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Re: Peter R Payne and proper boats.

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  • Richard Mundy
    Hi David, thanks for putting this into perspective, this is entirely for fun and is a subject that can be tinkered with indefinately, but as Jean- Yves points
    Message 1 of 29 , Jan 21, 2009
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      Hi David,
      thanks for putting this into perspective, this is entirely for fun
      and is a subject that can be tinkered with indefinately, but as Jean-
      Yves points out, the likelyhood of a high powered big pop pop is very
      slim.
      Time to start torturing metal!!

      Dick

      --- In pop-pop-steamboats@yahoogroups.com, "David Halfpenny"
      <dh1@...> wrote:
      >
      > --------------------------------------------------
      > From: "Richard Mundy" <coracles18@...>
      > Sent: Tuesday, January 20, 2009 10:02 PM
      > To: <pop-pop-steamboats@yahoogroups.com>
      > Subject: [pop-pop-steamboats] Re: Peter R Payne and proper boats.
      >
      > > Hi David,
      > > I think the condensing is done in the tube, which creates another
      > > problem. Condensing steam in a tiny tube is a lot quicker than
      doing
      > > it in a big tube.
      > > An interesting aspect of Paynes original patent is using the
      momentum
      > > of the returning water to compress the remaining steam in the
      boiler.
      > > This should raise the boiling point so the steam has more kick to
      it.
      > > If this effect is significant I have no idea.
      > > More important I suspect is to have a forward facing intake and
      > > valves.
      > > Also, what about an output nozzle? you can significantly increase
      the
      > > velocity of water coming out of a hosepipe by sticking your finger
      > > over the end.
      > > This would also increase the pressure in the boiler and give the
      > > whole thing more go?
      > >
      >
      > This is basically a bit of fun in the bathtub. But if Payne missed
      > something big, as well he might, then we aren't going to find it in
      this
      > kind of conversation, entertaining as it is.
      >
      > We are talking about a resonant system involving an air spring of
      unknown
      > size, ever-reversing heat flow, the properties of steam and water
      under
      > rapidly varying pressure, and the movement of a heavy craft at low
      speed
      > under tiny fluctuating loads. There is virtually no experimental
      data, and
      > few if any of our members have either the maths, the mechanics or
      the
      > thermodynamics to discuss any part of it at a theoretical level.
      Despite
      > the simplicity of the device, it is vastly more complicated than,
      say, an
      > ordinary three cylinder compound marine steam engine. It has been
      usefully
      > demonstrated by Payne that when scaled up in a simple manner the
      power
      > required became enormous yet the result remained pathetic.
      >
      > What would be needed to improve on that would be a set of
      experiments in
      > which every part of the apparatus had rapid-acting pressure and
      temperature
      > sensors, backed up an ever more sophisticated non-linear
      computer "model"
      > based on real thermodynamics until the whole process was understood.
      >
      > The exciting thing is that this is actually all within the scope of
      a smart
      > pensioner with modest means.
      >
      > Meanwhile, the complexity is such that the best answer to questions
      about
      > valves and nozzles is still "Try it!" (Please.)
      >
      > David 1/2d
      >
    • David Halfpenny
      ... From: Richard Mundy Sent: Wednesday, January 21, 2009 7:31 PM ... That s the spirit! D
      Message 2 of 29 , Jan 21, 2009
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        --------------------------------------------------
        From: "Richard Mundy" <coracles18@...>
        Sent: Wednesday, January 21, 2009 7:31 PM

        > Time to start torturing metal!!
        >
        That's the spirit! D
      • Jean-Yves Renaud
        Dick, your biscuit tin/blow lamp boat moved back and forth (more or less as every pop-pop boat) not because of the suction, but because of the inertia of the
        Message 3 of 29 , Jan 22, 2009
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          Dick, your biscuit tin/blow lamp boat moved back and forth (more or
          less as every pop-pop boat) not because of the suction, but because
          of the inertia of the water contained inside the pipes.
          It very easy to demonstrate that the suction is not the cause. On a
          classic pop-pop boat with two pipes, just bend one on port and the
          other one on starboard. Thus, there will be no more thrust (port and
          starboard being equal and opposite). The boat will no longer progress
          forward, but it will go on vibrating back and forth as before.
          If you have a single pipe engine, just bend the outlet vertically
          downward and the result will be the same.
          Jean-Yves



          --- In pop-pop-steamboats@yahoogroups.com, "Richard Mundy"
          <coracles18@...> wrote:
          >
          > Hi Jean-Yves,
          > you keep knocking down my skittles:-).
          > Seriously, I value your input hugely. Apart from a few experiments
          > perhaps 10 years ago, I am coming at this subject from a 'what if'
          > angle. I remember my biscuit tin/blow lamp boat moved forwards then
          a
          > little back per cycle. So there is a slight reverse pull on the
          > intake. I suspect tho that that the valves unless very carefully
          > designed would further reduce efficiency and as you suggest make
          the
          > forward facing inlet pointless.
          >
          > On the subject of nozzles, I have no experience, I just wondered if
          > it had been tried.
          >
          > Conventional boilers work at high pressure so the steam can hold
          more
          > energy. In a pop pop the boiler is, via the water, open to the
          > atmosphere. effectively like a kettle, and the steam produced is
          very
          > rapidly condensed by contact with the water and the unlagged exit
          > tube. All this accounts for at least some of the inefficiency of
          the
          > pop pop, hence throttling the output to up the pressure and speed
          up
          > the output flow. But will it still work? If it actually reduces
          > efficiency, why?
          >
          > Dick
          >
          >
          > --- In pop-pop-steamboats@yahoogroups.com, "Jean-Yves Renaud"
          > <boite.de.j-y@> wrote:
          > >
          > > Hi Dick,
          > > I would like to comment 2 topics of your last post: facing intake
          > and
          > > nozzle.
          > > 1°) Facing intake.
          > > Everybody thinks at the beginning that using a facing intake (and
          > > valves) could improve the performance of pop-pop propulsion. Even
          > > Peter Payne thought that. But facing intake is useless, or more
          > > exactly so inefficient that it becomes useless.
          > > • By math demo it can be proven that the effect of such a
          > > modification is negligible.
          > > • For those who dislike math, there is an easy way to check
          > > that sucking is far less efficient than blowing. Try to blow a
          > candle
          > > by sucking air!
          > > • In addition, to prove this inefficiency, 2 years ago I built
          > > a small boat with an electric pump to show that sucking water on
          > the
          > > bow has a negligible impact; though a jet backward propels. The
          > > pulling force (when sucking) was roughly 20 millions times weaker
          > > than the pushing one.
          > > 2°) Nozzle.
          > > The thrust of a waterjet evolving with the square of the velocity
          > of
          > > the water that is expelled it seems evident that a nozzle could
          > > improve the performance. However, on a pop-pop engine a nozzle
          acts
          > > also on the frequency, stroke volume…and this is detrimental. We
          > > don't know enough to give precise figures, but it seems that the
          > best
          > > nozzle has a diameter reduced by only 5 to 10%. On this forum
          Daryl
          > > is very likely the one who has got the best practical knowledge
          on
          > > this topic. Most of his engines are provided with nozzles and his
          > > engines are among the best ones if not the best.
          > > Jean-Yves
          > >
          > >
          > > --- In pop-pop-steamboats@yahoogroups.com, "Richard Mundy"
          > > <coracles18@> wrote:
          > > >
          > > > Hi David,
          > > > I think the condensing is done in the tube, which creates
          another
          > > > problem. Condensing steam in a tiny tube is a lot quicker than
          > > doing
          > > > it in a big tube.
          > > > An interesting aspect of Paynes original patent is using the
          > > momentum
          > > > of the returning water to compress the remaining steam in the
          > > boiler.
          > > > This should raise the boiling point so the steam has more kick
          to
          > > it.
          > > > If this effect is significant I have no idea.
          > > > More important I suspect is to have a forward facing intake and
          > > > valves.
          > > > Also, what about an output nozzle? you can significantly
          increase
          > > the
          > > > velocity of water coming out of a hosepipe by sticking your
          > finger
          > > > over the end.
          > > > This would also increase the pressure in the boiler and give
          the
          > > > whole thing more go?
          > > >
          > > > Dick
          > > >
          > > >
          > > >
          > > > --- In pop-pop-steamboats@yahoogroups.com, "David Halfpenny"
          > > > <dh1@> wrote:
          > > > >
          > > > >
          > > > >
          > > > > --------------------------------------------------
          > > > > From: "Richard Mundy" <coracles18@>
          > > > > Sent: Tuesday, January 20, 2009 7:44 PM
          > > > >
          > > > > > As the engines grow bigger there is a need to create a lot
          of
          > > > steam a
          > > > > > lot faster.
          > > > >
          > > > > AND then condense a tube-full of it in a similar time, in the
          > > very
          > > > boiler
          > > > > you have just heated it in!
          > > > >
          > > > > That is exactly the snag that Newcomen had - though with much
          > > less
          > > > thermal
          > > > > capacity to heat and cool each pulse.
          > > > >
          > > > > David 1/2d
          > > > >
          > > >
          > >
          >
        • Richard Mundy
          Hi Jean-Yves, Yet another thing to think about. I had thought about momentum of the water column, but not its inertia. Dick ... and ... progress ...
          Message 4 of 29 , Jan 23, 2009
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            Hi Jean-Yves,

            Yet another thing to think about. I had thought about momentum of the
            water column, but not its inertia.

            Dick



            --- In pop-pop-steamboats@yahoogroups.com, "Jean-Yves Renaud"
            <boite.de.j-y@...> wrote:
            >
            > Dick, your biscuit tin/blow lamp boat moved back and forth (more or
            > less as every pop-pop boat) not because of the suction, but because
            > of the inertia of the water contained inside the pipes.
            > It very easy to demonstrate that the suction is not the cause. On a
            > classic pop-pop boat with two pipes, just bend one on port and the
            > other one on starboard. Thus, there will be no more thrust (port
            and
            > starboard being equal and opposite). The boat will no longer
            progress
            > forward, but it will go on vibrating back and forth as before.
            > If you have a single pipe engine, just bend the outlet vertically
            > downward and the result will be the same.
            > Jean-Yves
            >
            >
            >
            > --- In pop-pop-steamboats@yahoogroups.com, "Richard Mundy"
            > <coracles18@> wrote:
            > >
            > > Hi Jean-Yves,
            > > you keep knocking down my skittles:-).
            > > Seriously, I value your input hugely. Apart from a few
            experiments
            > > perhaps 10 years ago, I am coming at this subject from a 'what
            if'
            > > angle. I remember my biscuit tin/blow lamp boat moved forwards
            then
            > a
            > > little back per cycle. So there is a slight reverse pull on the
            > > intake. I suspect tho that that the valves unless very carefully
            > > designed would further reduce efficiency and as you suggest make
            > the
            > > forward facing inlet pointless.
            > >
            > > On the subject of nozzles, I have no experience, I just wondered
            if
            > > it had been tried.
            > >
            > > Conventional boilers work at high pressure so the steam can hold
            > more
            > > energy. In a pop pop the boiler is, via the water, open to the
            > > atmosphere. effectively like a kettle, and the steam produced is
            > very
            > > rapidly condensed by contact with the water and the unlagged exit
            > > tube. All this accounts for at least some of the inefficiency of
            > the
            > > pop pop, hence throttling the output to up the pressure and speed
            > up
            > > the output flow. But will it still work? If it actually reduces
            > > efficiency, why?
            > >
            > > Dick
            > >
            > >
            > > --- In pop-pop-steamboats@yahoogroups.com, "Jean-Yves Renaud"
            > > <boite.de.j-y@> wrote:
            > > >
            > > > Hi Dick,
            > > > I would like to comment 2 topics of your last post: facing
            intake
            > > and
            > > > nozzle.
            > > > 1°) Facing intake.
            > > > Everybody thinks at the beginning that using a facing intake
            (and
            > > > valves) could improve the performance of pop-pop propulsion.
            Even
            > > > Peter Payne thought that. But facing intake is useless, or more
            > > > exactly so inefficient that it becomes useless.
            > > > • By math demo it can be proven that the effect of such a
            > > > modification is negligible.
            > > > • For those who dislike math, there is an easy way to check
            > > > that sucking is far less efficient than blowing. Try to blow a
            > > candle
            > > > by sucking air!
            > > > • In addition, to prove this inefficiency, 2 years ago I built
            > > > a small boat with an electric pump to show that sucking water
            on
            > > the
            > > > bow has a negligible impact; though a jet backward propels. The
            > > > pulling force (when sucking) was roughly 20 millions times
            weaker
            > > > than the pushing one.
            > > > 2°) Nozzle.
            > > > The thrust of a waterjet evolving with the square of the
            velocity
            > > of
            > > > the water that is expelled it seems evident that a nozzle could
            > > > improve the performance. However, on a pop-pop engine a nozzle
            > acts
            > > > also on the frequency, stroke volume…and this is detrimental.
            We
            > > > don't know enough to give precise figures, but it seems that
            the
            > > best
            > > > nozzle has a diameter reduced by only 5 to 10%. On this forum
            > Daryl
            > > > is very likely the one who has got the best practical knowledge
            > on
            > > > this topic. Most of his engines are provided with nozzles and
            his
            > > > engines are among the best ones if not the best.
            > > > Jean-Yves
            > > >
            > > >
            > > > --- In pop-pop-steamboats@yahoogroups.com, "Richard Mundy"
            > > > <coracles18@> wrote:
            > > > >
            > > > > Hi David,
            > > > > I think the condensing is done in the tube, which creates
            > another
            > > > > problem. Condensing steam in a tiny tube is a lot quicker
            than
            > > > doing
            > > > > it in a big tube.
            > > > > An interesting aspect of Paynes original patent is using the
            > > > momentum
            > > > > of the returning water to compress the remaining steam in the
            > > > boiler.
            > > > > This should raise the boiling point so the steam has more
            kick
            > to
            > > > it.
            > > > > If this effect is significant I have no idea.
            > > > > More important I suspect is to have a forward facing intake
            and
            > > > > valves.
            > > > > Also, what about an output nozzle? you can significantly
            > increase
            > > > the
            > > > > velocity of water coming out of a hosepipe by sticking your
            > > finger
            > > > > over the end.
            > > > > This would also increase the pressure in the boiler and give
            > the
            > > > > whole thing more go?
            > > > >
            > > > > Dick
            > > > >
            > > > >
            > > > >
            > > > > --- In pop-pop-steamboats@yahoogroups.com, "David Halfpenny"
            > > > > <dh1@> wrote:
            > > > > >
            > > > > >
            > > > > >
            > > > > > --------------------------------------------------
            > > > > > From: "Richard Mundy" <coracles18@>
            > > > > > Sent: Tuesday, January 20, 2009 7:44 PM
            > > > > >
            > > > > > > As the engines grow bigger there is a need to create a
            lot
            > of
            > > > > steam a
            > > > > > > lot faster.
            > > > > >
            > > > > > AND then condense a tube-full of it in a similar time, in
            the
            > > > very
            > > > > boiler
            > > > > > you have just heated it in!
            > > > > >
            > > > > > That is exactly the snag that Newcomen had - though with
            much
            > > > less
            > > > > thermal
            > > > > > capacity to heat and cool each pulse.
            > > > > >
            > > > > > David 1/2d
            > > > > >
            > > > >
            > > >
            > >
            >
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