CO2 Canister Aerospike Rocket

As per the rules of the contest that this instructable is being entered in, My name is Matthew, and I go to Norwalk Highschool in Norwalk Ohio. The skill that I decided to pursue for the contest and for the year, is rocketry. I've always been interested in the idea of how rockets work and function, but I've never been able to pursue experimenting with them since my parents tend to not want me messing around with flammable materials. That obstacle is actually what lead to me deciding to try to find a solution with Fusion 360, and eventually I settled on making a rocket that didn't run off of flammable material, but one that runs off of CO2. Additionally, the reason that I chose to make an Aerospike specifically is because it's the only rocket nozzle I'm familiar with. I could've gone with a bell nozzle but I don't really understand how they work, and a don't feel like I'd have enough time to go that in depth on rocketry before the contest ends, so I just stuck with an Aerospike. Also, since I'm unfamiliar with the in depth functions of how to create weird shapes like an Aerospike in Fusion 360, I decided to learn how to use the line/curved line function in the sketch section of Fusion 360, it probably wasn't the easiest and most efficient way of doing it, but it works, so I went with it.

The only supplies you'll need to design it are a basic prior knowledge of how Fusion 360 works, which if you don't have, then I'm sure you can find somewhere on this website, it's the perfect place to look. Also you'll need access to fusion 360.

First, you'll need to draw this shape using lines and curved lines in the sketch feature, listed in the create category. I personally used the snap grid to figure out where everything went, which you can see where every point goes on the snap grid in the picture below. Once you've done so, hit the finish sketch button at the top right corner.

Next, you'll use the revolve tool , which is listed in the create category, on the previous sketch and revolve it 360 degrees around its' axis, which will be the line passing through the origin.

Then, you'll draw two circles of the dimensions 20mm. and 18mm., in the sketch feature, measured from the center of the bottom of the shape. You'll need to select the bottom of the shape, which is the flat disk, as the plane that you want to create the sketch on.

In this step, you'll extrude the space in between the two circles that you created in the previous step by 5mm. to create a ring like shape coming out of the bottom of the shape.

Then, you'll draw a rectangle from the center of the shape, all the way to the ring, with the dimensions of 9.5mm. wide by 1mm. long. The center of the 1mm. side must be on the origin so you've got to measure from 0.5mm. below the origin.

Next, you'll use the pattern tool, listed under the create category, still in the sketch feature, to create a circular pattern of 8 rectangles extending from the center. It should look like the picture listed below, for reference.

Now, you'll extrude the previous shape to -2mm. Once you select the object that you are going to extrude, since it's in the negatives and intersects the original shape, it will think that you're trying to make a cut, so make sure to select join in the little menu that pops up in the bottom right corner of you're screen.

Then, you'll create two more circles of the dimensions 7mm. and 10mm. in the sketch feature, still using the same plane as the original shape.

Now, still in the same sketch feature, you'll create a rectangle of the dimensions 6mm. long by 1mm. wide, stemming from the center of the circles, and then use another circular pattern on it to create 8 rectangles.

Next, you'll extrude only the sections of the ring that aren't intersected by the rectangles.

Then, you'll select the surface of the shape created in step 10 to create a sketch on. Make sure to use the plane that runs parallel to the original plane.

In this step, you'll draw two more circles of the dimensions 7mm. and 10mm. still on the plane from step 11, stretching out from the origin.

In this step, you'll extrude the ring that was drawn to -2.5mm with the extrude set to join.

Then, you'll draw two more circles of the dimensions 3.5mm. and 1.5mm. On the original plane.

Next, you'll create a circular pattern of a rectangle by the dimensions of 0.6mm. width by 1.75mm. length., but this time, only make it four rectangles instead of eight, still in the same sketch.

Now, you'll extrude the shapes in the picture by 4mm. the same way you did in step 10, extruding only the sections of the ring that aren't overlapped by the rectangles.

Then, you'll select the plane of the shape that you just extruded, the plane going parallel to the original plane.

In this step, you'll draw two circles by the dimensions of 1.5mm and 3.5mm. still on the new plane, extending from the origin.

In this step, you'll extrude the ring by -2mm. making sure to continue using the join feature.

Now, you'll select the outside ring for a sketch. The same ring created in step 4, select the plane parallel to the original plane.

Next, you'll draw two circles by the dimensions of 20mm. and 7mm. extending from the origin.

Now, you'll have to extrude the thicker ring by 2mm. This is that if you press in a CO2 canister, it doesn't leak all the gas.

Then, use the chamfer tool listed under the modify category to chamfer the inner edge of the ring that was extruded in step 22 by 1mm. This is so that it's easier to insert the CO2 canister.

Finally, you'll chamfer the outermost plane and edge of the tube like shape created in step 19 by 1mm. This is to make it easier for the tube to puncture the bit of foil keeping the CO2 canister pressurized. And with that, you should finally be finished designing a CO2 powered Aerospike!