor
and controller—at a small sacrifice of a
minor weight increase. You can then enjoy
comparable performance at a lower cost.
Start by cutting all parts to shape. Cut
and assemble the landing-gear socket first
using cyanoacrylate. When employing epoxy
to assemble any parts of the Zoomer, apply it
sparingly to minimize weight. Bevel 1/8 inch
from the bottom edges of the horizontal
stabilizer and one side of the vertical fin.
Add basswood stiffeners to each control
surface with a light coat of epoxy. Use clear
packing tape for the hinges, on both sides of
the movable surfaces.
Place stabilizer and elevator surfaces flat
on a bench (with the bevel gap on the
bottom) with a 1/32 inch wire or dowel
between surfaces to create a gap of 1/32 inch.
Press hinge tape in place over both surfaces.
Remove the wire/dowel and then fold
both surfaces in the opposite direction to
apply a second piece of tape to complete the
hinge. Press and rub the tape firmly to secure
it. Use the same process for the vertical
control surfaces before gluing the horizontal
surfaces in place.
Cut the wing panels to size and make the
wing halves, airfoil shape, and dihedral as
shown in the accompanying photos. Crease
the foam wing panels, as shown, in six 1/2-
inch increments to make this novel airfoil.
This process makes an efficient wing with
light weight and tremendous strength. The
photo sequence will walk you through the
wing assembly.
The plans show a new feature that makes
the wing stronger and less prone to minor
scrapes with foliage and/or rough handling.
A short piece of 1/8-inch-inside-diameter
brass (or aluminum) tubing and two skewers
imbedded and epoxied into the LE add
considerable strength and airfoil efficiency
to the Zoomer wing. Four keys locate the
wing position for consistent performance
settings.
You can use masking tape to hold all
parts together while the epoxy sets. Do one
assembly at a time as the epoxy dries. All
incidence and motor-thrust settings are built
in. The photographs show the location of the
motor, controller, battery, servos, etc.
The receiver, motor controller, and
battery are held to the fuselage with Du-Bro
Hook and Loop Mounting Material (product
348). The servos are mounted with Du-Bro
Double Sided Tape (product 634).
We used Du-Bro Micro Control Horns
(product 848) and the Micro Push Rod
System (product 847) to connect to our two
Polk’s Hobby small X-Micro servos. We
used our Polk’s Seeker 6 dual-conversion,
1/2-ounce receiver because of its light
weight, small size, and phenomenal range.
This completes our installation. Servos
should be set to allow 3/4-inch rudder throw
and 1/2-inch elevator throw. Locate
components as shown in the photos. The
balance point, although noncritical, should
be approximately 50% back from the wing
LE.
The original model used the Hobby
Lobby AXI 2208/34 motor and Jeti 8-amp
40 MODELcontroller or Castle Creations Phoenix-10
controller with an APC 10 x 4.7 Slow Flyer
propeller for amazing performance. Several
newer motors have become available since
then and can easily be adapted to the Zoomer
because of the flexibility and simplicity of its
design.
For a lower-cost power package we used
a GWS 350C-C gearing brushed motor and
Castle Creations Pixie-20 controller with the
same APC 10 x 4.7 Slow Flyer propeller. We
built and flew both versions. There isn’t a
great difference in performance between the
two power units, but the brushless package is
sprightlier with slightly less weight.
Bench-test everything before taking the
model out to fly. Make sure the control
surfaces are set properly and that the Zoomer
balances at the suggested position.
This design has an “automatic pilot”
designed into it and will fly by itself, but
avoid severe gusts, which can cause damage
because of the aircraft’s light weight. Upon
launching, the Zoomer will zoom up in a fast
climb and rotate by itself as it spirals upward.
Use gentle control input under power
since the Zoomer really will fly by itself. In a
glide it can make tight turns because of its
inherent stability, and landing at your feet
will be a common happening!
Keep ’em flying! MA
Leon Shulman
Edition: Model Aviation - 2006/11
Page Numbers: 35,36,37,38,39,40,42
November 2006 35
A legendary
modeler’s equally
legendary design
translates into
a peppy RC
electric foam
aircraft
BY LEON SHULMAN
The Zoomer climbs out after making a
flyby for the camera. This model will be
available as an RTF from Polk’s Hobby.
“DESIGNED TO CLIMB” was the title of
an article that Air Trails magazine published
in 1945. It introduced the Zoomer to the FF
modeling community as an evolution of
several FF designs of that era.
As an ardent FFer and designer I wanted
to get the optimum performance from my
models. As an active competitor I studied
the competition and knew that besides
consistent performance I needed a clean,
aerodynamic design that would enable my
aircraft to climb as quickly as possible with
the allowable motor run.
This model design embraced the
minimum wing area allowed for the
engine size that was used, with the
lightest possible weight. I designed the
Zoomer in two sizes: a 60-inch
wingspan for class B and small class C
engines (although several were flown
with .60-size engines) and a 36-inch
wingspan for the smaller .19 class A
engines. Both sizes proved to be successful
and won most of the contests in which they
were entered.
The Zoomer’s fuselage structure was
radical and followed that of my previous
design: the Banshee. It was simple, light,
strong, and easy to assemble and repair
when necessary. It allowed for easy
covering with smooth, flowing lines.
Incorporating a single-wheel landing
gear with two subrudders on the horizontal
stabilizer, the Zoomer allowed quick
takeoffs and smooth landings with
minimum drag. Quick access to the ignition
Leon looks happy with the results of the units and batteries was designed into the
foam Zoomer’s test flights.
11sig2.QXD 9/25/06 2:08 PM Page 3536 MODEL AVIATION
The process for producing the airfoil shape for the wing begins
with making spanwise impressions using a straightedge.
This view shows the creases and the
resulting airfoil shape.
In a similar manner, raise and support the inner wing panel at the
polyhedral joint 13/8 inches, and sand for proper angle.
Measure, raise, and support the tip 15/8 inches above the table
for proper wingtip polyhedral, and then sand the center joint
using 320-grit sandpaper.
Six creases at 1/2-inch intervals complete the wing airfoil. This is a
simple process to learn.
Leon uses a #11 X-Acto blade to cut each wing half for the polyhedral break.
Photos courtesy the author
11sig2.QXD 9/25/06 12:29 PM Page 36November 2006 37
Each wing dihedral angle can be glued with epoxy and secured
with masking tape until the glue cures.
Leon as a World War II pilot with his original Zoomer FF model.
A detailed shot of typical sanding required for the wing dihedral
angles.
Type: Foam RC (converted FF)
Wingspan: 38.5 inches
Wing chord: 7.5 inches
Total wing area: 223 square inches
Dihedral, each tip: 5.625 inches
Overall fuselage length: 25 inches
Stabilizer span: 19 inches
Stabilizer chord (including elevator): 5.75 inches
Stabilizer area: 72 square inches
Motor: AXI brushless 2208/34
Battery requirement: Li-Poly, two-cell, 700-1350 mA
Landing gear: 1/16-inch-diameter wire—single leg (two-wheel option)
Recommended number of channels: Three
Control functions: Rudder, elevator, throttle
Elevator throws: 1/2 inch up, 1/2 inch down
Rudder throw: 3/4 inch left and right
Side thrust: 0°
Downthrust/Upthrust: 0°
Basic materials used in construction: 1/4-inch Dow BlueCor fan-fold foam
Ready-to-fly weight: 9 ounces
Wing loading: 5.77 ounces per square foot
11sig2.QXD 9/25/06 12:39 PM Page 37These airplanes are RC foam replicas of models that Leon designed from 1936 through
1946. All are electric powered! They are similar in construction to the Zoomer.
Left: Famed aviation artist Jim Newman drew this caricature of Leon’s original Zoomer
on a paper napkin during a lunch break between flight sessions.
structure with a simple hatch on the bottom
of the fuselage. The motor was faired into
the fuselage, incorporating a spinner that
smoothed the airflow around the nose of the
aircraft and made for a clean appearance.
A two-blade folding propeller was used
to reduce the frontal drag when the motor
was shut down. The wing and tail used lowdrag
airfoils with simple straight tapered
surfaces that gave a pleasing yet efficient
outline.
To enable such an FF model to have a
steep climbing attitude, most designs used
downthrust, which, although effective,
created extra drag. I built all this into the
design by using a symmetrical airfoil on the
horizontal stabilizer set at a positive angle,
which equaled the necessary downthrust that
would be used.
The wing incidence was also set at a
positive angle so that the wing and stabilizer
would work in unison to equal the usually
needed downthrust. The engine was placed
straight in-line within the nose, giving no
downthrust appearance. The fuselage would
travel at a more normal attitude with the
airflow, thus reducing its drag.
I learned this firsthand when piloting the
full-scale Martin B-26 Marauders. I had
flown most versions of this tremendously
powerful aircraft when the design change
was made to improve its flight
characteristics. Increasing the wingspan by 6
feet and adding slight dihedral made the
airplane easier to fly and enabled it to fly at
a more horizontal attitude. This allowed it to
fly faster with the same power settings.
I also noticed that the B-26’s fuselage
(when observed by flying in formation with
another aircraft) would be more horizontal
than the earlier models with the smaller
wing, instead of looking like it was always
climbing with its nose high. This change in
fuselage attitude (at cruising settings) added
several miles per hour to its flight airspeed.
When translated into a model design, the
same extra efficiency would enable the
Zoomer to climb faster than most models—
and it did!
At one event the Zoomer was calculated
to have climbed 1,500 feet in 30 seconds,
which translates to 3,000 feet per minute—a
hefty performance! The model even
incorporated a small trimmable rudder for
easier flight trim.
The design was popular, and it was
produced in kit form in both sizes. Tens of
thousands were produced and sold.
With the advent of electricity—thanks to
Benjamin Franklin with his kite, Guglielmo
Marconi with his radio, and a great number
of ingenious fellow modelers—we can now
fly these FF designs with an added
advantage of controlling their flight paths
with radio control.
We went several steps further with the
Zoomer and used the latest technology of
Li-Poly batteries, rotary brushless motors
with miniaturized receivers, and servos for
controls. We even used the latest in sheet
foam board technology in this design.
It has been developed to have a high
level of efficiency, low cost, and an easy-toassemble
structure by my good friend Frank
Pisano, who collaborated with me on this
article.
CONSTRUCTION
The construction is simple. We used 1/4-
inch Dow BlueCor fan-fold foam, although
any comparable material can be substituted.
You can find the BlueCor at Lowe’s home
supply or similar stores.
The cost of the foam you actually need is
approximately $2, for less than one of the 24
fan-fold sheets that come in the package. So
please let this encourage you to make this
enjoyable step and build and fly this
Zoomer. You can make more than two
dozen from one package of foam! (If you
have some friends you want to fun-fly with,
make several models at once.)
The plans show the wingspan to be 38.5
inches with a wing area of 223 square
inches. This was scaled down from the
original size so the complete model would
weigh approximately 9 ounces with a twocell,
700-1350 mA Li-Poly battery and a
typical rotary brushless motor: a Hobby
Lobby AXI 2208/34, Hacker A20-22L, or
equivalent.
The wing loading comes out to 5.77
ounces per square foot, making for a
sprightly performing model that will climb
for high altitude yet glide graciously. We
tried several models with different sizes and
weights, and we found this to be optimum.
With a 15-second motor run, this Zoomer
will climb almost out of site.
The Zoomer can be flown at any local
field/park since it is quiet and can make
tight turns to keep it within viewing
distance. This is unlike the other foamies
that hover around endlessly between crashes
and have become almost indistinguishable.
The Zoomer will give you a thrill that
will make your friends envious of its flight
consistency and ease of control. Remember
that this is basically an FF design, and you
will be piloting it around the skies. It will
not get you into trouble; it can fly itself!
We urge you to color the underside of
your model’s wingtips so you can see it
easily when you are flying it in the “wild
blue yonder.” The bright-colored wing
undersurface can save an airplane.
We suggest bright (neon or fluorescent)
orange for excellent visibility. We use
Fluorescent Orange Solartrim trim sheets
since the material is self-adhesive, light, and
easy to apply. Using it only on the bottom of
the wingtips provides enough visibility. And
don’t forget to put your name and telephone
number on your Zoomer—for when you
may let it zoom up and out of sight.
This model has been flown indoors
several times, using low to medium throttle
settings. It is stable and makes graceful
38 MODEL AVIATION
11sig2.QXD 9/25/06 1:10 PM Page 38November 2006 39
See page 183 for Full-Size Plans listing
11sig2.QXD 9/25/06 1:11 PM Page 39turns. This aircraft is not designed to loop or
do rolls; enjoy the thrill of its spectacular
climb and transition into a gentle flat glide,
and then aim it to land right at your feet. The
Zoomer will do it. Try this until you become
proficient enough to enjoy doing it
consistently.
Flights of 15-45 minutes are normal, and
longer flights are possible when there is lift
out there—even off of a treeline at your
park. Be careful with warm air; the Zoomer
really zooms.
This version of the model features a
removable wing held in place with rubber
bands for ease of transportation and damage
resistance. The plans show the full-size
model with notes on its construction.
Basic tools and materials to be used are a
knife; a sandpaper block; cyanoacrylate;
five-minute epoxy; masking tape; 1/32, 1/16,
and 1/8 plywood; a couple strips of 1/16 x 1/4
basswood or hard balsa; and 1/16-inchdiameter
wire for the landing gear. You can
purchase strips of basswood at your local
hobby shop or neighborhood art-and-craft
store.
We show the original single-wheel
landing gear and an optional two-wheel gear.
All the parts are shown on the plans with
necessary fittings and wheel(s).
We even show an optional simple motor
beam mounting feature, which will enable
you to substitute a lower-cost brushed motor
and controller—at a small sacrifice of a
minor weight increase. You can then enjoy
comparable performance at a lower cost.
Start by cutting all parts to shape. Cut
and assemble the landing-gear socket first
using cyanoacrylate. When employing epoxy
to assemble any parts of the Zoomer, apply it
sparingly to minimize weight. Bevel 1/8 inch
from the bottom edges of the horizontal
stabilizer and one side of the vertical fin.
Add basswood stiffeners to each control
surface with a light coat of epoxy. Use clear
packing tape for the hinges, on both sides of
the movable surfaces.
Place stabilizer and elevator surfaces flat
on a bench (with the bevel gap on the
bottom) with a 1/32 inch wire or dowel
between surfaces to create a gap of 1/32 inch.
Press hinge tape in place over both surfaces.
Remove the wire/dowel and then fold
both surfaces in the opposite direction to
apply a second piece of tape to complete the
hinge. Press and rub the tape firmly to secure
it. Use the same process for the vertical
control surfaces before gluing the horizontal
surfaces in place.
Cut the wing panels to size and make the
wing halves, airfoil shape, and dihedral as
shown in the accompanying photos. Crease
the foam wing panels, as shown, in six 1/2-
inch increments to make this novel airfoil.
This process makes an efficient wing with
light weight and tremendous strength. The
photo sequence will walk you through the
wing assembly.
The plans show a new feature that makes
the wing stronger and less prone to minor
scrapes with foliage and/or rough handling.
A short piece of 1/8-inch-inside-diameter
brass (or aluminum) tubing and two skewers
imbedded and epoxied into the LE add
considerable strength and airfoil efficiency
to the Zoomer wing. Four keys locate the
wing position for consistent performance
settings.
You can use masking tape to hold all
parts together while the epoxy sets. Do one
assembly at a time as the epoxy dries. All
incidence and motor-thrust settings are built
in. The photographs show the location of the
motor, controller, battery, servos, etc.
The receiver, motor controller, and
battery are held to the fuselage with Du-Bro
Hook and Loop Mounting Material (product
348). The servos are mounted with Du-Bro
Double Sided Tape (product 634).
We used Du-Bro Micro Control Horns
(product 848) and the Micro Push Rod
System (product 847) to connect to our two
Polk’s Hobby small X-Micro servos. We
used our Polk’s Seeker 6 dual-conversion,
1/2-ounce receiver because of its light
weight, small size, and phenomenal range.
This completes our installation. Servos
should be set to allow 3/4-inch rudder throw
and 1/2-inch elevator throw. Locate
components as shown in the photos. The
balance point, although noncritical, should
be approximately 50% back from the wing
LE.
The original model used the Hobby
Lobby AXI 2208/34 motor and Jeti 8-amp
40 MODELcontroller or Castle Creations Phoenix-10
controller with an APC 10 x 4.7 Slow Flyer
propeller for amazing performance. Several
newer motors have become available since
then and can easily be adapted to the Zoomer
because of the flexibility and simplicity of its
design.
For a lower-cost power package we used
a GWS 350C-C gearing brushed motor and
Castle Creations Pixie-20 controller with the
same APC 10 x 4.7 Slow Flyer propeller. We
built and flew both versions. There isn’t a
great difference in performance between the
two power units, but the brushless package is
sprightlier with slightly less weight.
Bench-test everything before taking the
model out to fly. Make sure the control
surfaces are set properly and that the Zoomer
balances at the suggested position.
This design has an “automatic pilot”
designed into it and will fly by itself, but
avoid severe gusts, which can cause damage
because of the aircraft’s light weight. Upon
launching, the Zoomer will zoom up in a fast
climb and rotate by itself as it spirals upward.
Use gentle control input under power
since the Zoomer really will fly by itself. In a
glide it can make tight turns because of its
inherent stability, and landing at your feet
will be a common happening!
Keep ’em flying! MA
Leon Shulman
Edition: Model Aviation - 2006/11
Page Numbers: 35,36,37,38,39,40,42
November 2006 35
A legendary
modeler’s equally
legendary design
translates into
a peppy RC
electric foam
aircraft
BY LEON SHULMAN
The Zoomer climbs out after making a
flyby for the camera. This model will be
available as an RTF from Polk’s Hobby.
“DESIGNED TO CLIMB” was the title of
an article that Air Trails magazine published
in 1945. It introduced the Zoomer to the FF
modeling community as an evolution of
several FF designs of that era.
As an ardent FFer and designer I wanted
to get the optimum performance from my
models. As an active competitor I studied
the competition and knew that besides
consistent performance I needed a clean,
aerodynamic design that would enable my
aircraft to climb as quickly as possible with
the allowable motor run.
This model design embraced the
minimum wing area allowed for the
engine size that was used, with the
lightest possible weight. I designed the
Zoomer in two sizes: a 60-inch
wingspan for class B and small class C
engines (although several were flown
with .60-size engines) and a 36-inch
wingspan for the smaller .19 class A
engines. Both sizes proved to be successful
and won most of the contests in which they
were entered.
The Zoomer’s fuselage structure was
radical and followed that of my previous
design: the Banshee. It was simple, light,
strong, and easy to assemble and repair
when necessary. It allowed for easy
covering with smooth, flowing lines.
Incorporating a single-wheel landing
gear with two subrudders on the horizontal
stabilizer, the Zoomer allowed quick
takeoffs and smooth landings with
minimum drag. Quick access to the ignition
Leon looks happy with the results of the units and batteries was designed into the
foam Zoomer’s test flights.
11sig2.QXD 9/25/06 2:08 PM Page 3536 MODEL AVIATION
The process for producing the airfoil shape for the wing begins
with making spanwise impressions using a straightedge.
This view shows the creases and the
resulting airfoil shape.
In a similar manner, raise and support the inner wing panel at the
polyhedral joint 13/8 inches, and sand for proper angle.
Measure, raise, and support the tip 15/8 inches above the table
for proper wingtip polyhedral, and then sand the center joint
using 320-grit sandpaper.
Six creases at 1/2-inch intervals complete the wing airfoil. This is a
simple process to learn.
Leon uses a #11 X-Acto blade to cut each wing half for the polyhedral break.
Photos courtesy the author
11sig2.QXD 9/25/06 12:29 PM Page 36November 2006 37
Each wing dihedral angle can be glued with epoxy and secured
with masking tape until the glue cures.
Leon as a World War II pilot with his original Zoomer FF model.
A detailed shot of typical sanding required for the wing dihedral
angles.
Type: Foam RC (converted FF)
Wingspan: 38.5 inches
Wing chord: 7.5 inches
Total wing area: 223 square inches
Dihedral, each tip: 5.625 inches
Overall fuselage length: 25 inches
Stabilizer span: 19 inches
Stabilizer chord (including elevator): 5.75 inches
Stabilizer area: 72 square inches
Motor: AXI brushless 2208/34
Battery requirement: Li-Poly, two-cell, 700-1350 mA
Landing gear: 1/16-inch-diameter wire—single leg (two-wheel option)
Recommended number of channels: Three
Control functions: Rudder, elevator, throttle
Elevator throws: 1/2 inch up, 1/2 inch down
Rudder throw: 3/4 inch left and right
Side thrust: 0°
Downthrust/Upthrust: 0°
Basic materials used in construction: 1/4-inch Dow BlueCor fan-fold foam
Ready-to-fly weight: 9 ounces
Wing loading: 5.77 ounces per square foot
11sig2.QXD 9/25/06 12:39 PM Page 37These airplanes are RC foam replicas of models that Leon designed from 1936 through
1946. All are electric powered! They are similar in construction to the Zoomer.
Left: Famed aviation artist Jim Newman drew this caricature of Leon’s original Zoomer
on a paper napkin during a lunch break between flight sessions.
structure with a simple hatch on the bottom
of the fuselage. The motor was faired into
the fuselage, incorporating a spinner that
smoothed the airflow around the nose of the
aircraft and made for a clean appearance.
A two-blade folding propeller was used
to reduce the frontal drag when the motor
was shut down. The wing and tail used lowdrag
airfoils with simple straight tapered
surfaces that gave a pleasing yet efficient
outline.
To enable such an FF model to have a
steep climbing attitude, most designs used
downthrust, which, although effective,
created extra drag. I built all this into the
design by using a symmetrical airfoil on the
horizontal stabilizer set at a positive angle,
which equaled the necessary downthrust that
would be used.
The wing incidence was also set at a
positive angle so that the wing and stabilizer
would work in unison to equal the usually
needed downthrust. The engine was placed
straight in-line within the nose, giving no
downthrust appearance. The fuselage would
travel at a more normal attitude with the
airflow, thus reducing its drag.
I learned this firsthand when piloting the
full-scale Martin B-26 Marauders. I had
flown most versions of this tremendously
powerful aircraft when the design change
was made to improve its flight
characteristics. Increasing the wingspan by 6
feet and adding slight dihedral made the
airplane easier to fly and enabled it to fly at
a more horizontal attitude. This allowed it to
fly faster with the same power settings.
I also noticed that the B-26’s fuselage
(when observed by flying in formation with
another aircraft) would be more horizontal
than the earlier models with the smaller
wing, instead of looking like it was always
climbing with its nose high. This change in
fuselage attitude (at cruising settings) added
several miles per hour to its flight airspeed.
When translated into a model design, the
same extra efficiency would enable the
Zoomer to climb faster than most models—
and it did!
At one event the Zoomer was calculated
to have climbed 1,500 feet in 30 seconds,
which translates to 3,000 feet per minute—a
hefty performance! The model even
incorporated a small trimmable rudder for
easier flight trim.
The design was popular, and it was
produced in kit form in both sizes. Tens of
thousands were produced and sold.
With the advent of electricity—thanks to
Benjamin Franklin with his kite, Guglielmo
Marconi with his radio, and a great number
of ingenious fellow modelers—we can now
fly these FF designs with an added
advantage of controlling their flight paths
with radio control.
We went several steps further with the
Zoomer and used the latest technology of
Li-Poly batteries, rotary brushless motors
with miniaturized receivers, and servos for
controls. We even used the latest in sheet
foam board technology in this design.
It has been developed to have a high
level of efficiency, low cost, and an easy-toassemble
structure by my good friend Frank
Pisano, who collaborated with me on this
article.
CONSTRUCTION
The construction is simple. We used 1/4-
inch Dow BlueCor fan-fold foam, although
any comparable material can be substituted.
You can find the BlueCor at Lowe’s home
supply or similar stores.
The cost of the foam you actually need is
approximately $2, for less than one of the 24
fan-fold sheets that come in the package. So
please let this encourage you to make this
enjoyable step and build and fly this
Zoomer. You can make more than two
dozen from one package of foam! (If you
have some friends you want to fun-fly with,
make several models at once.)
The plans show the wingspan to be 38.5
inches with a wing area of 223 square
inches. This was scaled down from the
original size so the complete model would
weigh approximately 9 ounces with a twocell,
700-1350 mA Li-Poly battery and a
typical rotary brushless motor: a Hobby
Lobby AXI 2208/34, Hacker A20-22L, or
equivalent.
The wing loading comes out to 5.77
ounces per square foot, making for a
sprightly performing model that will climb
for high altitude yet glide graciously. We
tried several models with different sizes and
weights, and we found this to be optimum.
With a 15-second motor run, this Zoomer
will climb almost out of site.
The Zoomer can be flown at any local
field/park since it is quiet and can make
tight turns to keep it within viewing
distance. This is unlike the other foamies
that hover around endlessly between crashes
and have become almost indistinguishable.
The Zoomer will give you a thrill that
will make your friends envious of its flight
consistency and ease of control. Remember
that this is basically an FF design, and you
will be piloting it around the skies. It will
not get you into trouble; it can fly itself!
We urge you to color the underside of
your model’s wingtips so you can see it
easily when you are flying it in the “wild
blue yonder.” The bright-colored wing
undersurface can save an airplane.
We suggest bright (neon or fluorescent)
orange for excellent visibility. We use
Fluorescent Orange Solartrim trim sheets
since the material is self-adhesive, light, and
easy to apply. Using it only on the bottom of
the wingtips provides enough visibility. And
don’t forget to put your name and telephone
number on your Zoomer—for when you
may let it zoom up and out of sight.
This model has been flown indoors
several times, using low to medium throttle
settings. It is stable and makes graceful
38 MODEL AVIATION
11sig2.QXD 9/25/06 1:10 PM Page 38November 2006 39
See page 183 for Full-Size Plans listing
11sig2.QXD 9/25/06 1:11 PM Page 39turns. This aircraft is not designed to loop or
do rolls; enjoy the thrill of its spectacular
climb and transition into a gentle flat glide,
and then aim it to land right at your feet. The
Zoomer will do it. Try this until you become
proficient enough to enjoy doing it
consistently.
Flights of 15-45 minutes are normal, and
longer flights are possible when there is lift
out there—even off of a treeline at your
park. Be careful with warm air; the Zoomer
really zooms.
This version of the model features a
removable wing held in place with rubber
bands for ease of transportation and damage
resistance. The plans show the full-size
model with notes on its construction.
Basic tools and materials to be used are a
knife; a sandpaper block; cyanoacrylate;
five-minute epoxy; masking tape; 1/32, 1/16,
and 1/8 plywood; a couple strips of 1/16 x 1/4
basswood or hard balsa; and 1/16-inchdiameter
wire for the landing gear. You can
purchase strips of basswood at your local
hobby shop or neighborhood art-and-craft
store.
We show the original single-wheel
landing gear and an optional two-wheel gear.
All the parts are shown on the plans with
necessary fittings and wheel(s).
We even show an optional simple motor
beam mounting feature, which will enable
you to substitute a lower-cost brushed motor
and controller—at a small sacrifice of a
minor weight increase. You can then enjoy
comparable performance at a lower cost.
Start by cutting all parts to shape. Cut
and assemble the landing-gear socket first
using cyanoacrylate. When employing epoxy
to assemble any parts of the Zoomer, apply it
sparingly to minimize weight. Bevel 1/8 inch
from the bottom edges of the horizontal
stabilizer and one side of the vertical fin.
Add basswood stiffeners to each control
surface with a light coat of epoxy. Use clear
packing tape for the hinges, on both sides of
the movable surfaces.
Place stabilizer and elevator surfaces flat
on a bench (with the bevel gap on the
bottom) with a 1/32 inch wire or dowel
between surfaces to create a gap of 1/32 inch.
Press hinge tape in place over both surfaces.
Remove the wire/dowel and then fold
both surfaces in the opposite direction to
apply a second piece of tape to complete the
hinge. Press and rub the tape firmly to secure
it. Use the same process for the vertical
control surfaces before gluing the horizontal
surfaces in place.
Cut the wing panels to size and make the
wing halves, airfoil shape, and dihedral as
shown in the accompanying photos. Crease
the foam wing panels, as shown, in six 1/2-
inch increments to make this novel airfoil.
This process makes an efficient wing with
light weight and tremendous strength. The
photo sequence will walk you through the
wing assembly.
The plans show a new feature that makes
the wing stronger and less prone to minor
scrapes with foliage and/or rough handling.
A short piece of 1/8-inch-inside-diameter
brass (or aluminum) tubing and two skewers
imbedded and epoxied into the LE add
considerable strength and airfoil efficiency
to the Zoomer wing. Four keys locate the
wing position for consistent performance
settings.
You can use masking tape to hold all
parts together while the epoxy sets. Do one
assembly at a time as the epoxy dries. All
incidence and motor-thrust settings are built
in. The photographs show the location of the
motor, controller, battery, servos, etc.
The receiver, motor controller, and
battery are held to the fuselage with Du-Bro
Hook and Loop Mounting Material (product
348). The servos are mounted with Du-Bro
Double Sided Tape (product 634).
We used Du-Bro Micro Control Horns
(product 848) and the Micro Push Rod
System (product 847) to connect to our two
Polk’s Hobby small X-Micro servos. We
used our Polk’s Seeker 6 dual-conversion,
1/2-ounce receiver because of its light
weight, small size, and phenomenal range.
This completes our installation. Servos
should be set to allow 3/4-inch rudder throw
and 1/2-inch elevator throw. Locate
components as shown in the photos. The
balance point, although noncritical, should
be approximately 50% back from the wing
LE.
The original model used the Hobby
Lobby AXI 2208/34 motor and Jeti 8-amp
40 MODELcontroller or Castle Creations Phoenix-10
controller with an APC 10 x 4.7 Slow Flyer
propeller for amazing performance. Several
newer motors have become available since
then and can easily be adapted to the Zoomer
because of the flexibility and simplicity of its
design.
For a lower-cost power package we used
a GWS 350C-C gearing brushed motor and
Castle Creations Pixie-20 controller with the
same APC 10 x 4.7 Slow Flyer propeller. We
built and flew both versions. There isn’t a
great difference in performance between the
two power units, but the brushless package is
sprightlier with slightly less weight.
Bench-test everything before taking the
model out to fly. Make sure the control
surfaces are set properly and that the Zoomer
balances at the suggested position.
This design has an “automatic pilot”
designed into it and will fly by itself, but
avoid severe gusts, which can cause damage
because of the aircraft’s light weight. Upon
launching, the Zoomer will zoom up in a fast
climb and rotate by itself as it spirals upward.
Use gentle control input under power
since the Zoomer really will fly by itself. In a
glide it can make tight turns because of its
inherent stability, and landing at your feet
will be a common happening!
Keep ’em flying! MA
Leon Shulman
Edition: Model Aviation - 2006/11
Page Numbers: 35,36,37,38,39,40,42
November 2006 35
A legendary
modeler’s equally
legendary design
translates into
a peppy RC
electric foam
aircraft
BY LEON SHULMAN
The Zoomer climbs out after making a
flyby for the camera. This model will be
available as an RTF from Polk’s Hobby.
“DESIGNED TO CLIMB” was the title of
an article that Air Trails magazine published
in 1945. It introduced the Zoomer to the FF
modeling community as an evolution of
several FF designs of that era.
As an ardent FFer and designer I wanted
to get the optimum performance from my
models. As an active competitor I studied
the competition and knew that besides
consistent performance I needed a clean,
aerodynamic design that would enable my
aircraft to climb as quickly as possible with
the allowable motor run.
This model design embraced the
minimum wing area allowed for the
engine size that was used, with the
lightest possible weight. I designed the
Zoomer in two sizes: a 60-inch
wingspan for class B and small class C
engines (although several were flown
with .60-size engines) and a 36-inch
wingspan for the smaller .19 class A
engines. Both sizes proved to be successful
and won most of the contests in which they
were entered.
The Zoomer’s fuselage structure was
radical and followed that of my previous
design: the Banshee. It was simple, light,
strong, and easy to assemble and repair
when necessary. It allowed for easy
covering with smooth, flowing lines.
Incorporating a single-wheel landing
gear with two subrudders on the horizontal
stabilizer, the Zoomer allowed quick
takeoffs and smooth landings with
minimum drag. Quick access to the ignition
Leon looks happy with the results of the units and batteries was designed into the
foam Zoomer’s test flights.
11sig2.QXD 9/25/06 2:08 PM Page 3536 MODEL AVIATION
The process for producing the airfoil shape for the wing begins
with making spanwise impressions using a straightedge.
This view shows the creases and the
resulting airfoil shape.
In a similar manner, raise and support the inner wing panel at the
polyhedral joint 13/8 inches, and sand for proper angle.
Measure, raise, and support the tip 15/8 inches above the table
for proper wingtip polyhedral, and then sand the center joint
using 320-grit sandpaper.
Six creases at 1/2-inch intervals complete the wing airfoil. This is a
simple process to learn.
Leon uses a #11 X-Acto blade to cut each wing half for the polyhedral break.
Photos courtesy the author
11sig2.QXD 9/25/06 12:29 PM Page 36November 2006 37
Each wing dihedral angle can be glued with epoxy and secured
with masking tape until the glue cures.
Leon as a World War II pilot with his original Zoomer FF model.
A detailed shot of typical sanding required for the wing dihedral
angles.
Type: Foam RC (converted FF)
Wingspan: 38.5 inches
Wing chord: 7.5 inches
Total wing area: 223 square inches
Dihedral, each tip: 5.625 inches
Overall fuselage length: 25 inches
Stabilizer span: 19 inches
Stabilizer chord (including elevator): 5.75 inches
Stabilizer area: 72 square inches
Motor: AXI brushless 2208/34
Battery requirement: Li-Poly, two-cell, 700-1350 mA
Landing gear: 1/16-inch-diameter wire—single leg (two-wheel option)
Recommended number of channels: Three
Control functions: Rudder, elevator, throttle
Elevator throws: 1/2 inch up, 1/2 inch down
Rudder throw: 3/4 inch left and right
Side thrust: 0°
Downthrust/Upthrust: 0°
Basic materials used in construction: 1/4-inch Dow BlueCor fan-fold foam
Ready-to-fly weight: 9 ounces
Wing loading: 5.77 ounces per square foot
11sig2.QXD 9/25/06 12:39 PM Page 37These airplanes are RC foam replicas of models that Leon designed from 1936 through
1946. All are electric powered! They are similar in construction to the Zoomer.
Left: Famed aviation artist Jim Newman drew this caricature of Leon’s original Zoomer
on a paper napkin during a lunch break between flight sessions.
structure with a simple hatch on the bottom
of the fuselage. The motor was faired into
the fuselage, incorporating a spinner that
smoothed the airflow around the nose of the
aircraft and made for a clean appearance.
A two-blade folding propeller was used
to reduce the frontal drag when the motor
was shut down. The wing and tail used lowdrag
airfoils with simple straight tapered
surfaces that gave a pleasing yet efficient
outline.
To enable such an FF model to have a
steep climbing attitude, most designs used
downthrust, which, although effective,
created extra drag. I built all this into the
design by using a symmetrical airfoil on the
horizontal stabilizer set at a positive angle,
which equaled the necessary downthrust that
would be used.
The wing incidence was also set at a
positive angle so that the wing and stabilizer
would work in unison to equal the usually
needed downthrust. The engine was placed
straight in-line within the nose, giving no
downthrust appearance. The fuselage would
travel at a more normal attitude with the
airflow, thus reducing its drag.
I learned this firsthand when piloting the
full-scale Martin B-26 Marauders. I had
flown most versions of this tremendously
powerful aircraft when the design change
was made to improve its flight
characteristics. Increasing the wingspan by 6
feet and adding slight dihedral made the
airplane easier to fly and enabled it to fly at
a more horizontal attitude. This allowed it to
fly faster with the same power settings.
I also noticed that the B-26’s fuselage
(when observed by flying in formation with
another aircraft) would be more horizontal
than the earlier models with the smaller
wing, instead of looking like it was always
climbing with its nose high. This change in
fuselage attitude (at cruising settings) added
several miles per hour to its flight airspeed.
When translated into a model design, the
same extra efficiency would enable the
Zoomer to climb faster than most models—
and it did!
At one event the Zoomer was calculated
to have climbed 1,500 feet in 30 seconds,
which translates to 3,000 feet per minute—a
hefty performance! The model even
incorporated a small trimmable rudder for
easier flight trim.
The design was popular, and it was
produced in kit form in both sizes. Tens of
thousands were produced and sold.
With the advent of electricity—thanks to
Benjamin Franklin with his kite, Guglielmo
Marconi with his radio, and a great number
of ingenious fellow modelers—we can now
fly these FF designs with an added
advantage of controlling their flight paths
with radio control.
We went several steps further with the
Zoomer and used the latest technology of
Li-Poly batteries, rotary brushless motors
with miniaturized receivers, and servos for
controls. We even used the latest in sheet
foam board technology in this design.
It has been developed to have a high
level of efficiency, low cost, and an easy-toassemble
structure by my good friend Frank
Pisano, who collaborated with me on this
article.
CONSTRUCTION
The construction is simple. We used 1/4-
inch Dow BlueCor fan-fold foam, although
any comparable material can be substituted.
You can find the BlueCor at Lowe’s home
supply or similar stores.
The cost of the foam you actually need is
approximately $2, for less than one of the 24
fan-fold sheets that come in the package. So
please let this encourage you to make this
enjoyable step and build and fly this
Zoomer. You can make more than two
dozen from one package of foam! (If you
have some friends you want to fun-fly with,
make several models at once.)
The plans show the wingspan to be 38.5
inches with a wing area of 223 square
inches. This was scaled down from the
original size so the complete model would
weigh approximately 9 ounces with a twocell,
700-1350 mA Li-Poly battery and a
typical rotary brushless motor: a Hobby
Lobby AXI 2208/34, Hacker A20-22L, or
equivalent.
The wing loading comes out to 5.77
ounces per square foot, making for a
sprightly performing model that will climb
for high altitude yet glide graciously. We
tried several models with different sizes and
weights, and we found this to be optimum.
With a 15-second motor run, this Zoomer
will climb almost out of site.
The Zoomer can be flown at any local
field/park since it is quiet and can make
tight turns to keep it within viewing
distance. This is unlike the other foamies
that hover around endlessly between crashes
and have become almost indistinguishable.
The Zoomer will give you a thrill that
will make your friends envious of its flight
consistency and ease of control. Remember
that this is basically an FF design, and you
will be piloting it around the skies. It will
not get you into trouble; it can fly itself!
We urge you to color the underside of
your model’s wingtips so you can see it
easily when you are flying it in the “wild
blue yonder.” The bright-colored wing
undersurface can save an airplane.
We suggest bright (neon or fluorescent)
orange for excellent visibility. We use
Fluorescent Orange Solartrim trim sheets
since the material is self-adhesive, light, and
easy to apply. Using it only on the bottom of
the wingtips provides enough visibility. And
don’t forget to put your name and telephone
number on your Zoomer—for when you
may let it zoom up and out of sight.
This model has been flown indoors
several times, using low to medium throttle
settings. It is stable and makes graceful
38 MODEL AVIATION
11sig2.QXD 9/25/06 1:10 PM Page 38November 2006 39
See page 183 for Full-Size Plans listing
11sig2.QXD 9/25/06 1:11 PM Page 39turns. This aircraft is not designed to loop or
do rolls; enjoy the thrill of its spectacular
climb and transition into a gentle flat glide,
and then aim it to land right at your feet. The
Zoomer will do it. Try this until you become
proficient enough to enjoy doing it
consistently.
Flights of 15-45 minutes are normal, and
longer flights are possible when there is lift
out there—even off of a treeline at your
park. Be careful with warm air; the Zoomer
really zooms.
This version of the model features a
removable wing held in place with rubber
bands for ease of transportation and damage
resistance. The plans show the full-size
model with notes on its construction.
Basic tools and materials to be used are a
knife; a sandpaper block; cyanoacrylate;
five-minute epoxy; masking tape; 1/32, 1/16,
and 1/8 plywood; a couple strips of 1/16 x 1/4
basswood or hard balsa; and 1/16-inchdiameter
wire for the landing gear. You can
purchase strips of basswood at your local
hobby shop or neighborhood art-and-craft
store.
We show the original single-wheel
landing gear and an optional two-wheel gear.
All the parts are shown on the plans with
necessary fittings and wheel(s).
We even show an optional simple motor
beam mounting feature, which will enable
you to substitute a lower-cost brushed motor
and controller—at a small sacrifice of a
minor weight increase. You can then enjoy
comparable performance at a lower cost.
Start by cutting all parts to shape. Cut
and assemble the landing-gear socket first
using cyanoacrylate. When employing epoxy
to assemble any parts of the Zoomer, apply it
sparingly to minimize weight. Bevel 1/8 inch
from the bottom edges of the horizontal
stabilizer and one side of the vertical fin.
Add basswood stiffeners to each control
surface with a light coat of epoxy. Use clear
packing tape for the hinges, on both sides of
the movable surfaces.
Place stabilizer and elevator surfaces flat
on a bench (with the bevel gap on the
bottom) with a 1/32 inch wire or dowel
between surfaces to create a gap of 1/32 inch.
Press hinge tape in place over both surfaces.
Remove the wire/dowel and then fold
both surfaces in the opposite direction to
apply a second piece of tape to complete the
hinge. Press and rub the tape firmly to secure
it. Use the same process for the vertical
control surfaces before gluing the horizontal
surfaces in place.
Cut the wing panels to size and make the
wing halves, airfoil shape, and dihedral as
shown in the accompanying photos. Crease
the foam wing panels, as shown, in six 1/2-
inch increments to make this novel airfoil.
This process makes an efficient wing with
light weight and tremendous strength. The
photo sequence will walk you through the
wing assembly.
The plans show a new feature that makes
the wing stronger and less prone to minor
scrapes with foliage and/or rough handling.
A short piece of 1/8-inch-inside-diameter
brass (or aluminum) tubing and two skewers
imbedded and epoxied into the LE add
considerable strength and airfoil efficiency
to the Zoomer wing. Four keys locate the
wing position for consistent performance
settings.
You can use masking tape to hold all
parts together while the epoxy sets. Do one
assembly at a time as the epoxy dries. All
incidence and motor-thrust settings are built
in. The photographs show the location of the
motor, controller, battery, servos, etc.
The receiver, motor controller, and
battery are held to the fuselage with Du-Bro
Hook and Loop Mounting Material (product
348). The servos are mounted with Du-Bro
Double Sided Tape (product 634).
We used Du-Bro Micro Control Horns
(product 848) and the Micro Push Rod
System (product 847) to connect to our two
Polk’s Hobby small X-Micro servos. We
used our Polk’s Seeker 6 dual-conversion,
1/2-ounce receiver because of its light
weight, small size, and phenomenal range.
This completes our installation. Servos
should be set to allow 3/4-inch rudder throw
and 1/2-inch elevator throw. Locate
components as shown in the photos. The
balance point, although noncritical, should
be approximately 50% back from the wing
LE.
The original model used the Hobby
Lobby AXI 2208/34 motor and Jeti 8-amp
40 MODELcontroller or Castle Creations Phoenix-10
controller with an APC 10 x 4.7 Slow Flyer
propeller for amazing performance. Several
newer motors have become available since
then and can easily be adapted to the Zoomer
because of the flexibility and simplicity of its
design.
For a lower-cost power package we used
a GWS 350C-C gearing brushed motor and
Castle Creations Pixie-20 controller with the
same APC 10 x 4.7 Slow Flyer propeller. We
built and flew both versions. There isn’t a
great difference in performance between the
two power units, but the brushless package is
sprightlier with slightly less weight.
Bench-test everything before taking the
model out to fly. Make sure the control
surfaces are set properly and that the Zoomer
balances at the suggested position.
This design has an “automatic pilot”
designed into it and will fly by itself, but
avoid severe gusts, which can cause damage
because of the aircraft’s light weight. Upon
launching, the Zoomer will zoom up in a fast
climb and rotate by itself as it spirals upward.
Use gentle control input under power
since the Zoomer really will fly by itself. In a
glide it can make tight turns because of its
inherent stability, and landing at your feet
will be a common happening!
Keep ’em flying! MA
Leon Shulman