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Old 02-11-2019, 06:15 PM   #1
Icelander
 
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Default Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Researching realistic* size constraints for flying creatures, I first found scientific literature that estimated several species of pterosaurs as having had a 30+ foot wingspans and having weighed up to 550 lbs., but still having been able to fly even without higher oxygen concentrations in the atmosphere.

Then I found this post, by lwcamp, whom I trust on GURPS stats for animals, because he knows a lot more about animals than I do.

Quote:
Originally Posted by lwcamp View Post
The more recent estimates place the mass of the larger Cretaceous pterosaurs at around half a ton, and able to leap into powered flight from a standstill.

For what it is worth, I find a weight of [length/(0.7 m)]^(3.333) kg to be a reasonable fit to the sizes of real world crocodilians over a wide range of species and life stages (from hatchling to the monster one ton bulls). Gomek the saltie was 5.5 m and 1 ton when he died. Large wild Komodo monitors tend to weigh in at around 35 to 50 kg (on an empty stomach - an important detail when they can gorge on up to 40% of their body weight in one sitting) and 2.5 meters in length. Captive (and probably obese) Komodos have reached 3 meters in length and about 100 kg in mass. For the more serpentine dragons, large pythons and anacondas are roughly matched by a weight of [length/(1.8 m)]^(3.333) kg, but the weight at the upper end of the length range varies by a lot (even within one species - some of the giants are fairly slender and others quite stout).

Luke
This pleases me, for, uh, reasons.**

Now, can anyone essay a guess at the likely ST scores for these recent scholarly estimates of real pterosaurs and whether they could have flown while carrying anything, i.e. some fraction of their Basic Lift, up to their BL or maybe up to Light encumbrance?

*So I could determine at what point fantastic creatures were sustained partially by mana and had a higher ST score in areas with mana, but would be unable to fly in No Mana Zones.
**What is even the point of Antarctic Space Nazis if they will not, once more, ride dinosaurs!?
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Last edited by Icelander; 02-11-2019 at 06:23 PM.
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Old 02-11-2019, 11:11 PM   #2
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Using the usual guidelines of 2*(weight in lbs)^(1/3), this gives a ST of 16. I often give particularly strong animals a multiplier of anywhere up to 1.3 for the species template, so up to 21 might be justifiable. However, given that the wings were big and powerful and attached to huge chest muscles but the rest of the body was pretty scrawny (except for that giant head), I'd be more inclined to give them ST 16, Arm ST 5, or even Arm ST 6 or 7. Lets say total ST of arms + body is 22. Since they mostly walk on their arms, and use their arms for flight, you could argue that this Arm ST counts for encumbrance (or just give them Lifting ST equal to Arm ST, if you are really going all accountant on points). So, a basic lift of around 100 lbs. At medium encumbrance they could carry 300 lbs; 200 lbs for light encumbrance. Gliding and powered flight would probably go by this level of encumbrance; take-off also does by the rules, but reality wise I'm not as sure. But since we are talking magic interdimensional dinosaur-riding Antarctic space Nazis, I'd say err on the side of cool. Maybe throw a bone to reality by saying that they only choose Nazis with smaller frames and light builds to be Azhdarchid riders (Azhdarchids being the taxonomic group of pterosaurs that includes Quetzalcoatlus, Hatzegopteryx, Arambourgiania - all giants of roughly similar size).

Oh, and technically pterosaurs are not dinosaurs. Although if a magic space Nazi is riding one I'm not going to get all pedantic about it.

Luke
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Old 02-11-2019, 11:26 PM   #3
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Quote:
Originally Posted by lwcamp View Post
Using the usual guidelines of 2*(weight in lbs)^(1/3), this gives a ST of 16. I often give particularly strong animals a multiplier of anywhere up to 1.3 for the species template, so up to 21 might be justifiable. However, given that the wings were big and powerful and attached to huge chest muscles but the rest of the body was pretty scrawny (except for that giant head), I'd be more inclined to give them ST 16, Arm ST 5, or even Arm ST 6 or 7. Lets say total ST of arms + body is 22. Since they mostly walk on their arms, and use their arms for flight, you could argue that this Arm ST counts for encumbrance (or just give them Lifting ST equal to Arm ST, if you are really going all accountant on points). So, a basic lift of around 100 lbs. At medium encumbrance they could carry 300 lbs; 200 lbs for light encumbrance.
Cool, thanks a lot.

Quote:
Originally Posted by lwcamp View Post
Gliding and powered flight would probably go by this level of encumbrance; take-off also does by the rules, but reality wise I'm not as sure. But since we are talking magic interdimensional dinosaur-riding Antarctic space Nazis, I'd say err on the side of cool. Maybe throw a bone to reality by saying that they only choose Nazis with smaller frames and light builds to be Azhdarchid riders (Azhdarchids being the taxonomic group of pterosaurs that includes Quetzalcoatlus, Hatzegopteryx, Arambourgiania - all giants of roughly similar size).
Now, now, just Grade-A, pure, finest reality.

Then the beasties can have +20% to ST in Low Mana and +40% in Normal Mana. That means if they can fly under their own power at No Mana, they've got power to spare in any higher mana areas. So Nazis won't ride dinosaurs on any world with realistic physics... but it's not like the World Tree confines them to only worlds with the same physics as ours.

Quote:
Originally Posted by lwcamp View Post
Oh, and technically pterosaurs are not dinosaurs. Although if a magic space Nazi is riding one I'm not going to get all pedantic about it.

Luke
When I tell people that "Nazis will once again ride on archosaurs!" people just give me strange looks. Uh, they actually do that even when I tell them that the Nazis will ride dinosaurs, but at least then they're looks of pity, not puzzlement.

It's a quote from the TV show Drawn Together (Foxxy vs. The Board Of Education):

Clara: "What is this unholy abomination?"
Wooldoor: "Hi Clara, you're just in time to witness a fake gay marriage for the health insurance."
Clara: "What? If gays get married, the institution of marriage will be destroyed! Societies will crumble! Rivers will run with blood! Nazis will once again ride on dinosaurs!"
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Old 02-12-2019, 12:14 AM   #4
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Realistically speaking, ST will be 'high enough to keep the dinosaur aloft with a reasonable margin to cover errors, bad luck, and variances in weight from eating and drinking'. This may not be all that strong in absolute terms, but bear in mind that we're applying force way out along the length of a quite long wing. If we assume Q. Northropi had a mass of 250 kg, 5m wings, and the center of lift 2m away from the body, limb torque is 2500N*m per wing (10N*m per kg), and peak at the bottom of a power stroke flying is significantly above that. By comparison, a 62 kg gymnast doing an iron cross is probably managing about 250N*m (4N*m per kg), so the total strength of the wing muscle is at least 10x greater, though the absolute strength is going to vary a bit because GURPS normally calculates ST at arm's length, and at wingtip the QN is applying a mere 500N, as opposed to the 620N applied by the gymnast (of course, a wing isn't an arm, so perhaps you measure at a different point along the wing length).

My problem with the higher end estimates of mass is that the power requirements are rather ridiculous -- because higher weight increases ideal and stall speed, power requirements for flight scale as the 3/2 power of body weight and wind up in the 3 kW range for 250 kg flier with a 11m wingspan.
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Old 02-12-2019, 12:36 AM   #5
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Quote:
Originally Posted by Anthony View Post
Realistically speaking, ST will be 'high enough to keep the dinosaur aloft with a reasonable margin to cover errors, bad luck, and variances in weight from eating and drinking'.
[...]
My problem with the higher end estimates of mass is that the power requirements are rather ridiculous -- because higher weight increases ideal and stall speed, power requirements for flight scale as the 3/2 power of body weight and wind up in the 3 kW range for 250 kg flier with a 11m wingspan.
Well, what kind of ST do you estimate would be enough?

And what kind of flight would you imagine for a pterosaur of 500+ lbs.?

If they eat fish, they need to be able to pluck the fish from where they find them. I guess pterosaurs of this size are unlikely to be able to almost hover as they feed, like seagulls seem to do. Albatrosses? Or like no bird, given how the wings are apparently very different.

What kind of Move is their standard 'cruising' speed, what's their stall speed and what's a plausible maximum Move?
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Old 02-12-2019, 03:06 AM   #6
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Depends what ST means. You've got these wing muscles, and they're amazing, but they're also attached to wings. The rest of the body is probably weaker than a ground-based animal of similar weight.

Cruising flight speed is probably about 20 (40 mph), stall is not well defined for flapping wings but they likely have a lot of trouble below move 10. Max move in a dive is potentially very fast but max safe speed considerably lower.
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Old 02-12-2019, 06:46 AM   #7
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Quote:
Originally Posted by Anthony View Post
Depends what ST means. You've got these wing muscles, and they're amazing, but they're also attached to wings. The rest of the body is probably weaker than a ground-based animal of similar weight.
Well, I'm primarily concerned with what ST means in the context of the ability to launch themselves into flight and to stay airborne. If they are able to lift themselves and a meal grasped in their mouth, along with having some margin of error, that can give us a basic, natural ST for flight purposes. As well as a SWAG of what multiple or fraction of their BL they could achieve flight while loaded with.

Which, in turn, would allow me to calculate their ability to fly with heavier loads if their natural ST were boosted by +20% or +40% (which implies an even larger boost in BL) through mystical means. Which would move them in a decidely dragonic direction.

Quote:
Originally Posted by Anthony View Post
Cruising flight speed is probably about 20 (40 mph), stall is not well defined for flapping wings but they likely have a lot of trouble below move 10. Max move in a dive is potentially very fast but max safe speed considerably lower.
Thanks.
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Old 02-12-2019, 06:57 AM   #8
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

I would have Wing ST suffer a -80% limitation if the wings cannot attack or manipulate, a -60% if they can attack but not manipulate or can manipulate but not attack and temporarily lose Flight while doing either, and a -40% if they can attack and manipulate but temporarily lose Flight while doing either. Wing ST would increase the effective HP of the wings for determining crippling injuries, but it would not impact overall HP.
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Old 02-12-2019, 08:12 AM   #9
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

Quote:
Originally Posted by Icelander View Post
If they eat fish, they need to be able to pluck the fish from where they find them.
They didn't.

Okay, we can't be absolutely sure that they didn't, but the current best thought is that they were stalking land predators something like storks. Really, really big storks. They probably ate a lot of baby dinosaurs, or the smaller dog-sized dinosaurs, and other animals of about the same size. Hatzegopteryx might have been able to choke down a human, but that's currently uncertain (but - magic interdimensional Antarctic space Nazis. In that setting they can eat people if you want them to).

So the Azhdarchids walked around on land like giraffe-tall storks, plucking dinosaurs from the fern prairies and fields of waving horsetails. They took off (we think) by tilting forward so their weight was on their wings, then jumping with their wings up into the air.
https://3.bp.blogspot.com/-6Ax_Rhlpv...Blow%2Bres.jpg (a couple giant Azhdarchids next to a human and a giraffe)
http://2.bp.blogspot.com/-Gj1161ZTs9...Blow%2Bres.jpg (feeding behavior in Arambourgiania)
https://static.scientificamerican.co...od-Zoology.jpg (hunting Hatzegopteryx)
https://static.scientificamerican.co...od-Zoology.jpg (hunting Quetzalcoatlus)
https://www.youtube.com/watch?v=ALziqtuLxBQ (animation of pterosaur launch)
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Old 02-12-2019, 09:09 AM   #10
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Default Re: Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

I was aware before how big they were, but Luke, you've given me a sudden appreciation for how terrifying they were.

With the strength of their forelimbs, is the mouth (beak?) designed such that it makes sense they might be able to pin a human down and pull more-bite-sized limbs off or otherwise pieces? I'm thinking like a predatory bird eats, such as a falcon or eagle.
It's not hooked, which seems like it would make that harder, and I don't know if the long neck/beak would mess with leverage.
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