Materials for Indoor Planes

2mm Wallpaper Insulation Foam

2mm wallpaper insulation foam comes on a 10m roll for about £3. The advantage of this material is that it is very quick and cheap to use so it's ideal for experimenting with and trying out ideas. It has a bright white colour which is an excellent base for painting with acrylic paints (which also helps hide the rather course cell structure). One of the nice things about using this material is that wings are very quick to make since they are formed from a flat plate cut from the roll and then curved to an aerofoil section - you don't have to make lots of ribs (great for triplanes!). As a result, it is possible to do all the paint effects on a flat sheet before cutting out the parts. If you make a mistake, throw it away and do another one - you haven't made a mess of a comples structure you've spent hours building. Once you've finished painting, cut out the parts and stick them together - the Flitzer shown only takes about an hour altogether to assemble the main structure. The material can be creased and rolled to make compound curves, but you have to keep an eye open for poor quality cell structure on some rolls which tends to crack if you bend it too much. Rounded fuselages are made from tube and cone components or rolled up kipper shapes. Once glued together it forms a surprisingly strong stressed skin construction. For larger models such as the remote controlled ones, the wing can be made from two sheets with a foam or balsa spar in between. Bulkheads for larger models can be formed in a similar way with two sheets and 2mm foam spacers in between.

Depron Foam

Depron foam comes in sheets of various thicknesses from 0.5mm to about 4mm. It is a much denser foam than the wallpaper foam with a shiny smooth surface. Generally, it can only be curved slightly without creasing, although it is possible to mould it a little with heat. It can not be manipulated into tight curves and compound curves in the same way as the wallpaper foam. For aeroplanes with simple box section fuselages it is a quick way of making a strong structure with a good smooth finish. It is also very useful for structural components such as spars in bigger foam wings and can be used flat for tail surfaces. For single surface wings it can be held in an aerofoil section by glueing Depron ribs to the underside of the wing. The thicker stuff is good for making bulkheads and formers.

Blue Foam

For the ultimate in surface finish for scale models, blue foam block can be used. This involves carving and cutting the very fine grain foam into solid shapes such as the fuselage, wings etc. The fuselage can then be cut in half and hollowed out until just a thin shell is left. You have to be prepared to get it really thin - the experts go as thin as 0.5mm - and put up with lots of static-charged dust. The result is a very strong yet light monocoque construction wth a very smooth surface as good as a plastic kit. There is now also a similar white foam block available which is more suited to aircraft with bright colour schemes which are easier to achieve on the white surface. For larger models the wing may also be cut into two halves and hollowed out. David Deadman's book shows step by step drawings illustrating the process of creating an aeroplane from solid blue foam.

Painting

We use acrylic paints which don't smell and can be thinned with water. Local toy shops often have them as do some DIY stores. Get a good quality brush as it makes a huge difference especially if trying to paint effects such as wing ribs. Alternatively you can use an airbrush. Remember that paint is heavy!

Glue

Bison contact glue is the one we use. It grabs quickly which is useful when making fuselages from rolled up foam. There are other makes which are similar, you may have to try several to get one that is a true contact glue. Many glues which say they will; glue polystyrene are in fact PVA (white) glue, which will work but takes a long time to dry.

Indoor Quality Balsa

Indoor quality balsa is completely different from the big stuff you might be used to. It comes in very thin sheets which are ideal for making thin propeller blades. Even though it is so thin, it is specially selected so it's much stronger than just sanding down a thicker bit of 'normal' balsa.

Yoghurt Pots

Don't throw them away. The plastic makes very good thin propeller blades for rubber power and the smaller electric motors. Peach and Apricot is my favourite...Hold an existing propeller against the side of the pot to get the right angle from the vertical and when you cut out the blade it will have a nice twist on it. These blades are very tough so are a good alternative to balsa propeller blades.

Plastic Beads

Go to your local toy shop and see if they have children's jewellery kits. They often have little bags of glass or plastic beads which make good thrust bearings for rubber powered propellers.

Acetate Sheet

Get these from your copying shop. There are various thicknesses, generally the stuff used for doing cover sheets for reports is thicker than the overhead projector sheets. Use it for moulding canopies over a gas or electric fire. More details are in the datasheet on making canopies. Buy several sheets because you're bound to melt a few holes in them - I always do!