Since you have shown interest... manned aircraft tend to use an horizontal cylindrical or conical probe with parallel slots along but slightly either side of rotational axis. Is this just a simple drag balance device or do they measure pressure and servo drive to balance?
I think that you are referring to a combined pressure head. This is anular in section, with the tube through the centre containing pitot (dynamic) pressure, and the outer tube, vented by the slots you describe, containing static pressure. The pitot and static pressures feed the main aircraft pressure instruments, to whit...
- The Airspeed Indicator (ASI) is a comparative pressure gauge, comparing the two.
- The Altimeter is an absolute pressure gauge, measuring Static pressure.
- The Vertical Speed Indicator (VSI) measures the rate of change in static pressure.
Apart from that the errors in this tend to be a function of AoA, these aren't AoA devices in any way.
Having said that, there is a device called a yawmeter, which typically has a cone or cylinder pointed into the airflow, with holes or slots something like 45° above and below the (nominal) horizontal plane. Comparing the two pressures with static can give a very good measurement of AoA (or if mounted in the other plane, sideslip angle). I can't recall ever seeing such a device on an aeroplane but it is quite commonly used in wind tunnels - a standard reference such as
Pope and Goyne may offer some more detailed information.
Try this link for some further information too.
G