Please put your "I am new and need help" question here.

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metiz
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Re: Please put your "I am new and need help" question here.

Post by metiz » Sun Jan 30, 2011 12:07 am

cut the intake length down bij 80%, flare the end. I doubt that engine will run though
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TeiXalkidasSv
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Re: Please put your "I am new and need help" question here.

Post by TeiXalkidasSv » Sun Feb 13, 2011 5:23 pm

Hello everyone

I am a student of mechanical engineering and along with two of my good friends, we have to build a valveless pulsejet in order to finish our college and get our diploma.
Yes,we are newbies and that's the reason i write my question here...at the newbie topic... ;-P.
I have been doing some research about valveless pulsejets and i have to say this site and this forum has been very helpfull.
I noticed on some of the other topics, that some users wrote that they are using a programm called "Uflow" in order to see if the dimension they are using are correct or not...Can anyone please inform on where and how i can get/download this programm?It will be a great help and a great step to start with!!!

Thank you very much
SV

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Re: Please put your "I am new and need help" question here.

Post by Mike Everman » Sun Feb 13, 2011 10:15 pm

Start here: viewtopic.php?f=3&t=702&hilit=uflow+tutorial#p7881
Just the first hit on on a search of flow tutorial. There's more in a search.
Mike
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anand7
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Re: Please put your "I am new and need help" question here.

Post by anand7 » Tue Feb 15, 2011 1:19 pm

Image
Image


I have made a lockwood hiller model valveless pulsejet engine.its my first attempt and initial starting made it work okay.but when i tested again the engine is starting with a blast and then after removing the compressed air from the inlet the engine is not sustaining its operation.Instead the gas is burning through the outlet the flame is yellow in color and the engine stops working.I don't know what the effect is but i need it fixed as soon as possible.Its my dream to make it work hope someone here will help find me the problem and its solution.I have put the picture of pulsejet we made.its lockwood model used in go-karting we only had an idea of the outline

i used LPG as the fuel and a spark plug with ignition coil
tell me wats wrong and also a remedy

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Re: Please put your "I am new and need help" question here.

Post by ganuganu » Tue Feb 15, 2011 3:05 pm

just show us the video of your engine starting,so that we could help you to solve your problem..

HPSCL
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Re: Please put your "I am new and need help" question here.

Post by HPSCL » Wed Feb 16, 2011 8:46 am

anand7 wrote:I have made a lockwood hiller model valveless pulsejet engine.its my first attempt and initial starting made it work okay.but when i tested again the engine is starting with a blast and then after removing the compressed air from the inlet the engine is not sustaining its operation.Instead the gas is burning through the outlet the flame is yellow in color and the engine stops working.I don't know what the effect is but i need it fixed as soon as possible.Its my dream to make it work hope someone here will help find me the problem and its solution.I have put the picture of pulsejet we made.its lockwood model used in go-karting we only had an idea of the outline

i used LPG as the fuel and a spark plug with ignition coil
tell me wats wrong and also a remedy
With the flame being yellow in color and after removing the compressed air from the inlet, the engine is not sustaining... is an indicator that the fuel supply is too rich.

Be sure that your propane source is at a temperature of at least 70*F (21*C), as propane coming out of a cold bottle (at a high-rate of flow) will come out in a mostly liquid form. Attaching a regulator, (something as simple as THIS) between your bottle and the engine will help you to fine-tune your problem and determine if your jetting is too large.

With the regulator installed, the bottle's valve can opened fully and you can adjust your "starting" pressure to approx. 5psig - If the flame is still coming out yellow, then your jetting is too large. If not, slowly open the regulator and let your engine "warm-up" at a steady pressure of approx. 15psig. The engine should be at a low growl.

After a minute or two of "idling", slowly increase the fuel pressure to 25psig. If the engine is still burning with a blue-flame, the pressure should now be raised at a moderate level, while steadily bringing your compressed air source from about a foot away, to almost the throat of the intake. The engine should now begin to cycle (unassisted) at approx. 40psig.

Keep in mind, that a cold bottle (especially one that isn't completely full) will not flow at a steady pressure, when using only the bottle's valve as your sole regulator. These have been my findings and this is how I've troubleshooted and started all of my pulsejets, although I've never built a lockwood-hiller style pulsejet. - Can't hurt to at least try?

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Re: Please put your "I am new and need help" question here.

Post by anand7 » Wed Feb 16, 2011 1:17 pm

@HPSCL

Okay Thankyou very much I will try this and will post the results as soon as possible.
Thank you :)

HPSCL
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Re: Please put your "I am new and need help" question here.

Post by HPSCL » Wed Feb 16, 2011 4:53 pm

You're quite welcome... but please forgive the fact that I also should have mentioned that flaring the opening of your intake will help enormously. If you're not adding one as a separate piece, make sure the flare is even all the way around. I wish you Good Luck and hope to see you post, by later this evening, that your engine is running! -Sent you a PM, with an additional thought.

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Re: Please put your "I am new and need help" question here.

Post by tcoleman » Wed Feb 23, 2011 8:26 pm

To any, I'm in the middle of construction of my first pulse-jet, I believe it would be a chinese style.
The basic dimensions are 'according to Joe-Pyro' : tail pipe dia=1.368", length =20x (27.375"), CC volume=tail volume.
I want a rear facing intake. Now are the intake ratios still the same i.e. .88x-.7x for dia. and 2.67x for length?
If so that would yield an intake length of just 3.653", seem a little short. Also where allong the CC should it enter
, how far should it penetrate and does the internal end shape (other than flat) mean much.
As for what I already have, I juiced it lightly with a shot of butane, ignited it at the sparkplug hole and watched.
It burned softly for a short while, then started to sing with a rather high pitch for a shorter while.
This was followed suddenly with a loud GRONK! almost ruining a nice pair of underwear. I naturally giggled like
a little girl. I believe this was a reasonable indication that the little beast will run.
If I have done this correctly attached should be a jpg of what I have so far. All is 314 stainless .062 wall (its what I had).
Any info offered will be greatly appreciated.
Thanx, Todd Coleman
Attachments
PJ1.jpg

PyroJoe
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Re: Please put your "I am new and need help" question here.

Post by PyroJoe » Wed Feb 23, 2011 10:13 pm

Nice build,
Are you planning on using one intake or two?
What are the dimensions of the CC?

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Re: Please put your "I am new and need help" question here.

Post by tcoleman » Thu Feb 24, 2011 12:11 pm

Thanx for the comp on the build. As for intakes....yes. depends on the stock I can get my hands on.
I really think I would like one because of construction constraints. The dimensions are in the following
image this is drawn as an inside. outside dim's are bigger of course.
Attachments
PJ1_dims.jpg

PyroJoe
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Re: Please put your "I am new and need help" question here.

Post by PyroJoe » Thu Feb 24, 2011 3:35 pm

Since the chinese style intakes have the shortest intake path nearest the tailpipe, this is the dimension where the 3.65" length should be applied.
0.582+3.068=3.65"
The design should be relatively forgiving, so if you feel more comfortable with a extra 1/2" of length, give it a try, its always easier to remove length than to add on. :wink:
Attachments
chin.JPG

PyroJoe
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Re: Please put your "I am new and need help" question here.

Post by PyroJoe » Thu Feb 24, 2011 3:56 pm

One thing to remember, is to leave the short section a little long, so it can be fitted to the CC. If it is cut to 2D length it will not have enough length to interface with the CC.
Attachments
connection.JPG

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Re: Please put your "I am new and need help" question here.

Post by tcoleman » Thu Feb 24, 2011 4:59 pm

So the entry to the CC is flush with the inside. Not extending into the chamber?

PyroJoe
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Re: Please put your "I am new and need help" question here.

Post by PyroJoe » Thu Feb 24, 2011 5:00 pm

Correct

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