In this instructable Ryan (age 8) and Holly (age 11) and Dad ( age Nunya) build a giant sling and Styrofoam plane. The objective: To launch this plane as far and high as we can with our homemade GIANT slingshot and have fun doing it. We have dubbed it the "Sling-O-Plane Project".
You will actually find 2 Instructables within this one project. The reason being, one we had to build the plane (and other plane parts) and, two we had to find something cheap and reliable to use as a sling.
There is something you should know before starting. This project was for my kids so they could participate in the contest, they could get more interested in science, and so we could just have some fun together. There are no high tech gadgets here, this on a younger level so positive reinforcing comments and suggestions are welcome, and yes the kids are reading what you have to say.
There are several videos of various launches for this project, most are successful some are not. Also the video quality is not all that high. My daughter just got a digital camera for her birthday so we are learning to use it still. We do hope you enjoy what we have accomplished.
If you have suggestions on how we can make this better please post them.
Step 1: Safety Briefing
There are only a couple of serious hazards to consider with this project
1. Use eye protection when handling the following sharp tools and other materials such as :
-- Safety wire
-- Elemers glue -Nontoxic, but you don't want it in your eyes.
My kids and I wore safety glasses, you can't see them in the videos though, but they were on.
2. Flying debris - the actual plane itself or the "metal catch" could damage your eyes if you were struck by either one. Flying debris also consists of the actual sling breaking and snapping back. That would hurt so bad if it hit you in the eye and could blind you. My eyes are watering just thinking about how bad it would hurt.
3. Heat - Here in Arizona the temp can get up to 110-115 make sure you don't over heat yourself and drink lots of water. It was about 90 degrees outside when we conducted the launches, so we were ok.
Step 2: Materails
(1) Turbojet 200 Glider
(1) 16 inch bicycle tire inner tube
(1) .30 inch safety wire (Left over from Dads time in the Air Force)
(1) Bottle of carpenters wood glue
(1) Pair Sharp Scissors
(1) Acid Brush
(1) Pair of needle nose pliers
(1) Pair duckbill pliers
Step 3: Assembling the Plane
We needed to make sure that the plane would hold together . these planes tend to fly apart under stress. Gluing the parts together was really the only answer. I would have used "Gorilla Glue" but mine dried up, I would have also used my Elmers Blue Poly Glue if I could have found it. So Elmers carpenter wood glue was what I had to work with. I wasn't sure if it would hold to the foam but it did.
We applied the glue using an acid brush. First we started with the fuselage wing area and gave it a good coat of glue. It slid right in without a fuss.
Next we installed the horizontal stabilizer. We painted glue down the center of the stabilizer and it slid right into the fuselage. We only had to wipe off a small portion of glue there really was no mess.
Airplane parts You can go to NASA's web page for an identification chart of aircraft parts.
Step 4: The Sling
What I was actually looking for was how to make a proper braid and braid some rubber bands. When I saw chluaid's project it looked like to much work to braid small rubber bands. So i thought on a bigger scale.
We came up with the idea of using a bike tire inner tube. It just so happed that there was a brand new 16 inch tube in the garage. The kids don't have 16 inch tires anymore because they grew out of those bikes, so we were good to go.
Make the sling
1. Using the scissors I cut the stem from the tube.
2. Next I sliced the tube open so I could cut long pieces.
3. Then I decided that we needed thin strips to work with, maybe something a little wider than the size of a rubber band . So I started cutting thin strips they came out to about 1/4 of an inch wide.
4. Soon I had the materials that I needed.
I did end up braiding 3 strips together, making a very nice weave. The result was a very strong rubber rope, only it was really to short to use and again I didn't have the time to weave 3 or 4 rubber ropes to make the long sling we needed.
So I had to go with the single cuts that I had made. I used a basic fly fishing knot
(Surgeon's Knot) to secure 2 rubber strips together.
Watch the sling video below the text; you will see where the knot was tied, and also where I mounted the sling. There are also some pictures below the video.
We have to have something on the plane to attach to the sling so now we are ready to move on and make the modification to our aircraft.
Step 5: The Catch
1. Using my two sets pliers we cut off about and 8 inch piece of safety wire.
2. Next we used the needle nose pliers, bent the wire in half and then began to twist the safety wire around one tip on the pliers.
3. We use the duckbill pliers to twist the safety wire in a braid.
4. We made about a 2 inch braid with long legs.
5. Next we cut off the remaining wire leaving about 2 inch legs. Then we made and arch in each leg about the size of a quarter. See the pictures below for a better understanding.
6. Finally we bent the head to a 90 degree angle opposite of the legs.
7. After reviewing the structure of the fuselage placement of the the is decided we just have to insert it now.
8. Measure where you want the catch to actually rest, then bring the tip of the legs to very rear of the spot and insert them, using light pressure, in to the under side/belly of the plane. We stuck close with our quarter size because that is how deep we wanted the legs in the Styrofoam. This will help keep the legs from ripping up the body of the plane.
9 Last thing to do is find a place to hook up the sling and launch it.
Step 6: Launch It.
Lets do it.
Ryan's launch is first,
Then Holly's launch,
Then Dads launch,
Then Ryan tries again and does better.
Step 7: Trials and Failures
You will see in these videos the plane does fail to launch. However the failures are due to operator error. Take a look at the last one and you will hear my daughter laughing at me.
Step 8: Lessons Learned
1. The Elmers wood glue worked at holding the plane together, I was surprised.
2. The catch did begin to rip the Styrofoam from the pressure release but the damage wasn't bad. I can probably touch up the damaged area with my Elmer's poly glue 9if I can find it) and it should be fine.
3. The bicycle inner tube worked great as a sling, I was slightly unsure of its how it would perform. I haven't used my new rubber rope yet If I make a couple more and can weave them together that would make one sweet and powerful sling.
4. The plane ended up flying about 60-70 feet. I was disappointed in its performance, but what do you get for $3.50? The design of the wings of the plan aren't really true airfoils, the were completely flat on the bottom. It they were at least a little rounded we would have gotten better lift and would have flown farther. I am considering the larger plane they have at Hobby Lobby. We may get it and try again.