This is my second attempt at a pop pop boat and even simpler to make than the first one. For the boiler I used an air freshener metal refill capsule. I think it is aluminium, it is certainly quite a soft metal. I made sure it was empty before I started working on it by discharging it in my sink so that I could wash away any remains. Please read the warnings on the instruction label as mine warned of flammable and irritant contents, so you dont want to do this near a naked flame and you dont want to get the contents on your skin or in your eyes.\r
I drilled a suitable hole straight through the existing plastic valve and found it made an air-tight fit for my drinking straw. As I am only using 1 straw for the exhaust I realised it would not be possible to fill the boiler with water by pouring water straight into the straw as there was nowhere for the air inside to escape, so I pushed a second thinner straw inside the first straw to squirt the water in and the air escaped through the gap between them.\r
The hull is made from a fruit juice carton or tetra pak as they are commonly known.\r
The boat is virtually silent compared to normal pop pop boats because the boiler does not expand and contr but the principle is the same. \r
Water in the boiler is turned to steam. The steam has a greater volume than the water so it pushes out of the boiler and down the tube. In the tube it cools, condenses and contrs so it is drawn back into the boiler and the process repeats. The ion of the steam pushing into the tube pushes the existing water in the tube out the back and that drives the boat forwards. The steam condensing and contring draws water back into the tube ready for the next push.\r
If your next question is why doesnt the boat oscillate backwards and forwards due to this push-pull effect? try blowing a candle out and then try sucking a candle out and you will see the blow is fairly directional but the suck is not.\r
If you watch the video closely you can see the water moving in the straw.\r
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Components\r
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Fruit Juice Tetra Pack carton\r
Air Freshener metal refill capsule\r
2 drinking straws, one thinner so it fits inside the other\r
Small amount of Blu Tack\r
Sticky tape\r
Tea light or candle\r
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Tools\r
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Drill\r
Scissors\r
Hobby Knife\r
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Here is Leo Spruchs version \r
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In response to some of the comments received since I uploaded this video I suggest that if you want some history on Pop Pop boats you look at this Wikipedia link on the subject they have been around since at least 1891 when a patent was filed by a Frenchman named Thomas Piot. \r
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HOW DOES IT WORK?\r
Water in the boiler is turned to steam. The steam has a greater volume than the water so it pushes out of the boiler and down the tube. In the tube it cools, condenses and contrs so it is drawn back into the boiler and the process repeats. The ion of the steam pushing into the tube pushes the existing water in the tube out the back and that drives the boat forwards. The steam condensing and contring draws water back into the tube ready for the next push.\r
If your next question is why doesnt the boat oscillate backwards and forwards due to this push-pull effect? try blowing a candle out and then try sucking a candle out and you will see the blow is fairly directional but the suck is not.\r
If you watch the video closely you can see the water moving in the straw.\r
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Here is the link to DaveHax tutorial which I found excellent \r
sciencetoymaker has a full step by step tutorialon putt putt (pop pop) boats starting in January new with1 here \r
Here is a good video on tweeking the speed of these boats \r
Daryl Foster devotes his channel to Putt Putt boats and here is the first one on his channel also back in new \r
My Pop Pop boats playlist is here \r
Here is my Toy Boats playlist \r
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I have thousands of videos on YouTube covering a wide range of subjects. To find them follow my search guides or or see my playlists page \r
Generally my projects are for my grandchildren to enjoy. OK, I enjoy them too. If anybody else likes them, that is a bonus. I like to keep my work as simple and basic as possible so that it can be copied easily and improved by anybody who wants to try themselves. I recycle or repurpose items rather than buy new and when I do buy I like to keep it cheap.\r