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Re: Sky Monsters (w/spoilers)



Comments inserted below. I haven't seen the documentary yet, but did see some of the filming, some of the scripts, and some of the preliminary cgi work.
JimC


----- Original Message ----- From: "David Peters" <davidrpeters@earthlink.net>
To: <dinosaur@usc.edu>
Sent: Sunday, January 29, 2006 8:49 PM
Subject: Sky Monsters (w/spoilers)



Too bad the robo-pterosaur crashed.

Since it didn't have an onboard flight computer, the intent was to keep destabilizing it as Mike (the pilot) learned to control it, shooting for about a 50% crash rate and doing repairs between each flight. On the average, most repairs took about an hour.


Too bad they didn't listen to our own team of Conway and Cunningham for
configuration. That would have given them the critical control surfaces
to avoid the pitching problems they experienced (even with the addtion
of an airplane tail.)

It would still have been very unstable in pitch, but the wings would have been far more controllable had they been independent of the hindlimbs. To stabilize in pitch in any of the wing/hindlimb configurations the tail would have had to carry a download, and the pelvic geometry and muscle alignments just aren't capable of supporting a download for any substantial duration (it would be like us doing a leg-lift for hours on end). It is more likely that the living tailstructure usually carried a destabilizing upload, but the replica was usually flown with a download.

Too bad they listened to whoever told them to attach the wings to the hind legs. Needlessly complicated, fluttering trailing edge. Flaps down configuration almost always. I saw the credits, but I'm not naming names.

If you consider the three primary wing/hindlimb attachment scenarios to be those preferred by Padian, Bennett, and Unwin, the mechanical replica first flew the Bennett planform, then the Unwin planform (but without forward pointing pteroid). The planform preferred by Padian, Conway, and myself was not flown. Bennett's preferred planform is also a narrow wing, similar in some ways to Padian's, but with a narrow fillet turning aft near the elbow to attach to the ankle. Bennett's planform interacts with inboard wing tension rather differently than Padian's. In my mind, Conway's clay muscle model demonstrated rather clearly that the geometry of the pelvis and inner wing aren't really suitable for a wing/hindlimb attachment. I think the geometry of the mechanical replica may have been altered somewhat from life to minimize that problem.

Too bad someone told them the wings were furry or hairy. I've never seen that. Is it true?

Not as far as I know. It was flown without first. I told them that wing performance would deteriorate with fur. When fur was added, Mike (the pilot) reported that it did indeed reduce performance.

Too bad they used a Rhamphorhynchus sternum on the ornithocheirid. I kept wondering why the chest was so dang shallow.

The clay muscle model sculpted by John Conway was constructed on copies of the ornithocheirid sculptural casts that Hall Train did for the Fernback (sp??) Museum in Atlanta. The replica torso wasn't modeled too closely on the clay model, but the replica chest was probably as deep as it should have been. I think maybe some of the other replica torso proportions were off in ways that minimized the apparent depth of the chest.

Too bad they showed the grounded pterosaurs to be so ungainly and unable to completely fold up their wing membranes completely. Hopefully that paradigm will someday go extinct. Lots of bad anatomy and configuration there.

I didn't get involved in that, so can't comment. My own take is that pterosaurs were quite graceful when on the ground. I see no reason that they would not have been so. The Q species wing is capable of folding quite tightly upon itself. I don't know about some others.

Too bad they made the 'azhdarchid' to be a scavenger. It's really built more like a stork or heron.

In my mind, the azhdarchid Quetzalcoatlus is clearly a skimmer with a number of specializations for skimming and flight in ground effect. That said, I don't see any reason why they wouldn't pick up a tasty tidbit off the ground, should they notice one while hungry.


Aren't lots of animals usually fighting over
a carcass and didn't they just show how vulnerable a grounded pterosaur
can be by showing one being attacked by 'raptors'?

One of the interesting things about pterosaurs (quetz, at least) is that it would seem that on launch the hands are the last thing to leave the ground, and at the moment the hands do leave the ground, the animal is already going faster than any predator would likely be able to run. Since they didn't require a wind-assisted launch, I think the only way to dependably nail one would be an ambush attack from the front quarter. From any other angle, if the animal has one second of notice, you ain't gonna get him.


We really know alot more about pterosaurs than this program led us to
believe. Too bad we didn't get to see it.

A shortage of money and a lack of time were major issues, as they usually are. I was much impressed with the producer John Rubin and think he did the best he could with what he had to work with.


All the best,
JimC