Electric Airplanes!

R P said:
Go down to a floatplane base, and watch a few planes take off. You will hear a very loud high pitched rapping sound as they reach full throttle which will last until they climb out and throttle back for cruise. That noise is created as the propeller tips reach near the speed of sound.

www.faegre.org › files › AF-seaplane-noise-2002
PDF
Dec 15, 1995 - The majority of the noise coming from a propeller aircraft is created at the tips of the propeller; there is not much coming from the exhaust pipe. ... Finally, a 10% increase in distance between the seaplane and the noise sensitive source results in a decrease in the sound level received by 1.0 dBA
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Thanks for the articles RP. With electric flight, it is just too easy to have dual or triple rotors, running at a lower speed. Hopefully that will generate less tip screaming.
 
Kwathouer said:
Thanks for the articles RP. With electric flight, it is just too easy to have dual or triple rotors, running at a lower speed. Hopefully that will generate less tip screaming.
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Yes, that is very true actually. But even single electric motors can have longer propellers (more efficient) that turn at lower rpm. The problem with a smaller piston driven airplane is that they need 2700 rpm (low by car standards) to generate full power, and are equipped to provide the longest prop possible (most efficient) that does not have a tip speed too close to the speed of sound.

Larger turbine propped planes (small commuter types) have reduction drives, and with their greater ground clearance can turn longer and slower turning props that are not as noisy. Floatplanes are often the worst, because it takes so much power to get off the water. Once in the air, all planes can use lower power to cruise, and are less noisy.
 
R P said:
More info on first flight, batteries, and when pax service expected.
https://copanational.org/en/2019/12...dium=email&utm_campaign=COPA+eFlight-20191212
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Further to the Harbour Air test flight from last Dec, this latest article reveals that only 15 minutes of flight with 25 minutes reserve is available. Seems they need to increase that a bit more before flights between the Island and Mainland become feasible.
https://copanational.org/en/2020/08...dium=email&utm_campaign=COPA+eFlight-20200820
Still looks like a good application for this new technology with these short haul flights (30 minutes). Hopefully they will soon find a battery that will meet these requirements.
 
R P said:
Still looks like a good application for this new technology with these short haul flights (30 minutes). Hopefully they will soon find a battery that will meet these requirements.
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I am pretty skeptical of Dahn's work - as to their impact on the commercial products. Lithium-ion has improved only 3% in the past decade, and after reading some of his papers, I believe his practical improvements is less than 10% in energy density. Thus they will never see the light of day, as there is a huge chasm between lab work and a commercial product. The improvement in batteries will most probably come from solid state batteries and lithium-sulfur batteries. Neither of which he is working on, AFAIK. Interesting RP, you are in Vancouver? So am I.

Harbour Air, as commendable as they are, know that to have commercial flights, they need to increase the battery capacity to at least 100 kWh. That is about 400 kg of mass, which will then greatly lower the carrying capacity of the Beaver. They are much better off with a serial hybrid, or an aerodynamic amphibian. And then there is no regulatory authorization for lithium-ion flight in the commercial sector in the US or Canada, or even in the private non-experimental sector. So it will be a long time before we see Harbour Air offering scheduled electric flights. Unless solid state or LiS batteries become cheaply available.
 
Yeah, the progress is never as great as the promise. I have had electric bikes for 5 years now, and looking back at the battery packs I bought back then, they still cost the same, and do not have any more power for the weight.
 
R P said:
Yeah, the progress is never as great as the promise. I have had electric bikes for 5 years now, and looking back at the battery packs I bought back then, they still cost the same, and do not have any more power for the weight.
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Is there a way I can DM you on this board?

I think for lighter aerodynamic airplanes, it is possible to have them electrified. The Pipistrel Alpha electric, the only one in Canada which resides in the Pitt Meadows airport will fly 2 hours, and is a great trainer. There is video of it flying on UT. I am also thinking of doing the same, but starting from a kit airplane, and building the power drive myself.
 
Kwathouer said:
Is there a way I can DM you on this board?

I think for lighter aerodynamic airplanes, it is possible to have them electrified. The Pipistrel Alpha electric, the only one in Canada which resides in the Pitt Meadows airport will fly 2 hours, and is a great trainer. There is video of it flying on UT. I am also thinking of doing the same, but starting from a kit airplane, and building the power drive myself.
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Yeah, that plane works as trainer, as most flight lessons are only 1 hour. But after that they still need to recharge it, which likely will take a few hours at least. So again, not the most productive flight school airplane. I am actually a pilot, if you haven't guessed so far.

And yes, feel free to DM me. Just go to your inbox and "start a new conversation".
 
R P said:
Hydrogen powered airliner in 15 years?
https://www.avweb.com/aviation-news/airbus-launches-hydrogen-based-zeroe-initiative/?MailingID=458
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I hope they do well with their research and development, but I and probably many others would feel a little less than secure knowing that any kind of problem cooling and maintaining that liquid hydrogen at -423 degrees F would result in disaster.
https://www.sciencedaily.com/releas...d their launch,self-ignition of such mixtures.
 
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electriceddy said:
I hope they do well with their research and development, but I and probably many others would feel a little less than secure knowing that any kind of problem cooling and maintaining that liquid hydrogen at -423 degrees F would result in disaster.
https://www.sciencedaily.com/releases/2016/06/160616105904.htm#:~:text=Hydrogen droplet size affects the mechanism of burning,-Date: June 16&text=Modern rockets and their launch,self-ignition of such mixtures.
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Yeah, no easy answers, same can be said by for LiIon based batteries (fire danger) in the air. But glad to see they are working on it, and will see what works out in the end.
 
electriceddy said:
I hope they do well with their research and development, but I and probably many others would feel a little less than secure knowing that any kind of problem cooling and maintaining that liquid hydrogen at -423 degrees F would result in disaster.
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Hydrogen will never become a viable fuel for aviation, even for EVs. Hydrogen fuel cells currently run only at 50% efficiency.

For EVs, formic acid is a far better way to store and carry hydrogen fuel.
 
R P said:
These are the same guys that were behind the Harbour Air Beaver test back last Dec. Seems like hydrogen and electric can make it happen sooner for the airline sized planes.
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Hydrogen will never become a viable fuel for aviation IMO, even for EVs. Hydrogen fuel cells currently run only at 50% efficiency, and add a lot of weight and require cooling.

For EVs, formic acid is a far better way to store and carry hydrogen fuel. But that is too heavy for aviation.
 
So why are all these large corps working on it? Are they just trying to throw away their R&D money?
 
R P said:
So why are all these large corps working on it? Are they just trying to throw away their R&D money?
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Hi R P - hope all is well, given that woman Henry the Rabbit who is trying to infect us all.

These large corps need to buy good PR for themselves on a continuous basis. Hydrogen has a cachet that the modern media, unable to understand and report anything factually, keeps on promoting as the next best thing since sliced bread, in order to garner eyeballs. Hydrogen has a good name because it is clean. That is all what the enviros care because cost for them does not matter. Cost for the enviros means you either tax people or you print money. So the big corps need to show their 'virtues' by promoting hydrogen, and receive greenwash brownie points, so the activists would leave them alone. Why would an activist attack a big monopoly corp that is working on hydrogen and pushes diversity training and is saving the oceans from plastics? Big corps are now on the good side of the ledgers of activists and bureaucrats. What they spend on hydrogen is short change for them, and they probably get some very complicated tax credits for that too.

Who is going to pay for the trillions of dollars of hydrogen infrastructure? Not the big corps. It will be me and you.
 
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