Aircraft are noisy. Aircraft interiors are by all standards, unacceptably loud. Speech interference levels in even the large wide body jets are too high, as evidenced by difficulty of hearing cabin announcements once a plane is airborne.

The noise spectrum inside an aircraft is high energy and complex with multiple broadband sources arising from interior and exterior origins. Three major sources are (i) engine, fan and propeller noise (ii) airborne noise and (iii) wind (or aerodynamic) noise.1 In all these cases, fuselage wall vibrations act as speakers to launch airborne noise into the cabin. To date, three types of vibration and noise management are employed in the industry. Passive treatments such as insulating layers and constrained layer damping are usually employed throughout an aircraft and are effective only at higher frequencies. Active noise canceling methods are used against low frequency noise. In an active system the vibrations are detected by a sensor, which then sends a signal to a computer. The computer reverses the phase of the signal and sends it to a transducer. The transducer applies a restoring force directly to the source of the noise in the case where the source is a structural vibration to cancel the noise. If the noise is airborne, speakers are used to cancel the noise with "anti-noise" sound. Detailed, expensive three-dimensional sound mapping measurements must be made before an anti-noise speaker system can be designed.

In addition, active systems are both reactive and inefficient since they must cancel all the vibrational energy to be effective. The Company's solution will redirect the vibrational energy flowing through the structure to regions where it can be absorbed or where it is not a problem. The solution will be specific for each aircraft model (as the other passive and active solutions are), will be energy and weight efficient and will be superior to the systems currently in use.
2002 SmartSkin, Inc.
125 Columbia Court, Suite 6
Chaska, MN 55318
phone 952.556.5205
fax 952.556.5206