Walter Banks wrote:
>
> Pic Dude wrote:
> > Why can't you just use the pressure *inside* the aircraft
> > for the static pressure (assuming it's not airtight)?  If
> > so, then it would be really easy to do using any of the
> > low-cost gauge or diff pressure sensors out there.
>
> Cabin pressure may be positive or negative. A simple way to
> get static pressure is the way many full size light A/C do.
>
> Ram air pressure is a tube pointing straight forward outside
> of the propeller wash. From a wing for example)  Static is
> a tube in parallel to the RAM air tube with the end capped
> and 3 or 4 small holes drilled in its sides. Both the tubes
> and the hole sizes are non critical.

This is definately the better way to do it, although I've found that as long as
you calibrate the sensors well enough and the cabin doesn't have too many holes,
the cabin pressure is "close enough". But then, I've only tried this in a pusher
configuration, a puller might be different.

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