"Andreas Maurer" wrote in message
...
On 18 Jan 2004 11:53:31 -0700, (Mark James Boyd)
wrote:


Just imagine what forces your movable weight will exert under a g load
different than 1? For example, when you are flying through a vertical
gust?

I'd imagine it will behave the same as an attached one pound ballast
weight on the upper part of the rudder of the glider used to
balance the rudder. Perhaps I'm missing your point here...

You are correct - but you have the horizontal stab that dampens the
motion (remember that the whole fuselage and tail acts as a weight!).

This is the cause why you need something aerodynamical to control your
pitch, and why weight shifting does not work.

It does not matter whether the damping is done by a horizontal
stabilizier or the airfoil/wing design of a flying wing.


Now this a very interesting point. Whether the weight is above
or below the C.G. seems to also have an effect.

Yes - and don't forget that the control authority of hang gliders is
extremely limited. If the gravity vector is not pointing "downwards"
(seen from the pilot's coordinate system) they have absolutely no
control at all. Inverted flight is out of question, and they are able
to fly their loopings only with some tricks.

Twaddle !
There are guys who fly HG inverted (they are complete nutters, but the point
is, it can be done)
Looping a HG requires 2 things,
1) speed
2) balls
fly very very, very fast, allow the bar to come forwards _slowly_ then
accelerate towards a full aft CofG position in a _controlled_ manner. (that
way you can do 54 consecutive loops in a HG) ((if you start high enough))

The CofG on a tailess aircraft (i.e. hangglider) is only secondary in the
control of VNE and stall, CofG is used for trimming but the primary speed
control of the wing is performed by the washout at the tips and on older
gliders through "luff lines" acting as "up elevator" as the speed built up
(not really used much these days)

bottom line, with a swept wing platform you can _make_ it operate within a
set airspeed range by limiting it's AUW and setting the AofA along the wing
section.

regards
Roy