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Old 15th Nov 2015, 10:06
  #48 (permalink)  
safetypee
 
Join Date: Dec 2002
Location: UK
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Sooty,
With fading memory the AP should disengage at stick shake, not at ‘stall’ (stick push). The use of the AP (autotrim) at low speed in the 125 may be of greater importance because of the ‘short coupled’ design. This implies that more tail up-trim could be applied which detracts from stall recovery.
Planned stall tests should limit the start trim condition to 1.3 Vs (similar to Vref, i.e. a margin ~ 30kts), stick shake is nearer 1.1 VS (~ 10kts). The difference is like having to fly normally with the aircraft out of trim by 20 kts.

Iron … its not for me to defend a reputation, but inaccuracy demands comment – pickled not preservation.
In the heat of war, having building a wooded aircraft with higher capability than most others, who worries about the sensitivity of a stall.
Ground 'stalls' are linked to the aircraft configuration – tail arm and elevator effectiveness.
The DH110 was a structural failure (rolling g), not flutter.
The Trident is a classic example as why the operator should not be allowed to ‘design’ an aircraft.
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