Blah blah blah. No way you fly that thing in Fla.

Nice perspective on electric power Adam. I agree wholeheartedly. The naysayers never even get off the ground though. And you gotta start somewhere.

In terms of batteries, we are rapidly approaching the theoretical limits of most of the explored chemistry. Do not expect much improvement from the current direction.
Instead, energy storage for higher density will have to take a new directions. A few examples:
-- Electrolytic capacitor
-- Superconducting magnetic energy storage
-- Fuel Cells

The point is you will need a radical change in technology. I personally think it will happen in the next five years. We already have hydrogen fuel cells now, zinc Electrolytic capacitor, and even commercially available SEMS.
Will they be on planes like the Bonanza or Cirrus, no. The first planes are going to be slow, low powered, Sunday flyers and training airplanes.

Tim

No it does not. Your plane has about 700hp/engine, that's about 500Kw/per side. So maybe a 1MW in total.

The swiss are going to try and fly a solar powered aircraft around the world, They have already flown a prototype across the US last year. I saw that plane first hand in Stl when they stopped for crew rest and publicity. The plane wing simply has a huge surface area. They also had solar cells on the tail. While it proves the tech there is a long way to go till it works for GA.
Here is a link to their web site:www.facebook.com/solarimpulse

The Solar Impulse project is interesting. The goal of being able to recharge enough during daylight to fly at night is challenging.

I think people need to keep in mind that they have only 40 HP total on the airplane, which weighs 4,400 pounds. Over 100 pounds per HP power loading.

During daylight hours, they have a 45 kw solar array. They store energy in both the batteries AND altitude. During the night, they lose both altitude and charge.

This is one project that would be better as an unmanned flight. The extra weight of the human and all the support stuff he requires is burdening the project. The plane is flown by automation most of the time anyway. They could save many hundreds of pounds this way and make it safer.

Official web site:

http://www.solarimpulse.com/en

Mike C.

I apologize for my overly shrill and aggressive post earlier. I had a bad day.

I find myself agreeing with both democrats and republicans on different subjects. Don't want this to be political. But my remarks was an observation I've had since moving to America many years ago: that the side most in favor of freedom, capitalism and entrepreneurial spirit is most often the one who is against changing the status quo. Hence the Fox News comment. As far as I know, the only legislation that have blocked the direct sales of Tesla to customers have been Republican led. I find this very strange, and it makes me understand the US political system even less. Shouldn't it be the Democrats who are for protectionist laws? Just seems un-American to do so.

As for how quick it will all be electrified, one has to make a distinction:

1. How long before the prime mover is electric?
2. How long before the prime mover is electric and also purely run from stored electricity?

Number one is the one I was talking about. I'll take a $1000 bet right here and now with anyone who wagers, that the prime mover (not the electricity storage) will be electric in 90% of the cars in 15 years. Of this I'm certain. They will all be fuel cell, hybrids, or battery powered then. Or put another way, the thing driving it forward will be an electric motor regardless of how it's powered.

Number two is harder. I happen to think that pure battery powered vehicles are not much further away than that, even with current battery capacities. But I'm not willing to take a bet quite yet. My guess 20+ years. The last to go will be heavy ground transportation.

"We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run." - Roy Amara

Yes, you are correct. But, you're carrying around fuel that could power 4MW had there been no losses, but you only get 1MW out of it as the rest is wasted. It just happens that today there is no power source that can match that. But that's a tremendous waste and very inefficient. So a battery only needs to reach a quarter of that capacity before it will eat its lunch. And when you take into account the fact that electric motors are much lighter than turboprops, you might just need a fifth or a sixth of the power of jet fuel. That's not around the corner, but it's not out of the realm of the possible by any means either. I can see a battery/capacitor/whatever reach 2400Kw/kg in my lifetime.

I'll take that bet as stated, and you're almost sure to lose as stated.

"90% of cars in 15 years" is very, very different from "90% of new cars sold in the year 15 years from now". I still doubt you'll win the second, but I'm damned sure you won't win the first...

I'll take that bet as stated, and you're almost sure to lose as stated.

"90% of cars in 15 years" is very, very different from "90% of new cars sold in the year 15 years from now". I still doubt you'll win the second, but I'm damned sure you won't win the first...

I will take that bet. I think electric motors definitely will advance and be more common, but the proven and reliable gasoline engine will be primary for a long time. Advancements in transmissions, VVT, direct injection, etc. have enabled larger SUVs to get 30+MPG and many cars will be doing 50+ MPG shortly. These cars can be produced for less money than complicated electric/fuel cell/whatever hybrids.

Some of these new 9-speed transmissions are amazing and Nissan does well with the CVT transmission. My son's Altima is averaging 40 MPG and it is 10x the car a Prius is that only gets 45 MPG average.

Not quite true....10hp/kg is about 4.6hp/lb. Take the F135 engine, it has a thrust to weight ratio of greater than 11:1 http://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135

Ok, that is thrust and not power. 1 lb thrust at 375mph is 1 hp. The higher the speed, the more hp per lb thrust.

And there is the GE T700 turboshaft with about 4.5 hp/lb. It is not state of the art even. http://en.wikipedia.org/wiki/General_Electric_T700

1MW, times 3.7 hours (of endurance), is 3.7MWh.

366 gallons of Jet-A is 13,285 KWH (kilowatt hours) of total energy (43 MJ/kg).

When I burn it in my engine, I get 3,852 KWH of useful energy (29% efficiency).

My *useful* (out the output shaft) energy storage capacity is 3,460 WH/kg considering the fuel alone. Adding in the engines and misc stuff that go with them, the system energy density is 2,500 WH/kg. This is factor of 10 or so from what can be achieved today.


It is very inefficient to carry heavy batteries. Despite the 29% efficiency of energy conversion, that overall system is still more efficient than batteries due to lighter weight.


No, to be equivalent, assuming a motor of 93% efficient, the battery would have to be 3,720 WH/kg to have the same energy density. The best batteries commercially available are a factor of 15 away from that.


You forget that a turboprop get LIGHTER as it flies, the battery airplane DOESN'T. The weight of my turboprop engines is burned off in the first hour or so of flight, then I'm lighter the remaining 3 hours.

In other words, the lighter motors don't make up for the fact batteries are weight all the time. You should penalize the electric airplane MORE for that fact. In fact, due to lower landing weights, the battery airplane is payload limited more than the fuel airplane.


2400 KW/kg is a power density, and there's nothing outside nuclear power that can deliver 2.4 megawatts from a 1 kg object.

I presume you mean an energy density of 2400 WH/kg, about a factor of 10 away from present day commercial battery technology.

I predict with great assurance that you will not see that in your lifetime and it may actually be chemically impossible.

If it does come to pass, then I agree it will be revolutionary, it will affect everything in life, a radical transformation of our society. Everything that is battery powered would be able to run 10 times as long as it does now.

No matter how compelling the outcome would be, that doesn't make the chemistry any easier to do.

Mike C.

Adam, look, I WISH we could use electricity to power the things that run on gasoline, legitimately. The issue isn't that anyone is against it, it's that it's not legitimate.

The solar powered plane that was spoken about earlier uses a 45 KW array.
Sir, that is gargantuan. AND it's "leading edge of technology", too. So are the batteries in it.

That being said, seriously, if it takes a whopping 45 KW array to make a plane fly, at extreme wing loading; how in the world could this power, (now) be used to run an actual, real, working plane?

It can't.

Now MAYBE at some point the technology just makes vast, quantum leaps forward, and I hope it does, but the truth is that to make REAL horsepower, the very best available energy source is still gasoline. Monster amount of actual power in every gallon, safe, transportable & plentiful.

I always thought a sailboat with a solar deck and sail would be a good idea. Electric power and the wind.