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  #71  
Old 12-16-2020, 08:52 AM
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Snowflake Snowflake is offline
 
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Location: Sidney, BC, Canada
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Quote:
Originally Posted by sailvi767 View Post
The test Beaver used a Lithium ion battery pack.
I had to go back and find the pilot's statement to confirm, but you're right! Here's what he said:

Quote:
Originally Posted by HarbourAir
“What certainly hasn’t been done before is to fill a Beaver’s cabin with lithium-ion batteries, taking the plane to its gross weight. As a technology demonstrator, this eBeaver isn’t carrying passengers — there isn’t room — and will only have a 15-minute endurance with a 25-minute reserve.

These are batteries that NASA is using, but they’re not batteries that we’d use if we were going to try and make it economical to fly today, because they’re very low in watt-hours per kilogram...”
The takeaway is that they used batteries that were nowhere near the current technology standard. Moving to a Tesla-style pack that optimizes use of space better would cut the size in half. And moving to newer battery tech would cut it in half again.
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  #72  
Old 12-16-2020, 09:33 AM
AlpineYoda AlpineYoda is offline
 
Join Date: Nov 2019
Location: Boulder, CO
Posts: 418
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Quote:
Originally Posted by Cumulo View Post
https://www.cnet.com/roadshow/review...i-nexo-review/

The Hyundia Nexo. Hydrogen fuel cell/ lithium battery. 161 HP, 291 ft lbs torque. Cool.

Buy one(~$60K), strip the motor, fuel cell and battery, add bulbous tip tanks for the bulky hydrogen fuel and fly 1500 miles. We're THERE! Electric flight.
An aircraft full of hydrogen. Nothing has ever gone wrong with that.
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  #73  
Old 12-17-2020, 09:54 AM
YvesCH YvesCH is offline
 
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Location: Basel, Switzerland
Posts: 260
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There is a company in Switzerland building a hybrig aircraft with a Rotax for cruise and charging and a battery for near airport operations.
http://www.smartflyer.ch/aircraft/
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  #74  
Old 12-17-2020, 10:17 AM
David Paule David Paule is offline
 
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Location: Boulder, CO
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I once worked on the design of a hydrogen fuel tank for a hydrogen-powered airplane. The entire fuselage shape was designed to accommodate the tank, which was relatively large for the mass of fuel it contained, hydrogen being low-density. The volumetric energy density of hydrogen is low.

The tank itself was significantly more complex and difficult than a liquid fuel tank would have been, even though (I think) it might have been fueled with liquid hydrogen. As the hydrogen got used, it changed to a gas. Fuel tanks and airplanes being what they are, the tank needed to be able to withstand but internal pressure and a vacuum, as well as the normal flight loads.

Bottom line is that it'll be a while before hydrogen fuel can be used on our kit airplanes.

Dave
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  #75  
Old 12-17-2020, 02:51 PM
AlpineYoda AlpineYoda is offline
 
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Location: Boulder, CO
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Quote:
Originally Posted by David Paule View Post
Fuel tanks and airplanes being what they are, the tank needed to be able to withstand but internal pressure and a vacuum, as well as the normal flight loads.

Bottom line is that it'll be a while before hydrogen fuel can be used on our kit airplanes.

Dave
I think Dave wins the prize for understatement of the year. Given how much trouble people have building Van's tanks that are able to withstand 1 PSI, and how many QB tanks even come from the factory with leaks, whatever pressures Dave was using in his experimental planes are well out of reach of our meager rivet-and-proseal skills.
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  #76  
Old 12-17-2020, 03:37 PM
David Paule David Paule is offline
 
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While the airplane would be considered experimental if we built it, it was developed for a governmental entity. I was fairly far down that line, being a consultant to a contractor to the company that was developing the airframe.

One thing I remembered was that my client had difficulty with both the physical construction of the tank and the verification of it. They needed to create some dedicated test equipment, even beyond the tank. I don't know how that project finished because I retired right after my phase was done. But later I did see a photo of the airplane in Aviation Week, flying. I have no knowledge of whether the tank I worked on was used. Other changes were evident.

Really, this just ain't gonna happen in our world. Stick with liquid fuels and think about electricity.

Dave
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  #77  
Old 12-17-2020, 04:53 PM
PilotjohnS PilotjohnS is online now
 
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Location: Southwest, USA
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Default low tech

I think a really long extension cord is lighter than current batteries for the same amount of endurance.
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WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

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  #78  
Old 12-17-2020, 05:26 PM
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Ironflight Ironflight is offline
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Location: Dayton, NV
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Quote:
Originally Posted by PilotjohnS View Post
I think a really long extension cord is lighter than current batteries for the same amount of endurance.
Well I guess that would return many of us to our aviation roots....U-Control!!
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  #79  
Old 12-18-2020, 07:40 AM
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BillL BillL is offline
 
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Quote:
Originally Posted by Ironflight View Post
Well I guess that would return many of us to our aviation roots....U-Control!!
But don't cross the streams!!!
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  #80  
Old 12-18-2020, 02:13 PM
zolotiyeruki zolotiyeruki is offline
 
Join Date: Feb 2020
Location: Oswego, IL
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One thing I haven't seen discussed much WRT to electric-powered aircraft is cooling drag. If you're cruising at 150HP and 33% efficiency on an ICE, you have to dissipate 300HP worth of heat. Cruise at 150HP with an electric motor, and you're dissipating somewhere in the region of 15HP of heat. If cooling drag accounts for about 7% of all drag, it's not a huge percentage, but it does move the needle a bit.

On the subject of hybrid engines, I'd love to see Toyota build one. The Prius hybrid systems have a very good reputation for reliability.

But what I'd *really* like to see is a diesel-electric fuel cell system. You'd get the range and speedy refueling of a traditional aircraft, the efficiency and lower cooling drag of electric motors, and the low cost of Jet-A.
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