A critical upgrade for 2018 was to build a new front hatch. The original clearly worked to 54,000 feet, thanks to Keith Kongslie's work in 2016. But it was not a perfect match between hatch and fuselage. Jim and Greg decided perfection was the goal. And on May 4 (Star Wars Day - May the fourth ...be with you) perfection was accomplished. Greg Scates and Mike Malis have worked on the front hatch project for months. Both are retired from Lockheed Martin and have decades of composite experience between them.
Perlan 2 was inverted so they could more easily work building the exact match to the fuselage curvature. Once that tool was built then a hatch ring with 16 layers was layed up, squeezed out and slow cooked. Then the new clear polycarbonate was bonded into the ring. Polycarbonate is very strong when cold, but scratches very easily. That's why there is a removable film protecting the transperancy. If you look closely you can see the almost finished hatch nestled exactly in the tool. Both are black carbon fiber, so it is a bit difficult to see.
Purposely the ring was made larger than our final requirement in order to make vacuum bagging easier and to produce a stronger result. It cured in the heated "oven" until strong. That meant trimming and fine tuning once it was brought to Minden for the final fit test. We were very pleased when we pressure tested the new hatch on the Perlan 2 in the hangar. We had the slowest leak rate ever measured for Perlan 2 with this new front hatch with a very simple silicone gasket. There is a short 50 second video on our YouTube channel showing these steps and the pressure testing https://youtu.be/8o79lkjEoys
Now it is almost time for some flight testing! Jackie