8 ms·

See Thru Jet Engine [video]

266 points by clouddrover 4y ago

tiahura 4y ago
Transparent carburetor in super slow motion. https://m.youtube.com/watch?v=toVfvRhWbj8 https://m.youtube.com/watch?v=toVfvRhWbj8
- PeterWhittaker 4y ago
  That was awesome! Really cut into my HN time :-)
- dylan604 4y ago
  This see thru video was much more interesting to me just because of how much more visible everything was. Sure, the slo-mo helped a lot in being a better video, but the device itself did as well. The build of the jet engine was well done, but just the visibility isn't nearly as visible into what's actually going on inside. Sure, you can see the metal casing of the combustion chamber get red hot, but it just didn't have the wow factor I was hoping for. This is not a knock on the person making the video. Sometimes you get snake eyes after all of that effort. Sometimes you roll seven, and get even better than hoped for. All in the day of the life of a content creator.
  - dorfsmay 4y ago
    Keep in mind that most recent cars (last 20 years?) Have injectors and do not use a carburetor.
    - dylan604 4y ago
      Yeah? And? So? Keep in mind now, that for the most recent CPUs are no longer 8-bit (20 years?), yet 8 bit microcontrollers are all the fad. Not really sure what your point is? We're not allowed to be fascinated with old tech that still works and has merit in demonstrating how/why it worked?
      - dorfsmay 4y ago
        Sure. I was just pointing it out for people wondering where this is on their car.
        dylan604 4y ago
        It wasn't any where near a car. It was on a garden tiller. Traditional ICE lawn equipment still uses carbs.
        garaetjjte 4y ago
        Speaking of which, I would ban these. It's ridiculous that fuel injection technology is universally used in cars for over 30 years, yet exhaust of garden equipment still stinks horribly. (oh, and also ban oil-burning two-strokes)
        dorfsmay 4y ago
        Right, in a thread about jet engines... Not sure why you're so angry‽
- rkagerer 4y ago
  Well worth the click.
- mickael-kerjean 4y ago
  This is exactly why I go on HN. I got stuck at sea so many times with no wind to get back and a broken outboard where as a reflex I was taking apart the carburator and putting it back together as a quick fix without really understanding what was going on, this is massively helpful thanks!
  - tiahura 4y ago
    Just bought a Catalina 22 two months ago and have been waiting a month for the outboard to be fixed. Glad I could help!
- sixothree 4y ago
  Not a fan of Destin knowing he works in defense and likely works on weapon systems.
MPSimmons 4y ago
I would have bet $100 this was Integza before I clicked the link.
- dymk 4y ago
  Thank god it wasn’t
subhro 4y ago
This is a very nice demonstration of turbojet. While it has not been claimed as such in the video, this is how most of the modern airplanes DO NOT work. Modern airplanes use turbofans which has an extremely high bypass ratio. In a turbofan, the turbine mostly rotates the various stages and creates very little thrust.
- gorgoiler 4y ago
  What’s the deal with high bypass turbofans vs turboprops? Turbofans look a lot like the jet engine in this video but, as you point out, only the core is the turbine and most of what’s inside the cowling is a fan for pulling air past the engine, which pulls the plane forwards. Turboprops do this but, to a lay person, in a different way. Four propeller blades instead of hundreds, and no cowling. Is it just cheaper to build a turboprop, and turbofans are the ultimate in terms of performance?
  - mlsu 4y ago
    I think turboprops are less efficient, because at high airspeeds, drag is created by vortices generated at the tips of the blades, which are exposed to the free air. By contrast, the cowling around a turbofan prevents such vortices from being created. Ducted fans are, in general, a more efficient design because of this.
    - subhro 4y ago
      Turboprops indeed fight wing tip vortices. But they also have a problem of not being able to shape air properly like Turbofans can do with stator vanes and such. As you stated, ducts are awesome.
  - subhro 4y ago
    Great question. Turbo props and turbo fans, both produce thrust, but very differently. In a turbofan, the turbine spends most of its effort turning the compressor blades. In a modern turbofan (TF) engine like GE 9x, you are looking at a 80-20 bypass ratio. This means, 80% of the air drawn from the front just flows through. Now, as the "FAN" (duh!) rotates, a huge volume of air is drawn in and compressed. As the volume moves deeper into the engine, the air pressure increases because the engine tapers down, as well as the compressor works in "compressing" the voume of air. As the air pressure increases, so does the speed and temperature. Now, as this compressed air exits from the back of the engine, it provides a forward thrust. The 20% air that DID get into the core, carrys on the combustion in the engine that provides the energy required to rotate the compressor blades. Now this is definitely simplified as there are many additional pieces, like stator vanes, equipment to shape and correct the velocity of the air, fuel injectors, igniters, afterburners (not in civilian airplanes of course) and many more contraptions. While not completely comparable, a turbo prop (TP) behaves a lot like its piston counterpart. The turbine is simply replacing a traditional 4 stroke IC engine in this case and just tasked with rotating the blades. Each of the blade is a mini (well not so mini) wing that has the shape of an airfoil. As these rotate, they generate lift but since the rotational axis is parallel to the fuselage, it is actually thrust. > Is it just cheaper to build a turboprop, and turbofans are the ultimate in terms of performance? It is definitely cheaper to build a TP. And TPs can take a lot of abuse and needs miniscule maintanance compared to TFs. But if you are talking of raw performance, turbojets (TJ) actually run (fly?) around in circles around TFs. TJs are just incredibly wasteful, inefficient and needs a lot of maintenance.
geoffeg 4y ago
Check out AgentJayZ's videos on YouTube if you'd like to learn more about jet engines in general: https://www.youtube.com/user/agentjayz https://www.youtube.com/user/agentjayz
- Azrael3000 4y ago
  TechIngredients on YT [0] also has a ongoing series about how to set up your own jet engine. [0]: https://www.youtube.com/c/TechIngredients https://www.youtube.com/c/TechIngredients
- jcims 4y ago
  One of the best channels on YouTube for understanding this kind of thing. Definitely check out the afterburner tests in his video catalog.
joelthelion 4y ago
Every time I see explanations about jet engines, I have the same basic question that never seems to get addressed. I think I know what the answer, but anyhow: why do the exhaust gases flow in the direction that we want? What prevents them from exiting from the intake?
- chewbaxxa 4y ago
  The pressure is high at the intake
  - joelthelion 4y ago
    Not outside the intake (outside the engine). Basically, to answer the question fully, you also need to say why the pressure is high there, and why it is higher than on the other side of the engine.
    - exDM69 4y ago
      Because the compressor is on the intake side of the combustion. The compressor increases the pressure more on the intake side than the resistance from the turbine does on the output side.
      - joelthelion 4y ago
        So it boils down to the angle of the blades being steeper on the compressor side than on the turbine side, doesn't it? Another related question: what happens if you don't rotate the engine before you ignite it?
        exDM69 4y ago
        There will be a fuel fire inside the engine. Just a regular fire at atmospheric pressure. But jet engines can and do backfire spectacularly at times. You can find lots of cool footage from hobby turbine engine enthusiasts on the tubes.
        deleted 4y ago
christophilus 4y ago
I just kept thinking, “Are those little screws (which don’t even look fully tightened) really going to hold that thing to the table?” Did he mention how much thrust it produced?
- sixothree 4y ago
  They look like deck screws. Probably fine.
_acco 4y ago
For a detailed animation describing how jet engines work, can’t recommend this video from Animigraffs enough: https://youtu.be/L24Wf0VlTE0 https://youtu.be/L24Wf0VlTE0

266 points by clouddrover 4y ago

Transparent carburetor in super slow motion. https://m.youtube.com/watch?v=toVfvRhWbj8 https://m.youtube.com/watch?v=toVfvRhWbj8

PeterWhittaker 4y ago
That was awesome! Really cut into my HN time :-)
dylan604 4y ago
This see thru video was much more interesting to me just because of how much more visible everything was. Sure, the slo-mo helped a lot in being a better video, but the device itself did as well. The build of the jet engine was well done, but just the visibility isn't nearly as visible into what's actually going on inside. Sure, you can see the metal casing of the combustion chamber get red hot, but it just didn't have the wow factor I was hoping for. This is not a knock on the person making the video. Sometimes you get snake eyes after all of that effort. Sometimes you roll seven, and get even better than hoped for. All in the day of the life of a content creator.
- dorfsmay 4y ago
  Keep in mind that most recent cars (last 20 years?) Have injectors and do not use a carburetor.
  - dylan604 4y ago
    Yeah? And? So? Keep in mind now, that for the most recent CPUs are no longer 8-bit (20 years?), yet 8 bit microcontrollers are all the fad. Not really sure what your point is? We're not allowed to be fascinated with old tech that still works and has merit in demonstrating how/why it worked?
    - dorfsmay 4y ago
      Sure. I was just pointing it out for people wondering where this is on their car.
      - dylan604 4y ago
        It wasn't any where near a car. It was on a garden tiller. Traditional ICE lawn equipment still uses carbs.
        garaetjjte 4y ago
        Speaking of which, I would ban these. It's ridiculous that fuel injection technology is universally used in cars for over 30 years, yet exhaust of garden equipment still stinks horribly. (oh, and also ban oil-burning two-strokes)
        dorfsmay 4y ago
        Right, in a thread about jet engines... Not sure why you're so angry‽
rkagerer 4y ago
Well worth the click.
mickael-kerjean 4y ago
This is exactly why I go on HN. I got stuck at sea so many times with no wind to get back and a broken outboard where as a reflex I was taking apart the carburator and putting it back together as a quick fix without really understanding what was going on, this is massively helpful thanks!
- tiahura 4y ago
  Just bought a Catalina 22 two months ago and have been waiting a month for the outboard to be fixed. Glad I could help!
sixothree 4y ago
Not a fan of Destin knowing he works in defense and likely works on weapon systems.

MPSimmons 4y ago

I would have bet $100 this was Integza before I clicked the link.

dymk 4y ago
Thank god it wasn’t

subhro 4y ago

This is a very nice demonstration of turbojet. While it has not been claimed as such in the video, this is how most of the modern airplanes DO NOT work. Modern airplanes use turbofans which has an extremely high bypass ratio. In a turbofan, the turbine mostly rotates the various stages and creates very little thrust.

gorgoiler 4y ago
What’s the deal with high bypass turbofans vs turboprops? Turbofans look a lot like the jet engine in this video but, as you point out, only the core is the turbine and most of what’s inside the cowling is a fan for pulling air past the engine, which pulls the plane forwards. Turboprops do this but, to a lay person, in a different way. Four propeller blades instead of hundreds, and no cowling. Is it just cheaper to build a turboprop, and turbofans are the ultimate in terms of performance?
- mlsu 4y ago
  I think turboprops are less efficient, because at high airspeeds, drag is created by vortices generated at the tips of the blades, which are exposed to the free air. By contrast, the cowling around a turbofan prevents such vortices from being created. Ducted fans are, in general, a more efficient design because of this.
  - subhro 4y ago
    Turboprops indeed fight wing tip vortices. But they also have a problem of not being able to shape air properly like Turbofans can do with stator vanes and such. As you stated, ducts are awesome.
- subhro 4y ago
  Great question. Turbo props and turbo fans, both produce thrust, but very differently. In a turbofan, the turbine spends most of its effort turning the compressor blades. In a modern turbofan (TF) engine like GE 9x, you are looking at a 80-20 bypass ratio. This means, 80% of the air drawn from the front just flows through. Now, as the "FAN" (duh!) rotates, a huge volume of air is drawn in and compressed. As the volume moves deeper into the engine, the air pressure increases because the engine tapers down, as well as the compressor works in "compressing" the voume of air. As the air pressure increases, so does the speed and temperature. Now, as this compressed air exits from the back of the engine, it provides a forward thrust. The 20% air that DID get into the core, carrys on the combustion in the engine that provides the energy required to rotate the compressor blades. Now this is definitely simplified as there are many additional pieces, like stator vanes, equipment to shape and correct the velocity of the air, fuel injectors, igniters, afterburners (not in civilian airplanes of course) and many more contraptions. While not completely comparable, a turbo prop (TP) behaves a lot like its piston counterpart. The turbine is simply replacing a traditional 4 stroke IC engine in this case and just tasked with rotating the blades. Each of the blade is a mini (well not so mini) wing that has the shape of an airfoil. As these rotate, they generate lift but since the rotational axis is parallel to the fuselage, it is actually thrust. > Is it just cheaper to build a turboprop, and turbofans are the ultimate in terms of performance? It is definitely cheaper to build a TP. And TPs can take a lot of abuse and needs miniscule maintanance compared to TFs. But if you are talking of raw performance, turbojets (TJ) actually run (fly?) around in circles around TFs. TJs are just incredibly wasteful, inefficient and needs a lot of maintenance.

geoffeg 4y ago

Check out AgentJayZ's videos on YouTube if you'd like to learn more about jet engines in general: https://www.youtube.com/user/agentjayz https://www.youtube.com/user/agentjayz

Azrael3000 4y ago
TechIngredients on YT [0] also has a ongoing series about how to set up your own jet engine. [0]: https://www.youtube.com/c/TechIngredients https://www.youtube.com/c/TechIngredients
jcims 4y ago
One of the best channels on YouTube for understanding this kind of thing. Definitely check out the afterburner tests in his video catalog.

joelthelion 4y ago

Every time I see explanations about jet engines, I have the same basic question that never seems to get addressed. I think I know what the answer, but anyhow: why do the exhaust gases flow in the direction that we want? What prevents them from exiting from the intake?

chewbaxxa 4y ago
The pressure is high at the intake
- joelthelion 4y ago
  Not outside the intake (outside the engine). Basically, to answer the question fully, you also need to say why the pressure is high there, and why it is higher than on the other side of the engine.
  - exDM69 4y ago
    Because the compressor is on the intake side of the combustion. The compressor increases the pressure more on the intake side than the resistance from the turbine does on the output side.
    - joelthelion 4y ago
      So it boils down to the angle of the blades being steeper on the compressor side than on the turbine side, doesn't it? Another related question: what happens if you don't rotate the engine before you ignite it?
      - exDM69 4y ago
        There will be a fuel fire inside the engine. Just a regular fire at atmospheric pressure. But jet engines can and do backfire spectacularly at times. You can find lots of cool footage from hobby turbine engine enthusiasts on the tubes.
      - deleted 4y ago

christophilus 4y ago

I just kept thinking, “Are those little screws (which don’t even look fully tightened) really going to hold that thing to the table?” Did he mention how much thrust it produced?

sixothree 4y ago
They look like deck screws. Probably fine.

_acco 4y ago

For a detailed animation describing how jet engines work, can’t recommend this video from Animigraffs enough: https://youtu.be/L24Wf0VlTE0 https://youtu.be/L24Wf0VlTE0