Expert: Paul Soderman - 3/11/2004

Question
Hi,
I have a whole stack of questions, help with any of the following would be great, thanks!

I was reading that handling qualities deteriorates with a reduction in Short period oscillation (SPO) damping, what does it mean handling deteriorates?

What would reduce SPO damping?

How does static stabily influence handling?

What would you make a very large fin to cure a dutch roll problem?

what would reduce dutch roll damping?

what physical parameters influence slow spiral?

Thanks again,
Ray

Answer
Hi Ray - I studied aircraft stability and control in graduate school, but that was 40 years ago.  Here is what I remember.

1.  Handling quality refers to the response of the aircraft to pilot input and the workload required by the pilot to control the aircraft.

2.  SPO can be controlled by either aircraft design or countor moments induced by the control system.  I forget which aircraft design issues lead to SPO.

3.  Static stability is the steady-state stability of the aircraft.  If stability is too strong, it can be hard for the pilot and control system to maneuver the airplane.  It flys like a rock.

4.  I have forgotten the parameters affecting dutch roll and spiral.  I suggest a web search or finding  a book on aircraft stability and control.  This is a graduate level subject, but the phenomenon you mention are quite common in aircraft design and are discussed.  I lost my book, sorry.

Paul