Marin Aero Club (M.A.C.) comprises a group of fliers who meet
regularly to fly model aeroplanes powered by rubber, electric or CO2.
Indoor events are held monthly year round, and also outdoors in the
summer. The group is very informal as we have no officers or dues and
stress that it is more important to have a good time rather than
put up a good time. As the M.A.C. has been in existence since
about 1948 (in Marin County, just north of San Francisco) it has
certainly met a local need.
This is a guideline to those returning or
beginning to build and fly balsa wood and tissue covered model planes.
It is not intended to be a comprehensive source of instruction, but
instead to familiarize one with some of the concepts of building and
flying these delightful models. It is also aimed at the M.A.C. situation
with access to a gymnasium and an outdoor field. Scale and non scale
models are flown. Fuse dethermalizers are not permitted due to
fire hazards and noise.
M.A.C. members welcome you and are very happy to
assist you with guidance as required. The current flying schedule, maps
to the flying sites and the latest information are all available at the
Marin Aero Club
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- "Building and Flying Indoor Model Aeroplanes" by Ron
Williams is an excellent book and well worth reading. Dedicated to
lightweight duration models this book will teach you many lessons
valuable to any type of models. Long out of print, this wonderful
volume is now available again. The 1984 second edition has been
reprinted (ISBN 978-0-615-20203-7), and is available from
for $24.95 plus shipping and handling. More information is available
at this web
- "Rubber Powered Model Aeroplanes" by Don Ross. About $15.
A good overall guide to building and flying a wide range of models.
Don has also published a followup volume, "Flying Models,
Rubber, CO2, Electric & Micro Radio Control" This is also
- "Hey Kid Ya Wanna Build A Model Aeroplane?" by Bill
Warner. A detailed guide to building, trimming and flying two simple
rubber powered models available as kits. Two other books follow in
the series and cover the Sky Bunny and Flying Aces Moth. While now
out of print, they are often seen in local libraries.
- "Indoor Scale Model Flying" by Fred Hall is a concise
guide to many areas of concern, i.e., model selection, construction,
propellers, rubber choice and trimming. About $8.
- "Indoor Flying Models" by Lew Gitlow is a worthy
substitute for the Williams book above. Contact
Indoor Model Supplies or
These, and other books available from Hannan's
Runway, P.O. Box 210, Magalia, CA 95954. Tel. No. (916)-873-6421.
They also have a web site
with secure online ordering. Bill Hannan has authored a series of
excellent books emphasizing "Peanut" class 13" span scale models.
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- We suggest starting with a very simple precut model such as the
Sleek Streak sheet balsa model available in hobby shops, toy stores
and larger drug stores. This provides a good way to learn the
rudiments of trimming to control turning and climbing and the
effects of changes in rubber size. Surprising performance can be had
with these simple models.
- Next in complexity is a stick model with a built up balsa stick
and tissue covered wing and tail. This substantially increases
flying time over the preceding sheet models. Many designs are
available. The Peck R.O.G. (Rise Off Ground) is covered in Bill
Warner's first book and is available as a kit from Peck. A similar
model is the Jetco ROG.
Click for online plans.
- The next step up is to build a model with a built up fuselage
instead of a "stick" fuselage. We cannot emphasize too strongly that
it is too early to build a scale model as these are trickier to
build, harder to fly, more vulnerable to damage and could be very
discouraging, whereas we can (almost !!!) guarantee success if your
first built up fuselage model is a
"Pussy Cat". Although only 12" wing span, if built lightly it
can fly for over a minute in the gymnasium and can fly "Out Of
- After the Pussy Cat is satisfactorily built and flown, we advise
building a Bostonian class model. This is a 16" span model in a wide
range of designs (ask for plans) resembling full size planes but
with proportions better suited to easy trimming and stable flying.
- Selection of your first scale model design is very important to
avoid discouragement as many full size planes make very poor flying
scale models. As a general guide, select a high wing monoplane with
a long nose (for better balance) and a minimum of struts and complex
landing gear. Planes such as the Nesmith Cougar, Lacey, Fike or
early Cessnas can be built from plans or kits.
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Many local hobby shops carry a range of supplies
suitable for our needs, including many items from the Peck catalog
- Peck Polymers, P.O. Box 710399, Santee, CA 92072-0399 (619)
448-1818. Catalog for $4 lists kits, plans, balsa, tissue, props,
wheels, wire, bearings and more. Quite possibly the best individual
supplier for our needs.
- Easy Built Models makes a wide range of older design, mostly
scale planes. Kits are inexpensive, light weight, not particularly
great scale, but many fly well. Laser cut Peanuts Piper Cub and
Stinson Reliant fly well and easy to build.
- Indoor Model Supply. I.M.S. is now a stable mate of Peck
Polymers. All the old goodies can be had at
- Micro-X, P.O. Box 1063, Lorain, OH 44055. (216) 282-8354.
- Aerodyne and Old Time Model Supply, 1924 East Edinger, Santa
Ana, CA 92705.
These three suppliers all carry selections of
indoor materials and some specialized outdoor supplies, as well as plans
and kits. It is well worth sending a SASE and a dollar or two for their
- Micro Mark, 800-225-1066. A good source of modeling tools.
Knives, blades small drills, burrs, clamps, Dremel, etc.
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Materials and Techniques
- Balsa Wood: Long the traditional material for building
models, balsawood is a huge topic that can only be touched upon
here. Take a moment to look at the rack of balsa while first
browsing your local hobbyshop. Selecting wood can be a real science,
but for now, notice that some sheets of wood seem much lighter in
color, and weight, than others. Hold a few sheets of 1/32" or 1/16"
up to a light, and notice the different grain and color banding that
can occur. All of these variations help indicate weight and
strength. They will become more meaningful as you build models.
Balsa can vary in weight from under 4 lbs. per cu. ft. to over 20
lbs., a variation of 5:1. Obviously if weight is important, and it
is, care must be made to choose wood that is strong enough for the
job, but not too heavy. If you want, buy a couple of sheets of
1/32", 1/16" and 1/8" balsa. Try to choose ones that are in between
the extremes of weight available. It isn't critical for now, but a
little care will help.
- Glues: An often debated subject. For gluing balsa some
use balsa cement, others use white P.V.A. glue and some use CyA. (Krazy
Glue, Hot Stuff, Zap, etc). The CyA is potentially dangerous as it
instantly sticks fingers together and is hazardous around the eyes.
NOT recommended for juniors or the clumsy! However, if CyA is
used, the odorless is preferable as, although more expensive, it
does not irritate the nose and also is compatible with blue foam,
Glues should be applied sparingly. Use only enough so the joint
is as strong as the wood. Additional glue only adds extra weight.
One method is to take a piece of modeling clay about half a golf
ball in size and flatten it with a depression in the center. Place a
disc of waxed paper on the clay and press it down. Pour a little
glue on the wax paper and apply the glue to the balsa with a
toothpick or a piece of thin Teflon tubing available from hobby
Glue sticks, e.g., Ross Purple Stick, UHU Glue Stick, Kidstick,
can be used to adhere paper letters or numbers to tissue. The
peelable, non-permanent glue stick is used where separation is later
required such as applying a printed pattern for wing ribs or formers
to balsa sheet as a template. After cutting out the rib, the paper
can easily be removed. Brands available include Avery Removable Glue
Stic, Dennison Tack a Note, Post-It Restickable Glue Stick.
Tissue can be attached to the balsa structure by applying a clear
liquid glue gel with a small brush to the balsa. Apply the tissue
and smooth down with a finger. If necessary, thin in the bottle with
rubbing alcohol or water. Brands include UHU, liquid Glue Pen,
Roll'n Glue, O'Glue, Dab'n Glue. Do not confuse with solid glue
- Tissue: Use only Japanese tissue and not domestic
tissue. Japanese tissue is stronger, lighter and colors do not run
when wet. Trim tissue after covering with a new sharp double
edged razor blade, cut in half. Careful disection of a disposable
razor can also yeild a suitable blade, but please be careful!
Doping is rarely used for our small models as it adds unnecessary
weight, can add to the warping problem and we don't usually need the
water resistance it provides. Tissue can be lightly shrunk with a
thin mist of rubbing alcohol, applied with a spray atomizer. Many
light weight models are best covered with tissue which is preshrunk.
To preshrink tissue, a partial sheet of tissue is taped with
masking tape around the perimeter, to a picture frame or over a hole
cut in a corrugated cardboard box.
A better frame is made from a piece of Masonite. With a saber
saw, cut a hole in the center about 1" smaller in length and width
than half a tissue sheet. (Hole is about 17" x 11"). Place the
Masonite smooth side up with the loose center in place on a flat
surface, rest the tissue on top and tape down the tissue around the
outside. Lift up the Masonite, (leaving the loose center behind)
support at one or both ends, mist with rubbing alcohol and let dry.
Repeat several times. The Masonite loose center piece supports the
tissue and minimizes wrinkles while taping down.
When tissuing the model, apply in small pieces, and run the
tissue grain direction in the long dimension of wings, fuselage,
stabilizer. Japanese tissue tears more readily in the grain
direction so it is easy to establish grain direction.
- Music Wire: For our purposes, a selection of music wire
from .031" down to .015" or even .010" is required. .031" or .025"
is used for propeller shafts with .025" to .015" for landing gear.
Each increase in wire size doubles the wire weight, so be sure you
need the larger size as you build.
- Aluminum Tubing: Tubing is available in 12" lengths. Use
1/16" O.D. for rear motor pegs on Peanuts and Bostonians and 3/32"
or 1/8" for larger models.
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- Cutting: For cutting, use single edge razor blades and/or
an Exacto knife with No. 11 blades. Keep sharp and replace blades
regularly. A plastic cutting pad is a very useful luxury (about $15
when on sale at Micro Mark) minimizing dull blades.
- Building Board: A piece of Cellotex or similar wood fiber
ceiling material about 12" x 24" from building suppliers makes a
good board for construction.
- Hold Down Pins: T pins are available from hobby stores
and Peck for building purposes. These are used to position balsa
prior to gluing. Do not push pins through the wood. Pin
clamps are plastic "discs" which slide tightly on to T pins to hold
down wood to the building board. Pin clamps are available from Jerry
Nelson Hobby Products. Scraps of balsa can also be used.
Craft stores sell long T pins (2" compared to the standard 1" T
pin) which are useful to position fuselage sides on to the building
board when joining together. A couple of metal blocks about 2"x2"x3"
can be used to hold and square up body sides in conjunction with
long T pins.
- Tweezers & Pliers: Tweezers are used often for
positioning bits of wood while building. Try finding a pair of
"stamp" tweezers with a broad flat blade. This will help prevent
crushing the soft wood.
A small selection of pliers for wire bending is necessary. Needle
nose are very useful, as are a good pair of roundnosed pliers. These
are most useful for prop hooks, and can be tough to find. A good
pair of diagonal cutters will be appreciated as music wire can be
very hard. Cheap cutters will soon develop notches in the blades.
- Sandpaper: This should be the most used tool, perhaps
after a sharp cutting blade. Make sure to get a good selection from
100-320 grits. It lasts a long time on balsa wood, and will really
make a difference in the quality of your work. Empty oval glue
bottles are handy to wrap sandpaper around for shaping concave
edges, e.g., wing tips.
- Clamps: Miniature toy clothes pins about 1" long are
handy to clamp wood when gluing. Also scraps of balsa can be used
with a pin to hold down pieces. A selection blocks is also handy for
positioning pieces as the models become more 3 dimensional. I often
use small transparent plastic boxes filled with pennies.
- Dremel tools are a luxury but good for wheel and spinner
sanding. They are also used for cutting heavier music wire. A good
selection of bits will be appreciated if you make this investment.
- Drill Bit Sets: Sizes from No. 61 (.039") to No. 80
(.0135") are useful, and become necessary for drilling aluminum prop
bearings on stick models and Nocals. About $15 on sale from Micro
Mark. A small pin vise or Dremel is needed to use with these drill
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Propellers & Bearings
Plastic props are very efficient and available in
a wide range of sizes from 4" to 9" or more. For Peanuts, Bostonians and
Dime Scale (16" span) 5" or 6" are customary.
Plastic nose bearings which fit into a 1/8" or
1/4" hole in the nose block are available and small glass beads about
1/16" diameter are used between the prop and nose bearing. For Nocal and
stick models, make a bearing from .030" - .035" aluminum, about 1/8"
Indoor Lightweight Props
For lightweight stick models, Nocals, Seattle 6,
etc. a lightweight prop can be built as follows:
- Hubs: Usually made of hard1/8" or 3/32" square
balsa, to which blades are glued. A clean ball point pen reservoir
can also be used. Insert dowels, bamboo, & toothpick for a snug fit.
Blades are glued to dowel. This provides pitch & adjustment.
- Blades: Using a thin foam disposable cup (not the
3/32" to 1/8" thick expanded bead type), lay your blade template on
the cup as shown, cut out and glue (odorless C.A., or white glue) to
Alternatively, 1/32" or 1/20" balsa can be soaked in water, then
positioned onto a can or bottle about 3" diameter at 15 degrees off
the vertical axis. Wrap with porous cloth (bandage?) to allow
moisture to evaporate, and when dry (overnight), remove and glue to
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Rubber and Winding
- Rubber: F.A.I. Tan 2 is the most popular rubber, and
available in widths of 1/16", 3/32", 1/8" and 1/4". Peanuts and
Bostonians use widths of around 3/32" or 1/8". Determination of the
"best" rubber size is an acquired skill but more experienced
modelers or the books listed earlier will help.
Rubber strippers are available ($100+) to strip 1/4" rubber into
any width. These are certainly a "luxury" tool which can well wait
until the modeling bug really bites. Many experienced modelers have
them and can be quite generous with ther use at a flying session.
Rubber lubrication is important. Use Armor All, Son-of-a-Gun
vinyl restorer or Sil-Glyde silicone grease from auto parts stores.
Tie the rubber knot before lubricating.
A small rubber or plastic sleeve which fits over the rubber,
behind the prop hook helps reduce motor bunching and climbing. Heat
shrink tubing can be used.
- Winding Stooge: When winding, it is customary to use a
holder or "stooge" to hold the fuselage securely by sliding a thin
wire through the rear motor peg tubing. This allows stretch winding
without assistance, and will increase flight times dramatically. For
design ideas, see these in use at a flying meet. A
simple drawing for one is also available.
- Winders: To wind the rubber,
mechanical winders with ratios of 5 to 1, 10 to 1, or 15 to 1
are readily available. Prices go up from about $10 with expensive
ones incorporating a torque meter to provide an indication of the
"power" of the rubber when winding. Counters are frequently
incorporated into a winder.
A hand drill can be used to make a winder though the ratio is
rather low for small rubber. If you decide to go this route,
securely fit a hook by removing the chuck and drilling through
the side of the shaft. A wire hook can be fixed in this hole and
will not pull free while winding.
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- Laminating Wingtips and Fins: Curved outlines such as
rudders can be formed by laminating two or three thin balsa or
basswood strips about 1/32" x 1/20" around a template cut from a
foam plastic plate or foam take out container. Presoaking the wood
in water helps with tight curves. Basswood or bamboo about 1/20"
square can be used without laminating by soaking and bending around
the hot shaft (not the tip) of an electric soldering iron. To
laminate two or three strips, apply glue sparingly with a toothpick.
R.C. 56 glue is suitable for this as it retains flexibility when
dry. Peck catalog lists Basswood in several sizes.
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- Scale Detailing
- Many scale details, e.g., exhausts, wheels, can be made from
blue house insulation foam. This is about 3/4" thick and easily
cut and sanded, so keep a lookout around construction sites.
- Sharpened brass tubing or sharpened sections from an old
telescoping auto antennae are used to cut out small discs from
foam or balsa for scale cylinders, wheel centers, etc. Dummy air
cooled cylinders for scale engines can also be made by screwing
soft balsa into a threaded nut so as to simulate cooling fins.
- Use lightweight materials such as foam or light balsa wheels
instead of heavy plastic ones frequently supplied with kits.
Blue foam wheels can be cut and sanded to a very scale-like
appearance. Use water based acrylic paints or marking pens.
Lightweight hub reinforcements can be punched out with paper
hole punches from 1/64" or 1/32" ply, and glued to the wheel
center. (If CyA glue is used, only use odorless which is foam
compatible). Ply discs are lighter than aluminum tubing. Punches
in 1/8", 3/16" and 1/4" diameter are available.
- Marking pens are handy for small areas of tissue coloring
and do not add weight. Rub on letters are available from art
supply stores and are applied to tissue before the tissue is
applied to the model.
- Landing gear should be formed from bent music wire then
balsa is glued on to provide scale appearance. The wire must be
allowed to "flex" on impact. Usually the wire is run from one
wheel up to the fuselage, then glued and braced with balsa
gussets to the fuselage lower longerons and cross pieces before
forming the opposite side. Customary wire size ranges from .031"
for heavier planes of around 24" span down to .015" for light
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- Plans and Kits
When you visit your local hobby shop, you might find many kits
for scale models. Generally these are not recommended when
starting model flying. We suggest more simple models for getting
your start, including designs like the Jetco ROG, and Dick Baxter's
Pussycat and his low wing Akro. all three of these are available as
free online plans.
Preserve your plan and do not cut it up when building. Many of us
run a photocopy prior to building to preserve the original plan.
Photocopiers can be used to scale a plan up or down. Rib and former
profiles can be photocopied, glued to balsa with peelable glue
stick. Cut out the wood part, and easily peel off the paper
- Low Wingers
As low wing designs tend to be less stable, you might want to
build one or two high wing models first. Dick Baxter's Akro might be
the best low wing design when starting if you can't wait.
We suggest the wing is built in one piece and fit into a cut out
in the body. This is a strong method and avoids the problem of
trying to align each wing half correctly.
It is wise to add more dihedral than on a high winger. One rule
of thumb is for the wing tips to be at at least the same height as
the thrust line.
Some older plans show the stabilizer being built in two halves.
Where possible, revise the design to build as one piece.
Stabilizer adjustment can be provided by incorporating a tapered
slot in the fuselage using balsa shims for adjustment.
Scale models (especially older plans) frequently benefit from a
10% - 15% increase in stabilizer and fin area. Use an enlarging
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- Light Weight is Important!
The importance of building light cannot be overstated. This is
the key to improved flight times as a 10% weight reduction results
in a 15% improvement in flight times. Additionally, because the
plane flies slower, it will be damaged less on impacts.
Factors which influence weight include:
- Balsa selection: Balsa can vary in weight from 4 lbs.
per cu. ft. to as high as 22 lbs., a variation of 5:1, so seek
out lightweight sheets using a pocket postal scale to compare
- Structure: Minimize weight wherever possible by
simplifying the wood structure, perhaps deleting some wood or
substituting smaller sizes. Reducing the weight of the tail
section is important as most scale planes are tail heavy and the
"leverage" effect of the tail and fuselage rear behind the
Center of Gravity means that an extra gram at the rear requires
about 3 more grams on the nose to counterbalance.
- Plastic Propellers: As your models get lighter, you
will find that these propellers can be quite heavy. A single
edged razor blade can be used to scrape the blades to reduce
weight significantly. Often times the blades become nearly
transparent in the search of "lightness".
- Scales are very useful to aid in lightweight construction.
See examples of an easy to build spring scale and other
types in common use.
The Micro-Air wooden beam balance scale kit is inexpensive.
Micro Air, P.O. Box 1129, Richland, WA 99352.
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Experienced help will save a lot of frustration. A
step flying and trimming guide is also available. Study it!!
However, in summary:
- Warps have a varying influence on flight characteristics,
depending on flight speed, e.g., initial climb under power, or
cruise, so check very carefully and remove them by steaming or mist
lightly with rubbing alcohol. They can appear, especially if high
temperatures, as in a car, cause tissue to shrink.
- Glide the model without the propeller and make
appropriate adjustments or add weight. We are looking for a gentle
glide without climbing or diving. A slight turn is desirable to
prevent long chases. Try a tacky "clay" for weighting such as "Tak-a-Note"
or "Uhu Holdit" which are sold in stationery departments.
- Powered flight should only be attempted when satisfied
with the glide. Launch under low power. If indoors, position
yourself to minimize impact with walls. Watch the flight pattern
carefully and make trimming corrections using shims between the
noseblock and the fuselage. Remember, the model should already be
flying well without power.
Gradually increase power and make delicate adjustments until that
magic moment occurs and your plane circles, climbs and cruises just
below the rafters and glides down to a perfect landing.
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Flying Field Etiquette
- Do not talk to a flier who is winding a motor!!! To see a
motor blow as a result of losing count is not a pretty sight.
- After launching indoors, immediately step off the floor so as
not to impede planes or fliers waiting to launch.
- If in doubt, or seeking guidance on building or flying, please
ask for advice. We enjoy our hobby and are eager to help, so don't
be shy. Remember, there are no stupid questions, only stupid
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There are many resources of online info for Free
Flight modelers. We recommend joining the
Free Flight Mailing List. It is an active online community of Free
Flighters from around the world, and a great source of all types of
info. Also, surf some of the sites of the
Free Flight web
ring. Many of them contain
Event and Contest info.
Locally, check in at the neighborhood hobby shop,
and ask for Free Flight contacts. As Free Flight modeling doesn't have
the economic visibility or momentum of radio control, they might not be
able to help, but don't be discouraged. There are likely modelers in
your area that can help. If not, fall back on internet resources for
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Fliers, feel free to link to, or print & circulate
this document, but please do not claim credit for its creation. It was a
lot of work, and a labor of love to help promote the art of model