Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

[thrash]

Originally Posted by Celjabba

Looking at the launch video, would an underbelly harness (like an hand glider tripod) work better than a saddle for the rider ? The pterosaur spine seem vertical on land.

NASA has proposed VTOL design where the pilot transitions from standing to lying flat as the aircraft takes off: https://www.scientificamerican.com/a...stealth-plane/ This wouldn't be very different. In fact, it might be easier to take the sudden surge with feet in stirrups, rather than relying on straps or a harness.

[Icelander]

Originally Posted by Celjabba

Looking at the launch video, would an underbelly harness (like an hand glider tripod) work better than a saddle for the rider ? The pterosaur spine seem vertical on land.

In flight, it seems fairly practical. I'm concerned, however, that anything similar to a hang-glider tripod might interfere with the ability of the pterosaur to launch itself airborne using its wings as extra legs.

[bert]

This thread is totally awesome! Thanks everyone.

Yes I am thinking of how to add these monsters somewhere....

[dcarson]

I'm gearing up for a GURPS Space 1889 campaign on Venus so dinosaurs are a given. This means that there will be a area where the local tribes of lizardmen ride pterosaurs.

[Icelander]

Originally Posted by dcarson

I'm gearing up for a GURPS Space 1889 campaign on Venus so dinosaurs are a given. This means that there will be a area where the local tribes of lizardmen ride pterosaurs.

So, will your pterosaurs be strong enough to lift off and fly useful distances carrying a rider through the power of unspecified handwavium or through adaptations to local mana fields*, where they can obtain part of their food requirements and use the magic to be much stronger for their weight than in No Mana Zones?

*The far more respectable specified handwavium.

[Rupert]

Originally Posted by Icelander

So, will your pterosaurs be strong enough to lift off and fly useful distances carrying a rider through the power of unspecified handwavium or through adaptations to local mana fields*, where they can obtain part of their food requirements and use the magic to be much stronger for their weight than in No Mana Zones?

*The far more respectable specified handwavium.

My standard handwavium for such situations is a slight increase in oxygen partial pressure and a substantial increase in total atmospheric pressure along with a reduction in local gravity. That last isn't applicable in the case of Space:1889's Venus, but the other two can apply.

[Icelander]

Originally Posted by Rupert

My standard handwavium for such situations is a slight increase in oxygen partial pressure and a substantial increase in total atmospheric pressure along with a reduction in local gravity. That last isn't applicable in the case of Space:1889's Venus, but the other two can apply.

What possible unintended consequences are there to increasing the oxygen partial pressure and the total atmospheric pressure in a world with pterosaur riders and visitors of the Space: 1889 or similar persuasions?

What will be the effects on other wildlife?

How does this affect human endurance and comfort?

What is the effect on the airship the visitors might have and the steam engines they no doubt use?

What happens if the visitors fire cannon or the Maxim gun in an atmosphere of, say, around 25-30% oxygen, and with a significant* atmospheric pressure increase?

What about a forge? How would this atmosphere affect the attempts of the omni-capable Scottish engineer to make spare parts for a downed airship in the Venusian wilds?

*How much would you mean by 'significant', I wonder?

[Rupert]

Originally Posted by Icelander

What possible unintended consequences are there to increasing the oxygen partial pressure and the total atmospheric pressure in a world with pterosaur riders and visitors of the Space: 1889 or similar persuasions?

More oxygen makes getting oxygen from the air an into the muscles a bit easier. Denser atmosphere means it's easier to fly.

What will be the effects on other wildlife?

It's a world of dinosaurs in swampy jungle and mist. So, it means big dinosaurs.

How does this affect human endurance and comfort?

Slightly more endurance, easily offset by the awful humidity and heat. Worse, no amount of starching will keep an outfit properly crisp and collars stiff.

What is the effect on the airship the visitors might have and the steam engines they no doubt use?

The airships use internal combustion engines, and airships work fine on Space:1889 Venus (unlike etherwood vessels - Venus destroys etherwood).
[/quote]
What happens if the visitors fire cannon or the Maxim gun in an atmosphere of, say, around 25-30% oxygen, and with a significant* atmospheric pressure increase?[/quote]It goes bang! like normal, the bullets slow down faster (but not super fast - you won't notice except in long-range firefights), and you want to be a bit cautious about your muzzle flash around flammables. However, Venus is really wet and humid, so it's not too much of a problem (until the GM decides it is).

What about a forge? How would this atmosphere affect the attempts of the omni-capable Scottish engineer to make spare parts for a downed airship in the Venusian wilds?

Well, good luck getting dry wood for that.

How much would you mean by 'significant', I wonder?

Wild guess of 1.5-2 atmospheres. Enough that lift will be noticeably increased (maximum speeds will also drop, though).

[Icelander]

Originally Posted by Rupert

More oxygen makes getting oxygen from the air an into the muscles a bit easier. Denser atmosphere means it's easier to fly.
It's a world of dinosaurs in swampy jungle and mist. So, it means big dinosaurs.

Slightly more endurance, easily offset by the awful humidity and heat. Worse, no amount of starching will keep an outfit properly crisp and collars stiff.

The airships use internal combustion engines, and airships work fine on Space:1889 Venus (unlike etherwood vessels - Venus destroys etherwood).

It goes bang! like normal, the bullets slow down faster (but not super fast - you won't notice except in long-range firefights), and you want to be a bit cautious about your muzzle flash around flammables. However, Venus is really wet and humid, so it's not too much of a problem (until the GM decides it is).

Well, good luck getting dry wood for that.

Wild guess of 1.5-2 atmospheres. Enough that lift will be noticeably increased (maximum speeds will also drop, though).

Ah, ok, thanks.

I gather, then, that it would not be wildly implausible to propose humans living in a place with a pressure of 1.5-2 atmospheres, with atmospheric oxygen around 30% in the air?

But could such humans (or human like natives) ever form a civilization?

Would they have to find highlands and mountains, where it might be drier and the air pressure less?

Huh, and where they might be competing with pterosaurs with living space!

[lwcamp]

Originally Posted by Icelander

What possible unintended consequences are there to increasing the oxygen partial pressure and the total atmospheric pressure in a world with pterosaur riders and visitors of the Space: 1889 or similar persuasions?

What will be the effects on other wildlife?

How does this affect human endurance and comfort?

What is the effect on the airship the visitors might have and the steam engines they no doubt use?

What happens if the visitors fire cannon or the Maxim gun in an atmosphere of, say, around 25-30% oxygen, and with a significant* atmospheric pressure increase?

What about a forge? How would this atmosphere affect the attempts of the omni-capable Scottish engineer to make spare parts for a downed airship in the Venusian wilds?

*How much would you mean by 'significant', I wonder?

A few notes ...

Flammability usually scales with the oxygen fraction, rather than the absolute partial pressure. The main idea is that with 20% oxygen and 80% inert gasses (like Earth), every oxygen molecule that reacts has to share the energy of reaction with four other gas molecules, so whether it is one atmosphere total pressure or ten, you still get the same fraction of usable energy being sapped off that can't go into sustaining your fire. Now, a more detailed investigation gives some dependence on absolute partial pressure, but not a lot. So if you bump up the O2 partial pressure to 0.3, but increase the total atmospheric pressure to 1.5, the flammability won't change.

Counter-intuitively, increased pressure doesn't change the thermal conductivity of the air.

At oxygen partial pressures in excess of 0.5 atmospheres, you start getting into oxygen toxicity territory. This typically manifests as pulmonary inflammation and retinal detachment, with nervous system toxicity at very high partial pressures (> 1.5 atm.). For pulmonary inflammation, you experience coughing, a burning sensation upon inhalation, and shortness of breath. In extreme cases it can lead to alveolar collapse and suffocation. The onset of symptoms ranges from over half a day to as little as 3 hours at many times the threshold oxygen partial pressure.

For atmospheric pressures above 2 atmospheres, you'll start to be affected by narcosis. At low levels it can manifest as a decrease in anxiety and increase in confidence. As the pressure climbs, judgement, reaction time, and coordination can be impaired while the victim becomes indecisive and has difficulty focusing, multi-tasking, and completing unpracticed tasks. This can be accompanied by difficultly in visual focusing, giddiness, anxiety, exhilaration, overconfidence, paranoia, or depression, depending on the victim, her personality, and history. At extreme concentrations, pressure narcosis leads to confusion, hallucinations, long delays in reaction time, dizziness, possible hysteria or panic, loss of recall, stupefaction, hallucinations, euphoria, sense of floating, progressive blackout, loss of sense of progression of time, unconsciousness, and death. The effects are cumulative with other mind-altering substances; alcohol and cannabis in otherwise safe amounts can lead to serious affliction. Nitrogen narcosis occurs within minutes of breathing high nitrogen pressures, and disappears within minutes of breathing at standard pressure.

If you have relatively high levels of carbon dioxide in the air, you can suffer from hypercapnea. Clinical symptoms include tiredness, irritability, difficulty thinking, confusion, drowsiness, headaches, and trouble sleeping. Symptoms manifest within hours, and likewise disappear after several hours breathing air with reduced CO2.

Interestingly, while the impairments of pressure narcosis and hypercapnea are cumulative, the symptoms often mask each other, making it more difficult to realize what is happening if both occur at the same time.

Rapidly going between the high pressure atmosphere and a more normal pressure risks decompression sickness - most likely aching joints, but also rashes, swelling itchiness, vertigo, nausea, hearing loss, partial paralysis, limb weakness, malaise, generalized aches, fatigue, headache, and possible brain injury or difficulty breathing.

Increased atmospheric density means that airships get more lift from a given volume of lifting gas.

Given the same insolation, winds will be slower but will exert greater aerodynamic forces for the same speed. Venus, with more insolation, can expect to have more damaging winds and worse storms.

The dense air makes it take somewhat more effort to breathe in and out. This might be countered by the increased oxygen, which means you don't have to breathe in as much.

Luke