[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Screaming dromaeosaur biplane killers of the air



Jim Cunningham (jrccea@bellsouth.net) wrote:

<None of which constitutes biomechanical evidence of poor flight ability.
It only impacts which flight 'niches' may have been more often used.  As
you no doubt know, flapping flight calculations indicate that archie could
probably climb at about 100-200 fpm, could glide about 2/3 as well as a
pigeon (or closer, if the tail could cascade -- tail cascading, or the
lack thereof, has not been demonstrated), and could avoid those flight
niches that require highly developed elevator muscles.  What's so
inefficient about that?  It seems sort of like calling a swan a slow
flyer.>

  No one has demonstrated the range of motion *Archaeopteryx*' humerus
could move in, and this impacts directly on its ability to produce
adequate thrust to fly via flapping. With a restricted humerus and absence
of an advanced humeral elevator system (the one it has has the
coracobrachialis muscle that would pull the humerus _up_ at the level of
the glenoid, if slightly lower, and would only have twisted the humerus in
its socket), the flapping idea falls short of proving Archie could flap
above horizontally.

  As for swans, I was not speaking of gross speed, though i may have
nipped myself in the bud there; high-speed flyers was a term I used for
falcons and swifts at the like, the fastes flyers whose wings grant them
this ability along with their combination of aerobic and anaerobic brest
muscles; my use of "low-speed" flyer was not to indicate that it was
_slow_ in general, as a woodcock is slow (I could run faster than it
flies) but that it lacked the high-speed adaptations that I was listing.
Indeed, a swan's wing has nearly the same aspect as many eagles, which as
I had more earlier pointed out, is possibly an adaptation to flying with
great size.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com