Sometimes using the wrong word is unimportant.  Sometimes it's deadly.  I have seen several postings in the last few days where the wrong word was used, and the message may be misinterpreted.

1)  Elevator bob weight -- In a 320 / 360, this is just aft of the baggage bulkhead.  It is connected to the idler in th pushrod linkage.  Its purpose is to increase the stick force per G.  It is not visible in flight.

2  Elevator counterweight -- This is mounted in the portion of the elevator which is forward of the hinge line.  It is not visible in flight either, but the front part of the elevator is visible.

Confusing the names of the above will not hurt you.

1)  BID -- a ply of bidirectional cloth.  I think this nickname came into vogue with the Vari-Eze, but I don't really know.

2)  One ply of uni -- a ply of unidirectional cloth

Confusing these two *can* kill you.  I have read recent postings where people are referring to plies of UNI as "BIDs".  Use bidirectional cloth where you are supposed to use unidirectional and your part will only be 50% strength in the direction that matters.  PLEASE don't say "BID" when you mean "plies of UNI".  Someone might misunderstand you and build an airplane that is not strong enough.  (Although I don't think that using BID on a canopy instead of UNI will actually cause a strctural failure.)

Picky?  Anal?  Guilty as charged.

- Rob Wolf