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.
As predicted last week, testing the window with full pressure and cold temperature has blown up the test box with no damage to the window.
The test box was filled with offcuts of blue foam and sealed up. More blue foam was placed on top to hold the dry ice. The dry ice surface temperature was -100F and it froze the window surface down to -70F. Then we pressurised it to above the fuselage design pressure and held that pressure for 30 minutes.
Then we increased the pressure until the box exploded. Watch the 30-second video above.
We pressurised a test window for the first time today. We ran it up to the full design pressure although we did not test the (higher) proof pressure. There were no leaks and no problems with the window.
I expect we will find that the window is unbreakable. The test box will almost certainly fail before the window does.
Jim Murray and Pat McLaughlin have been working on phase 2 of the project for several months now. We have only just gotten around to adding them to the “team” page on the web site.
Patrick is the owner of Mountain High, which makes the best oxygen systems available for regular gliders. He has been working on the cabin pressurisation system for the Perlan.
Jim has been working with Jeff Bozanic (who will be added to the team page soon) on the rebreather system.
The rebreather oxygen system has been tested in a simple form. Jim Murray has put together a re-configurable system using simple plumbing parts. This allows us to test different configurations to work out which is best.
The tests were very encouraging. The CO2 scrubber lasted much longer than predicted and the heat and moisture build-up were much less than predicted.
Now we know what configuration works best, we will continue testing the rebreather in cold and altitude conditions.
The first plug was given its first coat of epoxy today. The glistening covering makes it look like a beached whale, complete with dorsal fin and even a blowhole, thanks to the single remaining alignment hole.
The epoxy will cure overnight and then we can do more sanding.
I have gained a new title on the project: Master of Imperfections. It’s my job to insert some little stuff-ups into the fabrication of the window test unit.
The first fuselage plug is now all bonded (glued) together. The first two blocks of foam were levelled to within a hundredth of an inch – less than the thickness of a piece of paper. This makes a perfectly flat foundation for the other blocks. This is also the centreline of the fuselage so getting this line straight is necessary so that the other parts of the aircraft will fit and it will fly straight.
The other blocks were then aligned onto the first pair, using alignment rods and careful measuring before the epoxy resin was poured.