VITA 48.8 and Air-Flow-Through (AFT) Cooling

Advanced Packaging
VITA 48.8 and Air-Flow-Through (AFT) Cooling

System high power densities achieve reliability with AFT cooling

Curtiss-Wright has extensive analytically and empirically experience in a variety of applications from commercial aerospace to rugged defense with a wide range of product lines. Our card-level products use many forms of cooling including: forced air, conduction, spray cooling, and also liquid-cooled heat frames. At the system level, we have developed solutions that utilize forced air internal, forced air external, forced air via a rugged and compact air conditioning unit, conduction/baseplate cooled, natural convection, liquid-cooled chassis, and Air-Flow-Through (AFT) systems. This extensive experience gives us the ability to understand and perform trade studies of a wide range of solutions to handle the thermal load presented in program requirements.

  • The cooling capacity of up to 200W per 6U VPX slot (or 100W per 3U slot)
  • Environmentally sealed to accommodate the harshest environments
  • Ideal for high power, high-performance applications such as sensor processing
  • Does not require exotic materials or fluids associated with liquid or evaporative cooling
  • Highest reliability among active cooling solutions
  • VITA 48.5 for 6U and 48.8 for 3U standards
Air Flow Through (AFT) Chassis
For systems requiring high power densities, AFT cooling is one of the most reliable active cooling solutions. By providing a thermal path of the least possible resistance, AFT cooled chassis from Curtiss-Wright can handle thermal densities up to 200W per system slot.
Air Flow Through card showing the heat frame

AFT technology passes air through the heat frame, preventing the ambient air from contacting the electronics, but decreasing the thermal path to the cooling air dramatically.

On both the inlet and the exhaust sides of the card, a gasket mounted inside the chassis seals the card’s internal air passage to the chassis side walls. These seals prevent air from being blown into the chassis and protect the internal electronics from the harsh external environment.



With component power, overall module power, and heat density continuing to increase, Curtiss-Wright is leading the way in rugged, 3U VPX Air-Flow-Through technology with a 3U AFT chassis. By providing a thermal path of the least possible resistance, a 3U AFT cooled chassis from Curtiss-Wright can handle thermal loads up to 100W per system slot.

Benefits of AFT Cooling

6U VPX AFT Processor Module

The AFT approach brings the cooling air in very close proximity to the high power components. This applies to both the components on the base card and to the components on mezzanine cards. Providing a short circuit path to the cooling ambient air from the high power components on a mezzanine card will allow the highest performance possible. Each high power component interfaces to the AFT heat frame through a conductive, flexible gap pad.

Every card has an isolated thermal path using AFT. Instead of cards having to share cooling air or share the thermal interface into which they conduct heat, each AFT card has its own inlet and its own exhaust. There is no other cooling path other than the cooling air, which allows every card to be viewed in isolation from a thermal standpoint. The critical aspect at the system level is to ensure balanced airflow through all of the cards, so that each card has the required amount of cooling air to keep components at their appropriate temperature.

Given the benefits of AFT in simplicity of design, weight efficiency and low thermal resistance, AFT cooling technology is ideal for high power applications such as sensor processing.

Example AFT Chassis
3U VPX AFT System
6U VPX AFT System 3U VPX AFT System

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Cooling Techniques

Fluid-Flow-Through Cooling  
Fluid-Flow-Through Cooling

FFT cooling uses fixed channels (air-cooled or liquid-cooled) built into the chassis to cool the electronics

Liquid-Flow-Through Cooling

LFT cooling uses a liquid-cooled system to cool cards from 200-1000W

Conduction Cooling  
Conduction Cooling

Ideal for lower density (50W) computing applications that require ruggedization

Convection Cooling  
Convection Cooling

Transfer of heat from electronics into the ambient air using airflow