Thanks Max!

Conceptually that's really helpful, but now the .update() method returns nothing usable. so I tried:

var objectlist = FactoryAirfoil.calculate().getCurves(); // should return an objectlist of curve items within the objectlist returned by the .calculate???
for (var i=0; i<objectlist.length; i++) objectstojoin.addObject(objectlist.item(i));

Now no error is thrown - but also there is no output - but I'm in a rush.

Will have time to look into it later today.

Cheers,
Hamish