Hello Mikhail,
Thank you for that inlet OD measurement! I am only in a rush, because you have so little time before you fly off to Maui.
While you are there, try to visit Hana, which is located on the east end of the island. Well off the beaten path, but Nice!
Best regards,
Störgröße M.
__________________
"If we can not look to Chaos Theory for the Answer, then we are lost. And it is handy for pulsejets, too" -- Störgröße M.
Nanosoft: New Chinese Project
Moderator: Mike Everman
-
milisavljevic
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- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
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milisavljevic
- Posts: 855
- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
Revised dimensions for your review!
Good morning, Mikhail!
Please take a look at the attached drawing. You will find your original and a revised layout. It is _important_ for you
to note that the dimensions included with the revised layout _do not_ match the ones that I have described before!
If you wish to use my recommendations, please follow the dimensions from the revised layout, and disregard my
previous posts. This is very important. I would also ask that you do not "mix and match" recommendations, both
those I have provided and those offered by others. I stand behind my calculations, recommendations, and all of
my "predictions", which I offer to you as a "matched set". In any event, I have done my best to help your work!
From the revised drawing, you will note that the combustor length has increased to 120 mm; however, this is not
measured from the apex of the combustor cap, but from the spark gap; I assume it protrudes into the combustor
a short distance. If the spark gap is flush with the apex, well, then the 120 mm OA length does include the apex.
In a similar way, the new OA length of 850 mm is measured from the spark gap. All dimensions were modeled to
within 0.5 mm; it is important to build to this. If you do err in construction, then it is best to err on the long side!
Btw, if your original intention was to stay inside the 32-33 inch limitation, of the "Great Chinese Pulsejet Shootout",
then I suggest that you use this project as a springboard to building an even more powerful pulsejet. I decided to
run out the length to 850 mm based upon the dimensions you had already built to, e.g., an 84.8 mm exit diameter.
Okay, now for the performance specifications, which I have to "guarantee". Naturally, I will work with you to solve
any problems with fuel delivery and injector design (if you wish!). Snecma researchers determined that up to 20%
of the maximum developed thrust may be lost from sub-optimal injector placement, or poor fuel delivery problems.
Stationary performance specifications based upon ICAO standard day, sea level, 288 K:
(a) maximum continuous thrust rating = 5.0 kgf (11.0 lbf, 49 N);
(b) stable characteristic frequency = 302 Hz +|- 2 Hz (@ 700 K);
(c) specific fuel consumption = 2.3 kg/kgf/hr @ maximum thrust, equivalence ratio = 1.0;
(d) specific fuel consumption = 3.0 kg/kgf/hr @ maximum thrust, equivalence ratio = 1.3;
(e) maximum thrust saturation = 85% with an inlet-exhaust thrust split of 23% by 77%;
Of course, I have an ability to determine additional performance data, e.g., SFC at other thrust levels or varying
ambient conditions, including changes in altitude, and airspeed. A variety of common fuels may also be modeled.
If you have any questions or comments, please post them here and I will respond to you as soon as possible, okay?
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
Please take a look at the attached drawing. You will find your original and a revised layout. It is _important_ for you
to note that the dimensions included with the revised layout _do not_ match the ones that I have described before!
If you wish to use my recommendations, please follow the dimensions from the revised layout, and disregard my
previous posts. This is very important. I would also ask that you do not "mix and match" recommendations, both
those I have provided and those offered by others. I stand behind my calculations, recommendations, and all of
my "predictions", which I offer to you as a "matched set". In any event, I have done my best to help your work!
From the revised drawing, you will note that the combustor length has increased to 120 mm; however, this is not
measured from the apex of the combustor cap, but from the spark gap; I assume it protrudes into the combustor
a short distance. If the spark gap is flush with the apex, well, then the 120 mm OA length does include the apex.
In a similar way, the new OA length of 850 mm is measured from the spark gap. All dimensions were modeled to
within 0.5 mm; it is important to build to this. If you do err in construction, then it is best to err on the long side!
Btw, if your original intention was to stay inside the 32-33 inch limitation, of the "Great Chinese Pulsejet Shootout",
then I suggest that you use this project as a springboard to building an even more powerful pulsejet. I decided to
run out the length to 850 mm based upon the dimensions you had already built to, e.g., an 84.8 mm exit diameter.
Okay, now for the performance specifications, which I have to "guarantee". Naturally, I will work with you to solve
any problems with fuel delivery and injector design (if you wish!). Snecma researchers determined that up to 20%
of the maximum developed thrust may be lost from sub-optimal injector placement, or poor fuel delivery problems.
Stationary performance specifications based upon ICAO standard day, sea level, 288 K:
(a) maximum continuous thrust rating = 5.0 kgf (11.0 lbf, 49 N);
(b) stable characteristic frequency = 302 Hz +|- 2 Hz (@ 700 K);
(c) specific fuel consumption = 2.3 kg/kgf/hr @ maximum thrust, equivalence ratio = 1.0;
(d) specific fuel consumption = 3.0 kg/kgf/hr @ maximum thrust, equivalence ratio = 1.3;
(e) maximum thrust saturation = 85% with an inlet-exhaust thrust split of 23% by 77%;
Of course, I have an ability to determine additional performance data, e.g., SFC at other thrust levels or varying
ambient conditions, including changes in altitude, and airspeed. A variety of common fuels may also be modeled.
If you have any questions or comments, please post them here and I will respond to you as soon as possible, okay?
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
-
milisavljevic
- Posts: 855
- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
re: Revised dimensions for your review!
Hello Mikhail,
If and when you have a chance to modify your pulsejet, here is an interesting experiment for you to attempt:
(a) achieve an initial stable resonance and self-sustaining operation, at a mid-level thrust setting, e.g., 50%;
(b) reduce the thrust setting to approximately 10%;
(c) block off one of the two inlets; how is up to you;
(d) observe for effect, and if the duct is still running,
(e) attempt to slowly increase throttle setting while
(f) observing for effect; note the throttle setting if, and when, flame-out occurs.
The model predicts that the engine will quickly flame-out if you attempt to advance the throttle setting much
beyond 20%. Of course, any method used to block off the inlet must affect things; I can not be more specific.
If the above is true, we now have yet another way to obtain Larry-sized thrust from a duct with dimensions
that suggest a capacity to develop five to ten times (5x-10x) as much thrust, but for some reason, does not.
Without spoon-feeding you or the forum, I can tell you that a careful study of this phenomenon will help you.
Best regards,
Störgröße M.
__________________
"In the event of colour-blindness, please download this alternate attachment for your viewing pleasure." -- Störgröße M.
If and when you have a chance to modify your pulsejet, here is an interesting experiment for you to attempt:
(a) achieve an initial stable resonance and self-sustaining operation, at a mid-level thrust setting, e.g., 50%;
(b) reduce the thrust setting to approximately 10%;
(c) block off one of the two inlets; how is up to you;
(d) observe for effect, and if the duct is still running,
(e) attempt to slowly increase throttle setting while
(f) observing for effect; note the throttle setting if, and when, flame-out occurs.
The model predicts that the engine will quickly flame-out if you attempt to advance the throttle setting much
beyond 20%. Of course, any method used to block off the inlet must affect things; I can not be more specific.
If the above is true, we now have yet another way to obtain Larry-sized thrust from a duct with dimensions
that suggest a capacity to develop five to ten times (5x-10x) as much thrust, but for some reason, does not.
Without spoon-feeding you or the forum, I can tell you that a careful study of this phenomenon will help you.
Best regards,
Störgröße M.
__________________
"In the event of colour-blindness, please download this alternate attachment for your viewing pleasure." -- Störgröße M.
-
Eric
- Posts: 1859
- Joined: Sat Oct 04, 2003 1:17 am
- Antipspambot question: 0
- Location: United States
- Contact:
re: Nanosoft: New Chinese Project
Perhaps you should just ignore everyone’s comments and remarks about what dimensions to use and get out your white (and slightly burnt) mad scientist lab coat.
When building an entirely new design type I usually start of with the engine as basic as possible. I use theory to get a theoretical value of what the dimensions "should" be (but I keep in mind that these might also be completely wrong), and add a bit of length to the intakes and tailpipe for real world tuning. I try to start the engine with different air positions, move the fuel injectors around and note any changes in behavior when I do these things.
If the engine makes any noise at all, I think about the changes in behavior and decide if I should take a bit of length off the intake or tailpipe or both or some other change, and reduce or increase the lengths in small increments doing a quick retest in between, still noting any changes in behavior I observe.
Since your engine is already fully made and doesn’t have extra length start off with simple changes, like playing around with the intake flares, and the fuel injectors until you get the current design to what you think is its maximum potential. Do each thing one at a time, and mark down any changes in behavior you observe and if there are significant changes maybe take a sound sampling, but make sure to take each sampling from the same exact spot in relation to the engine. If the engine still doesn’t run then proceed to the next step:
Get a notebook, document everything about the current engine configuration and all your observations, and take video / sound samples of all attempts, and theorize what is wrong with the engine, and think of a way that might fix it.
It doesn’t matter if you don’t really have a clue what is wrong, or how to go about fixing it, just create a plan and then test it out to verify or disprove your plan.
If the changes improve performance a bit, think about it and try to figure out why it improved performance, and if you can increase it even more. If it failed to improve anything or made it worse, you still gain precious real world experimental data.
Keep cutting and adding bits of length to various parts, and moving the injectors around to see if the best fuel injection spot has also changed. If you write down all your results, even if you didn’t get the engine to run you still have a lot of information and experience which no amount of theory or math could get you.
You might notice "It runs better with one intake blocked than with two open" and from that you can get a whole bunch of simple things to test, which you already have to some extent, such as use the smaller diameter intakes, or perhaps just one intake for now. You might also decide to try Kentfield style adjustable length intakes to see if the lengths are off and use various different inner diameter adjustable intakes.
If you get to the point where enough is enough and you want to kick and pound the engine into a pile of scrap, you still have that notebook full of observations that you can use to design a new engine, and perhaps change some of the things that were fundamentally flawed in the design.
And when you build that new engine, and follow the same experimental process and gain even more data, you will start to notice things that you never noticed before. The more engines you successfully design and build, testing each one thoroughly, the easier it will be for you to design engines that are successful on the first try and can reach theoretical maximums with just a bit of injector tweaking.
You are obviously already doing this process to some extent, or you probably wouldn’t have designed your own engine. I say follow your own theories, prove or disprove them through experimentation, and become the expert that others will need help from.
It may take a little longer but in the long run it will pay off a thousand fold.
Eric
When building an entirely new design type I usually start of with the engine as basic as possible. I use theory to get a theoretical value of what the dimensions "should" be (but I keep in mind that these might also be completely wrong), and add a bit of length to the intakes and tailpipe for real world tuning. I try to start the engine with different air positions, move the fuel injectors around and note any changes in behavior when I do these things.
If the engine makes any noise at all, I think about the changes in behavior and decide if I should take a bit of length off the intake or tailpipe or both or some other change, and reduce or increase the lengths in small increments doing a quick retest in between, still noting any changes in behavior I observe.
Since your engine is already fully made and doesn’t have extra length start off with simple changes, like playing around with the intake flares, and the fuel injectors until you get the current design to what you think is its maximum potential. Do each thing one at a time, and mark down any changes in behavior you observe and if there are significant changes maybe take a sound sampling, but make sure to take each sampling from the same exact spot in relation to the engine. If the engine still doesn’t run then proceed to the next step:
Get a notebook, document everything about the current engine configuration and all your observations, and take video / sound samples of all attempts, and theorize what is wrong with the engine, and think of a way that might fix it.
It doesn’t matter if you don’t really have a clue what is wrong, or how to go about fixing it, just create a plan and then test it out to verify or disprove your plan.
If the changes improve performance a bit, think about it and try to figure out why it improved performance, and if you can increase it even more. If it failed to improve anything or made it worse, you still gain precious real world experimental data.
Keep cutting and adding bits of length to various parts, and moving the injectors around to see if the best fuel injection spot has also changed. If you write down all your results, even if you didn’t get the engine to run you still have a lot of information and experience which no amount of theory or math could get you.
You might notice "It runs better with one intake blocked than with two open" and from that you can get a whole bunch of simple things to test, which you already have to some extent, such as use the smaller diameter intakes, or perhaps just one intake for now. You might also decide to try Kentfield style adjustable length intakes to see if the lengths are off and use various different inner diameter adjustable intakes.
If you get to the point where enough is enough and you want to kick and pound the engine into a pile of scrap, you still have that notebook full of observations that you can use to design a new engine, and perhaps change some of the things that were fundamentally flawed in the design.
And when you build that new engine, and follow the same experimental process and gain even more data, you will start to notice things that you never noticed before. The more engines you successfully design and build, testing each one thoroughly, the easier it will be for you to design engines that are successful on the first try and can reach theoretical maximums with just a bit of injector tweaking.
You are obviously already doing this process to some extent, or you probably wouldn’t have designed your own engine. I say follow your own theories, prove or disprove them through experimentation, and become the expert that others will need help from.
It may take a little longer but in the long run it will pay off a thousand fold.
Eric
Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases
re: Nanosoft: New Chinese Project
I've got my work cut out for me. It's 2:00 now and at 6:00 I have a choir concert. Tomorrow I go up to Portland right after school to spend the night there before going to the airport on Saturday. So I will try my hardest to finish and run the engine today. Thanks milisavljevic.
Mikhail Jones
Mikhail Jones
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milisavljevic
- Posts: 855
- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
Down to the wire.
Hello Mikhail!
My apologies that we have run out of time. Why not let the project hibernate until you have returned from Maui?
As much as I would like to see you finish it now, we have to acknowledge that sometimes, "life gets in the way".
Have a safe and wonderful trip, and Happy Hawaiian Holidays!
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
My apologies that we have run out of time. Why not let the project hibernate until you have returned from Maui?
As much as I would like to see you finish it now, we have to acknowledge that sometimes, "life gets in the way".
Have a safe and wonderful trip, and Happy Hawaiian Holidays!
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
re: Nanosoft: New Chinese Project
Well, I just got back from my Choir Concert (Went great!) and here is the update. I cut it close but made it. I finished making all the mods which took me just over 2 hours. The engine looks pretty good, not quite as clean and polished as before but good. I didn't have time to start or test it yet.
I don't think I will be able to sleep if I don't get it going. Hopefully tomorrow I will have an hour to spare so I can get it started. If not, it's no big deal it will just have to wait until after Hawaii. Can't wait.
Good Night.
Mikhail Jones
I don't think I will be able to sleep if I don't get it going. Hopefully tomorrow I will have an hour to spare so I can get it started. If not, it's no big deal it will just have to wait until after Hawaii. Can't wait.
Good Night.
Mikhail Jones
re: Nanosoft: New Chinese Project
Oh and by the way. I will post pictures tommorow as well.
Peace
Mikhail Jones
Peace
Mikhail Jones
-
milisavljevic
- Posts: 855
- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
Awesomely awesome!!
Hello Mikhail!
Great news, dude! Oh, how I hope that you have enough time tomorrow morning to attempt a test run.
And enough time for you to post a simple, "It runs!", or perhaps, "It's a dud." - how can I sleep tonight?
Christmas Eve arrived 9 days early this year... Thank you for this cool news, Mikhail. Have a great night.
Btw, if you do have time, a sound recording would be nice.
Peace,
M.
__________________
"Sir, that was not my dog".
Great news, dude! Oh, how I hope that you have enough time tomorrow morning to attempt a test run.
And enough time for you to post a simple, "It runs!", or perhaps, "It's a dud." - how can I sleep tonight?
Christmas Eve arrived 9 days early this year... Thank you for this cool news, Mikhail. Have a great night.
Btw, if you do have time, a sound recording would be nice.
Peace,
M.
__________________
"Sir, that was not my dog".
re: Nanosoft: New Chinese Project
I don't have much time but here is the report. It ran but not very well. The problem is the fuel injector placement. My propane tank wouldn't give enough gas to let it run and on liquid propane it was to hard to fuel it so it kept flaming out. Overaal very good results. My pictures came out blurring so i am not going to post them but when i get back i will give a full report and pictures and video. Yeah Winter break! See everyone in ten days.
Hopefully i will be able to find a computer to use to check up on the forum.
Bye
Mikhail Jones
Hopefully i will be able to find a computer to use to check up on the forum.
Bye
Mikhail Jones
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leo
- Posts: 380
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- Location: netherlands
- Contact:
re: Nanosoft: New Chinese Project
Very interesting can’t wait to see the outcome of this.
I’ am following it wit much expectation.
Leo.
I’ am following it wit much expectation.
Leo.
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milisavljevic
- Posts: 855
- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
Have a great trip!
Hello Mikhail,
Have a great trip! Thank you for the last minute heroics; we can sort out "what's what", and "what's not", once you return.
Btw, I set the model up for gasoline, not propane. I remember that you had easy access to the former, not so much the latter.
No matter. I will set up a parallel test cell for propane, and converge a solution. We can size the injectors after your return.
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
Have a great trip! Thank you for the last minute heroics; we can sort out "what's what", and "what's not", once you return.
Btw, I set the model up for gasoline, not propane. I remember that you had easy access to the former, not so much the latter.
No matter. I will set up a parallel test cell for propane, and converge a solution. We can size the injectors after your return.
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
-
milisavljevic
- Posts: 855
- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
Well, now that you mention it...
Most Gentle Ben,
Here is a message for you, and the silent readers, who may be following this thread with more than a casual interest:
This is a public forum... We all understand this. I am not concerned that Mikhail's test results, now, or upon his return,
may not match the output from my pulsejet model. I did not expect to score "a hole in one", for several reasons, and
not the least of these reasons is that we learn more from the mistakes we make... and not so much from our success.
__
More to the point, there are many contributing factors that can affect any results that Mikhail may eventually measure:
(a) the accuracy and repeatability of the thrust stand;
(b) the location and configuration of the fuel injectors;
(c) the precision with which the duct was assembled;
(d) the original, unaddressed deficiencies in the duct;
(e) the specific atmospheric data at the test location.
Upon Mikhail's return, I will work with him, to the extent that he is willing and|or interested, to identify, and as needed,
rectify any deficiencies relating to items (a) and (b). Wrt to item (c), if the "as-built" dimensions differ from the drawing,
then I will re-converge the model with the correct dimensions, just as I will re-converge the model for propane vapour.
Wrt item (d), these have been accounted for to the extent that I am aware of them. Finally, I will gather data for item
(e), e.g., the altitude at the test site, air pressure, temperature - even the humidity. Remember, JAC Kentfield tested,
or rather his graduate students tested various pulsejets from the University of Calgary at an altitude of over 1000 m.
To make things even more interesting, I deliberately targeted several arbitrary performance specifications, instead of
trying to "perfect" his original duct layout; this would require diameter changes, and in turn, make for a longer "re-fit".
For your reading pleasure, I have listed the arbitrary performance specifications:
(a) maximum static thrust = 5.0 kgf (that "0" is a sigificant digit);
(b) overall duct length = 850 mm (about 11 mm off the optimum);
(c) acoustic temperature = 697 K (I targeted and missed 700 K);
(d) characteristic frequency = 302 Hz (I wanted exactly 300 Hz);
And do not forget the fact that I unilaterally took diameter changes off the table.
__
You would do well to note that this model which I have constructed, and continue to improve upon, is only a reflection
of my own limited understanding of pulsed combustion, and its application in the production of thrust. It is not a piece
of shrink-wrapped software, but an inorganic extension of my mind (now that is a scary thought!). If, in the end, real
discrepancies exist between what it predicts and what is measured, then so much the better. An opportunity to learn
is more valuable to me at the end of the day. I will benefit, as will you and Mikhail. I will be pleased with any outcome!
(all of my cards are on the table, free from guesses, hack and pray, BS and TLAR; I say let the chips fall where they may)
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
Here is a message for you, and the silent readers, who may be following this thread with more than a casual interest:
This is a public forum... We all understand this. I am not concerned that Mikhail's test results, now, or upon his return,
may not match the output from my pulsejet model. I did not expect to score "a hole in one", for several reasons, and
not the least of these reasons is that we learn more from the mistakes we make... and not so much from our success.
__
More to the point, there are many contributing factors that can affect any results that Mikhail may eventually measure:
(a) the accuracy and repeatability of the thrust stand;
(b) the location and configuration of the fuel injectors;
(c) the precision with which the duct was assembled;
(d) the original, unaddressed deficiencies in the duct;
(e) the specific atmospheric data at the test location.
Upon Mikhail's return, I will work with him, to the extent that he is willing and|or interested, to identify, and as needed,
rectify any deficiencies relating to items (a) and (b). Wrt to item (c), if the "as-built" dimensions differ from the drawing,
then I will re-converge the model with the correct dimensions, just as I will re-converge the model for propane vapour.
Wrt item (d), these have been accounted for to the extent that I am aware of them. Finally, I will gather data for item
(e), e.g., the altitude at the test site, air pressure, temperature - even the humidity. Remember, JAC Kentfield tested,
or rather his graduate students tested various pulsejets from the University of Calgary at an altitude of over 1000 m.
To make things even more interesting, I deliberately targeted several arbitrary performance specifications, instead of
trying to "perfect" his original duct layout; this would require diameter changes, and in turn, make for a longer "re-fit".
For your reading pleasure, I have listed the arbitrary performance specifications:
(a) maximum static thrust = 5.0 kgf (that "0" is a sigificant digit);
(b) overall duct length = 850 mm (about 11 mm off the optimum);
(c) acoustic temperature = 697 K (I targeted and missed 700 K);
(d) characteristic frequency = 302 Hz (I wanted exactly 300 Hz);
And do not forget the fact that I unilaterally took diameter changes off the table.
__
You would do well to note that this model which I have constructed, and continue to improve upon, is only a reflection
of my own limited understanding of pulsed combustion, and its application in the production of thrust. It is not a piece
of shrink-wrapped software, but an inorganic extension of my mind (now that is a scary thought!). If, in the end, real
discrepancies exist between what it predicts and what is measured, then so much the better. An opportunity to learn
is more valuable to me at the end of the day. I will benefit, as will you and Mikhail. I will be pleased with any outcome!
(all of my cards are on the table, free from guesses, hack and pray, BS and TLAR; I say let the chips fall where they may)
Best regards,
Störgröße M.
__________________
"Back of the envelope calculation? Try a back, front, and inside-out of the envelope calculation. Or a napkin." -- Störgröße M.
Last edited by milisavljevic on Sat Dec 17, 2005 8:00 am, edited 4 times in total.
re: Nanosoft: New Chinese Project
I'm back. Actually I was back yesterday but I didn't have time to post. So, lets get back to business. I am going to be making a new fuel injector assembly today. Milisavljevic how far into the intake do you suppose the injectors should be.
Nanosoft
Nanosoft
-
milisavljevic
- Posts: 855
- Joined: Sat Oct 04, 2003 9:36 am
- Antipspambot question: 125
Welcome back!
Hello Mikhail!
Welcome back. I agree, let's get started! BTW, I will be posting a "new and improved" dual-intake Chinese-type pulsejet
to this thread, hopefully this evening. It will represent a first start towards next year's "Great Chinese Pulsejet Shootout"
and you are welcome to either build or adapt this layout to suit your own purposes. I have assigned the copyright to you;
think of it as a late Christmas present. Of course, any and all forum members are also welcome to try out this new design.
With respect to fuel injectors for the modified pulsejet, I strongly suggest that you rig a system that allows you to freely
move each fuel injector, across the full 110 mm length of each intake duct. I can help you size the two propane injectors,
so please let me know what sizes of tubing you have available. These pulsejets are best operated on gaseous propane,
so I recommend that you refill your fuel tank (if you have not already done so). Direct injection of liquid propane is a sure
recipe for high SFC, and not necessary for small engines; please do not waste much more time trying this fueling method.
Again, welcome back!
Best regards,
Störgröße M.
__________________
Doughboy writes, "Be civil, or be gone." To which I say, "Put up, or shut up." Oh, to hear the jackboots of our pink dictator!
Welcome back. I agree, let's get started! BTW, I will be posting a "new and improved" dual-intake Chinese-type pulsejet
to this thread, hopefully this evening. It will represent a first start towards next year's "Great Chinese Pulsejet Shootout"
and you are welcome to either build or adapt this layout to suit your own purposes. I have assigned the copyright to you;
think of it as a late Christmas present. Of course, any and all forum members are also welcome to try out this new design.
With respect to fuel injectors for the modified pulsejet, I strongly suggest that you rig a system that allows you to freely
move each fuel injector, across the full 110 mm length of each intake duct. I can help you size the two propane injectors,
so please let me know what sizes of tubing you have available. These pulsejets are best operated on gaseous propane,
so I recommend that you refill your fuel tank (if you have not already done so). Direct injection of liquid propane is a sure
recipe for high SFC, and not necessary for small engines; please do not waste much more time trying this fueling method.
Again, welcome back!
Best regards,
Störgröße M.
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