REFLECTOR: Sparrow strainer - I'm confused...

[Scott Derrick]

>
>   If the Sparrow Strainer were inverted to provide nose down force as 
> airspeed increases - this contributes to negative stability.  Which is 
> to say, as the aircraft speeds up, the nose will want to pitch down 
> ... which helps the aircraft speed up, which helps the nose pitch down 
> further ... which helps the aircraft speed up - you get the idea.  
> Imagine this situation if disoriented in IMC.

Anybody who's actually flown A Velocity with the sparrow strainer 
installed both upside down, not installed and downside down, knows that 
the above statement is completely and utterly false.  The plane will in 
no way act in the above manner.   What is described above is negative 
pitch stability, which the strainer is way way way to small to induce. 
In fact it's too small to induce neutral stability when installed upside 
down.

Speaking from experience, upside or downside down installation changes 
the pitch stability in a slight way, in fact its hard to tell the 
difference in pitch stability, but it does make a slight positive  
change in pitch trim in cruise.

Scott