Okay, so it's not exactly a weapon (but it could easily be used as one, to vicious effect probably). It is however another very cool piece of primitive technology.

What it is: A length of cord tied to one end of a piece of wood (or something else) carved into one of any aerofoil shape.

http://9waysmysteryschool.tripod.com/sitebuildercontent/sitebuilderpictures/bullroar.jpg

What it does: When swung, makes a gargantuan sound that works on the doppler effect and varies in pitch relatively with speed. It's been used by various world peoples for ritual use and, in an inventive system, to communicate the long distance across villages and camps easily.

I found a short video of some bushcraft guy illustrating the build and the use:

http://www.youtube.com/watch?v=Wf-FgFSdrhI

What say you? If you have some woodworking skill (I have next to none) it probably wouldn't be too difficult to make a nice one. I've never heard one in person but supposedly they are very loud.

I've heard a plastic one before. The one I heard had a very low/deep humming sound that could be heard from 50 feet away, which was pretty good as it was in a pretty loud area (Historical Exhibit). I would imagine that a wolf whistle would be louder and easier to get a sound from, but then again I haven't heard a full sized wooden one before, so I can't give a comparison.

I would think it's pretty easy to carve, as far as carvable things go.

You don't need any woodcarving skills to make a basic one... I made one with a plastic ruler and some shoelace. The sound was not soooo great, but it gave you an idea of how loud a nice heavy one with sharp edge can be.

I've made diamond shaped ones that put out a great sound. Longer cords work well, so you can pick up some speed, too.

An ordinary shoe horn works well. Even a wooden spoon will work but they are a bit light.

I remember reading about these as a kid and making one from a slat from the old wooden window blinds...
Made a fine racket!
I just picked up a book on the "origins of ordinary things" and some are quite enlightening...  For instance, the hula hoop, popular when I was a teen, was known in ancient Sumer...

There was a huge fad for hoop-twirling exactly as we did in the 50s back in 1800s England.  The hoops were made of wood, of course, and physicians at the time described exactly the same sorts of injuries and maladies that contemporary hula-hoopers complained of.

Growing up, some of the kids we would run with lived in a local pueblo/reservation in NM. We used to make these but I remember using cedar and that they were groved on the sides. I'm going to have to ask my dad because he made some for us too. Anyway we would tie a long rope about 1/4 to 3/8 in. in diameter and as you got momentum, you would let out more rope until you had a wide arc. Hearing these, whether one or more from a distance was kind of an eerie sound.

I've made two of these. They work great. The edge has to be very sharp all around. The string is also very important for it to work properly and needs to be very thin but strong. You need to use the densest and heaviest wood possible. Good luck to anyone who is going to make one!

I guess ceramic could work too..It would be heavier than most if not all woods,easy to make..i gonna try it.

Got 2 Australian bullroarers at home.
One in a heavy wood, the other one in light plywood.
Both sound good.
Though I don't "fly" them often as I'm scared of the accident ! (already broke a few ropes, but got lucky each time : no injury)
Indeed, the spinning movement puts the rope in harsh conditions : twisting on one side, then untwisting to twist on the other.
Any rope that is made by twisting several thinner ropes in a spiral twisting way are not good : they would unravel and be dangerous !
I've tried a leather rope, but leather does not resist to tension nor twisting too much, and it broke very rapidly.
I've been trying to find out in which material traditional Aboriginal bull-roarer were, but without success.
They often use ropes made of their own hair, but that's by applying a twist, so I guess it wouldn't be good for the bull-roarer.
Maybe kangaroo's sinew ? This should be able to twist and untwist without breaking... but wouldn't be long enough.
I guess a modern "criss-crossed" rope could work well, as a paracord for instance (but that seems too thick though).
Any clues ?

Try using the braid from this sling reconstruction. It makes a kernmantle rope like paracord, and you can control the thickness because you're making it.

or just use paracord  ;)

Got an australian tourist model around somewhere.
Works :-)

Crocodile dundee used one in the second film :-)

I've never seen one of these before, but now I know what I want to make next time I go camping ;D

I made a clay one,that needs to be fired..although at the first hit at the ground or something it would surely break. Also i made one from beech wood as it's heavy,and it has the usual elongated oval shape.It measures 30x4.5cm,tested it and it sounds like others i've heard\seen on YT.It can be heard from 300m but,today.i'll test it more from long range...
Also i've seen bullroarers that have like teeth..do they sound better,more far because of the increased line of edge? What would be the one that sounds the farthest?

jlasud wrote on Mar 24^th, 2012 at 1:52am:

Also i've seen bullroarers that have like teeth..do they sound better,more far because of the increased line of edge? What would be the one that sounds the farthest?

Good question !
Are these teeth to increase the sound ? Or to make it a multi-tool (bullroarer + saw) ? Or both ?
Have any picts that could give us a clue ?

Also I'd like to add to the topic that it's possible to make very easily a whistling bull-roarer by just attaching a segment of bamboo to a rope, and giving it (the bamboo) a straight vertical cut acting like a long fipple.  When it turns around itself, the wind gets "cut" by the fipple and whistles !

And another very easy way to make yet another type of bull-roarer-like instrument : by just cutting and spining around your head a 1.5m of a plastic ringed pipe of this type :
http://www.achat-aquarium.fr/administrer/upload/080706_162213_ek_NjUew2.jpg.jpg
Not exactly the same sound-generating phenomenon though : Air inside gets caught in mini vortexes due to the rings and create a nice whistling.  By accelerating/decelerating the spinning, you can reach all the harmonic components of the basic pitch... and you can even just put it in your mouth and blow, works the same.

All of my bullroarers have had problems with the sound cutting out after a few seconds when too much twist builds up in the cord (shoelace).  Maybe a heavy duty fishing swivel would help?

The twisting of the cord is what makes the bullroarer spin one side, then slow down and spin back the other side.
Had the idea of using a fishing swivel but never tested it for real.
If you do, let us know how it works !

http://www.youtube.com/watch?v=3Kf_RYVt2XQ&feature=related
;D

ROFL !  ;D :D ;D
At first I was wondering how it was possible to have an Aboriginal man bull-roaring in front of both a camera and his wife...
Then, ok, it's an advert !
The bull-roarer is one of the most powerful and secret-sacred object amongst the Aboriginal people (along with the lethal pointing-bones).
It is exclusively possessed, used and even seen by initiated men of high degree.
Using it as a "bush telephone" is a legend (same goes with the didgeridoo).
It was mainly used during initiation ceremonies, at night, after having told frightening stories to the young men in initiation and leaving them in the darkness alone... it was supposed to be the voice of a dreadful spirit, meant to make them sh!t in their pants (or loincloth).
But it was (is) not only a lure but was (is) also believed to really be animated by a higher force/spirit.
It may be compared to a telephone, but not for man-to-man communication, rather for man-to-spiritworld.

@Jau...  ;D Now that is too funny  ;D

Wow. I remember these.
I made one in Cub Scouts.
Or rather, I tried to make one.
After splitting two cedar blanks I finially just ran a kite string through the hole.
It made some noise but not very loud.

Hmmm, I'm thinking that a thin board like 8" x 4" x 1/8" would make the best sound.
Spruce is used in musical instruments for it's resonants so maybe I'll try making one out of spruce.
Air resistance wouldn't let you swing a very large one but an additional weight coming off the outter end could help swing it better.

 Where your cord will fray is where it runs through the hole, so I would be sure to round off the edges of the hole.  I have never made one but am planning on soon, then I came across this thread.  I have heard they need to be thin and preferably a hardwood for the weight.  
  If you are having trouble with your cordage untwisting use a braided cord, either a 3 strand or a 4 strand, you may be surprised and find a flat braid works good, it would twist up and untwist.

 Here are some bullroarers in the north american ethnographic collection.
http://anthro.amnh.org/north

Paint stirring sticks and what ever string
Lots of fun at a camp out after everyone has gone to bec