Is battery energy more efficient with air speed lift from a wing, like traditional aircraft, or from air suspension, like a helicopter? Does the mass/energy of a gasoline power train (including fuel & motor) exceed an electric power train?
I guess I'm wondering about the viability of electric power for flight at all. Drones are useful for some applications with light payloads and conducive environments, but when you need to lift a substantial payload, like me, isn't battery just too little power density?
* fixed wing flight is faster, has a longer range, and is "more efficient" than rotorcraft
* gasoline, for now, has roundabout 50x as much energy per mass ("specific energy") as batteries.
* however, electric engines are 4 to 10 times more efficient.
* so basically, with electric power for now you can only fly about 10% to 20% as long/far as with avgas - ok for a few specific applications, but not yet good enough
* on the other hand, electric engines are much simpler, lighter, and more reliable than piston engines (turbine engines are also very reliable, though)
(* note that one needs sufficient specific energy to fly long/far enough, and sufficient specific power e.g. for takeoff)
* lastly, batteries appear to improve at around 4% to 8% per year (some incremental improvements, but mostly switching to new "chemicals", eg lead to NiMH to Li-...), so electric flight could become really interesting in the next two, three decades.
Helicopters are aerodynes just like fixed-wing aircraft, deriving lift from aerofoil speed. They are just less efficient because in traditional single-rotor designs only part of the rotor disk is generating lift at any one time ( and part is stalled ) and of that part needs to be directed as propulsive thrust.
Some helicopters have employed short wings to offload the rotor.
A wingless VTOL aircraft such as the Flying Bedstead, or the Lunar Lander testbeds, is a non-aerodyne and is even less efficient because it relies on a small volume of highly-accelerated air for lift versus displacement of a large quantity of slow ( roughly speaking ).
My understanding is that electric motors are necessary because they can change speed faster than an internal combustion driven motor in order to maintain balance. What I don't understand is why we don't see more drones or similar flying machines using a small gasoline generator driving electric propellers to get high energy density combined with maneuverability.
if you interested in these type of vehicles register here http://bit.ly/2pdeml5 for the public co-founder program we will be doing a pre-salle soon, the electrical vehicle will cost around $40k.
they call it "flying car" because technically could replace the "car functionality" on this case more a "motorcycle functionality" with an aerial vehicle.
Probably should be called flying motorcycle but on a marketing level doesn't have the same impact.
Unless absolutely necessary, putting drive motor mechanisms and flying mechanisms on the same package is a waste of efficiency.
Why have your engine pull the extra weight of your propellers...and why have your propellers lift a drivetrain?
I get your point that "flying car" may be a tad misleading, but my guess is that they made this first iteration a "water vehicle" to get around the majority of regulations while still getting a product into the field to test and (perhaps) make some money while they're at it.
Much harder problem, if by that they mean "flyable without a pilot's license". You need to tackle reliability, then AI on the order of self-driving cars, then regulators, then infrastructure. Even Tesla is having a hard time making a slightly different kind of car.
Why tackle all the hard problems at once? Why not make a self-landing helicopter, or a "normal" electric aircraft (like Tesla but for planes), or a reliable and cheap (!) experimental VTOL craft? I can't help but think that the only reason to do it this way is because you're selling sizzle, not steak.
Also, at this point of time, maybe we can engineer good specs and good price into the product, but we cannot overcome human factors.
- Riding in strong winds.
- Loss of control over populous areas.
- Higher risk of crime in a vehicle that has no boundaries like roads and dividers.
The most likely solution is to make a cloud connected one which refuses to fly in or into bad weather, automatically lands during emergencies etc. But then that will necessitate some sort of remote control over the vehicle, leading to a host of other issues related to lack of privacy.
Looks like a silly contraption to me, far too slow to replace a car (and earn the misleading article title). I'd find a hybrid quadcopter / https://en.wikipedia.org/wiki/Ground_effect_vehicle project more worthwhile. Take off and land like a quadcopter, then fly fast and efficiently using the ground effect. Compensate for uneven ground with the down facing rotors...
There is an interesting correlation between multirotors and 15 minute flying times. It always seems to take an abnormally large battery pack (and correspondingly less payload) to get to 20 or 30 minutes.
* 15min flight time
* I'd estimate 5 miles range
* if you roll it into the water and any part of the battery is exposed you'll be electrocuted and likely drown.
Fixed wing is the only way to go for efficiency and I can't imagine anything other that a hybrid having more than 45minutes flight time @ <40knots.
It's deffo possible to make a high lift, low speed fixed wing that has a short takeoff/landing requirement. There are elec ultralights that do this today.
This whole obsession with elec/'coter design baffles me - even with the most optimistic math assumptions it is a terrible product.
Many readers of the linked article won't understand the meaning of "ground effect" and what role it plays in the video. It's possible to create a demonstration flying craft that can't ascend above the ground effect regime, but still create an impressive video.
In short, if the video had shown ascent to an altitude of, say, 100 feet, I would be much more impressed.
Regardless of ground effect lift, 100ft altitude is well into the "dead zone" for vehicles like this. Too high to survive a crash and too low to use a parachute.
Looking forward to seeing flying car crashes. Lookout below! Seriously how do you avoid killing people innocently underneath one of these when it fails? Build "roads" in the sky like in Back To The Future?
So in the next 8 months? Seems like Google has an interesting pipeline of novel new products, but I wonder if any this will ever see the light of day, let alone by the end of the year.
I wonder why Google is doing all this pre-launch marketing hype. Usually this is the playbook that startups use to hype up VCs for funding rounds. Maybe just for PR and branding?
Reminds me of UBeam's "we plan on launching publicly this year!" (said in 2015, 2016, and now 2017)
[+] [-] 11thEarlOfMar|9 years ago|reply
Is battery energy more efficient with air speed lift from a wing, like traditional aircraft, or from air suspension, like a helicopter? Does the mass/energy of a gasoline power train (including fuel & motor) exceed an electric power train?
I guess I'm wondering about the viability of electric power for flight at all. Drones are useful for some applications with light payloads and conducive environments, but when you need to lift a substantial payload, like me, isn't battery just too little power density?
[+] [-] FabHK|9 years ago|reply
* fixed wing flight is faster, has a longer range, and is "more efficient" than rotorcraft
* gasoline, for now, has roundabout 50x as much energy per mass ("specific energy") as batteries.
* however, electric engines are 4 to 10 times more efficient.
* so basically, with electric power for now you can only fly about 10% to 20% as long/far as with avgas - ok for a few specific applications, but not yet good enough
* on the other hand, electric engines are much simpler, lighter, and more reliable than piston engines (turbine engines are also very reliable, though)
(* note that one needs sufficient specific energy to fly long/far enough, and sufficient specific power e.g. for takeoff)
* lastly, batteries appear to improve at around 4% to 8% per year (some incremental improvements, but mostly switching to new "chemicals", eg lead to NiMH to Li-...), so electric flight could become really interesting in the next two, three decades.
[+] [-] dingaling|9 years ago|reply
Helicopters are aerodynes just like fixed-wing aircraft, deriving lift from aerofoil speed. They are just less efficient because in traditional single-rotor designs only part of the rotor disk is generating lift at any one time ( and part is stalled ) and of that part needs to be directed as propulsive thrust.
Some helicopters have employed short wings to offload the rotor.
A wingless VTOL aircraft such as the Flying Bedstead, or the Lunar Lander testbeds, is a non-aerodyne and is even less efficient because it relies on a small volume of highly-accelerated air for lift versus displacement of a large quantity of slow ( roughly speaking ).
[+] [-] mcculley|9 years ago|reply
[+] [-] titojankowski|9 years ago|reply
Check out this section on Electric/Eco friendly Planes from the famous "Sustainable Energy Without the Hot Air": http://withouthotair.com/cC/page_278.shtml
If you like mathematics you'll also enjoy the chapter on Planes: http://withouthotair.com/c5/page_35.shtml
[+] [-] elmar|9 years ago|reply
[+] [-] phreeza|9 years ago|reply
[+] [-] elmar|9 years ago|reply
Probably should be called flying motorcycle but on a marketing level doesn't have the same impact.
[+] [-] scld|9 years ago|reply
Why have your engine pull the extra weight of your propellers...and why have your propellers lift a drivetrain?
I get your point that "flying car" may be a tad misleading, but my guess is that they made this first iteration a "water vehicle" to get around the majority of regulations while still getting a product into the field to test and (perhaps) make some money while they're at it.
[+] [-] dTal|9 years ago|reply
Hard problem.
>personal aircraft
Much harder problem, if by that they mean "flyable without a pilot's license". You need to tackle reliability, then AI on the order of self-driving cars, then regulators, then infrastructure. Even Tesla is having a hard time making a slightly different kind of car.
Why tackle all the hard problems at once? Why not make a self-landing helicopter, or a "normal" electric aircraft (like Tesla but for planes), or a reliable and cheap (!) experimental VTOL craft? I can't help but think that the only reason to do it this way is because you're selling sizzle, not steak.
[+] [-] mlpinit|9 years ago|reply
[+] [-] kumarvvr|9 years ago|reply
Also, at this point of time, maybe we can engineer good specs and good price into the product, but we cannot overcome human factors.
- Riding in strong winds. - Loss of control over populous areas. - Higher risk of crime in a vehicle that has no boundaries like roads and dividers.
The most likely solution is to make a cloud connected one which refuses to fly in or into bad weather, automatically lands during emergencies etc. But then that will necessitate some sort of remote control over the vehicle, leading to a host of other issues related to lack of privacy.
[+] [-] elmar|9 years ago|reply
https://news.ycombinator.com/item?id=14167870
[+] [-] FabHK|9 years ago|reply
http://www.volocopter.com/index.php/en/
(Disclaimer: I have crowd-funded invested a modicum in it)
[+] [-] hajile|9 years ago|reply
https://www.youtube.com/watch?v=EPC8qElrG-I
[+] [-] JustSomeNobody|9 years ago|reply
Also, not looking forward to the headlines about disputes[0] about airspace over people's property.
Edit: clarification
[0] Dude with a shotgun vs dude on a flying "car".
[+] [-] giarc|9 years ago|reply
[+] [-] lazyjones|9 years ago|reply
What does the Kitty Hawk compete with?
- small helicopters cost $XX.XXX and have been available for many years. Proven technology, though unsafe. E.g. https://en.wikipedia.org/wiki/Mosquito_Aviation_XE
- small airplanes for the crazy? https://www.youtube.com/watch?v=KLgR3Ipo-Ng
- flying cars that can actually drive on the road? https://www.aeromobil.com/flying-car/
It looks like a toy in comparison, to be operated by quadcopter enthusiasts for 5 minutes ... Perhaps they should call it "flying golf cart"?
[+] [-] elmar|9 years ago|reply
I speculate the kitty hawk vehicle will have 10-15 minutes airtime and will cost around $100k
[+] [-] falcolas|9 years ago|reply
[+] [-] RandyRanderson|9 years ago|reply
Fixed wing is the only way to go for efficiency and I can't imagine anything other that a hybrid having more than 45minutes flight time @ <40knots.
It's deffo possible to make a high lift, low speed fixed wing that has a short takeoff/landing requirement. There are elec ultralights that do this today.
This whole obsession with elec/'coter design baffles me - even with the most optimistic math assumptions it is a terrible product.
[+] [-] lutusp|9 years ago|reply
In short, if the video had shown ascent to an altitude of, say, 100 feet, I would be much more impressed.
[+] [-] nradov|9 years ago|reply
[+] [-] hdhzy|9 years ago|reply
[+] [-] coldcode|9 years ago|reply
[+] [-] avryhof|9 years ago|reply
[+] [-] BerislavLopac|9 years ago|reply
[+] [-] elmar|9 years ago|reply
[+] [-] agumonkey|9 years ago|reply
ps: lakehawk
[+] [-] Luuseens|9 years ago|reply
[+] [-] dang|9 years ago|reply
[+] [-] ithinkinstereo|9 years ago|reply
I wonder why Google is doing all this pre-launch marketing hype. Usually this is the playbook that startups use to hype up VCs for funding rounds. Maybe just for PR and branding?
Reminds me of UBeam's "we plan on launching publicly this year!" (said in 2015, 2016, and now 2017)
[+] [-] TulliusCicero|9 years ago|reply
[+] [-] maxerickson|9 years ago|reply
https://kittyhawk.aero/faq/
I expect it will barely be a product when it launches, certainly not one with wide appeal.
[+] [-] unknown|9 years ago|reply
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