Hints and Tips
Choice of subject
For the beginner to free flight scale modelling, the decision as to which
aircraft type to
model can have the biggest effect on whether the project is a success or not.
tricky subject (from the construction or flying point of view) and you could be
put off for life.
I would also recommend not building a scale model until you have built and
flown one or two sport
models, to learn the basics of building, covering and trimming - these tend to
be more forgiving
than scale jobs.
An ideal first subject would be a high wing monoplane with flat fuselage
sides, and a minimum of
stringers. The high wing gives maximum stability, and the simple structure
makes building simpler,
and keeps the weight down. Perhaps not as glamourous as a WW2 fighter, but hey
- we can
work up to that later - let's get a successful model or two under our belt
There are lots to kits choose from, but beware - the wood selection in some is not
ideal (often too heavy),
and many serious modellers replace much of the stripwood (and even sheet) with
from their own stocks. Some kit propellers are also not the best design to
achieve maximum duration
from the rubber motor (too little blade area is common). Against this, all
the parts you need are there
in the one box, and you don't have to worry about transfering former shapes
etc. onto balsa sheet.
Plenty of choice amongst available kits - a couple of suggestions from the
ranges I have experience of (thinking
rubber powered, outdoor, somewhere in the 20 to 30" span region) would
Airsail (a New Zealand firm) produce a very nice 28" Pilatus Turbo Porter, and
20" Auster AOP 9 - both
with die-cut parts.
West Wings in the UK have an excellent 24" span D.H.Puss Moth in their range,
which flies well.
Aerographics (another UK firm) produce an Auster J4 kit and this has been joined recently by a 20" span Lacey M-10,
which as well as being a nice simple shape, is an extremely good flier.
Hacker Models produce three very complete kits that would be ideal first
is a Piper Cub, D.H.C.Beaver and Champion Citabria. All parts are cut out and
ready laminated balsa
outlines are even provided for the wingtips. All three are designed primarily
for CO2 power (the
Gasparin GM 120 being the recommended power source), but they are easily
converted to rubber power.
This should not be thought of as a definitive list by any means - there are
plenty of other fine flying
kit models out there - these are just one or two suggestions.
I was brought up with the Keil Kraft and Veron Flying scale ranges, some of
which can be made to fly very
if built carefully, and the dreadful propellors replaced. They always were
rather heavy though, unless
you changed the wood, which was usually of the "heart of oak" variety. Most
of my childhood
efforts managed nothing more than a brief hop, but the aeromodelling bug bit,
and I haven't been able
to stop since! Experienced modellers might like to have a go at the Veron
Tiger Moth and Sopwith Triplane
sometime - they both are great fliers. One pair of wings is probably quite
enough to be worrying about though
if you are new to the hobby!
One or two thoughts:
Cover your plan with clear plastic film to stop the glue sticking to it (e.g.
slit open a plastic bag)
When building a fuselage frame, build one over the plan, then cover with
plastic film, and
build the second half directly over the first - that way they come out exactly
the same shape and size
Use a sharp knife, and when making a cut, stick to that old adage, "measure
twice, cut once"
Use glue sparingly - it is a lot heavier than the balsa.
When joining the fuselage halves together, to keep them at 90 degrees to the
building board, use
something like a set square or block with right angle corners on the outside of
One thing that works well is to use those
plastic floppy disc boxes that you get when you buy 10. If they are full of
discs, the weight
of the box is often sufficient to hold the fuselage frame in position.
If you are building a plane with fuselage stringers, scallop out the formers
between each stringer after assembly. This
prevents them showing through the tissue, and also saves weight.
If your model has a parallel chord wing, so all the wing ribs are the same, I
tend to cut a master
rib from ply or plastic card, then use this as a template to cut a pile of
identical ones from balsa.
Concentrate your weight saving efforts on the rear of the aircraft, especially
for a rubber powered plane
- if you can make the back
really light, this will minimise the amount of noseweight you have to add to
balance the model.
Half a gram at the back can save 1.5 grams at the front!
After tissue covering the model you will want to water shrink the tissue. Old
Eau de Toilette sprays are very suitable for this task, allowing a fine water
mist to be applied.
Don't forget to hold wings, tailplanes and fins flat while the tissue dries,
otherwise warps can occur.
My method (if you can call it that) involves placing the edges of table mats
under the leading and
trailing edges, leaving a gap underneath the wet part, and balancing small
spice jars around the
edge of the part to keep it weighted down (high tech, eh?)
When dope is applied to the tissue, make sure it is well thinned (at least
50/50 with cellulose
thinners). If you add a couple of drops of castor oil to the jar and mix it
in, this acts as
a plasticiser, and helps to prevent warps. As with water shrinking - hold your
parts flat while
the dope dries.
When you first come to take the brave step of throwing your newly completed
masterpiece at the
scenery, it is very unlikely to glide along beautifully straight away - some
going to be needed! Before you start adjusting anything, make sure the centre
(balance point) is close to the point shown on the plan. Having it too far
forwards is less of
a problem than having it too far rearwards (a forward c of g actually helps
Probably the most common way of allowing for adjustment on the tailplane is
to fit it in a slot
through the fuselage that is wider than the thickness of the tailplane. It can
be held in place with
balsa or ply shims. These can be moved around during test flights to either
elevate the rear of the tailplane to correct
the model diving, or elevate the front of the tailplane to correct a stall.
Another method of allowing for adjustment is to make the elevators and
rudder as separate parts
and attach them to the tailplane and fin using hinges simply made from soft
wire. This does add a little weight
but looks neater, and makes adjustments simpler. Once the correct positions
have been determined,
a drop of superglue (cyanoacrylate) will lock everything in place. My own
experience with this method
is that it works great for small models such as peanut scale models (13" span),
but can be a bit
sensitive on larger models. The large size of the elevators can mean that a
very small adjustment makes
a big difference to the trim of the model. What I have now started doing is
adding movable trim tabs to
the tailplane, fin and even the wings of low wing models. I try to put these
in a similar position
to those on the full size plane, but make them rather larger. These make fine
adjustments to the trim
easier to make. The wing trim tabs are useful for helping to keep the outside
wing of an aircraft
down in a turn - for example, imagine a plane circling left - you do not want
the left wing to dip,
so you bend the trim tab on the right wing up. This has two effects - firstly
it reduces the average
lift on the right wing, and secondly (perhaps more importantly) increases the
drag on the right wing.
Both these factors should help prevent the left wing from dropping. On high
wing (more stable)
models, these tabs are rarely necessary.
Once low powered flights are looking OK, and longer flights are attempted,
it may be found necessary
to start adjusting the thrustline of the prop. A common reason is the
appearance of "power stalling"
- the model stalls under high power, though not on the glide. Most models seem
to need a at least a little down and right
thrust, so I usually build some in. On a rubber model this simply means
glueing in the nose bush at an
angle - stick a long bit of wire through it so you can see the angle relative
to the fuselage. Later adjustment
is traditionally by shimming behind the nose block with thin ply, though
adjustable bearings are now commercially
available. On models using a power unit other than
rubber (eg. CO2, Electric or Diesel) it is a case of angling the mounting
bulkhead or bearers, or just
shimming with washers. In is important to be able to easily get at such power
units "in the field" to be able to adjust
thrust angles if necessary - do not bury the motor inside the model with only a
small access hatch, and remember
you will need to get at both sides of any screw fixings. On small models,
access panels tend to stay in
place with just friction, but you have scope to be ingenious with hooks, rubber
bands, dowels or even press-studs!
Other random tips
One simple way to transfer printed patterns for formers, ribs etc. from a plan
onto balsa sheet is to
photocopy the relevant bits off the plan, cut them out and paste them onto a
sheet of paper
the same shape as the piece of wood you are going to use. You can stack
everything as tight as
you like to save precious balsa! Once satisfied, photocopy the result. Next
take your new copy
, place it face down on the balsa, and iron the parts onto the wood with a
medium hot iron.
The heat melts the toner and prints it on the wood. It is quite probable that
the wood will
curl up slightly - a quick iron on the back of the wood should bring it back.
I tend to
leave the wood to settle down for a couple of weeks afterwards before using
Another possibility is to again place the photocopy face down on the wood, then
thinners onto the rear of the paper using a wad of kitchen towel.
Yet another possibility is to simply stick your final photocopy face up onto
the wood using a spray
photo mount adhesive, such as produced by 3M. You then have to cut through the
paper and the wood
together when cutting the parts out, but this actually helps to reduce
splitting of the balsa.
The paper is peeled off afterwards.
Simple black markings for a scale model can be produced on a normal photocopier
by simply copying
artwork onto clear decal sheet, as sold for plastic modelling. I did the small
titles and logos
on my Corben Super Ace like this, copying the artwork off the plan. If you
need a white background,
simply copy onto white decal sheet instead of clear.
A neat way of retaining a wheel on a wire axle is to cut a thin slice from a
piece of aluminium
tubing of suitable diameter, slip this over the end of the axle, and either
apply a drop of cyano
to the end, of simply crimp on with pliers.
Looking for a windshield for your latest model? - keep a look out next time you
are in a supermarket -
it is amazing what shapes you can find amongst the transparent packaging used
I tend to hoard such material - if nothing else, it provides an endless supply
of material to have a go
stretch formed canopy moulding (and I usually need plenty of attempts before I
get get one good
When using a commercial plastic prop for a rubber model, check that it is
balanced before fitting.
Chances are that one blade will be slightly heavier than the other - the heavy
blade will always stop at
the bottom when you spin it on a piece of wire. Sandpaper the heavy blade
using wet and dry emery
paper until the prop comes to rest in a random position after spinning. A
balanced prop will give a