Does the model reproduce ships that actually flew?
Does it hold up?
Every rigid airship with published figures, modelled from its own envelope and compared. Where the model misses, the discrepancy is recorded rather than tuned away.
Does it hold up against ships that actually flew?
Unit tests catch regressions. These catch being wrong. The model is fed published geometry for every rigid airship in the reference set and has to reproduce published gross lift within a stated tolerance. Where a source contradicts itself, the fixture records the contradiction rather than resolving it quietly.
| Ship | Gas | Volume | Model | Published | Error | Gate |
|---|---|---|---|---|---|---|
| LZ-129 Hindenburg1936 | hydrogen | 200,000 m³ | 227.9 t | 232.0 t | -1.75% | PASS |
| USS Macon (ZRS-5)1933 | helium | 184,059 m³ | 184.6 t | 182.8 t | +0.99% | PASS |
| USS Akron (ZRS-4)1931 | helium | 184,059 m³ | 184.6 t | 182.8 t | +0.99% | PASS |
| LZ-127 Graf Zeppelin1928 | hydrogen | 75,000 m³ | 85.5 t | — | — | n/a |
Gas purity is first-order, not a refinement
The US Navy quoted Akron and Macon at 95 percent fill with “helium of standard purity”, which was itself about 95 percent, because helium was expensive and the Navy cared about the lift it actually had. Modelled with pure helium, the ship fails its own gate by more than twice the tolerance.
Air leaks inward through the cell film continuously, and lost purity is lost lift, permanently, unless the gas is replaced. On a vehicle whose premise is never landing, the only way to replace it is to make more. That is why onboard electrolysis is load-bearing rather than clever.