Air Date: October 18, 2006
A compressed air cylinder can blast itself through a concrete wall.
confirmed
Once the MythBusters constructed a launch tube and perfected shearing off the cylinder’s valve, the cylinder shot entirely through their constructed cinder block wall and damaged the solid concrete wall behind it. The MythBusters were also aware of recorded instances of such a thing happening.
A compressed air cylinder can power a speedboat.
busted
The two cylinders could only propel the boat 120 feet at a maximum of 5 knots. A second attempt resulted in the boat barely making half the distance, and barely registering any speed at all. It was jokingly said that Jamie could swim faster than the boat and that the speed should be measured in "miles per day" rather than miles per hour.
An engine can run on gunpowder alone.
busted
Even though gunpowder has a greater energy density than gasoline, none of the three historical designs worked for more than one cycle; the team could not find a practical or reliable way to feed the gunpowder into the engines (Most likely because black powder is not a liquid and therefore is not transported as easily). They were also unable to convert a modern lawnmower engine to run on gunpowder.
Regarding black powder not being a liquid:
June 23, 2007 at 8:48 PMIt’s not essential for it to be a liquid for it to flow. It only has to be a fluid.
Many powders & cereals are transported around factories using pipes & air to transform them into fluids.
I seem to recall incidents of explosive powders in factories due to the air/powder mix & static (flour/custard/etc). The mix is due to using a gas to transport them.
Robert H. Goddard, the father of liquid rocketry, found this out and invented liquid rockets in the process.
June 23, 2007 at 9:09 PMI agree with Martin on this one. Just because they couldn’t figure out how to do it, doesn’t mean it couldn’t be done.
I see no reason why the gun powder couldn’t be fed in using forced air. A simple venturi with enough air flow would be enough to pick up gun powder. The tricky part would be doing this while maintaining the right fuel/air mixture.
June 24, 2007 at 2:47 AMSpose, but what about longevity? Wouldn’t the residue build up quite quickly, making a motor ineffective? Sure there is residue with fuel, like petrol, but this is an oil-based, isn’t it? The remnants of the gunpowder would require some form of lubrication, or some super-hot burning engine. Anyway, it isn’t my strength.
June 26, 2007 at 10:35 AMRay has it right, the real problem with a gun powder engine is the build up of soot, LOTS of soot. Any combustion chamber you use is going to have to be cleaned continuously as the engine runs. The external combustion engine was probably the best route, and it has it’s own set of problems.
July 3, 2007 at 12:59 PMI liked the air cylinder rocket, but think the ‘busters missed a great opportunity with the speed boat: a hig-pressure bottle-rocket.
Thrust is governed by momentum change (not something to “thrust against” as suggested by Jamie), so using a liquid of 1000 times the density will dramatically increase the thrust. (Think about a bottlerocket with plain air vs water.)
I want a revisit!
July 19, 2007 at 1:44 PMyou mix the gunpowder with alcol and insert it into the engine
September 27, 2007 at 11:21 AMif u wud add gun powder with air as martin said the engine is highly able to explode because air wud be runnings faster and there low chance of the air/gunpowder mixture to reach every cylinder with proper equal quantity, which cud cause malufuntions in the engine…. it can be done surely but with very low oppturnities and mixing it with alcahol wil cause it to become wet which wud have very very low chance to burn, only the alcahol wud certainly burn but the gunpowder wud slowly start collecting in the engine and block it completely
October 3, 2007 at 10:27 AMWell, any machine gun or automatic gun is indeed a gunpowder engine. You already have the slider on the reloading mechanism. If one adds a weil to it, we have a engine in the traditional sense.
December 12, 2007 at 12:30 PMI am a Safety Manager in the indutrial construction industry. I am a huge fan especially the air cylinder rocket thru the wall. However, I noticed on some of your shows, you use a waist belt for fall protection in a lift. Unless Cal. Law is different, you guys should wear full body harness and tie off to the anchor points in the lift. I am stating this so you guys do not get hurt in the case of a fall or tip over. Keep up the good work.
December 27, 2007 at 11:07 AMReference the air cylinder rocket, I believe you need the release of the compressed air acting on a type of propellor to harness the energy sufficiently enough to generate forward motion. The cylinder would replace the engine on a conventional motor propellor, with the compressed air acting as it’s fuel. All motorised boats use propellors in one form or another, as it is the only effective way to generate forward thrust.
February 12, 2008 at 2:11 PMBy placing the exhaust of the air cylinder rocket underwater, it limited the force with which the air could leave, thus weakening the rocket effect… if revisited, keep the exhaust above the water line and HOLD ON TIGHT!
February 14, 2008 at 6:07 PMThe piston style black powder engine may be plausable. I believe the reason it didnt work was because the reloader was to fast to allow the powder to fall in to the firing chamber and residual pressure in the cylinder blew the powder up and out.
March 19, 2008 at 12:19 AMJust a suggestion: try a valve (similar to a ball valve) that rotates/ratchets one direction half a rotation per engine cycle. But the ball part of the valve, where it would normally be open and straight through, you would have to block it right in the center creating two small cavities(ONE POWDER SIDE ONE CYLINDER SIDE) for the powder to fill one at a time when the cylinder is firing. Near the BOTTOM of the stroke, the on the way down the valve would be rotated half a turn(through the one way ratchet and simple mechanical action of the cylinder)alowing a specified quantity of powder to fall on the igniter at its leasure. NO BLOW BY INTO THE POWDER RESIVOIR AND NO ISSUES WITH THE GRAVITY TYPE VALVE THAT YOU USED OPENING AND CLOSING TO QUICKLY. If you have questions about timing or the valve in general Ill be glad to draw it up for you.
Gunpowder cannot be used instead of gasoline, but can it be used instead of a spark plug?
March 25, 2008 at 12:37 PMWould the gunpowder be used, in reasonable quntities, to create enough heat to ignite gasoline?