Last Pop Pop boat in this series PUTT PUTT WORLD ENGINE 2 days ago   14:35

Last Pop Pop boat in this series for now. I hadn't intended to do this boat but I was in the garage and spotted the bag with the aluminium pipe had the original label on it telling us what it was.
Daryl Foster's LAST pop pop boat video

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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.

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 contracts so it is drawn back into the boiler and the process repeats. The action 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 contracting draws water back into the tube ready for the next push.
If your next question is "why doesn't 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.

Daryl Foster devotes his channel to Putt Putt boats and here is the first one on his channel also back in 2009
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Here is the link to DaveHax tutorial which I found excellent

sciencetoymaker has a full step by step tutorial series on putt putt (pop pop) boats starting in January 2009 with episode 1 here

Here is a good video on tweaking the speed of these boats

This link that explains the general annealing process without getting too technical and here is a YouTube video on the subject by George Goehl

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Comments 24 Comments

PeeJay Play
You can blame Atomic Shrimp for me lurking here ;) Subscribed and I’ll travel through your videos :)
Atomic Shrimp
I made the first prototype of my new pop-pop motor design (inspired by watching your series on these boats) - I'm aiming for a design that doesn't need any additional tubing - it sort of works (pulses and moves, but no pop-pop at this stage).
CasualAngle r
can it be made rc?
Doc Ink
it seems like it wants to run along but the bath is too small to get going, if the coil was closer to the candles it might heat better but they could melt faster
thehappylittlefox aka benji
good one I was wondering when you were going to make one with a coil ! perhaps for another time you can make one using some thinner copper pipe if you can find some I think mine came from an old central heating boiler ?
wozers . good floater there grandad .
John Bridle
Word on the street is that some military submarines use/tried similar propulsion to minimise detectable noise. Nice to have an ultra simple engine like this to propel a dinghy, etc, heated by driftwood, but general consensus is that this system does not improve by scaling up. Has anybody tried to do this? I did read of a late entry in a boat race which turned out to be a hoax.
Mike Flight
Another good build. I wonder if you covered the top of the spiral with a tin lid if it would retain more heat?

If you are ever trying to get the aluminum tube in a tighter spiral try filling it with fine dry sand and it won't buckle in the middle. The wire inside could be handy too because it may be nichrome wire and can withstand high amps. They use it to cut foam parts. :D

Just remembered that you have used nichrome wire in some of your other videos. :D
RC Lover san
Fridge replacement parts :-)
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PUTT PUTT WORLD ENGINE Last Pop Pop boat in this series 2 days ago   02:27

This is a test to see how fast the engine can move itself without a boat. It has to do with the velocity of the water jet. It is not a boat. A follow up video, Maybe World's Fastest Putt Putt Boat" is at Both should be watched prior to quibbling.
Other interesting things at