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My Pop Pop is not so lively.....

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  • theo570
    Hey guys, I built my first pop pop engine (actully pot pop, later) and although she make a bit of steam there is nowhere near enough to push a boat through the
    Message 1 of 12 , Mar 28, 2011
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      Hey guys, I built my first pop pop engine (actully pot pop, later) and although she make a bit of steam there is nowhere near enough to push a boat through the water.

      Ater about 1 min 45 sec I get a steady stream of bubbles. This goes on for about 1 minute tops. I would guesstimate a bubble a second.

      Because it stops after a minute I think it is not drawing water... it is probably 3 vertical inches from pipe ends in sink to bottom of boiler... Pipes are still 10' or so long by the way (not fitted in a boat yet). Any ideas from the pros??

      Anyhow, the Pot Pop is made of .020 sheet copper that has been peened into a 1/2 inch nut. This leave me a nice bowl shape which I soldered a peice of .010 brass to. I added .125 copper pipes about 2/3 way down the bowl. Poics tomorrow.

      Thanks

      Ted
    • William Abernathy
      I suggest: Bigger fire. Thinner brass. I got similar performance out of mine (thin stream of anemic bubbles) until I added more candles. Jean-Yves s plans
      Message 2 of 12 , Mar 28, 2011
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        I suggest:

        Bigger fire.

        Thinner brass.

        I got similar performance out of mine (thin stream of anemic bubbles) until I
        added more candles.

        Jean-Yves's plans suggest that 0.05 mm (0.002") works well and that 0.15 mm
        (0.006") is too thick. I've used 0.003" brass sheet and it worked great.

        --William

        theo570 wrote:
        > Hey guys, I built my first pop pop engine (actully pot pop, later) and
        > although she make a bit of steam there is nowhere near enough to push a boat
        > through the water.
        >
        > Ater about 1 min 45 sec I get a steady stream of bubbles. This goes on for
        > about 1 minute tops. I would guesstimate a bubble a second.
        >
        > Because it stops after a minute I think it is not drawing water... it is
        > probably 3 vertical inches from pipe ends in sink to bottom of boiler...
        > Pipes are still 10' or so long by the way (not fitted in a boat yet). Any
        > ideas from the pros??
        >
        > Anyhow, the Pot Pop is made of .020 sheet copper that has been peened into a
        > 1/2 inch nut. This leave me a nice bowl shape which I soldered a peice of
        > .010 brass to. I added .125 copper pipes about 2/3 way down the bowl. Poics
        > tomorrow.
        >
        > Thanks
        >
        > Ted


        --
        William Abernathy
        Berkeley, CA
        http://yourwritereditor.com
      • theo570
        Test #2 perfomed MUCH better. I used the wifes cake dish, leaving the pot sitting over the edge outside. This kept the elevation between pipe openings and pot
        Message 3 of 12 , Mar 29, 2011
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          Test #2 perfomed MUCH better.
          I used the wifes cake dish, leaving the pot sitting over the edge outside. This kept the elevation between pipe openings and pot at less than 2 inches. Lit the candle and in less than a minute it started to bubble a bit. After that a shot of easter egg dye showed one tube sucking and the other pushing. Pretty solid push I might add.

          Still no 'POP' and as William pointed out my brass is just to thick.

          Next problem: It only runs for about 7 minutes and then quits making thrust?? When I remove it from the water it feels like the pot is only about 1/4 full of water?? How am I getting a run dry state?

          Thanks William.

          Ted

          --- In pop-pop-steamboats@yahoogroups.com, William Abernathy <william@...> wrote:
          >
          > I suggest:
          >
          > Bigger fire.
          >
          > Thinner brass.
          >
          > I got similar performance out of mine (thin stream of anemic bubbles) until I
          > added more candles.
          >
          > Jean-Yves's plans suggest that 0.05 mm (0.002") works well and that 0.15 mm
          > (0.006") is too thick. I've used 0.003" brass sheet and it worked great.
          >
          > --William
          >
          > theo570 wrote:
          > > Hey guys, I built my first pop pop engine (actully pot pop, later) and
          > > although she make a bit of steam there is nowhere near enough to push a boat
          > > through the water.
          > >
          > > Ater about 1 min 45 sec I get a steady stream of bubbles. This goes on for
          > > about 1 minute tops. I would guesstimate a bubble a second.
          > >
          > > Because it stops after a minute I think it is not drawing water... it is
          > > probably 3 vertical inches from pipe ends in sink to bottom of boiler...
          > > Pipes are still 10' or so long by the way (not fitted in a boat yet). Any
          > > ideas from the pros??
          > >
          > > Anyhow, the Pot Pop is made of .020 sheet copper that has been peened into a
          > > 1/2 inch nut. This leave me a nice bowl shape which I soldered a peice of
          > > .010 brass to. I added .125 copper pipes about 2/3 way down the bowl. Poics
          > > tomorrow.
          > >
          > > Thanks
          > >
          > > Ted
          >
          >
          > --
          > William Abernathy
          > Berkeley, CA
          > http://yourwritereditor.com
          >
        • Jussi Virtala
          Hi Ted You asked, How am I getting a run dry state? Water has always some air dissolved in it. This is the air fish breath. =)  But when you heat water,
          Message 4 of 12 , Mar 30, 2011
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            Hi Ted
             
            You asked, "How am I getting a run dry state?"
             
            Water has always some air dissolved in it. This is the air fish breath. =)  But when you heat water, the dissolved air evaporates. This evaporated air fills your boiler after a few minutes and your engine stops popping.
             
            When you let your boiler cool the trapped air contracts and pulls some water in to the boiler. So it seems it has some water in the boiler when it's cool, but actually it's empty when it's hot.
             
            Jussi Virtala


            From: theo570 <theo570@...>
            To: pop-pop-steamboats@yahoogroups.com
            Sent: Tue, March 29, 2011 7:35:39 PM
            Subject: [pop-pop-steamboats] Re: My Pop Pop is not so lively.....

             

            Test #2 perfomed MUCH better.
            I used the wifes cake dish, leaving the pot sitting over the edge outside. This kept the elevation between pipe openings and pot at less than 2 inches. Lit the candle and in less than a minute it started to bubble a bit. After that a shot of easter egg dye showed one tube sucking and the other pushing. Pretty solid push I might add.

            Still no 'POP' and as William pointed out my brass is just to thick.

            Next problem: It only runs for about 7 minutes and then quits making thrust?? When I remove it from the water it feels like the pot is only about 1/4 full of water?? How am I getting a run dry state?

            Thanks William.

            Ted

            --- In pop-pop-steamboats@yahoogroups.com, William Abernathy <william@...> wrote:
            >
            > I suggest:
            >
            > Bigger fire.
            >
            > Thinner brass.
            >
            > I got similar performance out of mine (thin stream of anemic bubbles) until I
            > added more candles.
            >
            > Jean-Yves's plans suggest that 0.05 mm (0.002") works well and that 0.15 mm
            > (0.006") is too thick. I've used 0.003" brass sheet and it worked great.
            >
            > --William
            >
            > theo570 wrote:
            > > Hey guys, I built my first pop pop engine (actully pot pop, later) and
            > > although she make a bit of steam there is nowhere near enough to push a boat
            > > through the water.
            > >
            > > Ater about 1 min 45 sec I get a steady stream of bubbles. This goes on for
            > > about 1 minute tops. I would guesstimate a bubble a second.
            > >
            > > Because it stops after a minute I think it is not drawing water... it is
            > > probably 3 vertical inches from pipe ends in sink to bottom of boiler...
            > > Pipes are still 10' or so long by the way (not fitted in a boat yet). Any
            > > ideas from the pros??
            > >
            > > Anyhow, the Pot Pop is made of .020 sheet copper that has been peened into a
            > > 1/2 inch nut. This leave me a nice bowl shape which I soldered a peice of
            > > .010 brass to. I added .125 copper pipes about 2/3 way down the bowl. Poics
            > > tomorrow.
            > >
            > > Thanks
            > >
            > > Ted
            >
            >
            > --
            > William Abernathy
            > Berkeley, CA
            > http://yourwritereditor.com
            >

          • Slater Harrison
            Hi All, To add to what Jussi has said, there is a good article by Jeff Bindon about pop pops engines in general, and specifically the dissolved air problem. On
            Message 5 of 12 , Mar 30, 2011
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              Hi All,

               

              To add to what Jussi has said, there is a good article by Jeff Bindon about pop pops engines in general, and specifically the dissolved air problem. On page 2, column 1 and 2 Jeff contends that a successful engine (one that keeps running) will periodically eject extra air. He didn’t use the word “burp” but I can’t help but think that! He backs up his assertion by capturing ejected air in a beaker.

              http://www.sciencetoymaker.org/boat/images/bindon9_04.PDF

               

              The engines of my design do not keep running forever.

              http://www.sciencetoymaker.org/boat/index.htm

              My guess is that the straws are too large, both diameter and length, for the pulse to eject the bubble. Perhaps the slant of the straws (horizontal, up, down) might affect it too.

               

              From: pop-pop-steamboats@yahoogroups.com [mailto:pop-pop-steamboats@yahoogroups.com] On Behalf Of Jussi Virtala
              Sent: Wednesday, March 30, 2011 3:40 AM
              To: pop-pop-steamboats@yahoogroups.com
              Subject: [pop-pop-steamboats] Why does the boiler fill with air after a while?

               

               

              Hi Ted

               

              You asked, "How am I getting a run dry state?"

               

              Water has always some air dissolved in it. This is the air fish breath. =)  But when you heat water, the dissolved air evaporates. This evaporated air fills your boiler after a few minutes and your engine stops popping.

               

              When you let your boiler cool the trapped air contracts and pulls some water in to the boiler. So it seems it has some water in the boiler when it's cool, but actually it's empty when it's hot.

               

              Jussi Virtala

               


              From: theo570 <theo570@...>
              To: pop-pop-steamboats@yahoogroups.com
              Sent: Tue, March 29, 2011 7:35:39 PM
              Subject: [pop-pop-steamboats] Re: My Pop Pop is not so lively.....

               

              Test #2 perfomed MUCH better.
              I used the wifes cake dish, leaving the pot sitting over the edge outside. This kept the elevation between pipe openings and pot at less than 2 inches. Lit the candle and in less than a minute it started to bubble a bit. After that a shot of easter egg dye showed one tube sucking and the other pushing. Pretty solid push I might add.

              Still no 'POP' and as William pointed out my brass is just to thick.

              Next problem: It only runs for about 7 minutes and then quits making thrust?? When I remove it from the water it feels like the pot is only about 1/4 full of water?? How am I getting a run dry state?

              Thanks William.

              Ted

              --- In pop-pop-steamboats@yahoogroups.com, William Abernathy <william@...> wrote:
              >
              > I suggest:
              >
              > Bigger fire.
              >
              > Thinner brass.
              >
              > I got similar performance out of mine (thin stream of anemic bubbles) until I
              > added more candles.
              >
              > Jean-Yves's plans suggest that 0.05 mm (0.002") works well and that 0.15 mm
              > (0.006") is too thick. I've used 0.003" brass sheet and it worked great.
              >
              > --William
              >
              > theo570 wrote:
              > > Hey guys, I built my first pop pop engine (actully pot pop, later) and
              > > although she make a bit of steam there is nowhere near enough to push a boat
              > > through the water.
              > >
              > > Ater about 1 min 45 sec I get a steady stream of bubbles. This goes on for
              > > about 1 minute tops. I would guesstimate a bubble a second.
              > >
              > > Because it stops after a minute I think it is not drawing water... it is
              > > probably 3 vertical inches from pipe ends in sink to bottom of boiler...
              > > Pipes are still 10' or so long by the way (not fitted in a boat yet). Any
              > > ideas from the pros??
              > >
              > > Anyhow, the Pot Pop is made of .020 sheet copper that has been peened into a
              > > 1/2 inch nut. This leave me a nice bowl shape which I soldered a peice of
              > > .010 brass to. I added .125 copper pipes about 2/3 way down the bowl. Poics
              > > tomorrow.
              > >
              > > Thanks
              > >
              > > Ted
              >
              >
              > --
              > William Abernathy
              > Berkeley, CA
              > http://yourwritereditor.com
              >



              This message, together with any attachments, may contain information which is privileged and confidential. If the reader of this message is not the intended recipient or the agent responsible for delivering it to the intended recipient, you are hereby notified that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete the message, along with any attachments.


            • Millington, Gavin
              Hi all, First I ve been a lurker here for a while. Thanks. Air in the engine. I ve not built any true Pop-pop engines but have a few coil type engines. I ve
              Message 6 of 12 , Mar 30, 2011
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                Hi all,
                First I've been a lurker here for a while. Thanks.
                 
                Air in the engine.
                I've not built any true Pop-pop engines but have a few coil type engines. I've found that after running for a few minutes, pulsing happily, they cough and jump forwards, before returning to normal pulsing. I had thought this was the coil getting really hot and causing the water to properly flash boil causing the burst into life, before the extra movement caused the flame to be blown from the coil allowing the to cool before the slows and the process starts again.
                 
                After reading this thread, I'm now wondering if the occasional burst into life is the coil clearing the air. Could an air bubble that is slowly building in the coil, stop the cooling of this part of the coil, so the flame can heat part of the coil to a high temperature which then gets hit by the pulsing water causing flash boiling. This flash boiling pushes the air out with the steam.
                 
                Any thoughts?
                Gavin.
                Builder of 3 coil boats made from sardine tins and brake pipe.


                From: pop-pop-steamboats@yahoogroups.com [mailto:pop-pop-steamboats@yahoogroups.com] On Behalf Of Slater Harrison
                Sent: 30 March 2011 13:09
                To: 'pop-pop-steamboats@yahoogroups.com'
                Cc: 'Jeff Bindon'
                Subject: RE: [pop-pop-steamboats] Why does the boiler fill with air after a while?

                 

                Hi All,

                To add to what Jussi has said, there is a good article by Jeff Bindon about pop pops engines in general, and specifically the dissolved air problem. On page 2, column 1 and 2 Jeff contends that a successful engine (one that keeps running) will periodically eject extra air. He didn’t use the word “burp” but I can’t help but think that! He backs up his assertion by capturing ejected air in a beaker.

                http://www.sciencetoymaker.org/boat/images/bindon9_04.PDF

                The engines of my design do not keep running forever.

                http://www.sciencetoymaker.org/boat/index.htm

                My guess is that the straws are too large, both diameter and length, for the pulse to eject the bubble. Perhaps the slant of the straws (horizontal, up, down) might affect it too.

                From: pop-pop-steamboats@yahoogroups.com [mailto:pop-pop-steamboats@yahoogroups.com] On Behalf Of Jussi Virtala
                Sent: Wednesday, March 30, 2011 3:40 AM
                To: pop-pop-steamboats@yahoogroups.com
                Subject: [pop-pop-steamboats] Why does the boiler fill with air after a while?

                 

                Hi Ted

                You asked, "How am I getting a run dry state?"

                Water has always some air dissolved in it. This is the air fish breath. =)  But when you heat water, the dissolved air evaporates. This evaporated air fills your boiler after a few minutes and your engine stops popping.

                When you let your boiler cool the trapped air contracts and pulls some water in to the boiler. So it seems it has some water in the boiler when it's cool, but actually it's empty when it's hot.

                Jussi Virtala


                From: theo570 <theo570@...>
                To: pop-pop-steamboats@yahoogroups.com
                Sent: Tue, March 29, 2011 7:35:39 PM
                Subject: [pop-pop-steamboats] Re: My Pop Pop is not so lively.....

                 

                Test #2 perfomed MUCH better.
                I used the wifes cake dish, leaving the pot sitting over the edge outside. This kept the elevation between pipe openings and pot at less than 2 inches. Lit the candle and in less than a minute it started to bubble a bit. After that a shot of easter egg dye showed one tube sucking and the other pushing. Pretty solid push I might add.

                Still no 'POP' and as William pointed out my brass is just to thick.

                Next problem: It only runs for about 7 minutes and then quits making thrust?? When I remove it from the water it feels like the pot is only about 1/4 full of water?? How am I getting a run dry state?

                Thanks William.

                Ted

                --- In pop-pop-steamboats@yahoogroups.com, William Abernathy <william@...> wrote:

                >
                > I suggest:
                >
                > Bigger
                fire.
                >
                > Thinner brass.
                >
                > I got similar performance
                out of mine (thin stream of anemic bubbles) until I
                > added more
                candles.
                >
                > Jean-Yves's plans suggest that 0.05 mm (0.002") works
                well and that 0.15 mm
                > (0.006") is too thick. I've used 0.003" brass
                sheet and it worked great.
                >
                > --William
                >
                > theo570
                wrote:
                > > Hey guys, I built my first pop pop engine (actully pot pop,
                later) and
                > > although she make a bit of steam there is nowhere near
                enough to push a boat
                > > through the water.
                > >
                > >
                Ater about 1 min 45 sec I get a steady stream of bubbles. This goes on for
                > > about 1 minute tops. I would guesstimate a bubble a
                second.
                > >
                > > Because it stops after a minute I think it is
                not drawing water... it is
                > > probably 3 vertical inches from pipe
                ends in sink to bottom of boiler...
                > > Pipes are still 10' or so long
                by the way (not fitted in a boat yet). Any
                > > ideas from the
                pros??
                > >
                > > Anyhow, the Pot Pop is made of .020 sheet
                copper that has been peened into a
                > > 1/2 inch nut. This leave me a
                nice bowl shape which I soldered a peice of
                > > .010 brass to. I added
                .125 copper pipes about 2/3 way down the bowl. Poics
                > >
                tomorrow.
                > >
                > > Thanks
                > >
                > > Ted
                >
                >
                > --
                > William Abernathy
                > Berkeley, CA
                >
                http://yourwritereditor.com
                >



                This message, together with any attachments, may contain information which is privileged and confidential. If the reader of this message is not the intended recipient or the agent responsible for delivering it to the intended recipient, you are hereby notified that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete the message, along with any attachments.



                This message (and any attachment) is confidential and is intended for the named recipient only.
                If you receive it in error please e-mail back the sender and permanently delete the original message and any copies.
                Rolls-Royce Goodrich Engine Control Systems Limited.
                Registered Office: Moor Lane, PO Box 31, Derby, DE24 8BJ.
                Registered in England No. 06686268.



                This message (and any attachment) is confidential and is intended for the named recipient only.
                If you receive it in error please e-mail back the sender and permanently delete the original message and any copies.
                Rolls-Royce Goodrich Engine Control Systems Limited.

                Registered Office: Moor Lane, PO Box 31, Derby, DE24 8BJ.

                Registered in England No. 06686268.


              • jeanyves_renaud
                Hi Jussi, Ted and Slater. Let me add some explanations. (More details are available on Loïc s site www.eclecticspace.net .) Though it is not exactly air that
                Message 7 of 12 , Mar 30, 2011
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                  Hi Jussi, Ted and Slater.
                  Let me add some explanations. (More details are available on Loïc's site www.eclecticspace.net .)
                  Though it is not exactly air that is dissolved in water, it is mostly nitrogen and oxygen and the proportions are close to their ones in air. At a given pressure, every gas is more or less dissolved depending on the water temperature. This is known as Henry's law.
                  When the water is heated a certain amount of the dissolved gasses evaporates. In the particular case of pop-pop engines, due to the reciprocating movement of the water, at every cycle some water is expelled and replaced by the same amount of cooler water. This lead to more and more gas trapped versus time at the upper part of the engine which is generally the boiler. But this gas production is a slow process. It can be calculated and I measured it.
                  If you start with an engine full of water you will notice after a while that the performance (frequency, thrust) is better. And better... After a rather long time (commonly something as 45 minutes) the engine gives its best. You could save this « choking » time by putting some air inside the engine before lighting the burner. Look at Slater's procedure.
                  Then, if the engine is well designed it could run for hours, expelling bubbles with water. If this is not the case, when there is too much gas the engine stops popping and this is a classic burnout.
                  As said, "when you let your boiler cool the trapped air contracts and pulls some water in to the boiler". In normal conditions, the gas contracts only because it goes from approx 100°C (212°F) to 20°C (68°F) viz 373K to 293K. Therefore, its volume decreases only by approx 22%. It can easily be checked with transparent engines made of glass. But if the engine was highly overheated when you stopped the fire the contraction could be more. And sometimes when the water approaches the boiler (cooling but still hot) the engine restarts for a few seconds until the boiler temp is lower than 100°C.
                  Jean-Yves

                  --- In pop-pop-steamboats@yahoogroups.com, Slater Harrison <Sharrison@...> wrote:
                  >
                  > Hi All,
                  >
                  > To add to what Jussi has said, there is a good article by Jeff Bindon about pop pops engines in general, and specifically the dissolved air problem. On page 2, column 1 and 2 Jeff contends that a successful engine (one that keeps running) will periodically eject extra air. He didn’t use the word “burp” but I can’t help but think that! He backs up his assertion by capturing ejected air in a beaker.
                  > http://www.sciencetoymaker.org/boat/images/bindon9_04.PDF
                  >
                  > The engines of my design do not keep running forever.
                  > http://www.sciencetoymaker.org/boat/index.htm
                  > My guess is that the straws are too large, both diameter and length, for the pulse to eject the bubble. Perhaps the slant of the straws (horizontal, up, down) might affect it too.
                  >
                  > From: pop-pop-steamboats@yahoogroups.com [mailto:pop-pop-steamboats@yahoogroups.com] On Behalf Of Jussi Virtala
                  > Sent: Wednesday, March 30, 2011 3:40 AM
                  > To: pop-pop-steamboats@yahoogroups.com
                  > Subject: [pop-pop-steamboats] Why does the boiler fill with air after a while?
                  >
                  >
                  > Hi Ted
                  >
                  > You asked, "How am I getting a run dry state?"
                  >
                  > Water has always some air dissolved in it. This is the air fish breath. =) But when you heat water, the dissolved air evaporates. This evaporated air fills your boiler after a few minutes and your engine stops popping.
                  >
                  > When you let your boiler cool the trapped air contracts and pulls some water in to the boiler. So it seems it has some water in the boiler when it's cool, but actually it's empty when it's hot.
                  >
                  > Jussi Virtala
                  >
                  > ________________________________
                  > From: theo570 <theo570@...>
                  > To: pop-pop-steamboats@yahoogroups.com
                  > Sent: Tue, March 29, 2011 7:35:39 PM
                  > Subject: [pop-pop-steamboats] Re: My Pop Pop is not so lively.....
                  >
                  >
                  >
                  > Test #2 perfomed MUCH better.
                  > I used the wifes cake dish, leaving the pot sitting over the edge outside. This kept the elevation between pipe openings and pot at less than 2 inches. Lit the candle and in less than a minute it started to bubble a bit. After that a shot of easter egg dye showed one tube sucking and the other pushing. Pretty solid push I might add.
                  >
                  > Still no 'POP' and as William pointed out my brass is just to thick.
                  >
                  > Next problem: It only runs for about 7 minutes and then quits making thrust?? When I remove it from the water it feels like the pot is only about 1/4 full of water?? How am I getting a run dry state?
                  >
                  > Thanks William.
                  >
                  > Ted
                  >
                  > --- In pop-pop-steamboats@yahoogroups.com<mailto:pop-pop-steamboats%40yahoogroups.com>, William Abernathy <william@> wrote:
                  > >
                  > > I suggest:
                  > >
                  > > Bigger fire.
                  > >
                  > > Thinner brass.
                  > >
                  > > I got similar performance out of mine (thin stream of anemic bubbles) until I
                  > > added more candles.
                  > >
                  > > Jean-Yves's plans suggest that 0.05 mm (0.002") works well and that 0.15 mm
                  > > (0.006") is too thick. I've used 0.003" brass sheet and it worked great.
                  > >
                  > > --William
                  > >
                  > > theo570 wrote:
                  > > > Hey guys, I built my first pop pop engine (actully pot pop, later) and
                  > > > although she make a bit of steam there is nowhere near enough to push a boat
                  > > > through the water.
                  > > >
                  > > > Ater about 1 min 45 sec I get a steady stream of bubbles. This goes on for
                  > > > about 1 minute tops. I would guesstimate a bubble a second.
                  > > >
                  > > > Because it stops after a minute I think it is not drawing water... it is
                  > > > probably 3 vertical inches from pipe ends in sink to bottom of boiler...
                  > > > Pipes are still 10' or so long by the way (not fitted in a boat yet). Any
                  > > > ideas from the pros??
                  > > >
                  > > > Anyhow, the Pot Pop is made of .020 sheet copper that has been peened into a
                  > > > 1/2 inch nut. This leave me a nice bowl shape which I soldered a peice of
                  > > > .010 brass to. I added .125 copper pipes about 2/3 way down the bowl. Poics
                  > > > tomorrow.
                  > > >
                  > > > Thanks
                  > > >
                  > > > Ted
                  > >
                  > >
                  > > --
                  > > William Abernathy
                  > > Berkeley, CA
                  > > http://yourwritereditor.com
                  > >
                  >
                  >
                  > ________________________________
                  > This message, together with any attachments, may contain information which is privileged and confidential. If the reader of this message is not the intended recipient or the agent responsible for delivering it to the intended recipient, you are hereby notified that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete the message, along with any attachments.
                  >
                • jeanyves_renaud
                  Hi Gavin. Depending how they are heated, coil engines could have several natural frequencies because each loop can contain water and gas, and not the same
                  Message 8 of 12 , Mar 30, 2011
                  • 0 Attachment
                    Hi Gavin.
                    Depending how they are heated, coil engines could have several natural frequencies because each loop can contain water and gas, and not the same amount. And there are transfers from one loop to the adjacent ones. Not easy to tell you with certainty what happens on your engine.
                    However, such a running exists with any type of pop-pop engine (coil, drum, diaphragm) and is generally due to too much heat from the burner. Several of us tried to operate engines on the "cough and jump forward" mode. Alas... As far as I know, nobody succeeded.
                    Note that when analyzing the performances of an engine, it can be observed that before or/and after a "cough and jump forward" there is a relative calm mode and the average is not better than when "pulsating happily".
                    Jean-Yves

                    --- In pop-pop-steamboats@yahoogroups.com, "Millington, Gavin" <gavin.millington@...> wrote:
                    >
                    > Hi all,
                    > First I've been a lurker here for a while. Thanks.
                    >
                    > Air in the engine.
                    > I've not built any true Pop-pop engines but have a few coil type
                    > engines. I've found that after running for a few minutes, pulsing
                    > happily, they cough and jump forwards, before returning to normal
                    > pulsing. I had thought this was the coil getting really hot and causing
                    > the water to properly flash boil causing the burst into life, before the
                    > extra movement caused the flame to be blown from the coil allowing the
                    > to cool before the slows and the process starts again.
                    >
                    > After reading this thread, I'm now wondering if the occasional burst
                    > into life is the coil clearing the air. Could an air bubble that is
                    > slowly building in the coil, stop the cooling of this part of the coil,
                    > so the flame can heat part of the coil to a high temperature which then
                    > gets hit by the pulsing water causing flash boiling. This flash boiling
                    > pushes the air out with the steam.
                    >
                    > Any thoughts?
                    > Gavin.
                    > Builder of 3 coil boats made from sardine tins and brake pipe.
                    >
                    > ________________________________
                    >
                    > From: pop-pop-steamboats@yahoogroups.com
                    > [mailto:pop-pop-steamboats@yahoogroups.com] On Behalf Of Slater Harrison
                    > Sent: 30 March 2011 13:09
                    > To: 'pop-pop-steamboats@yahoogroups.com'
                    > Cc: 'Jeff Bindon'
                    > Subject: RE: [pop-pop-steamboats] Why does the boiler fill with air
                    > after a while?
                    >
                    >
                    >
                    >
                    > Hi All,
                    >
                    > To add to what Jussi has said, there is a good article by Jeff Bindon
                    > about pop pops engines in general, and specifically the dissolved air
                    > problem. On page 2, column 1 and 2 Jeff contends that a successful
                    > engine (one that keeps running) will periodically eject extra air. He
                    > didn't use the word "burp" but I can't help but think that! He backs up
                    > his assertion by capturing ejected air in a beaker.
                    >
                    > http://www.sciencetoymaker.org/boat/images/bindon9_04.PDF
                    >
                    > The engines of my design do not keep running forever.
                    >
                    > http://www.sciencetoymaker.org/boat/index.htm
                    >
                    > My guess is that the straws are too large, both diameter and length, for
                    > the pulse to eject the bubble. Perhaps the slant of the straws
                    > (horizontal, up, down) might affect it too.
                    >
                    > From: pop-pop-steamboats@yahoogroups.com
                    > [mailto:pop-pop-steamboats@yahoogroups.com] On Behalf Of Jussi Virtala
                    > Sent: Wednesday, March 30, 2011 3:40 AM
                    > To: pop-pop-steamboats@yahoogroups.com
                    > Subject: [pop-pop-steamboats] Why does the boiler fill with air after a
                    > while?
                    >
                    >
                    >
                    > Hi Ted
                    >
                    > You asked, "How am I getting a run dry state?"
                    >
                    > Water has always some air dissolved in it. This is the air fish breath.
                    > =) But when you heat water, the dissolved air evaporates. This
                    > evaporated air fills your boiler after a few minutes and your engine
                    > stops popping.
                    >
                    > When you let your boiler cool the trapped air contracts and pulls some
                    > water in to the boiler. So it seems it has some water in the boiler when
                    > it's cool, but actually it's empty when it's hot.
                    >
                    > Jussi Virtala
                    >
                    > ________________________________
                    >
                    > From: theo570 <theo570@...>
                    > To: pop-pop-steamboats@yahoogroups.com
                    > Sent: Tue, March 29, 2011 7:35:39 PM
                    > Subject: [pop-pop-steamboats] Re: My Pop Pop is not so lively.....
                    >
                    >
                    >
                    > Test #2 perfomed MUCH better.
                    > I used the wifes cake dish, leaving the pot sitting over the edge
                    > outside. This kept the elevation between pipe openings and pot at less
                    > than 2 inches. Lit the candle and in less than a minute it started to
                    > bubble a bit. After that a shot of easter egg dye showed one tube
                    > sucking and the other pushing. Pretty solid push I might add.
                    >
                    > Still no 'POP' and as William pointed out my brass is just to thick.
                    >
                    > Next problem: It only runs for about 7 minutes and then quits making
                    > thrust?? When I remove it from the water it feels like the pot is only
                    > about 1/4 full of water?? How am I getting a run dry state?
                    >
                    > Thanks William.
                    >
                    > Ted
                    >
                    > --- In pop-pop-steamboats@yahoogroups.com
                    > <mailto:pop-pop-steamboats%40yahoogroups.com> , William Abernathy
                    > <william@> wrote:
                    > >
                    > > I suggest:
                    > >
                    > > Bigger fire.
                    > >
                    > > Thinner brass.
                    > >
                    > > I got similar performance out of mine (thin stream of anemic bubbles)
                    > until I
                    > > added more candles.
                    > >
                    > > Jean-Yves's plans suggest that 0.05 mm (0.002") works well and that
                    > 0.15 mm
                    > > (0.006") is too thick. I've used 0.003" brass sheet and it worked
                    > great.
                    > >
                    > > --William
                    > >
                    > > theo570 wrote:
                    > > > Hey guys, I built my first pop pop engine (actully pot pop, later)
                    > and
                    > > > although she make a bit of steam there is nowhere near enough to
                    > push a boat
                    > > > through the water.
                    > > >
                    > > > Ater about 1 min 45 sec I get a steady stream of bubbles. This goes
                    > on for
                    > > > about 1 minute tops. I would guesstimate a bubble a second.
                    > > >
                    > > > Because it stops after a minute I think it is not drawing water...
                    > it is
                    > > > probably 3 vertical inches from pipe ends in sink to bottom of
                    > boiler...
                    > > > Pipes are still 10' or so long by the way (not fitted in a boat
                    > yet). Any
                    > > > ideas from the pros??
                    > > >
                    > > > Anyhow, the Pot Pop is made of .020 sheet copper that has been
                    > peened into a
                    > > > 1/2 inch nut. This leave me a nice bowl shape which I soldered a
                    > peice of
                    > > > .010 brass to. I added .125 copper pipes about 2/3 way down the
                    > bowl. Poics
                    > > > tomorrow.
                    > > >
                    > > > Thanks
                    > > >
                    > > > Ted
                    > >
                    > >
                    > > --
                    > > William Abernathy
                    > > Berkeley, CA
                    > > http://yourwritereditor.com
                    > >
                    >
                    >
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                  • theo570
                    Ok, in my design I have what amounts to a large boiler in that it is 1.5 inches in diameter and about .75 inches deep (Dome). I have both pipes (.125 OD, about
                    Message 9 of 12 , Mar 31, 2011
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                      Ok, in my design I have what amounts to a large boiler in that it is 1.5 inches in diameter and about .75 inches deep (Dome). I have both pipes (.125 OD, about .100 ID) terminating in the center bottomish area of the dome.

                      My two conclusions in my lack of 'spirit' from the motor are:

                      A - Way to much volume in the boiler.
                      B - Pipe location.

                      I think the volume of the boiler needs to more closely match the volume over time of the generated steam.

                      I also think that staggering the pipes inside the boiler will have a greater effect in 'burping' an unwanted gas pocket.

                      Off the the workbench for some soldering.

                      Ted
                    • zoomkat
                      Lot of different ideas on how pop pop engines work and what would be the best design. I think the bottom line principal idea is that the boiler internal volume
                      Message 10 of 12 , Mar 31, 2011
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                        Lot of different ideas on how pop pop engines work and what would be the best design. I think the bottom line principal idea is that the boiler internal volume needs to be small with a fairly large heated surface area. The steam needs to be generated in a "flash" (flash boiler) to generate high pressure steam to eject the water from the exhaust pipes very rapidly. Anything less and the engine just turns into a still.


                        --- In pop-pop-steamboats@yahoogroups.com, "theo570" <theo570@...> wrote:
                        >
                        >
                        > Ok, in my design I have what amounts to a large boiler in that it is 1.5 inches in diameter and about .75 inches deep (Dome). I have both pipes (.125 OD, about .100 ID) terminating in the center bottomish area of the dome.
                        >
                        > My two conclusions in my lack of 'spirit' from the motor are:
                        >
                        > A - Way to much volume in the boiler.
                        > B - Pipe location.
                        >
                        > I think the volume of the boiler needs to more closely match the volume over time of the generated steam.
                        >
                        > I also think that staggering the pipes inside the boiler will have a greater effect in 'burping' an unwanted gas pocket.
                        >
                        > Off the the workbench for some soldering.
                        >
                        > Ted
                        >
                      • Daryl
                        From your description if I understand correctly I would suggest a maximum depth of the boiler at about 1/8 inch and the rise from the top of the pipe outlets
                        Message 11 of 12 , Apr 1, 2011
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                          From your description if I understand correctly I would suggest a maximum depth of the boiler at about 1/8 inch and the rise from the top of the pipe outlets to the top of the boiler at about 3/4 inch. Location of the pipes entering the boiler do not seem to have much effect either way but for a low heat diaphragm engine I would place them at the low point of the boiler. Zoomcat is quite right about small volume though this does make an engine more fussy about getting the amount of heat correct. If you reduce the volume start with very low heat and add if necessary as you test. Good luck Ted.

                          --- In pop-pop-steamboats@yahoogroups.com, "theo570" <theo570@...> wrote:
                          >
                          >
                          > Ok, in my design I have what amounts to a large boiler in that it is 1.5 inches in diameter and about .75 inches deep (Dome). I have both pipes (.125 OD, about .100 ID) terminating in the center bottomish area of the dome.
                          >
                          > My two conclusions in my lack of 'spirit' from the motor are:
                          >
                          > A - Way to much volume in the boiler.
                          > B - Pipe location.
                          >
                          > I think the volume of the boiler needs to more closely match the volume over time of the generated steam.
                          >
                          > I also think that staggering the pipes inside the boiler will have a greater effect in 'burping' an unwanted gas pocket.
                          >
                          > Off the the workbench for some soldering.
                          >
                          > Ted
                          >
                        • Daryl
                          PS Read your pipe size as .125 ID then realized it was OD. This is a bit small. Perhaps 1/8 t0 5/32 ID would be better. D.
                          Message 12 of 12 , Apr 2, 2011
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                            PS Read your pipe size as .125 ID then realized it was OD. This is a bit small. Perhaps 1/8 t0 5/32 ID would be better. D.

                            --- In pop-pop-steamboats@yahoogroups.com, "theo570" <theo570@...> wrote:
                            >
                            >
                            > Ok, in my design I have what amounts to a large boiler in that it is 1.5 inches in diameter and about .75 inches deep (Dome). I have both pipes (.125 OD, about .100 ID) terminating in the center bottomish area of the dome.
                            >
                            > My two conclusions in my lack of 'spirit' from the motor are:
                            >
                            > A - Way to much volume in the boiler.
                            > B - Pipe location.
                            >
                            > I think the volume of the boiler needs to more closely match the volume over time of the generated steam.
                            >
                            > I also think that staggering the pipes inside the boiler will have a greater effect in 'burping' an unwanted gas pocket.
                            >
                            > Off the the workbench for some soldering.
                            >
                            > Ted
                            >
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