#e-aircraft

[flyingprivate]

“Next Gen” Electric Aircraft 

Courtesy: Airbus

[newluddite]

Electric Aircraft Races

Electric power is a big thing in small aircraft as in tiny.  Radio Controlled models and of course drones do well with small powerful (relatively) motors and batteries.  Scaling up to actually carry humans is something else entirely.  The scaling effect is a very real problem.  If something doubles in all dimension it is 8 times as heavy.  An aircraft with a 20 ft wingspan will weigh 64 times one with a 5 ft wingspan if in proportion.

I have noted before that a small company in Slovenia has had an electric plane on the market for a few years.  It can fly for about 90 minutes then can be recharged by swapping out the battery pack.  In the news from the Dubai Airshow is a small racing plane that has electric power and is as fast as IC racing planes.  Airbus is involved somehow but I wonder how they can justify it.  Also it must be embarrassing for the largest aerospace company in the world to be shown up by a tiny eastern European operation.

Racing is a great place to develop and prove technology.  Seat belts and disk brakes came from racing.  High performance engines and super efficient hybrids also were helped along by competition.  Thing is this cutting edge electric racing aircraft can only fly for about 8 minutes.  That is take off, make a few laps of the circuit, then run for home. That is worse than pathetic.  Useless is another word that is appropriate.

There is an all electric racing program for cars.  It is kinda spooky that the cars run so fast and the only sound is a mild whine and wind noise.  They are fast, but can only run for about 20 minutes.  To make races interesting they stop in the middle and switch to new fully charged cars.  They also avoid venues near races with “real” cars.

Race cars can be heavier than planes and therefore carry more batteries.  Planes are very sensitive to weight. Batteries are heavy.  Even the best super high tech batteries are heavy.  To equal the performance of liquid fuels batteries have to get something like 30 times better on a weight basis.  That is far harder than “one more breakthrough.”

This plane has wings and needs a very skilled pilot and an airport.  It is not a technology that will contribute to person flying cars with hovering and vertical takeoff.

The infamous Ehang 184 has carried humans in test flights, but it too can only fly a few minutes.  I could get to work in one if I had two, so when I got to work that one has 24 hours to recharge while I took the 2nd one home.  I can drive to work in heavy traffic in 25 minutes.  Just one more breakthrough.  The cost would literally buy me a lifetime supply of petroleum fuel.  Also I could only use it in good weather.

It is unfair to compare cars and planes.  Every gram of weight is important in aircraft.  Cars can carry heavy loads.  Electric cars and Hybrids are very heavy.  A quarter ton of batteries is manageable with wheels.  Cars gain huge range from regenerative braking.  When you accelerate you convert potential energy to kinetic energy.  When an e-car brakes a large proportion of that can be recovered and put back in the battery.  A similar effect helps in going up then down hills.  The energy you have is used very efficiently.  A typical electric motor is also three times more efficient than a really good IC engine.

A car can carry batteries with 1/4 the power of 60 lbs of fuel in 500 lbs of batteries and perform very well for city driving.  That fuel will also carry the IC car double the distance. Range is not that important in commuting.

I am not against E-cars.  It is very likely I will get one once the cost of a used one comes down enough.  I like the concept and for commuting it is a very good solution. Cars are not planes. You cannot use regenerative braking in planes.  That is a huge loss in terms of usable energy.

In summary I am not holding my breath.  Actually it would make more sense to start working on straight anti-gravity.  It would be far more useful and probably cheaper even if impossible.

[airinsight]

“CityAirbus” demonstrator achieves Iron-Bird ‘Power On’

Airbus announced, in time for the Singapore show, that its “CityAirbus” electrical urban-air-mobility demonstrator programme reached an important milestone: the completion and “power on” of the “iron bird” ground test facility in Taufkirchen, Germany.

This enables the verification of the entire electric propulsion system of CityAirbus, developed by Airbus’ E-Aircraft Systems unit. After being…

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