Development of an Attitude Sensor for a Cm-Sized Helicopter

Our developed cm-sized helicopter is inclined with a large pitch angle by the nose down moment generated by the aft propeller when it goes forward and when it keeps its position against a wind. This is because the ratio of parasite drag to the gravitational force is larger for a smaller helicopter. And the horizontal component of aerodynamic force generated by the main rotors, which equals the parasite drag, should be larger. Then, a small and lightweight attitude sensor was newly developed to measure the large pitching angle of the helicopter and to control the rotational speed of the aft propeller. The principle is same as that of a solar sensor.