This question has come up last year. SASless gave me a response which explains the situation.
Re: TH55 Tuck Under Habit.
quote:
ATPMBA wrote on 17th July 2002 20:43:
Please tell me more about this tuck under habit. How do you get into it ? Full left pedal at the start of the autorotation ? I've been flying S300C's for the last four years and this is the first of heard of this. Is that canopy slat suppose to fix the problem ?
Thanks.
My information is dated....however your statement is correct. The slat overhead the canopy was a fix to help correct the tendency for that little rascal to tuck its nose upon entering autorotation. That was really exaggerated if the student got confused with his tootsies and tromped on the left pedal. At one time the TH-55A was actually flown without the slat and its handling qualities were noticeable the worse for it in those maneuvers. I also think the tucking desire was also enhanced by low rotor rpm as well.....
My real memories of flying the aircraft was that it was very sensitive in pitch and yaw and thus either way, a tucking moment could be induced.....excessive yaw will give a rolling and nose down pitching as well as just being sensitive in pitch. The slat acts as "drag" and would tend to hold the nose up as I recall.
Go to verticalreference.com and ask for some old time Fort Rucker Flight Instructors about this.....some of them who flew the aircraft there at Rucker might be able to better answer your question.