Piper’s “economy”
design makes a
great-flying
Rubber Scale
subject.
n Dave Robelen
PIPER
Vagabond
A few tissue trim pieces, a Piper logo, and some pen-and-ink control surface separations add life to this classic.
The author’s daughter Lill sends dad’s creation
off on another successful hop. Model has a Peck-
Polymers eight-inch propeller.
32 MODEL AVIATION
he Piper Aircraft Corporation
introduced the Vagabond in 1948, as
an effort to produce a true two-place
economy airplane.
The Vagabond shared parts with its
ancestor, the J-3 Cub, including wing panels
(shortened), tail surfaces, and a variety of
hardware.
Starting with the PA-15 model, the
Vagabond was a “bare bones” economy
version with a 65-horsepower engine, single
controls, and no landing-gear shocks.
Soon following, the PA-17 had dual
controls and landing-gear shocks, along
with various other amenities. This is the
version I chose to model.
The Vagabond has performed
extremely well for me as a Rubber Scale
model, winning Duration contests and
placing second at the big Flying Aces
Club (FAC) Nationals at Geneseo NY.
January 2001 33
Details add a great deal. Note the simulated cylinder heads in the cowl openings, the air scoop, and the bungee cords.
Because of the minimal amount of structure, this model can be built extremely light. It builds quickly, too!
The extra time required to apply logos and surface detailing really pays off. The
laminated surfaces are easy to make.
Photos courtesy the author Graphic Design by Jill Ann Cavanaugh
34 M ODEL AVIATION
My early versions were built from Walt
Mooney Peanut plans. Although they flew
extremely well, there was too much
compromise in the design for it to be
successful in a true Scale event.
After shopping around, I found a decent
Vagabond three-view from Micro-X. This
model was developed from that drawing.
If you are serious about competition, check
out the material available from Scale Model
Research before beginning construction. It can
be frustrating to build a Scale model for
competition, only to find a lack of
documentation for the version you built.
This documentation must include
photographs to be complete (and the model
must match the photographs).
The model I am presenting uses some
hefty wood sizes for a serious Free Flight
Scale model, but you can still build it plenty
light, by carefully choosing suitable wood.
With all the parts assembled, there’s no mistaking the Piper heritage. Be sure to block-sand the structure carefully.
The outlines of the tail assemblies and wingtips are made from wet-formed and
laminated balsa strips. The strips are held in place on the forms with tape.
When removed from the forms, the balsa strips will retain their
new shape. The text outlines the complete technique.
The fuselage crutch employs the traditional built-up stick-type
construction. It’s simple, light, and strong!
The strip wood in the hobby racks is
generally too heavy for our purposes, so buy a
few nice sheets and strip your own sticks. There
are several fine wood-stripping tools on the
market, or you can do as I do: use a straightedge
to guide the blade while stripping.
There is only one deliberate change to the
design as presented—a slight enlargement of
the horizontal tail. The original-size tail can
be used, but it will be very sensitive to rubber
bunching, and balance in general.
The rest of this model follows the scale
outlines as closely as I could manage.
At the beginning of your project, decide
if this is going to be a “serious” Rubber
Scale entry or just a very enjoyable sportflying
model.
This decision affects the way you detail
your model, and it affects things such as the
choice of wheels.
A proper Rubber Scale entry requires
January 2001 35
Type: Free Flight Rubber Scale
Wingspan: 26 inches
Flying weight: 1.22 ounces
Construction: Stick and sheet balsa
Covering/finish: Tissue and spray lacquer
PiPer
Vagab
Full-Size Plans Available —see page 189
that you fashion foam wheels, matching the
aircraft version you have chosen, and add all
those little point-getting details around the
nose and cowling.
Whichever way you choose to use your
model, please build the Vagabond as light as
you can, for nice, gentle flight qualities. It is
a mistake to reinforce a model against the
possibility of a crash, because it almost
assures one.
Since there are no deliberate warps
necessary, make every effort to keep your
model straight and true. If you are new to
laminated outlines, this will be good
exercise.
Choose a flat and clear work area, with
good lighting and minimum distractions. I
do most of my projects on an old
conference table, with a flourescent shop
light over it.
Take your time and enjoy the construction,
making a “project” of each small part. This
way, you will do yourself proud as it all
comes together.
CONSTRUCTION
Begin with the laminated parts as a
warmup.
Strip enough 3⁄32-inch-wide lengths from
a light, flexible sheet of 1⁄32 A- or A-B-grain
balsa to construct all the laminated parts.
The A- or A-B-grain balsa has long,
straight fibers, and will mold, or form,
easily. Do not use C-grain balsa for these
operations; it will break or crack when it’s
bent around the forms.
It is easy to distinguish A- and A-B-grain
from C-grain, which will have a short grain
that resembles fish scales.
There is a variety of choices for form
materials. I usually select the crummiest
balsa I can find in the hobby shop rack, then
try to convince the dealer to discount it, to
clear it out of stock!
Cut the form outlines to conform to the
inside curve of the parts, and make the
forms slightly longer than the finished parts.
Rub a bar of soap around the edges of the
forms, and they are ready. (The soap
prevents the glued strips from sticking to the
forms.)
Things can get busy during the forming
process, so pick a time with the least chance
of distractions.
Get a pot of hot water with a capful of
ammonia mixed in, for soaking the strips.
This combination makes the wood fibers
more pliable.
I use masking tape to hold the laminated
strips to the forms. Tear off a bunch of short
tape pieces, and lightly stick them where
you can reach them easily when you are
ready for them.
Put the balsa strips in the pot so that they
are covered with the hot water and ammonia
solution. You will probably need a couple
light weights, to keep the wood submerged.
If you are working in the kitchen, it is
best to do all this alone and clean up
carefully when you are finished.
I use Elmer’s® white glue for the
following task.
Start with a wingtip, and pull one strip
from the ammonia/water solution, quickly
coating it with a very light bead of glue on
one side. Keep moving, and pull three
more strips out, until you have a sandwich
of four strips with a bead of glue between
each one.
Starting at one end, place the strips
against the form and wrap masking tape
tightly around the end. Squeeze the strips
together and pull them around the form,
keeping tension as you go. Use a piece of
tape to fasten that end.
Finish the remaining edges. Put the wet
parts in the oven on a low setting, and give
them roughly an hour to dry.
This is a good time to clean the kitchen,
and scrub that pot well.
When the parts are dry, pull them out of
the oven and carefully peel the tape away. If
you did the job right with the soap, the strips
will “pop” free from the forms.
Set the laminated parts aside, and make
the rest of the wing parts. Trim the trailing
edge to shape, sand it smooth, then check it
carefully for warps or bows.
Strip a leading edge and a spar, and cut
the ribs out using a template. Stack the ribs,
and push a couple pins through the pile.
Sand the whole stack smooth, and to the
same shape.
The 1⁄16 balsa goes at two tip ribs and the
two center ribs. The remainder of the ribs
are from 1⁄32 balsa stock.
Smooth the plan down over a flat board
that can take pins easily, and cover it with
36 M ODEL AVIATION
waxed paper. Pin the trailing edge in place,
and using several ribs as spacers, pin the
leading edges down.
Fit the rest of the ribs in place, and glue
each one with a spot of gap-filling
cyanoacrylate (CyA) glue. Affix the gussets
in place with a minimal amount of CyA,
then trim and fit the laminated tip bows. Lift
the tip bows to the angle shown on the plan,
then glue them in place.
When the glue is dry, cut almost
through the trailing edge from the top,
and lift the wing panels to the proper
dihedral angle. Support them with scrap
balsa pieces, pinning them securely in
place while you trim and glue the spar to
the ribs.
Install the vertical brace between the two
center ribs. Glue the gussets in the leading
edge corners, and you’ve done it.
When all is dry, lift the wing off the
board and block-sand it carefully. Reglue
anything that looks suspicious. Set the wing
aside for now.
Tail: Try to find stiffer-than-average wood
for the tail strip-wood, and cut and fit things
together, pinning as needed.
Use just enough adhesive to hold things
without forming glue puddles or fillets. Glue
is heavy, and an excess amount will not
make the joint any stronger.
Block-sand the tail surfaces smooth
when dry, and round the edges neatly. Put
them aside with the wing.
Fuselage: Strip some light, flexible stock
for the basic frame. Assemble two sides on
the dark lines depicted on the plan, noting
the wider balsa strips at the front of the
cabin and rubber anchor post.
When all is dry, block-sand both surfaces
of each fuselage side smooth. Look at the
cross-sections, and note that two vertical
stations are cracked and reglued with a
slight bow. Please make only one right and
one left!
Assembly of the sides starts with the two
top crosspieces between the wing, which are
the same length. It will be a big help if you pin
things down over the top view for this step.
Install a temporary crosspiece at the
landing-gear station. Check that everything
is square, and cut partway through the
longerons, where they bend to meet at the
tail. They should form a straight line from
the cut to the tail post.
Cut and fit the rest of the crosspieces
from the wing aft.
Cut the two nose crosspieces, and pull
the sides in to contact them. Crack the
longerons if needed, to get a straight line
from the cabin to the nose. Glue these
crosspieces in place, then fit the nose
bulkheads, gluing as you go. Install the
bulkhead at the instrument-panel station.
Scout out some flexible 1⁄32 balsa sheet,
and cover the top of the nose. (You may
need to join two pieces of 1⁄32 balsa sheet for
this operation). This is a good place to use
some of that nice, slow-drying Elmer’s®
white glue. Masking tape will also be a big
help here. Work slowly, and cover the areas
of the nose indicated on the plan.
Once the glue has dried, trim and sand
the sheeting to a perfect fit. Install the 1⁄64
plywood nose bulkhead.
Find a soft balsa block for the bottom
nose piece; rough-shape the outside and
the angle needed for it to fit properly
against the nose bulkhead. Gouge the balsa
from the inside of this block, until you
achieve a 1⁄8-inch wall section. Glue the
block in place.
When the glue is dry, sand the entire
nose section to a smooth contour.
Bend up the 1⁄32-diameter wire landing
gear, and sandwich it between layers of 1⁄16
balsa. Glue this assembly together with gapfilling
CyA, and squeeze firmly enough that
the wire mashes into the wood until the two
pieces meet.
Pop out the temporary crosspiece, and
glue the landing-gear assembly in place.
You have some choices on the nose
block. If you are going to fly the
Vagabond for fun, you might skip the
recessed cylinder openings and paint these
areas flat black.
However, if this is going to be a contest
model, spend some time on this important
area; carefully match the nose to your
research photographs and three-views.
Glue the 3⁄16 balsa nose plug onto the
nose block, and drill for the nose
bearing. Fit the nose block to the
fuselage, and carefully blend things with
the sanding block.
Check the plan for position, and install
the 1⁄16 balsa stringers.
Make the landing-gear legs, wing struts,
simulated engine air scoop, and any other
details you will cover with tissue.
Covering/Finish: I shouldn’t tell you much
about covering your model with tissue, since
I have more problems than any two people I
know! Check out some good articles on the
subject, and come back.
However, I will mention materials that
have worked well for me.
Esaki tissue does a great job, and has
good wet strength. I adhere it to the airframe
with Elmer’s® School Glue (gel stick), from
the stationery department. It stays sticky a
while, and only a thin film is needed.
Rubbing alcohol misted on with a nasalsprayer
is adequate for tightening the tissue.
A couple thin coats of Krylon® Crystal
Clear spray lacquer provides a decent finish.
Pin the wings and tail down whenever they are
drying, to prevent warping. Acetone brushed
through tissue trim will hold it in place nicely.
A fine-tip Sharpie® pen against a
straightedge is ideal for adding control
surface outlines, door openings, etc.
Assembly:Make up the propeller shaft with
some washers and all the necessary bends,
and make sure things spin freely. Cut and
install the aluminum tube rear rubber hanger.
Install the wing now. I use slower-drying
wood glue here, to allow some working and
alignment time. Check from all angles, to
make sure that things are perfectly aligned
before gluing. Let this assembly dry
thoroughly before proceeding.
Install the instrument panel and the two
cabin braces.
Before mounting the windshield, I use a
felt-tip marker to color all exposed wood, to
match the tissue.
Make a windshield template from
notebook paper. Hold the template in place,
and mark and trim until it fits perfectly.
When you are satisfied with the fit, transfer
the shape to sheet acetate, and cut it out
carefully. (I found my acetate at a mall craft
store.)
The gel school glue is excellent for
attaching the windshield. Use very little
glue and many pins, and let it dry
thoroughly.
Mount the tail with small spots of wood
glue, and check the alignment all around.
Adhere the vertical tail with glue at the tail
post only, to allow for adjustment.
Finish the landing gear, making sure the
wire legs can flex backward without
breaking anything. Install the wing struts
and tail-wheel assembly, and you are on the
home stretch.
If you are thinking about competition,
now is the time to add rigging wires,
control cables, and all those neat nose
details.
Examine the whole model, and remove
any warps or other problems that might have
crept in.
Make the rubber motor from four 30-
inch-long strands of 1⁄8 Tan II rubber, and
tension it so it does not flop around. Check
the balance against the plan, and add weight
as necessary to correct.
Flying: Hand-gliding a model like this is
useless, and might even break it!
Start with just enough winds in the
rubber to have a powered glide. I like to see
the Vagabond go basically straight ahead,
with no stall and definitely no diving.
Add more winds, and try again.
Look for a very wide right circle when
the model has enough power to climb. Use
a combination of thrust adjustments and
rudder turn to achieve this flight pattern.
Add more power, until it runs out with
some altitude. Assuming your propeller is
freewheeling correctly, make the final glide
adjustments with balance changes.
The Vagabond will never be a floater,
but it should not dive for the ground either.
The best results I have achieved are with a
long, gentle motor run, as opposed to trying
to “blast” the Vagabond to altitude.
Have a good time with your Vagabond, and
let me know if I can be of help. MA
Dave Robelen
Rt. 4, Box 369
Farmville VA 23901
