Re: Tom Knauff's newsletter

> But the 2 instruments measure different things. The yawstring (in
> theory) measures airflow angle at the fuselage. The inclinometer
> measures the difference between gravity and the opposite centripetal
> force - when in balance, the ball is centered.

True they measure different forces, but they derive appx the same info
for the pilot- status of turn coordination.

> The question is, which is a better measure of coordination?

BOTH! A good ball is more accurate, but it's responses are more
damped. The string gives you a good enough approximation for gaggling
and such, but no reason not to have a ball as well (works better in
icing too...) since they are available as 'space miser' instruments as
well (screwed in under an existing instrument by sharing two bottom
holes) and don't hog panel.

> Because of the difference in drag at the
> wingtips during the turn, the nose may yaw away from the center of the
> turn. The yaw string would show that, while at the same time, the
> inclinometer would be centered.

Again, the damped response of the ball vs the string. This effect is
amplified by using a low quality ball and a high quality string ;-)
It is recommended by some (Helmut Reichman was amongst this crowd)
that believe that a normal ball in fluid is too slow for soaring, and
instead used an inverted curved glass tube with a bubble of air. He
also used a string of course...

 > I should experiment in my LS6. Lord knows that I'm tired of looking
up
> at the gaggle :-).

We really do appreciate the warning though ;-)

-Paul