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Re: avian flight



> > Indeed. And airspeed may become injurious or lethal...
>
> Only if you can't cope with it upon landing (or impact, as the case may
be).

Yes.

> > ; if you don't have a
> > library around which has Neues Jahrbuch für Geologie und Paläontologie,
tell
> > me, and I'll send you a scan.
>
> I don't, and would appreciate a scan, if there are no copyright issues
that
> would be violated by the scan.

I'll try to scan the paper this week. As for copyright... hm, I'm not trying
to sell anything, and I suppose the author wouldn't object that his ideas
are spread because I have never seen the paper cited anywhere, even though
Neues Jahrbuch is a relatively widely available journal.

Please tell me whether your computer can handle the size (9 A4 pages) and if
.bmp format works.

> > According to the formula Ebel gives, airspeed is directly proportional
to
> > the square root of air density...
>
> Inversely proportional to the sq. rt.

Oh, true :-]

> > I think Riet_s_chel's reconstruction looks more like the fossils.
> > Aerodynamic convention really is that way, but it only makes sense if
the
> > wings are continuous with the body, which is doubtful. I hope I can find
the
> > ref for the probability of that gap (probably it has been discussed
onlist,
> > it was in New Scientist).
>
> I tend to agree with you re the probability of the gap, but don't think it
has
> been demonstrated definitively either way.

True. It _looks_ more like the gap were present; the humeri are relatively
longer than in pygostylians.

> However, that is simply my personal
> opinion -- I've not done much of a search on the subject.   If  the gap
exists,
> Cl will drop across it, but will not go to zero.

True.

> > > > but on the other hand it does not take into
> > > > account tail area; these two effects more or less cancel each other
> > out.)
> > >
> > > No -- they don't.
> >
> > Statement against statement...
>
> True.  I calculated an estimate before making my statement.  You may wish
to do
> the same.

Oh. Well, I don't know any estimate for tail area; from illustrations, it
looks a bit larger than both gaps at once. I'll try to quantify that.

> > > ??? Steady-state, the Yalden wing would probably be most efficient at
a
> > lift  coefficient on the loose order of about 0.9.
> >
> > That formula is for parachuting, where there is no lift.
>
> The equations I used in the snipped stuff were for a lifting wing.

That's what I [intend to] say.

> > Neither estimate takes the tail into account. What is the effect of
tails to
> > total wing loading and lift in modern birds?
>
> It ranges from roughly -30 to +30 percent

How can it be negative?

> >         *Archaeopteryx* could most probably land on the ground, probably
it
> > used running landings not unlike a plane. Some confusion has arisen in
the
> > discussions here, I just claim Archie couldn't glide and couldn't land
in a
> > tree.
>
> You may well be right about landing in the tree, though it would appear
that he
> could have launched from one.  According to my calculations, he should
have been
> capable of a decent glide, though I suspect he was more of an active
flapper.
> I speculate that archie mostly launched by leaping and landed by running,
though
> it would appear that he could have launched by running as well.

Agreed. Just there weren't any trees higher than 3 m at Solnhofen, it seems.

> > Moving the wings back to the hips doesn't look feasible in Archie...
>
> Why would he[*] want to?

She* would want to because her center of gravity was most likely at the
hips -- good for bipedal running, bad for gliding. After all, she had a tail
of reasonable size.

*Another school dogma about the English language has hereby died ~:-| -- the
one saying that in English, unlike any other Indo-European language except
Persian, only explicit persons get grammatical genders. When we are at it,
the name *Archaeopteryx* is female, and *A. lithographic_a_* and *A.
bavaric_a_* are correct. German-speakers often don't know this... Ebel does,
and always writes "she" in his paper.

> > Too bad we don't have Ebel onlist.
>
> I agree.

:-)