Re: Big pop-pop engine
- Water temp not an influence...interesting,
the other idea I had regarding the loss of pulse on my test stand
was possible over heating of boiler, this may be the culprit because
I use "sterno" type caned heat on the test stand and charcoal in the
boat. When the engine stoped pulseing I removed the heat and a
munite or so later it pulsed several times and then stopped again,
possibly cooling down through optimim temp range to below it.
I noticed in the video of German pop pop a clear section of tubeing
in the pulse pipe, possibly isolating heat transfer from the boiler
to the rest of the pipe? Would this bring liquid water directly into
the boiler causing a larger pulse?
When my barrel boiler is running I think the boiler is full of steam
and the water/steam boiling point is actually 5-6 inches down the
I plan on attempting to isolate the boiler from the pulse pipe
(temperature wise) and see how this affects boiler opperation.
keep on popping!
--- In email@example.com, "Jean-Yves Renaud"
> Hi Frank (your message #703), Dan (#701), Russ (#696), Vance
> Frequency. I confirm what observed Dan. According to my
> with a 3ft pipe his engine should oscillate at 1.0Hz. With a 5ftpipe it
> should oscillate at 0.8Hz.above all
> The amount of energy which is delivered by the engine depends
> on the water mass in movement and on the stroke. The best strokethat
> corresponds to the use of the full length of the pipe; which means
> the meniscus goes from the top to the bottom. If you use the rightexperimentation.
> heating power for a long time (You have to be patient. Sometimes it
> needs several hours.) you will get this best running.
> The best heating power is something to be determined by
> It is the maximum permanent power. For every engine there is such apower is
> specific power. An engine can run for a long time only if the
> within a certain range (specific to each engine). Below it doesn'tevolves
> start. Above, it goes to burnout. In between the delivered power
> linearily with the heating power. I wrote a short report on that.You
> can see it on www.eclecticspace.net. This not my web site (I havenone),
> but most of my reports are on it. Click on "Pop-pop" and then onfactor
> "For English speaking " and then on "To know more.
> Jean-Yves' page".
> The energy in itself is not a major factor. I think that the main
> is the momentum. It depends on the flow and the velocity at thenozzle
> outlet (the nozzle being generally only a straight cut of thepipe).
> Then, we have to think about the "useful energy". It is the one
> which propels the boat. Obviously, there is none during the
> phase (when the pipe is sucking). And there is none as long as thejet
> velocity is lower than the boat one. Therefore, it is difficult tosay
> what is the best engine-hull adaptation.getting any
> Influence of the water temperature.
> I ran some tests on the influence of the temperature without
> significant result. On that matter I exchanged some informationwith
> another pop-pop specialist (Guus who lives in Holland) and he rantemperature of
> similar tests with a wider range of temperature. Hereafter are his
> words: <<After a running time of more than 90 minutes the
> the water in my test bench was 31 degrees C. While the engine wasstill
> running, I warmed the water with an electric heater warm up to 40well as
> degrees. The result was the same as yours, the engines runned as
> before. Then I went on heating and stopped when the temperaturewas 55
> degrees. Even then the engines were running well. >>. Obviously,be
> according to the laws of thermodynamics the delivered power should
> better when the temperature difference between hot source and coldinfluence
> source is big. However, two factors render this temperature
> very weak.who
> 1°) The efficiency of a pop-pop engine is pathetic. The best one I
> measured was something as 0.1%.
> 2°) Most of the thermodynamic process occurs at the interface (the
> meniscus) and the temperature of the water just below is close to
> 100°C whatever the one into the tank.
> Some complementary experiments were done by Christophe (a student
> contacted me last year) with a glass engine using methyl alcoholinstead
> of water to get a lower boiling temperature. Therefore, thedifference
> between hot source and cold one was only approx 40°C and the enginewith
> worked apparently as it would have worked with water.
> I stop there. This could (should?) involve complementary exchanges
> some of you
> Best wishes.
- Hi dan,
I'm presently travelling far from my pop-pop engines. The pipe of the big engine is approx 75cm long. It is going up for the first 10cm and then it is straight and slightluy inclined down. More details in a couple of weeks when I am back to my "laboratory".
> Message du 19/03/07 00:15
> De : "danoyes1" <danoyes1@...>
> A : firstname.lastname@example.org
> Copie à :
> Objet : [pop-pop-steamboats] Re: Big pop-pop engine
> Hi all
> Jean I look foreward to hearing the test results you get for your
> big drum evaporator. how long is the pulse pipe on your new engine?
> it's good to hear that it had such a powerfull thrust pulse and ran
> without incident.
> --- In email@example.com, "Slater Harrison"
> <Sharrison@...> wrote:
> > I was just looking at Dan's and Jean-Yves' pictures. Wow! I've been
> > following pop pop engines for a couple of decades and I knew of two
> > types: the diaphragm type and the coil type. I've never seen
> > like the hammer head! Where did this design come from? How long
> has it
> > been around?
> > Slater
> > -----Original Message-----
> > From: firstname.lastname@example.org
> > [mailto:email@example.com] On Behalf Of Jean-Yves
> > Renaud
> > Sent: Thursday, March 15, 2007 1:58 PM
> > To: firstname.lastname@example.org
> > Subject: [pop-pop-steamboats] Re: Big pop-pop engine
> > Hi all,
> > Up to now, my biggest pop-pop engine had a pipe of ID 10mm, and
> > engine was far from optimized because at that time I didn't know
> as much
> > as I know today. Encouraged by Dan's messages and by the pictures
> of his
> > engines, I built a big one. I wanted to call it the 4 dollar engine
> > because 2 coins of 2 Canadian $ would have been perfect to close
> > evaporator. Unfortunately (that's the appropriate word) I had only
> > coin left over from my last visit in Canada. I tried the Italian
> > coin. It fitted too...but I had only one. Therefore, as I didn't
> want to
> > be responsible of a war between Canada and Italy (with all the
> > corresponding messages on the forum!!!), I decided to build 2
> > caps by myself. (see the photo album).
> > Two hours later the engine ran at the first attempt. The
> evaporator ID
> > is 28mm and the pipe ID is 12mm. The engine seems very powerful.
> > water level in my (small) test tank (approx 15cm x 30cm) was 30mm
> > the top, but the waves succeeded to flood my work bench.
> > When I have time (i.e. probably not before next month) I will test
> > engine with appropriate measuring instruments and I'll let you
> > Jean-Yves