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Derswede

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Someone beat an airplane with an Ugly stick and it survived. One positive thought is that such research may drive the development of a system we can use in our craft, the sooner the better. As long as they are not throwing MY money at the project, let 'em play!

Derswede
 

lr27

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Because there's too much fuel and not enough CO2 in the world.
 

Tiger Tim

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Thunder Bay
While I doubt this cycle of VTOL flying taxi services (it seems to be a fad every other decade or so) is going to actually hit the mass market, it’s nice to see they’re technologically a little more capable every time around.
 

Aesquire

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Rochester, NY, USA
That is an interesting approach.

Never mind any air taxi flying car applications that no city in the U.S. has the infrastructure of regulation to have work. They may be serious, but I'll just call it investment bait, for now.

I look forward to see if it can fly. It can hover in ground effect without hanging from a crane, so that's ahead of several famous previous machines. ( cough, Moller )

Starting with a conventional airplane & adding a multicopter with pivoting thrust, may be a solid, conservative approach to the problem.
 

Sockmonkey

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I really wish they would quit with the tiltrotor nonsense and rotate the passenger compartment instead so you can land the thing on it's butt and not need a dozen motors and props just to make sure it can survive the loss of one.

There. Two bigger and more efficient rotors and you can still control the thing in hover with the elevons if you lose one.
 

blane.c

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capital district NY
I really wish they would quit with the tiltrotor nonsense and rotate the passenger compartment instead so you can land the thing on it's butt and not need a dozen motors and props just to make sure it can survive the loss of one.

There. Two bigger and more efficient rotors and you can still control the thing in hover with the elevons if you lose one.
Bad attitude.
 

Himat

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Norway
Video:
[video=youtube_share;GBcLIr-pc4k]https://youtu.be/GBcLIr-pc4k[/video]
 

BJC

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Oct 7, 2013
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97FL, Florida, USA
I really wish they would quit with the tiltrotor nonsense and rotate the passenger compartment instead so you can land the thing on it's butt and not need a dozen motors and props just to make sure it can survive the loss of one.

There. Two bigger and more efficient rotors and you can still control the thing in hover with the elevons if you lose one.
...if it has enough power to hover on one. Should have pretty good acceleration with a T:W of 2 or more.


BJC
 

Sockmonkey

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double entendre
Okay, I'm a bit snarky about it. It's two things really. I see a new one every other week and they never go anywhere. Second is the fact that so many of them only do it halfway, in that they try and shape it like a regular plane even when it's a design that needs fly-by-wire to be stable in hover. Once you're doing that, you should be exploiting it fully by using a simpler, more robust airframe that would normally be unstable. The blackfly did it right in this regard. The EVTOL should ditch the wings and tail, and use a lifting body like the facetmobile. It's not like an air taxi needs to have a "fun" performance because that's not it's job.
 

blane.c

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Okay, I'm a bit snarky about it. It's two things really. I see a new one every other week and they never go anywhere. Second is the fact that so many of them only do it halfway, in that they try and shape it like a regular plane even when it's a design that needs fly-by-wire to be stable in hover. Once you're doing that, you should be exploiting it fully by using a simpler, more robust airframe that would normally be unstable. The blackfly did it right in this regard. The EVTOL should ditch the wings and tail, and use a lifting body like the facetmobile. It's not like an air taxi needs to have a "fun" performance because that's not it's job.
Yes a lot of ideas burning holes in the sky. I am looking forward to the one at; http://www.jobyaviation.com/#. It is among the most serious.
 

blane.c

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Joby was the electric motors Dale Kramer used in the last version of the electric Lazair that I am aware of. Joby had a very proud picture of the multi rotor they were developing on their website a couple of years ago, I don't see it anymore.
 

Andy_RR

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Melbourne, Australia
I like seeing people spend their money demonstrating stuff like this. It may not be immediately feasible but it offers many lessons even for the perceptive bystander.

I have been doing a lot of number-crunching and modeling of my own eVTOL concept and one thing that becomes immediately obvious is that it's only just on the cusp of viability with current electric and battery technology. It's definitely possible but there's no headroom for half-arsery in any of the design areas.

To make something meaningfully useful (i.e. with some range) aero and structural efficiency in both modes of operation are essential. It's mainly because it costs a substantial proportion of the battery energy to get airborne and return to the ground safely.

And those that are adamant they know better how these things should look will only be credible when they present their own ideas fully formed and calculated along with working assumptions. It's definitely not an easy task!
 

blane.c

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I think *hitcan the batteries basically. I mean sure you got some batteries, enough to keep the greenies confused that it is a battery powered electric but really you have to have a gas sucking generator on the vehicle to make it practical. The present battery energy density is just an insurmountable obstacle in the way of advancing the rest of the technology. Then the marvel of the system is going to be the controller that integrates the battery power and the generator power and charges the batteries and allows differential power to various motors. But when you add gas to a multiple electric motor powered vehicle, now you have something. Maybe an energy source comes along in the future that can replace the gas generator but for now it allows the rest of the systems to move forward.
 

Andy_RR

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I think as tempting as a IC-hybrid style power system seems, it does have a bundle of its own complexities and compromises. For starters you've just upped the complexity by at least a factor of two. You need to add significant cooling systems (and drag) into the equation (unless you go turbine, perhaps). More significantly you need to carry at least twice the weight in electrical machines than you do for a battery only solution and you need to deal with engine noise, vibration isolation and heat management, fuel systems and pumps. None of this is new news but it all adds to the plates you're already spinning to get a design together. Oh, and you'll need to carry some (high-power density = heavy and expensive) batteries anyway...

Generally not as cut-and-dried a decision as you might think.
 

Vigilant1

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Yes, batteries have low energy density and are expensive. Recharging them also lowers the available utilization rate.
IC engines increase complexity and cost (especially if they only drive a generator for a bunch of electric motors--another conversion, less efficiency).
A little taxi-bird like this is going to be scooting primarily around built-up areas, so offload the whole energy conversion and storage problem to where it can be done cheaply and reliably--the ground. Pennies per kilowatt hour. Beam up the energy to the craft in the RF spectrum. The bird is already draggy and awkward enough that some Yagi arrays pointed back at the ground station would hardly be noticed, and wires built into the composite structure could also help. Include a Faraday cage to reduce occupant exposure ("Does it feel warm in here to you?") and everyone will be happy. Avoid the absorptivity spectrum of water/water vapor and it would be fine even in IMC.
 

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