A PA28 does have an AOA indicator. It's called the AI (Attitude Indicator),
Final 3 Greens,
Whatever the attitude indicator measures, it certainly has nothing to do with relative airflow over the wings. It is not an angle of attack indicator.
we don't know why QDM needs the device, so there may be good reasons, although claibration will be interesting.
I've outlined it in several previous posts and calibration should be quite simple. The complicated bit in all this (for me) is going to be the small amount of pop-riveting required to assemble it and then getting it approved as a minor mod and any advice on this will be gratefully received.
QDM