Talk:Pop pop boat

Construction

hello!!! anyone know how to make a putt putt boat EASY and FAST?!?!?!? —Preceding unsigned comment added by 137.88.136.71 (talk • contribs) 2007-03-14

One of the external links in the article has detailed instructions on a simple boat you can probably make with a couple hours of labor and a day to let glue dry. =Axlq 04:22, 8 August 2007 (UTC)

Pop-pop boat in popular culture

Don't know if one instance is sufficient, in the 2009 Hayao Miyazaki movie Ponyo. —Preceding unsigned comment added by 216.82.142.13 (talk) 00:56, 31 August 2009 (UTC)

Should flash steamer really redirect here?

After reading Experimental Flash Steam" by Benson and Rayman I'm led to believe that flash steamer historically refers to a steam powered vehicle which uses a Flash_boiler/monotube boiler. While pop pop boats are usually considered to utilise very simple flash boilers, but would it not be more verifiable for the redirection to point to the boiler concept ? steve10345 (talk) 02:18, 12 March 2010 (UTC)

You're right. Except that "flash steam" is also distinct from monotubes and steam generators (the boiler is heated dry, then water is pumped into it - monotubes are heated wet) Andy Dingley (talk) 09:38, 12 March 2010 (UTC)

Cluttered images

I put back in two of the images that were taken out in the last edit to reduce clutter. These images are important (IMHO) to understanding the different types of engines used in pop-pop boats. I do have to admit that the images do look a bit cluttered. If anyone can arrange them in a way that looks a bit more presentable but still gets the point across, please do so.

It would also be nice to add in the other images removed, just so that there are more examples of pop-pop boats in the article. Again, this must be done in a way that isn't so cluttered though. Images of different types of boats would be helpful as well, especially an image of the typical Boy Scout style of boat (wooden hull, coil type engine).

Engineer comp geek (talk) 05:35, 25 June 2011 (UTC)

Work of Thomas Piot

The article currently claims that Thomas Piot received patents for pop pop boat designs in 1891 and 1897. I can only find the 1897 patent online, and it is definitely not for a putt-putt boat, because it involves a valve, and the water flows in through one tube and is ejected via another. See: [1]. In other words, that patent is for a pulsejet engine, but not for a valveless pulsejet, like the pop pop mechanism.

The image that is claimed to be from Piot's 1891 patent does look like a pop pop boat design, though. I would very much like to see the source for that image and, if possible, the rest of the patent. The other images should also be better sourced, to make sure that the sources given for them are correct.

I recently checked Basil Harley's Toyshop Steam, published in 1978, and it says that the earliest pop pops that he's aware of were produced in Nuremberg by toymaker Ernst Plank before WWI, and marketed as "toc toc" boats. There is no mention at all of Piot or anyone else in the 19th century. The current claim in the article about a "similar boat seen in a French journal from 1880" should be documented. - Eb.hoop (talk) 00:43, 10 March 2012 (UTC)

I found a scan of the patent from 1891 here. It is indeed for a pop pop boat design, since it has no valves and water flows in and out through the same tubes. I insist, however, that the second patent, from 1897, is not relevant to this article. Also, the claim about B. Harley having seen a design for a "similar boat" in "a French Journal from 1880" should be either documented or removed. Harley's Toyshop Steam says nothing about that, or about Piot. - Eb.hoop (talk) 20:05, 10 March 2012 (UTC)

Principle of operation

I believe this paragraph to be totally mistaken:

The operation of the pop pop boat may seem surprising, since one might expect that if water is going in and out through the exhaust tube, the boat should merely shake back and forth. But while the water pushed out carries away with it momentum, which must be balanced (by Newton's third law) by an opposite momentum on the part of the boat, the water sucked in quickly impinges on the boiler tank and transfers its momentum to the boat. The initial reaction force on the boat (which would pull it backwards) is therefore cancelled by the pushing of the water when it hits the inside of the boiler. The result is that the inflow of water causes no appreciable force on the boat.[11]

The boat is moving forward at V and takes in water at rest, accelerates it and gives it a forward speed V. The water does not transfer any momentum (which it did not have in the first place) to the boiler or boat.

What makes the boat work is that the water is expelled with much greater V than it is taken in. If both speeds are the same with respect to the boat then indeed, the boat will not work. But if it is moving at V, and therefore imparting V to the water it takes in, and then expelling it at K*V it means the net effect is pushing the boat forward.

The notion that the boat can expell the water at the same speed at which the boat is moving forward (and therefore the water is at rest with respect to the earth) is clearly nonsense. GS3 (talk) 06:37, 10 April 2012 (UTC)

The boat does not need to be moving forward with any particular speed for the propulsion to work. It can start from rest and be accelerated by the net difference in force exerted by the outflow and the inflow. You can also take a putt-putt boat, hold it in place with your hand, and feel the forward pushing.

Also, it's not true that the water flows out faster than it flows in. If that were the case, then either the boiler would soon be depleted of water, or the inflow would take a considerably longer time than the outflow. But it is known experimentally that the inflow and the outflow each last for half of the cycle of the pressure in the boiler.

The explanation as summarized is correct, and explained in detail in the references given. See also the Feynman sprinkler. - Eb.hoop (talk) 03:17, 11 April 2012 (UTC)

I've seen and heard several explanations of how the pop pop boat works; all different and some more convincing than others. They usually start off by saying "this is how it actually works and all other explanations are wrong." I don't know the answer myself but I suspect that they are all correct to an extent and the end result is the combination of several small effects. --Roly (talk) 12:01, 2 May 2013 (UTC)

How it works

The steam engine that drives this toy works like that : before heating the boiler, water enters the submerged pipes until water surface level. when steam is produced, the pressure pushes this water columns. now, the reason why water is sucked back in is indeed the negative pressure that occurs in the boiler, but the correct reason is not the inertia of water columns, but the fact that the steam inside the pipes gets in contact with the cold walls of the submerged section of the pipes. It will instantly condense and this produces the negative pressure. Same mechanism like crashing metal barrels with vaccum produced by steam condensation, one of the forgoten steam engines force (besides positive steam pressure). I saw this in a movie where someone built a glass boiler and pipes and could clearly see the oscilating water column in the submerged section of the pipes. Many people try to scale up this engine - make a pump with no moving parts. With this insight, a better design for scale up could come.

Why the boat moves forward ? I still believe in the fluid dinamics of pushing a jet versus sucking molecules from 360 degrees directions - most of them canceling inertia before entering the pipes - I will test this with a cone - trumpet like - pipe ending - should make the boat much slower. — Preceding unsigned comment added by 2a02:2f02:102:bc00:7524:e212:86b7:394d (talk • contribs) 17:29, 15 June 2022 (UTC)

Principle of operation is wrong

As demonstrated by making a pop pop boat using a glass boiler and glass tubing (see this video) the water does not, in fact, go back into the boiler after being ejected. Rather, an oscillation is set up in the tube itself.

The whole first paragraph of the section is totally unsourced, and because it's wrong anyway, it should be replaced by the better explanation in the video, even though it might constitute original research. ~Anachronist (talk) 18:38, 20 September 2023 (UTC)

One of the weirder things about the last twenty years is that quite often YouTube science people will actually now put their references in their long descriptions, everyone having been so used to getting tagged for {{citations needed}}. :) I'd be happy with a heavy rewrite here, given how much of this is personal recollection or spun out of thin air. Chris Cunningham (user:thumperward) (talk) 12:32, 12 October 2023 (UTC)