I made one of these a while back suprised me how hard I had to spin it to get a sound , good fun though
Mors made a few at the Moot this year and I've played with them before, they're fun and the results are directly in proportion to how much effort you put into swinging that baby about
how thick is it and is the cord nice and thin and getting nicely twisted?
I think the main sound comes when the roarer starts spinning on its axis whilst being twirled in the arc if that makes sence... . You need to 'wind it up' a little before it roars
I think I'll have a go at a heavier/bigger one and see how I get on.
Try making a giant bullroarer like this guy did RB. It sounds like he's got a lion purring somewhere