A New Design of Pop Pop Putt Putt Boat Motor
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- เผยแพร่เมื่อ 9 ก.พ. 2019
- I've been inspired by watching GrandadIsAnOldMan - making pop-pop boats out of aluminium cans and tubing from a freezer defrost element.
It made me wonder if I can make a pop-pop engine without the tubing - well, that is, manufacturing the tubing by embossing it, using Drink Can Tinwork techniques.
It was a moderate success, for my first attempt!
Check out Grandad's channel here - if you do go there, please let him know Atomic Shrimp sent you!
/ grandadisanoldman - แนวปฏิบัติและการใช้ชีวิต
There’s always something new he’s tinkering with. I wish I had the imagination to make such things. Such a fun channel to keep tabs on
Thanks! Don't put yourself down - I bet you have ideas you could explore - you probably don't get the ideas at a moment when you have the time to try them out. All I do is write them down when they come into my head- then if I am ever bored or have free time, I always have something to do
I'm not an expert in fluid dynamics, but I like to pretend I'm one in the youtube comments section.
Your explanation is bang on.
I never knew Ricky Gervais was so crafty!
This has to be one of the simplest forms if these 'engines' I've seen... Truly conforms to the kiss principal.... excellent video mate ...
I'd say it's not especially simple. It's just very _practical or cheap_ A simpler design would be a single piece of tube coiled up in the middle for the boiler, or even a single piece of tube with one end closed off, and not even necessarily coiled. This way there's nearly no work involved in construction, and also the whole "assembly" is just one single solid piece; no real building process at all short of bending it and attaching it to the boat.
If you wanted to make more than a couple engines of this design, I'm thinking it would be worth carving out a form to emboss the metal into, and then serve as a clamp for the glue up.
What.. like the ends of the cans.. there's a thought aye.. not much appreciation of the physics in this designs
In my first year of art-school in my 3D foundations class we had to make pop-pop boats for our final assignment. They had to be able to work properly and look aesthetically pleasing.
I had never heard of pop-pop boats before my assignment, and it was hell to make one that worked well, but it was so peaceful letting all of the boats go in the pond on the last day.
I wish I could have watched this video when we were researching them. I like this design!
I remember these. They are called "impulse engines" in Star Trek.
Damage report Scotty! Aye cap'n, impulse engines are inoperative. Lt Uhura is having a relaxing bath and she's taken all the tea lights.
@@ferrumignis lol!
Which is why they are designed to look like the starship Enterprise.
@@ferrumignis LOL! That explains a lot!!
I like the shockmaster photo lol!!!
The rattling sound of the aluminum can on my tablet was driving my wife insane, so I cast it on our big screen tv and watched it thru amplified speakers!
She hates you!
Robin John it’s been 3 months, I’m sure he’s still sleeping in the shed
@@hand13932 Sleeping in the shed is living the dream.
Jerk.haha
@@hand13932 I’m really glad that I installed central air and gas furnace in my shed!
Love this channel. Has a little of everything.
I think the copper wire one is a bit cooler, but first time seeing a "pop pop" very cool
Love the impression-molded technique for stamping both the steam chamber and jets out of a single piece!
Your design is very simple as all the best designs are, thanks for sharing this I found it extremely interesting.
We used to make these with small inverted oil cans. The oil reservoir made a perfect little boiler over the candle and the stem sticking down through the boat, made a great thruster.
Should make a pop pop boat with a rudder and a magnifying glass for heat from the sun.
That's an interesting idea!
The weather we had today, that would work. I think I' nip outta my workshop and k ock one up.
I was just thinking about making one using a light plastic magnifying lens, You stole my idea?!
Is it really more efficient to have the asymmetrical tubes though? yes it provides a "nice" flow, but might that flow be detrimental to efficiency? It would probably not heat the water enough to be forcefully expelled out with high energy, and that lower energy expulsion seems to me like it might be less effective to counter the intake/suction forces.
Nice voice. Could easily do radio
I have made dozens of pop pop boats, and they have all had equal length tubes and they work fine. I have even made a couple with a single tube and they also work, but not as vigorously.
I have a doming block and punch set just itching to be used to make this, You dont use them often but when you do you're always happy you have them!
Hey, top man, thanks for the shout out. I have had several extra views on my channel as a result. Fascinating idea to emboss the aluminium, certainly not an easy option but at an industrial scale I am sure they could punch them out with a big press.
It's not a bad idea. With 3 sheets of aluminium. 2 for the chamber and one that you could attach to the underside with a coil of kanthal or nichrome wire attached to a battery. You could effectively have an electric put put boat with the heat provided via an electrically heated coil. ........maybe a future project to one up Mr shrimp 😁
It's an intriguing idea. I wonder if that would be more efficient than just driving a small motor...
@@AtomicShrimp I think the power we need to achieve flash heat for the water to turn to steam on contact for full efficiency might be an issue. Probably one of those "unless you try it you never know" unless you are good at maths which I am not. On a side issue I just followed your Teespring link for the T Shirts and wasn't sure if the descriptive text was a continuation of the Scam Baiter English theme "This high quality a shirt is be does offer comfort and style and has be done having an double-stitched seams with doing having has tailored fit and has why a do done inbuilt taped seams for because does strength and doesn’t ripping?" I am sure it is but too subtle for me to grasp at first viewing 😍👍 got there in the end.
@@AtomicShrimp It was probably the "Inventior" on the mug that threw me
@@GrandadsOtherChannel I didn't even notice that! - it's supposed to say Invention (the image has been cropped
18:52 I love how you said “engine” I love it so creative ❤️
Anyone here just for the pretty colours not having a clue what's going on?
You need a step down from water storage to jet system. But great effort mate.
The thermodynamic forces complement the mechanical influences for added thrust.
Congratulations for a totally new and what would look like at a first glance something that would not work. Your video is the very first of the many that actually explains in the very simplest of terms as to why the boat moves forward.
This may not be rocket science but to be able to understand and explain the working of this infact water rocket engine deserves appreciation. Good on you.
Cool nice idea you could try making the top part slightly larger and folding it over the edges might seal it but a bit tricky doing the round bit though !
Black Bodge-tape before marking out! Haven’t seen it in years...
Cool stuff man, I've never seen a hydrodynamic pulse jet before.
crashnet
Very cool. If you punch a hole between the tubes near the boiler (have to get both edges to seal well) and narrow the rims as much as you dare, then it may keep more of the heat in the boiler... I thought the foam was going to end up melting!
You must have been the funnest dad ever for your kids! 😀
To flatten the can-sheetmetal, just put it between two sheets of paper and iron them (temperature set to cotton). They'll stay perfectly flat after that: The paint on both sides loses its rigidity while being heatet and cools flat.
Neat idea! (Am I the only who was waiting for those matches to get knocked into the tub?)
I only noticed how precarious that was when I was later editing the video!
Based on Steve Mould's glass pop pop boat demonstration, it looks like your explanation of the mechanics of the simple pulse jet engine are not exactly correct. It would be fun to see you revisit the simple engines subject in a new video!
I wanted to rag on you, but this is totally genius
anxiety is a box of matches on the edge of a full tub.
Fun build, thanks for sharing.
your next goal should be to make a V-1 replica.
I can't help wondering if an arrangement with one wider tube facing forwards and with a one way valve fitted, wouldn't vastly improve the efficiency of the motor..
Upside down newspaper reads : activities for older people at the (something or other) centre. Haha. They could be making boats, opening cans/boxes, foraging, etc. Your wife is thinking "I just cleaned that tub".
Yes! Superb! A new upload! Hope you're doing well :)
A stealth pop pop boat then?
NIce video. If you make a forum out of wood, you can trace the alum. into it, giving you a better/faster engine design
Cool video! I've never seen a pop pop boat before this thank you.
You're like Senku from Dr. Stone. You're brilliant!
The future of marine propulsion!
This is kind of like Art Attack for grownups.
I loved watching Art Attack (and SMart) with my kids as they were growing up
@@AtomicShrimp Art attack was a great show. My sisters and I loved it when we were kids.
That was fun.
The only thing I would do differently is? - place the painted sides inward. It might help in epoxy grip, to make it more even, like the paint. I know; may not last as long, if the paint pulls away or heats up too much.
I knew you watched Grandads an old man😀 He has a similar sub count to you but is struggling a bit with views so cool for you to shout him out.
He is so good at tinkering with powered toys - he deserves more attention for that
Me: might as well go on TH-cam.
TH-cam recommendations : watch this guy make a pop pop boat
😂poundland! Sounds like somewhere you’d take a tinder date.
Ironically, it is just that!
We commonly call this sucking but in fact it's another kind o blowing.
-
AtomicShrimp
Feb 10, 2019
,
20:36
8:43 into this and strangely find myself wanting a Strongbow!
Thanks Clive!
Hi Shrimpy. Great video. I thoroughly enjoyed it. In actual fact this is not a new design. My great grandmother and I used to make these when I was a tiny kid.. oh such memories. That was over 60 years ago.
Nevertheless a great vid. Thanks mate.
Innuendo seems to go well with an English accent. Classy.
Honestly, none was intended. I merely wished to demonstrate how one could erect a device that by blowing and sucking, would generate thrust in order to penetrate the water
Metal knob art
If you listen to it quietly. You can hear the little Pop pop noises..
Next wierd stuff in can should be *"vegetables"*
What's weird about canned vegetables? Beans, peas, tomatoes, potatoes, corn… Pretty typical.
@@user-vn7ce5ig1z vegtables are wierd there so stinky wierd and even H E A L T H Y
@@blueeyedblondhairedo5879 I did actually have a can of 'canned pickled vegetable' lined up (that's all it said), but when I checked the date, it was very, very expired
@@AtomicShrimp oh also im curious when your next scam baiting video will come out im so excited
Ha ha he told you!! 😜😜 they have slepping bags in cans!!
m.th-cam.com/video/OO2CplYD03Y/w-d-xo.html
It's a long time ago and you may no longer read comments but I think (and I note some doubt in your mind too) that you're wrong about how these work.
I had one just after the War - both pipes were the same length. It had a thin domed diaphragm which had two stable states - concave and convex like the 'clicker' in a toy frog. My father (who was an engineer) and I both thought the effect was caused by the heat causing the diaphragm to flip state but it was hard to see how this would result in continued operation - also other people have made motors without this diaphragm.
You touched on what I believe to be the mechanism - the heat causes a steam bubble to form, expelling water from both pipes as a jet but also creating a vortex in the boiler so the bubble is collapsed by cooler water drawing water in from both pipes but not, as you say, as a jet.
I don't doubt there is a jet being expelled from both tubes, but the uneven length results in net circulation, that probably contributes to long running without just boiling dry
@@AtomicShrimp Thanks for taking the trouble to reply. I beg to differ on your 'different length pipe' hypothesis.
I think you hit the nail on the head when you suggest the expelled water jet was directional and so produced thrust while the aspiration of water in the negative pressure phase was not.
This is an intriguing phenomenon (I wonder who invented it !) and, I think, can be explained by nucleation (the thing you put anti-bumping granules in a beaker to prevent when boiling).
The steam 'bubble' produces a high pressure pulse which expels water and creates turbulence in the boiler which quenches it and aspirates an equal volume of cold water through he tubes.
I don't think you need your 'circulation' idea to prevent boiling.
Without a little net* circulation, the boiler can overheat and the process may stall completely. In practice, I suspect this happens even with equal length tubes, just because nothing is perfect.
*I'm talking about net circulation - that is, a tendency for imbalance, not a complete circulation cycle at each pulse
@@AtomicShrimp I understand your reasoning. Somewhere there's a video (sorry, don't have the URL) of a guy who made the boiler from a shoe-polish tin. The excursions of the lid are clearly visible and audible - it goes quite convex during the 'pulse' and then quickly concave (viewed from the outside) - a cheapo pressure transducer if you like. The volume change is quite dramatic and, I think, would displace enough water to prevent boiling dry without any additional circulation. Again I think you're dead right about a jet on the outward pulse and a non-directional suck back. Also it seems necessary to tilt the boiler upwards to make it cycle - perhaps encouraging a hotspot for nucleation with a reserve of cooler water below to quench the bubble. Someone commented that talking about how put put motors work is really at the Dark Edge of the Internet but it's definitely more interesting than cats on pianos and completely harmless !
All best wishes
Why does this get me excited?
Would it not be better to emboss both sides rather than just one and have the other side flat? I'm assuming a slightly larger capacity reservoir would increase the efficiency, or am I missing something obvious?
I'll come clean and admit that the two tries you saw in this video were not my first two tries. For my first attempt, I did try embossing both pieces - the embossing process does cockle the edges of the metal a litlle bit, and trying to get two wrinkly pieces to mate together was tricky.
I think if I was embossing with a die press, it would work, but when embossing by hand, there's a bit too much wonk in the pieces.
@@AtomicShrimp When you say "emboss", are you talking about the full scissor handle treatment? If so, then what about doing the second side with just the pen so that it's in about the condition seen at 2:53? I wonder if it might pop better like this than with the full dome treatment?
I'm thinking that maybe embossing the tubes on one piece and the dimple for the boiler on the other might be interesting. I may also try hammering out the boiler with a ball peen hammer on a sandbag, to get greater volume.
@@AtomicShrimp Another thought. You could anneal the metal locally where you want to make the boiler. This might reduce how much the rest of the metal cockles.
I did a very quick test, and it looks like it might help. A cigarette lighter probably doesn't put out enough heat to do much - but maybe it helps a little. A propane torch (plumber's torch) put's out plenty of heat - you need to be careful not to overheat and melt the aluminum.
Recommend you look up a tesla valve.
As you could make a template for it in layers and use your aluminium sheet embossing/cutting technique to create them.
Especially since you seem to have the patience and dexterity required.
I am going to use cans like you have done,but I am using a larger clamp and old steel knitting needles to keep the tubes clear,and using them to check/clear debris.
I then am planning to take the valve from an old innertube,to encourage a one way flow.....although the can boat is a lovely toy in its own right....
I can see how this would make a very very low power solar pump.
Question.Would performance improve if the parallel tubes were aligned vertically ?
Why not use the whole empty can as the boiler, and copper tube of 10mm inner diameter. Would that translate into a faster moving craft? Just wondering if that could work. Worth a try, and if it doesn't work, well, no harm done...
With a simple put put boat. It only has 1 concept. All you did was reduce the power, so it dosen't make a noise.
Very nice! Frankly, I didn't think it'd be possible to glue it neatly in such a way.
I don't believe the asymmetry's necessary at all, though, or that such a thing as "net circulation" really exists - I've seen symmetric designs work perfectly fine, without veering off to one side. This looks to me like it's just a vibration motor, similar to what you get by sticking a speaker on a brush.
Likewise, I din't think the "directional jet" explanation is entirely correct either - if we limit our view to within the tube there's no directional difference - like with brush motor, the reason to me seems to be that the water feels much less resistance coming out that it feels going in, so we have a reactive propulsion one way and a soft collision the other.
well explained !! Kids will understands... so will elderly do
I want Ponyo's putt putt boat.
Epitome of "mickey mouse" construction!
So, and I'm not sure on this so it could be completely wrong and not work at all, but what if a water "in-flow" tube was placed near the bottom (but not right on the bottom) of the boiler chamber then facing forward on the boat and then the propulsion "exit" tubes were placed slightly higher and opposite on the boiler chamber? Since heat and steam rise up would it create a situation where the propulsion tubes suck in less water, or none at all, and therefore provide more propulsion power since there's a separate way for the colder incoming water to come in or would it just not work at all?
Problems I could personally see with that would be that all tubes would still be trying to function even with the difference in height within the chamber thus working against each other. Or it could make it much more complicated to construct due to a need for some sort of directional control valves within the tubes....
At any rate, I'm just thinking here. As I said, I may not be completely understanding the science behind all of this and my idea here could be complete garbage....
So, the left pipe is short and the right pipe is long, and a flow is created so that more thrust happens at the end of the right (long) pipe, so shouldn’t the boat circle anti-clockwise in the bath? It consistently turns to the right...why?
I imagine irregularities in the shape of the boat are the most significant factor in directional stability
@@AtomicShrimp had me baffled!
What is that watch you're wearing?
It's the ziiiro saturn. I will be reviewing it soon...
@@AtomicShrimp thanks for the info, looking forward to it
Looks like beer from england.
I wonder if this could be done on a bigger scale to carry people?
I don't think it scales up. The engine works because of the expansion of single bubbles of steam inside the boiler - they are of fairly finite size
May I ask if anyone knows if you could create a pop pop boat like in ponyo that would run?
I don't think it will just scale up. These motors rely on effects that happen at a fairly small scale - in particular, the formation and expansion of individual bubbles of steam
Pop-pop-less boat
have You REALLY compared symmetric to asymmetric lenghth?
- I want proof before stipulation.
It's a stealth pop pop
I’m sorry I have to do it.
20:17 “lets start off by telling the difference between blowing and sucking.”
*shrimp introduces a shady lady with a questionable background*
>outro music plays over everything she says, video ends.
I figured I'd find this comment, when I got past 20:17
I think that you might have swapped which tube does more pushing.. The shorter one would give more thrust due to less drag by the pipe being shorter.. The longer the straw, the harder you need to suck for the same result kind of thing.. This is also supported by your boat turning to the right when the shorter pipe was on the left side. meaning it gave more thrust..
I think you're right. When I was trying to figure out the effects of the asymmetry, I tied myself up in knots a bit
@@AtomicShrimp Yeah, happens sometimes for me too.. Helps with a set of fresh eyes from the outside looking in.. :) Keep up the good work.. :)
Place it in a bath tub. Shout Pop Pop Putt Putt few times and just push the boat until the other bank of the tub. Engine trouble only, just need to push. Mission completed. Please apply for a patent immediately.
It works but is very inefficient maybe if you made the top side convex and the the bottom side concave it would be more efficient
agreed - the boiler wasn't capable of flexing/clicking in this prototype - and that does seem to make a difference to the thrust
I was about to Ask my mom if i could make one then i got scared of asking
Picked them up on the side of the road? What, do you not drink pop or something?
I don't get through very many canned drinks - the occasional beer (but most of the beer I drink is in bottles)
Huh. I guess that makes sense. Where I come from pretty much everybody drinks pop on a regular basis, and most people prefer cans because of the better taste, so there's always loads of cans in every trash can I see. Not just pop either. I remember when I was a little kid, there was a big cage behind the church where people dumped their cans to be recycled, presumably, and the amount of beer cans in there was hilarious.
Max Scott you're from the Midwest aren't ya?
Right in the middle of it
And it's free and cleans up the environment.
guessing the words push and pull never occurred..
I would have sliced my finger by now. Owwww!
just gat ta toobz
25:40 Will small valves work to lead water from intakes in the front and jets it out from the rear?
may need a rudder
OK
aaah, its a pulsejet. :)
shouldnt mix your drinks, you'll be sick lol
One comment, I have had a number of pop pop boats over the years and have two sitting on a shelf in the living room at the moment and both of them of them have the same length tubes.
OK, that's weird - I've only ever seen them with unequal tubes (do yours have the same length to run at the boiler end?)
Any sort of asymmetry should work. Different diameter nozzles, one tube lower in the water, the heat source might not be centered, etc... Also, they may have cheated and put in a flap or ball valve.
In a sink try running water in from one tube then the other to see if the flow is easier in one direction.
Finally, try it in a bathtub, see if it actually works.
I have a recent production (within the last 20 years) Chinese boat that has two tubes of equal length and equal diameter. There are no restrictions at the open end but I can't be sure about the boiler end of the tubes.
However, my dad has some older ones that were made in Japan. I think they were made in the post war (WWII) era, but I'm not sure. In any case, one of his larger ones (maybe 1 foot, 250mm, long) has only a SINGLE TUBE -- and it runs! The tube is larger. Probably 3/16 to 1/4 inch (5 or 6mm), but I don't remember for sure. In any case, I think it was large enough to let the air and water pass in the single tube when pre-filling the boiler, but we might have used a long thin tube plastic tube inserted into the metal tube. I have no idea if asymmetric tubes are helpful, but they are not required.
To make sure it wasn't just my bad memory, I just took my two-tube boat and did a test. I pre-filled the boiler with water (as is always required), and then plugged on tube with a small piece of closed cell foam. After adding the candle, it struggled a bit at the start and I thought it might quit -- but it didn't. After 30 seconds or so it ran happy for a few minutes until I stopped it. So, these engines can absolutely run on one tube. Two tubes makes them easier to fill with water (and may have other advantages).
Fun fact, the boat hulls (but probably not the boilers) of both my Chinese boat and my Dad's older Japanese boats appear to be recycled from (steel) cans. They all have writing on the inside of the hulls where it is somewhat hidden.
@@AtomicShrimp I made these with a vertical coiled tube the asimetry comes from one tube being lower so the tubes in the water can be the same length
@@andrewsnow7386 Well that destroys my theory that the symmetry is required. Perhaps it is beneficial.
The next logical experiment would be to make the tubes asymmetric and see if that improves the thrust. If it were my toy, and I liked it, I would lengthen one tube by wrapping some around the end and spiraling out a little. If the toy wasn't significant, then I would just shorten a tube.
20:14 lol can some one please place beeps in all the right place'es in this video.
I've never seen a pop-pop boat with asymmetrical pipe lengths. Are you sure that's necessary? I'm not sure that I believe it is.
Nevertheless, your next project should be a solar pop-pop with a computer-guided magnifying lens to focus the sun's rays on the boiler. When can we expect to see that? :) :)
I think the asymmetry is necessary to provoke a net throughflow of water - with exactly symmetric pipes, I think the engine may tend to stop running after a while, once all of the water inside it is hot or boiling (not that this would ever really happen as some small imperfection will always break symmetry)
I was going to suggest building a one-tube pop-pop boat to test out that theory, but GrandadIsAnOldMan has already built a single-tube pop-pop that does work. th-cam.com/video/ggF-iwb_ENo/w-d-xo.html In my seven and a half decades I've believed a lot of things that turned out to be untrue. Now I question everything I "know", because often what I think I know just isn't so.
Cans from the side of the road. Lol
Yeah, it's sad. I did a little survey of cans a few years back, to determine the favourite beverages of littering morons: atomicshrimp.com/post/2009/02/21/WDMD-What-Do-Morons-Drink
8:35 - You might not be as lucky next time. This would make a paper-cut feel like a tickle. Wear gloves!
13:35 - Did you start over from scratch? 🤨 Couldn't you have just plugged the leaks?
Yeah, this stuff is sharp at the edges - the worst is that the process of cutting with scissors tends to leave little needle-sharp whiskers on the cut edges.
I did think about plugging the leaks, but there were at least 3 of them and they were the result of clamping failure - second time around, I just used more and bigger clamps - I think it was probably la little less effort to start over, but not much in it.
The explanation is not really right - I'd recommend Steve Mould's video on Pop Pop boats. The tubes can be the same length and in fact, it could be just a single one to work. The sound originates from the flexing metal plates around the water tank. Cooking the epoxy above the flame might not be the best idea.
I do really enjoy your videos a lot and I have been watching for years now. Please don't get discouraged by my input on this video.
😂😂😂
Why so many dislikes?
I question the need for assymetrical tubes. I have just received one that I ordered through Ebay, and it looks identical to the one that opens this video ...
th-cam.com/video/g3OLhFx8KZY/w-d-xo.html
If you run the vid forward to 2:10, you can see fairly clearly that the tubes are equal lengths, and it works fine. On yours, because the tube is formed in a flat section, you have a paddle hanging down on the right side of your boat (see 19:28), and the boat runs in circles to the right.
The boat I got came with an explanation of how they work, but it was slightly different from your explanation. It says that as steam is produced, water is ejected out the back, and a boiler-full of water moving backwards causes the boat to move forwards (equal and opposite reaction, and all that). When all the water has been pushed out of the tube, steam starts to come out and is instantly condensed by the water in the pond, which is drawn into the end of the tube (or pushed by atmospheric pressure if you're a pedant ;-) and cools the steam it contacts, till cool water is drawn all the way into the boiler where the operation repeats.
Now, pop pop boats do, indisputably, work, but I still don't get why - and for several reasons.
1. If the boiler holds a gram of water, then when it is pushed out the back, it will cause a forwards impulse on the boat, but then a gram of water has to go in the opposite direction to fill the boiler again, which (as you noted) should cause a backward impulse on the boat. The explanation you give of what the water stream does after it leaves the tube (out directly, in from surrounding water) seems a lot like the explanation of rockets - that the exhaust gasses push against the air - but if that's how it worked, it wouldn't work in space. I find it difficult to see how the water that has left the tube can have an influence on the boat itself.
2. The little boat I bought has an oval boiler (see the clip of it right at the beginning), and the tubes enter it about the half-way mark, so that when I fill it, water will run into the part of the boiler below the tubes, leaving an air bubble about half the size of the boiler above the tubes - and it works fine. Before buying this boat, I made one, and I was careful toposition the tubes at one end of the boiler, so that I could fill it completely - and I couldn't make it work. Is the air bubble important?
3. When you first put the flame under the boiler, it takes about 10 seconds before anything happens - yet, when the boiler fills with cold water after the first impulse, that it heats up enough for the second impulse in - a twentieth of a second? I guess it's because the boiler temperature is already above the flash point.
Apparently, the boiler doesn't need a flexible diaphragm, and in fact, they are faster without one, though they don't make the characteristic sound. Consequently, the boiler can be a coil of tubing, with both ends taken out the back of the boat, and there is a Frenchman who made a glass coil and photographed it with a high speed (slo-mo) camera, but I didn't 'get' his explanation either.
Ah! - I just found an explanation on Wikipedia that may be it. Have a read of ...
en.wikipedia.org/wiki/Pop_pop_boat
They also refute the explanation of the water coming out as a jet, and being sucked in from all directions.
Sometimes, the explanation for the simplest of things can be pretty complex!
Those look to be different lengths to me. Looking at 3:40
@@AtomicShrimp I see what you mean. You get a better view just before that, at 3:33, but the difference in length looks like about 2mm, which, I think, is probably accidental. It's certainly much less than on the model you built. Also, note that one of the tubes has a bubble of water on the end of it. Also, the Wiki article says that they were originally made with a single tube.
On the boat I bought, which looks exactly like the one featured, the tubes are the same as well as I can measure. It would be an easy experiment to try - if you still have your boat, cut the longer tube off and see if it stops working.
It was a good video by the way - I intend to try your method.
BTW, this guy reckons that the more tubes that are attached to the boiler (within reason, I guess), the faster the boat goes. Look up his web site. He has made about 100 of these boats, and experimented with them widely. He also says they're faster without the flexible "put put" diaphragm.
th-cam.com/video/JOE3qIslu24/w-d-xo.html
I wasn't real happy about your explanation of the water flowing into the tube from all directions. resulting in little net force. It's true that the water flows in from all directions, but all the water flowing in ends up going up the tube in the opposite direction to the steam flowing out. The mass water flow rate into the tube is equal to the mass steam flow rate out of the tube and the velocity of the water is in the opposite direction of the steam. Momentum is the product of mass times velocity The momentum of the steam is greater because of its greater velocity and that's why the boat moves.
I get what you're saying, but I'm not altogether sure that the velocity is different on the two halves of the cycle though
Water Turbo..