Other Construction Materials for Model-Building

I am a traditionalist.  I do not like plastic or foam so I generally do not use them in the models I design unless I am feeling particularly lazy or want to get a prototype in the air quickly.

In spite of my own attitude regarding these materials, they are good when used properly.

Many materials can be found in useful sizes in a variety of places.  Often you can find materials for free.  It comes under the category of "one man's trash is another man's future flying masterpiece."

Materials

• ABS Plastic

  ABS Plastic is used to vacuum-form difficult to shape parts such as cowlings, wheel pants and surface details such as cowl bumps, engine exhausts, etc.  I feel these parts are much inferior to fiberglass as plastic tends to crack from engine vibration and many paints will peel off the plastic after a while.

  Paints that will not peel off the plastic can melt the plastic unless it is sprayed on in light coats.  Most modelers attempt to spray on one thick coat of paint even though every set of instructions they've ever read said do not do that.  This can result in the plastic crazing under the paint.  What that means is the solvent in the paint reacted with the plastic in a bad way.

• Beaded Polystyrene Foam

  Hot-wire cut Foam Plastic has been used since at least the 60's to make wing cores.  The core is cut from a block of beaded polystyrene foam (not Styrofoam) using a thin, hot wire (nichrome).  The core is then sheeted with balsa, veneer plywood or a synthetic material.

  Built up wings that are fully sheeted are difficult to make smooth and often the sheeting sags between the ribs unless the builder is skilled and careful.  Foam cores virtually eliminate this problem.  Unfortunately, foam wings tend to be heavy unless the builder goes to great lengths to prevent weight build up.  Usually this means cutting sections from the foam so it resembles lattice-work.

  Hot wire cut foam has become popular for many other items besides wings.  Entire aircraft are sometimes built from it.  Usually it is used to cut the turtleback on ARF models, but tools are now available that allow any modeler to cut wings, fuselages and other shapes easily.

• Butyrate Plastic

  Generally used to vacuum form canopies.

• Carbon Fiber

  A newer material that has become very popular.  It is a relatively expensive material.  However, it is becoming more widely available which means it should come down in price.  It has a very high strength to weight ratio and is used to make propellers, landing gears and various reinforcement throughout the model.

  Carbon Fiber is not difficult to work with, but the splinters can be really nasty.  You have to be careful to break your habit of running your hand along the edge of a part after sanding it to feel how smooth it is.

• CoroPlast

  A plastic material made like corrugated cardboard.  It has two outer layers and a corrugated inner layer.  This is another material I have not used, but it has become popular with manufacturers of "indestructible" aircraft.

  CoroPlast is a heavy material so that indestructibleness comes at the price of forever having a heavy model.  Apparently it is easy to work with.

• Corrugated Cardboard

  This is another material I have never used because it has a lot of disadvantages both in building the model and it is flight worthiness.  It is only advantage is that it is widely available and it is inexpensive.  It generally does not build into pretty models, is heavy and has a poor strength to weight ratio.

  Oops!  I stand corrected.  Charles Felton has built many very attractive cardboard R/C models.  Visit his site for information and tips about building with this inexpensive and easily obtained material.

  • Chuck's Cardboard Model Aircraft

• Fiberglass

  I like fiberglass because it is lightweight, long lasting and the parts can be made thin enough to replicate features on scale aircraft such as aircraft cowlings.  Wood equivalents generally need to be too thick for scale.

  Plastic parts can be used in these cases, but I consider plastic to be inferior to fiberglass.  Fiberglass is lighter, stronger and lasts longer than plastic.

• FoamCor

  FoamCor was popular for a while for R/C planes, but has since faded out.  I am not sure why it did not stick around, but I expect that it did not tend to build into models that were as light as expected.  FoamCor's only advantage over other materials is its lower cost.

• Injection molded foam

  Manufacturers use molded foam for lightweight models that do not require any type of sheeting to strengthen it.  Normally these are small models that are electric powered.  For higher performance models, there is often a carbon fiber or wood spar molded into the wing.

• Styrene Plastic

  Available in sheets from hobby shops and is often used for scale details in cockpits.  It is not used for general construction due to its weight and tendency to crack.

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Copyright © 2002 Paul K. Johnson