'Alternate' Stall Warning Systems

[BrasiliaCaptain]

Ladies and Gentlemen,

I'm doing some research on alternate stall warning systems for my Experimental Methods in Aerodynamics class.

I read the Roselawn American Eagle ATR-72 accident report, and it mentioned that Goodrich (I think) had researched, flight tested, and patented a stall warning system that detected stall via pressure measurement on top of the wing at the ~70% chord location. The research and testing was primarily done in the early 90s.

Does anyone know if any airplanes actually use an SWS like this? Does anyone have any inkling as to why more airplanes do not use this system?

Thanks!

[Shawn Coyle]

PM me for a complete description of the Airfoil Performance Monitor (APM), which is the device you're talking about.
It works by using high-speed sampling of the airflow and then looking for the ratio between steady-state airflow and turbulence. At the stall on a clean wing, the ratio of the two will be clearly defined, and the wing will stall at nearly that same ratio whether clean or contaminated.
Works on the takeoff roll above about 50-60 knots.
Tested on lots of different aircraft and wind tunnels and does exactly what we claim.