Re: Pterosaur Aerodynamics

["James R. Cunningham" <jrccea@bellsouth.net>]

For any of you all who are interested in pterosaur aerodynamics, I am
forwarding the following message from Alasdair Lovatt, from New Zealand
(deslov@infogen.net.nz).  I'm sure he would like to hear from any of you who
have time to correspond, and I'd appreciate it if some of you would tell him
how to subscribe to the dino list since I think he would enjoy it.  Though
I'm on the list, I don't have a clue how to get on it.
All the best,
JimC

Des wrote:

> Dear James Cunningham,
>
> I sent the email shown below, to Fabio Dalla Vecchia.
> He told me that you are the expert that would be able to address my
> questions of pterosaur aerodynamics and physical properties.
>
> I hope you find these questions interesting,
> as I am sure I will find your answers enlightening.
>
> I look forward to your reply, but please do not go to too much trouble.
> If you have reference texts, or websites, on the topic, then I would be
> interested in them.
>
> Thankyou in advance.
> Yours
> Alasdair Lovatt
> deslov@infogen.net.nz
>
> EMAIL FOLLOWS;
>
> Dear Fabio Dalla Vecchia
>
> I am an amateur interested in aerodynamics and flapping flight of
> animals.
> I read an article about pterosaurs and it mentioned your name.
> The article talked about how the Pterosaur fed.
> I have many questions.
>
> 1a) Is there any evidence of muscle attachment points just behind the
> eyes, and also on the rear of the head?
>
> 1b) Do you have any data or estimates of the flight speeds of these
> animals?
>
> 2) Noting that the creature flew over water, very closely to the
> surface, what gave it the ability to take-off again if it was forced to
> land (or rather; "water")?
>
>
> 3a) How well did the creature float? Body mass and volume, hence
> density.
>
> 3b) What proportion of it would have been above water when floating?
>
> 4a) Did it have webbed feet for paddling and ski type landings on the
> water?
>
> 4b) Do the feet show any form of flattened surfaces on their under side,
> or
> skin extensions between the toes?
>
> 4c) What purpose do the feet appear to be most adapted for?
>
> 5a) Has there been any estimate made for the speed that it could run, or
>  otherwise makes it's way across horizontal ground?
>
> 5b) Has anybody looked at the deformation in the tracks to see what the
> thrust of the feet were, and knowing the mass of the animal (from size
> infered from foot & step length) the speed could then be estimated.
>
> 5c) Has there been a comparative study of other birdlike animals with
> legs of similar proportions (lower to upper bone lengths), and muscle
> structure or mass?
> This would give an idea of the power and speed of the legs.
>
> The interesting result is to find whether the expected achievable
> running speed {in (5)}, is sufficent for take-off, based on estimated
> flight
> characteristics {in (1)}.
>
> 6a) Has anybody done a study of the method of taking-off for these
> animals?
>
> 6b) Do you think the vertical surface of the crest, could also have
> played a part in steering, and lateral (yaw and roll) stability in
> flight, acting as a
> form of vertical canard?
>
> 7a) Do you have any pictures of the likely skeletal posture, and muscle
> attachment point, and relative strengths of muscles?
>
> 7b) Are there any plans to make any real or virtual skeletal
> reconstruction,
> to infer the stance, posture, motions of this animal?
>
> 8a) Do you think it had feathers, hairs (or filaments of some sort), or
> scales of any sort, or just a
>  membrane?
>
> 8b) Do you know of any evidence that they secreted oils on their wing or
> body surfaces?
>
> Looking forward to hearing from you.
>
> Alasdair Lovatt
> deslov@infogen.net.nz