PC-Aero’s Elektra One

Please do not take this post wrong; I suport efforts for electric flight as the vehicle as a whole has the potential to become more efficient and potentially have the ability to become more reliable than internal combustion engines. Mind you I said potential, but as for being a green product, I think that many of these systems are getting a pass for being green without considering the entire power system.

Batteries and liquid fuels differ in that the fuel is directly converted into energy via combustion in the engine attached to the plane. This may seem like an obvious statement, but here is where the major difference is to be found. With batteries, most methods of providing power come from combustion. This may range from coal to natural gas. Yes there are other forms of power generation, but they do not tend to represent the majority of power generation, and of course there can be no agreement as to which of these methods is green (think about it nuclear is now proclaimed as a green energy source, but look at how it was viewed in the 70’s, or how hydro was stopped due to environmental concerns). To charge a battery, we must use a process that is in the efficiency range only slightly higher than a car’s ic engine, let’s say for argument that it is 50% efficient. There are now line losses in transmitting that power to the charging station. We will say that is 90% efficient, our overall system is now at 45%. We now need to convert that power from AC voltage to DC voltage to charge the batteries. Once again let’s say that this is 90% efficient, we are down to 41%. Now that the batteries are charged, and not taking into account that batteries naturally discharge if they are left to on their own, we now need to run a motor that is for the sake of the argument 90% efficient. We are down to a system that has an overall efficiency of 36% efficient, or right in the range of good combustion engine and we are still burning fuels to get the entire process done.

The gains are not to be found in the efficiency of the electric motor, but in the potential to have better aerodynamics: much lower cooling losses, better form drag due to a better cowling, and slightly improved propeller performance due to less blockage after the propeller. There are also gains to be made in the system complexity as the replaceable part count will go down (battery, charging circuit, speed controller, and motor) though some may argue that electronics only add complexity.

The only drawback that still remains is of course the weight, size, and other complications of the battery. There are still issues of the fact that the battery does not have the weight to energy level of combustible fuels, and their lifespan which will add to the over cost of the price per energy released. This combined with the need to establish a program to recover the battery to remain with the environmentally friendly mantra that we are trying to follow.

To sum it all up, I am happy to see the advancements in the electric power field. I remember when electric powered model airplanes were a joke, and now they are more of the norm than the exception. I do think that there are great potentials to be achieved with electric power, but to call it a green technology is somewhat of a naïve viewpoint. The vehicle itself does not produce emissions, but to charge the battery there are emissions produced. If we can agree to call nuclear a green energy source, and replace the power generation with it and systems such as solar, geothermal and a few other debated green energy sources, then and only then can we say that electric powered vehicles are part of a much larger system that reduces emissions and contribute to what have been established as green goals.

Adam

Adam :
You wrote : “The (electric) vehicle itself does not produce emissions”…
That is true about flying, but this vehicle has first to be built . If this aircraft needs to be totally carbon fiber built for saving weight and performances reasons, there is a huge amount of energy (that is to say emissions) included in the airframe at the start, anyway the aircraft flies or not. Maybe the same for batteries; furthermore their reduced life time darkens the green count.

(Editor’s note: Paul Lucas, with Serge Pennec, designed and built Dieselis, a light aircraft that flies behind an Opel diesel engine. Their lightweight wooden construction and home-made reduction gear system contributed to the good performance of the plane and its low cost – about $7,000. One might quibble, though with M. Lucas’s view of carbon fiber and battery issues. Carbon fiber can be recycled, as can lithium and other materials in modern batteries. How much this will contribute to long-term and overall real costs is still to be determined, and should be part of an ongoing investigation and dialogue.)

Paul,

Perhaps I am reading your comment incorrectly (the unfortunate byproduct of the internet) but you actually seem to be adding even more to the argument that I was trying to put forth, which was two fold: first everything needs to be looked at as a system, and not from a “marketing” perspective, and second that no one can even agree what “green” means and consequently has only become a term for marketing and politicians.

So as to be understood, I am not what you would call an environmentalist, nor a “green” advocate. I am an engineer. As an engineer one tries to make things better and do it more efficiently as this leads to better performance. There are obviously differing areas in which one might try to improve a concept, and in the end everything is a compromise. I find it unfortunate that this world has become so polarized to not recognize this plain fact that there is still no such thing as a free lunch.

That being said, I am also not an advocate of being dirty and wasteful for the sake of doing so. There is a complex balance that needs to be maintained as energy went into past generation systems to have them produced, and to throw them away for the sake of getting something that is more efficient (energy efficiency) may in the end cause more money to be spent and the same amount of overall energy to be consumed for both systems (the original and the replacement) as for if you were to have kept the original system longer and replaced it at its end of life or close to that point.

To deal with your argument more specifically of building materials, this is a given equal trade. You have plane A, and plane B. Both are built of some material which require the consumption of resources to manufacture. What are the actual amounts of resources for a particular amount of material compared to the operating resources of the product life cycle? I do not know, but I would be willing to bet that the resource cost of the materials are negligible compared to the operating resources. I freely admit that this is a semieducated guess, please do not quote it as fact, and feel free to prove or disprove it.

Adam

Bill,

I am not sure if this post will get posted, I still have one more awaiting moderation, but as an engineer I feel that we cannot pick and choose how we evaluate new proposals in the manner that you propose. It is important to analyze a situation in which the most common usage method should be looked at first, and then at the minor uses later. The reason being is that you cannot control the other variables with confidence.

The standard user today would plug the electric battery into a wall charger as this is the cheapest (initial investment) method to get the desired result. Because of this we need to, as engineers, stop looking with tunnel vision to achieve great results. We tend to have the if we build it they will come syndrome. Unfortunately we build only a small portion of the puzzle and the rest of the pieces never get implemented.

As for solar, is it possible to do? Yes. Is the cost of installing such a system high? Yes, perhaps as much as the aircraft. Are there limitations? Yes, the rate of charge is low, cloudy areas, night times, and what happens when I am flying cross country? The cross country limitation alone could hamper the effort as charging a battery this large will take hours even on a “standard” wall connection, let alone solar power. If there was a solar installation that could provide the voltage and amperage requirements, it would have to be large and therefore more likely to have to be funded at government level for initial infrastructure establishment and growth.

To sum this all up, we need to take a broader view of how our new and exciting technology fits in as a system to truly understand if we are making an incremental improvement or a step change. We must be realistic about its method of use and not just give the most optimistic case. Remember the masses will not use the most optimistic engineering case unless it is somehow optimistic for them (read here, costs less). Lastly, and unfortunately, unless we can overcome regulatory hurdles and provide a true product that is as safe or safer than the product it is intended to replace this will remain in prototype stage. Do I think that is is possible to have adoption of general aviation electric aircraft, yes. Do I think that it will be common place in the next 20 years, I do not. Do I think that it can become accepted and eventually get certification through the FAA yes, though at great expense to the pioneers.

Adam

I’ve been driving electric autos to work for over 10 years. My wife also drives electric to work daily. Yes the autos both run highway speeds. Everyone is so focused on “it won’t work” that the progress is slowed. First coal fired is still cleaner than ICE power. Second, I have a solar/wind array where I get the power for the cars. An electric powered “Sunday flyer” could be powered by electric which one gets from their own array. Charging is slow but if you only fly like most private pilots maybe twice a month or once a week, the battery is charged.
Stop thinking like Exxon/Mobil, BP, and Shell want you to think.

(Editor’s Note: one of the things that retards progress is sticking with the status quo. We each can empower (!) ourselves, as Mr. Brecher has done, and achieve a future that looks the way we want it to.)

Appreciating the time and effort you put into your site and in depth information you present. It’s nice to come across a blog every once in a while that isn’t the same old rehashed information. Wonderful read! I’ve bookmarked your site and I’m including your RSS feeds to my Google account.

(Editor’s Note: Thank you!)

I’m very late to this discussion (too late?) Anyway, I have been working with energy production on an R&D level my entire adult life, and I have been flying and building airplanes (RC and experimental) even longer. I am still doing both.

Electric airplanes will be the next revolution in aerospace technology, but not for any of the reasons you propose. The reason you propose is the political push, but ultimately people themselves will eventually *choose* to go electric. The reasons are less noise, simple construction overall (less vibration), no fumes, better performance overall, virtually no maintenance, etc. The electric choice is simply a much better choice overall for *practical* as well as performance reasons. What is holding this revolution back is of course battery technology. With current battery technology it is impossible to achieve the usual mission the typical GA airplane is filling – endurance mostly, but also the fact that charging takes too much time. Cost of battery packages is also an issue, but mostly due to lack of standardization: it is not a technological problem.

Let’s look at RC airplanes. How are the endurance and charging problem solved? Endurance is not an issue today, the current battery technology is good enough for a typical RC flight. The charging problem still exists, and the solution is replaceable battery packages. When one is used, one or two others are charging, or they are pre-charged. And of course, standardization of batteries, chargers, contactors, engine technology, engine controllers etc. has made all this affordable for everyone.

At exactly what level is the electrical choice today, and is this level good enough for *some* typical GA missions? Look at the Tesla sport car, that is the current level regarding performance. This level of performance can today, with virtually no modifications, be used in aerobatics (short flights, lots of power, more than current level). It can, and is, used for gliders replacing two stroke engines to sustain and for self launching. It can be used for glider tugs, and achieve MUCH better performance than current alternatives. It can be used for trainer aircraft (short duration of flight close to the airport). The reason the electrical choice isn’t utilized in all these areas are purely practical ones, there are *no* technological obstacles there. The practical problems will only be solved when people start solving them, and that is only done by doing. When doing, an industry will automatically emerge, standardization will emerge, with good solutions for battery packages, charging, easy replacement of battery packages.

PC Aero is one pioneer in this area, and more are coming. Is it “green”? My answer is undoubtedly YES. It is “greener” than any fossil fuel alternative today, and will only become even “greener” in the future when solar power grows on an international level and battery technology gets better. A political push is good, necessary even, but already today the technology is developed to such a degree that several areas of GA will achieve much better performance by going electric than they are doing today. It is the practicalities and lack of industry that is holding it back, we only need more pioneers: more people have to start doing.

(Editor’s Note: We are unaware of “pushing” a political solution to battery or other issues involving electric or green flight. Most of the blog extols the efforts of individuals and groups – quite often on their own dime – who struggle daily with making batteries more powerful, longer lasting, and more reliable; or who put untold dollars and euros into developing aircraft that may or may not find a market willing to pick up the early adapter high costs. Note the corpses of electric automotive companies strewn along the roadway, despite many having gained government funding, both here and in Europe.

Many are achieving success within the limitations you note. Anne Lavrand has helped power several record-setting airplanes with simple brushed motors, for instance, and Eric Raymond crossed the U. S. on old-school solar power 23 years before Solar Impulse – with lots of big money backers – began its attempt. The garage inventors are doing what they can, and combining their efforts and skills with the brain trusts available will give us some extraordinary breakthroughs.)