Abstract: An automatic speed control system for a power trowel for regulated adjustment of rotational speed of the trowel rotor assemblies. The disclosure provides for and is configurable to automatically regulate trowel speed and can be adapted to utilize advanced control features like cruise control and power management. The disclosed system incorporates several user and feedback inputs in a number of logic patterns for trowel control.

Abstract: An ultrasonic inspection reference standard for composite materials having porosity may include a member, having at least one thickness and defined by a plurality of holes, that is manufactured from a fiber-free polymer resin. The ultrasonic inspection reference standard may have similar acoustic properties to prior art, porous, fiber-reinforced, composite reference standards, at lower manufacturing cost. A photo-polymer resin reference standard, having at least one thickness and defined by a plurality of holes, may be created using a stereo lithography process. The polymer resin reference standard may replace more costly porous, fiber-reinforced, composite reference standards. The ultrasonic inspection reference standard, manufactured from a polymer resin, may be used for ultrasonic inspection of porous, fiber-reinforced composite parts in the aircraft industry and in other non-aircraft applications.

Abstract: The invention relates to tapered reference standards, and methods for their manufacture and use. An ultrasonic inspection reference standard for tapered, composite materials may include a member having at least one tapered section. The member may be manufactured from a fiber-free polymer resin using a stereo lithography process. The tapered reference standards may substantially mimic the affect on ultrasonic sound passing through tapered sections in composite laminates.

Abstract: The invention relates to pseudo porosity standards, and methods for their manufacture and use, which may substantially mimic the effect porosity has on ultrasonic sound as it passes through a composite laminate. An ultrasonic inspection reference standard for composite materials having porosity may include a member having at least one thickness and at least one discrete wire. The member may be manufactured from a fiber-free polymer resin using a stereo lithography process. The discrete wire may scatter and attenuate ultrasonic energy. The reference standard may replace more costly, porous, fiber-reinforced, composite reference standards in the aircraft industry and in other non-aircraft applications.

Abstract: An ultrasonic inspection reference standard for composite materials having porosity may include a member, having at least one thickness and defined by a plurality of holes, that is manufactured from a fiber-free polymer resin. The ultrasonic inspection reference standard may have similar acoustic properties to prior art, porous, fiber-reinforced, composite reference standards, at lower manufacturing cost. A photo-polymer resin reference standard, having at least one thickness and defined by a plurality of holes, may be created using a stereo lithography process. The polymer resin reference standard may replace more costly porous, fiber-reinforced, composite reference standards. The ultrasonic inspection reference standard, manufactured from a polymer resin, may be used for ultrasonic inspection of porous, fiber-reinforced composite parts in the aircraft industry and in other non-aircraft applications.

Abstract: An ultrasonic inspection reference standard for composite materials includes a rectangular prism that is manufactured from a polymer resin. The ultrasonic inspection reference standard may be a polymer resin step-wedge reference standard that has similar acoustic properties as prior art fiber-reinforced composite step-wedge reference standards at significantly lower manufacturing cost. A photo-polymer resin reference standard may be created using a stereo lithography process. The polymer resin reference standard may replace a currently used expensive fiber-reinforced composite reference standard. The ultrasonic inspection reference standard manufactured from a polymer resin may be used, for example, for ultrasonic inspection of fiber-reinforced composite parts. The polymer resin reference standard may be used, for example, in the aircraft airframe industry, both commercial and defense.