Instructables
Picture of PULSE JET ENGINES PLANS
valveless pulse jet
MINI valveless pulse jet
THIS INTRUCTABLE WILL GIVE YOU PLANS ON MAKING YOUR VERY OWN PULSE JET.
All measurements are inside diameter.

I WILL UPDATE WITH NEW PLANS EVERY NOW AND THEN.=)

I'M NOT RESPONSIBLE FOR ANY DAMAGES OR INJURY'S CAUSED BY YOU FALLOWING THESE PLANS
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lpayton27 days ago
Hi there, could you send me a copy to: lucas.payton@hotmail.co.uk
Thank you :)

Please send me a copy. I you want, send it to: www.fishboy@hotmail.se

It is very crucial that you type in those three "w"´s or else it won´t work. I appriciate if you would send me some files. Greatest regards from Sweden.

jasonyonathan2 months ago

may i have a copy.. please send it to jasonyonathan@live.com

i have one question... will it run in Indonesia (tropical climate) with LPG gas ?

whytepizza2 months ago

May i request a copy? whytepizza@gmail.com

d_dmob7 months ago

i would want a copy also. please send it to my gmail account: blessing.lad@gmail.com

d_dmob7 months ago

i would want a copy also. please send it to my gmail account: blessing.lad@gmail.com

Asuraku6 years ago
(removed by author or community request)
Sure--send me a copy. I'm the engineering teacher at a local high school and we are always looking for new plans. brian.smith@rsd.edu Thanks
here's something from some sketch-up plans i made a few years ago (the dimensions are off) worked pretty well running off of Nitrotane Race 20% (rc car gas)
pulse jet.jpg
Jonl Asuraku5 years ago
Do you still have a copy of your plans? If so I would like a copy. Thanks JonL.
would love a set if you still have them mate.
steven123654 (author)  Asuraku6 years ago
No disrespect,if you would like I could add it to my slideshow.
(removed by author or community request)
steven123654 (author)  Asuraku6 years ago
I wont post them if you don't want,I wouldn't mind having a copy tho. email:steven_durand_march@hotmail.com Thanks
cronama3 years ago
what kind of diference can you get by using a loop-tube design vs. straight tube? also what about the amount of heat generated? what kind of metal is preferd? and what about welding cooling fins on it to help disperse heat to prevent loss of structural integrity
lapdog5 cronama3 years ago
The looped tube is A valvless jet and the straight through is A valves --if u want 2 know what The valve is for as me =) FPS australia -- look up on utube =)
jocko7773 years ago
maybe im too old or too sleepy but all i see is three pictures that are too small for me to read and no list of materials or fuel requirements am i suppose to build it not knowing what materials to use ? tell me what am i missing


sourabh_me5 years ago
hi.......m a student of mechanical engineering and i have chosen valveless jet as my major project.i had seen many people doing some serious stuff with kind of those over here.actually i have a lot of plans but don't have designing procedure for any.can any one send me the designing procedure for that i have to write a full project report from that.i will be highly thankful for the kind gesture. my id is sourabh_me@yahoo.co.in
Pulse jets for a project report ,great idea
try a jam jar pulse jet engine for a start
fishhead4556 years ago
FLATULATIONS--You can build these small...you can build them large. They make a LOT of noise...but the looped-tube design you can find here http://www.aardvark.co.nz/pjet/
will give you over a hundred pounds of thrust and LOTS of noise. Ear protectors are a must even with the small ones.
Check it out.
The looped design has a serious flaw in concept, though, and that is Isaac Newton...For every action there is an equal and opposite reaction. When the jet engine draws air in from the back, it pushes the car in the opposite direction, you can thank the conservation of momentum for that. And if the engine is drawing air in from the back, it will create a force pushing the car backwards. Now, granted, the release of energy from the fuel burning being propelled backward and pushing the car forward will overcome the "backward" force, but now the jet has to overcome that force. It would be far more efficient to have the air in-take in the front of the car instead of the back. This way, the jet force and the in-take forces are added together, not subtracted.
the intake doenst create that much force? and i think the disign itself creates a better thrust because the thrust after the exposion is more than the vacoum and with the intake in front since its valveless, it leaks so even though most of the force go bakcwards, some goes fowarnd, much more than if you were to have a u design
it creates as much force as u want it to
If you build using those plan, you wont get the pulsing action. The pulsing is created by the U-Shaped. This is because when the fuel ignites the hot gases come out of the intake and the exhaust, and then gas is sucked back in through the intake and the exhaust. Because the intake is shorter, Oxygen will be sucked through the intake, but because the exhaust is longer some of the hot gases from the previous pulse is sucked back in through the exhaust, and it is this gas that ignites the fuel for the next pulse.
micnic BOOM56013 years ago
u dont need the u-shape to cause the pulsating action.As far as a pulse jet engine is concerned even a straight tube with the intake at the front and the exhaust at the back will produce pulsating action except that it may only produce minimal thrust
This explanation of the pulsing cycle of the pulse-jet engine is correct, but it has one flaw. This type of action does not require any kind of U-shape to happen. Only one chamber with a long tube and a short tube, which this design is.

This design is basically one of the U-shaped designs, unbent for ease of construction.

-Bob

Post Scriptum: See http://www.pulse-jets.com/ for a better explanation than I am able to give.
This is assuming that the pulse-jet draws in air from the front and expels it out of the back, similar to a jet engine. A pulse-jet uses cycles. It draws in air with fuel mixture, then detonates that mixture to form an explosion. The explosion moves equally out of the intake and exhaust. In a valved pulse-jet, the intake has a set of valves on it to contain this force and send it only out of the exhaust. In a valveless pulse-jet (As the U-shaped type is), there are no such valves (no moving parts at all, in fact). Instead, both the intake and the exhaust are pointed backwards to achieve a net greater thrust from the explosive exhaust cycle. While it is slightly less efficient to point the intake away form the airstream, it makes up for it's lack of intake air with a much greater thrust.

So, in summary, you light off an explosion in a can with two holes. If both holes are pointing the same direction, you get more thrust. After the explosion, both holes act as an intake (one hole has a shorter tube, allowing it to be the primary intake). Then the explosion is ignited again, and the process repeats. There is no continuous flow of air through the engine as there is in a Turbojet or a Ramjet.

Hope that cleared some things up,

-Bob
ur right, but simply using a can with two holes will only produce a few pulses because,to cause significant decrease in pressure during the intake phase u need to utilize the full momentum of the exhaust gases but using two holes simply means not all the gases expand inside the can and significant amount of the fuel burn outside

Does anybody know how to turn liquid fuel into vapor when short on space? I just might want to put a pulsejet in a donor scooter (not my current one, it has EL wire and LEDs all over it!).
Who knows if you're still interested or already found a solution, but if you haven't, what you are looking for is a heat exchanger. Can be as simple as wrapping your fuel lines around the very hot nozzle, vaporizing your fuel. Obviously this MUST be done with metal lines. This is very dangerous if done incorrectly however.
stocky supraman4 years ago
Surely that requires the engine to be running first? might be wrong but seems logical that there wouldnt be any heat otherwise...unless of course u start it with gas first.
if you coil a heat resistant fuel line or a metal fuel line a few coils around the exhaust and then into the combustion chamber, you can vaporize your liquid fuel before it is in the chamber. you will need a fuel pump to keep it flowing, and some experimenting to get the number of coiled right. most have between 4 to 6 coils.
Whats up yall, I looked this up at www.pulse-jets.com and some other places and found out if you flare out the intake/exhaust ports you will get more power. Also from what I found the exhaust should be bigger than the intake for what reason I know why. Lastly I saw that yall were talkin bout the spark plug ignition, I you leave it on after fired, It will disrupt the sequence and the engine will not preform at its best. Hope this helps, nitrocrawler95
LSharp5 years ago
Hi guys, a simple ignition system for jets is to rip the magneto out of an old lawnmower or weed whacker etc and hook it to an electric drill to spin it. Remember the ignition is only needed to start it. Once it's running you can shut off the drill. A common fuel for these is propane from a BBQ bottle. Get a needle valve to give you fine control of the fuel flow. You need to get the flow right in the "sweet spot" to get it humming!
245Tommy5 years ago
I can't get the mini engine to run, I tried fueling it from the side of the chamber and the intake from a blowtorch and a butane can, blowing air in both sides and lighting both sides.
245Tommy5 years ago
Can I run the mini engine off a blowtorch with the venturi removed?
steven123654 (author)  245Tommy5 years ago
Most likely, you would have to try.
Could you please email me a set of pans as well? I much appreciate it. shawnc5555@hotmail.com
nonickname5 years ago
Cool pulsejet.

Similar to the standard valveless lockwood pulsejet.

http://www.aardvark.co.nz/pjet/mylockwood.shtml

The main difference is that the lockwood's two jets face the same direction, which will increase thrust. Nice plans
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