Print this articlePrint this article


Written by Alpha Enos, Director of Global Products and Development, Motion RC
A foam, electric PNP from start to finish
Feature
As seen in the July 2019 issue of Model Aviation.


This is a wonderful time to be an RC modeler! As fellow hobbyists, we at Motion RC are as passionate about building, flying, and enjoying RC aircraft as you are. Strengthened by the support of our amazing global customer family these past seven years, we are grateful for the continued opportunity to move our beloved hobby forward.

Our team is especially passionate about leading the development, distribution, and support of RC airplanes that you know and love. You might have seen several of our products reviewed in Model Aviation and wondered what goes into creating them.

customer feedback directly informs motion rc planning sessions
01. Customer feedback directly informs Motion RC’s planning sessions.

Spanning a multiyear, multinational development process, we’ve summarized the journey a foam electric RC airplane travels from our hands to your hangars. You might find that these methods are generally applicable to the process of any RC foam manufacturer, but with our personal touch. Let’s begin!

Planning

The creative process begins with the planning phase. Customer feedback, comparative analysis, and market factors are all key considerations that influence our decision on which new model aircraft to create.

We’ve developed more than 50 aircraft throughout the years, and each new model fits a specific place in our portfolio that further articulates our vision for the RC foam market, which is to maximize convenience, quality, innovation, safety, diversity, and customer choice.

At any given time, the Motion RC development team is working on several models at different stages throughout this process in order to sustain the frequent stream of new products we are known for across a spectrum of sizes and price points.

After a subject aircraft is selected, its size, target cost, and target market are set. We also use online forums, such as HobbySquawk.com, as direct points of interaction with our customer family to gauge potential interest.

The team balances making popular models such as Corsairs and Cubs with less-common subjects like Crusaders, MiGs, and Ta-152s, because we all have our wish list of favorites!

Drafting and Prototyping

With planning complete, we create three-dimensional models from scratch using 3D CAD modeling software. Various references are used to hone the model’s exterior, including laser scanning and photogrammetric technology, to transfer physical shapes to electronic models, which can then be scaled and manipulated by our team of drafters.

If available, we also access the full-scale aircraft for "hands on" reference gathering. Modeling scale fidelity presents unique challenges in foam RC, but we believe that every reasonable effort should be made to represent the full-scale aircraft with integrity. To us, these models embody history enlivened.

The exterior of an aircraft is only one aspect of the 3D drafting phase. The most important elements we focus on involve the layout of various electronics and structural components that will enable the aircraft to fly, and the aerodynamic optimizations that will ensure that it flies well.

Computer simulations help us assess the efficacy of proposed airfoils, proportions, material thicknesses, battery position, and general construction of major components. We also draw upon previous models in our database, leveraging lessons and customer feedback as to which characteristics they prefer. Whether designing a warbird or EDF jet, extra attention is spent on balancing undercarriage loads.

Ideal wing loading is also crucial, so each subassembly is designed in harmony with the others to balance the final model aircraft’s landing speed, weight, transportability, structural integrity, and component cost. After a complete aircraft is drafted, we proceed to the prototyping phase, where the flying begins!

every 3d model is created from scratch by company engineers
02. Every 3D model is created from scratch by company engineers.

a 5-ton cnc machine mills a fuselage mold
03. A 5-ton CNC machine mills a fuselage mold throughout the course of several days.

a molding machine stands more than 9 feet tall
04. A molding machine stands more than 9 feet tall.

the same molding machine opens to allow a worker
05. The same molding machine opens to allow a worker to access the inside in between the injection cycles.

after assembly this freewing a-10
06. After assembly, this Freewing A-10’s internal wing structure will be encased in foam.

Because of the exceedingly high cost of the final production molds, during the prototyping stage, we fly prototypes that are CNC milled from solid foam. This enables our team to fly the prototype aircraft and make cost-effective adjustments as needed to test different wings or parts before investing in the final molds.

Prototypes are flown a minimum of 200 times throughout several months to satisfy the hundreds of safety and performance criteria that our test program requires. Proprietary tools and methods are applied to optimize the aircraft aerodynamically to achieve its desired flight behavior. Trainers are designed to have a gentle stall, advanced aircraft are tuned to provide high performance with reasonable flight times, and aircraft intended to attract a general audience are balanced with a range of pilot-friendly characteristics.

After the prototype’s aesthetic and aerodynamic elements are finalized, the mold design team converts the prototype’s files to create the actual molds. This labor-intensive conversion can take two to four months and involves scientific methods to visualize how the molds will perform during both the injection and assembly phases.

The major parts themselves are divided into substructures, which are assembled like a puzzle. It is the mold designer’s challenge to fit those puzzle pieces into a mold without sacrificing mold performance. A 90 mm EDF jet’s fuselage might include 20 interlocking foam structures, so their constituent shapes are different from what a pilot will observe from the outside on the finished product.

Innovations within this mold design phase have contributed to the smooth surface quality seen on many modern foam RC aircraft.

A common misconception about "foam planes" is that they are made entirely of foam. In fact, one of our typical midsize aircraft will utilize parts composed of materials, including foam, fiberglass, carbon fiber, plastic, fiber-reinforced plastic, high-density polyethylene, plywood, brass, nylon, steel, and aluminum.

As an example, the wing of Motion RC’s Freewing 80mm A-10 Thunderbolt alone is composed of five interlocking foam parts and three plastic parts all requiring molds, seven laser-cut plywood parts, a CNC-machined aluminum bracer, four carbon-fiber parts, LEDs, a circuit board, and associated hardware, including nylon, brass, and steel components.

Even the foam shell that encases the model’s parts inside the shipping box is meticulously designed to be compact, yet secure. A finished model such as the Freewing A-10 contains more than 800 parts. Coupled with an extensive supply chain and material/tooling costs, the development costs of a humble RC model aircraft of this type surpass six figures!

Mold Making

The molds are milled or "carved" from solid steel by giant CNC machines, then workers finish the molds with hand polishing and rigging. The process of milling the molds alone requires hundreds of hours. Larger fuselage and wing molds can weigh several hundred pounds and are transported using forklifts. Even smaller plastic molds require a heavy-duty gantry to move them into the injection machines.

some aircraft include more than 50 hand-applied decals
07. Some aircraft include more than 50 hand-applied decals.

an employee uses a copper paint mask while he sprays an l-39 fuselage
08. An employee uses a copper paint mask while he sprays an L-39 fuselage. Specialized materials and techniques ensure durable paint adhesion.

ISO 9001 quality-management standards are maintained at all of our partner factories to ensure quality, and the Motion RC team personally inspects each factory at regular intervals. Molds constitute such a large investment in our company’s future because a mold can last many years when properly maintained. After they are completed, the set of molds is transported to our factories to begin their work.

The foam molds are composed of two halves which are designed to fit together. Liquid foam is injected at a predetermined temperature and pressure into the cavities between the two mold halves. After a set time, the mold halves are hydraulically separated, and a worker enters the machine to remove each part by hand before preparing the mold to cycle again. Similar to a recipe, the ingredients are tested until the perfect combination is found.

Each aircraft’s constituent puzzle pieces are different, so the techniques behind designing molds that perform well with optimal surface smoothness, flow, and consistency for a given volume is a carefully applied science. Most modern foam airplanes use EPO foam, which is more dense and "oily" than EPS foam, which is lighter but less resistant to damage.

There are also different grades of EPO foam, each with different properties. Sometimes a single aircraft will use two or even three grades of foam. For example, our Freewing A-10 uses heavier, but stronger, foam for its wing roots, and lighter foam for its fuselage, where flight loads are comparatively lower.

Production

With the molds completed and tested, the final production phase can begin. First, production teams are trained to produce the new aircraft, with direct input from the engineering team to ensure every detail is reviewed carefully. Materials are ordered from a series of suppliers, initial production testing begins, and flight testing continues.

This process can take several months before Motion RC gives the final green light to begin serial production, which will mass-produce the final model aircraft that our customers around the world will receive.

Serial production begins with preparing the molded-foam and molded-plastic parts, painting all of the external parts, then constructing, installing, and testing the electronics, including servos, ESCs, motors, electric retracts, and LED lighting.

Independent quality-control teams scrutinize each stage, with specialists in electronics, molding, painting chemistry, and packaging. To protect the foam surface, every workstation is padded, and each time a foam part is moved to the next station, it is rewrapped in foam and transited on a foam-padded rolling shelf.

the f-16 canopies are inspected before packing
09. The F-16 canopies are inspected before packing.

Workstations are regularly rewrapped in fresh foam to keep them clean. More than 100 people will touch an aircraft through the production process before it reaches a customer, so protective measures are important. At any point in the production line, damaged parts are identified and scrapped.

Painting a foam, electric model is an art form unto itself and requires creating copper paint molds or masks, which conform to the surface of the foam model to block paint from adhering to unwanted areas. Each reusable copper mask is created by machine and finished by hand, and even includes every panel line to prevent overspray.

The 1 mm wide panel lines are hammered into the copper to create a raised relief. Artisans who specialize in this technique are rare, and we keep them busy! In certain examples, such as the Freewing Me 262, mottling camouflage is airbrushed by hand. Special paint that is formulated for foam is used to strengthen adhesion and aid in wear resistance.

At the primary assembly factory, different teams focus on various aspects of production. There are 24 teams, including painters, those who place decals, testers, and packagers. In a given month, these teams will produce varying quantities of roughly 20 different aircraft models to satisfy our orders.

Because of the handcrafted nature of creating foam RC aircraft, training and retaining an experienced workforce is an important facet of establishing a consistent product. We’re proud of our entire team, each of whom works hard and pours his or her talents into creating your aircraft!

From Our Hangar to Yours

After our initial order for an aircraft and its spare parts are mass produced, it is packaged and shipped to the appropriate distribution center in the US or Europe, where it awaits its final destination: your home. Meanwhile, the Motion RC marketing team generates exciting content, our technical support teams go to work delivering world-class support of our newest creation, and our development team continues with the next prototype in our product pipeline.

The journey of a foam RC model aircraft from its inception to its first safe landing at your local flying field is a long one. It is the culmination of nearly two years of planning, development, and production. Most importantly, we believe it is just the beginning because more vital than the creation of an RC aircraft is our support of it.

This RC hobby is greater than all of us, and we each have a special role to play in its proliferation. If our team’s creative process has piqued your interest, we hope it inspires you to share this hobby with a friend.

As for Motion RC, our work continues in support of all fliers everywhere!

how foam aircraft are made

SOURCES:

Motion RC

(224) 633-9090

www.motionrc.com

Add new comment