Stability Wars: Why Did Relaxed Lose?
Join Date: Mar 2005
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Wow, you see? Airbus is much simpler! Except you need all those protections and such...
The "second mode of oscillation" is something I must have read in the "aerodynamics for naval aviators" or some similar old book. I think it is the short period, yes.
Yesterday I saw pictures of a Bombardier CS-100 series, and I noticed they have sidesticks. I assume they have a fbw flight control system. I wonder of what type. I would bet for a C* type, but it could be a C*U if it included a trim switch and some stick forces to protect from departing from the envelope.
The "second mode of oscillation" is something I must have read in the "aerodynamics for naval aviators" or some similar old book. I think it is the short period, yes.
Yesterday I saw pictures of a Bombardier CS-100 series, and I noticed they have sidesticks. I assume they have a fbw flight control system. I wonder of what type. I would bet for a C* type, but it could be a C*U if it included a trim switch and some stick forces to protect from departing from the envelope.
Join Date: Sep 1998
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As this old thread was referenced in a new one I thought I might add some info.
CSeries is C*U in normal mode. The pitch trim switches are used (inflight) to set the speed reference and a bug is shown on the speed tape.
We do a little exercise in the sim to demonstrated the U function by inducing a speed differential and watching the thing attempt to recover to equilibrium. A couple of oscillations only then the pilot intervenes and recovers much faster than the FBW. Life is too short to watch it do the whole thing.
It's pretty impressive though if you abuse the aircraft and then let go. Assuming you have enough height to play with.
One interesting anomaly is the tuning between AT and FBW. The engines at Higher altitudes are VERY slow to accelerate/decelerate and it's possible for the two systems to become unsynchronised.
CSeries is C*U in normal mode. The pitch trim switches are used (inflight) to set the speed reference and a bug is shown on the speed tape.
We do a little exercise in the sim to demonstrated the U function by inducing a speed differential and watching the thing attempt to recover to equilibrium. A couple of oscillations only then the pilot intervenes and recovers much faster than the FBW. Life is too short to watch it do the whole thing.
It's pretty impressive though if you abuse the aircraft and then let go. Assuming you have enough height to play with.
One interesting anomaly is the tuning between AT and FBW. The engines at Higher altitudes are VERY slow to accelerate/decelerate and it's possible for the two systems to become unsynchronised.
