Semi-Physics Questions

[Vella_Malachite]

Just wondering if anyone with a moderate knowledge of physics might be able to answer a question or two...

Basically, I have a character I'm making (If this thread should be in Media Discussions, could a kind mod please move it?:smallsmile:). She is an average height and moderately to heavily muscled (but not hugely bulky) 24-year-old woman, generally decked out in a normal (sensible) adventurer's costume with a sword and a couple of daggers plus a lightweight supplies bag. She has wings that are not big enough that she can fly in the conventional sense of the word, just so that she can jump further and higher than a normal, unaided person should be able to by a moderate distance and they aid considerably in acrobatic feats.

Question 1: How large should her wings be?

At one point in the story, she tries to save another character when he is pushed off an extremely high place (think around 100 metres, roughly) by jumping off after him to catch him. He is a normal size, slightly on the light side of average 16-year-old boy carrying only his clothes and a sword.

Question 2: Given she definitely can't fly them both to safety, given she couldn't even do that for herself, by how much, if anything, should the extra wingspan slow them down and, if you could, can you put that into terms of, say "Instead of being reduced to an unrecognisable pulp, they break most of their bones, rupture some internal organs and probably die anyway."?

Thanks in advance for all the help:smallbiggrin:

[Serpentine]

I saw a documentary years and years ago about the physiology of angels (well, that's the bit I remember, anyway). The bit that sticks out in my mind is that, according to it, angels should have breastbones sticking out more than a metre in front. 'Course, that was to fly, but it still might be worth keeping in mind that your character's chest would probably be quite different to a normal human's.

[thubby]

if i had to houserule it, I'd say about 1/2 the size of normal wings. judging by the 1/2 fiend picture. thats still maybe 6 feet.

[Serpentine]

I think this is a non-D&D-related story she's writing, so... no houseruling. Right?

[thubby]

I think this is a non-D&D-related story she's writing, so... no houseruling. Right?

if it would work for a game i don't see why it wouldn't work for a story. it just has to sound reasonable, after all.
as you mentioned, realistic wings are nigh impossible.

[Serpentine]

Fair enough, it's just the way you said it I thought I'd better check that you're not misunderstanding (unless I am...).

[Vella_Malachite]

Yes, 6 feet sounds reasonable, although it is open to debate, given my knowledge of physics; I can't really say how accurate it is likely to be. I trust you though:smallsmile:, and the breastbone thing won't be an option, as she only has wings because of a sadistic experiment several years ago.

That probably contributes to why they don't work as advertised...
:smallamused:

[Miklus]

Yes, 6 feet sounds reasonable, although it is open to debate, given my knowledge of physics; I can't really say how accurate it is likely to be. I trust you though:smallsmile:, and the breastbone thing won't be an option, as she only has wings because of a sadistic experiment several years ago.

That probably contributes to why they don't work as advertised...
:smallamused:

Try to compare her to a large bird, say a swan. It can weight some 25lbs and have a wingspan of...3 meters or so? A set of swan-like wings might add a little distance to a jump, maybe 20-30%. But she is still five or six times to heavy to fly. And the is the problem with the chest as mentioned.

And for the falling person scenario. 100 meters give a end velocity of 144km/h or about 90mph. With their combined weight, maybe she can slow it down about 10%? Let's say 80 mph. Ouch. But I would not rule out that they could somehow survive that, with immideatly and competent medical attention.

If you have them land on a steep slope with small trees and bushes and so on...And the wings could probably steer then around so they land feet first. That is obviously an advantage...:smallwink:

[Hazkali]

I'm not sure about the first part of your question; in many ways, that is a more biology-related question.

The second part of the question can be addressed by the equations here (http://en.wikipedia.org/wiki/Air_resistance), and as you can see, they are quite complicated and involve at least knowing the "reference area" of the wingspan, and experimental drag coefficients.

However, I would say this: in fiction, especially fantasy and sci-fi, real-world physics just gets in the way of plot. Just go with whatever fits and run with it; I personally will track down and hit any obsessive with my perspective stick if they whinge about how it's "not realistic".

[Miklus]

How about giving her a membrane between her arms and body like a flying squirrel? :smallbiggrin: Or like these guys:

http://www.youtube.com/watch?v=ttz5oPpF1Js

[Vella_Malachite]

Thanks everyone :smallsmile:!

This is all sounding quite good. I don't plan to follow real-world physics to a T, the plan is not to make it too unreasonable (for instance, she definitely isn't going to get up and walk away after this)

For anyone who is interested, the basic thing is that she is the cynical, mercenary type who mostly cares about her own skin and doesn't seem to be too bothered if anyone else dies, then at the end, the bad guy pushes the naive kid off this precipice and she throws herself off after him; she manages to grab hold of him and tries to slow their fall with her wings. He says to her:
"But your wings don't fly!"
She replies "I know."
As they near the ground, she realises they're still going to die if they fall like this, so she flips over and uses her body as a cushion, saving his life (possibly) at the cost of her own. (I think she eventually survives and isn't more companionable, but she does get pretty mauled.)

[thubby]

you could write it so she uses the tower for drag. her arms and legs would basically be flayed. or she could try to dig in one of her knives. trees always work as mentioned

[RandomLogic]

I would say that she should have wings that are about double the length of her arm, or essentially twice her height (total wingspan) which is a decent approximation for most aircraft I believe.

Unless self propelled, the maximum acceleration of anything towards the ground is going to be 9.8 m/s^2 (or 32 ft/s^2) so basically its going to be curling into as tight form as possible (tucking the wings in tight, headfirst kind of thing) and hoping the other person spreads out their body so to increase drag. Perigrin falcons can hit about 220 mph in free fall but are obviously much smaller than people. Also if you want it accurate, please do not have them flap their wings to go faster downward, I'm positive that doesn't work.

Also, something like 1 square foot of resistance when free falling reduces speed significantly, so I would accept the fact that turning over, fulling extending 12 foot wings would significantly reduce airspeed. People have fallen out of aircraft and gotten up and walked away from hitting the ground.