Mathematically speaking, this particular flying object shouldn’t be able to fly.  What do you think about that?

Why can this thing fly? It doesn’t even LOOK like a plane! When I teach at the university, this is the plane that mathematically isn’t supposed to be able to fly! There are endless variations to this project—you can change the number of loops and the size of loops, you can tape two of these together, or you can make a whole pyramid of them. Just be sure to have fun!

It’s actually a bit complicated to explain how this thing flies when “mathematically” it isn’t supposed to, but here goes: there are FOUR forces at work with your flying machine. Gravity is always pulling it down, but air pressure keeps it up (called lift). The way real airplane wings generate lift is by having a curved surface on the top which decreases the air pressure, and since higher pressure pushes, the wing generates lift by moving through the air. (If this idea doesn’t make sense, be sure to watch this video first!)

Ok, but what about a flat wing?

If you drop a regular sheet of paper, it flutters to the ground. If you wad it up first, you’ll find it falls much faster. The air under the falling paper needs to get out of the way as gravity pulls the paper, which is a lot easier when the paper is wadded into a ball.

For a flat wing (like on a paper airplane) to glide through the air, it needs to be balanced between gravity and the air resistance holding it up. In order for a glider to fly, the center of pressure needs to be behind the center of gravity (learn more about center of pressure and center of gravity in the third video below). By adding paper clips to your paper airplane, you move the center of gravity and center of pressure around to find the perfect balance.

When designing airplanes, engineers pay attention to details, such as the position of two important points: the center of gravity and the center of pressure (also called the center of lift). On an airplane, if the center of gravity and center of pressure points are reversed, the aircraft’s flight is unstable and it will somersault into chaos. The same is true for rockets and missiles!

Let’s find the center of gravity on your airplane. Grab your flying machine and sharpened pencil. You can find the ‘center of gravity’ by balancing your airplane on the tip of a pencil. Label this point “CG” for Center of Gravity.

Materials:

• sheet of paper
• hair dryer
• pencil with a sharp tip

We’re going to make a paper airplane first, and then do a couple of wind tunnel tests on it.

For the project, all you need is a sheet of paper and five minutes… this is one my favorite fliers that we make with our students!

Find the Center of Pressure (CP) by doing the opposite: Using a blow-dryer set to low-heat so you don’t scorch your airplane, blast a jet of air up toward the ceiling. Put your airplane in the air jet and, using a pencil tip on the top side of your plane, find the point at which the airplane balances while in the airstream. Label this point “CP” for Center of Pressure. (Which one is closest to the nose?)

Besides paying attention to the CG and CP points, aeronautical engineers need to figure out the static and dynamic stability of an airplane, which is a complicated way of determining whether it will fly straight or oscillate out of control during flight. Think of a real airplane and pretend you’ve got one balanced on your finger. Where does it balance? Airplanes typically balance around the wings (the CG point). Ever wonder why the engines are at the front of small airplanes? The engine is the heaviest part of the plane, and engineers use this weight for balance, because the tail (elevator) is actually an upside-down wing that pushes the tail section down during flight.

When we use math to add up the forces (the pull of gravity would be the weight, for example), it works out that there isn’t enough lift generated by thrust to overcome the weight and drag. When I say, “mathematically speaking…” I mean that the numbers don’t work out quite right. When this happens in science for real scientists, it usually means that they don’t fully understand something yet. There are a number of ‘unsolved’ mysteries still in science.. maybe you’ll be able to help us figure them out?

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### 127 Responses to “Flying Contraptions”

1. It was the way it was modeled on paper using math that made it impossible. 🙂

2. Cheyenne Shaw says:

Take it a step further:
Try experiment with flex straw and see what happens (redirection of flight)

Question:
If mathematically impossible to fly, how is this helicopter able to take flight? What causes it to fly without wings?

3. Cheyenne Shaw says:

This was great to create paper helicopters, then do an experiment comparing the distance traveled between the helicopter and a paper airplane. The kids got a kick out of testing their hypothesis, recording data, and developing charts to determine the average distance.

4. Suzanne Schmitz says:

“That was fun! Can we do another one?” is what my 9 year old son said!

6. Tricia Kruchten says:

7. EJ & Anika Byers says:

We had problems unless we threw our planes very SOFTLY. Our record was 33 feet and 2.5 inches! Thanks – this was really fun!

8. Try it and see! If the paper is too flimsy, try doubling it up so it will hold its shape better. Construction paper is usually 64-76 pound weight, and index cards are 90-100, so index cards tend to be stiffer, and the texture is such that they fold a crease better (if needed).

9. kelly christian says:

Can you use costruction paper instead of an index card?

10. Put two side by side on the table and tape the rings together so they look like a figure 8 laying sideways. Now stack the third on top so the circles look like a triangle with the third laying on top of the side-lying figure 8.

11. Shiralee Seerden says:

this is my first time and i have done 4 rings but i do not know how to make a pyramid.

12. Lorena Wood says:

amazing ! I have to say I did doubt you but now I am amazed my airplane[ with no wings ] flew.thank you

kristine [ daughter of Lorena]

13. Tawnee Hinton says:

This was our first experience and my daughter (8yo) LOVED it. She was beaming being able to do her own experiment by herself and then watching it fly, she was jumping up and down. Thanks. Can’t wait to try another one soon.

14. Christophe Landa says:

Thanks!

-Jasmine

15. I am putting together an entire rocketry lab that will be released in summer… look for it soon!

16. Christophe Landa says:

-Jasmine (4th)

17. Hannah Strickland says:

Hi –
We had fun with this one, but one question was: does this work like the dyson circle fans? Not sure how they work exactly, but it was a question for which I did not have an answer….
Thanks!

18. Rachel Schaus says:

Matt here I live in Ankara Turkey and I made this flying contraption. I flew aroud the house a couple of times but soon got bored of flying it off the staircase so I went to the top of our 10 story apartment building (100 ft.) and let fly it was fun to see it swoop and glide down to our bache.Then I went and got it. So my advise is try to fly it as high as you can get.

19. LJ J says:

Kids and I had fun making the hovercraft, it’s our third experiment, but the first on your site. They had a ball. My son loved watching the video, I liked the supply list and the teaching support, and my daughter was so eager to record it, that she grabbed pencil and paper and drew the experiment, laying it out as you suggested in a scientific journal. Thanks for a super experience!

20. Donna Short says:

Wow! This was our first experiment to do. I finally made the time to get on your website. My kids, 10 yrs, 9 yrs and 7 yrs. thought this experiment was great!!! Lots of fun!!! Thank you !

21. Welcome to our science family!

This is one of the very few experiments that doesn’t have a detailed explanation with it (it’s more of a quick-start activity), however you’ll find more detailed explanations in the comments below this one. After reading those over, let me know if you have specific questions I can answer for you! Also – since it’s summer, please do look at the “Flight Lab” in the summer e-Camp section, which has much more detail about how and why things fly.

22. Amy Bridges says:

Hi There! This my our first time on the site. Sarah chose Flying Contraptions on the Getting Started menu. She’s ready to do the experiment…but how do I find the teaching content that explains why the contraption flys?

it was cool! especially when you drop it from the top of the staircase!

24. After watching the video carefully and making the flying machine, you’ll want to throw it HARD. Try asking a grown up to help toss it around. If you send me a picture of your experiment, I might be able to make a suggestion. 🙂

25. Michelle Anthony says:

Hi! I tried this experiment and it did not work. How do you make it fly? Do you have any tips?

26. Anonymous says:

hi aurora my experiment worked! this was my first experiment. it was fun! from Sophie. I’m 8.

27. I meant to say that it LOOKS like it shouldn’t fly… because where are the wings? 🙂

Why did you say that the Hoopster will not fly when it really flies?

29. You’ll find a further explanation in the comments before this one… 🙂

30. Jennifer Merrill says:

WHAT makes it mathematically incorrect Aurora?

-Andy(Jen’s son)

31. thomas gaitens says:

my 6, 8 and 11 year old…had more fun in 15 mins with this than all day

32. Pamela Church says:

flies great! spins a bunch too.

33. Jessica Dilbeck says:

Both my boys (9 & 11) love this experiment. They made several-added lots of rings and measured how far each one would go. Very easy but very educational. Thanks so much.

34. Sherry Phelps says:

Heather loved it. She and her sister, Taylor will be working on many variations. They are testing against various flat wing paper airplane designs.

35. I am sorry you had trouble! Sometimes you have to throw these HARD, depending on how you made them. The biggest problems I’ve seem with this project are if you used paper instead of an index card (the hoops are too flimsy) or the loops are not lined up with each other. Science is like this sometimes, so it’s a great opportunity to teach your kids observation skills.

2. Why do you think that happened?
3. What’s one thing you can change to affect it?

Keep trying! I know you’ll get it, and I’m here to help. If you’re frustrated, try a different experiment and see how it goes… then come back to this one. Even scientists need a breather now and then.

36. mjfranklin says:

None of my 4 boys could get this to work, and neither could I. 🙁 We followed the directions. They just went forwards a very small distance, a foot maybe, then fell to the ground. We made 5 of them but none of them did anything interesting at all. A little disappointed so far.

37. Liam Fishman says:

I think this experiment is cool!

38. I do a whole lab on this during my summer e-Camp… in the meantime, you can find it in two places:

Does that help?

Aurora

39. Isabelle Hidaka says:

Hi Aurora,

We had a fun time trying this out.My son (8) added more rings and we both had our own flying through the appartement.This afternoon will go outside for some kite flying and our two new additions to experiment how those little guys do with strong wind!:)
Also,I wanted to know where I can find something on kite to explain flying,drag,air pressure etc…to a 3rd grader!
I poked around but wasn’t successful!:}

Thanks for all you do,
Isabelle

40. Elaine Thigpen says:

Both of my kids (8 yr and 14 yr olds) are enjoying this. They going further in this experiment trying more loops, adding straws to make it longer to see which one will go the furthest. This definitely better than paper airplanes. Thank you, Aurora.

41. Jeanette Chamberlain says:

The kids were like, what are we making? I didn’t let them see the video at first. After they made them, they loved doing this. Thank you for making this fun for them and it was fun for me as well.

42. nazia atique says:

My 8-yearold said, “It was cool!”

it was cool!!!

45. Michelle Hughes says:

This was fun! My kids were so thrilled that it worked, even though I had a hard time explaining the “why”, but now they are experimenting with combined ones, different lengths, etc. Thank you!!

46. Suna Price says:

Wow! I can’t believe this goofy contraption really worked! It flew across our room really far! (Tyler- age7)

47. Which part did you have trouble with?

48. denisoncrew says:

I could not get it to work…. 🙁

49. Yes, it could be!

50. Lydia Fancher says:

try it with the small part in front, it will have a better chance of flying far!

51. Lydia Fancher says:

THIS COULD BE THE NEXT TYPE OF PLANE!!!!!!

52. Yes, all the experiments are performed on the videos. And yes, the flight lab is being worked on now for release this summer.

53. Ann Frazier says:

I have a suggestion for anyone who is having trouble with the glider falling apart when it lands. I found that masking tape worked better for me than regular tape in keeping the circles on the straw. This was a very fun experiment!:) -Madeline (Ann’s daughter)

54. Cheryl McDonald says:

We just joined up and I can’t wait to try this with the kids! Time for a trip to the \$ store for straws. 🙂 Two questions:

Do you ever perform the experiments on the videos?

I clicked on the link you have for this experiment and received an error message that the file no longer exists. Is it being updated or is this an old link?

Officially, it’s located here in the Flight Lab:
https://www.sciencelearningspace2.com/summer-camp/flight-lab-experiments/

55. Iris Ensley says:

My 7 year old daughter was excited when she saw her
plane fly…and I was too!

56. Mia Curlin says:

interesting! they dont have these in paper airplane books

57. This is one of small handful of quick-start experiments we have under the ‘Getting Started’ menu that uses everyday stuff from around the house.

Officially, it’s located here in the Flight Lab:
https://www.sciencelearningspace2.com/summer-camp/flight-lab-experiments/

The video streaming will depend on your internet connection. Here’s something you can do if it’s slow: click PLAY, then click PAUSE and wait for it to load completely, then hit PLAY again. We’re currently working on getting all the videos to stream smoothly, but it takes awhile to update 700+ videos! Let me know how it goes so I can help.

58. Sue Ishak says:

Am I missing something? Can’t find materials list for this experiment, video starts mid-way and is choppy (all other videos on this site play fine). I can figure out what to do from the partial video here, but we’re new to e-science and I prefer my kids to view the whole experiment from prep to finish. Sadly, we’ll have to skip this one until we’re able to view it all 🙁
Also, what unit of study does this experiment go with? Where can I find similar activities, further explanations? Thanks

59. Yes, give it a GOOD hard throw… and see how it works!

60. billy coleman says:

Do you just throw it?

61. billy coleman says:

How does the Flying Contraption Work????

62. Did you find it in the previous comments?

63. Joanne Trewick says:

Where do we click on to read the explanation of why this plane can fly when it shouldn’t be able to?

64. Abby Edmunds says:

Hey! This is a pretty cool looking paper plane! Now I can show it off to my friends and watch their mouths drop open in awe! Yay for science!

65. The four forces are lift, weight, thrust, and drag. All airplanes and flying objects have these four forces acting on it. Lift generated by the wings counteracts weight, thrust from the engines (or from a good throw from your wrist) counteracts drag (the friction from the air).

66. Helen Morton says:

Aurora – What are the four forces that you are referring to in your explaination as to why these flying contraptions should not be able to fly mathmatically?

67. Athena H says:

Another great flying contraption. We have a collection now. Thanks!

68. Rajkumar Chakraborty says:

This one is a wired one but still good.

69. Karen Yanes says:

This is our very 1st experiment and it works so well! Very excited about this program. Thank you!

70. Katherine Kryger says:

We didn’t have straws so the kids decided to use bamboo skewers! (the pointy end was covered by a loop anyway)
They are experimenting with various loops, widths, etc. and are having fun! 🙂 Thanks for the fun science adventure!

71. Rachel Hearn says:

i gust dont get it!!!!!!!!!!!!!!! hymmmmm,……. lol!!!!!!! now i get it!!!!!!!!!!!!

72. Did you see the hints in the other comments? Tell me what YOU think! 🙂

73. Melissa Beck says:

Very fun experiment, but we are looking for the “why?” …..”Why isn’t it supposed to fly (mathematically speaking)?”
“Why DOES it fly?”

74. Jinky Kieft says:

My son (6) made 3 of these already on his own. He loves it!

75. You’ll find direct links to online suppliers (like Radio Shack) on the main shopping lists for the items. Look above in the main bar that says “Shop List” and click on the unit you are working on. If there are items not easily found at the grocery store, then they will have an appropriate link. If you have trouble finding an item, please let me know so I can direct you.

76. Shieron Phillips says:

My daughter was able to get the first project done and loved it. I am glad that she can do this with you.

We would like to find out where or order form is for some of the things from Radio Shack. We need to order some of the main components. Thanks

77. Carrie Lorfano says:

Thank you! This will be our first official experiment on your site. I just previewed the video, but I’m going to allow my oldest to take the reins for the actual assembly.

78. You can vary and change the flying contraction by: placing a paperclip at the bottom of the small hoop, building a really loooong one with multiple straws, make a double or triple (or more) by placing the small hoops side-by-side and the large hoops side-by-side and taping them together (you can also create a pyramid stack of these – I will post a photo soon.

Read over the previous comments for ideas on how we think they fly… I’ll post more with the photo.

79. Kelli Simonds says:

My kids were able to make this all by themselves with me just supervising (They are 7 & 8 years) so they were really impressed that they were able to fly and and figure it out themselves. We only had “bendy” straws so I assumed it wouldn’t work, but it did!

80. Carol Comanse says:

very cool

81. Sherrie Swerbensky says:

Would you explain how to attach more than one? I tried a few different ways and it wouldn’t fly. Is there also a description on why/how they fly? My children are trying many variations trying to figure it out.
Thanks!

82. Kristy Holhos-Vaida says:

We were out of straws but we had CHOP STICKS and it worked! Ha – great fun – Thanks Aurora! – Mom
I REALLY, REALLY, REALLY LIKED IT! – Hannah age 11

83. Try it! 🙂 And then let me know about it…

84. Danielle Elizalde says:

Hey this looks awesome! Can it work with a wood securer instead of a straw?

85. Kristine Besic says:

socool

86. Ekaterina Belousova says:

This is AMAZING! I’ll be trying this as soon as I have the chance!

87. Linda Usita says:

I can’t believe this!! My mom had alot of fun doing this and so did i. – Tara [ daughter of Linda]

88. April Poley says:

Great experiment. We experimented with the different ways to throw it. My daughter, who is more into art than she is science, is having fun decorating her card pieces with drawings and my son has moved onto experimenting with changing the sizes of the hoops and the length of the straw. He is also going to attach several together to see how they fly.

89. Molly Marlow says:

so cool trying it now

90. Holly Loussaert says:

This Is Cody. We made a flying contraption. We used three pieces of cut paper, then we used a straw, and two pieces of tape. When I threw my contraption, It spins in the air. whoo!

91. Anonymous says:

We redid the experiment with a super size drink straw and it FLEW! our index card (4 x 6) was too heavy for a normal straw. That was why it didn’t fly the first time. What a great experiment! Rebekah say’s that she can’t believe she actually made an airplane that flies.

92. Anonymous says:

OMGoodness what an awesome first experiment! We had the best time doing it together and then trying to fly it together too! What an afternoon.

93. María Zamparelli says:

Fantastic!! Aurora. My son is working on several paper airplaines to see if it makes a diference to use a shorter straw or a thinner paper ring. Great project. Thank you, María Z

94. Sara Walker says:

IT WORKS! My boys doubted you! Not anymore…thanks for making science super fun!

95. You’re right – it’s a bit complicated to explain outside a graduate level aerodynamics class, but here goes: there are FOUR forces at work with your flying machine. Gravity is always pulling it down, but air keeps it up (lift). The way airplane wings generate lift is by having a curved surface on the top which decreases the sir pressure, and since higher pressure pushes, the wing generates lift by moving through the air. But what about a flat wing?

If you drop a regular sheet of paper, it flutters to the ground. If you wad it up first, you’ll find it falls much faster. The air under the falling paper needs to get out of the way as gravity pulls the paper, which is a lot easier when the paper is wadded into a ball. For a flat wing (like on a paper airplane) to glide through the air, it needs to be balanced between gravity and the air resistance holding it up. In order for a glider to fly, the center of pressure needs to be behind the center of gravity. By adding paper clips to your paper airplane, you move the center of gravity and center of pressure around to find the perfect balance.

When we use math to add up the forces (the pull of gravity would be the weight, for example), it works out that there isn’t enough lift generated by thrust to overcome the weight and drag. When I say, “mathematically speaking…” I mean that the numbers don’t work out quite right. When this happens in science for real scientists, it usually means that they don’t fully understand something yet. There are a number of ‘unsolved’ mysteries still in science.. maybe you’ll be able to help us figure them out?

96. Mere Hata says:

Hi Aurora
Can you please tell me why it is mathematically impossible to fly, bearing in mind that I am not mathematically or scientifically minded.

Thanks

97. Teresa Knorr says:

we just did this and we were wondering why this would work even though it Mathematically shouldn’t?

98. Deanna Betts says:

We didn’t think this one would work– I was really surprised- looking forward to putting two together tomorrow. Thanks for a great first day of camp.

99. Stacie Carlson says:

We had a super day with all the wonderful science experiments! Thank you so much!