New Electric Motor That’s Super Light and Powerful for Electric Airplanes | Hacker News Reader

New Electric Motor That’s Super Light and Powerful for Electric Airplanes

transportevolved.com

129 pointsdavidst104 comments

A lighter engine certainly doesn't hurt, but it's really the batteries that are an issue. The other item often overlooked on the battery front is that most batteries hate the cold. Take your iPhone out on a 20F day and see how long that 100% charge lasts! (Spoiler alert, likely a few minutes).

As you go up in the atmosphere things start to get really cold. Until the weight and temperature issues with batteries can be address electrical aviation will be mostly a concept on paper.

Waste heat can help keep the batteries warm. For example, Teslas have a battery heater which really eats power when you start out in the cold, but after you're cruising it reaches a steady state. Range still suffers, but at that point it's cabin heating and air resistance. Assuming the batteries are in the wings, you'll probably have voids between the batteries and the skin (since batteries don't have very a aerodynamic shape) which could be insulated without too much of a weight penalty.

Battery weight is a huge problem, of course. A Tesla battery pack is 1200 pounds. That's more than many light airplanes weigh total! The motor and inverter are only about 350 pounds, by comparison.

It looked like the battery pack was just behind the motor, in the nose, on the test plane. Easy to let the heat just flow back from the motor.

Of course, it's a small battery pack.

FYI: I've ridden a few regional flights from Sacramento to the bay that are only about 15 minutes in the air, so the battery life might be as huge an issue as it's made out to be. Use electric for regional hops, and jets for longer "traditional" flights.

Some flights may only be 15 minutes in the air, but that doesn't reflect the fuel requirements for aircraft. I believe you're required to keep something like 30-45 minutes worth of fuel beyond what you need to get to your destination.

I've noticed that people who work on electric aircraft express some annoyance with this.

That's right. It's 30 minutes for VFR, 45 for IFR. Minimum. Nearly all commercial flights are IFR.

Thanks for pointing that out, you two. Still, it's probably doable to increase the battery capacity a bit to get cruising time (vs high powered climbing time).

Not there yet, but probably within spitting distance of a few of the use cases on the edges.

Unfortunately, no. For IFR you have to be able to fly an approach at the primary airport, then fly to the alternate airport, do an approach there, and then fly an additional 45 minutes. After each approach you have to be able to fly the missed approach procedure, which necessarily involves climbing. Just being able to cruise for 45 minutes is not enough.

https://www.law.cornell.edu/cfr/text/14/91.167

> I believe you're required to keep something like 30-45 minutes worth of fuel beyond what you need to get to your destination.

> I've noticed that people who work on electric aircraft express some annoyance with this.

As someone who was just on a plane who was recently on a plane that was diverted to another airport due to dangerously bad weather, I'm glad those requirements are there. There's all kind of things that can go wrong that could delay a landing for a half hour or more.

The motor won't produce much heat, since it's really efficient, but that will definitely help.

And yes, there are certainly use cases which come up as the technology improves. Actually, the airplane I want to buy when I win the lottery is electric: the Antares 20E. It's an electric self-launching glider, so it really just needs enough to get airborne and to a decent altitude, then you use the weather to stay up. Short hops like you describe would work too.

It's much like cars. The Nissan LEAF was useless for driving across the country but great if you just need to get around the city, and then better technology and range increase the number of scenarios where the cars are useful.

> Take your iPhone out on a 20F day and see how long that 100% charge lasts! (Spoiler alert, likely a few minutes).

It's true that Lithium Ion batteries lose their charge in cold temperatures, but not that quickly. An iPhone in 20F will still hold charge for several hours. (And of course, under normal operating conditions the iPhone will be close to a warm human regardless of ambient temperature, so they rarely get that cold.)

Grandparent is right IME

HN chain from when it happened to me - https://news.ycombinator.com/item?id=10939215

Your account sounds different from what GP describes (ie. descending from full charge in a few minutes, without any activity).

I live an a region that regularly stays below 0F for months on end and have never seen or experienced such extremely accelerated loss of charge. However, I have certainly seen phones lose charge more quickly once they get below 50% or so--I never correlated that with the cold, but maybe there is a connection.

I wonder if we have different phones? Mine is a regular iPhone 6

Theses reports seem pretty anecdotal. Is there some hard evidence or an official spec? Seems like a bunch of people with glitchy phones or batteries blaming the weather.

It has only happened once, but I doubt the phone is faulty - it instantly went from a charge in the 40% range to a 'plug in now' screen, eventually returning to normal with the same amount of charge once I got out of the cold.

Could be that different phone models behave differently in low temperatures?

iPhones have a single Li-ion cell and the phone itself sips power compared to an aircraft motor.

For a slightly more apt comparison-- try flying your DJI phantom on a cold winter day. It won't last long.

> As you go up in the atmosphere things start to get really cold.

Yes, but the air is also much much thinner. So it doesn't suck heat away nearly as quickly as it might at ground level. So the batteries should retain heat.

I don't see the energy-density math. Batteries in passenger planes would have to last far longer than the flight duration, at least 30minutes more to accommodate safety margins such as diversion to other landing sites. And a battery-powered plane must suffer from the fact that it hauls around dead batteries. A gas-powered plane gets lighter as it burns fuel. So, by my math, an electric passenger plane would require an energy density at least four or five times that of current battery tech. The motor isn't the issue.

I still find the same issue with cars, they have to haul around dead batteries until recharged. They just have the advantage that they cannot fall off the earth. The weight has come down a lot for both applications, the idea we need to haul over 400kg of batteries for so little range is mind boggling. Of course with increased power density comes the issue of charging it quickly and safely.

Enough tech is here to make these types of cars a viable second or third car for many people but they aren't viable replacements in general. I am still surprised the government never pushed to move all school buses to electric, they have space and spare capacity to support them and ideal spots to recharge many times a day

I would assume a bunch of the battery usage would be from take off. You'd think they could design a system like a rocket launch with a "staged" plane launch, where the batteries used for take off would then be jettisoned to land safely back at the airport for re-use.

A while ago I read a proposal by airbus for an electric airliner. They speculated that batteries could be recharged on the way back down from altitude. If you want to recover energy, you;ll need those empty batteries.

You go higher so you can go faster. The next heat exchange with the thinner air remains about constant.

If the batteries were exposed. But I assume they will be behind some cover, in relatively stable air. If the worry is that the batteries will get too cold, keeping them out of the wind is easy. (also, more aerodynamic)

I'm curious if a heater coil gives better battery life or worse battery life in cold environments. Also, better batteries has been an issue forever. Electric cars were invented alongside the combustion car, but they didn't have good batteries, and died because of it.

Heater coil gives way worse battery life, but can still be useful to preserve other electronics in the cold.

Assuming you start the flight from mains power it depends on volume. https://en.wikipedia.org/wiki/Gigantothermy

For a poorly insulated toy quadcopter it is a bad idea. Something, the size of a 747 might need active cooling. Between them there is a point where a little heating is probably a good idea.

If the batter is working hard delivering power, it will generate some heat on it's own.

Batteries don't like the heat either, which is why battery packs in electric vehicles have their own cooling systems, so I wonder if there is a way to design the layout and power curve of battery-motive systems to balance the two out and maintain ideal temperature.

I wonder if hydrogen and fuel cell would have the right P/W ratio to power this. Hydrogen fuel cell should work well at low temperatures.

However, first instinct is to not get into any aircraft with hydrogen on board ;)

Well, in terms of energy density, you are alright: https://en.wikipedia.org/wiki/Energy_density

... but not in terms of power/weight for the motor (or fuel cell in this case): https://en.wikipedia.org/wiki/Power-to-weight_ratio#Fuel_cel...

... You'd need about 1000lbs of weight for 200hp equivalent.

Also, I'd rather be surrounded by hydrogen than jet fuel :).

You'd think that since the article is about how this motor is a new record in power density (or rather specific power), it would include the specific power in the article somewhere. You would be wrong, but it does include the information needed to calculate it. The SP260D motor they're talking about has a specific power of 260 kW / 50 kg = 5.2 kW/kg. It's not clear if this includes the weight of the batteries or not.

The article says the usual motor for the Walter Extra 330L is 315 horsepower, which is 234 kW. The "E" in the model number "330LE" apparently refers to the electric version.

To contextualize, motor specific power is actually really important for heavier-than-air flight. The reason Leonardo's helicopter designs wouldn't work is a lack of specific power in the (human) motors he had in mind, more than any aerodynamic reason. (Sufficiently high specific powers can overcome even remarkably poor aerodynamics.) The Wright brothers' main innovations were: a workable system for steering, and a motor with sufficiently high specific power.

The bit about the motor's end shield seems to be describing topological optimization, but the description of the process is somewhat ambiguous. It would be nice to see a picture of the end shield and maybe information about how it's made.

Maybe a less clueless, though even more information-scarce, article is http://www.flyingmag.com/extra-unveils-electric-330le

Other commenters are pointing out that this won't work for long-distance flight. The Flying article I linked above says it will actually only last either 5 minutes or 15–20 minutes (it seems to contradict itself, but maybe I just don't understand it.) So it's adequate for aerobatics only. But it should be better at aerobatics than the standard engine was.

Further links from other comments: https://news.ycombinator.com/item?id=12060954 http://www.gizmag.com/siemens-world-record-electric-motor-ai... https://newshour.online/2016/07/04/world-record-electric-mot...

Speaking of helicopters and specific power and weight and all that, it seems an article of faith that eventually an electromotive tail fan will be lighter than all equivalent reliability mechanical or pneumatic systems. I mean sooner or later as magnet strengths and VFD voltages approach infinity and VFD and motor mass approach zero, at some point the rube goldberg mechanics that make the tail rotor spin will be replaced by a near weightless power cable and electric motor.

You don't need a battery to spin a tail rotor... once the main disk stops spinning there isn't much point in keeping the tail rotor spinning.

A hybrid helicopter is an interesting concept, rather than zero torque the instant the engine dies and hope for good luck WRT autorotation technique, even merely giving the pilot 15 extra seconds of battery thrust would probably save some lives.

Pneumatic hoses are pretty light too, and pneumatic motors are usually a lot lighter and more reliable than electric motors of the same power. But maybe you're saying that this is merely a function of low voltages and weak permanent magnets, and we can expect electric motors to get a lot lighter? I guess that's possible; can you point me at some exemplary modern motors?

I tried to write a thing here about the physics of the situation — saturation flux densities and layer-wound armatures and resistivities and dielectric strengths and so on — but then I realized that I don't actually understand the physics of electric motors well enough to say anything coherent. How are electric motors increasing their specific powers — is it just by higher RPMs, or is it a matter of more poles and/or better materials and geometries? What are the limiting factors?

Drexler gets into electrostatic motor scaling in Nanosystems and presumably his thesis. I have no idea about the kind of designs made today, though.

> The Wright brothers' main innovations were: a workable system for steering, and a motor with sufficiently high specific power.

And an airframe that could work with both of those. Langley, for example, had an engine that weighed about the same as the Wrights', but put out 50 horsepower to their 12. But the Aerodrome collapsed on takeoff, rendering that power useless. The Wrights had a mechanically simpler design that was strong enough to cope with aerodynamic forces.

http://www.flyingmag.com/extra-unveils-electric-330le

I am working on the up left side plane in the picture "EuroSportAircraft" it's a highly efficient aerodynamics, our electrical version manages 1 min flight time for each 1kg/2.2lb battery weight.

This article has almost nothing about the actual motor in the title except this:

"every component from previous motors was examined and optimized to lighten this motor and improve efficiency. The end-shield for the motor, for example, was analyzed using a software package that divided the component into over 100,000 elements, each of which was individually further stress-analyzed and subject to iterative improvement loops. Eventually, the custom software spat out a filigree structure that weighs 4.9kg instead of the 10.5kg from the previous design."

The rest of the article is basically fluff with no info.

Even this paragraph is just a general description of what could potentially be a FEM analysis and some optimisation algorithm associated with that. Interesting result on the other hand.

I agree, read like a press release from Siemens.

Just penciling in the math that means a quad copter is pretty straight forward with this motor. 200kg for a "megawatt" of thrust. Now all we need are batteries that are 3x as power dense as the current best of class and you'll be able to hop from home to the office in your 'quad'.

There's a startup in my area that are working on an electric helicopter: http://volocopter.com/ - they use 18 rotors, probably because bigger motors get heavy really quickly, but also for redundancy.

I believe that they use many small motors instead of a big one because quadcopter like planes are controlled by changing blade speed and that bigger blades have much more inertia which limits the speed at which the rotation can bee accelerated. Helicopters spin their blades at a constant speed and vary the angle of attack of the blades to obtain the same control which means it is less affected by inertia.

Why would you use batteries? Fuel gets lighter as you use it, and the density is already there. Automate maintenance so you can use turbines.

My guess would be electric might be simpler and easier to maintain and with electric you can charge at home.

mass per kilowatt hour. That is the magic number. While a gas turbine can be slightly over 52% efficient it weighs a lot. You can plot weight over kilowatt hours, which is useful since at small numbers of kilowatt hours batteries are a huge win, and then at some point you get a cross over where the fact that fuel is more energy dense it has compensated for the weight of the turbine and generator infrastructure.

Not my area of expertise here, but since quadcopters are all about torque, I speculate that electric motors (with their flat-ish torque curve) are much easier to design for?

I've thought the same thing, perhaps efficiencies for generating electricity for fuel engines are too low currently? Anyone have any stats?

Maintaining EVs is cheaper and easier than fuel-based vehicles.

I believe pluggable, human carrying quads have potential in couple of industries like building maintenance, firefighter ladder replacement or lift alternatives.

Problem is the power delivery, you'd need around 20kW of power. That is not available just about everywhere and requires fairly thick cable.

There's a startup called Plugless that makes wireless charging equipment for cars[1] (basically a scaled-up version of the wireless phone chargers). The current version puts out around 3.3kW continuous - not quite that 20 kW, but in the ballpark. Perhaps that technology could be developed to suit that niche.

[1]https://www.pluglesspower.com/look/?jump=tech#tech-specs

I want a cable laying snake..

I applaud Siemens for venturing outside their comfort (profit?) zone instead of just incrementally improving whatever they did for decades already (and did not sell for having a bad quarter), but they are really overdoing milking this little plane for publicity. An electric motor being lighter, per Watt, than an ICE, who would have guessed.

That being said, a hybrid setup could well be worth it, even with the abysmal specific energy density of real life batteries: keep just as much conventional engine as needed for cruise flight only and have some form of electrical assist for the few minutes of a flight that need more power than that. Battery density isn't a problem at all when you don't need endurance.

Sounds absolutely perfect idea for Eraknoplans.

https://en.wikipedia.org/wiki/Ground_effect_vehicle

Typically these vehicles have 4X as much engine power for liftoff as they need for cruising. The reason is high water resistance and then very economical flight above the water body. Lift off being cancelled due to engine malfunction is less of a problem, as the "runway" is practically endless.

For a hybrid setup, regulations will likely require that both the conventional engine and the electrical system to be powerful enough on their own to still take off if the other system fails after V1.

Still, that's massive savings over the current twinjets, which require two engines, both powerful enough to take off after a failure of the other at V1.

Sounds reasonable. But in an unlikely best case scenario, the electric part might somehow be certified for single engine reliability, capable of everything except endurance. A wave of comparatively liberal cruise engine development might then catch up with a few decades of combustion engine refinement.

Already discussed at https://news.ycombinator.com/item?id=12060954 ... Some commenters had more info on the engine on this thread.

I wouldn't think even older electric motors wouldn't work well enough in electric airplanes regarding weight and power? The weight of batteries is the biggest problem.

There was this article[0] where they explain that light electric motors allow for new interesting design (e.g. in motor placement, and number of them).

[0] http://spectrum.ieee.org/aerospace/aviation/how-i-designed-a...

Have an on board diesel generator

LOL. Technically some heavy trucks and engines, are powered by electric motor with generator. Some of the biggest trucks and tanks were electric ;-)

https://en.wikipedia.org/wiki/Diesel-electric_transmission

You would use a turbine. Like the APU in existing aircraft

Electric airplanes already exist. Obviously they're not replacing long haul airliners this year... but not every plane is meant for that sort of use.

I thought it was the battery, not the engine, that prevented long-distance flight? For energy / kilogram, lithium batteries are around 200 while gasoline is around 13,200.

Yep - and as you use up fuel, your plane gets lighter, saving more fuel the longer you fly. With batteries, you have to carry the same weight for the duration of the flight. Which actually is a huge problem, because on most airplanes maximum take-off weight is higher than maximum landing weight.

I have the stupidest idea. As energyless state fuel is released in the air, just drop 'depleted' battery modules and have them collected.

Air to air refueling where the refueling is fast charging lithium batteries and the tanker is formation of drones not KC-135 full of jet fuel.

Probably not the craziest idea ever.

While the "refueling drones" are circling overhead waiting to charge up a transport jet, may as well use them as five mile high wifi access points for internet, and divebomb amazon deliveries. I mean they're up there, may as well make use of them when they aren't charging jets.

Think of the FAA madness WRT flight plans and mandatory minimum "fuel" and alternatives/diverts. The paperwork alone for aerial refueling on plain old passenger service is likely to get weird.

Meanwhile if solar panels get cheap and durable enough, or safe enough in a crash to plow thru, charge the drones off panels laying around the airfield.

In theory you could have 100% solar powered high speed aircraft transportation using this weird system.

Note that you can cross the ocean if you have a dense enough fleet of charger drones. By dense "enough" I have no idea what to say here.

You need enough battery power to get "up there" and to cruise between drone hookups (which might only be a couple seconds if the drone comes along with you, or if you have dual charging ports I guess that means zero...)

Note that every airframe full of people requiring 2 or 3 smaller airframes full of batteries will be an interesting capital cost to work around.

Another stupid idea: use aircraft catapults[1] to reduce the onboard energy requirements. Takeoff seems to be the most energy demanding stage of the flight.

Obviously a drawback is that existing airfields' or airports' runways would have to be retrofitted, but if the fuel and maintenance savings were enough, it might make sense.

[1] used on aircraft carriers: https://en.wikipedia.org/wiki/Aircraft_catapult

A cable winch like they use with sailplanes would work really well for this.

There's research going on about that [1], in fact going a step farther by removing the entire undercarriage of the plane. It's safer too -- partially extended landing gear is more dangerous than belly landing because struts and hydraulic systems are a lot more fragile than solid ribs of metal.

[1] https://en.wikipedia.org/wiki/Ground_carriage

Huh...that's actually a great idea. I never thought about it for commercial liners.

I'm sure Boeing or Airbus could create prototype liners and only have a few airports with catapults built into the airstrips. You could save a considerable amount of energy if it's designed correctly. Plus airplane tires have to be replaced very frequently. It could reduce takeoff wear as well.

You just need to carry energy into the airplane, with coils for example. No need for a catapult.

The catapult is a proven technology for aircraft though, with decades of development.

Or with a reusable launcher. Somebody get Elon on the line.

Better yet, design the battery so that air forms one side of the chemical reaction, with waste products that can be dumped overboard. Oh, wait!

(I'm making a dumb reference to ICE engines here, but actual batteries where air participates in the reaction are a promising area of research that could greatly improve battery energy density.)

Yes, lithium-air batteries have some promise. They approach gasoline energy/weight by better than half as good. So that's a possibility.

> batteries where air participates in the reaction

Wouldn't that just be a fuel cell?

Or a combustion engine, yes. That's the joke.

Here's a riff on that idea.. Have midair recharging drones fly up to meet the plane along its route. Just like the military uses to extend range, except small and automated.

still the energy/weight ratio is > 60 times worse than gasoline. If you're not going to recharge them, then there's no remaining advantage to batteries

Mechanical simplicity. If your going to use fly by wire it's nice to have stored power to land without losing control in the event of total loss of fuel or massive mechanical failure. Though this is something like 1/10,000th of total energy used in flight it's really important.

Collect, centralize, recharge, reuse. Maybe have a solarimpulse battery carrier to distribute them while flying.

Unless you use a hybrid approach, like a super efficient turbine generator + solar cells, so your battery doesn't need to be nearly as big.

I am not seeing how a jet turbofan is going to be less efficient than a turbine engine driving a generator driving an electric motor driving a propeller or fan.

I don't think there's enough surface area on an airplane to gather significant solar power. And that doesn't help at night or in clouds.

Jet turbofans have an efficiency curve related to the velocity of the aircraft. They are least efficient when the aircraft is stationary, and most efficient when the aircraft is moving at the same velocity as the exhaust.

A jet turbine generator can run at near-constant efficiency.

Or using diesel electric hybrids. That's how train engines work. They're still way more efficient that using combustibles directly because you can run at lower RPMs and buffer the energy (trains run at like 1k ~ 2k RPM).

Solar powered recon UAV with near unlimited flight time could be an application

Just combine some lighter-than-air structure with a UAV to achieve really great energy efficiency , and put solar panels on it. It would probably be possible in no-wind conditions to stay at the same point while charging the batteries.

Nothing at all about reliability, which is going to be the biggest factor the aerospace industry will be considering about this. You can sacrifice reliability for extreme power-to-weight ratio, as evidenced by things like Top Fuel dragsters and even the electric motors in RC planes are optimised more for power than longevity.

better articles

WORLD-RECORD ELECTRIC MOTOR MAKES FIRST FLIGHT

https://newshour.online/2016/07/04/world-record-electric-mot...

Siemens' world-record electric aircraft motor punches above its weight

http://www.gizmag.com/siemens-world-record-electric-motor-ai...

It seems that this motor's power-to-weight ratio advantage applies just as well to ground vehicles. Are there reasons why that isn't the case? I.e. is this approach somehow specific to heavier-than-air engines? (Also, speaking not necessarily to using this specific motor, but rather applying Siemens' cited optimization techniques for ground applications.)

The most recent episode of Fully Charged [1] looked at a 100% electric racing plane currently in development that uses two electric motors to drive two counter rotating propellers at the front of the aircraft.

[1] https://www.youtube.com/watch?v=Xe1g1JrRRkY

the use case for this aircraft is to fly 20 minutes maximum so current battery technology power to weight is enough.

This should be interesting for solar-powered remote-controlled aircraft, where battery weight is less of a concern.

To what size of aircraft can a motor like this scale? Or perhaps more importantly, motor + batteries? To put it another way, is this technology likely to scale to an aircraft transporting 4 or more people anytime soon?

Airbus are planning a 100 seater aircraft by around 2030.

It's all about the batteries. That's what's holding us back

Electric engines doesn't necessarily mean batteries. Consider micro-turbogenerators. http://dukespace.lib.duke.edu/dspace/bitstream/handle/10161/... As others mentioned, fuel has the advantage of getting lighter over travel time. Also, electric motor planes should be wrapped with solar cells.

Solar cells add weight. As an energy source its hard to quantify them since they never run out, and weight the same the whole trip. Maybe more like batteries. Anyway energy/kilo is probably pretty bad. So for any finite trip, leave off the solar cells and use gasoline.

It's easy to quantify solar cells on an airplane, just look at power consumed by propulsion and compare to power generated by the cells. The result is that the power generated is pretty much useless and doesn't even justify the weight of the solar cells, unless you design a plane to be extremely light and with nearly no payload, a la Solar Impulse.

Solar could be good for drones that stay almost permanently airborne and just need to carry some electronics, but it's pretty much useless for transportation. If you must use electricity there, you'd want to use batteries on the plane, and keep your solar panels on the ground.

Solar is bad for any aircraft that needs to change altitude rapidly, or contend with weather. The best way to transport passengers on a solar-powered aircraft would probably be to have a very large solar powered plane that remains airborne for months at a time, flying above the clouds, with smaller airplanes that shuttle passengers between it and airports.

Of course with that you have to deal with the issues of rendezvous of two flying aircraft, energy storage through the night, and pressurization of a large space. But it would avoid many of the inherent issues in solar powered aircraft.

But for the specific case you're discarding here - a solar-powered camera drone - doesn't this new motor provide a serious improvement?

Low-cost solar-powered drones could be a wonderful tool for aerial cameras.

I'm sure it'll help, but the fundamental problem with solar powered aircraft is that one pound of solar panel can lift barely more than one pound. That means saving weight on the motor can cut out a lot of solar panels, of course, but it also means you still need a ton of solar panels just to lift the structure of the aircraft and the payload.

I don't think we'll see cheap solar drones anytime soon. Current solar aircraft need to be gigantic and fly extremely slowly. Small drones typically want to be quadcopters, which are inherently inefficient, but have other nice properties. If you want a solar-powered small drone, make a stationary solar array, give the drone a swappable battery pack, and charge batteries with the stationary array while different batteries are powering the drone.

I'm starting to think good VR might do more to kill hydrocarbon consumption than electric vehicles. So many examples where moving meatbags around could be avoided altogether.

This has been discussed here in depth: http://www.antipope.org/charlie/blog-static/2016/06/why-shou... (see the comments not just the main blog entry)

As we approach the 200th anniversary of Faraday's 1821 invention of the electric motor, I am impressed we are wringing out improvements.

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