ER-2 Doppler Radar - Data System Electronics Enclosure

Time period

May 2001 to June 2001

Project description

The Electronics Enclosure was designed and built for a Doppler Radar instrument that is housed in the nose of the NASA ER-2 high altitude research aircraft. The system had a previous design for an enclosure to hold its data processing electronics. The old design was difficult to install, did not provide an adequate thermal environment for the electronics, and was not asthettically pleasing.

The old design had an outer skin that was bolted to hard points in the nose of the ER-2. The electronics were then slid into and bolted to the outer skin. The new design shown is built around a standard off the shelf card rack (shown in orange in the middle of the enclosure). The main body of the enclosure is 19.9 inches (50.5 centimeters) wide x 11.9 inches (30.2 centimeters) tall x 12.25 inches (31.1centimeters) deep to approximately match the existing enclosure. The mounting "ears" on the side increase the overall width to 23.9 inches and these attach the enclosure to the mounting points in the ER-2 nose. This design allows all of the electronics to remain enclosed and gives easy access to the mounting points.

The previous design continuously pulled very cold air into the box from the outside environment. This was done in anticipation that the electronics would need to be cooled and if they needed to be heated, approximately 100W of heat could be added to the incoming air through heaters. However, it was learned that the electronics were being cooled below freezing even with the extra heating. This was not a problem during operation since there is little moisture at the operating altitude above 60,000 feet.

However, as the aircraft descended, the cold electronics would allow water to condense. This could cause electrical short circuits. The new design seals the internal electronics from the outside air. The internal air is very well circulated in order to cool hot spots and heat cold spots using convection. The new design should keep the electronics warm enough to eliminate the previous condensation problems.

The customers for this project are pleased with the appearance of the new design. Therefore, the asthetic requirements have been met.

Challenges and lessons learned

This project was my first large scale test for eliminating conventional 2Dimension shop drawings for fabrication. All of the machining is performed using just the 3D computer models for generation of the CNC code. This speeds the product development process and reduces costs.