Turning a Pumpkin into a Pulse Jet. Happy Halloween! This video is sponsored by PCBWay: High quality & Only 24 Hours Build Time at: www.pcbway.com/?from=rctestfl...
Chemical engineer here, also a rocket engineer. Please consider looking at pressure drop calcs and a bit of Bernoulli calculations to size the inlet and outlet. Experimental is ok, but calcs could get you there quicker.
Yes, mech engineer here. I've built a few pulse jets and the venturi is very critical. The parts had to be machined withing about a .050" tolerance to work correctly on a 2.00" dia. jet. A pumpkin isn't going to work... LOL
@@AlexJoneses Standing wave of a pipe is : speed of sound (m/s at the given temperature and gas density) / by frequency / by 4 = the length of the tube
Also, the pipe needs to be same diameter throughout, not tapered. (Only to compensate for gas density divergence due to demperature difference as the gas cools at the end length of the tube) Resonance in acoustics needs the pipe to be the same diameter throughout, actually, tapering the diameter is a method to STOP resonance.
@@AlexJoneses It seems it's not really obvious, as most who build pulsejets, even moderately successful ones, seems blissfully unaware of the theory behind it.
When it started resonating with just cardboard i got such a big smile. You made a caveman pulsejet out of a pumpkin by accident after 35 minutes of edited toiling with propane and little fans.
Future Idea: A Hot-Air Lighter-That-Air Craft (I'm team zepplin, but blimp is a c c e p t a b l e) (also hot air baloons, but those aren't that controlled) THEN Use the "dome" as a surface for flexible solar panels, for your solar plane type stuff.
@@MalKediler didn’t say it should have a pulse jet That’s a shitton of mass, is made for high speed, and is very high temp. Some modified rc quad etc props would work fine. Not certain on hot air source yet.
I built a valveless pulse jet a few years back from a set of plans. I could not get it to run until I increased the amount of fuel. I had to run my 20lb propane tank straight to it, no regulator AND I had to heat the tank in front of a heater to increase pressure with the tank pretty much full. The combustion chamber couldn't have been any bigger than those pumpkins. Food for thought.
A trombone-ey mechanism (tubes that telescope) might let you tune the length of the exhaust and find an arrangement that sustains combustion - these things are like audio resonators with extra complexity from shockwaves, heating / cooling, etc, etc.
If you give this another go, look into fuel/oxidizer injection nozzle designs for liquid rocket engines (Scott Manley has a video on this). For a pulsed-combustion engine like this you need the fuel and air to be mixed *really* well, since the combustion needs to complete in milliseconds.
As someone who loves to shove Propane into a Combustion Chamber and Set it alight, with fire and explosions everywhere (basically, I have experience making Jet engines) (Disclaimer: I haven't made a Pulse jet engine, only terrible turbofan engines) I think you should try making a pulse jet to the best of your ability (don't use a pumpkin, use something that would work more effectively) and test it from there, that way you might be able to get a better understanding of making one work without the EDF.. and hopefully, you'll be able to get it working without the EDF :D
Ahhh the V1 was a valved pulsejet. The folks who sold us our English Cocker when we lived in Libya had been in the Blitz in London in WWII. Whenever a motorcycle went by, people instinctively ducked under whatever bench they were sitting on to avoid the danged thing.
You should have tried putting the air intake and outlet along the vertical axis of the pumkin. This way the natural longitudinal lines inside could maybe have helped improve the airflow quality.
In the next episode of rctestflight: Daniel designs and builds an autonomous Santa sleigh from 3d printed parts, styrofoam, some left-over bits from earlier projects and the carcass from his Thanksgiving turkey.
most of the issue is the lack of a vacuum being pulled. - your getting terrible fuel mixtures for most of them, the blower is moving past the fuel most of the time, like a lit wick in the wind. - the moment you take off the blower however, the fuel pools and tried to fill the intake. id recommend either attempting to premix the fuel in the feed line more, after successfully pulling a vacuum, or creating a vortex to mix the fuel more richly, that way when you remove the blower after ignition, the fuel mixture when it goes lean does flame out as there is still some oxygen in the chamber as the vacuum is pulled. (Vortex mixing is a bit experimental though) Either way, your supply is currently too rich which is why it wont ignite without the blower.
Girlfriend dropping hints: Won't a nice hot cup of something pumpkin-flavored taste really nice right now? Daniel: Wait, my dear, I have just the thing for you.
Would love to see more boat/submarine content, but this was a great holiday vid! Also, once winter kicks in, putting the rover or tank on a frozen lake would be fun to see. Some kind of ice vehicle would be dope. Great job!
Hey man! Idea here, but for a valve less! I played around with valveless a little while back, but with aresol cans. The key to it without any complicated tools or literally anything is like a brake cleaner can, and some tubing. I had some half inch copper tube lying around, and as fuel I filled the bottom of the can with a mix of isopropyl alcohol 70 percent, and nitro race fuel. Prolly about a 80-90 percent nitromethane mix. At the rounded side, I made about a 3/4th inch hole. In the nozzle side I punched a hole big enough for the copper tube to fit snugly with some aluminum tape, to fill as much gap as I could. Cut the copper at roughly 6 or 7 feet, and a standard brake kleen can. Filled the can a bunch, mayne 1/4 or 3/8th, something. You light the end on the can, and the copper tube is your intake. It is completely backwards, but once you get the right fuel and copper ratio, it runs really well! Got it to run continuously at a pretty damn good speed for 30 seconds, while the can got red hot. You adjust the fuel level, the hole, and the copper length. The easiest pulse jet engine ever!!
I wonder if there is a reason the original pulse jets didn't use pumpkins. Probably out of season. Next year please try telescoping inlet and outlet pipes, moved by linear motors, pressure/sound sensors and controlled with an arduino. Then it can adjust the effective lengths to get better resonance.. Also a venturi to premix in some air, maybe its electric valves controlled by uC too. I think you're right about the vortex, but I think you want it to become an explosive mix while vortexing before it explodes not while. I mean, if you blowing into a horn, you want nice crip lip farts, not prison time ragged out slow poofy ones, to get a good tone. Maybe add a pump to add/remove water from the pumpkin to change its volume too. Add creative coding and I think your pumpkin will fly....apart.
gives up on project, finally accidentally succeeds XD My guess for why it worked: I think the rising hot air might have contributed just enough negative pressure inside the pumpkin to allow it to be self-sustaining?
Iv achieved about the same resonance with a straight peice of 150mm water pipe and a air compressor and a direct line of gas down about half way being able to move it out and in gives you the ability to tune slightly
I'm no pulse jet/jet expert but all the open cuts/holes seem to be leaking a little pressure and I'm sure in this case you want those sealed what I noticed is that the open cuts leak out the pressure causing your pulse to fail and not sustain it's combustion
The might be the flow circulation inside the pumpkin. As the faster moving air enter the pumpkin it will expand and have a higher pressure and that might not create enough small pressure so I think that if you have a bigger and longer intake then your combustion chamber then it can work. The area ratio of intake and combustion chamber might give you an amazing results. Please try to calculate geometric similarity between actual and your pumpkin experimental you can get good results.
You're even crazier than me! Pumpkin Pulse Jet ! I love it!
Thank you for the inspiration!
The world _Wants_ a jet-powered Office Chair.
But, the world *Needs* a jet-powered Pumpkin!
Awwww
👍🏼
..... You changed the orientation at the end.. add fuel and the edf quick!
"My geometries are a little more organic"
*as he rubs 2 pumpkins suggestively*
Ok
Oh
2:03 to save you a few moments
Yes ,,, I remember when he said that too...
@@itayasayag Thanks 👍
I feel sad for all the aircraft engineers who are ripping up their plans for pumpkin engines having seen this.
"Now I'm just playing with fire".
Yeah. I determined that 30 minutes ago. 🔥
Chemical engineer here, also a rocket engineer. Please consider looking at pressure drop calcs and a bit of Bernoulli calculations to size the inlet and outlet. Experimental is ok, but calcs could get you there quicker.
Right?
Yes, mech engineer here. I've built a few pulse jets and the venturi is very critical. The parts had to be machined withing about a .050" tolerance to work correctly on a 2.00" dia. jet. A pumpkin isn't going to work... LOL
Math? Pfff. Winging it is wayyyyy more fun.
What about dual injection to make up for the shit internals of the pumpkin? Lol
Next video: Autonomous pumpkin pulse jet plane :D
Soon: they start to be armed with bombs and attack London 😶
Or something like a "Ram Accelorator" but with some non-ramjet...and a pumpkin
integza had a really tough time with this, good luck!
Luckily a pumpkin doesn't tend to melt, but rather to char.
I actually thought this was an Integza video when I clocked on it. :P
@@delphicdescant wait till thay dry....
Yeah but last time I checked a pumpkin is not plastic
Best use of pumpkins that I can think of
6:17 "because... well... it's a pumpkin."
this hands-down beats any scientific thesis made in the history of ever
32 minutes of daniel being daniel
day: better
This guy should never be forced into a 9-5 desk job. The world needs tinkerers like him.
“These are significant sounds and vibrations coming through our house right now”
Pulsejets need to be tuned to a frequency, like a ported bass-speaker with resonance-chamber. (or like a church-organ pipe)
How does one calculate such frequency
@@AlexJoneses
Standing wave of a pipe is :
speed of sound (m/s at the given temperature and gas density) / by frequency / by 4 = the length of the tube
Also, the pipe needs to be same diameter throughout, not tapered. (Only to compensate for gas density divergence due to demperature difference as the gas cools at the end length of the tube)
Resonance in acoustics needs the pipe to be the same diameter throughout, actually, tapering the diameter is a method to STOP resonance.
@@grimfpv292 lmao, it's the same as tl speaker building, I'm an idiot haha, thanks for the help
@@AlexJoneses It seems it's not really obvious, as most who build pulsejets, even moderately successful ones, seems blissfully unaware of the theory behind it.
Now on thanksgiving do something with a turkey.
Resonant Turkey shooting flames out its ass!
Turduckenjet
Turkey Ramjet
Make that Turkey fly again
@@ARockyRock
🎯🔥🦃🍗
When it started resonating with just cardboard i got such a big smile. You made a caveman pulsejet out of a pumpkin by accident after 35 minutes of edited toiling with propane and little fans.
"What's that scorched spot there?"
"Oh, that's from when I built a pulse jet pumpkin"
Your neighbors must just love you ! Great job...
Turbo powered jack-o-lantern sounds very metal
Future Idea:
A Hot-Air Lighter-That-Air Craft (I'm team zepplin, but blimp is a c c e p t a b l e) (also hot air baloons, but those aren't that controlled)
THEN
Use the "dome" as a surface for flexible solar panels, for your solar plane type stuff.
A zeppelin would be hard on a small scale because it has a poor surface area to volume ratio and would need to be as light as possible.
A I R S H I P
Zepplin with a pulse jet...
seems like suicide but cooler
@@MalKediler
didn’t say it should have a pulse jet
That’s a shitton of mass, is made for high speed, and is very high temp.
Some modified rc quad etc props would work fine. Not certain on hot air source yet.
@@ericlotze7724 oh ok
roomate:complaining,
him: "woow that's preety good"
ahahah
I built a valveless pulse jet a few years back from a set of plans. I could not get it to run until I increased the amount of fuel. I had to run my 20lb propane tank straight to it, no regulator AND I had to heat the tank in front of a heater to increase pressure with the tank pretty much full. The combustion chamber couldn't have been any bigger than those pumpkins. Food for thought.
That KFM airfoil hoodie sweatshirt is RC nerd fashion at its finest.
Bro I love all of you’re videos such and inspirational person in the Rc hobby
I feel like continuously adjusting the propane input is required, once you get things started.
Very cool! Not many people on UA-cam ever attempted to build a valved pulsejet
A trombone-ey mechanism (tubes that telescope) might let you tune the length of the exhaust and find an arrangement that sustains combustion - these things are like audio resonators with extra complexity from shockwaves, heating / cooling, etc, etc.
Innnn this weeks' episode of RCTestFlights turns a pumpkin into a blast furnace...
THANK YOU! - I haven't laughed so much for YONKS!!! -
the irrationality & insanity of of such an R&D project is hilarious!!!!
If you give this another go, look into fuel/oxidizer injection nozzle designs for liquid rocket engines (Scott Manley has a video on this). For a pulsed-combustion engine like this you need the fuel and air to be mixed *really* well, since the combustion needs to complete in milliseconds.
This has got to be the most random halloween video in my feed
As someone who loves to shove Propane into a Combustion Chamber and Set it alight, with fire and explosions everywhere (basically, I have experience making Jet engines)
(Disclaimer: I haven't made a Pulse jet engine, only terrible turbofan engines)
I think you should try making a pulse jet to the best of your ability (don't use a pumpkin, use something that would work more effectively) and test it from there, that way you might be able to get a better understanding of making one work without the EDF.. and hopefully, you'll be able to get it working without the EDF :D
This channel is the best.
5:43 lmao how politely he says you are loud
I’m still waiting for a giant pumpkin to be turned into a pulse jet
the most sophisticated edf afterburner ever
I guess you haven’t seen the Tech Ingredients Hybrid jet engine yet.
ua-cam.com/video/NiKR1JamvqA/v-deo.html
Instead of a pumpkin, use a large crook-necked squash. Might be closer to the geometry you desire.
When the spooky skeletons get even scarier
Ahhh the V1 was a valved pulsejet. The folks who sold us our English Cocker when we lived in Libya had been in the Blitz in London in WWII. Whenever a motorcycle went by, people instinctively ducked under whatever bench they were sitting on to avoid the danged thing.
Best pumpkin video on the internet.
"A cardboard powered pulse jet" - what a great finale after all the tinkering proved to be not successful :p
damn daniel, back at it again with your pulse jet, man.
Many, many discoveries are serendipity derived.
Your neighbors must LOVE you... 🙄
I think you built a blast furnace
At 26:30 you can even see the metallic tape you put resonating! Very cool!
Ikr
You should have tried putting the air intake and outlet along the vertical axis of the pumkin. This way the natural longitudinal lines inside could maybe have helped improve the airflow quality.
In the next episode of rctestflight: Daniel designs and builds an autonomous Santa sleigh from 3d printed parts, styrofoam, some left-over bits from earlier projects and the carcass from his Thanksgiving turkey.
I'd love to see more pulse jet stuff.
Dang, you're easily amused. Thanks for the entertainment.
You have a great neighbor! "Have you no bounds?" LOL
most of the issue is the lack of a vacuum being pulled. - your getting terrible fuel mixtures for most of them, the blower is moving past the fuel most of the time, like a lit wick in the wind. - the moment you take off the blower however, the fuel pools and tried to fill the intake.
id recommend either attempting to premix the fuel in the feed line more, after successfully pulling a vacuum, or creating a vortex to mix the fuel more richly, that way when you remove the blower after ignition, the fuel mixture when it goes lean does flame out as there is still some oxygen in the chamber as the vacuum is pulled. (Vortex mixing is a bit experimental though)
Either way, your supply is currently too rich which is why it wont ignite without the blower.
Thank you Daniel. thank you. Happy Halloween.
Fantastic. Happy Halloween, dude. 🎃
Your channel is awesome!
There are so many amazing quotes in this video
Girlfriend dropping hints: Won't a nice hot cup of something pumpkin-flavored taste really nice right now?
Daniel: Wait, my dear, I have just the thing for you.
Hi there, also whats interesting is that the other pumpkin charded and stood up to those exhaust flames. Cool
A tribute to how much I enjoy your work I liked subbed and hit the bell a long time ago. And watched this LOL
I almost felt the heat from the video. Then I remembered that I'm currently rendering something on my laptop while watching :D
5:53 “have you no bounds?” Have you not seen his channel?
Your awesome Daniel!!
Would love to see more boat/submarine content, but this was a great holiday vid! Also, once winter kicks in, putting the rover or tank on a frozen lake would be fun to see. Some kind of ice vehicle would be dope. Great job!
I wonder if aligning the tube tangent with the inside diameter of the pumpkin would have helped with airflow geometries?
I hope this develops into a new Pumpkin Chunkin’ class someday.
I understand. I love your videos so great.
This is exactly what I need right now
Hey man! Idea here, but for a valve less! I played around with valveless a little while back, but with aresol cans. The key to it without any complicated tools or literally anything is like a brake cleaner can, and some tubing. I had some half inch copper tube lying around, and as fuel I filled the bottom of the can with a mix of isopropyl alcohol 70 percent, and nitro race fuel. Prolly about a 80-90 percent nitromethane mix. At the rounded side, I made about a 3/4th inch hole. In the nozzle side I punched a hole big enough for the copper tube to fit snugly with some aluminum tape, to fill as much gap as I could. Cut the copper at roughly 6 or 7 feet, and a standard brake kleen can. Filled the can a bunch, mayne 1/4 or 3/8th, something. You light the end on the can, and the copper tube is your intake. It is completely backwards, but once you get the right fuel and copper ratio, it runs really well! Got it to run continuously at a pretty damn good speed for 30 seconds, while the can got red hot. You adjust the fuel level, the hole, and the copper length. The easiest pulse jet engine ever!!
So we're really just flexing on integza now, maybe I should build my own lol
That's the best idea I've ever seen
I know nothing of what your doing but its interesting asf
Surprisingly, very pleasing to the ears. Jesus it sounds so good. Like a seal burping lol
That's what I call a Jack-o-Lantern!
You should identify the ideal pumpkin geometry and grow them in the desired shape.
Imagine being this guy's neighbor and hearing this in the back yard lol.
Gourd lord, what a mess :D
I see what you did there
this is more like a turbo pulse jet or a turbo ramjet than just a ramjet but its still very cool
I wonder if there is a reason the original pulse jets didn't use pumpkins. Probably out of season. Next year please try telescoping inlet and outlet pipes, moved by linear motors, pressure/sound sensors and controlled with an arduino. Then it can adjust the effective lengths to get better resonance.. Also a venturi to premix in some air, maybe its electric valves controlled by uC too. I think you're right about the vortex, but I think you want it to become an explosive mix while vortexing before it explodes not while. I mean, if you blowing into a horn, you want nice crip lip farts, not prison time ragged out slow poofy ones, to get a good tone. Maybe add a pump to add/remove water from the pumpkin to change its volume too. Add creative coding and I think your pumpkin will fly....apart.
Ha ha ha that's a different way to roast a pumpkin! Lost when you kicked it to bits at the end :) :) :)
gives up on project, finally accidentally succeeds XD
My guess for why it worked: I think the rising hot air might have contributed just enough negative pressure inside the pumpkin to allow it to be self-sustaining?
I'm a vintage Daniel follower, never dissapointed....
Very funny! Thanks! You made this Halloween! ))
Iv achieved about the same resonance with a straight peice of 150mm water pipe and a air compressor and a direct line of gas down about half way being able to move it out and in gives you the ability to tune slightly
Its like a V1 flying bomb, but with more seeds
Smells like Halloween Spirit!
A Tesla valve would probably work for the intake.
Pumpkin spice jet!
I'm no pulse jet/jet expert but all the open cuts/holes seem to be leaking a little pressure and I'm sure in this case you want those sealed what I noticed is that the open cuts leak out the pressure causing your pulse to fail and not sustain it's combustion
When they were resonating slowly, they sounded like a v-twin motorcycle
Super cool
You need to link up with colin fruze.. honestly. The internet needs this
There are definitely pulse-jet shaped gourds and im fuckin here for that....
I have not enjoyed Halloween related content more than this.
The might be the flow circulation inside the pumpkin. As the faster moving air enter the pumpkin it will expand and have a higher pressure and that might not create enough small pressure so I think that if you have a bigger and longer intake then your combustion chamber then it can work. The area ratio of intake and combustion chamber might give you an amazing results. Please try to calculate geometric similarity between actual and your pumpkin experimental you can get good results.
I feel like there is some ideal formula that was missing in favour of trial and error.
20:54 resonated with me!
Your roommate is very polite
I guess that's one way to cook a pumpkin.
thats sick
Pulse jets are always built using cultivars of Cucurbita pulsejetico.
oh yeah you're the guy with the autonomous boats... wasn't sure if it was you...
I saw this video in my Inbox and I thought it was a Colin Furze video! Haha! All kidding aside, nicely done, Daniel!