What Is a Foamie RC Plane?

guest post by Tony Treat

Electric power and foam RC planes make an ideal match

Model airplane construction in general, and radio control models in particular, have made several evolutions over the years. The first rubber-powered free-flight model planes flown in the early 1900s were made from bamboo yet turned in some surprisingly good flight times.

Lightweight balsa wood quickly became the model airplane building material of choice. Today, with the rapid introduction of micro-sized RC gear, powerful electric motors and lightweight rechargeable batteries, foam RC planes are an increasingly popular building material.

Using foam to construct RC planes has several advantages. Foam is inexpensive and incredibly lightweight. Foam is typically not as sturdy as a typical balsa wood model airplane structure. Balsa has the advantage of coming in different densities (strength) and can use the stronger wood grains in areas requiring greater strength.

Buying Tips

If you are in a hurry, you can choose one of the planes listed below. You can’t go wrong with any of them; just pick a model and go have some fun. We did all the research to make sure they are great choices for beginners.

However, if you want to dig deeper and find that great foam RC plane for beginners by yourself, here are some useful tips:

  • Make sure the plane is indeed for beginners and is easy to fly. There are some new technologies, that help beginners avoid crashes such as SAFE or gyro self-stabilization systems.
  • The foam should be lightweight and durable.
  • You should be able to find replacement parts easily.
  • The plane should have a beginner mode.
  • Ready to fly kits will help you start flying in seconds.

Best Foam RC Planes for Beginners

Glues and Foam – How to Repair Your Foam RC Plane

You need to select with care the glues that you employ to bond foam parts. Foam safe cyanoacrylate (CA) glue usually works well, as does epoxy glue and hot glue guns. As each type of foam can have slightly different characteristics, be sure to test any glue on a scrap piece of material before using it on your foam RC plane.

As with testing glue for a foam model, you will need to do the same for paints and other coverings. Foam can melt with the typical temperatures used to apply heat shrink plastic coverings. These heat-activated coverings can be applied in certain low-temperature cases. Check the manufacturer’s recommendations and test on a sample of the foam.

The same caveats go for any type of paint on foam. Test first on a piece of scrap material before working on your final foam RC plane. Some paints attack the foam, literally melting whatever foam surface the paint is applied on.

The good news is there are several paint products that do not damage foam, yet adhere well. As a general rule, acrylic paints work well with most foam products. Also, any type of paint that can be cleaned with water should be a suitable match for your foam RC aircraft.

One final point on paint, glue, and coverings for a foam plane and this regards fuel proofing. A huge advantage of electric-powered models involves the fact that you do not need to fuel proof your airplane. This is especially relevant for foam models, where the foam building material itself may be vulnerable from the effect of fuel used for a gas-powered aircraft.

Check that whatever paint you employ for a foam model is waterproof. It would be a disappointment to not consider this aspect of your model’s finish, and notice a ruined paint scheme from exposure to a small amount of moisture.

As a side note, the foam was never a largely successful building material for gas-powered model aircraft, as it is generally not resistant to the effects of engine fuel and exhaust residue. Foam usually could not provide a robust enough structure for the flight loads and stresses employed for these types of mid-size to large radio control aircraft.

Foam RC Planes – Building Tips

Foam is an ideal building material for electric powered RC models

Foam is has been in existence for several decades. Only recently has foam found widespread use for building lightweight radio control model airplanes.

Since the dawn of practical RC flight in the mid 1960s, all models were powered by gas engines for outdoor flight. Balsa and various other hardwoods were used to make just about every airplane built, as these construction materials had adequate strength for the engine vibration and stress loads of these larger aircraft.

Foam and electric RC models

The challenges of using foam on fuel-powered aircraft vanish when used for electric-powered models. With the smaller size of a typical indoor RC plane powered with today’s powerful electric motors, the use of foam as a construction material quickly becomes an ideal choice.

The flight loads on these smaller foam RC planes are far less than their heavier fuel-powered brethren. Foam for these indoor flyers can be very thin and molded into complex curved shapes. And if additional strength or reinforcement is required, this can be quickly added by the use of lightweight carbon rods and strips glued into place.

There are a wide variety of foam types to choose from as you build your RC model plane. Depron is a popular thin insulation foam that can be formed for curves shapes in smaller RC models. EPP foam is a flexible variant, used for many ready to fly indoor RC aircraft. Foam board and Blucor Fanfold foam is a solid foam and is used for slightly heavier electric powered RC aircraft.

The key advantage of foam model planes is that the foam is inexpensive and allows for rapidly building model aircraft prototypes. There is little downside to making an experimental aircraft to determine flight characteristics. It is even feasible to employ a simple profile plane design and make several versions with different types of foam.

As always, seek a light aircraft flight weight, ensure a proper center of gravity location, and use carbon rods or strips as needed to reinforce weaker sections of your foam radio control model plane. Foam, employed properly, is a great addition to your RC model aircraft design and building techniques.

Foam for non-structural aircraft parts

Foam was used for non-structural sections of numerous RC model aircraft, such as a turtle deck, fuel drop tanks, or portions of a nose cowl. Foam is lightweight and easily shaped, making it a very suitable material for these sorts of modeling tasks. But it was the lack of structural strength that made building a foam RC plane a difficult goal to achieve.

This concept for RC aircraft design changed with the advent of micro radio control systems for model flight. Starting around 2005 or so extremely lightweight electronics, rechargeable lipo batteries and powerful tiny electric motors for the first time allowed for practical micro RC flight.

This changed everything for the RC hobbyist. One could now fly year round in colder climates. The low cost of these control systems combined with numerous ready to fly airplanes and helicopters, caused RC model plane designers everywhere to rethink old assumptions about building foam RC planes.

For starters the existing limitation of the low strength of foam could now be addressed. Lightweight RC models produce very little stress on the airframe. These models usually fly slowly so that any crash or hard landing has a minimal chance of damaging the airframe. For the first time foam can be widely used as a primary construction material for radio control models.

Foam can be reinforced

It now became an easy matter when building foam RC planes to include some reinforcement to prevent wing flexing or add fuselage strength. Carbon rods, strips and tape can be glued on the foam surface of a model aircraft, or cut into channels in the wing. Carbon rods provide very effective bracing and reinforcement of thin foam wings for indoor flyers, just as wire bracing was used to strengthen World War I aircraft. This bracing concept can be used for model monoplanes as well as smaller biplanes such as the 4-Site.

If carbon reinforcement is not available, wooden dowels or strips of plywood work well as substitutes. This concept of combining a lightweight material (foam) with a reinforcement material such as plywood can be applied to all your lightweight model building tasks. Note my use of 1/16 inch plywood to reinforce the balsa wing dowels in the Blackburn and the Chickadee.

The use of electric power precludes the need for any type of fuel proofing for a foam model plane. You do not need to cover or even paint a foam RC model.

An inherent advantage of building foam model planes is the fact that you can design and build an airplane very quickly.

Foam is ideal for rapid prototype model construction to test different model design concepts. Foam allows a modeler to try various wing sizes and placement, tail layouts and nose moments to achieve your desired flight performance. Once the design is finalized, you can then prepare a final set of construction plans and make the final version.

Experiment with different types of foam

There are different types of foam used for model airplane construction. The best way ahead is to see what others have accomplished with the various types of foam either at your local flying site or on one of the internet forums.

Foam is inexpensive enough that you can obtain samples and test them on your own. Depron is a popular thin and lightweight foam used on smaller models. EPP is a flexible foam used in many ready to fly models. Foam used as insulation for building construction is available at home improvement stores, and comes in brand names as Blucor Fanfold, or a generic name with pink foam board.

In summary, foam has always had potential as an inexpensive, easy to work material for building foam RC planes. The need for structural strength required by larger gas-powered aircraft precluded the widespread use of foam.

This has all changed now with the widespread use of small flying model aircraft. Foam is the ideal construction material for these aircraft due to their light finished weight and low flight loads. The ability to selectively reinforce foam structures with carbon or wood allows for even more innovative use of foam as a foundation-building method for today’s micro RC model aircraft.

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