REFLECTOR: sparrow strainer (old post)

[Ronnie Brown]

I believe Steve has this backwards - unless he meant that the sparrow
strainer pushes the elevator DOWN which makes the plane go UP.

My thinking is that as airspeed decreases, as in pitched up, the airflow
decreases and the sparrow strainer pressure is decreased allowing the
elevator to go up, and the plane pitches down.

And the opposite effect when airspeed increases when the plane is
descending, the airflow increases, causing more sparrow strainer pressure,
which forces the elevator down, pitching the plane up.

All of this helps stabilize the Velocity at a constant pitch trim position.
Seems to work!  My sparrow strainer chord angle is pointed down (about 15-20
degrees) compared to the elevator.  I.e.. the nose of the strainer is
pointed down when the elevator is level.

Ronnie Brown

----- Original Message -----
From: "Pat Shea" <xl340hp@yahoo.com>
To: <reflector@tvbf.org>
Sent: Wednesday, May 21, 2003 10:36 PM
Subject: Re: REFLECTOR: sparrow strainer (old post)


> Sorry, another old post I flagged for reference that's
> raising questions in my head:
>
> <<Brian...
>
> The sparrow strainer inverted wing has 19 degrees of
> incidence relative to the elevator...That is, if the
> elevator is set to zero incidence  cord line,
> then the cord line of the sparrow strainer is set so
> the leading edge is up 19 degrees compared to the
> trailing edge...That pushes the back of the
> elevator up at higher speed...Relieves a lot of trim
> spring pressure and gives the stick a much softer
> feel...
>
> Hope that helps...Your mileage may very...
>
> Steve...
>
> Standard Wing-RG-MT 3 blade cs prop...>>
>
> Hmmm, I thought the sparrow strainer/inverted wing was
> meant to act as a pitch dampener - not a trim tab. I
> just mounted mine using the side templates supplied by
> the factory (which set the sparrow's incidence) and it
> has very little angle of attack relative to the
> elevator. I can't see how this it is going to relieve
> much spring pressure at any airspeed. Was the 19
> degrees of relative incidence a mod??
>
> Pat
>
>
>
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