Sling-O-Plane: V.1.0 - Instructables Launch It! Challenge Entry

About: I like to build, create, and invent new things to use in life. Sometimes I like to share them with others, that's why I joined Instructables. :-)
Welcome to the Sling-O-Plane project.

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

Potential hazards

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 :
-- Scissors
-- 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

Here are the materials and tools used to accomplish this project.

We used:
(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

This is a pretty simple step here.

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

After racking my brain for household items that we could use as a sling I came across the Piano-wire Slingshot by chluaid right here on It is also in the launch it challange and is a great project.

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

In this step we made a catch. I call it a catch because I am not sure what else to call it..

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.

Time for the launch, but first safety. Considering there is no noise, we end up not using ear plugs. We also don't use any helmets, my kids heads are pretty hard (they get that from their mother). I figure that if this plane hits you in the head the plane will break but that's about it. However as I always say "Use eye protection" even foam hitting you in the eye will at least hurt. Lets not forget about the metal catch or the sling breaking. We are all wearing eye protection, my kids are wearing clear safety glasses so they are hard to see in the video but they are wearing 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

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

At this step I want to review the lessons we have learned from this project.

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.



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    25 Discussions

    Mr. Rig Itthe gizmoman

    Reply 11 years ago on Introduction

    Thank you for your comments. I'm planning a version 2.0 sling-o-plane. It is going to be with the bigger plane, thank you for the link. I will probably just buy the one at Hobby Lobby, thing is pretty darn big, it might be the same one that you have shown. Yeah I could have taken it through the fuselage and glued the catch down. I thought it would rip right through the foam from the stress of the launch. I got about 20 launches before it finally came out during a launch. The left rear horizontal stabilizer finally ripped off at one point during a failed launch. Version 3.0 will have rocket motors that will engage after it leaves the sling. I just wonder if it will melt on the way up... :)

    Way to go... nice project. I myself used to build them when I was around 10 years old :)  I have some easy mods to try out:
    1)  Try fitting on one of those small 3 volt electric motor you find in any broken toy laying around and a reasonable well-balanced propeller. I usually used a lightweight main rotor from my broken indoor helicopter but basically anything will do. Fit the prop to the motor directly on the shaft in a pusher configuration (the reson being nose landings: you want the spinning propeller to be as far as possible from impact point) and make sure the motor is not too stressed by the propeller. (Assuming the aircraft is a foamie) drill the airplane from behind and allow the motor to seat comfortably. Pass the wires through and make space for 2 pencil batteries in the forward section of the fuselage to balance the plane out. A good battery holder is one of those used torches which have an included switch. If you can dig in from underneath it will be still streamlined but the batterholder and switch will be easily accessible. Make sure the loaded aircraft is almost balanced by trying to hold it from 1/3 the width of the wing where the camber is. Preferibly the aircraft should be just a little nose-heavy and then correct it by pushing the elevators up. The reason is when the aircraft is going too fast, the airstream would take over and the aircraft climbs but when the aircraft has climbed and slows down the loss of airflow-force the nose starts tilting down and the glider starts gaining speed. This configuration will not make the aircraft sustain it's flight since the motor is not powerful enough but will definately increase flight-time because of increase in power and inertia :D

    2) For launches: The aircraft should be between 15 and 35 degrees. The shallower the angle, the more fluent the flight but will fly lower and land earlier but smoother.

    3) Just take care with the rockets, they are far more dangerous!


    the gizmomanMr. Rig It

    Reply 11 years ago on Introduction

    no if you put something like that aluminum tape to deflect the heat off the body and you dont have to sling it into the air if you use rockets to propel it


    heres the largest manufactured foam glider you can bye (big isnt it)

    Mr. Rig Itthe gizmoman

    Reply 11 years ago on Introduction

    It's a U2 Spyplane! yeah that is big. Now you got me really thinking. I will have to use some of the others as X-planes before I go that big. I have been thinking/designing all night about mounting the rocket motors. The Hobby lobby was closed today or I would have bought the big plane and sling launched it. So I just went to Michaels instead and checked out what they had (no foam planes). Did have the rocket motors though. Hmmm. the bigger the rocket motor the better? Or will it just rip the wings off? I may just have to figure out the math on all this and/or build a plane from scratch. I am thinking X prize; sling launch it and when it gets up in the air engage the motors. This way it doesn't spend half its energy getting up. Thank you for the link, what a great idea!

    apburnerMr. Rig It

    Reply 10 years ago on Introduction

    First let me congratulate you are your kids and you taking an interest in them. Anyone man can be a father but it takes a real man to be a Daddy. Anyway I see that the thread has entered rocketry's realm. This is where I has some knowledge. A few years ago I was a member of Tripoli and was certified level 2 high power. Anyway. I had remembered that aerotech had at one time made special motors for gliders and so I searched and found the following links. These motors are reloads and as such you must buy the reusable hardware also. they are designed with a low thrust and long power curve. If you have not worked with rocket motors then let me explain the designation. The Letter is a range of total power in Newton/Seconds and each letter is a doubling of the power. So an
    A = 2.5n/s Maximum
    B = 5.0n/s Maximum
    C = 10 n/s Maximum
    D = 20 n/s Maximum
    E = 40 n/s Maximum

    The number is the average thrust in Newtons. So the first motor in my link is a D-7 the maximum power is 20 n/s and the thrust is 7 newtons for just under 3 seconds. A newton of thrust can be converted to a pound by dividing it by 4.45. So our example of a D-7 would have an average thrust of 1.75 lb for 3 seconds. I hope this will help you with you trials on a rocket assisted glider and I do recommend the reloadables because one - you get more motors for your money over the long haul and two - you have many more choices with the reloadables.

    where to buy hardware

    Motor reloads

    Aerotech 24mm motor hardware

    apburnerMr. Rig It

    Reply 10 years ago on Introduction

    You may also wish to use surgical tubing to make the slings. That is what RC glider enthusiasts us. their slings are a bit too long for your uses but I think that a well stocked hobby shop should sell the tubing by the foot. And the is no other rubber band that will touch that stuff. Just go to a hobby shop that has a big supple of RC planes and the like and start asking questions and tell them what you intend to do. They should be happy to help. Steve

    apburnerMr. Rig It

    Reply 10 years ago on Introduction

    Hey no problem. Been watching for when I could help. And when this thread started it was a natural. Glad I could help. Steve

    the gizmomanMr. Rig It

    Reply 11 years ago on Introduction

    if you are puting the rockets on the wing put as close to the fuselage as posible and get those diy rockets for the motor mounts wich you glue to the airplane( this way you can take the spent motors out & yet get the strenth needed to keep the motors from shooting off the airplane)you can order just the motor mounts


    10 years ago on Introduction

    Ummm. no offense but that is slightly boring... i put a 2000 rpm engine in mine and turned it into a rc glider by dremeling it to fit servos and a receiver, and, of course, the engine. :P

    2 replies
    Cubie2Mr. Rig It

    Reply 10 years ago on Introduction

    Yeah I guess so... Still fun though!!! (Thos gliders are pretty cheap I landed mine corectley AND I still managed to break it in half. :P


    11 years ago on Introduction

    really like it had a plane like that bad part car couldnt stop in time so it went bye bye lol

    the gizmoman

    11 years ago on Step 8

    the legs on the catch or hook as i call it(the two ends that are in the fuselage)could be longer as in almost through the fuselage. then glue the wire that runs parallel to the fuselage for additional strength