Sailplanes and Gliders

Gliders are planes that do not typically have any type of propulsion, as a general rule. Because most gliders are unpowered, flight must be sustained through exploitation of the natural lift produced from thermals or wind hitting a slope. Dynamic soaring is another popular way of providing energy to gliders that is becoming more and more common.

Jets

Jets tend to be very expensive and commonly use a micro turbine or ducted fan to power them. Most airframes are constructed from fiber glass and carbon fiber. Inside the aircraft, wooden spars reinforce the body to make a rigid airframe . They also have kevlar fuel tanks for the Jet A fuel that they run on. Most micro turbines start with propane, burn for a few seconds before introducing the jet fuel by solenoid. These aircraft can often reach speeds in excess of 320 km/h (200 mph). They require incredibly quick reflexes and very expensive equipment, so are usually reserved for the expert. The FAA heavily regulates flying of such aircraft to only approved AMA (Academy of Model Aeronautics) sites, in where certified turbine pilots may fly. Also, the AMA requires model aviation enthusiasts who wish to operate miniature gas turbine powered RC model aircraft, to be certified in the operation of the type of gas turbine engine, and all aspects of safety in operating such a turbine-powered model aircraft, that they need to know in flying their model.[1]. Some military bases allow such high tech aircraft to fly within limited airspace such as Kaneohe Marine base in Hawaii, and Whidbey Island NAS in Washington State. An average turbine aircraft will cost between $150–$10,000 with more than $20,000 all-up becoming more common. Many manufactures sell airframes such as Yellow Aircraft and Skymaster. Turbines are produced from The Netherlands (AMT)to Mexico (Artes Jets). The average microturbine will cost between $2500 and $5000 depending on engine output. Smaller turbines put out about 12 lbf (53 N) of thrust, while larger microturbines can put out as much as 45 lbf (200 N) of thrust. Radio control jets require an on board FADEC (Full Authority Digital Engine Control) controller, this controls the turbine, just like a larger turbine. RC Jets also require electrical power. Most have a LIPO (Lithium Polymer pack) at 8-12 volts that control the FADEC. There is also a LIPO for the onboard servos that control ailerons, elevator, rudder, flaps and landing gear.

Pylon racers

     Racers are small propeller aircraft that race around a 2, 3, or 4 pylon track. They tend to be hard to see and can often go over 240 km/h (150 mph), though some people do pylon races with much slower aircraft. Although several different types of aircraft are raced across the world, those flown primarily in the US are; Q500 (424 or ARPRA, and 428), and Q40. 424 is designed as a starting point into the world of pylon racing. Inexpensive (under $200 for the airframe) kits with wing areas of 3,200 square centimetres (500 sq in) are flown with .40 size engines that can be purchased for less than $100. The goal is for the planes to be not only inexpensive, but closely matched in performance. This places the emphasis on good piloting. APRA is a version of 424 with specific rules designed for consistency. 428 aircraft are similar to 424 in appearance. The difference is in engine performance and construction. The planes are primarily made of fiberglass with composites used at high load points. Wings are often hollow to save weight. (All aircraft must meet a minimum weight. A lighter wing moves more of the weight closer to the center of gravity. This requires less control deflection and its resulting drag to change the planes attitude.) They also use .40 cu in size engines but unlike 424 they are much more expensive. They have been designed to put out the maximum amount of power at a specific RPM using a specific fuel. Nelson manufactures the most predominantly used engine. Speeds are very fast in this class with planes capable of reaching 290 km/h (180 mph). Q40 is the highpoint of pylon racing, as their aircraft resemble full size race planes. They are not limited to the simple shapes that Q500 planes are, which have much cleaner aerodynamics and less wing area. They use the same basic Nelson engine used in 428, but the engine is tuned to turn a much smaller prop at a much higher rpm. The planes accelerate much more slowly than 428, but their clean airframes allow them to reach higher speeds, and maintain them around the turns. These planes can fly in excess of 320 km/h (200 mph) on the course. Because of their limited wing area however, Q40 planes must fly a larger arc around the pylons to conserve energy. Although faster, they ultimately fly a larger course. Ironically the best times for a 10 lap 3 pylon Q40 race are very close to the same in 428.

Helicopters

Radio-controlled helicopters, although often grouped with RC aircraft, are in a class of their own because of the vast differences in construction, aerodynamics and flight training. Hobbyists will often venture from planes, to jets and to helicopters as they enjoy the challenges, excitement and satisfaction of flying. Some radio-controlled helicopters have photo or video cameras installed and are used for aerial imaging or surveillance. Newer "3d" radio control helicopters can fly inverted with the advent of advanced swash heads, and servo linkage that enables the pilot to immediately reverse the pitch of the blades, creating a reverse in thrust.

Flying bird models, or ornithopters

Some RC models take their inspiration from nature. These may be gliders made to look like a real bird, but more often they actually fly by flapping wings. Spectators are often surprised to see that such a model can really fly. These factors as well as the added building challenge add to the enjoyment of flying bird models, though some ARF (almost-ready-to-fly) models are available. Flapping-wing models are also known as ornithopters, the technical name for an aircraft whose driving airfoils oscillate instead of rotate.