Dynon Avionics Heated AOA/Pitot Probe - Manual (Page 11)

Introduction
AOA/Pitot Probe and Heated AOA/Pitot Probe Installation Guide Rev. C 1-5
AIRFLOW: PRINCIPLES OF OPERATION
The concept behind Dynon's design is illustrated in the diagrams at right. The Dynon Avionics
AOA/Pitot probe performs two functions:
airspeed sensing and angle of attack
sensing. These functions require having
two pressure ports on the tip of the
probe. The normal pitot pressure port is
on the front face of the probe and is
designed to be insensitive to angle of
attack. The second pressure port is
located on an angled surface just under
the pitot port and is designed to be very
sensitive to AOA.
The pressure from each port is delivered
via separate pneumatic lines to the EFIS
unit or SkyView System’s ADAHRS
module(s). Those pressures are
compared to previously calibrated scenarios specific to that aircraft to calculate the current
angle of attack.
EASY INSTALLATION AND CALIBRATION
Unlike other AOA instruments available to homebuilders, the Dynon Avionics AOA/Pitot probes
do not require you to drill special ports in wing skins. It also does not have any moving parts
such as vanes. It is simply an AN5812-style pitot tube with an additional pressure port to
measure AOA. Simply use it as a normal pitot tube. The only difference is a second plumbing
line which runs back to the EFIS products or the SkyView SV-ADAHRS-200/201(s) for AOA
calculation.
Once installed, the AOA/Pitot is calibrated to the individual aircraft by performing a series of
pitch oscillations and stalls in various flight configurations. All calibration procedures are
performed via button pushes on the EFIS unit or SkyView display.
PRESENTATION
As shown on the right, angle of attack is displayed as a vertical
color-coded tape with

Red (down arrow at top)

Yellow (down / horizontal lines in middle)

Green (horizontal lines at bottom).
Once calibrated, critical angle of attack will be indicated with
the pointer positioned in the red area of the tape.
An audio alarm can also be generated as AOA becomes critical. It can be set as either a steady
tone that sounds very near the critical AOA, or alternatively as a progressive beeping tone that