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Re: [pop-pop-steamboats] Re: Interesting pop pop boat engine experiments.

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  • Daryl Foster
    As always Donald, you make me think and I will think on your comments. I would like to test augmenters, preferably on my 7 tube engines as I have several that
    Message 1 of 10 , Jul 6, 2011
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      As always Donald, you make me think and I will think on your comments. I would like to test augmenters, preferably on my 7 tube engines as I have several that are near identical and are comparatively (for putt putts) excellent performers by all measures. Guess I need a way to mass produce them.
      A couple of questions first though. The velocity of a putt putt engine power stroke is not very high but is improved considerably with the use of nozzles. What is the velocity of a pulse jet engine exhaust? 
       
      Could you clarify your last paragraph:-" I'd bet
      you get between 20% and 80% increase in thrust, measured by the beam or
      draft of the boat (same waterline length) that can be pushed up to hull
      speed"  Reaching hull speed with a putt putt seems unlikely without a very major break through if that is what you are suggesting. .


      --- On Tue, 7/5/11, Donald Qualls <silent1@...> wrote:

      From: Donald Qualls <silent1@...>
      Subject: Re: [pop-pop-steamboats] Re: Interesting pop pop boat engine experiments.
      To: pop-pop-steamboats@yahoogroups.com
      Received: Tuesday, July 5, 2011, 8:39 PM

      I think he's deeply confused concerning the "valve-like" operation of an
      augmenter, but I'd actually expect a correctly proportioned augmenter to
      increase the thrust of a pop-pop.  The thrust enhancement mechanism is
      simply that, for a given amount of energy, you can get more thrust with
      a lot of mass at a low speed than with less mass at high speed (because
      kinetic energy has velocity squared, but thrust depends on momentum,
      which doesn't).  Fast exhaust is preferred for rockets because they need
      to go fast and carry their reaction mass with them -- but pop-pop boats
      don't go fast, no matter how much we might want them to, and they use
      the water they float in as reaction mass, so arranging to entrain extra
      water in the thrust stream will enhance thrust, without enhancing the
      "negative thrust" of the intake stroke -- exactly as it does with a
      Lockwood-Hiller valveless pulse jet.

      I'd be interested to see the same thing built with thin wall aluminum
      tube, sanded thin at the leading and trailing edges, and including the
      ability to compare performance with and without the augmenter -- I'd bet
      you get between 20% and 80% increase in thrust, measured by the beam or
      draft of the boat (same waterline length) that can be pushed up to hull
      speed.

      Daryl wrote:
      > He has the "How not" part right. The "how to" has serious flaws and I
      > cannot believe that it worked as good as claimed. Maybe that is why there is a disclaimer.
      >
      > --- In pop-pop-steamboats@yahoogroups.com, "zoomkat"<Zoomkat@...>  wrote:
      >>
      >> Interesting pop pop boat engine experiments.
      >>
      >> http://www.instructables.com/id/How-Not-to-Build-A-Valved-Pop-Pop-Boat/
      >> http://www.instructables.com/id/How-To-Make-a-Valved-Pop-Pop-Boat/
      >>
      >

      --
      If, through hard work and perseverance, you finally get what you want,
      it's probably a sign you weren't dreaming big enough.

      Donald Qualls, aka The Silent Observer   http://silent1.home.netcom.com

      Opinions expressed are my own -- take them for what they're worth
      and don't expect them to be perfect.


      ------------------------------------

    • Frank McNeill
      Hi Donald and Daryl, Your discussion of thrust augmenters reminded me of a vacuum gadget that was used to convey strips of paper trimmed from the edges of
      Message 2 of 10 , Jul 6, 2011
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        Hi Donald and Daryl,

        Your discussion of thrust augmenters reminded me of a vacuum gadget that was used to convey strips of paper trimmed from the edges of craft paper used to make single and multiwall bags in one of the umpteen places where I have been employed during my long and not very profitable career. Doesn't have much to do with pop-pop boats, but might suggest something for thrust augmentation.
        Go to http://www.foxvalve.com/video_eductor.aspx and cross your fingers, because cut and paste procedures don't always work on my wretched iPad.

        Old Frank

        --- In pop-pop-steamboats@yahoogroups.com, Daryl Foster <darylcanada73@...> wrote:
        >
        > As always Donald, you make me think and I will think on your comments. I would like to test augmenters, preferably on my 7 tube engines as I have several that are near identical and are comparatively (for putt putts) excellent performers by all measures. Guess I need a way to mass produce them.
        >
        > A couple of questions first though. The velocity of a putt putt engine power stroke is not very high but is improved considerably with the use of nozzles. What is the velocity of a pulse jet engine exhaust? 
        >  
        > Could you clarify your last paragraph:-" I'd bet
        > you get between 20% and 80% increase in thrust, measured by the beam or
        > draft of the boat (same waterline length) that can be pushed up to hull
        > speed"  Reaching hull speed with a putt putt seems unlikely without a very major break through if that is what you are suggesting. .
        >
        >
        > --- On Tue, 7/5/11, Donald Qualls <silent1@...> wrote:
        >
        >
        > From: Donald Qualls <silent1@...>
        > Subject: Re: [pop-pop-steamboats] Re: Interesting pop pop boat engine experiments.
        > To: pop-pop-steamboats@yahoogroups.com
        > Received: Tuesday, July 5, 2011, 8:39 PM
        >
        >
        > I think he's deeply confused concerning the "valve-like" operation of an
        > augmenter, but I'd actually expect a correctly proportioned augmenter to
        > increase the thrust of a pop-pop.  The thrust enhancement mechanism is
        > simply that, for a given amount of energy, you can get more thrust with
        > a lot of mass at a low speed than with less mass at high speed (because
        > kinetic energy has velocity squared, but thrust depends on momentum,
        > which doesn't).  Fast exhaust is preferred for rockets because they need
        > to go fast and carry their reaction mass with them -- but pop-pop boats
        > don't go fast, no matter how much we might want them to, and they use
        > the water they float in as reaction mass, so arranging to entrain extra
        > water in the thrust stream will enhance thrust, without enhancing the
        > "negative thrust" of the intake stroke -- exactly as it does with a
        > Lockwood-Hiller valveless pulse jet.
        >
        > I'd be interested to see the same thing built with thin wall aluminum
        > tube, sanded thin at the leading and trailing edges, and including the
        > ability to compare performance with and without the augmenter -- I'd bet
        > you get between 20% and 80% increase in thrust, measured by the beam or
        > draft of the boat (same waterline length) that can be pushed up to hull
        > speed.
        >
        > Daryl wrote:
        > > He has the "How not" part right. The "how to" has serious flaws and I
        > > cannot believe that it worked as good as claimed. Maybe that is why there is a disclaimer.
        > >
        > > --- In pop-pop-steamboats@yahoogroups.com, "zoomkat"<Zoomkat@>  wrote:
        > >>
        > >> Interesting pop pop boat engine experiments.
        > >>
        > >> http://www.instructables.com/id/How-Not-to-Build-A-Valved-Pop-Pop-Boat/
        > >> http://www.instructables.com/id/How-To-Make-a-Valved-Pop-Pop-Boat/
        > >>
        > >
        >
        > --
        > If, through hard work and perseverance, you finally get what you want,
        > it's probably a sign you weren't dreaming big enough.
        >
        > Donald Qualls, aka The Silent Observer   http://silent1.home.netcom.com
        >
        > Opinions expressed are my own -- take them for what they're worth
        > and don't expect them to be perfect.
        >
        >
        > ------------------------------------
        >
      • Frank McNeill
        P/S Now that was weird, I can t watch stuff on YouTube because jackass Steve Jobs doesn t allow anything that uses Adobe Flash, but the video on the
        Message 3 of 10 , Jul 6, 2011
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          P/S Now that was weird, I can't watch stuff on YouTube because jackass Steve Jobs doesn't allow anything that uses Adobe Flash, but the video on the foxvalve.com video worked the way YouTube stuff is supposed to work! Make a note of this, don't ever buy a gdblanketyblank iPad!!!

          --- In pop-pop-steamboats@yahoogroups.com, "Frank McNeill" <frankmcneilll@...> wrote:
          >
          > Hi Donald and Daryl,
          >
          > Your discussion of thrust augmenters reminded me of a vacuum gadget that was used to convey strips of paper trimmed from the edges of craft paper used to make single and multiwall bags in one of the umpteen places where I have been employed during my long and not very profitable career. Doesn't have much to do with pop-pop boats, but might suggest something for thrust augmentation.
          > Go to http://www.foxvalve.com/video_eductor.aspx and cross your fingers, because cut and paste procedures don't always work on my wretched iPad.
          >
          > Old Frank
          >
          > --- In pop-pop-steamboats@yahoogroups.com, Daryl Foster <darylcanada73@> wrote:
          > >
          > > As always Donald, you make me think and I will think on your comments. I would like to test augmenters, preferably on my 7 tube engines as I have several that are near identical and are comparatively (for putt putts) excellent performers by all measures. Guess I need a way to mass produce them.
          > >
          > > A couple of questions first though. The velocity of a putt putt engine power stroke is not very high but is improved considerably with the use of nozzles. What is the velocity of a pulse jet engine exhaust? 
          > >  
          > > Could you clarify your last paragraph:-" I'd bet
          > > you get between 20% and 80% increase in thrust, measured by the beam or
          > > draft of the boat (same waterline length) that can be pushed up to hull
          > > speed"  Reaching hull speed with a putt putt seems unlikely without a very major break through if that is what you are suggesting. .
          > >
          > >
          > > --- On Tue, 7/5/11, Donald Qualls <silent1@> wrote:
          > >
          > >
          > > From: Donald Qualls <silent1@>
          > > Subject: Re: [pop-pop-steamboats] Re: Interesting pop pop boat engine experiments.
          > > To: pop-pop-steamboats@yahoogroups.com
          > > Received: Tuesday, July 5, 2011, 8:39 PM
          > >
          > >
          > > I think he's deeply confused concerning the "valve-like" operation of an
          > > augmenter, but I'd actually expect a correctly proportioned augmenter to
          > > increase the thrust of a pop-pop.  The thrust enhancement mechanism is
          > > simply that, for a given amount of energy, you can get more thrust with
          > > a lot of mass at a low speed than with less mass at high speed (because
          > > kinetic energy has velocity squared, but thrust depends on momentum,
          > > which doesn't).  Fast exhaust is preferred for rockets because they need
          > > to go fast and carry their reaction mass with them -- but pop-pop boats
          > > don't go fast, no matter how much we might want them to, and they use
          > > the water they float in as reaction mass, so arranging to entrain extra
          > > water in the thrust stream will enhance thrust, without enhancing the
          > > "negative thrust" of the intake stroke -- exactly as it does with a
          > > Lockwood-Hiller valveless pulse jet.
          > >
          > > I'd be interested to see the same thing built with thin wall aluminum
          > > tube, sanded thin at the leading and trailing edges, and including the
          > > ability to compare performance with and without the augmenter -- I'd bet
          > > you get between 20% and 80% increase in thrust, measured by the beam or
          > > draft of the boat (same waterline length) that can be pushed up to hull
          > > speed.
          > >
          > > Daryl wrote:
          > > > He has the "How not" part right. The "how to" has serious flaws and I
          > > > cannot believe that it worked as good as claimed. Maybe that is why there is a disclaimer.
          > > >
          > > > --- In pop-pop-steamboats@yahoogroups.com, "zoomkat"<Zoomkat@>  wrote:
          > > >>
          > > >> Interesting pop pop boat engine experiments.
          > > >>
          > > >> http://www.instructables.com/id/How-Not-to-Build-A-Valved-Pop-Pop-Boat/
          > > >> http://www.instructables.com/id/How-To-Make-a-Valved-Pop-Pop-Boat/
          > > >>
          > > >
          > >
          > > --
          > > If, through hard work and perseverance, you finally get what you want,
          > > it's probably a sign you weren't dreaming big enough.
          > >
          > > Donald Qualls, aka The Silent Observer   http://silent1.home.netcom.com
          > >
          > > Opinions expressed are my own -- take them for what they're worth
          > > and don't expect them to be perfect.
          > >
          > >
          > > ------------------------------------
          > >
          >
        • Donald Qualls
          ... As with anything else in the homebuilt realm, it varies considerably (and is a bit hard to measure, since the exhaust is also hot), but the best of them
          Message 4 of 10 , Jul 8, 2011
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            Daryl Foster wrote:
            >
            >
            > What is the velocity of a pulse jet engine exhaust?

            As with anything else in the homebuilt realm, it varies considerably
            (and is a bit hard to measure, since the exhaust is also hot), but the
            best of them will put out several times the volume of a leaf blower at a
            similar velocity without augmentation.

            > Could you clarify your last paragraph:-" I'd bet
            > you get between 20% and 80% increase in thrust, measured by the beam or
            > draft of the boat (same waterline length) that can be pushed up to hull
            > speed" Reaching hull speed with a putt putt seems unlikely without a
            > very major break through if that is what you are suggesting.

            I was mostly suggesting hull size vs. speed as a means of measuring the
            thrust increase due to the augmenter. An alternate would be to measure
            the size of a drag paddle (just a flat plate in the water at the boat's
            transom) that reduces the augmented boat's speed to that of the same
            boat without augmentation. You'd run the boat with the drag paddle
            installed, but raised out of the water (so the weight is as nearly the
            same as possible), then mount the augmenter(s) and run the boat again,
            increasing the depth of the drag paddle each run until the speed is the
            same as in the control run. Knowing the area of the drag paddle and a
            little hydrodynamic math (flat plate drag is one of the simplest
            calculations) will let you calculate how much extra thrust you're
            getting (if any).

            --
            If, through hard work and perseverance, you finally get what you want,
            it's probably a sign you weren't dreaming big enough.

            Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com

            Opinions expressed are my own -- take them for what they're worth
            and don't expect them to be perfect.
          • Daryl
            Thanks Donald. I measure force now at bollard pull with the setup shown in a photo in my photo album. In this photo the engine is mounted on a testing raft
            Message 5 of 10 , Jul 9, 2011
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              Thanks Donald. I measure force now at bollard pull with the setup shown in a photo in my photo album. In this photo the engine is mounted on a testing "raft" that adjusts to most size engines. If using a boat it is attached to the gram scale and if the boat is light or resonates a lot baffles are attached to reduce the shuttle. The boat could easily be weighted to equal the weight when then augmenters are installed. Due to the pulsing of the engine an average has to be decided on. To improve accuracy I video the scale when the engine is running. When played back at high speed the strobe effect usually pegs the pointer in a very narrow range. Do you think that your suggested testing method would be more accurate?

              --- In pop-pop-steamboats@yahoogroups.com, Donald Qualls <silent1@...> wrote:
              >
              > Daryl Foster wrote:
              > >
              > >
              > > What is the velocity of a pulse jet engine exhaust?
              >
              > As with anything else in the homebuilt realm, it varies considerably
              > (and is a bit hard to measure, since the exhaust is also hot), but the
              > best of them will put out several times the volume of a leaf blower at a
              > similar velocity without augmentation.
              >
              > > Could you clarify your last paragraph:-" I'd bet
              > > you get between 20% and 80% increase in thrust, measured by the beam or
              > > draft of the boat (same waterline length) that can be pushed up to hull
              > > speed" Reaching hull speed with a putt putt seems unlikely without a
              > > very major break through if that is what you are suggesting.
              >
              > I was mostly suggesting hull size vs. speed as a means of measuring the
              > thrust increase due to the augmenter. An alternate would be to measure
              > the size of a drag paddle (just a flat plate in the water at the boat's
              > transom) that reduces the augmented boat's speed to that of the same
              > boat without augmentation. You'd run the boat with the drag paddle
              > installed, but raised out of the water (so the weight is as nearly the
              > same as possible), then mount the augmenter(s) and run the boat again,
              > increasing the depth of the drag paddle each run until the speed is the
              > same as in the control run. Knowing the area of the drag paddle and a
              > little hydrodynamic math (flat plate drag is one of the simplest
              > calculations) will let you calculate how much extra thrust you're
              > getting (if any).
              >
              > --
              > If, through hard work and perseverance, you finally get what you want,
              > it's probably a sign you weren't dreaming big enough.
              >
              > Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com
              >
              > Opinions expressed are my own -- take them for what they're worth
              > and don't expect them to be perfect.
              >
            • Frank McNeill
              For related stuff go to: http://www.cogulus.com/archimedes/essays/essay1.html
              Message 6 of 10 , Jul 9, 2011
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                For related stuff go to:
                http://www.cogulus.com/archimedes/essays/essay1.html
                --- In pop-pop-steamboats@yahoogroups.com, "Daryl" <darylcanada73@...> wrote:
                >
                > Thanks Donald. I measure force now at bollard pull with the setup shown in a photo in my photo album. In this photo the engine is mounted on a testing "raft" that adjusts to most size engines. If using a boat it is attached to the gram scale and if the boat is light or resonates a lot baffles are attached to reduce the shuttle. The boat could easily be weighted to equal the weight when then augmenters are installed. Due to the pulsing of the engine an average has to be decided on. To improve accuracy I video the scale when the engine is running. When played back at high speed the strobe effect usually pegs the pointer in a very narrow range. Do you think that your suggested testing method would be more accurate?
                >
                > --- In pop-pop-steamboats@yahoogroups.com, Donald Qualls <silent1@> wrote:
                > >
                > > Daryl Foster wrote:
                > > >
                > > >
                > > > What is the velocity of a pulse jet engine exhaust?
                > >
                > > As with anything else in the homebuilt realm, it varies considerably
                > > (and is a bit hard to measure, since the exhaust is also hot), but the
                > > best of them will put out several times the volume of a leaf blower at a
                > > similar velocity without augmentation.
                > >
                > > > Could you clarify your last paragraph:-" I'd bet
                > > > you get between 20% and 80% increase in thrust, measured by the beam or
                > > > draft of the boat (same waterline length) that can be pushed up to hull
                > > > speed" Reaching hull speed with a putt putt seems unlikely without a
                > > > very major break through if that is what you are suggesting.
                > >
                > > I was mostly suggesting hull size vs. speed as a means of measuring the
                > > thrust increase due to the augmenter. An alternate would be to measure
                > > the size of a drag paddle (just a flat plate in the water at the boat's
                > > transom) that reduces the augmented boat's speed to that of the same
                > > boat without augmentation. You'd run the boat with the drag paddle
                > > installed, but raised out of the water (so the weight is as nearly the
                > > same as possible), then mount the augmenter(s) and run the boat again,
                > > increasing the depth of the drag paddle each run until the speed is the
                > > same as in the control run. Knowing the area of the drag paddle and a
                > > little hydrodynamic math (flat plate drag is one of the simplest
                > > calculations) will let you calculate how much extra thrust you're
                > > getting (if any).
                > >
                > > --
                > > If, through hard work and perseverance, you finally get what you want,
                > > it's probably a sign you weren't dreaming big enough.
                > >
                > > Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com
                > >
                > > Opinions expressed are my own -- take them for what they're worth
                > > and don't expect them to be perfect.
                > >
                >
              • Donald Qualls
                ... I very strongly doubt it -- but it would be a lot easier to set up for those who don t have a scale that reads in fractional grams. -- If, through hard
                Message 7 of 10 , Jul 9, 2011
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                  Daryl wrote:
                  > Do you think that
                  > your suggested testing method would be more accurate?
                  >

                  I very strongly doubt it -- but it would be a lot easier to set up for
                  those who don't have a scale that reads in fractional grams.

                  --
                  If, through hard work and perseverance, you finally get what you want,
                  it's probably a sign you weren't dreaming big enough.

                  Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com

                  Opinions expressed are my own -- take them for what they're worth
                  and don't expect them to be perfect.
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