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JPL Annual Invention Challenge - 2001 Results Gallery |
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Welcome to the 2001 JPL Annual Invention Challenge's Invention Gallery.
Clicking on the titles will provide notes from each contestant about
what they invented, how they made it, and lessons learned from their
invention. The title for this year's contest is the Water Balloon
Launch Contest. The objective for this year’s
contest was to create a device that launches an official water balloon
in a vertical direction. The contest winner will be the person whose
device launches an official water balloon the highest above the
ground and has the balloon contact the ground intact within a specified
circular target.
For the rules please Click Here! Questions
related to this contest should be directed to: Paul MacNeal at:
work phone (818)354-7824, FAX (818)393-4950,
MS 301-451, located in Building 301-460B,
or e-mail to paul.d.macneal@jpl.nasa.gov.
If
you would like to borrow a copy of the 40 minute video of this
year's Invention Challenge event, please phone Paul MacNeal at
(818)354-7824 or e-mail a request to paul.d.macneal@jpl.nasa.gov.
Videotapes of the 1998, 1999 and 2000 Invention challenges are
also available.
As organizer of this year's event, I would
like to personally thank all of the volunteers who helped to make
the event such a wonderful experience. I estimated the turnout
to be around 350 strong under beautiful weather conditions. A
special thanks goes out to Randii Wessen for donning a rain slicker
and entertaining the crowd for nearly 2 hours. Special thanks
also go to Ken Berry and James Rose for preparing this web page.
Plans for next year's event are already underway. The rules for
the 2002 contest will be available at the end of August 2002.
2001 Invention Challenge "Water Balloon Launch Contest" Participants
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| Winners Etc. |
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| Bowserbowl Ballistic Balloon Booster (2nd Place - JPL) |
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| The Greater Rotator |
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| Magnetic Accelerator |
The idea - what stimulated your idea, which ideas did you toss out?
Those of you that attended the event know that the true source of power for my invention came from a "special" magnetic circuit that accelerated the aluminum carriage holding the balloon to a high velocity. This information is "Top Secret" and is so complex that it is not easily explained to the general public. However, surgical tubing provided the initial acceleration, before the "special" magnetic circuit took over.
I thought of a catapult, an air powered system, or something using centrifugal force.
At the time, I thought surgical tubing would be an easy method of propulsion.
Building the invention - general list of materials, challenges, changes as you went through.
I wanted a device that adhered strictly to the rules, of 1) one operation to initiate the launch sequence (I read this in the strictest sense to mean one operation for the launch sequence after the balloon was placed in the device, 2) the device was to be no higher than 2 meters before, during and after the launch sequence, 3) the balloon must place the initial trajectory within 3cm of the target centerline 2 meters above the ground and 4) I wanted a device that could do two launches within the five minute time period. These criteria greatly affected the design of the device.
First, I did not want to place the balloon in the device with the surgical tubing fully stretched and then cut a string or throw a switch. I didn't want to be anywhere near the device with the tubing stretched as I considered it somewhat dangerous if something were to break. I therefore opted to utilize an electric motor to stretch the tubing, this complicated the design, as I had to design an electrical circuit to start and stop the motor and a mechanical system to stretch the tubing and release the balloon after the tubing was fully stretched.
The second consideration was that the device was to never be more than two meters high before, during or after the launch sequence. This required placing a positive stop at the end of the travel. With a simple slingshot device and a pouch, there would have been nothing stopping the pouch and the tubing from extending out the top of the device above the two-meter mark. Again this complicated the design because I now had to stop the carriage that held the balloon without breaking the balloon.
Thirdly, I wanted to consistently be able to place the trajectory of the balloon within 3cm of the trajectory centerline. To accomplish this I used three lengths of music wire to guide an aluminum carriage that held the balloon. This required stretching the music wire very tightly, I therefore opted to build a metal frame to hold the wire stretched.
Lastly, because of the above design considerations, two launches in five minutes presented no problem. Once the device was leveled, the launches were consistent and the second launch required very little set-up time.
Testing - what you learned, how you modified the design, how you tested.
The major modification I made during testing was the design of the aluminum carriage. The initial design was made from sheet aluminum and welded together. I used a stock nylon bushing purchased at Home Depot as guides on the music wire. Because of the force of the impact against the fixed stop, this design failed after two or three launches. I then went to a solid aluminum carriage. When I went to the solid aluminum carriage, I also added Teflon bushings sized to the music wire.
Originally I used 1/32 aircraft cable for the mechanical systems that stretched the surgical tubing and released the carriage. This would consistently break next to the ferrules. I went to 1/8 cable for the connection from the motor to the release mechanism, 1/16 cable from the release mechanism to the carriage and ended up with 80# fishing line from the release mechanism to the surgical tubing. I also placed a plastic insert to hold the balloon in the carriage as the force of the acceleration widened the balloon more than I expected.
Competition Day - feelings about the competition, struggles you overcame, comments about the organization of the event, comments about other entries.
I was very relaxed on competition day. When I first decided to enter the contest, my wife asked me if I realized where I worked. She pointed out to me that there are real "rocket scientists" working there and that I am an accountant. I said it would be fun and that I did not expect to win, although it would be humiliating to be beaten by an elementary school entry.
I had two sets of surgical tubing with varying strengths. My plan was to do the initial launch with the weaker set just to get on the board and if necessary adjust the leveling mechanism to bring the landing closer to center target. I would then use the stronger set of tubing to try for a higher altitude. As it turns out, the first balloon seemed a little larger than the ones I practiced with, did not fit into the carriage well and broke on the launch. Because of this I didn't replace the surgical tubing with the stronger set. I took more care with the second balloon and had a successful launch capturing third place.
I think in the future, if there is a time limit to the event, it would add to the excitement if there is a visible timing clock with a bell or whistle sounded when the time is up. This would keep things moving and be fair to everyone.
Hindsight - how you would have done things differently.
I would change the design of the carriage. I would still use aluminum, but I would make it deeper and wider to better hold and cushion the balloon. I tried to work with tolerances between the balloon, the carriage and the frame of the device that were unnecessarily close.
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| Flying Nimbus |
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| Old Faithful |
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Old Faithful was made of 2 by 2's, resembling somewhat a phone
booth, and just under 2 meters tall, as restricted by the rules. The
taller, the more gentle would be the force.
Motive power was a pair of garage door springs, providing the most
(legal) energy I could think of. Since the springs could only be
extended 18 inches, I used a set of pulley blocks to increase the travel
by a factor of three, using up most of the 2 meter space.
The balloon cradle was a spun metal mixing bowl (.75 qt.), which
turned out to be too big - all of the test balloons burst on launch. A
cottage cheese container, epoxied to the mixing bowl, lowered the launch
stress and saved the balloons.
The wind up mechanism was a foot treadle hooked up to a pair of
ratchet pulleys. Launch was accomplished by cutting a rope link. It was
disconcerting how easily the knife released all of that energy.
Garage door springs were a big mistake; surgical tubing would have
been a better choice. The springs are quite heavy, which lowered the
efficiency of Old Faithful to about 20%. Furthermore, after each launch
they bashed the structure and ropes out of alignment, making calibration
difficult.
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| The Ozzy Tesser Action |
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| Ballooon Blaster |
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The idea of using compressed air in a plenum to propel the balloon
up a vertical barrel was motivated by the desire to make the device
as simple as possible. A quick calculation indicated that even a
modest pressure of 10 psi, acting over the surface area:
3.14*((3in)^2)/4=7in^2 of a balloon, which weighs 300gm=0.67lb, up
6 feet of barrel would yield more than enough height:
H=10psi*(7in^2)*6ft/0.67lb= 627ft. When my first attempt with a
prototype device yielded less than one-tenth of this, I realized
that I had neglected to take into account the friction between the
balloon, which is compressed by the 70 lb force and resulting
acceleration, and the wall of the barrel. If the friction
coefficient is 0.2 the friction force is 0.2* 3.14* 3in*2in*10psi=
38 lbs, and it can be considerably higher. Therefore a rigid casing
(sabot) was required to hold the balloon so that it wouldn't expand
into the wall of the barrel. I used the bottom half of a plastic
bottle, tied with a string so that it wouldn't exit the barrel. The
barrel was lubricated with dry lubricant, as I quickly learned that
WD-40 and other hydrocarbon lubricants break balloons! Originally,
I purchased a valve to release the compressed air in the plenum,
but some experimentation showed that I couldn't open it quickly
enough, so I went to a burst diaphragm made from of a bicycle inner
tube stretched across a flange between the plenum and the barrel.
This burst diaphragm consistently ruptured at a pressure of 13 psi
and was much simpler, safer, and quicker than a valve. One of my
intermediate designs had a curved barrel (with a 4 ft horizontal
section, a 3 ft radius bend, and a 3 ft vertical section) to
increase the distance over which to accelerate the balloon.
Thankfully, the night before I assembled the curved design, I
calculated the centrifugal force as the balloon went around the
bend, and learned that the barrel would not hold together, so I
abandoned this idea in favor of a straight vertical barrel, with
the balloon sitting at the bottom. I tested the final devise
extensively over Thanksgiving. (One proof test used a double
diaphragm, which resulted in a burst pressure of more than twice
the 13 psi value used in the contest.) I found that even a slight
wind would blow the balloon twenty to fifty feet off course.
Therefore, I was extremely concerned about the safety of the
spectators, and was very happy to pack it in after my first shot in
the contest missed some small children, and the target, by about
two meters.
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| Ballooonatic |
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Balloonatic
Balloonatic, our first entry, is a highly complex, and some would say elegant, pneumatic launching platform. It has an 18-gallon accumulator storing compressed air which is released when a 3" ball valve opens to propel the water balloon into orbit. The ball valve is fully opened almost instantaneously by two pneumatic cylinders when a solenoid valve is energized. The water balloon travels through the 6" barrel that is cradled by a carrier to maintain its shape during the high acceleration. Once the carrier hits a dampened stop at the top of the barrel, the balloon maintains its velocity and hurtles skyward. A rising vortex of air generated by an air moving system just prior to launch eases the balloon's entry into the atmosphere. The balloon trajectory can be finely tuned by adjusting 3 legs equipped with casters that enable Balloonatic to be mobile. The entire launch sequence is controlled using a specially programmed computer.
We spent three weekends and some late weeknights constructing Balloonatic, with much support from understanding, then slightly irritated, and finally, "sign this document" wives.
Balloonatic - Design and Manufacturing
Dawn, 1 week to go. Fog drapes a secret facility located close to LAX from which emanates the frantic sound of hammering, filing and drilling, interspersed with the occasional curse.
Four men and a dog work; and the Balloonatic takes shape, drawn from highly specialized OTS (off the shelf) parts fiendishly modified by skilled engineers: tanks, tubes and turnbuckles.
The First Test
Tension fills the air as the electronics support team, Said and John, program and wire the computer controller. The barrel is loaded with a balloon and the Main Accumulator Tank is charged up to 60 PSI. For some curious reason unknown to us, Cody (the dog) skulks away to find refuge behind a concrete wall.
5-4-3-2-1..all heck breaks loose, a maelstrom of air, water and vaporized balloon skin surges into the heavens, followed by a 15 pound chunk of aluminum - formerly known as the air mover. All of this takes place in a space of time shorter than the written explanation, and yet it appeared to happen in slow motion (a common occurrence in events which preclude bodily injury or worse.).
Analysis
Like all scientifically minded individuals we had taken the precaution of video-taping the first test. The tape did not reveal much about what went wrong because that was obvious: too much pressure, but it was an interesting study in human nature: 6 complete idiots standing next to a highly dangerous piece of equipment
on the brink of exploding, oblivious to the danger, followed by one individual (who shall remain nameless), long after the event has occurred, turning and running while mouthing words which looked suspiciously like "Mommy". Should have listened to the dog.
Pressure was backed off to 10 PSI and a new highly specialized balloon carrier was designed using solid modeling software. (We coincidentally found something exactly like it at Home Depot for 69 cents.)
Further tests with incrementally increased air pressure proved to be extremely successful. This led us to an overcast evening before the competition, casually launching one balloon after another skywards to heights which would involuntarily tear screams from our mouths.
Competition Day
The day dawns warm and breezy, not ideal conditions for a launch, the team shuttles over to the Jet Propulsion Lab. A crowd starts to gather as other contestants arrive with oddly shaped and mysterious machines, lots of wood and surgical tubing.
At the weigh-in, the Balloonatic compressors will not fit on the scales, guaranteeing us a prize as the heaviest entry.
As nerves steadily rise, we confidently volunteer to go first into the arena: a 7 meter diameter circle into which the balloon must splash down. Preparations are made as the announcer badgers us with questions, soon we're ready to hit the red button...
5-4-3-2-1....hiss - kachunk - thwang! A large piece of rubber (the carrier damper), hurtles skywards in a plume of water much to our humiliation and the entertainment of the audience. Meanwhile, we stand there stunned. What went wrong? No time to think.remove the barrel and fit a new carrier (yes, we had brought a spare) only to be confronted by a broken screw. We push the whole contraption out of the circle in defeat and bewilderment.
What Went Wrong?
The evening before the test we had launched multiple times eventually destroying the carrier. This gave us an idea of the maximum force (and hence, air pressure) "a carrier" could sustain. We then placed a new carrier in the barrel - but we failed to perform just one test launch with the new carrier, and so we entered the competition with an untested machine! As far as why the first shot failed, we'll never know for sure.
The Return of the Balloonatic
No chance to win, but definitely a chance to prove the might of our machine. Once again we stand in the arena. Once again we prime the beast. Once again we press the red button.
5-4-3-2-1.deafening silence. Something has gone amiss with the computer controller sequence; the ball valve did not open. A wiring check does not reveal anything obvious, perhaps it was the heat, or our cotton mouths (user error), 2 more attempts with the same result. In the great tradition of all downtrodden and lambasted engineers, a fighting spirit arises.plug the sucker into the wall.
5-4-3-2-1.whoosh! A balloon takes flight, arrow straight into the Southern California blue. At its apogee, the balloon is suspended, on the brink of its descent, silhouetted against the waning Moon.
A Victory of Sorts
The Balloonatic won the prize as "The Heaviest" and also managed to get the second best height (and that with a partially discharged accumulator!) What could have been.
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| String Theory |
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| Cloudbuster (Unofficial Highest & Most Artistic ) |
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| Ballooon to the Moon |
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"Odyssey of the Mind" is an after school activity that encourages creativity
and problem solving. The students, working in groups, have to solve various challenges, some of which include constructing devices. At the end of the year, they have the opportunity to enter an organized
competition. Here is a link to the Odyssey of the Mind (OM) website in case you want to know more: http://www.odysseyofthemind.com.
I had two daughters participating this year so I suggested that the students build a balloon launcher for the JPL design contest as a form of practice for their OM program.
The students were VERY receptive to this idea. For several weeks, I would go to their Thursday afternoon meetings and work with the group to come up with an approach. Part of the OM philosophy is that
the students must do all the work and the ideas must be their own. With this project, we bent the rules just a little (some parents helped with the actual construction, but even so, most of the actual
construction was done by the kids, including some first graders).
These children are very imaginative. They came up with at least thirty possible names for their project. Then they invented a voting scheme to select the final name, "Balloon to the Moon." One of the local
newspapers liked it so much they used it as the title of their article describing the JPL contest. The kids came up with almost as many ideas for propelling balloons, some of which were a little impractical.
With some guidance, they settled on using stretched rubber. It turns out that Sports Chalet has a water balloon launcher, so they chose to use this COTS technology at the heart of their design. This still
left plenty of challenges for them in how to support the ends, and how to release the stored energy.
On the day before the final event, every student successfully launched a water-filled balloon. On contest day, we discovered that the competition balloons were filled with more water than the balloons they
had used in practice. These larger balloons broke on launch, which was a huge disappointment for the group. In retrospect, for the second launch attempt, we could easily have reduced the amount of stretch
of the rubber by using a longer loop of string at the bottom and this would probably have yielded a successful launch. Hindsight is always 20/20. I still don't know exactly how the students got the wrong
amount of water in their practice balloons.
The kids learned a lot and had a great time. I enjoyed it too.
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| SHADY |
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Our idea was scribbled on a napkin in our garage, Shady was going to be
an awesome firing machine. Our idea was loosley formed, and was basically
using a garage door spring and then pulleys to pull a small basket inside our
ABS tube, and then release the baloon at the top.
We used two inch square tubing for our base, welded in the form of a
triangle. A six foot ABS pipe was also used, four inch diameter for the shaft
that would house the balloon basket. Pulling would be done via a thin,
1/4inch steel wire.We made the contraption as we went along, modifying it and
seeing what worked and what didn't. The trickiest thing was making a release
mechanism that was easy to use. A winch pulled the basket down from the top
of the pipe, and stopped at the bottom. We had a hook attached to the winch
in order to pull the basket down, and then pulled the hook out of the way
with another cable attached to the side of the hook. It took a lot of sanding
to make it work right.
While at the contest, I was surprised by the number of spectators around
the event, and it was cool seeing the kids from elementary school
participate. I was also surprised at the complexity of some designs. A very
fun event, and I learned that on average, the simplest balloon launchers
worked the best.
Looking back, I think the only thing I would change would be to make our
spring stronger, and the cable a larger diameter. It was scary cranking the
cable. Luckily, everything worked out, and we made our launches in the circle
both times within five minutes. An awesome event, our team looks forward to
it next year!
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| WHOOPS |
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The building of WHOOPS.
Clearly a sling shot seemed to have the best flinging power. By storing the
energy in a circular motion the energy could be increased slowly to the bursting
strength of the balloon, thus obtaining the maximizing velocity. At first I thought
of a counter balanced weight that would at the last minute shift to the center of the
transferring all it's momentum the balloon just before launch. This would also
balance the empty device. This idea was quickly scrapped do to complexity. Major
problems were bending of the main radial arm causing the release mechanism to contact
the support backing. Also release mechanism was fabricated only minutes before
the contest. Clearly the 12 volt Honda blower motor didn't provide the adequate
tork. Perhaps a 10 HP or 20 HP electric motor would have done the trick. I only spent
two weekends working on this project and it showed. All I can say is Whoops!
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| The Loophole (Longest Time Aloft & Most Unusual) |
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Our second entry, The Loophole, is appropriately titled because it is designed around a small loophole in the rules. The rules state that the highest balloon that hits the target wins and height wil
l be calculated based on time aloft. So one of our twisted engineers (Dave) came up with the idea to hover the balloon. We brought a few air moving devices into our lab in order to find out if we co
uld actually hover a water balloon. The best device turned out to be a leaf blower, but it only hovered it about a half of an inch. not adequate enough. The design evolved into the use of three iden
tical leaf blowers funneled together into a standard 3 to 1 ABS fitting.
The Loophole - Design and Manufacturing
After finding the flaw in the competition rules, evil genius Dave came up with the idea of simply floating a balloon for 5 minutes, thereby guaranteeing victory. Assembly was achieved using 3 leaf b
lowers, miscellaneous ABS adapters and duct tape.
Testing and Analysis
Ironically, the tests did not seem to go well, as instability resulting from air moving over the imperfect shape of the balloon caused oscillations which would topple the balloon groundwards. But Da
ve decided that as long as the JPL balloon has a consistent shape, that there was ample power available, and that the wind was light, all would be well.
Competition Day
The day dawns warm and breezy, not ideal conditions for a launch, the team shuttles over to the Jet Propulsion Lab. A crowd starts to gather as other contestants arrive with oddly shaped and mysteri
ous machines, lots of wood and surgical tubing.
The Loophole Redemption
Dave waits patiently in line with The Loophole as we beg the judges for another try with Balloonatic and they consent. Soon, it's Dave's turn. With Said and John, he prepares the machine and so come
s the big revelation: the rules say maximum time aloft and not maximum altitude! A gleam of recognition, nay respect, shines in the collective eye of the audience (accompanied by a groan or two). Da
ve wipes his brow as he places the balloon in the barrel of The Loophole.
5-4-3-2-1.the balloon shudders then hovers at about 3 inches.laughs of ridicule, but no, the computer controller kicks in the other 2 blowers and the balloon positively levitates above the trip sens
ors (used to trigger the time of flight). Thunderous applause ensues. Dave throws his arms into the air in victory. The impossible has been achieved - a water filled balloon dancing on a column of a
ir - we must win!
"Okay, you've made your point, turn it off", and Dave wheels The Loophole away.
The Return of the Balloonatic
No chance to win, but definitely a chance to prove the might of our machine. Once again we stand in the arena. Once again we prime the beast. Once again we press the red button.
5-4-3-2-1.deafening silence. Something has gone amiss with the computer controller sequence; the ball valve did not open. A wiring check does not reveal anything obvious, perhaps it was the heat, or
our cotton mouths (user error), 2 more attempts with the same result. In the great tradition of all downtrodden and lambasted engineers, a fighting spirit arises.plug the sucker into the wall..
5-4-3-2-1.whoosh! A balloon takes flight, arrow straight into the Southern California blue. At its apogee, the balloon is suspended, on the brink of its descent, silhouetted against the waning Moon.
A Victory of Sorts
The Loophole won the prize of "Most Unusual" much to Dave's irritation, as he believes (as do we all) that The Loophole was the outright winner with 90 seconds hang time. The next longest and the cr
owned winner was 5.75 seconds - but rules are rules and the Ref can't be wrong.right?
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