Stainless is an extremely good insulator, you can hold your hand within 3" of the engine. Add to that the fact that propane expands and acts like a refrigerant, after a minute or two of running the propane tank can actually form ice on the tank. If you sit around and do nothing for the time it takes for the tank to heat up to the point where something bad can happen, you would have to be an idiot. Common sense is keeping something for putting out fires near by, no different from a BBQ grill.
Its about 1000 degrees away from melting, you can hold your hand 6" away from the chamber just fine, the propane tank 4' away is actually chilled considerably by the evaporating propane.
If anybody wants to try this engine, it is important to switch to liquid fuel when the engine reaches operating temperature. If you operate the engine on propane vapor, thrust will decrease rapidly. You can only get 60 percent power with propane vapor. this is because the volume of the combustion chamber is not the same for propane vapor and liquid fuel. Propane vapor will take more space. Therefore, with propane vapor, the volume of the combustion chamber will be small. This information is from the Thermojet patent (US patent 3,517,510. page 4)
I would seriously consider moving the propane tank to the outside of the shed and run a longer hose. Could be a disaster being that close to the glowing part of engine.
Core temps of the pulsejet are close to the temperature limits of the fuel burning in a higher oxygen environment. Propane will produce a core gas temp of over 2600 F very easily. Propane stoves, or even torches for that matter wont really melt steel, but if you stick a steel bar in the tail pipe of a pulsejet, it will melt very rapidly and shoot globs and sparks of molten metal out of the engine.
Another interesting thing is that mild steel engines will have lower core gas temps than stainless engines. The mild steel conducts and radiates heat away so much more rapidly than stainless. A mild steel engine can give you an infra red "sun burn" up to a foot or two away, where on a cool day you can put your hand right next to a stainless engine for a few seconds without discomfort. The energy that doesnt escape from a stainless engine is kept in the exhaust to do work and create thrust.
With how good of an insulator stainless steel is, and how much propane cools when it expands out of vapor form, putting the engine directly against the propane tank would possibly just barely make up for how much the tank is cooled. A few minutes of running will cause the tank to form ice on it, 28lbs of steel + 20 lbs of propane all cooled below freezing would take a lot of heat input to not only keep up with the cooling but cause it to over pressurize.
The pressure changes rapidly, but you can measure the pressure with the right equipment, peak pressure is about 60 psi, the min pressure goes down to about 7 below atmospheric.
is it able to install on an rc jet plane? its usually the valved ones that go on them. so if you can put it on a rc plane, do you use a fuel other than propane?
Interesting. How much weight can it move? say we put one on the back of a Kid's wagon. How fast would it go? What about a common Go Kart? Also, is it smart to have your fuel tank infront of it?What it it breaks loose from it's mount and rams your Propane as it fly's off?
Its not really an overheating problem, they are designed to run that hot, using stainless to handle the prolonged high temps. You can run them on RC planes, liquid fuel systems with pumps work the best.
Butane does not burn very quickly but you should still be able to get an engine going on it. You need an ignition source in the combustion chamber for best effect, if it doesnt ignite in the right spot it wont build up to the explosion like combustion.
Nope, the strength of the metal is more than enough to contain the pressure. The way pulsejets work, part of the cycle they are below atmospheric pressure, if the metal becomes hot enough to be damaged it will squish flat rather than explode out, the force to crush a tube is many many times less than the force to burst it.
Is it just trial and error in building these engines or you have to know and apply different formulas in sizing and dimensions? Also can this particular model be run on liquid fuel? Thanks
i dont know much about the abilities of mixing gases but there seems to be an argument over using methanol or kerosine. is it possible or has anyone tried mixing the 2 to creating a different type of burning process? more of a curious question.
I would think that the header tape would probably cause the stainless to melt as it would prevent a lot of heat from excaping. Ceramic lining a pulsejet on the other hand would keep the stainless from absorbing a lot of heat in the first place. Doing both could have some very interesting results.
would an engine of this size even be capable of running on a model aircraft using propane? (the small propane or MAPP brazing cylinders come to mind) or would that not produce enough fuel for any significant amount of flight time? also, whats the rough diameter of that combustion chamber? 6in? more? is the 10lb of thrust a figure only attainable under ideal "bench-test" configurations, or could u actually get that on a flying model? thanks!
a chamber (combustion chamber) gets filled with gas, (the end bit thats fat on this video) then a spark plug ignites it all and the gas creates a big bust of air (also can be provided by air compresser) that pushes a continuous flame out the flame tube. the spark plug doesnt have to be sparking at a constant cus the flame from the first fire keeps it going. and the gas has to be flowing at a continues flow. any more questions about em?
So how many Lbs the contraption weights with a spark plug configuration? How big of a battery for the ignition? How long can it run continuous at 1%,10%,50%,100%? What is the time from spark ignition to 100% throttle? Did you notice any attitude changes in the operation of the engine in different meteorological conditions? I am a nerd, I think i want to built one of those.
Wrap it in some Kaowool/Inswool, ceramic wool that can stand up to 2800-3000 degrees F. Great insulator and will probably enhance efficiency as more energy is directed out of the exhaust and not radiated off as heat. I use it in my propane forge, 2" thick, and the steel shell only gets up to a few hundred degrees despite the inside behind bright yellow orange.
Hy, I plan to build such an engine myself-valveless...and I had a few ideas of how to improve it!What's do you think about: 1. A ceramic (or asbestos?) coating inside the combustion chamber. It would protect the outer metal shell and it would increase the combustion temperature thus increasing the fuel efficiency and power? 2. A turbo, powered by some exhaust that would in turn send compressed air into the intake? 3. Linking 2 eng. in a series? exhaust to intake. Thanx, Alex C
@BeckTechnologies 1. Put it in a plane to demo it. (ie fly it) 2.Show how you propose to carry liquid Propane in the plane (and control flow rate) 3. Show the engine on a test rig doing 1lb up to 10lbs thrust. 4..Demonstrate thust to weight ratio.
mild will do, but it will deteriorate after a while. i built a small one with .060 thick mild steel and only ran it 7 times before it burned up. im trying to come up with a design that uses standard plumming parts so more people can make them.
Dimensions are rather important, cant just stick a bunch of tubes together and expect it to do anything other than burn fuel and make noise if it runs at all. With some engines altering the dimensions 1/8" can result in a 50% increase or decrease in thrust.
@EnglishTurbines That particular video was running on a nearly empty, cold tank, so it was not at max throttle. At max throttle it is much more like the videos of the 4lb thrust engine, with distinctive shock wave pattern in the exhaust. The engine will put out approx 14 lbs on liquid fuel like methanol, you dont fly with propane. Propane is simply a clean easy no mess no fuss fuel for ground tests and demos. You dont go home smelling like kerosene at the end of the day.
could you guess how much is the speed of the wind exiting the exhaust? I'm working on a project and I need to know the proximate wind speed generated by almost this size of engine :)
That's 10lb thrust. A lot of people use propane. It can be as cheap as the cost of scrap metal and some brake lines if you know how to weld. Now sure you could rig it on a bike, gokart or whatever, but I'd be iffy about ridding along with a red hot piece of steel. Plus you can't run them very long without running the risk of failure.
Is there a way to measure pressure within the combustion chamber ? I know it's oscilating between positive and negative pressure... but how great is the pos pressure ?
TrueBlogge777, the V-2 ballistic missiles were powered by liquid fueled rocket engines, not jet engines like the V-1 cruise missiles. Perhaps you were confused by the fuel pumps used in the V-2s.
wolfe1970, not everything is intended for use on a model. check out the 700lb thrust pulse jet video, do you think that guy wanted to strap it to a model?
@Themayseffect Pulsejets will run on almost anything that burns, but if you deal with them on a daily basis, you'd probably go with propane too, since you dont come home every night stinking of kerosene. Methanol mixed with hydrocarbon fuels produce very good results. Hydrocarbons will burn significantly cleaner with methanol mixed in.
Pulse jet engines are pretty easy, you ignite the fuel, and a "pulse" is created. The resulting vacuum pulls more fuel into the combustion chamber, and it ignites again. This process repeats and creates a jet engine.
Unfortunately you cant just buy parts for pulsejets, we make all the parts from flat sheet metal and roll them and weld them up. We also offer partially completed engine kits with all the materials you need, and most parts rough cut / formed
Is it possible to make this in a bigger scale say maybe 2-3 times bigger. I have donloaded your prints an all im just wondering if it wont be any problem? maybe use thicker steel? is liquid fuel ok?
Help! built myself a ThermoJet he does not suck the air gotta keep compressed air blowing in dult input when he cut off the air conprimido I detail what I'm using butane gas (coal gas will cusine q of the gas may be some tips there guys
@EnglishTurbines The evaporative cooling from methanol results in a much higher fuel charge density, combined with its rapid burn speed, result in much more thrust output.
Stainless steel has one of the highest insulating values of any high temp metal. It gets hot but the amount of heat that it radiates away is suprisingly low. If it were a steady combustor turbulence could be bad, but the pulsating combustion is actually greatly enhanced by the right kind of turbulence. The more turbulence the faster the fuel and air mix, and the pulse of combustion will be faster and more powerful. The turbulence also allows the engine to self start.
Stainless is an extremely good insulator, you can hold your hand within 3" of the engine. Add to that the fact that propane expands and acts like a refrigerant, after a minute or two of running the propane tank can actually form ice on the tank. If you sit around and do nothing for the time it takes for the tank to heat up to the point where something bad can happen, you would have to be an idiot. Common sense is keeping something for putting out fires near by, no different from a BBQ grill.
Its about 1000 degrees away from melting, you can hold your hand 6" away from the chamber just fine, the propane tank 4' away is actually chilled considerably by the evaporating propane.
If anybody wants to try this engine, it is important to switch to liquid fuel when the engine reaches operating temperature. If you operate the engine on propane vapor, thrust will decrease rapidly. You can only get 60 percent power with propane vapor. this is because the volume of the combustion chamber is not the same for propane vapor and liquid fuel. Propane vapor will take more space. Therefore, with propane vapor, the volume of the combustion chamber will be small. This information is from the Thermojet patent (US patent 3,517,510. page 4)
Andrew Shingange switch to another fuel lin3
I would seriously consider moving the propane tank to the outside of the shed and run a longer hose. Could be a disaster being that close to the glowing part of engine.
nice lamp
That shot looking down into the chamber was just awesome.
can u send me a blueprint of ur engine plz. i m making a smaller version for a project
Core temps of the pulsejet are close to the temperature limits of the fuel burning in a higher oxygen environment. Propane will produce a core gas temp of over 2600 F very easily. Propane stoves, or even torches for that matter wont really melt steel, but if you stick a steel bar in the tail pipe of a pulsejet, it will melt very rapidly and shoot globs and sparks of molten metal out of the engine.
interesting for an R/C setup but how much thrust does it produce and would the extreme heat be a problem?
Another interesting thing is that mild steel engines will have lower core gas temps than stainless engines. The mild steel conducts and radiates heat away so much more rapidly than stainless. A mild steel engine can give you an infra red "sun burn" up to a foot or two away, where on a cool day you can put your hand right next to a stainless engine for a few seconds without discomfort. The energy that doesnt escape from a stainless engine is kept in the exhaust to do work and create thrust.
With how good of an insulator stainless steel is, and how much propane cools when it expands out of vapor form, putting the engine directly against the propane tank would possibly just barely make up for how much the tank is cooled.
A few minutes of running will cause the tank to form ice on it, 28lbs of steel + 20 lbs of propane all cooled below freezing would take a lot of heat input to not only keep up with the cooling but cause it to over pressurize.
The pressure changes rapidly, but you can measure the pressure with the right equipment, peak pressure is about 60 psi, the min pressure goes down to about 7 below atmospheric.
is it able to install on an rc jet plane? its usually the valved ones that go on them.
so if you can put it on a rc plane, do you use a fuel other than propane?
Pulse jets have been known to run on anything from sawdust, coal dust, to diesel and petrol.
I was wondering that what's the radius of the chamber's back-panel?
Interesting. How much weight can it move? say we put one on the back of a Kid's wagon. How fast would it go? What about a common Go Kart?
Also, is it smart to have your fuel tank infront of it?What it it breaks loose from it's mount and rams your Propane as it fly's off?
@BeckTechnologies oh okay. Cool man. Hey how much thrust do you think it's putting out?
@BeckTechnologies makes sense. but how big is the power increase compared to methanol or kerosene?
Its not really an overheating problem, they are designed to run that hot, using stainless to handle the prolonged high temps. You can run them on RC planes, liquid fuel systems with pumps work the best.
Is there any compression of air before it enters the combustion chamber pulsejets?
if so how is it compressed ?
Butane does not burn very quickly but you should still be able to get an engine going on it. You need an ignition source in the combustion chamber for best effect, if it doesnt ignite in the right spot it wont build up to the explosion like combustion.
Nope, the strength of the metal is more than enough to contain the pressure. The way pulsejets work, part of the cycle they are below atmospheric pressure, if the metal becomes hot enough to be damaged it will squish flat rather than explode out, the force to crush a tube is many many times less than the force to burst it.
Is it just trial and error in building these engines or you have to know and apply different formulas in sizing and dimensions?
Also can this particular model be run on liquid fuel?
Thanks
how much thrust is that thing kickin out and how many would i need for a jet pack
i dont know much about the abilities of mixing gases but there seems to be an argument over using methanol or kerosine. is it possible or has anyone tried mixing the 2 to creating a different type of burning process? more of a curious question.
does the construction have to be stainless steel? or will mild steel do?
I would think that the header tape would probably cause the stainless to melt as it would prevent a lot of heat from excaping. Ceramic lining a pulsejet on the other hand would keep the stainless from absorbing a lot of heat in the first place. Doing both could have some very interesting results.
0:42 I expected a mini boom, and got that cute PFT sound :D
would an engine of this size even be capable of running on a model aircraft using propane? (the small propane or MAPP brazing cylinders come to mind) or would that not produce enough fuel for any significant amount of flight time?
also, whats the rough diameter of that combustion chamber? 6in? more?
is the 10lb of thrust a figure only attainable under ideal "bench-test" configurations, or could u actually get that on a flying model?
thanks!
jeez it got hot did u try to measure the temperature with temp gun ??? bet l=its like 1000F
a chamber (combustion chamber) gets filled with gas, (the end bit thats fat on this video) then a spark plug ignites it all and the gas creates a big bust of air (also can be provided by air compresser) that pushes a continuous flame out the flame tube. the spark plug doesnt have to be sparking at a constant cus the flame from the first fire keeps it going. and the gas has to be flowing at a continues flow. any more questions about em?
So how many Lbs the contraption weights with a spark plug configuration?
How big of a battery for the ignition?
How long can it run continuous at 1%,10%,50%,100%?
What is the time from spark ignition to 100% throttle?
Did you notice any attitude changes in the operation of the engine in different meteorological conditions?
I am a nerd, I think i want to built one of those.
same
Wrap it in some Kaowool/Inswool, ceramic wool that can stand up to 2800-3000 degrees F. Great insulator and will probably enhance efficiency as more energy is directed out of the exhaust and not radiated off as heat. I use it in my propane forge, 2" thick, and the steel shell only gets up to a few hundred degrees despite the inside behind bright yellow orange.
Hy,
I plan to build such an engine myself-valveless...and I had a few ideas of how to improve it!What's do you think about:
1. A ceramic (or asbestos?) coating inside the combustion chamber. It would protect the outer metal shell and it would increase the combustion temperature thus increasing the fuel efficiency and power?
2. A turbo, powered by some exhaust that would in turn send compressed air into the intake?
3. Linking 2 eng. in a series? exhaust to intake.
Thanx, Alex C
what size is the diameter of the tie pipe and combustion chamber and how long is the tail pipe
How much would it cost for a thermo jet a little maller than thisone. Say 6-8lb thrust with the gas intake nozzzles as well?
Well Done, where could I get some dimentions for one of these? Do you sacrifice mutch thrust using valveless?
That is true. Once it gets hot, the cycle continues on it's own.
What are the uses for these engines that you sell?
@BeckTechnologies Why don't you make a video showing the performance difference of the same engine with different fuels?
It breathes air? and if so, where is the intake?
i was waiting for the spark, propane tank & boooooommmmm, seriously though how would you fit that in a model with out it catching on fire
10 lbs thrust, with a special mix of methanol and gasoline and a model turbine fuel pump One of these has put out around 14 lbs thrust on a RC setup.
Howd u connect the propane to the engien wo a regulator, adaptor wise
Would it be able to run without the sparkplug when glowing red hot (Dieseling effect)?
could you use a soup can as the chamber?
"MOVE THE BLOODY PROPANE TANKS!!~"
Haha, I was thinking the same thing.
Ikr. It’s terrifyingly close.
times even the air trying to put into rotation? should bring more power
@BeckTechnologies 1. Put it in a plane to demo it. (ie fly it)
2.Show how you propose to carry liquid Propane in the plane (and control flow rate)
3. Show the engine on a test rig doing 1lb up to 10lbs thrust.
4..Demonstrate thust to weight ratio.
what about running this off of and in conjunction with woodgas
@BeckTechnologies Do you have clip of one of your engines running on Methanol perhaps?
What type of spark plug is required?
mild will do, but it will deteriorate after a while. i built a small one with .060 thick mild steel and only ran it 7 times before it burned up. im trying to come up with a design that uses standard plumming parts so more people can make them.
Does the small 4lb thermojet start by itself as well?
Dimensions are rather important, cant just stick a bunch of tubes together and expect it to do anything other than burn fuel and make noise if it runs at all. With some engines altering the dimensions 1/8" can result in a 50% increase or decrease in thrust.
Segurança NOTA 10 pra esse cara pqp...
This guy think Safety certainly ò.Ó
Is it 10lbs of thrust or does the engine weigh 10 lbs?
@EnglishTurbines
That particular video was running on a nearly empty, cold tank, so it was not at max throttle. At max throttle it is much more like the videos of the 4lb thrust engine, with distinctive shock wave pattern in the exhaust. The engine will put out approx 14 lbs on liquid fuel like methanol, you dont fly with propane. Propane is simply a clean easy no mess no fuss fuel for ground tests and demos. You dont go home smelling like kerosene at the end of the day.
after the engine got started & the combustion chamber glows, did you cut your ignition spark's power off or did you just keep the ignition spark on??
u turn it off the how exhaust gases get pulled back and reignight the fuel because of a vacum in the engine
Are there any good videos that explain how these work?
could you guess how much is the speed of the wind exiting the exhaust? I'm working on a project and I need to know the proximate wind speed generated by almost this size of engine :)
That's 10lb thrust. A lot of people use propane. It can be as cheap as the cost of scrap metal and some brake lines if you know how to weld. Now sure you could rig it on a bike, gokart or whatever, but I'd be iffy about ridding along with a red hot piece of steel. Plus you can't run them very long without running the risk of failure.
Is it a possibility that your combustion chamber could explode with more throttle?
Which type of valveless pulse has the most thrust when made right?
how would you trasmit this to movement
Is there a way to measure pressure within the combustion chamber ? I know it's oscilating between positive and negative pressure... but how great is the pos pressure ?
But will it blend?
Just out of curiosity, have you ever tried to measure its loudness with a sound level meter?
How much thrust ?
0))
TrueBlogge777, the V-2 ballistic missiles were powered by liquid fueled rocket engines, not jet engines like the V-1 cruise missiles. Perhaps you were confused by the fuel pumps used in the V-2s.
yeah v 1's used a pulse jet while v2's used a c-stof and t-stof rocket
@BeckTechnologies yea that i know. so what about nitromethane and alcohol. ive never seen those fuels used in turbines or pulsejets/dynajets
wolfe1970, not everything is intended for use on a model. check out the 700lb thrust pulse jet video, do you think that guy wanted to strap it to a model?
How long can it run before it melts down?
I'd love to build one to fly here at my club. it would drive the old guys crazy. hehe
@Themayseffect Pulsejets will run on almost anything that burns, but if you deal with them on a daily basis, you'd probably go with propane too, since you dont come home every night stinking of kerosene. Methanol mixed with hydrocarbon fuels produce very good results. Hydrocarbons will burn significantly cleaner with methanol mixed in.
Where is the fuel line going in to the engine at
thats an engine or a lightbulb??
Please, can you help us about Pulse-jet Ignition System ?
Pulse jet engines are pretty easy, you ignite the fuel, and a "pulse" is created. The resulting vacuum pulls more fuel into the combustion chamber, and it ignites again. This process repeats and creates a jet engine.
if you take away the sparker engine works?
Yes
How much thrust do you think this puts out?
How did you make it valveless? I always thought pulse jets of that style need a valve. I've always seen valveless in a J shape.
how its looks like from inside?
Question did you leave the sparkplug on
how much does it weigh
so 14 lbs of thrust is enough to fly a model airplane?
Is this available for sale?
Say I want to annoy the neighbours, how much dB does this (roughly) produce?
how much trust can you get ?
Unfortunately you cant just buy parts for pulsejets, we make all the parts from flat sheet metal and roll them and weld them up.
We also offer partially completed engine kits with all the materials you need, and most parts rough cut / formed
@BeckTechnologies Methanol eh?..but Methanol has such a low calorific value, certainly lower than Kerosine for instance?
I think there's a small hole in the chamber at the back.
@ 1:22 how come the camera isn't melting
Are you still selling these?
Is it possible to make this in a bigger scale say maybe 2-3 times bigger. I have donloaded your prints an all im just wondering if it wont be any problem? maybe use thicker steel? is liquid fuel ok?
Help! built myself a ThermoJet he does not suck the air gotta keep compressed air blowing in dult input when he cut off the air conprimido I detail what I'm using butane gas (coal gas will cusine q of the gas may be some tips there guys
Can it power a bicycle after you gained some speed by paddling
Olivier Beucken two twenty pound pulse jets will pass cars on the highway
real life bart Simpson so four of these will get me highway speeds?
Olivier Beucken If you run it on the right fuel it will only take three and it will pass cars on the highway
Thanks :) Nice to see you on here too :)
@EnglishTurbines
The evaporative cooling from methanol results in a much higher fuel charge density, combined with its rapid burn speed, result in much more thrust output.
Hello, I would like to ask a question
Stainless steel has one of the highest insulating values of any high temp metal. It gets hot but the amount of heat that it radiates away is suprisingly low.
If it were a steady combustor turbulence could be bad, but the pulsating combustion is actually greatly enhanced by the right kind of turbulence. The more turbulence the faster the fuel and air mix, and the pulse of combustion will be faster and more powerful. The turbulence also allows the engine to self start.