The Mystery: How Boomerangs Work and Come Back Explained

[Fig Neutron]

What makes a boomerang come back when you through it?

My guess is that it has something to do with the shape, I'm just not sure what. I have found three boomerangs the fist one is a typical boomerang that looks kind of like this L., the second one is a disc, and the third one is kind of like a Y with the spokes evenly placed.

The first and third boomerang make the most sense. After looking at the first one I noticed that the edges were sloped which would make one side more aerodynamic. Since one side can move through the air faster that might make it turn or at least that's my theory. I am also guessing the same principle could work for the third boomerang?

The second boomerang is the one that is really confusing me. I have seen one that is a flat disc and others that just looks like a frisbee. I haven't tried the disc kind, is it possible that it is just how you through the frisbee? If so could it be like spinning a basket ball to make it bounce back?

I know I did a lot of guessing, maybe I got something right . Thanks

 

[A.T.]

I know I did a lot of guessing,

Have you done any googling?

 

[davenn]

What makes a boomerang come back when you through it?

Throw

Have you done any googling?

agreed

As some one who throws and even catches the returning boomerang, (apart from the aerodynamics) it's all in the flick of the wrist,
as in, if it isn't thrown properly, it won't return

kinda reminds me of this old Australian song ...

My Boomerang Won't Come Back - Charlie Drake

Dave

 

[Fig Neutron]

Throw

Well that’s embarrassing.

Ok, I just googled my question. I think I understand two of the kinds of boomerangs, but I’m still not sure about how you would make the disc kind come back. But, it’s just how you throw (got the spelling right this time) right?

 

[sophiecentaur]

What makes a boomerang come back when you through it?

I was told how it works but I forgot. It will probably come back to me, eventually.

 

[davenn]

I think I understand two of the kinds of boomerangs,

yes, there are really only 2 types of real boomerang. discs and three armed things are not real boomerangs

the 2 main categories are
1) sport/show ones that (when thrown correctly) will come back, generally 2 - 3 ft from tip to tip
2) hunting boomerangs, a lot smaller - usually less than 1.5ft, are generally designed not to come back, because if you are a good shot, you will down your kangaroo, emu or what ever other wild life you intend to eat.

boomerangs generally have both arms that are shaped like a plane wing
It's that flick of the wrist that puts spin into the motion of the boomerang

I have had a lot of giggles over the years teaching people to throw a boomerang correctly

 

[DaveC426913]

I think the very basic principle of a boomerang is simply that it angles itself upward, so that it simply starts to fall. But since its still aerodynamically stable, it slides sideways (along its plane) - which happens to be back to where it was thrown.

Ever thrown a frisbee up at, like, 30 degrees? It will reach its peak and start back down toward you - because it will only move along its plane. You can play catch with yourself.

Boomerangs do that, but better.

 

[DaveC426913]

I got a boomerang for Christmas when I was about 30.

I read the instructions on how to throw it. You're supposed to throw it toward the ground.

I did. It smashed into a million pieces.

 

[rcgldr]

I've seen similar results from L shaped, T shaped, Y shaped and triangle shaped boomerangs. The outside wing sees relatively faster airflow, so that results more lift on the outside than the inside, that causes the boomerang to curve. There is the issue of center of lift versus the center of mass. Typically the center of lift is somewhat in front of the center of mass, resulting in a pitch up torque that results in a roll reaction and with a typical overhand throw (outside edge upwards) used for boomerangs, the roll reaction reduces bank angle over time, perhaps beyond horizontal and banking the "other" way, resulting in a somewhat figure 8 pattern.

The cambered airfoil of a Frisbee tends to pitch down despite the center of lift versus center of mass, so a typical throw is underhand (outside edge downwards), so that the roll reaction again reduces bank angle over time. The entire Frisbee mostly acts as a single cambered airfoil, as the friction between Frisbee and air is low, so that the flow over the forward spinning surface doesn't produce significantly more lift than the backwards spinning surface (there's probably a small difference in flow detachment). The Frisbee curves based on the lean angle, not because of greater lift on the forwards spinning surface.

Aerobie flying rings have a special airfoil shape designed to move the center of lift close to the center of mass, eliminating any pitch torque from the air, which eliminates the tendency to roll. You need to "tune" them by flexing them a bit to get them to not roll. They're also thin, so they are good for achieving long distances.

 

[rsk]

In the days when frisbees were all the rage, I had something called a boom-a-ring, like a frisbee but a ring instead of a disc. It did always come back and, if I remember rightly, was best thrown just slightly upwards.
I might have a look to see if I can get something similar, see of any of my high schoolers can work our how it works.

 

[sophiecentaur]

I got a boomerang for Christmas when I was about 30.

I read the instructions on how to throw it. You're supposed to throw it toward the ground.

I did. It smashed into a million pieces.

You should have hung onto it. Antiques can fetch high prices these days.

 

[DaveC426913]

You should have hung onto it.

No. That probably would have severed my femoral artery.

Ba-zing.

 

[sophiecentaur]

One of my sons brought a boomerang back from a visit to Oz, many years ago, and gave it to my youngest son. We took it out on the downs with plenty of room for practice. I gave it a first serious throw (launch?) and it came down on a flint and shattered. 'You can't get the wood, you know.'

 

[OCR]

kinda reminds me of this old Australian song ...

Wouldn't you know it...?

After Charlie finally found the end of his yodel, he tripped again... only this time, he just bent his assegai. .

I'm not sure if Marylou ever came back, though... .

 

[sophiecentaur]

I believe that proper boomerangs are built with dihedral so they naturally do a bank turn. It's either dihedral or the sections of the two blades that produces more lift on one than on the other. PLEASE nobody bring Bernouli into this thread.

 

[sophiecentaur]

Not very well

Hope you feel better soon.