I just thought of a better analogy. The goal of almost any aeronautical engineer is to build a plane that has good positive stability; you let go the stick and it reverts to stable, level flight. The reality of the power system more resembles the V22 Osprey, or the Shuttle 'flying' on final approach. One minor wrong move and you soon become a pile of burning composite on the ground. Both "fly" at all because they have significant flight control hardware+software to ..mimic.. that stability. But mimic is the best as you can get. Newer, better mimickry is still mimickry. -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433