Of these foam materials, EPP (Expanded Polypropylene) is one of the toughest and most durable foams ever created. Airplanes made of EPP survive collisions with the ground or other objects with little of no damage, and a quick field repair if needed. EPP was developed in the 1970’s for automotive parts. Its first use was to back up plastic bumpers and absorb energy in collisions. EPP can be compressed, then bounce back to its original shape. It is also used in the interior of cars to protect occupants and absorb energy during collisions. Foam model airplanes come in a few varieties of foam including, Depron, Expanded Polystyrene (EPS), and Expanded Polypropylene (EPP). Each type of foam has its advantages and limitations. Depron is thin, light, and smooth, and makes up some of the most advanced indoor models flying today. It is fairly fragile however, and needs frequent repairs. EPS (Expanded Polystyrene) can be molded into complex shapes and has a fairly smooth finish, but it is fragile as well. EPP (Expanded Polypropylene) is flexible and can be compressed, but springs back to its original shape. Its main shortcomings are that it has a rough surface, and it requires some stiffening to hold its shape. Someone sliced a bouncy block of EPP foam into sheets, and began experimenting.

First off, EPP is far more flexible than other foams, so it had to be thicker to give it some rigidity. Carbon fiber rods and strips were added to give more stiffness and to limit twisting. Once these configurations were developed, the EPP airplane took off! Now flat foam airplanes could survive the rigors of 3D maneuvers and frequent contact with obstacles and the ground. I’ve seen these planes maneuvered around and through trees, bushes, concession tables, and inside a garage where the door opener bar was used to land on, loop around, and flop onto again. Even some informal combat seldom requires more that some CA and kicker to return to the fight! EPP makes for very durable planes! Budget RC (BRC) has developed several EPP models including an extensive collection of combat flyers and has video footage showing off the sport well. Short of a propeller chewing away the foam, most mid air collisions result in flying one or both models away, or untangling them after they reach the ground, with little or no damage! BRC also carries an aerobatic “trainer” that is a unique combination of EPP and Depron for maximum durability and lighter weight. At fairly low cost, you can have a fully aerobatic foam airplane that can hit the ground with little or no damage, and is perfect for learning aerobatics and 3D maneuvers. Another product just off the design table is an EPP jet series that hints at unheard of speeds for this flexible material! Records may soon be broken in the realm of high speed profile EPP flight! If you are looking for an airplane that can take some knocks, bounce back for more, and still give excellent flight performance, consider a foam airplane made of EPP!

About the Author

Tom Pepper has been flying planes since about age eight, when he could find five cents for balsa gliders at the local toy store. He got totally geeked about radio control planes when he saw one fly at a Boy Scout Jamboree at age 13. It took until he was 30 years old to have the means and time to build an RC glider (Olympic II) which he learned to fly on. Glow planes followed, and in the last four years he began flying electric planes. Tom has been RC flying for 28 years now. He belongs to the Hudson RC Flyers in Hudson, MI, and has been there for 27 years. His favorite plane to fly plane is “always the one I pull out of the rafters and fire up for the first time of the flying season.” Tom really enjoys electric jets, but lightweight 3D models always offer a thrill a minute too! He has combined his photography hobby with model RC planes and does aerial photography as a part time business. Currently, Tom has four land based planes, one water based plane, and a “Quad” copter that hoists a camera as well. Using video downlink, he can see what the camera is looking at and fire the shots remotely. Tom lives in Jackson, MI with his wife, Anita.

If you are looking for a discussion and some plans, then head over to RCGroups for the Kline Fogleman Airfoiled Flying Wing thread. Perhaps one of the best reads on the KF is by Rich Thompson of Tennessee, or Leadfeather as he is known.  Besides a great thread, Rich has put together a PDF of his research and findings: KF Airfoil Comparison by Rich Thompson.

The stability of the KF Airfoil has led a lot of pilots to use it as a platofrm for aerial photography, such as Aerophilia down in Melbourne, Australia. Using Tony’s BluBaby with a KFm2 airfoil the platform is very steady.  With the KFm2 airfoil the platform is very steady and the video is clear.

I haven’t yet, but here ares some vids of some folks who have:

Combat of the ‘80’s was basically a flying wing with a .40 size nitro motor pulling a plastic streamer.  The thrill was exhilarating and intense.  Several planes in the sky resembled an angry beehive.  Your chances of midair collisions seemed way better than cutting an opponent’s tail.  Wow what a great spectators’ sport.  Most of the planes were cut from foam and when hit sent down a snow shower of styrofoam bits.  Eventually, pilots started making the planes from plastic sign material and PVC gutters.  While these were tough and more durable, performance suffered because of the added weight.  They weren’t as much fun to fly, and I decided to leave the combat arena.

Around the time I left combat flying, RC electrics were being introduced. Slow to start, only a few modelers took the sport seriously.  Although RC electrics continued to grow over the years, they really gained popularity around the turn of the century.  This is in part due to the computer and cell phone industries. Their technologies really put RC electric on the map.  Computers introduced RC to small CD Rom brushless motors, and cell phones allowed for the development of small, powerful and lightweight Lipo batteries. This all gave great performance to the world of RC electric.

RC electrics can be flown almost anywhere space allows, including a park, a golf dome, or even in a gymnasium.  Plus, they’re quiet and easy to operate.  And with all these electric bonuses, I have discovered “Backyard Combat”.  I actually fly in my backyard against anyone willing to take me on.  I use an EPP airframe which averages about a 28” wingspan and a small electric motor which gives me all the performance I need to get away or attack.  The excitement is intense.  The rubber-like EPP takes a direct hit while being extremely light weight.  There’s no more rebuilding entire airplanes; a little CA glue is all you need to make fast repairs.  The power systems are cheap too!  About $60.00 will get you what you need (not including transmitter and receiver).

Although several rules for electric backyard combat are starting to emerge, I like to keep it simple.  I use a 10 ft. streamer of crepe paper cut in half to a 1” width.   A 2” roll can easily be cut   using a band saw to give you 2  1” wide rolls.  If you can find 1” rolls that’s better yet.  I get two colors like white and black.  Cut the black to 5 ft. and cut the white to 5 ft.  Now tape them together to create a 10 ft. streamer.  If an opponent cuts the end color you are considered hit but still in action.  If he cuts the first color you are out.  The battle ends when the first battery dies.  The pilot with the longest tail intact is the winner.

These battles can take place in the backyard, schoolyard, gym, dome, park or flying field.  There are club sponsored events being organized at this time.  With the popularity of electric events growing across the country, I believe RC combat will once again become a popular and profitable venture for several clubs.  Many modelers like the closer action these electrics offer since these battles are usually in a tighter box than nitro combat, and they’re just easier to see.

With great price, durability, and amazing performance, I see electric combat becoming a very large part of the RC world.  Whether it’s in your backyard or a club sponsored event, the fun factor can’t be beat.  Not to mention the fact, NASCAR FANS, that it’s much more exciting than to watch a bunch of cars turning left.  Hah.  In RC combat, we are almost guaranteed the thrill of a collision.  Now that is almost as exciting as a first solo flight!

About The Author

Mark Schoenrock is the owner of Budget RC, designers and manufacturers of RC model airplanes.  His RC experience goes back 31 years with experience in gas and electric models.  His first kit was designed and sold in 1992 called the TRI-FLI.  He lives with his wife Sara and their two sons, Mark and Kyle who are also very busy at Budget RC.  Their home is in the great, small town of Croswell Michigan.

Then too my surprise, I was given an early Christmas present at the December MMAC club meeting.  Bob, our field chairman, found the NJ One and suprised me with it at the meeting.

Bob found the plane after cutting a new acces road for the flying field.  He figured he would look one last time and low and behold he said there it was, upsidedown sitting right on top of some bushes. Bob found the plane about a week before the December MMAC meeting, removed some of the covering and let it dry out a bit. When he found it, it weighed nearly thirteen pounds and was completely water logged. Even with that, the motor still worked and the electronics were good, except for one servo.  The physical damage from the crash was limited to only a broken landing gear. AMAZING.  From the loud cracks I heard that faithful day, I was sure the plane would have been in pieces. Must be the good design.

Thank you Bob! It is great to fly with a bunch of guys who never give up!

That NJ One will be flying again soon. I have removed all the covering, it is drying nicely and the fuse, wings, and tail feathers are all structurally sound.  This time, I am putting a electronic beacon in it – just to be safe.