d b wrote:

You got it. Stability isn't really defined as the aerodynamics of the plane.
It is defined as what the pilot sees. You didn't mention that
dynamic instability is quite common and is usually not a serious issue.

???

I think you are mixing it all...

Stability *is* defined by aerodynamics and is quite difficult for a non
specialist pilot to determine...

*Dynamic* instability is very serious and may result in a loss of
control (pilot induced oscillations) and/or overloading

*Static* instability in not a serious issue as long the glider remains
dynamically stable, which is the case except with very static-unstable
designs - but it should not be "quite common" because the certification
standards do require a positive static stability (whether this
requirement is pertinent or not is another debate)


In article , "Arnold Pieper"
wrote:

But aircraft need to have a predictable behaviour and a predictable response
to control inputs.

Unstable aircraft have a very predictable unstable behaviour ;-)

And unstability (either static or dynamic) does not mean that control
inputs response (at least in its primary effect) is inverted...


--
Denis

R. Parce que ça rompt le cours normal de la conversation !!!
Q. Pourquoi ne faut-il pas répondre au-dessus de la question ?