Envelope – cutting day

We have a big weekend behind us! The actual plan for and the structure of the envelope blueprints was:

Airship Envelope:
- Total length: 6500mm
- Front section: Half-torus, forming an intake funnel, 1500mm long, radius 1000mm
- Central section: Cylinder, 2000mm long, radius 1000mm
- Rear section: Half-ellipsoid, 3000mm long, radius 1000mm
Material Sheets:
- Width: 1000mm (folded in the middle for handling and easier alignment when welding)
- Circumference calculation based on radial distances
Objective:
- Calculate radial distances and corresponding circumferences for points along the airship’s length.
- Divide the circumference by the closest number of material sheets, then by 2 (because of folding).
- Transfer these calculations into a cutting plan on material sheets.

To be able to cut the envelope in sheets it actually needed to be separated in multiple logical pieces where front section’s been split into the rotational half-ellipse(2) with an intake cutout (1).

Sheet shape calculation Excel spreadsheet then looks like this, getting some nice graphs:

Y-values from a spreadsheet are then providing widths of the half-folded sheet for every 10cm of its length. So the plan is to do 7 sheets alongside the envelope.

This image then shows single cutting sheet of 7, where all being identical:

There is also a wedge piece which serves to isolate the inner tube from envelope and also to support the envelope lift tensions across its length. On a spreadsheet above you can see it as Y (for) wedge.

Well the D-day came Saturday when whole team arrived to Vilda’s work in Beenleigh and long story short it took us nearly 10 hrs to translate that spreadsheet to reality – let pictures to talk.