Managing thermals in Army helicopter cockpits

Posted by John McHale
Managing thermals in avionics is a big challenge in the OH-58F Kiowa Warrior upgrade, says Lt. Col. Scott Rauer, product manager, Kiowa Warrior Program Executive Office at Redstone Arsenal, Ala. Unlike the Apache helicopter, which has a dedicated cooling system, "my two main boxes are clustered together where they are open to ambient air and operating in hot environments."

Rauer made his comments to me during interviews for an article I was writing on helicopter avionics. For more on that interview read "Army looks to helicopter avionics upgrades and technology insertion in the absence of new rotorcraft programs."

"The new smaller boxes are better at thermal management and we've also noticed a trend toward more thermally efficient electronics at the board and chip level," Rauer says.

It can take quite a bit of problem solving as these aircraft are operatign in very hot environments with limited space in the cockpit, Rauer says. In one case "we are designing a box where the exhaust from one box blows to the intake of another box -- to help keep it cool. It's delicate jigsaw puzzle."

Engineers at Rockwell Collins in Cedar Rapids, Iowa, say creative thinking is necessary as the new processors are generating so much more heat. For one program Rockwell Collins helped manage the thermals on a display system by taking advantage of light emitting diode (LED) power efficiencies for the backlighting, which helped reduce the overall temperature of the system, says Dan Toy, principal marketing manager in mobility and rotary wing business area at Rockwell Collins.

Investing in filters, compensators, and unique optics can help minimize the power draw from a lighting source, Toy adds. "We are constantly making sure we have the appropriate solution."

Even though processors are getting power hungry you can do a lot more in single processor than ever before, says Steve Edwards, chief technology officer for Curtiss-Wright Controls Embedded Computing in Leesburg, Va. "If we can cool a module, you may have less power at the platform level."

Some vendors will allow users to change clock speeds to reduce power on Intel chips, Edwards continues. If the application does not need to do full-up processing, the clock speed adjustment will enable them to throttle back and reduce power voltage on the chip, he adds.

Curtiss-Wright Controls Electronic Systems in Littleton, Mass., has a new technology line called CoolWall that is available in a 3U form factor and ideal for applications such as helicopter avionics or unmanned aerial vehicles, Edwards says. This technology is based on a proprietary mixture of metal composite materials, and provides the ability to thermally manage high-power payloads in multiprocessing and digital signal processing (DSP) applications.

It came from Curtiss-Wright's acquisition of rugged enclosure and chassis designer Hybricon, he adds.