I have never heard one of these engines in person, but just the resonance that it makes in the distance sure tells me that, D**N that has got to be loud.
heh thanks, the echo is even better in person, the mic doesnt pick up the trailing end very well, as its still trying to adjust from previously recording super loud.
The cuts are not made in the direction air would be flowing, little to no air will flow through the cuts, making them almost useless for cooling. They do however keep the same aerodynamic profile, while reducing the weight dramatically, and also looking cool.
So how do the spring steel of the valves withstand the high temperature in the chamber without loosing tampering? Or the incoming air cools it sufficiently?
Thanks, I really appreciated your explanation as I had no idea how this thing works. I'm not an engineer, but I love watching this stuff (kind of like people who don't know martial arts like to watch it in the movie and appreciate it).
They are more for weight reduction while looking cool, they provide almost no cooling, if they ran lengthwise then they would provide cooling as the engine moved through the air. Methanol as a fuel source provides the most cooling, actually causing ice to form on the intake.
Yea I know a number of people in CA who have dynajets... They are loud and you should always wear ear plugs and ear muffs when doing anything loud. With all the loud noise I am exposed to I dont even use shop tools without my handy swiss 34 dB artillery gunner ear muffs.
Wow very cool. Clean looking too. I remmeber about 20 years ago or so I found an add in magazine how to build your own Pulse Jett. They would send plans how to build using an aerosol can and some thin metal. 2 different thrust versions the big one sold for $12 so my buddy and I bought that one. Weeks later in came in mail and the plans looked like a kid drew them by hand LOL. We looked it over and gave it a shot no luck. After seeing this video now there is no way we could have got it to work.
Aluminum will melt in about 3 seconds, the small ones run just about as hot. The dynajet has a power to weight ratio of about 4.5:1, weighs 1 lb produces 4.5 lbs.
Perfect video...very informative. Question: It seems that the nozzle and combustion chamber get extremely hot....can you really fly more than 2-3 minutes?
Don't let the whiners get you down. I greatly appreciated this video, finding it informative and thorough. Was fun to learn about dynajet pulse engines! Chris Shaker
Totally an aviation nut myself! Dis guy right here always watch the plane video from here with my rock playlist crancked to 11. Metallica, Delta Parole, ACDC etc. AWESOME!
It uses 120 ml fuel per minute, which isnt bad considering it can push a RC plane 275 mph. Assuming the average 2 liter car gets 25 miles per gallon, at 60 mph that equates to 150 ml per minute. Now go find out how much fuel a Bugatti Veyron uses at 260 mph.
In RC models, it appears they aren't using pressurized gas-what would recommend? It is safe to use a pressurized tank of a couple hundred lbs psi when burning fuels like gas?
I seem to remember some big rant about how a plane at 275 = 0 power, and that the plane is 500 times lighter and 500 times more aerodynamic, and that it was an unfair comparison because cars have wheel friction, and a bunch of other stuff. I looked up the veyrons MPG at top speed, it gets 2 miles per gallon at 250 mph. At 275 mph a plane with this engine would get 180 miles per gallon. 275 is low, an advanced system could potentially reach 600, where it would have ~300 mpg.
@BeckTechnologies hey i have a question... im making one of these and do harmonics matter? also where do you put fuel injector? (that is all i need to know)
Hells Teeth that is truly AWESOME ... nice explanation of an extraordinary technology. Something so staggeringly simple can produce such power! Excellent post.
This engine was actually an engine made in the 1970's. I have made many many similar engines, but you need at least a lathe and drill press to make the components.
I have a question: pressurized gas tank or no? It appears you are spraying some igniter fluid into the jet to start it, but the vacuum effect is pulling the gas from what appears to be a coke can.
Pulsejets cant really explode unless you use explosives as fuel, there isnt any way for them to build up that much pressure cause the gas goes right out the back, and no turbine wheels spinning at 100k rpm. Electrics definately have their uses and are good for park fliers, but jets definately have a speed and wow factor advantage.
A little bit, mostly they are a decorative way of reducing the weight. If you run the engine off of methanol the evaporative cooling from the methanol vaporizing will actually cause ice to form on the valve head from condensing and freezing the humidity out of the air flowing past. With gasoline or oil based fuels though the valve head will get hot enough to melt your finger prints off. For static running I suggest either alcohol or a mix to provide some cooling.
Super pulsoréacteur, it's a beautiful works, i make one like this, but with only 1,25kg of thrust and i think that the starting was difficult for my pulso. (my english is not good) Thanks for your vidéo
question, if a throttle body was hooked up to the valve system , will it regulate the amount of gas and air flowing into the chamber(quicker or slower) or will the flow always be constant?
Awesome video thank you sir!! just got me one of these to fix for a friend. its an intercontinental venture sort of thing. can't wait to fix it and kick in the gut!
Oh my word! That echo! Do you live in the Alps? :o) The info about the loud crickets made me smile. I also was amazed on how hot that exhaust became almost instantly! Thanks for sharing this video.
@BeckTechnologies Thanx For Pointing me in the right direction I was speculating! Do you have to pre-heat the fuel? Guess it depends on the fuel you want to run will this design run any fuel type?
@maydayfire i'm no extpert, and this is just a guess, but it might be that the wind of the airspeed will cool it down? i know this is partially true for conventional jets
thinking of this i think the Lennox Pulse furnace works a bit on the same principle as this engine but instead of using the pressure of escaping gas to obtain thrust this is used to push these gases through a series of heat exchangers to a point that a lot of the gases condense back to water [ the water vapor part] and out a plastic pipe the combustion chamber on sucht a furnace glows red hot when running like this engine these furnaces achieve 90 percent plus effiencency
That echo at the enda is just sooo eargasmic, i'll try to copy that sound in Fl Studio and see how it works out =P It should be my ringtone on my cell!
i was wondering about the fuel flow on this size jet ? im building a 1/4 scale model plane atm. im going to use 2 jets on it . i was going to use turbines on it ...but they cost an arm and a leg so . also whats more effective valved or valve less ?
@backcountry600 The fins do not cool the engine. If you run it statically with pure gasoline the aluminum parts can actually melt. They are for appearance and weight reduction only
@AmazingMrWonderful Well, gentlemen, this may be called Dyna-Jet, but it is originally a "Schmidt-Argus Rohr", the engine which drove the V1 (Buzz-Bomb)... actually quite efficient for its 'ancient' design.
Any higher temp resistant valve options? As you say it's a very old engine and technology has advanced considerably. Nice (ish, the crickets can't be helped though so not your fault) video :)
@BeckTechnologies They don't need to cool the engine, they just need to keep the heat of combustion away from the fuel intake to prevent auto-ignition. If you were to fill those fins in with aluminum it would indeed start to melt.
Uses about 125 ml per minute, not really all that bad for a jet engine, doesnt sound great when its just sitting around but at 300 mph you can go pretty far in a minute! :D
you put the nozzle a bit far away from the plane it self, so the exhaust does not come close to melt the plane. if you look up "plusejet planes pics" you will see what I am talking about.
what do use as a sparking device where are you puting the compresed air in the venturi is gasoline the best fuel if its too hot outside ,how long can i run the engine for on gasolin
They arent exactly cheap, and if you make them yourself they are quite a bit of work to make, after you have to make a few replacement valves you really appreciate valveless engines.
The reed valves look remarkably like those used on Evinrude and Johnson 2 stroke outboard motors from the 40's to the early 80's on the smaller capacity engines 40 hp and smaller.they are in the intake manifold right behind the carb.
In the 50s my uncle had one of these on a control-line model V1 buzz bomb. He had to whirl like a dervish to keep in under control and it was so loud it scared me, I was about nine years old.
dang. those things heat up and brighten FAST. i havent heard of these until today, but they seem like fun toys(: id like to see somebody put twin pulsejets on one of those plastic drivable electric cars that they make for kids. ahahah
Yep its definately a lot of heat, not really friction so much in the sense that it doesnt have any moving parts that are grinding against eachother or anything.
Quality video fella, and I'm totally hooked on these pulsejets. I've seen your Facebook page and your website, but can't see on them where you sell your jets... could you let me know if you still do? Many thanks.
@BeckTechnologies even if they aren't having air blown over them. using fins, WILL increase the heat transfer rate. Convection, which is based on surface area, is the only thing cooling that engine down.
I had a 3-foot lenticular aircraft with two of them on it, and you should have heard them resonate! You could hear it for miles. (Control line like to tore my shoulder out.)
I have never heard one of these engines in person, but just the resonance that it makes in the distance sure tells me that, D**N that has got to be loud.
Thanks, I was wondering how a pulse jet works, but that mosquito buzzing around made me really itchy!!!
Haha Thanks again.
heh thanks, the echo is even better in person, the mic doesnt pick up the trailing end very well, as its still trying to adjust from previously recording super loud.
I rather enjoyed the flat, smooth narration, quite informative
The short life of the valve doesn't matter if it will just get from Penemunde to London, right?
The cuts are not made in the direction air would be flowing, little to no air will flow through the cuts, making them almost useless for cooling.
They do however keep the same aerodynamic profile, while reducing the weight dramatically, and also looking cool.
Wow! That thing gets red hot in no time. Your voice lowers my heart rate :) You'd make a good professor.
Nice explanation. I remember seeing ads for these in Popular Mechanics 40 years ago. Thanks for posting.
So how do the spring steel of the valves withstand the high temperature in the chamber without loosing tampering? Or the incoming air cools it sufficiently?
Holly, that is a ton of heat and friction to get it to the point of turning smelting red.
Thanks, I really appreciated your explanation as I had no idea how this thing works. I'm not an engineer, but I love watching this stuff (kind of like people who don't know martial arts like to watch it in the movie and appreciate it).
Very nice design. It's surprising how quickly that thing turns bright red. Nice video. :)
They are more for weight reduction while looking cool, they provide almost no cooling, if they ran lengthwise then they would provide cooling as the engine moved through the air. Methanol as a fuel source provides the most cooling, actually causing ice to form on the intake.
Yea I know a number of people in CA who have dynajets... They are loud and you should always wear ear plugs and ear muffs when doing anything loud. With all the loud noise I am exposed to I dont even use shop tools without my handy swiss 34 dB artillery gunner ear muffs.
Wow very cool. Clean looking too.
I remmeber about 20 years ago or so I found an add in magazine how to build your own Pulse Jett. They would send plans how to build using an aerosol can and some thin metal. 2 different thrust versions the big one sold for $12 so my buddy and I bought that one. Weeks later in came in mail and the plans looked like a kid drew them by hand LOL. We looked it over and gave it a shot no luck. After seeing this video now there is no way we could have got it to work.
that echo in the end is sick
this is all meant to be. I feel peaceful now.
Aluminum will melt in about 3 seconds, the small ones run just about as hot. The dynajet has a power to weight ratio of about 4.5:1, weighs 1 lb produces 4.5 lbs.
Perfect video...very informative.
Question: It seems that the nozzle and combustion chamber get extremely hot....can you really fly more than 2-3 minutes?
Yep, watching the fuel still left in the fuel line get sucked into the engine looks really cool :)
Hello thanks for showing us.. just wondering do you need a fuel pump for the pulse jet ? and also can you control the thrust of it ? Thanks
4.5 lbs thrust uses about 125 ml of fuel per minute, which seems like a lot, unless you are going 300 mph.
Don't let the whiners get you down. I greatly appreciated this video, finding it informative and thorough. Was fun to learn about dynajet pulse engines!
Chris Shaker
Always wanted to know how they worked / were put together. Excellent vid!
Thirsty little blighter. Nicely made unit, thanks for the explanation, very informative. Regards from the UK.
Totally an aviation nut myself! Dis guy right here always watch the plane video from here with my rock playlist crancked to 11. Metallica, Delta Parole, ACDC etc. AWESOME!
It uses 120 ml fuel per minute, which isnt bad considering it can push a RC plane 275 mph. Assuming the average 2 liter car gets 25 miles per gallon, at 60 mph that equates to 150 ml per minute. Now go find out how much fuel a Bugatti Veyron uses at 260 mph.
In RC models, it appears they aren't using pressurized gas-what would recommend? It is safe to use a pressurized tank of a couple hundred lbs psi when burning fuels like gas?
I seem to remember some big rant about how a plane at 275 = 0 power, and that the plane is 500 times lighter and 500 times more aerodynamic, and that it was an unfair comparison because cars have wheel friction, and a bunch of other stuff.
I looked up the veyrons MPG at top speed, it gets 2 miles per gallon at 250 mph.
At 275 mph a plane with this engine would get 180 miles per gallon. 275 is low, an advanced system could potentially reach 600, where it would have ~300 mpg.
@BeckTechnologies hey i have a question... im making one of these and do harmonics matter? also where do you put fuel injector? (that is all i need to know)
Yes that is why I have focused mostly on advancing valveless engines, they are superior to valved engines in many ways.
Hells Teeth that is truly AWESOME ... nice explanation of an extraordinary technology. Something so staggeringly simple can produce such power! Excellent post.
Love hearing the reverberation in the background when you shut the engine down.
As long as you dont run hot fuels like gasoline statically for a long time it lasts forever, the valves themselves last up to about 30 minutes.
This engine was actually an engine made in the 1970's. I have made many many similar engines, but you need at least a lathe and drill press to make the components.
they made these way back. I remember late 50s having a redhead. We would start it with a bicycle pump. Yes the daisy pedal valve would not last long.
I have a question: pressurized gas tank or no? It appears you are spraying some igniter fluid into the jet to start it, but the vacuum effect is pulling the gas from what appears to be a coke can.
Pulsejets cant really explode unless you use explosives as fuel, there isnt any way for them to build up that much pressure cause the gas goes right out the back, and no turbine wheels spinning at 100k rpm. Electrics definately have their uses and are good for park fliers, but jets definately have a speed and wow factor advantage.
A little bit, mostly they are a decorative way of reducing the weight. If you run the engine off of methanol the evaporative cooling from the methanol vaporizing will actually cause ice to form on the valve head from condensing and freezing the humidity out of the air flowing past. With gasoline or oil based fuels though the valve head will get hot enough to melt your finger prints off. For static running I suggest either alcohol or a mix to provide some cooling.
Super pulsoréacteur, it's a beautiful works, i make one like this, but with only 1,25kg of thrust and i think that the starting was difficult for my pulso. (my english is not good) Thanks for your vidéo
Excellent job Beck! whats the advantage of using stainlees steel over regular mild steel? is it due to the high temparatures?thanks.
question, if a throttle body was hooked up to the valve system , will it regulate the amount of gas and air flowing into the chamber(quicker or slower) or will the flow always be constant?
Awesome video thank you sir!!
just got me one of these to fix for a friend. its an intercontinental venture sort of thing. can't wait to fix it and kick in the gut!
Oh my word! That echo! Do you live in the Alps? :o)
The info about the loud crickets made me smile. I also was amazed on how hot that exhaust became almost instantly! Thanks for sharing this video.
@BeckTechnologies Thanx For Pointing me in the right direction I was speculating! Do you have to pre-heat the fuel? Guess it depends on the fuel you want to run will this design run any fuel type?
It serves both purposes. cutting the slits reduces the mass (weight) but doubles or triples the surface area in which heat can be radiated from.
Well done. That is a clean set up. Thrust #'s?
Gave a satisfying amount of detail.
Ha I love the decay on the sound when its switched off!!! your neighbours in the next town must love you hehe
@maydayfire i'm no extpert, and this is just a guess, but it might be that the wind of the airspeed will cool it down? i know this is partially true for conventional jets
thinking of this i think the Lennox Pulse furnace works a bit on the same principle as this engine but instead of using the pressure of escaping gas to obtain thrust this is used to push these gases through a series of heat exchangers to a point that a lot of the gases condense back to water [ the water vapor part] and out a plastic pipe the combustion chamber on sucht a furnace glows red hot when running like this engine these furnaces achieve 90 percent plus effiencency
That echo at the enda is just sooo eargasmic, i'll try to copy that sound in Fl Studio and see how it works out =P
It should be my ringtone on my cell!
Where I can buy this engine?
i was wondering about the fuel flow on this size jet ? im building a 1/4 scale model plane atm. im going to use 2 jets on it . i was going to use turbines on it ...but they cost an arm and a leg so . also whats more effective valved or valve less ?
that is one beautiful pulse jet! how much did it cost you? i think im going to buy one.
Good work Beck! How does it go with Hydrogen or browns gas? hmmm.
....if your not a crappy welder the welds shouldnt split in high heat ..the metal around the weld should break before the weld itself .
Awesome mate. That thing has quite the sound to it!
@backcountry600
The fins do not cool the engine. If you run it statically with pure gasoline the aluminum parts can actually melt.
They are for appearance and weight reduction only
Be sweet to see someone make a V-1 kit to use the engine
@AmazingMrWonderful
Well, gentlemen, this may be called Dyna-Jet, but it is originally a "Schmidt-Argus Rohr", the engine which drove the V1 (Buzz-Bomb)... actually quite efficient for its 'ancient' design.
Isnt the venturi effect completely awesome? It just sucks the gasoline by itself!
Any higher temp resistant valve options?
As you say it's a very old engine and technology has advanced considerably.
Nice (ish, the crickets can't be helped though so not your fault) video :)
That's a beautiful bit of kit man, I'm so jealous!
About 4.5 lbs thrust on gasoline, 5 on methanol.
how much thrust you get? and does the tube melt if you run it too long? it was glowing yellow!
Would it be possible to hook one of these on a modified skateboard and have it push a 150 pound person?
Lol is that an Echo?! that was significantly more thrust than i expected....
yes, for starting you can use a spark plug, once it is running it doesnt need a spark.
@BeckTechnologies They don't need to cool the engine, they just need to keep the heat of combustion away from the fuel intake to prevent auto-ignition. If you were to fill those fins in with aluminum it would indeed start to melt.
Nice!! I have a folder full of plans to build these things but somehow I never did. Maybe I should give it a go. They seem like lot's of fun.
That looks soooo much nicer than the home made ones
Uses about 125 ml per minute, not really all that bad for a jet engine, doesnt sound great when its just sitting around but at 300 mph you can go pretty far in a minute! :D
@18muffinMan when its not moving through the air, its not getting any cooling, and parts can melt.
You said to test the tightness of the valves was to blow up the exhaust. You didn't say to let it cool down first and I have got bad burns on my lips.
purge98 wouldn't you test the valves tightness before it was ran?
how do you prevent the model RC plane from melting from high temps this engine produces, given that most RC planes are made of foam and wood?
you put the nozzle a bit far away from the plane it self, so the exhaust does not come close to melt the plane. if you look up "plusejet planes pics" you will see what I am talking about.
how did you do the flowejector? it have pressure to eject the fuel?
hey guy
I am having trouble finding the steel for the valve. which you used this?
what do use as a sparking device where are you puting the compresed air in the venturi is gasoline the best fuel if its too hot outside ,how long can i run the engine for on gasolin
What is that air canister thing he uses to start it? Where can I buy one???
They arent exactly cheap, and if you make them yourself they are quite a bit of work to make, after you have to make a few replacement valves you really appreciate valveless engines.
The reed valves look remarkably like those used on Evinrude and Johnson 2 stroke outboard motors from the 40's to the early 80's on the smaller capacity engines 40 hp and smaller.they are in the intake manifold right behind the carb.
Awesome breakdown and explanation. Thank you
In the 50s my uncle had one of these on a control-line model V1 buzz bomb. He had to whirl like a dervish to keep in under control and it was so loud it scared me, I was about nine years old.
One of my friends actually built a dynajet style valved engine from an old torch! (It had steel casing so it could withstand the heat)
dang. those things heat up and brighten FAST. i havent heard of these until today, but they seem like fun toys(:
id like to see somebody put twin pulsejets on one of those plastic drivable electric cars that they make for kids. ahahah
Cool echo!!! that will get the neighbors talking for miles around!
Yep its definately a lot of heat, not really friction so much in the sense that it doesnt have any moving parts that are grinding against eachother or anything.
Quality video fella, and I'm totally hooked on these pulsejets. I've seen your Facebook page and your website, but can't see on them where you sell your jets... could you let me know if you still do? Many thanks.
@pcblah Harmonics matter everything, and they're adressed in the dimensions of the motor. Build it right and it'll fire and run right.
Darn interesting. This answered my questions about the engine type. Thanks.
Will this ever get hot enough to melt straight off?
@BeckTechnologies
even if they aren't having air blown over them. using fins, WILL increase the heat transfer rate. Convection, which is based on surface area, is the only thing cooling that engine down.
Exactly, they aren't about weight, they are meant to increase surface area and subsequent cooling.
@N1H1L9 dosent that require a sound engineer? and now i have to look for dimentions... (i am making a valved version)
What level of thrust (lbs) are you producing from this model?
I had a 3-foot lenticular aircraft with two of them on it, and you should have heard them resonate! You could hear it for miles. (Control line like to tore my shoulder out.)
Nothing to apologize for - great video!!
@originxxx when the rc plane is flying the air is enouph for the pulse jet to stay cool.
wouldnt those fins also help to keep it cooler
wouldn't the fins also act like a heat sink to help keep things cool?
Used in a smoke generator that burns fog oil for the ARMY?