Noob, I am.  I created an airfoil using polylines and circles. Saved in separate file.  I then input the airfoil to my main drawing as a block. In the main drawing I choose to explode the airfoil so I can manipulate the block for this specific application.  Poof! The block disappears.  This behavior gives me the opinion that I am not doing something right, perhaps even at the beginning, when I created the airfoil.  BTW, an example of what I'm trying to do is an offset to the airfoil's outline. 

I also noted that while trying to figure this out, that I can't delete block references from my main drawing.  After inserting the block once, I am not allowed to reinsert the same block name again, even though the block is not seen on the main drawing.  I had to rename my block drawing to bring it in.  In the references palette, there are no file names of the blocks, I unattached them and unloaded them, yet the program says they are still there. This may be due to the fact that I had originally brought these airfoils in as a reference drawing, not as a block.