Earlier development of Balloon and Airship

[Ran Exilis]

Nice anecdote there

The Romans did have silk, imported from China - in fact Roman officials worried that Rome's coffers were being emptied as rich Romans bought up silk and trade was only flowing in one direction.

They did not know the secret of its origin, though, so getting enough to make balloons would have been difficult (unless they do find out in TTL).

Which reminds me; IIRC, the OTL Byzantines learnt the secret of silk production during the 6th century.

 

[AirshipArmada]

From
http://www.nott.com/Pages/projects.php
Where some folks made balloons using inca tech (referred to up-thred).

Thick wood-smoke flows from a fire via a trench and pours into Condor I. It cures the fabric, filling its pores. "To our surprise," says Nott, "the quality of the smoke was crucial. Modern historians assume all that mattered was the heat and laugh at the Montgolfiers for believing what they burned was important. But this balloon showed the Montgolfiers were right: the nature of the smoke it critical."

and

And while I do not see any evidence that the Nazca civilization did fly, it is beyond any doubt that they could have. And so could the ancient Egyptians, the Romans, the Vikings, any civilization. With just a loom and fire you can fly! This raises intriguing questions about the development of science . . .

So - some experimenter figures smoke rises and if he can trap it in a bag then he might be able to fly. He makes a big linen bag and traps a lot of smoke, the bag fills but doesn't provide enough lift. He tries again with different smoke. This time he is lucky and uses a wood which produces the right type of smoke to seal the pores. Lift off!

But balloons are still far from airships. They would still be very useful. Here is a naval siege "tower" I mocked up over lunch break.