You are a hazard to humanity, attempting to gloss over life threatening engineering flaws as you you, and rude besides. Not to mention, you seem to make a point of parading your ignorance. Please do everbody a favor and test Darwin's Jet yourself according to your pet theories, whether or not you feel qualified.
ducted fans lack a compression stage if I'm not mistaken, and the thrust they produce is no greater than that of a propellor?
The thrust that this so-called electric jet produces is no greater than the particular form of propeller that is called a "ducted fan". So no, you are not mistaken in that exact observation but you went on to draw the wrong conclusion nonetheless.
To tell the truth, I am awed at how well aeronautical fraud actually works. It has never been in short supply, ever since the days of Icarus. The most remarkable form of aeronautical fraud is the kind that perps talk themselves into believing, and we can just hope that they don't take out too many innocent bystanders.
"The electric jet engines work like turbofan jet engines in a regular passenger jet. They suck in air, compress it and push it out the back.
But wait, that is exactly what a ducted fan does. Well, playing a bit fast and loose with the terminology, aren't they? A minimal amount of compression goes on, while the relevant effect is actually acceleration of a mass of air. The higher velocity air requires less cross-sectional area to transport equivalent volume (the volume that is swept by the cross sectional profile of the ducted fan as it moves through space) and so, the throat of the ducted fan is narrower than the intake, somewhat like a turbofan but for different reasons. The purpose of compression is to heat the air, to prepare it for the combustion reaction. The electric ducted fan has no such purpose for compressing air.
However, the compressor fan in the front is not turned by a gas turbine, but by a high performance electric motor.
A jet engine is a combustion engine. No combustion, no jet engine.
Therefore, they run much quieter and completely emission-free...
And in this altered reality, they are much more efficient at creating marketing spin than boring old electric motors.
The plane in the video is not flying with max forward speed...
And why not? Presumably because it can't.
It is hovering, hence the jets point a bit downward...
"A bit"... come on, that is not "a bit".
Get over it.
You get over it, you are the one with the shitpost trigger finger.
Btw. they have several videos, perhaps you warched the wrong one.
I watched several videos, including the 1/5th scale model video, which is the most informative because it shows the most forward flight. When flying forward at maximum speed, it is clear that the flight characteristics are 1) very inefficient 2) not primarily the characteristics of an aeroplane, but more akin to a quadcopter. This has two implications: 1) the touted aerodynamic efficiency due to the wings is not going to happen 2) the safety factor of being able to glide to a landing is not going to happen.
There you have it. However much you rant about it, this flying machine remains a close relative of the flying brick.
In that case, would the lift from the airframe moving forward would be much more than an equivalent helicopter and thus the range would be much better?
... This issue could be somewhat fixed by changing the forward ducted fan assembly into a real canard as in the concept animation, but with all the junk attached it would be a contender for world's least efficient canard wing, and fragile to boot.
Just add plain airfoil canards on the outer ends of the forward nacelles and you will have an aircraft with fully functional canards.
Just add plain airfoil canards on the outer ends of the forward nacelles and you will have an aircraft with fully functional canards.
But that is not what was demonstrated, and it will still fly like a brick without hugely increased foil area, including the rear foil. Do not underestimate the disruptive effect on lift of the turbulence around the motor housings. By the time the foils are large enough to glide safely or even significantly increase endurance, this design is back to being just a VTOL canard plane, not remotely in the ballpark of a flying car. Clearly the promoters are trying to pull one over on the public: this thing is really just an electric quadcopter with ducted fans, it will never be an airplane or a flying car.
Obviously while it is more or less hovering the jets are pointing in an angle downwards. When it is flying with full speed the jets will be more or less horizontal...
Dead wrong. Those motors will never be horizontal in straight and level flight, no matter how fast the thing goes. There is no front wing for crying out loud. What do you think will keep the front end up, wishes? And the back wing is just a stick. Look at the video closely. Even at maximum forward speed, the fans are still angled down at roughly 40 degrees. Seems, you really want to believe in this. Well I have a suggestion: volunteer to go for a ride, since you think it is safe. Maybe the power won't run out, no motors will overheat, no fuse will blow, no wires will vibrate loose, and you will be fine.
And they aren't jets. And you likely do not have the slightest clue what wing loading is. Feh.
There are also graphics showing the engines pointed straight back.
Wishful thinking. Try that in the air and it will plummet like a rock.
Modding -1 "disagree" will not make that thing any more airworthy. Lose power and it will nosedive spectacularly, ending in a mangled heap of plastic and meat.
aren't you supposed to spout this kind of: "Man will never fly!" garbage _before_ it's been clearly demonstrated. The video shows it taking off and in forward flight
To call that demonstration "forward flight" you need to be charitable or gullible. Look again. The front motors are pointed straight down. That does not qualify this thing as an airplane at all, it qualifies it as some kind of helicopter. Helicopters also can fly forward, but they are not airplanes, and they suck for fuel efficiency. Like this thing, which claims to be fuel efficient because of its wings, but don't be stupid. Look at it, it doesn't even have wings on the front and the back wing is little more than a spoiler.
You can see what is going on more clearly in this video of their 1/5th scale model (i.e., 1/125 weight) where the motors are always angled down at least 40 degrees, otherwise it will fall out of the sky. If it had proper wings the motors would point straight back. All that downward vectoring comes straight out of the battery life, which is the main selling point of this concept. Well, if you are a snake oil collector then feel free to buy this concept.
Some wise person said "an open mind is a fine thing, but let it not be gaping".
Haha, that's funny. This thing will never transition for forward flight, except as a forward hover. It doesn't even have a forward wing for crying out load and the rear wing loading is absurd, not to mention the profile drag. But thanks for doing your part to provide an in-the-wild demonstration of the credulous thing.
Well, Red Hat is buying into a lot of crap that is only marginally Linux, and is far from what you could call obviously reliable. Like Openstack, Ceph, Gluster, that kind of thing. When you build your house high enough on a foundation of shit, it eventually sinks into it. Like, Openstack actually depends on MySQL for distributed consistency, how far do you think that frisbee will fly?
aren't you comparing this vehicle to a plane when perhaps it should be compared to a helicopter?
It a fuselage optimized for forward flight and it has wings. Therefore it is trying to appear to the view as a plane. It is really a helicopter, as you say, and as I implied by calling the show a "hover demo".
In that case, would the lift from the airframe moving forward would be much more than an equivalent helicopter and thus the range would be much better?
No, for several reasons. The lift from the the slippery egg shape will be roughly zero except at stupidly high angles of attack and stupidly high speeds, so forget that. The lift from the main, rear wing will be pathetic because of the massive disruption of flow causes by the ducted fan housings. And the wing loading is way too high anyway. The video optimistically implies some kind of laminar flow over the wing and through the fans, but the there is so much structural junk in that way that I will have to call that pure fantasy. That rear wing assembly has airfoil efficiency roughly equivelent to a backyard barbeque.
And that is not the worst problem. Aerodynamically, the worst (of many) problems with this concept design is, the forward canard will generate exactly zero lift. All the lift at the front comes from the vertical thrusters, which will need to stay running (at high speed and power consumption no doubt) the entire time that the plane attempts to maintain efficient horizontal flight. This issue could be somewhat fixed by changing the forward ducted fan assembly into a real canard as in the concept animation, but with all the junk attached it would be a contender for world's least efficient canard wing, and fragile to boot.
Obviously, unpowered gliding is a complete non-starter with this configuration. At best, some inefficient form of foil-assisted forward flight will be possible, most likely not efficient enough to justify the additional weight and wetted surface of the real airfoil.
if the engines die you can't "glide" it back to a landing. However the massive redundancy (36 fans) would prevent that from being the point of failure (but the battery, power electronics might be)
You might want to upgrade that "might" to a "will". Consider the case of flying over water with unexpected headwind that lengthens the trip past the battery endurance, or countless other scenarios that come up regularly in real life.
That's where the parachutes come in I guess.
I suggest, some healthy skepticism will come in even more handy in terms of minimizing loss of life.
Since I'd rather have a (safe, easy to fly) helicopter than a plane, I think I'd buy this to go (short) island hopping in the South Pacific.:)
You're a great straight man, you know that? Exactly the scenario I mentioned above...
If you plastered it with solar cells, how long would do you think it take to charge?
This demo is just a hover demo, the wings are actually just pure decoration for promo purposes. Not to say that a hover demo is an easy feat, but the cool looking slippery fuselage is not doing anything useful in an aerodynamic sense, rather it is purely for social engineering at this point. Doubt me? Look at the canard, it is not even an airfoil by any stretch of the imagination. This aircraft is absolutely incapable of gliding, it would immediately dive straight down if you tried to do so, with spectacular results.
Given that this is just a hover egg, maybe optimize it for that? The concept render actually shows an airframe that could be capable of some kind of glide ratio, but from the look of it, only at really high speed. Trying to flare out for a standard runway landing would most likely be a life threatening experience. With all those ducted fans, the profile drag will be through the roof. Glide ratio, maybe 5 to 1, optimistically, unless the profile drag can be reduced by some as-yet uninvented magic. By comparison, a garden variety Cessna gets 9:1, which means that landing without power already requires some skill. With 5 to 1, you basically need to be a Chuck Yeager to walk away from it.
Might as well just be honest about it and lose the wings entirely. Simple sticks will do, like the canard, and save some weight. Then what is the remaining reason for having such small fans? Small fans are less efficient than larger ones, meaning the batteries will run out considerably faster than some more practical design.
Or move there. The difference is starting to move into the embarrassing zone. Check your kevlar vest at the border, and oh, if you forgot to buy your travel medical it won't cost you $30k to get back home if you happen to break your leg running away from a moose.
Frankly, I find the quality and content of TED talks embarrassing. Hmm, why should I feel embarrassed about that? I don't know, but I do. So often verging on intellectual fraud. A venue for self-promotion and mutual intellectual masturbation. Well, I guess it keeps them off the street.
If you do not care about unibody design then feel free to drive one of those old cars that had frames and tended to kill you more. And if you can't see how that relates to handset design then just don't worry, be happy.
thanks to a couple of decades of convergent evolution, there is often a reasonably sane quasi-default layout.
Actually, the default for DVR is insane. There is no good reason to have a stop button right next to play/pause when you almost never want that. Just lose the stop button. I mean, what does it do that pause, eject and power don't already cover? Or at least, place it well away from the useful buttons.
Slashdot Mirror
You are a hazard to humanity, attempting to gloss over life threatening engineering flaws as you you, and rude besides. Not to mention, you seem to make a point of parading your ignorance. Please do everbody a favor and test Darwin's Jet yourself according to your pet theories, whether or not you feel qualified.
ducted fans lack a compression stage if I'm not mistaken, and the thrust they produce is no greater than that of a propellor?
The thrust that this so-called electric jet produces is no greater than the particular form of propeller that is called a "ducted fan". So no, you are not mistaken in that exact observation but you went on to draw the wrong conclusion nonetheless.
To tell the truth, I am awed at how well aeronautical fraud actually works. It has never been in short supply, ever since the days of Icarus. The most remarkable form of aeronautical fraud is the kind that perps talk themselves into believing, and we can just hope that they don't take out too many innocent bystanders.
I think there's room to consider an electric jet as a new twist on the "jet engine" only without combustion.
Sorry, that makes it not a jet engine, by definition.
Hey, I have only one suggestion for somebody as smart as you. Build and fly your own experimental aircraft. And name it "Darwin's Jet".
"The electric jet engines work like turbofan jet engines in a regular passenger jet. They suck in air, compress it and push it out the back.
But wait, that is exactly what a ducted fan does. Well, playing a bit fast and loose with the terminology, aren't they? A minimal amount of compression goes on, while the relevant effect is actually acceleration of a mass of air. The higher velocity air requires less cross-sectional area to transport equivalent volume (the volume that is swept by the cross sectional profile of the ducted fan as it moves through space) and so, the throat of the ducted fan is narrower than the intake, somewhat like a turbofan but for different reasons. The purpose of compression is to heat the air, to prepare it for the combustion reaction. The electric ducted fan has no such purpose for compressing air.
However, the compressor fan in the front is not turned by a gas turbine, but by a high performance electric motor.
A jet engine is a combustion engine. No combustion, no jet engine.
Therefore, they run much quieter and completely emission-free...
And in this altered reality, they are much more efficient at creating marketing spin than boring old electric motors.
The plane in the video is not flying with max forward speed ...
And why not? Presumably because it can't.
It is hovering, hence the jets point a bit downward ...
"A bit"... come on, that is not "a bit".
Get over it.
You get over it, you are the one with the shitpost trigger finger.
Btw. they have several videos, perhaps you warched the wrong one.
I watched several videos, including the 1/5th scale model video, which is the most informative because it shows the most forward flight. When flying forward at maximum speed, it is clear that the flight characteristics are 1) very inefficient 2) not primarily the characteristics of an aeroplane, but more akin to a quadcopter. This has two implications: 1) the touted aerodynamic efficiency due to the wings is not going to happen 2) the safety factor of being able to glide to a landing is not going to happen.
There you have it. However much you rant about it, this flying machine remains a close relative of the flying brick.
In that case, would the lift from the airframe moving forward would be much more than an equivalent helicopter and thus the range would be much better?
... This issue could be somewhat fixed by changing the forward ducted fan assembly into a real canard as in the concept animation, but with all the junk attached it would be a contender for world's least efficient canard wing, and fragile to boot.
Just add plain airfoil canards on the outer ends of the forward nacelles and you will have an aircraft with fully functional canards.
Just add plain airfoil canards on the outer ends of the forward nacelles and you will have an aircraft with fully functional canards.
But that is not what was demonstrated, and it will still fly like a brick without hugely increased foil area, including the rear foil. Do not underestimate the disruptive effect on lift of the turbulence around the motor housings. By the time the foils are large enough to glide safely or even significantly increase endurance, this design is back to being just a VTOL canard plane, not remotely in the ballpark of a flying car. Clearly the promoters are trying to pull one over on the public: this thing is really just an electric quadcopter with ducted fans, it will never be an airplane or a flying car.
Obviously while it is more or less hovering the jets are pointing in an angle downwards. When it is flying with full speed the jets will be more or less horizontal...
Dead wrong. Those motors will never be horizontal in straight and level flight, no matter how fast the thing goes. There is no front wing for crying out loud. What do you think will keep the front end up, wishes? And the back wing is just a stick. Look at the video closely. Even at maximum forward speed, the fans are still angled down at roughly 40 degrees. Seems, you really want to believe in this. Well I have a suggestion: volunteer to go for a ride, since you think it is safe. Maybe the power won't run out, no motors will overheat, no fuse will blow, no wires will vibrate loose, and you will be fine.
And they aren't jets. And you likely do not have the slightest clue what wing loading is. Feh.
There are also graphics showing the engines pointed straight back.
Wishful thinking. Try that in the air and it will plummet like a rock.
Modding -1 "disagree" will not make that thing any more airworthy. Lose power and it will nosedive spectacularly, ending in a mangled heap of plastic and meat.
There are also graphics showing the engines pointed straight back.
Wishful thinking. Try that in the air and it will plummet like a rock.
aren't you supposed to spout this kind of: "Man will never fly!" garbage _before_ it's been clearly demonstrated. The video shows it taking off and in forward flight
To call that demonstration "forward flight" you need to be charitable or gullible. Look again. The front motors are pointed straight down. That does not qualify this thing as an airplane at all, it qualifies it as some kind of helicopter. Helicopters also can fly forward, but they are not airplanes, and they suck for fuel efficiency. Like this thing, which claims to be fuel efficient because of its wings, but don't be stupid. Look at it, it doesn't even have wings on the front and the back wing is little more than a spoiler.
You can see what is going on more clearly in this video of their 1/5th scale model (i.e., 1/125 weight) where the motors are always angled down at least 40 degrees, otherwise it will fall out of the sky. If it had proper wings the motors would point straight back. All that downward vectoring comes straight out of the battery life, which is the main selling point of this concept. Well, if you are a snake oil collector then feel free to buy this concept.
Some wise person said "an open mind is a fine thing, but let it not be gaping".
Haha, that's funny. This thing will never transition for forward flight, except as a forward hover. It doesn't even have a forward wing for crying out load and the rear wing loading is absurd, not to mention the profile drag. But thanks for doing your part to provide an in-the-wild demonstration of the credulous thing.
Well, Red Hat is buying into a lot of crap that is only marginally Linux, and is far from what you could call obviously reliable. Like Openstack, Ceph, Gluster, that kind of thing. When you build your house high enough on a foundation of shit, it eventually sinks into it. Like, Openstack actually depends on MySQL for distributed consistency, how far do you think that frisbee will fly?
Openstack, more probably.
I guess we'll never hear what these things sound like. Anyone care to speculate on the decibel level when your neighbor lifts off his driveway?
Oh, I don't know, roughly akin to a dremel tool on your bicycle helmet?
miles and kilometres are not the same length?
Actually, they are, per inch.
On the whole, aircraft actually get better gas mileage than ground vehicles
Planes do, not helicopters. You need to be charitable and more than a bit credulous to call this thing a plane.
Sorry but a propeller in a cowling is not a "jet engine"
It is a "ducted fan" and so is a jet engine. But you are right about the marketing.
aren't you comparing this vehicle to a plane when perhaps it should be compared to a helicopter?
It a fuselage optimized for forward flight and it has wings. Therefore it is trying to appear to the view as a plane. It is really a helicopter, as you say, and as I implied by calling the show a "hover demo".
In that case, would the lift from the airframe moving forward would be much more than an equivalent helicopter and thus the range would be much better?
No, for several reasons. The lift from the the slippery egg shape will be roughly zero except at stupidly high angles of attack and stupidly high speeds, so forget that. The lift from the main, rear wing will be pathetic because of the massive disruption of flow causes by the ducted fan housings. And the wing loading is way too high anyway. The video optimistically implies some kind of laminar flow over the wing and through the fans, but the there is so much structural junk in that way that I will have to call that pure fantasy. That rear wing assembly has airfoil efficiency roughly equivelent to a backyard barbeque.
And that is not the worst problem. Aerodynamically, the worst (of many) problems with this concept design is, the forward canard will generate exactly zero lift. All the lift at the front comes from the vertical thrusters, which will need to stay running (at high speed and power consumption no doubt) the entire time that the plane attempts to maintain efficient horizontal flight. This issue could be somewhat fixed by changing the forward ducted fan assembly into a real canard as in the concept animation, but with all the junk attached it would be a contender for world's least efficient canard wing, and fragile to boot.
Obviously, unpowered gliding is a complete non-starter with this configuration. At best, some inefficient form of foil-assisted forward flight will be possible, most likely not efficient enough to justify the additional weight and wetted surface of the real airfoil.
if the engines die you can't "glide" it back to a landing. However the massive redundancy (36 fans) would prevent that from being the point of failure (but the battery, power electronics might be)
You might want to upgrade that "might" to a "will". Consider the case of flying over water with unexpected headwind that lengthens the trip past the battery endurance, or countless other scenarios that come up regularly in real life.
That's where the parachutes come in I guess.
I suggest, some healthy skepticism will come in even more handy in terms of minimizing loss of life.
Since I'd rather have a (safe, easy to fly) helicopter than a plane, I think I'd buy this to go (short) island hopping in the South Pacific. :)
You're a great straight man, you know that? Exactly the scenario I mentioned above...
If you plastered it with solar cells, how long would do you think it take to charge?
How much time have you got?
This demo is just a hover demo, the wings are actually just pure decoration for promo purposes. Not to say that a hover demo is an easy feat, but the cool looking slippery fuselage is not doing anything useful in an aerodynamic sense, rather it is purely for social engineering at this point. Doubt me? Look at the canard, it is not even an airfoil by any stretch of the imagination. This aircraft is absolutely incapable of gliding, it would immediately dive straight down if you tried to do so, with spectacular results.
Given that this is just a hover egg, maybe optimize it for that? The concept render actually shows an airframe that could be capable of some kind of glide ratio, but from the look of it, only at really high speed. Trying to flare out for a standard runway landing would most likely be a life threatening experience. With all those ducted fans, the profile drag will be through the roof. Glide ratio, maybe 5 to 1, optimistically, unless the profile drag can be reduced by some as-yet uninvented magic. By comparison, a garden variety Cessna gets 9:1, which means that landing without power already requires some skill. With 5 to 1, you basically need to be a Chuck Yeager to walk away from it.
Might as well just be honest about it and lose the wings entirely. Simple sticks will do, like the canard, and save some weight. Then what is the remaining reason for having such small fans? Small fans are less efficient than larger ones, meaning the batteries will run out considerably faster than some more practical design.
Or move there. The difference is starting to move into the embarrassing zone. Check your kevlar vest at the border, and oh, if you forgot to buy your travel medical it won't cost you $30k to get back home if you happen to break your leg running away from a moose.
Frankly, I find the quality and content of TED talks embarrassing. Hmm, why should I feel embarrassed about that? I don't know, but I do. So often verging on intellectual fraud. A venue for self-promotion and mutual intellectual masturbation. Well, I guess it keeps them off the street.
I will have to call that a "whoosh".
If you do not care about unibody design then feel free to drive one of those old cars that had frames and tended to kill you more. And if you can't see how that relates to handset design then just don't worry, be happy.
thanks to a couple of decades of convergent evolution, there is often a reasonably sane quasi-default layout.
Actually, the default for DVR is insane. There is no good reason to have a stop button right next to play/pause when you almost never want that. Just lose the stop button. I mean, what does it do that pause, eject and power don't already cover? Or at least, place it well away from the useful buttons.