Archive for August, 2009

The second test box has now been completed. This box is intended to test the hatch with pressure and cold.

This is a process of iterative design and testing. The first test box showed that the fixed-window design is adequate but the box itself failed. This new one has much more carbon fibre layup in the area that failed. It actually has less carbon in the main body of the box – if we can make the plane lighter, we will do so.
The test hatch has been constructed in exactly the way that we expect to make the flight article. We have refined our technique for forming the Makrolon (polycarbonate) into the window shape. The window has been bonded into the hatch in the same way as the sucessful fixed window. Once again, we have two identical panes of Makrolon, each of which is capable of holding the full test pressure on its own.

The hatch has passed the initial test – it does hold pressure. In fact the result was better than we could have hoped for – there was no measurable leak after 2 hours.

Next week we expect to test the hatch at full proof-test pressure and 100 degrees below zero. I’m not really sure what to expect – the box should hold a higer pressure than the previous burst pressure but we don’t want to burst this one right away before doing more long-term tests.

The rebreather system development is continuing. We have sucessfully tested some more refinements to the design. Jeff Bozanic has been invaluable, contributing expertise and identifying some diving hardware which will be useful to us.

The “breadboard” rig has been updated to include an exercise bike. This was used to increase oxygen consmption and CO₂ production. The work-rate of the exercise was so much higer than the expected work rate that this option will not appear in the next version.

The results were very promising, confirming that this is the correct direction to move forwards with more development.

The fuselage plugs have been painted in their final coat of paint. There is still a lot more sanding and surface preparation before we can start construction of the mold.