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  #11  
Old 01-22-2018, 03:31 PM
Paul K Paul K is offline
 
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Location: Comstock Park, MI
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A agree with everything said but just the fact that we are talking about it here is exciting! Shows there are a lot of people thinking about it.
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Last edited by Paul K : 01-22-2018 at 03:42 PM.
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  #12  
Old 01-22-2018, 03:55 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
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Default Not so bad...

Quote:
Originally Posted by Aluminum View Post
For every pound of gasoline, Mr. Lycoming burns about fourteen pounds of air (cue in LOP crowd in three..two..one..). That means you don't have to lift 93% of your airplane's chemical fuel, or some 3600 lbs of batteries given any possible...
Actually, for every pound of gas Mr. Lycoming burns 3 pounds of oxygen. All the rest of the air just passes thru. So you carry 25% of the fuel. Since a gas engine is a heat engine, itís only 40% or so efficient, while electric motors approach 100%. So Lycoming still wins but not as overwhelmingly - if electric storage weight can be brought down, it looks feasible. Thatís a big Ďifí.
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  #13  
Old 01-22-2018, 04:02 PM
rv7charlie rv7charlie is offline
 
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I wish I had a dime for every time 'never' was disproved.........

Last edited by rv7charlie : 01-22-2018 at 04:04 PM.
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  #14  
Old 01-22-2018, 04:05 PM
molson309 molson309 is offline
 
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Let's say that battery technology advances to the point where there's enough energy in the batteries to give the airplane comparable speed and range to a IC powered one.

What I worry about is what happens if all that energy decides to discharge in a short period of time? Remember gasoline needs oxygen to produce energy, so gas in the tank can't explode unless it's vaporized with the right percentage of oxygen. High density energy stored in a battery doesn't have that limitation and given the right (wrong?) circumstances can discharge very quickly indeed.

We've already seen the small scale example of this when LI-ion batteries decide to violently discharge.

You'd be flying around with the equivalent of many pounds of high explosive.

So not only does the energy density of batteries have to substantially improve, but the proven safety as well.

It will be a long time coming I think.
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  #15  
Old 01-22-2018, 04:05 PM
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FasGlas FasGlas is offline
 
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Here's something to add to this: http://www.quadcitiesbusinessnews.co...osed-prescott/
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  #16  
Old 01-22-2018, 04:25 PM
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DaleB DaleB is offline
 
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Hey, in the 70s and 80s we thought electric powered cars were impossible too. If you'd described the current crop of batteries back then you'd have been regarded as a crackpot. My cell phone has more processing power, memory and storage than the first several mainframe computers I worked on - heck, the Raspberry Pi I have sitting here on my desk does. There's a good chance my microwave oven does, too. Technology marches on, and we figure out new ways of doing things that would look like magic or sci-fi to our 20-year-past selves.

I don't expect to see viable electric powered airplanes any time soon... but I do expect to see them.
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  #17  
Old 01-22-2018, 06:41 PM
Strappe Strappe is offline
 
Join Date: Jul 2017
Location: Omaha, NE
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I don't think anyone would propose using lots of exploding Li-ion batteries. Lithium iron phosphate, on the other hand, has a good safety record so far.

We know of way too many innovative companies out there working on electric and various hybrid vehicles to think progress won't begin to accelerate rapidly.

Most of my trips in a plane are easily within current considerations of battery range - many are hour-long, low altitude cruises. For fun. For relaxing.

7Ĺ minutes? That might miss the point that no one would try to power that size engine with that little battery capacity.

Seems to me that the homebuilding community is almost entirely responsible for many of the advances in light aircraft design and innovation. Isn't that the main force that move us out of the 1940s or 50s in materials as well?
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  #18  
Old 01-22-2018, 06:42 PM
Rallylancer122 Rallylancer122 is offline
 
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Location: Oconto, WI
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When I looked into it the battery density just wasn't there yet for a traditional plane. That's why the few electric airplanes you do see are basically motor gliders. That being said, with some bespoke engineering it's getting close. Check out the Bye Sunflyer.

Some companies aren't waiting around for batteries and are going hybrid electric. Combustion engine drives a generator which in turn drives the electric motor. This sounds inefficient until you look at vertical lift. Getting rid of gearboxes, transmissions, and complicated mechanical flight controls makes it a lot more compelling. Super light motors are everywhere. Now, if I could just figure out where to get a super light generator....?

DEM
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  #19  
Old 01-22-2018, 08:18 PM
Aluminum Aluminum is offline
 
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Location: San Jose, CA
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Quote:
Originally Posted by BobTurner View Post
Actually, for every pound of gas Mr. Lycoming burns 3 pounds of oxygen. All the rest of the air just passes thru. So you carry 25% of the fuel. Since a gas engine is a heat engine, itís only 40% or so efficient, while electric motors approach 100%. So Lycoming still wins but not as overwhelmingly - if electric storage weight can be brought down, it looks feasible. Thatís a big Ďifí.
Ha! Neat trick!

Too bad you'd melt tungsten if you only burned the oxygen.

Those other ten pounds are there for cooling and doing work, and even that isn't nearly enough as evidenced by our ROP/LOP hobby.

Batteries also need some of those pounds to cool away the 15% of capacity that escapes as heat during discharge, so the drag advantage isn't as great either.

Open cycle lithium-air batteries could turn the tables in theory, of course. Don't hold your breath though: making those work requires unknown science. You wouldn't want to swap out your fuel tank after a dozen refills.
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  #20  
Old 01-22-2018, 08:28 PM
rv7charlie rv7charlie is offline
 
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Quote:
Originally Posted by Rallylancer122 View Post
When I looked into it the battery density just wasn't there yet for a traditional plane. That's why the few electric airplanes you do see are basically motor gliders. That being said, with some bespoke engineering it's getting close. Check out the Bye Sunflyer.

Some companies aren't waiting around for batteries and are going hybrid electric. Combustion engine drives a generator which in turn drives the electric motor. This sounds inefficient until you look at vertical lift. Getting rid of gearboxes, transmissions, and complicated mechanical flight controls makes it a lot more compelling. Super light motors are everywhere. Now, if I could just figure out where to get a super light generator....?

DEM
Can't speak to efficiency, but those brushless motors will function as generators. Latest automotive tech is using them as starter/generators.
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