200hp Electric Sikorsky
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Hybrid system--??
What about a hybrid system to get around battery limitations, perhaps?
Fit a battery that's just large/heavy enough to provide perhaps 10 minutes of power for takeoff and initial climb, along with a small turbine, say APU size.
Then established in cruise at constant power demand, start the turbine, which would solely power a generator to recharge the battery. Seems to me constant power demand at peak output would reduce the inefficiencies associated with the turbine engine operation and this hybrid plant would be very efficient and reliable.
Thoughts?
Fit a battery that's just large/heavy enough to provide perhaps 10 minutes of power for takeoff and initial climb, along with a small turbine, say APU size.
Then established in cruise at constant power demand, start the turbine, which would solely power a generator to recharge the battery. Seems to me constant power demand at peak output would reduce the inefficiencies associated with the turbine engine operation and this hybrid plant would be very efficient and reliable.
Thoughts?
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Lonewolf 50,
Yes, the coaxial arraignment of; motor, reducer and rotor allows for the use of a planetary gearbox and this has the best power-to-weight of any reducer.
In addition, the motor can have electrical reduction and this can eliminate the mechanical gear box altogether.
onetrack,
Since the discovery and use of high power magnets there are now Permanent Magnet Motors that have very high power-to-weight ratios. In addition, the motor can be significantly overpowered for a short period of time, as long as the heat does not get too high and start demagnetizing the magnets.
Power storage is definitely the problem at present, but a lot of R&D money is looking into it.
arismount,
The hybrid sound like a good near-term solution and perhaps long-term solution for rotorcraft. Eurocopter has a video on the net, which might have been linked to on a previous PPRuNe thread. It shows a full size mockup of a hybrid helicopter. When asked about the timeline, the person being interview smiled and say that maybe in 10 years......
The above sounds like a sales pitch for electric helicopters, but we all seem to agree that electric drives and controls may eventually provide meaningful improvements.
Dave
.... it seems that more than trivial savings will come due to needing fewer reduction gears, and thus a smaller and lighter transmission.
In addition, the motor can have electrical reduction and this can eliminate the mechanical gear box altogether.
onetrack,
Since the discovery and use of high power magnets there are now Permanent Magnet Motors that have very high power-to-weight ratios. In addition, the motor can be significantly overpowered for a short period of time, as long as the heat does not get too high and start demagnetizing the magnets.
Power storage is definitely the problem at present, but a lot of R&D money is looking into it.
arismount,
The hybrid sound like a good near-term solution and perhaps long-term solution for rotorcraft. Eurocopter has a video on the net, which might have been linked to on a previous PPRuNe thread. It shows a full size mockup of a hybrid helicopter. When asked about the timeline, the person being interview smiled and say that maybe in 10 years......
The above sounds like a sales pitch for electric helicopters, but we all seem to agree that electric drives and controls may eventually provide meaningful improvements.
Dave
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Hi Dave,
I am working on a one seat trailerable floatplane now.
I might get back to VTOL designs when the battery technology allows for a high discharge rate with about one or two minutes of extreme power. That's all I would need to launch a fixed wing airplane using multiple electric lift fans.
The batteries should be available in few years. This system of using electric only for launch and landing is sort of what arismount suggested.
I am working on a one seat trailerable floatplane now.
I might get back to VTOL designs when the battery technology allows for a high discharge rate with about one or two minutes of extreme power. That's all I would need to launch a fixed wing airplane using multiple electric lift fans.
The batteries should be available in few years. This system of using electric only for launch and landing is sort of what arismount suggested.
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Electrical systems can be developed around battery in preparation for emergent fuel cell technologies...
Intelligent energy is up to around 500W/kg using proton exchange membrane fuel cells, so only just behind Gaia batteries at 1.5kW/kg. Although Gaia batteries are only at the 0.47 MJ/kg mark, combinations of Li (just below H on periodic table) with other oxidisers may push towards H2/O2 of 16MJ/kg.
Fuel cell plane in aviation first - Intelligent Energy
Aerospace systems - Intelligent Energy
For comparison a tank of Kerosine is around the 45MJ/kg mark because the oxidiser does not need to be carried. Fuel cells can also be air breathing.
Intelligent energy is up to around 500W/kg using proton exchange membrane fuel cells, so only just behind Gaia batteries at 1.5kW/kg. Although Gaia batteries are only at the 0.47 MJ/kg mark, combinations of Li (just below H on periodic table) with other oxidisers may push towards H2/O2 of 16MJ/kg.
Fuel cell plane in aviation first - Intelligent Energy
Aerospace systems - Intelligent Energy
For comparison a tank of Kerosine is around the 45MJ/kg mark because the oxidiser does not need to be carried. Fuel cells can also be air breathing.
Last edited by Graviman; 28th Apr 2011 at 11:47. Reason: Spotted an error in units.
Boeing: Boeing Successfully Flies Fuel Cell-Powered Airplane
Though graviman's links would not open for me, I note Boeing's work on fuel cell powered aircraft, in Spain.
Though graviman's links would not open for me, I note Boeing's work on fuel cell powered aircraft, in Spain.
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A couple of MIGHTs
slowrotor & arismount,
The hydrogen fuel cell may be a solution, but it appears that the current discharge rate is not fast enough for the needs of rotorcraft.
As you mention, aircraft can have a higher than normal power requirement during takeoff. One feature of the hydrogen fuel cell that MIGHT be advantageous is that of applying its byproduct (water) to the motor,s coils, for cooling by evaporation. Wick Idea
This MIGHT be the the source of power for very future rotorcraft; Nuclear Power We Might Be Able to Live With
Dave
The hydrogen fuel cell may be a solution, but it appears that the current discharge rate is not fast enough for the needs of rotorcraft.
As you mention, aircraft can have a higher than normal power requirement during takeoff. One feature of the hydrogen fuel cell that MIGHT be advantageous is that of applying its byproduct (water) to the motor,s coils, for cooling by evaporation. Wick Idea
This MIGHT be the the source of power for very future rotorcraft; Nuclear Power We Might Be Able to Live With
Dave
Dave, about power, and power density estimates.
Is the article you liked to on low energy power generation applying the Blacklight process, or something else? I got a bit confused between reading the article and the links within it, which I had to do, given the article's brevity.
Is the article you liked to on low energy power generation applying the Blacklight process, or something else? I got a bit confused between reading the article and the links within it, which I had to do, given the article's brevity.
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Dave,
Not pooh-poohing the Focardi-Rossi demonstration, but there are plenty of chemical reasons why introducing hydrogen to nickel might give off excess heat. The nickel could just catalyse a reaction with atmospheric oxygen.
Not pooh-poohing the Focardi-Rossi demonstration, but there are plenty of chemical reasons why introducing hydrogen to nickel might give off excess heat. The nickel could just catalyse a reaction with atmospheric oxygen.
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We may be starting to move away from the subject of the Electric Sikorsky. If so Senior Pilot may wish comment.
LoneWolf_50,
However, in response to your question, the following is an e-mail from a person who is much more knowledge on the subject of electrical storage then me.
The BlackLight Process
"I remember being introduced to this page about 2 years ago. I could not corroborate their story, so left it but now after seeing the ECat (energy catalyzer) from Rossi, it seems they are using the same "new" process that everyone is struggling to quantify and describe. Rossi is using Nickel and Hydrogen and says other metals may be used. These guys are using Sodium Hydride and Hydrogen. It all looks very similar and maybe "more than one way to skin a cat". Whatever the outcome, it only looks better and better for risk-free, cheap energy for all."
Dave
LoneWolf_50,
However, in response to your question, the following is an e-mail from a person who is much more knowledge on the subject of electrical storage then me.
The BlackLight Process
"I remember being introduced to this page about 2 years ago. I could not corroborate their story, so left it but now after seeing the ECat (energy catalyzer) from Rossi, it seems they are using the same "new" process that everyone is struggling to quantify and describe. Rossi is using Nickel and Hydrogen and says other metals may be used. These guys are using Sodium Hydride and Hydrogen. It all looks very similar and maybe "more than one way to skin a cat". Whatever the outcome, it only looks better and better for risk-free, cheap energy for all."
Dave
Dave:
Given that the density of electrical power, the volume to weight to stored energy ratios, are critical factors in any electric drive helicopter being commercially viable, I'd guess that this tangent is within the topic we are addressing.
I'll leave it at that, as the processes you linked to look to be in the early stages of development/maturity.
Given that the density of electrical power, the volume to weight to stored energy ratios, are critical factors in any electric drive helicopter being commercially viable, I'd guess that this tangent is within the topic we are addressing.
I'll leave it at that, as the processes you linked to look to be in the early stages of development/maturity.
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In the May/June 2012 issue of Vertiflite, from the head of Sikorsky Innovations;
"Our electric helicopter last year just wasn't ready for prime time. We could have done a flight, but it would have been a stunt. It arguably wouldn't have been safe enough, so we said, 'Let's hold off.'"
Dave
"Our electric helicopter last year just wasn't ready for prime time. We could have done a flight, but it would have been a stunt. It arguably wouldn't have been safe enough, so we said, 'Let's hold off.'"
Dave
Last edited by Dave_Jackson; 21st Jun 2012 at 04:41.
"Our electric helicopter last year just wasn't ready for prime time. We could have done a flight, but it would have been a stunt. It arguably wouldn't have been safe enough, so we said, 'Let's hold off.'"
I looked at it last year at AirVenture. I'll look for it this year and give a report, if warranted.
I looked at it last year at AirVenture. I'll look for it this year and give a report, if warranted.
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slowrotor,
If you want to go 'green' and not wait for batteries to improve, then what about considering a very lightweight Genset?
This is an idea that is being played with.
Dave
If you want to go 'green' and not wait for batteries to improve, then what about considering a very lightweight Genset?
This is an idea that is being played with.
Dave
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onetrack,
I have to agree somewhat with your comments about purely electric propulsion systems for autos or aircraft. While purely (nuclear) electric propulsion makes sense for large ships and subs, it is not yet practical for cars or aircraft, due to limits with battery technology. The motor technology is ready, but the batteries are still way short of where they need to be.
In my opinion, the whole emissions-free, electric drivetrain argument also doesn't make sense. At least here in the US, where 60% of electricity is produced by burning coal and another 20% is produced by nuke plants. Your "electric" helo is, in reality, coal or nuclear powered.
Regards,
riff_raff
I have to agree somewhat with your comments about purely electric propulsion systems for autos or aircraft. While purely (nuclear) electric propulsion makes sense for large ships and subs, it is not yet practical for cars or aircraft, due to limits with battery technology. The motor technology is ready, but the batteries are still way short of where they need to be.
In my opinion, the whole emissions-free, electric drivetrain argument also doesn't make sense. At least here in the US, where 60% of electricity is produced by burning coal and another 20% is produced by nuke plants. Your "electric" helo is, in reality, coal or nuclear powered.
Regards,
riff_raff
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It's comical how no one seems to realize this. People see electricity as clean energy and give no thought what so ever to how it is being produced
Back in the recesses of my mind I can hear Orville making your point to Wilbur... "Maybe we shouldn't.....This thing could wind up crashing and hurting somebody."
Or why da Vinci's invention never left the drawing board.... "Forget it. This thing could wind up screwing up the air."
Electric systems need to be developed. Sikorsky Inovations may have said "Lets hold off" but someone else said "Lets go for it!"
Last edited by fly911; 22nd Jun 2012 at 09:20.
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"If you want to go 'green' and not wait for batteries to improve, then what about considering a very lightweight Genset?"
Dave
No such thing as "Green". (in my opinion)
Even solar cells are made from huge amounts of coal used to refine the silicon.
(up to 25 times more energy than used to make steel, I think some professor calculated)
A genset design might just add more unneeded weight if you try to connect the main engine with various shafts, etc. I think a very small alternator would be enough and avoid some problems.
Dave
No such thing as "Green". (in my opinion)
Even solar cells are made from huge amounts of coal used to refine the silicon.
(up to 25 times more energy than used to make steel, I think some professor calculated)
A genset design might just add more unneeded weight if you try to connect the main engine with various shafts, etc. I think a very small alternator would be enough and avoid some problems.