On Fri, 09 Jul 2004 17:10:49 +0000, Robert Ehrlich
wrote:

Martin Gregorie wrote:

On Thu, 08 Jul 2004 17:37:11 +0000, Robert Ehrlich
wrote:

A raised tail (or elevator) doesn't mean there is a down force on it.

I didn't say "a raised elevator". I was talking about a tail surface
that is tilted laterally in relation to the wing and said "a raised
tip" to describe the direction of tail tilt. Please do me the courtesy
of reading what I wrote before sounding off about it.


I read what you wrote and my remark was not about the "raised tip"
or the tilt, but about "so you can tell that they fly like we do
with down force on the tail". Sorry if you misunderstood me, or
if I misunderstood you, remember English is not my native language.

Fair enough and I was forgetting the native language difference.

We agree too on gliders minimising down-force, but it is still there -
otherwise the folks who've flown and survived with the tail bolt
missing (much earlier thread this year) would be unlikely to have
survived the experience with an intact glider, but I digress.

I was meaning to point out two things: (1) you can deduce the flight
load on a bird's tail by watching how it uses tail tilt to control a
turn and (2) the kite family have down-force on their tail and a fair
amount of it or the tilt would be ineffective.

I'd like to hear about similar observations of other species for
comparative purposes.



--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :