There are several categories of aircraft which qualify as ultralights in some countries: •
Fixed-wing aircraft: traditional
airplane-style designs. •
Weight-shift control trike: use a hang glider-style wing, below which is suspended a three-wheeled carriage which carries the engine and aviators. These aircraft are controlled by pushing against a horizontal control bar in roughly the same way as a hang glider pilot flies. •
Powered parachute: fuselage-mounted engines with parafoil wings, which are wheeled aircraft. •
Powered paraglider: backpack engines with parafoil wings, which are foot-launched. •
Powered hang glider: motorized foot-launched hang glider harness. •
Autogyro: rotary wing with fuselage-mounted engine, a gyrocopter is different from a helicopter in that the rotating wing is not powered, the engine provides forward thrust and the airflow through the rotary blades causes them to
autorotate or "spin up" thereby creating lift. •
Helicopter: there are a number of single-seat and two-place helicopters which fall under the microlight categories in countries such as New Zealand. However, few helicopter designs fall within the more restrictive ultralight category defined in the United States of America. •
Hot air balloon: there are numerous ultralight hot air balloons in the US, and several more have been built and flown in France and Australia in recent years. Some ultralight hot air balloons are
hopper balloons, while others are regular hot air balloons that carry passengers in a basket.
Electric Advancements in batteries, motors, and motor controllers has led to some practical production
electric propulsion systems for some ultralight applications. In many ways, ultralights are a good application for electric power as some models are capable of flying with low power, which allows longer duration flights on battery power. In 2007, the first pioneering company in this field, the
Electric Aircraft Corporation, began offering engine kits to convert ultralight weight shift trikes to electric power. The 18
hp motor weighs and an efficiency of 90% is claimed by designer Randall Fishman. The battery consists of a lithium-polymer battery pack of 5.6 kWh which provides 1.5 hours of flying in the trike application. The company claimed a flight recharge cost of 60 cents in 2007. A significant obstacle to the adoption of electric propulsion for ultralights in the U.S. is the weight of the battery, which is considered part of the empty weight of the aircraft despite efforts to have it considered as fuel. As the
specific energy of batteries improves, lighter batteries can be used. ==See also==