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Scientist claims Pterodactyls were too heavy to fly

 
 
Reply Thu 2 Oct, 2008 04:20 pm
Pterodactyls were too heavy to fly, scientist claims

Quote:
http://www.telegraph.co.uk/earth/graphics/2008/10/01/sciptero101.jpg

They carried away Raquel Welch in One Million Years BC and were ferocious in the Jurassic Park series of films.

But now it seems pterodactyls, the terror of the prehistoric skies, may have struggled to get off the ground.

The new research claims that the ancient reptiles, which could grow to the size of small aeroplanes, were too heavy to fly - even with their massive wings.

The problem, according to a leading scientist, is that they could not flap fast enough to create the thrust to keep their enormous bulk airborne.
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Type: Discussion • Score: 13 • Views: 8,277 • Replies: 56

 
edgarblythe
 
  1  
Reply Thu 2 Oct, 2008 04:29 pm
@Robert Gentel,
I'll wait for them to sort it out.
0 Replies
 
Merry Andrew
 
  1  
Reply Thu 2 Oct, 2008 05:04 pm
@Robert Gentel,
Seems to me someobody or other once proved that the aerodynamic involved make it quite impossible for bumblebees to get airborne. But, thankfully, bumblebees can't read. I suspect pterodactyls didn't know how to read either.
Foxfyre
 
  1  
Reply Thu 2 Oct, 2008 05:05 pm
Knowing next to nothing about aerodynamics, the first thought that came to mind is: so are 747's.
Robert Gentel
 
  3  
Reply Thu 2 Oct, 2008 05:07 pm
@Merry Andrew,
Merry Andrew wrote:
Seems to me someobody or other once proved that the aerodynamic involved make it quite impossible for bumblebees to get airborne. But, thankfully, bumblebees can't read.


Is it aerodynamically impossible for bumblebees to fly?
Quote:
The basic principles of bumblebee flight, and insect flight generally, have been pretty well understood for many years. Somehow, though, the idea that bees "violate aerodynamic theory" got embedded in folklore.

According to an account at www.iop.org/Physics/News/0012i.1, the story was initially circulated in German technical universities in the 1930s. Supposedly during dinner a biologist asked an aerodynamics expert about insect flight. The aerodynamicist did a few calculations and found that, according to the accepted theory of the day, bumblebees didn't generate enough lift to fly. The biologist, delighted to have a chance to show up those arrogant SOBs in the hard sciences, promptly spread the story far and wide.

Once he sobered up, however, the aerodynamicist surely realized what the problem was--a faulty analogy between bees and conventional fixed-wing aircraft. Bees' wings are small relative to their bodies. If an airplane were built the same way, it'd never get off the ground. But bees aren't like airplanes, they're like helicopters.

0 Replies
 
Robert Gentel
 
  2  
Reply Thu 2 Oct, 2008 05:09 pm
@Foxfyre,
Foxfyre wrote:
Knowing next to nothing about aerodynamics, the first thought that came to mind is: so are 747's.


747's don't flap their wings with muscles, the calculations would be significantly different.
0 Replies
 
littlek
 
  1  
Reply Thu 2 Oct, 2008 06:46 pm
@Robert Gentel,
So.... the wing-flaps were for gliding, maybe?
0 Replies
 
gungasnake
 
  1  
Reply Thu 2 Oct, 2008 06:56 pm
Pteradactyls were around 50 lbs; the Big Bend pterosaurs were more like 1000 with 60' wingspans. The heaviest birds which can take off or land today are around 30 lbs. Think something might have changed or something?
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farmerman
 
  4  
Reply Thu 2 Oct, 2008 07:58 pm
The first of the OrderRhamphorhynchus was a Jurassic age "flying" reptile that , just like later pteronodons and the "Huge" versions of Pterodactyls, showed hollow bones, forward pointing teeth (presumably for grabbing pelagic sealife), very elongated humerii and radii/ulnae.
Several studies have been done that looked at the lift and glide ratios for a "model pteronodon" (The study looked at whether it could stay aloft, and it could) As all tge early and later derived flying reptiles show, they all have a grasping fingers at the pteroid bones and fingers on the manus. This appears to be adaptation for hanging to rocky cliffs or trees.
The shoulders of all the flying reptiles contain a special bone, the Notarium, which was a shoulder "girdle" that acted as a strenmgthening point for the shoulder. Other bones show adaptation for flying in pterodactyls and pteronodons. These two families show deepened sternal bones (like turkeys or flamingoes) , while Rhamphorhyncus, the earlier flying reptile, shows a smaller , less developed sternum.

Rhamphorhynchus clearly shows that it was an earlier state of the evolution of flying reptiles . The Rhamphorhync"oid" style of flying reptile were replaced by the pterosaur"oids" in the transition from Jurassic to Cretaceaous time.
Rhamphrhyncus did fly, and by morph similarity, so did the pterosaurs. I think that the scientist who stated his opinion should look at a fossil of an Albatross . These birds are terrible at getting into the air , but soar marvelously , sometimes for weeks at a time.
Many researchers have looked at similitude of form and function and evaluating convergence of this similitude among unrelated families(eg birds and bats, catii and bromeliads, etc)
0 Replies
 
rosborne979
 
  2  
Reply Thu 2 Oct, 2008 09:35 pm
@Robert Gentel,
Quote:
Scientist claims Pterodactyls were too heavy to fly

Yeh, those big wings and hollow bones are probably just for show. They probably ran around on stubby little legs dragging their wings in the sand and snapping up fish that threw themselves onto the shore.

It's pretty clear that Prof Soto has underestimated the mechanics of this animal. I would guess that strapping an accelerometer onto a bird and extrapolating the results isn't a good way to understand Pterosaurs.

edgarblythe
 
  2  
Reply Thu 2 Oct, 2008 09:37 pm
@rosborne979,
Yeah, if they couldn't fly they would have been helpless.
gungasnake
 
  1  
Reply Thu 2 Oct, 2008 09:44 pm
When Langston first tried to put Texas pterosaur skeletons together (along with man-made material sections for missing parts) he wanted to make the wings 60' in span because the bones he DID have indicated that. The aeronautical engineering department at UT basically told him something like "Hey, daddyo, you're making us look stupid enough putting those things together with 40' wingspans but we'll tolerate that; but no way in hell are we letting you put em together with 60' spans". In other words, they knew that the things were monsterously beyond what was mechanically possible for something made of flesh and bone.

And then within the last five years or thereabouts more complete specimens have turned up in Mexico and Israel which leave no doubt as to the 60' wingspans.

These things flew, but they clearly could not fly in our present world.
0 Replies
 
dlowan
 
  1  
Reply Thu 2 Oct, 2008 09:50 pm
@edgarblythe,
And they would have stopped having wings pretty damned fast.

gungasnake
 
  0  
Reply Thu 2 Oct, 2008 09:51 pm
@dlowan,
Correct. In our present world, wings would become vestigial long before the creature ever got to 1000 lbs.
0 Replies
 
Robert Gentel
 
  2  
Reply Thu 2 Oct, 2008 09:52 pm
@rosborne979,
rosborne979 wrote:
It's pretty clear that Prof Soto has underestimated the mechanics of this animal.


Or the atmosphere it lived in.
gungasnake
 
  1  
Reply Thu 2 Oct, 2008 10:02 pm
@Robert Gentel,
It's not atmosphere; probably gravity. An atmosphere thick enough to create buoyancy would burn the creature to cinders as he tried to breath it and snap his wings the first time he tried to hold them in a turn in it.

rosborne979
 
  2  
Reply Thu 2 Oct, 2008 10:06 pm
@Robert Gentel,
Quote:
Or the atmosphere it lived in.

Yes. There are number of possibilities which simply can't be extrapolated from putting accelerometers on birds. Atmosphere is only one.


0 Replies
 
rosborne979
 
  2  
Reply Thu 2 Oct, 2008 10:06 pm
@gungasnake,
Quote:
It's not atmosphere; probably gravity.

Gravity doesn't change.
Robert Gentel
 
  2  
Reply Thu 2 Oct, 2008 10:08 pm
@gungasnake,
The oxygen-rich theory is not about the density of the air but the physiological effect on the Pterosaurs.
gungasnake
 
  0  
Reply Thu 2 Oct, 2008 10:12 pm
@Robert Gentel,
Still doesn't work. If nothing else, bones don't depend on oxygen and the bones wouldn't take the stress.
0 Replies
 
 

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