In a previous
thread about noisemakers in the woods I suggested a
bullroarer based on what I've read about them. I figured I'd better be able to back up my statements about how easy they are to make, so I tried making some.
Executive summery: tiring to use, tricky to make without practice and mine were not overly loud.
These were carved from freshly cut (I was removing the tree from my backyard) maple. I cut the branches with a saw then split out one slab using a cheap tomahawk and the other using a Cold Steel 18" Bowie machete. They were then shaped using the Mora knife (4.5" blade). The tether was a cheap piece of Walmart "paracord".
The hardest part was cutting a good, thin, flat slab. It took me close to a dozen tries before I finally split one properly. Maybe it was the green wood, maybe it was the choice of tools, maybe I just suck at splitting flat 1/2" slabs. If thicker than 1/2" it takes way too long to carve the required airfoil shape.
Once a good slab was cut the rest of the carving took less than an hour, including drilling the hole (SWK awl). These were not sanded smooth though they are supposed to be.
Tested in their rough conditions, they did make a weird buzz/hum sort of noise but it did not seem very loud. Though it did cause my neighbor to peek over the fence. Swinging the bullroarer was surprisingly tiring and the rope created and then tore open a blister on my finger where it rubbed while being swung. Leather gloves would be needed.
So, my opinion? A properly-made one may be able to send messages quite a ways, but a hack job by some guy in the woods just wastes time, burns up precious calories, and damages the hand. I hereby
retract my suggestion about making/using a bullroarer as an emergency signal.
-Blast