In article . com,
"vlado" wrote:

Viperdoc wrote:
Beggs-Mueller does not work for all planes (although it does for Pitts'),
and some pilots do not necessarily believe in letting go of the stick for a
recovery, preferring to "fly" out of the spin.

What airplanes does this (Beggs-Mueller) not work for?

Cessna 150.
Note that the Christen Eagle and Pitts were the only acro aircraft
tested extensively. Limited testing was done with the C-150.
Gene Beggs did not have the time nor the money to carry out extensive
testing on popular GA trainers and cruisers.
This research was conducted in the early 1980's.