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http://www.airbusgroup.com/int/en/story-overview/future-of-e-aircraft.html


As part of this roadmap, Airbus Group is currently involved in a number of technological programmes whose breakthroughs could eventually also be applied to an all-electric helicopter and a 90-seat-passenger regional airliner with fully electric or hybrid propulsion.

 

 

  • The E-Fan, a fully electrically-powered aviation training aircraft
  • The E-Thrust concept study based on a distributed propulsion system architecture, which would be the basis of a fully hybrid and electric commercial aircraft in the long term
  • The DA36 E-Star 2 project, two seat hybrid electric motor aircraft, in conjunction with Diamond Aircraft and Siemens
  • Applications in the field of Unmanned Aerial Systems as shown by the Quadcruiser prototype, which combines hover capabilities with the cruising speed of an aircraft

 

 

E-Fan propulsion is provided by two electric motors with a combined power of 60 kilowatts, each driving a ducted, variable pitch fan. The duct increases the static thrust, it reduces the perceived noise and improves safety on the ground. With the engines located close to the centreline of the aircraft, the E-Fan has very good controllability in single-engine flight.

 

 

The arrival of superconductivity

The DEAP project team also plans to use superconductivity technology. MRI scanners in hospitals, for example, use superconductive electro-magnets, and the researchers now want to benefit from their application in aerospace.

When current flows through an ordinary conductor, like copper wire, some energy is lost as heat due to resistance in the electrical conductors. Superconductivity is a phenomenon of exactly zero electrical resistance, which occurs in certain materials when they are cooled below a critical temperature. Superconductive material can therefore conduct electricity without energy loss.

 

 

 

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Yes but it comes with an amazing new invention chaps...

They call them rechargable batteries. Don't worry a couple of metres of cable should be enough.

They say one day we may even have telephones in our pockets powered by these special batteries.

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my god the future has caught up with me

beam me up scotty !!

 

 

 oh and by the way Dai its called a rallonge (forgive the spelling , i only speak french fluently , writing it is all together another thing)

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I bought Lionheart's Avelina electric aircraft a bit ago and said "this won't be long'...but seriously...less than a year?!

 

 

"The DEAP project team also plans to use superconductivity technology... ... Superconductive material can therefore conduct electricity without energy loss."

 

 I'm very curious how they plan to use super cooled "superconductivity" to reduce "energy loss" without using a fark ton of energy to keep the superconductive components cool. Super-Insulation?

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I'm very curious how they plan to use super cooled "superconductivity" to reduce "energy loss" without using a fark ton of energy to keep the superconductive components cool. Super-Insulation?

 

 

Well there are no room temperature superconductors yet. The record is held by Sulphur Hydride I believe, at minus 83 degrees. That's only if it's under great pressure.

 

I guess they must have something in mind, a feasible way superconductivity could be beneficial.

 

There probably wouldn't be as much coolant as you think. It would need to be topped up of course.

 

 

 

 

 

 

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Found this...

 

 



The second enabling technology is, if anything, even more challenging: the development of a superconducting distribution network. The requirement for this stems from the high voltage and megawatt power range of the E-Thrust propulsion system and the need to reduce the resistance of conductors. In practice, this means cooling the wires to very low temperatures, either using cryogenic fluids or a cryocooler (a mechanical heat exchanger based on the Stirling engine). Although superconductors are used today in MRI scanners and Stirling coolers have been designed for spacecraft, these are not off-the-shelf items readily applicable to aircraft power distribution systems, which is why this is one of the key 'enabling technologies' for E-Thrust.

One could not help but be impressed by a demonstration item in the Airbus pavilion at Farnborough: a levitating, briefcase-sized object incorporating a superconducting magnet floating a centimetre or so above a desk. According to Fouquet, it required a daily cryogenic top-up to maintain its apparently effortless hover. Arguably more important was the display of cables it carried, which compared a large cross-section copper conductor with its flimsy equivalent in superconducting wire. The weight saving alone would probably account for the difference between carrying 100 passengers or just the pilot!

 

 

 

 

Light weight cryocoolers are used on satellites don't forget. They can weigh mere ounces.

 

http://eandt.theiet.org/magazine/2014/10/rise-of-electric-aircraft.cfm

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  • 2 weeks later...
  • 2 weeks later...

The temperature of space being an advantage or not for satellite cryocoolers, the Airbus scientists and engineers clearly know what they are doing, otherwise they wouldn't have invested the resources they have in the project. Clearly they regard superconductivity as a viable technology, a technology suitable for the application they intend.

I'm not sure how much of an advantage space at 3 Kelvin offers a satellite cryocooler to be honest, I'd need to research that. Don't think it's as simple as it might appear.

Satellites are heated by the sun to very high temperatures due to thermal radiation [no convection or conduction of course]. They are very cold on the opposite side, but they do rotate precisely for that reason. In addition they use multiple layers of Mylar in an attempt to keep the satellite at a reasonable temperature.

It's not just the satellites electronics that generate heat. There's a very nice fusion reactor heating up the satellite and any cryocooler on board.

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There's a very nice fusion reactor heating up the satellite and any cryocooler on board.

Oh, someone has built a functioning fusion reactor already? I hadn't heard that. Please provide details - I can hardly wait to read about it.  :rolleyes: 

I'm pretty sure you meant fission, not fusion, though that's not entirely right either in most cases.  Most of the satellite reactors that have been used are not even true fission reactors, but rather a non-critical, radioactive mass, using decay heat to generate relatively small amounts of power through an array of thermocouples.

 

Satellites are heated by the sun to very high temperatures due to thermal radiation [no convection or conduction of course].

There can, of course, be conduction through the materials of the satellite once the outer parts are heated by solar radiation.

As you say, all the heat from the sun is via radiation heating. What happens after that gets a little more complicated, but as you indicate, reflective heat shields, insulation and rotation do most of the heavy lifting - heat prevention rather than heat removal.

Electronics heat is a good example of something in a satellite that does need cooling. Not sure how they carry the heat away, but probably by some combination of conductive heat sinks and circulating coolant, either gas or liquid. Conduction through skin panels on the cold side would make a very effective ultimate heat sink. If natural circulation could somehow be achieved that would be very efficient, but not sure it can be in zero-g.

I don't believe many satellites have reactors at all; a few dozen are claimed, plus more in classified applications, no doubt, but most rely on photovoltaic solar panels. I'd guess that typically only deep space probes that are expected to travel too far from the sun for solar panels to provide the necessary power are equipped with them.

Satellite reactors might in fact need some cooling but I suspect the devices themselves are pretty temperature tolerant. If suitably located away from heat sensitive things and suitably shielded and insulated, I'd be surprised if they needed very much in the way of cooling.

For that subset that are true fission reactors, if designed with a negative temperature coefficient, they would be at least somewhat self-limiting; the reactivity, and thus the rate at which heat is generated, will diminish as temperature increases. Decay heat might force the need for some external cooling anyway, depending on the fuel used and the energy and half-lives of the daughter products - a negative temperature coefficient can't help with that. 

 

When current flows through an ordinary conductor, like copper wire, some energy is lost as heat due to resistance in the electrical conductors. Superconductivity is a phenomenon of exactly zero electrical resistance, which occurs in certain materials when they are cooled below a critical temperature. Superconductive material can therefore conduct electricity without energy loss.

True as stated, but there's more to it. The electric motors drive something, I guess the fans. Whatever mechanical energy is produced by the motors is in fact electrical energy that is "lost", i.e. converted to mechanical energy and possibly some heat energy of friction. Cryogenic technology can reduce the normal electrical losses of the motor from resistance to zero, but cannot provide a free lunch - if you do 60 KW of work with the motor, it will consume 60 KW of electrical energy. The motor can be made more efficient by avoiding the loss of energy that would normally occur through resistance heating but an electric current equivalent to the work done by the motor will have to be supplied to it constantly from some source. The article isn't talking about it but they're planning to get approximately 60 KW from somewhere.

If the motor is AC, there may also be electrical losses through inductive and capacitive reactance and cryotechnology can't help with that, but they may well be DC. If so, those things are not a factor in steady state operation, only when load is changing.

 

...the Airbus scientists and engineers clearly know what they are doing, otherwise they wouldn't have invested the resources they have in the project.

Call me cynical but often in these cases it's the accountants who know what they are doing, taking advantage of government subsidy money for green technology projects. If that dries up before the aircraft flies it will be dropped faster than you can say Solyndra.

John

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Oh, someone has built a functioning fusion reactor already? I hadn't heard that. Please provide details - I can hardly wait to read about it. :rolleyes:

I'm pretty sure you meant fission, not fusion, though that's not entirely right either in most cases. Most of the satellite reactors that have been used are not even true fission reactors, but rather a non-critical, radioactive mass, using decay heat to generate relatively small amounts of power through an array of thermocouples.

 

 

Have you woke up yet John?   :)  Just kidding. Clearly I was referring to the rather large and almost perfectly spherical ball of hot plasma  at the centre of our solar system, with a mas of 330,000 times that of the Earth. And yes, it's a FUSION reaction.

 

The Sun! The Sun's radiant heat increases the temperature of orbiting satellites. Not forgetting the heat generated by the electronic components on-board of course.

 

This is why quite sophisticated thermal control mechanisms are employed. It's also why, If I remember correctly, Hydrazine is used as a satellite propellant, in order to avoid boil-off but don't quote me on that, I'm no expert.

 

Satellites incorporate both passive and active cooling strategies, dependant on the amount of heat that has to be removed. And the amount of heat that has to be removed depends on the satellites operational mode, which devices are functional which aren't, whether the satellite is in direct sunlight or shadow. In short, radiant heat from the sun heats satellites, and thus any cryogenic material on board too. Therefore, I would imagine insulation is just as important for satellites as here on the Earth. But again, I'm no expert.

 

There can, of course, be conduction through the materials of the satellite once the outer parts are heated by solar radiation.

 

Of course there can. Which was why I was referring to satellites and any coolant on board being heated by radiant heat from the Sun.

 

Electronics heat is a good example of something in a satellite that does need cooling. Not sure how they carry the heat away, but probably by some combination of conductive heat sinks and circulating coolant, either gas or liquid. Conduction through skin panels on the cold side would make a very effective ultimate heat sink. If natural circulation could somehow be achieved that would be very efficient, but not sure it can be in zero-g.

 

 

The electronics on-board satellites are often cooled by heat pipe technology. Similar to the heat pipe air cooler cooling your CPU.  Satellites use heat pipes to cool microprocessors, power convertors etc. I'm sure there are other methods I haven't heard about.

 

I don't believe many satellites have reactors at all; a few dozen are claimed, plus more in classified applications, no doubt, but most rely on photovoltaic solar panels

 

 

I didn't say anything about satellite power generation.

The rest of your post requires no response.

 

 

To sum up... The TCS [Thermal Control System] has the function to keep all the spacecraft parts within acceptable temperature ranges during all mission phases, withstanding the external environment, which can vary in a wide range as the spacecraft is exposed to deep space or to the sun and rejecting to space the internal heat dissipation of the spacecraft itself.

 

 

Paradoxically, both overheating and over cooling can be an issue in space. Satellite surfaces are submitted to large diurnal environmental fluctuations -180°C up to +150°C.

 

 

Edit: I may be correct in regrd to the need for significant insulation for satalite cryoccolers. Apparently multilayer insulation is required. But again...I'm no expert.

http://www.ruag.com/space/products/satellite-structures-mechanisms-mechanical-equipment/thermal-systems/cryogenic-insulation-coolcat/

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Nearly forgot...

 

but not sure it can be in zero-g.

 

 

Technically I think you'll find it's not zero-g, it's free fall. The satellite is still under the influence of gravity. But again, I'm no expert.

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Sorry about the mistake. I thought you were referring to on-board reactors, some of which have been flown, but of course none were fusion reactors and most are not even fission reactors.

Technically I think you'll find it's not zero-g, it's free fall. The satellite

is still under the influence of gravity. But again, I'm no expert.

I'll claim the same caveat - I'm no expert either, but I think the free-fall analogy only applies to orbiting satellites, or in the approach/descent phase of "sling-shot" manoeuvres around massive bodies. In any case, whether zero or micro-gravity is pretty much splitting hairs. I'd expect that the acceleration is so small as to make a natural circulation cooling system difficult or impossible.

I'm surprised heat pipes could be used, since they are normally only considered to be efficient in a relatively narrow temperature range. They can be designed to operate in various temperature environments, but have to be more or less customized for the thermal environment they are intended for, at the time they are constructed. The refrigerant and internal pressure are the variable design factors, but once built, they work well only for the temperature range they were designed for. I guess they must have figured out how to make them work but I would have thought that the wide range of temperatures a satellite experiences would make that a difficult application for heat pipes.

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I'll claim the same caveat - I'm no expert either, but I think the free-fall analogy only applies to orbiting satellites, or in the approach/descent phase of "sling-shot" manoeuvres around massive bodies. In any case, whether zero or micro-gravity is pretty much splitting hairs. I'd expect that the acceleration is so small as to make a natural circulation cooling system difficult or impossible.

And we are discussing "orbiting satellites". The definition of a "satellite" is anything that orbits something else. A satellite is a satellite because it IS orbiting another body. And an object following an orbital path around another body is following the gravitational curved path of the geodesic, so yes, it’s in free-fall.

I'm surprised heat pipes could be used, since they are normally only considered to be efficient in a relatively narrow temperature range. They can be designed to operate in various temperature environments, but have to be more or less customized for the thermal environment they are intended for, at the time they are constructed. The refrigerant and internal pressure are the variable design factors, but once built, they work well only for the temperature range they were designed for. I guess they must have figured out how to make them work but I would have thought that the wide range of temperatures a satellite experiences would make that a difficult application for heat pipes.

 

 

On the contrary, heat pipes have been very successful in regard to cooling satellites. In fact I believe pretty much all satellites use heat pipe cooling.

 

Satellite thermal control choices include:

Advanced solid conduction k-Core® products (an excellent backbone for both doubler and radiator assemblies)

Constant conductance heat pipes

Variable conductance heat pipes

Axially-grooved low temperature heat pipes

Copper-water heat pipes — qualified for spacecraft applications (incorporated into the Navy’s Windcat Microwave Radiometer Satellite)

Loop heat pipes — ideal for heat rejection radiator panels that are deployed only upon entering orbit. Thermacore’s loop heat pipe technology can transport and reject heat loads of more than 2,000 W

http://www.thermacore.com/applications/satellite-thermal-control.aspx

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