138VIDEO Boomerang Project Tour

In this video I want to give you an overview of the plans for making a

boomerang and that's what you see here. A couple of things to pay attention to. The

first is the grid that you see here. If you've never worked with a grid before

it's a way of transferring curved shapes from pieces of paper to pieces of wood

or any other material you might be working with. So you can start by

printing this file out. It's available as part of the course in PDF form and note

down here at the bottom it says one square equals half an inch. That means

that when you draw a grid of one half inch squares all over your piece of

quarter-inch plywood and then you look at this diagram and you transfer the

intersection points between the outline of the boomerang and the grid. You

transfer those points onto your wood and then connect the dots and you'll have

the outline you want. So down here for instance, right here the touch point with

the grid is right along this line and right along this line. So on your wood, on

your grid, put a dot there. Move over one, put another dot maybe 20% up from the

bottom. Move over here, another dot just to the right of this line here. You do

that all the way around and then like I said before you just connect the dots in

a smooth way as possible with a pencil and now you've got your

outline. Now in this project it's fairly small so another way to do it is just to

print out the piece of paper. Maybe enlarge it however big you want the

boomerang to be and then cut out the image, the outline, the profile of the

boomerang and glue that to your wood temporarily with some rubber cement and

then follow the paper and its outline to cut the shape and that works well. You

can peel off the paper and rub off the residue of rubber cement and you're good

to go. The exact size of the boomerang doesn't really matter much. It can be

this size or it can be larger. So this is one of those projects where it's kind of

flexible, easygoing sort of project. The overall size doesn't matter very much

What does matter very much is the airfoil shape of the arms of the

boomerang which really are wings. You need to think of them as wings. Two wings

attached together at 90 degrees. Look up here. You see this? This is the

profile, what I call the airfoil profile of the wing and the shape of this profile

creates lift because when the air hits the wing it has to speed up as it goes

over the top compared with other air that's going along the bottom and the

air on the top has to speed up because there's more surface area on the top of

the wing than the bottom. So that's really what causes lift in an airplane

wing or a boomerang wing. The thing is though you've got to get the whole

business of leading edge and trailing edge just right. See the leading edge

has to lead into the wind as the boomerang spins. So you can see here this

is the leading edge of this wing because the boomerang is thrown and it rotates

in a counterclockwise fashion. So counterclockwise means that this is the leading edge of the wing. This is the edge that's going to encounter the air

first and then this is the trailing edge. But look at here. Down here it's

opposite. The inside edge of this wing is the leading edge and this outer edge is

the trailing edge. So you got to get that right. The orientation on one wing is

different than the other and that's crucial because both leading edges, the

edges that encounter the wind as this thing is rotating through the air

counterclockwise, the leading edge has to hit the air first. So if you get that

wrong your boomerang is not going to fly very well, if at all. Now these lines here

they're not just for decoration. They're actually a huge help and it's a it's one

reason why you want to make something like this out of thin high-quality

plywood if possible. You see these these lines, these shaded lines correspond to

the plywood lamination lines that you're going to see if you've got the

boomerang shaped properly. So naturally just like contour lines on a map the

leading edge lines, plywood lamination lines are going to be fairly close

together because it's it's steep and blunt. But over here the trailing edge is

going to be much more shallow because it's tapered more. The beauty of this is

when you're shaping this boomerang you can really see how the contours are

going because of these lines. Now cutting out the outer perimeter of the

boomerang you're going to want to use some sort of a saw. So it could be a scroll saw, could be a band saw, could be a handheld jigsaw. Either of those will

cut curved shapes very well. So that's pretty straightforward. The rest of the

operation on the boomerang is done with a sander, a five inch random

orbit sander. So essentially that when you're looking at the at the boomerang

when it's first cut out the profile of the wing is just rectangular. And so by

using the sander you're going to create this blunt leading edge and more sanding

here is going to create the tapered trailing edge. And so as you sand these

lines the lamination lines become revealed more or less depending on the

shape you're imparting. So this is these lines you see here that's what you want

to see on your boomerang as you sand and as you finish. One other thing here in

the end I found that if you taper the underside of each wing your boomerang

is going to work better. I believe that's because it reduces the amount of

friction with the air on the end of the boomerang wings. But like I said it's on

the bottom face so we're looking at the top face we're looking at the curved face of the boomerang here but if we were to flip it over it would be an area

maybe in this zone that would be tapered on the underside and the same over here

an area about this size tapered on the underside and you can see that happening

here. One nice thing about these boomerangs is that they're pretty easy

to make. They're very safe to make especially the sanding part so it's a

great project for kids and when you're setting out to make them don't just make

one because most of the work is just getting things set up digging out the

saw getting the sander ready all the rest of it so make two or three or four

in one go. They fly very well you're going to need a large area to throw them

safely and they do hide incredibly well in the grass too so it's very easy to

lose them. I usually paint the ones I make red but yellow fluorescent orange

anything like that you'll want to paint it that color to give you every chance

possible to find these things after a throw