Long-haul truck seats could enhance helo ride

 - July 7, 2010, 6:59 AM

New Bose technology designed to dampen the road vibration translated into semi-truck cab seats could be applied to helicopters, according to at least one leading aircraft seating engineer.

Earlier this year, Bose unveiled its Ride System for long-haul trucks. The company said the three-part system is the culmination of 25 years of research. It features a suspension base and an integrated, custom-designed seat top. Vibration is mitigated via a high-power, linear electromagnetic actuator capable of counteracting road forces. A compact, bidirectional power amplifier delivers 3,500 Watts to the actuator but draws less power than a 50-Watt light bulb. Sensors and proprietary control algorithms are used to counteract road forces before they reach the driver. Bose tested the system on 77 drivers over the course of a month and 84 percent reported improved comfort, while 66 percent said they were less fatigued. Bose said the estimated cost of the system is “well under $10,000” per unit.

The debilitating impact of constant, in-flight vibration on the human body’s muscle and skeletal systems and internal organs, as well as on alertness, has long been a concern of the aeromedical community. In 2005, the U.S. Navy commissioned a study on whole-body vibration that compared the vibration loads generated by standard polyfoam Sikorsky MH-60S crew seat cushions to those made of visco-elastic or “memory” foam from Oregon Aero. Use of the latter was found to reduce vibration frequency in all axes, but particularly the “Z”–or lateral–axis, where it dropped by 40 percent. However, the study noted that these reduced levels were still substantially above “recommended action levels” for vibration set by the EU. Getting those vibration levels lower would undoubtedly require new seat cushions and some sort of active vibration-canceling system in the aircraft seat structure, the entire airframe or both.

When asked if Bose was working to apply the Ride System to aircraft, a company spokesman would say only that Bose “does not discuss future product plans.” However, Kevin Walsh, a senior aircraft seating engineer who has worked for several leading OEMs, said the technology has potential application for aircraft, including helicopters. “The concept is there. The question is whether the parts are small enough to fit into the package–the seat pan structure– and if it would stay attached once you ran the seat down the [dynamic] test sled,” he said. All new helicopter seats must pass a 30g crash test. Walsh also said that the weight of the system is a potential consideration. “It’s doable,” he said. “There is no reason why it shouldn’t work.”