Pterosaur Flight Plans (the idea that "they evolved flight naturally...defies common sense")

ICR ^ | August 31, 2009 | Brian Thomas, M.S.

[blackpacific]

It’s the difference between having gravity working for you, and having gravity working against you. Being able to flare does not imply the ability to achieve vertical flight.

[NicknamedBob]

"It’s the difference between having gravity working for you, and having gravity working against you. Being able to flare does not imply the ability to achieve vertical flight."

Quite so. Even cats can flare on landing.

[count-your-change]

NatGeo News Jan.7, 2009
The way a bird lifts off—using two legs—doesn’t make sense for pterosaurs, which would have had to heave their 500 pounds (227 kilograms) airborne using only their hind legs, the study says.
Instead, the “remarkably strong” animals apparently made a leaping launch in less than a second from flat ground, with no aid from wind or ledges.

NatGeo News Aug.19, 2009

The relatively few landing tracks suggest that the pterosaur landed like most modern birds, flapping quickly right before landing to slow themselves down, the researchers say.

For a 500lb. animal landing and take off without running would be remarkable in its self.

Cats can spread their legs out (flare) but they don’t flap them or take off in flight. Cats? Duh.

[NicknamedBob]

Evidently, pterosaurs were stronger animals than their equivalently-shaped bird analogs.

Most birds don’t depend very much on their leg strength to assist in flight capabilities. They can’t. The legs are simply not strong enough.

The birds use their wings for the most part to lift their bodies. The legs are simply folded up out of the way as soon as possible.

Pterosaurs may also have had a better “grasp” of the air they were manipulating, at least for take-off. Their ability to form airfoils from their wings may have helped them to glide, but it was probably not instrumental in the take-off procedure.

Birds these days depend quite a bit on the flight characteristics of their feathers. A bird stripped of its feathers cannot fly, but looks quite like a pterosaur, with the difference being the wing to body ratio.

I mentioned cats because it seems apparent that landing techniques had become instinctive and wide-spread long before actual flight abilities had developed.

[count-your-change]

So cats have an instinct to extend their feet to land like I do when I jump off a stool? Sounds more like a simple desire to avoid injury.

“Pterosaurs may also have had a better “grasp” of the air they were manipulating, at least for take-off. Their ability to form airfoils from their wings may have helped them to glide, but it was probably not instrumental in the take-off procedure.”

Then how do you think they got into the air?

[NicknamedBob]

We were discussing the “flare” technique of landing, not just simple shock-absorption. I’ve seen videos of cats jumping from high places. Essentially, they extend their limbs to grab as much air as they can, all the way down.

It is in the final approach that the flare technique can be seen. It transfers downward momentum to horizontal motion, and then spills as much motion as possible in a controlled stall. For cats, it isn’t very effective, but you can see the effort being made.

As far as how the pterosaurs got into the air in the first place, thrust is not flight. They were powerful enough to muscle their way into the air with their wings. Only then did they reshape the surface into something resembling an airfoil in order to sustain flight.

It’s similar to the tragic circumstances of Air Florida Flight 90, out of Reagan National Airport. They had thrust enough to climb, but because of ice buildup on the wings, they could not sustain their flight, and ended up no farther than the Fourteenth Street Bridge over the Potomac.

[ElectricStrawberry]

Someone once did a study of cats that fell from buildings from different heights....seemed that cats that fell from less than 6 floors had worse injuries than from more than 6 floors because the cats had more time to get into the “flying squirrel” position. It’s called the Feline High-rise Syndrome.

Probably more to do with transferring the impact across the entire body/torso instead of absorbing it all through the legs.

[count-your-change]

If you think cats are trying to parachute or glide, well, it seems of importance to you so as you wish.

And if you understand exactly how these 500 lb. animals got into the please inform the scientists studying them as they still have questions.
Yes, ice buildup on a wing could either make the aircraft too heavy for the lift the wings provided or change the shape of the wing so it simply didn't provide enough lift, etc. I understand the pterosaurs had excellent deicing though.

[blackpacific]

I doubt they were 500lbs.

Here is the problem I have hinted at, but no one got it, the pterosaur and the pterodactyl have the same problem, they need forward velocity to lift off.

Method I, Calculate Air Density:
Accurately calculate gross weight, then based upon wing area and wing structural limits determine the max wing loading, incorporate the fastest ground speed attainable by running and flapping, and then back out the required air density for liftoff.

Method II, Calculate Rotation Speed:
Accurately calculate gross weight, then based upon wing area and wing structural limits determine the max wing loading, incorporate mean standard day air density, then back out the required ground speed for liftoff.

If it turns out they have to run at 30MPH, based upon the assumption of a mean standard day atmosphere, and this is not structurally possible, given landing gear configuration and wingtip ground collision avoidance considerations, then maybe assuming a mean standard day is incorrect?

Here is another hint: The people of Noah’s epoch did not know what a rainbow was. Either they were too stupid to notice, or they truly had never seen one. Or maybe the characteristics of water were different also?

[count-your-change]

If they had large skeletons then the skeletons were covered with something, muscle and skin, sufficient to fly. If an animal as tall as a giraffe wighed a hundred or two pounds would it have enogh muscle to flap its wings?

But I do love engineer’s calculations since anything can be built with a pencil.

[blackpacific]

Bob Hoey in Calfornia used to build engineering models of soaring raptors, for various species. I don’t know if he is still alive, but he made it more than just a paper study, he did simulations, built prototypes, did flight test, and used the flight test data to correct the simulation. The college students who were privileged to work with him learned quite a bit about nature and about engineering flight test.

Some one like Bob can spend a lifetime understanding the engineering involved in let’s say, a pterosaur. What is it he is studying? Aristotle would call it the form. An engineer might call it a model. An architect might call it a blueprint, a scientist might call it an “intelligent design”, and none of them would have to say anything about how that design came to be. Answering a question about how something works is different than asking how something came to be. I have no problem letting Intelligent Design proponents segregate themselves from questions about origins. What ID does though, is inform inquiring minds about what is essential for a design to work, and this in turn provides information about whether such a design could come about by chance. Irreducible complexity is a valid checkpoint for any “random mutation” to be successful.

After studying statistics and advanced engineering mathematics for many years, it is quite clear to me that all life forms are brilliantly designed by deterministic computer programs, which are impacted by random input variables. The computer program provides the “whatness” or essence of a life form, the random input variables provide the uniqueness of each living thing. Random input variables make every maple leaf that has ever sprouted to be different and unique from every other maple leaf that has or ever will exist. So, a reasonable person would conclude that God uses random inputs to cause variety within a species, which is defined by deterministic computer code. So chaos has its place at the table of causes of this beautiful universe, but not the role that some modern minds would like it to have.