MythBusters Episode 32: Jet Pack
Air Date: June 9, 2005
A Jet pack can be built from plans purchased off the internet and limited funds.
busted
The jetpack produced by the Mythbusters was not powerful enough to even lift itself off the ground, and they had to cheat by going beyond their assigned budget, in order to create it. The sum of its parts cost too much to allow the average person to build it on a budget and the plans did not have enough details to give builders a clear example of what to build.
"Pyramid power" can be harnessed for a variety of purposes around the home.
busted
The build team constructed a series of pyramid frames using the precise measurements and dimensions required to "harness" pyramid power. Four tests were performed: keeping razor blades sharp, preventing food from spoiling (one test for milk, another for an apple), and preventing the decay of a flower. The apple test at first seemed to be working, however it was later discovered that a contaminated saw blade (used to halve the apple) may have given one half a higher microbial load than the other. A repeated test using sterile equipment yielded approximately the same decay rate for each half. Strangely, a similar test with ‘cube power’ showed the fruit rotting at a faster rate than the other two tests.
This myth caused Adam to comment, "No more ‘oogie-boogie’ myths, please." (The MythBusters don’t normally deal with paranormal myths.)
Newer: Episode 33: Killer Brace Position
Older: Episode 31: Breaking Glass
On the Jetpack episode you use lawn blowers not jets on your back or something like that…like the jetpacks in movies.
June 23, 2007 at 6:03 PMI am not sure whether all the power of the engine was actually getting to the propellors. I think that much of the power was being absorbed by the belt which is use to transfer power from the engine to the propellors. It would have been better to place two smaller, streamlined shaped engine directly beneath the propellors to ensure minimum wastage.
August 5, 2007 at 10:16 AMThe duct fans built did not produce but half the lift expected. Did they think to change the pully sizes on the engine or ducts to increase the speed of the duct fans? If there was power to spare from the engine I would think they should have made the fans sping faster. i.e. more lift.
August 24, 2007 at 4:21 PMIf you dont wast your time with plans fans and ducts you can build a jet pack from model airplane jet engines, but four engines at 6,000 a pop put a dent in anyones budget.I have played with the idea. and would be glad to give you my insight.
August 24, 2007 at 9:38 PMPersonally i think it can work, but if they treated it like a small helicopter, as one person said with lift probs, and i think with the implementation of a jet turbine, of reasonable size to provide enough power to turn the blades and for the exhaust to provide additional thrust it may work. or even for the exhaust to run into something like a car turbocharger which will in turn provide more air for the turbine equalling more power to the blades. thats my two cents.
January 16, 2008 at 2:50 PMtheproblem with the jet pack experiment was they tested the rig in an enclosed space.
this let the air circulate instead of disperse so you eventually get a motor boat in a drainign toilet effect. the boat makes headway against the swirling water but appears to be standing still.
even hoverjets like the harrier were first tested over special runways with screens and vents below the jet blast so the air wouldn’t simply recirculate.= through the engines but would actually be pushed away from the plane through the underground vents so the plane could lift off.
they should take the jetpack outside and put it on top of a hanging crane thern try it so all the air blast goes downward and has little chance of recirculating around and back into the ducted propellor intake.
even heliciopters must guard against creating the situation of recirculating airflow. with them it is called settleing into flow when they come down so fast they settle into their own prop wash and the helicopter is simply recirculating a donuts of air in the vicinity of the helicopter blade disc instead of displacing air. the helicopter loses lift and crashed.
January 31, 2008 at 7:35 PMthis was the cause of the first Osprey marine vehicle crashes.
i saw the james bond episode super cool
April 22, 2008 at 8:13 PMthe jet pack one was boring.
May 8, 2008 at 1:12 PMI think your plans for the ‘jetpack’ were flawed from the start, the gear ratio’s were the wrong way round, you had the small cog on the engine shaft and the large cogs on the fans, this effectively reduced the fan rpm to at least half that of the engine!, now if you had had 1:1 ration (same size cogs for engine and fans) then you would have doubled what you had on the show (thrust that is), also if you had reversed the cogs, large on the engine and small on the fans, you would probably have quadroupled the rpm available!! so would you give it another go, seems a shame to waste such a good bit of engineering!!!!
August 23, 2008 at 10:26 AMWhat if you use actual jet engines, or ionization rockets. All you need to have to make an ionization rocket is a television, a cylinder, and two plates which i don’t know what they are made out of.Take the electron gun from inside the television and put it inside the cylinder.At the other end of the cylinder put the two plates there about one and a half inches apart from each other. Drill a whole quite big at the end of the cylinder where the two plates are but don’t drill into the plates them selves. Cut the end of the cylinder. On the side of the cylinder with fan in the whole to suck air into the cylinder. What should happen is the when the electrons combine with the air molecules the get ionized and when they get between the two plates the go zooooooooming through the back, thus giving trust more powerful than any other rocket to date. It’s also more sudden than any other.
October 11, 2008 at 3:13 PMwhat i meant to say was, “drill a small hole on the side and put a fan in the hole to suck air into the cylinder”.
October 20, 2008 at 1:51 PMi’m trying to do a science project on what you guys did. you are pretty awesome and i was wondering if you guys had any tips for me…
January 14, 2009 at 10:51 AMyes could be have a right function may be using a more powerful motor, light weight, may be same to a motorcicle motor and a right guide system i found this http://www.youtube.com/watch?v=vyb6vnX1My0 is a proyect same. but is same a “pinguin helicopter” and baxter low weight (joke) i like to much this chapter
February 27, 2009 at 3:32 PMThanks for doing pyrimid power ’cause I needed a science far project ASAP and it worked out perfect I got first place!!!!!!!!!
April 18, 2009 at 12:19 AMI love your show. I hope you still have Your “jet pack” I do believe that it can fly. 1) You must first use a propeller, like the one on a WW2 mustang P-51. Not that thick fan. 2) The Pitch of the propeller was too shallow. It should have a deeper pitch. Should add 5 to 10 degree angal or same as the mustang prop. at least. 3) Should add a ring or a band. Like the Mercedis Benz emblem. at about 1/8″thick or less. in the ducks. cut out a slot where the ring would fit in flush and the propeller could flow freely and not loosing air pressure. Allthese changes should make if fly. If it does would like to see it up close and personal.
October 24, 2009 at 7:00 AMSorry Didn’t finish my comment. I do have more ideas. But never get the chance to work on any of them. I also have an idea to go green and long distant on this type of flying. Please, I would like a reply. Thank you for your time. Again, I love you show. your fan: Delmer Delmer
October 24, 2009 at 7:25 AMsomeone did not research enough!!! all pyramid power testing must be done away from all metal structures. they did theirs in a metal building! oops! do not use a metal frame. use wood. place objects 2/3 up from the base. re-visit this one! try honey in a small plastic container(parts cabinet drawer works well)longer tha it is wide. put a control outside pyramid. leave several days. gets thick. control stays normal. they didn’t look before they leaped!! need more info, contact me.
October 24, 2009 at 10:53 PMI tend to agree with bennie dodd but I have some other stuff to say about this “myth”.
If you’re going to test “pyramid power”, you really should follow the “pyramid power” rules. It’s great that you made a scale model of the great pyramid, but that’s just the start. You then have to align one side of your pyramid to magnetic north using a directioanl compass. You also cannot have your pyramid in the same room as electronic equipment. They don’t get on very well, and your pyramid won’t work. When you’ve done all this, you should then leave the pyramid alone for at least 3 to 4 weeks. It’s a comsic battery and like any battery, it needs time to charge. You also should not bump or knock the pyramid at any time as it’s a very sensitive device. I’m not sure about the metal structures. I don’t recall all the details, but I was dissapointed with the pyramid power episode. I felt you guys didn’t give it a fair shot. You got a couple of half good results and said “busted”. I also think that sometimes you guys keep doing “myths” until you get the results you’re looking for and then say “myth busted”. If you think I’m crazy, please let me know, I’d be interested to hear from you guys.
Cheers, Martin
January 2, 2010 at 5:47 AMThe propeller fan jetpack should work in theory but it would cost more money than an average person could afford. An engine that is light enough and powerful enough must be found and even then it should be turbocharged or something to increase the power with little extra weight. A small jet turbine for micro model jets could be used to drive the fans. they are light and powerful, the excess thrust from the engine could be forced downward to get a few extra pounds of thrust.
As for changing the gearing of the engine and fan it would not work. A small engine doesn’t have the torque to drive the fans – Imagine trying to accelerate in a manual transmission car from a stop in 5th gear or two drive a school bus with a weedwhacker motor. Simply not enough power for the load being put on the engine. It just isn’t possible.
The cowling could be redesigned to generate more lift perhaps.
A commercial company could invest and create a personally jetpack and market it for 50k or something. A full scale comany would have the resources to optimize a design like this.
January 13, 2010 at 10:23 PM