Yes, the original hatches worked for Perlan 2 to 54,000 feet. But the team wanted perfect hatches made to exactly fit the contour of the fuselage openings. The best description of the hatch shape is a Pringle's potato chip. 3-D curvature - both compound and complex. Once the new front hatch was proved a success (see http://perlanproject.org/blog/perlan-2-perfect-pressurization-test ), Greg Scates started on the new rear hatch.
Greg (composites expert) made a splash from the rear cockpit opening. Then he created a tool using that precise curvature. Mike Malis (aviation and composites engineer) had run the numbers to calculate how many plies of carbon fiber were required for the desired strength. Mike and Greg worked together when possible. The outer ring was cured in the oven, just like the front hatch.
Then it was time to place the outer transparency (window) into the ring. More calculations. Jim Payne was able to join this step of cutting 5 layers of quarter circle arcs out of carbon fiber. Greg put them all in place and cured the outer ring again. Finally an inner ring was made to hold the inner transparency. Like most homes have dual paned windows to conserve heat, so does Perlan 2.
Tim was able to pick up Greg and Mike's second hatch masterpiece and bring it to Minden. Kelly Rosser will use the special paint (pearlesent of course since Perlan means pearl in Scandanavian.) Perlan Project is named after the extremely high altitude clouds which shimmer pearlesent.
For a 1:30 minute video click on https://youtu.be/G7W7VzSgxDU
Perlan Soars High! Jackie