`Is it an Airplane or a Bird?` Spy-Plane Getting Smaller and Smaller..

At somewhere in the demilitarized zone in 2010, a palm-sized miniature plane sends detailed photographs of North Korean solders’ movement crossing the zone frequently. This craft is so tiny that even a radar cannot catch it. It is indistinguishable from a bird or an insect.

Sound like science fiction? It is a scenario of the future intelligence war. A Micro Air Vehicle (MAV) is expected to be a must-carry-item for solders or secret agents who are in charge of spying security facility, combat, or suppressing a terror.

To tell the truth, in December, 1999, a research team at ADD in Korea tried an experimental flight of a tiny aircraft whose weight was 95g and size was 20 cm for which a miniature plane’s engine and remote control system were used. Yet, the plane flied for just about 10 seconds and the research was stopped.

For this time, Korea Institute of Science and Technology (KIST), the big brother among the government contributed institutes, has launched into the project. They have begun a full-scale 5 year project to make a Micro Air Vehicle with a budget of 1.2 billion won. A good new has been heard within 2 years. KIST MAV project team took 2nd place at the International MAV Competition which was held on 7th April, in Florida, U.S..

The craft which weighs of 130g, a cell-phone weight, and is 22 cm long takes pictures of buildings and streets. It sends them following the pilot’s remote command flying in the sky above KIST which is located at Hongneung in Seoul. Its maximum flying time is 6 minutes.

In this craft, a 25g, CMOS camera has been installed which was developed by the project team. They put the smallest engine for a remote controlled miniature plane which was imported. However, to make a smaller engine than that, the team is currently developing a 5mm-sized micro gas turbine.

The project team aimed to make a MAV whose size and weight would be 100g and 15 cm in next 10 years. It can send pictures while flying in a space wider than the radius of 3 km for more than 30 minutes.

Dr. Kim Sung-Il, the chief engineer at the team, said, ``The most difficult part of the project is to make a self-controllable chip.`` This chip is to contain Inertial Navigation System (INS), Global Positioning System (GPS), an aero compass, a speed meter, and a distance meter so that the application of Microelectromechanical (MEMS) technology is necessary.

Professor John Ahn at Sejong University, a young prospect from MIT, is developing a MAV which will be 15 cm long and weighs 35g. He said, ``It is advantageous if the craft’ wing is wider and it flies slowly because a totally different aerodynamics principal is applied for a tiny aircraft.`` In fact, his aircraft has a unusually big wing. It is also known that if the size of craft becomes smaller than a palm, a form of an insect’ wing is more effective than that of a bird.

It was the time of the Gulf War when the first MAV introduced in an actual situation. American military sent a tiny unmanned spy-plane whose size was about 1.5m. Based on that success, since 1997, U.S. Defense Advanced Research Projects Agency (DARPA) has been contributing 35 million dollars of research fund for developing a 15 cm-sized MAV to MIT and CALTEC.

AeroVIronment, INC, a leading American company in the field successfully finished in 1998 an experimental flight of `The Black Widow`, a MAV which is 15 cm long, for 17 minutes. This company and CALTEC are also developing a bat-shape aircraft. U.C. Berkeley also is trying to make a 1 cm-sized `Smart Fly` that flaps its wing like an insect.

Research teams are studying the principal of migratory birds and insects’ flight. Because a migratory bird can fly 3.000 km without stopping consuming just 3~4g of its internal fat.

dongho@donga.com