Re: TL5 Dirigible based on Spaceships help wanted
 

Seasoning wood takes a stupidly long time. You could just let it get warm and evaporate the water in a much shorter timespan (I've done this personally with wet wood while camping; just put it near the fire for awhile and it'll dry out enough that you can use it). It would probably take a good deal of time with green wood, and you'd probably get really crappy (for purposes of making stuff) wood out of it, so just stick with charcoal.

Alright then, no charge. If you really think they'd be specially (and expensively) designed for rapid transit, I'd charge $1M for the whole thing ($250K/system).

I've heard it can be used to clear hangovers and/or the effects of certain recreational drugs, so some of the sailors might find a use for it in that regard (particularly if they tend to experiment with discovered plants and the like). As a result of this reputation, captains and/or expedition party leaders might keep an oxygen tank on hand so they can breathe it to "clear their minds" when they feel the need. It might also be thought that breathing it will allow one to recover more readily from fatigue, and thus be carried (and breathed every so often) on long marches.
Hey, nobody said it had to truly be useful, just so long as there is a perceived use. Of course, you can also opt to let it work as the characters think - giving positive TDM's on IQ-based checks and increasing FP regeneration (or decreasing its expenditure). Fortunately, it won't really be pure oxygen at TL5 (impurities, notably water, will likely get in the mix), so it shouldn't dry out the lungs too much.

I've got no clue, and I don't know any metallurgists sadly. All you're really doing, however, is burning things hotter, which should probably actually give you better efficiencies, rather than worse (efficiency gets better as the difference in temperature between source and sink increases). Off-hand, I'd say you might be able to get away with 1.5x power with ~1.4x fuel expenditure with a lot of oxygen - maybe a full gasbag's worth burned over the course of merely an hour!

These numbers, like yours, are pretty much from thin air. Maybe someone else will come along who has a better idea?

That is awesome. Did TL5 have mountainbike equivalents? You're going to need some rugged tires, unless you're intending to use the bikes only at civilized stops.

You might be able to downgrade some of the bits and use something like this to escort the various bicycle expeditions as support.

Re: TL5 Dirigible based on Spaceships help wanted
 

That quadracycle is awesome. But alas as a first generation gas engine it's definitely TL6. An even weirder one powered by compressed air would be possible if inefficient and clunky. Perfect for an overfunded gadget loving expedition type endeavor.

I imagine making a one speed mountain bike wouldn't be that much more difficult than a multi-speed one. Also, solid rubber tires would be hardier and easier to make.

As to using oxygen to increase efficiency and power. 1.5/1.4 seems as sensible as any other set of numbers until and unless we hear from someone with even a modicum of expertise.

Re: TL5 Dirigible based on Spaceships help wanted
 

Looking at fuel I found a nice chart of BTU.
1 ton coal 16.2 million to 26 million
1 ton wood 9 million to 17 million
I imagine with coal's greater density than wood you could get much more out of a specific volume compared to wood. Whoops. Apparently they are around the same density.

1 gallon (I assume american) kerosene 135K
about 39.6 million per ton.

1 gallon gasoline 125K