Subject: VAUX'S SWIFTS AND THIN AIR
Date: Aug 6 16:30:29 2002
From: jbinpg at shaw.ca - jbinpg at shaw.ca


If I remember my physics, higher altitudes mean less lift but also less
drag than at lower altitudes. I suppose this could mean slower powered
flapping flight but faster gliding. Since swifts are built for both,
perhaps they glide more at higher altitudes at faster speed.

Jack

----- Original Message -----
From: Ruth Sullivan <GODWIT at worldnet.att.net>
Date: Tuesday, August 6, 2002 10:21 pm
Subject: Re: VAUX'S SWIFTS AND THIN AIR

> Hello,
> When i played Golf in Garmish Partenkirchen Gemany ( high
> altitude) i got
> the longest drive of the tee ever maybe 25 yards more
> distance.The people
> behind me,was thinking i was a Golf Pro for hitting the ball quite
> far ,but
> straight also.I played Golf for years in Redmond Washington,and
> never had
> long distance drive as in the altitude in Garmish,there is
> something to this
> and it might be well that this Swifts taking advantage of.
>
> Ruth Sullivan Tacoma
> ----- Original Message -----
> From: "Wayne C. Weber" <contopus at shaw.ca>
> To: "CONNIE SIDLES" <csidles at mail.isomedia.com>
> Cc: "TWEETERS" <tweeters at u.washington.edu>
> Sent: Tuesday, August 06, 2002 1:13 PM
> Subject: VAUX'S SWIFTS AND THIN AIR
>
>
> > Connie and Tweeters,
> >
> > At first, it might seem logical that birds could fly faster at
> 4000 or
> > 5000 feet altitude than at sea level, because of the lower
> atmospheric> density, and hence less drag. However, because Vaux's
> Swifts (and most
> > birds) fly by flapping, lower atmospheric density would work against
> > this by simultaneously reducing the thrust (providing less air
> to push
> > against during each wingstroke). The net result, it seems to me, is
> > that altitude should make no difference to the speed at which birds
> > fly.
> >
> > Being a baseball fan, I've heard it claimed that it is a bit
> easier to
> > hit a home run in Coors Field, home of the Colorado Rockies (at over
> > 5000 feet altitude in Denver) than in other ballparks of similar
> > dimensions. I'm not sure if the statistics support this claim.
> > However, there's a big difference between baseballs and birds--
> > baseballs don't flap, and the batter can apply equal force
> regardless> of the altitude!
> >
> > I suspect that the reason the Vaux's Swifts near Mount Rainier
> seemed> to be flying faster is just that they were closer to the
> ground than
> > you usually see them, and hence the relative motion was greater.
> > Either that, or there was a Peregrine after them! :-)
> >
> > Wayne C. Weber
> > Kamloops, BC
> > contopus at shaw.ca
> >
> >
> > ----- Original Message -----
> > From: Constance J. Sidles <csidles at mail.isomedia.com>
> > To: <tweeters at u.washington.edu>
> > Sent: Monday, August 05, 2002 4:09 AM
> > Subject: Mt. Rainier
> >
> > < snip >
> >
> > Also in the area was a good-sized flock of Vaux's swifts. What was
> > unusual about them was their speed. They were flying around much
> > faster than the swifts do at the Fill. In fact, they were so
> fast that
> > they looked like an entirely
> > different species. I'm guessing that their increased speed was made
> > possible by the thinner air. Does anyone know if that is true?
> >
> > < snip >
> >
> > Connie, Seattle
> >
> > csidles at mail.isomedia.com
> >
> >
> >
> >
> >
>
>