Jerry Davis wrote:
>
> Hi
>
> I am interested in your AOA meter. What have you planned? Are you
> just using one sensor? I don't have a Europa but it similar. I am
> looking for a good way of making a stall warner and the AOA idea is >
> intersting..
>
> Jerry
It will be patterned after LRI's pneumatic device
(see www.liftreserve.com - also many tech articles
there too). LRI's item is merely an airspeed
indicator-like device which gets pressure from two
probes (at a +/- angle to the slipstream), feeding
what would be the pitot and static ports were it
an ASI.
The sensor I have is a small plastic cylinder,
containing an aneroid bellows or whatever it's
called, moving the slider on the potentiometer
(-.43 PSI to +1.50 PSI range). By adding another
hose barb to the vented side of the device, and
plugging up the vent, differential pressure from
either side is sensed. The panel indicator can be
a panel meter or LED setup. The advantage of this
is that range and sensitivity is also adjustable
electrically, plus the easy addition of an audible
alarm and maybe even a stall indicator light, by
using a simple op amp comparator.
All theory at this point, though (best laid plans
of mice and homebuilders). Astute readers may
note that the PSI range looks insufficient at
Europa speeds, but only differential pressure is
involved, so testing shortly (on my Ford truck)
may disclose any problems.
Per LRI, Europa told them that the probe can be
installed on the aileron bellcrank inspection
plate under the wing.
Regards,
Fred Fillinger, A063
|