Abstract: In a step-bending die device, the die has a horizontal surface and an inclined surface, forming a semicircular groove with a semicircular cross section along a longitudinal direction on the horizontal surface and installing a semicircular rotary blade rotatably in the semicircular groove. The punch has a horizontal surface and an inclined surface, forming a semicircular groove with a semicircular cross section in a longitudinal direction on the horizontal surface and installing a semicircular rotary blade rotatably in the semicircular groove. Vertical notches at positions changing from the horizontal surfaces to the inclined surfaces are formed in longitudinal directions in the die and the punch so that top portions of the die and the punch are formed. The punch is assembled so that the horizontal surface of the punch faces the inclined surface of the die, and the inclined surface of the punch faces the horizontal surface of the die.

Abstract: An optical system for detecting ice and water on the surface of an aircraft includes an elongated transparent optical element having first and second end portions. A light source and light detector are disposed in one end of the optical element and a reflective surface is disposed in the opposite end portion. The reflective surface defines a critical angle and reflects light from the light source to the light detector when the critical angle is in contact with air and refracts the light toward the external environment when the reflective surface is in contact with ice or water. The system may also incorporate an optical element wherein the reflective surface includes a continuous array of convex elements extending outwardly from and across one end of the optical element and wherein each of the convex elements defines a critical angle.

Abstract: An optical system for detecting ice and water on the surface of an aircraft includes an elongated transparent optical element having first and second end portions. A light source and light detector are disposed in one end of the optical element and a reflective surface is disposed in the opposite end portion. The reflective surface defines a critical angle and reflects light from the light source to the light detector when the critical angle is in contact with air and refracts the light toward the external environment when the reflective surface is in contact with ice or water. The system may also incorporate an optical element wherein the reflective surface includes a continuous array of convex elements extending outwardly from and across one end of the optical element and wherein each of the convex elements defines a critical angle.

Abstract: An optical system for detecting ice and water on the surface of an aircraft includes an elongated transparent optical element having first and second end portions. A light source and light detector are disposed in one end of the optical element and a reflective surface is disposed in the opposite end portion. The reflective surface defines a critical angle and reflects light from the light source to the light detector when the critical angle is in contact with air and refracts the light toward the external environment when the reflective surface is in contact with ice or water. The system may also incorporate an optical element wherein the reflective surface includes a continuous array of convex elements extending outwardly from and across one end of the optical element and wherein each of the convex elements defines a critical angle.

Abstract: A helicopter of the type having an electrical system, a landing light, a master switch and a power supply of between about 18-32 V for operating the electrical system when the master switch is in an on position also includes a landing light fault detector. The landing light fault detector includes a light switch for turning the landing lights on and off and circuit means for detecting a fault in the landing light and for providing a signal indicative of a fault whether or not the light switch is in an on or off position.