200hp Electric Sikorsky

[slowrotor]

Aero-news.net reported today that Sikorsky will show a 200hp electric S-300 at EAA Airventure next week.
I will be looking for this.

Aero-News Network (http://www.aero-news.net/index.cfm?ContentBlockID=670286f3-cefd-4f99-8546-fa8f213363a4&)

Sikorsky Introduces 'Project Firefly' Electric Helicopter Demonstrator

Wed, 21 Jul '10

Sikorsky Innovations announced Monday from the Farnborough International Air Show that it has developed an all-electric helicopter technology demonstrator. The Firefly Technology Demonstration Aircraft will be unveiled on July 26 at the EAA AirVenture exhibition in Oshkosh as part of the world symposium on electric aircraft. The demonstrator will be one of the main attractions in the Aviation Learning Center along with other state-of-the-art commercially available and prototype electric aircraft.

"Our objectives with Project Firefly are to provide a proof of principle concept to validate the benefits of an electrically powered rotorcraft; to develop the technologies to enable the manned flight of that technology, and to drive future development of improved, state-of-the-art 'green' technologies and practices," said Chris Van Buiten, Director of Sikorsky Innovations.

In building the demonstrator, the Innovations team replaced the legacy propulsion system of an S-300C helicopter with a high-efficiency electric motor and digital controller from U.S. Hybrid, coupled with a lithium ion energy storage system from Gaia. Integrated sensors provide real-time aircraft health information to the pilot through a panel integrated interactive LCD monitor. Eagle Aviation Technologies, LLC, executed the custom airframe modifications and assembly of the demonstrator aircraft.

"World fuel reserves are continuing to dwindle as demand increases. This inversion of the supply/demand cycle will increase operating costs of all fuel-based vehicles, especially in the aviation industry. Nowhere is this more apparent than in the commercial helicopter market, where the critical role rotorcraft play could be threatened by spiraling fuel costs," said Mark Miller, Vice President, Sikorsky Research & Engineering.

"Many of the most significant advancements in aviation have been enabled by transformations in propulsion technology. It is exciting to be at the forefront of the exploration of electric propulsion technology for rotorcraft," said Miller. "Through the electrical conversion, propulsion efficiency of the aircraft has been increased roughly 300 percent from baseline. Electric propulsion also inherently simplifies the complexity of the propulsion system by reducing the quantity of moving parts, increasing reliability while reducing direct operating costs."

The demonstrator will feature a 200 horsepower electric motor, a motor controller, a battery system, and cockpit controls. First flight is anticipated later this year, upon completion of ground tests and safety of flight reviews in accordance with Sikorsky standard practice for all aircraft programs.

"With current energy storage technology, payload and endurance will fall short of typical helicopter performance. These values will grow as rapidly maturing technology is integrated on the demonstrator," Miller added.

We'll get pictures.

[Graviman]

Interesting...

[onetrack]

This is going to lend a whole new world of meaning to the commonly-announced statement... "I've got a flat battery..." :suspect:

[birrddog]

I'd imagine, engine controls would be more like a turbine than a piston, iow importance of torque and temp (and of course amps).

Wonder if they'll fire it up at Oshkosh so you can hear how quite it is...

[rotorrookie]

awesome, cant wait to the pictures and hear it hover :ok:
wonder if it still has conventional gearbox then just having electric motor replacing the engine, or if it has two motors one for main-rotor and one for tail-rotor which would be cool, then eliminating the need for gearboxes and tail-shaft and lot of moving parts

[Dave_Jackson]

'Sikorsky Innovations'
"In building the demonstrator, the Innovations team replaced the propulsion system with an electric motor and controller from US Hybrid, coupled with a lithium ion energy storage system from Gaia.
Eagle Aviation Technologies executed the custom airframe modifications and assembly of the demonstrator aircraft."

　

Technical innovation. :confused: :confused: :confused:
Perhaps, innovative marketing, so as to claim a http://www.unicopter.com/First.gif.

Dave

[riff_raff]

Dave Jackson,

You nailed it. "Sikorsky Innovations" is probably not the best name for a company division that is the lead on this particular project. All the innovative stuff is COTS from subcontractors. The systems SI is engineering don't appear to be especially challenging.

The motor supplier, US Hybrid (http://ushybrid.com/motor.html), makes PM drive motors that operate well above this aircraft's rotor speed. So I would speculate that some sort of reduction gearbox will still be necessary.

riff_raff

[floatsarmed]

What a complete and total load of of PR Poop!


Electric helicopters eh? For what purpose?

[Pilot DAR]

So the foolish pilot flies too long, and the battery runs down. Enter autorotation, and it recharges the battery on the way down. By the time you get to the bottom to flare, you've got power again! I like the idea!

It will probably be happily difficult to over rev, with the clutch not engaged. I do wonder about type certifying an electric motor as a powerplant though! It looks like we'd need a whole new certification basis for that....

[fly911]

Electric helicopters may seem impractical now, but Igor has probably heard that before. We need a reason to make batteries lighter and motors more powerful. Every journey begins with the first step.

[onetrack]

I have to concur that this media release is a fairly substantial beat-up, and that it has been done to show people that more than lip service is being given to electric drive technology. It could be, that it has been done to place the company in a position to acquire more "green" funding.

There are vast amounts of Govt money available to any company or even an individual who can produce some evidence of a product that shows some advance in the reduction of reliance on hydrocarbon fuels, and a contribution to a greener planet.

However, direct electric drive has a long way to go. The basic problem is that no-one - not even the Li-Ion battery worshippers - can claim that they have an improved battery design, that can come anywhere near the performance of any hydrocarbon-fueled, IC engine.

The basic battery problems stem from inadequate storage and "power-on-demand" capabilities, right through to an inability to recharge quickly.
Caterpillar spun off battery development improvements into a company called Firefly (no relation to Project Firefly).
This new Caterpillar-instigated design involved carbon foam cells that promised vastly improved performance and low cost, as the basic aim of the design being that no metals were required, and carbon is exceptionally low cost, and one of the most common elements.
Unfortunately, the design went nowhere, and Firefly have filed for bankruptcy.

The Swedes have the Effpower battery. A promising lead-acid development that utilises bi-polar plates. Not the bi-polar battery that Microsoft have recently raved about (the one you can insert without reference to correct polarity). No, the Effpower battery design is based around the premise that standard lead-acid batteries only access one side of the plates for power generation. Improving the design so that power is accessed from both sides of the plates makes for a more efficient battery, with lighter weight for power output, and at lower cost than a standard lead-acid battery.

Volvo have poured a heap of money into Effpower, and will shortly be using the Effpower battery in their hybrid vehicles, such as trucks, buses, and some construction equipment.
Hybrid power is the halfway step to all-electric power, and this concept is being embraced by many manufacturers of vehicles and construction equipment.

Their aim is to utilise a smaller engine, (usually a diesel) to drive a reversible generator/motor, that recharges batteries, as well as powering the vehicle/machine, on demand. Regenerative braking turns the electric motor into a battery-charging generator.
Batteries driving the electric motor provide power for lower speeds, and when full power is required, the IC engine adds its power to the electric motor for maximum performance. Volvo will have buses and trucks in production next year, utilising this concept.

There are already excavators in production that utilise hybrid power. They have batteries that power the excavator swing motor, and the swing motor uses regenerative braking for battery charging when it has passed the mid-point of it's swing, and the swing needs to be brought to a stop. The diesel engine also recharges the batteries.
The biggest and most promising development, that really IS a major breakthrough, is the Australian CSIRO-developed Ultrapower battery. This battery utilises standard lead-acid technology, but combines super capacitors in its construction to provide a massive power boost on demand, and to assist with rapid recharge.

The CSIRO claim that lead-acid battery design is a proven principle, and has no major inherent problems, as Ni-MH, and Li-Ion batteries do. In addition, a crucial factor is that lead-acid batteries are 100% recyclable, unlike all other batteries.

This Ultrapower battery is well past the design stage. It has been tested in a hybrid electric vehicle (HEV), and that car has covered over 160,000 kms in testing, with outstanding results. Licences to build the Ultrapower have been given to Furukawa of Japan, and Furukawa has extended the licence to the Advanced Lead-Acid Battery Consortium of America, a group of 54 organisations intent on advancing VRLA battery development.

None of this does anything to seriously advance the possibility of an all-electric chopper. An all-electric chopper will always be hampered by weight considerations of the batteries. A hybrid chopper is a distinct possibility, as hybrid design is currently the most promising technology.

The Ultrapower battery is aimed at HEV's, not 100% electric vehicles; although it is possible that the Ultrapower will be able to meet the demands of an all-electric design. As far as an all-electric, completely-viable chopper? Not in the foreseeable near future, IMO. A hybrid power chopper? Yes, very likely in the foreseeable future.

[riff_raff]

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

[NonSAC]

Dave,

The US Patent Office appears to agree with you, at least insofar as in the way Sikorsky claimed an invention embodying some of these concepts in US Patent Application No. 12/018,217.

US 12/018,217 includes 16 claims; the Office rejected all 16 claims on July 2, 2010 in view of published records of pre-existing work in the field.

Cheers!

United States Patent & Trademark Office (http://portal.uspto.gov/external/portal/pair)

[Ian Corrigible]

I can see a major new business opportunity here for commercial providers of in-flight refueling...

http://i.imgur.com/M0cyMIB.jpg

:E

I/C

[misterbonkers]

Would you have to switch on the power supply at the socket with a second probe? :)

[Pilot DAR]

So, for intercontinental flights, would you need receptical adapters, or would there be different probes available?

[misterbonkers]

Well fat chance on an international standard plug...

[Dave_Jackson]

NonSAC,

As always, thanks again for your support and information.

It is going to be interesting, and educational, to read the Patent Office's rejections against each specific claim. I assume that Sikorsky can still argue against some rejections; IF they feel that they have any valid argument.

_________________________________________________


Here is a more technically realistic approach toward innovation and an electric future.
A 2010: A look at a new innovative EADS helicopter design (http://www.youtube.com/watch?v=YnDkttaDsL8)


Dave

[NonSAC]

Dave,

Fairly cool stuff. The Europeans appear to be focused on solving all the electric motor substitution problems first while allowing the battery industry to solve the power density issue independently - a sensible strategy IMO.

It'll be interesting to see how Sikorsky pursues the rejections in US 12/018,217. They bought their ticket, I'd expect them to finish the ride by responding to the rejections in some manner - though they'll have to pay for someone to write the response.

Whether the argue the rejections, amend the claims, or both depends on how bad the art uncovered by the examiner affects their plans for protecting the technology. Sikorsky's response without extension fees is due 10/2; last day to respond without abandonment is 1/2/2011, so we'll have to wait until then to see.

It's interesting to compare the search report prepared by the Korean Patent Office in the related International Application to that done by the US examiner - the US examiner found a bunch more art. Perhaps Sikorsky will revisit the practice of selecting the KPO as the ISA going forward, and use the USPTO or EPO going forward? Not sure, but my guess is that they were interested in saving some coin.

I'd be curious to see what an EPO examiner would uncover in a search on a related European filing.

Cheers!

[onetrack]

Ian - Shouldn't that picture be more clearly showing an industrial-sized set of booster cables?? :E

NonSAC - Patents are rejected by the hundreds on a daily basis, and it's getter harder to get a patent approved, purely because of the vast number of patents already issued, and the "prior art" reason for rejection. Many companies regularly re-try their applications when they are initially rejected. Then, the companies always face the litigious companies or individuals, who claim, once the item is in production, that the company producing the item, has stolen THEIR idea/s, and infringed THEIR patent/s... :{

[NonSAC]

Interesting points. (Observations are in brackets)

Ian - Shouldn't that picture be more clearly showing an industrial-sized set of booster cables?? http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/evil.gif
(isn't the better question where in the heck does the third 'ground' socket in that plug connect?)

NonSAC - Patents are rejected by the hundreds on a daily basis, (likely true, depends on the country)

and it's getter harder to get a patent approved,
(possibly, depends on the country - in the US yes, but in a place like South Africa not so much)

purely because of the vast number of patents already issued, and the "prior art" reason for rejection.
(way too speculative of an explanation for me to comment on beyond observing that, with many factors including each the law and technology constantly changing, I don't know how to assign causation to any single factor)

Many companies regularly re-try their applications when they are initially rejected.
(I think a better characterization is that they adjust the rights available in view of the examiner's understanding of the state of the art)

Then, the companies always face the litigious companies or individuals, who claim, once the item is in production, that the company producing the item, has stolen THEIR idea/s, and infringed THEIR patent/s... (governments, like the US, set up patent systems with the idea that, in the aggregate, the overall benefit to society outweighs the cost of the right to exclude others from the practice of the invention for a limited period of; maybe so, maybe not...irregardless disputes over ownership of ideas logically follow)

[Dave_Jackson]

NonSAC,

It appears that Third Party Submission played no roll in the USPTO's formal/traditional assessment of patentability. Perhaps it provided support for the examiner's multiple statements of "It would have been obvious to one of ordinary skill in the art at the time of the invention..."

Nevertheless , the assessment is a realistic one IMHO, plus the Submission has become an interesting and educational walk through the patent maze.


:ok: Dave

[Dave_Jackson]

Full-size helicopter runs on 100% electric power | DVICE (http://dvice.com/archives/2010/07/sikorsky.php)

Avionews - Agenzia stampa del settore aeronautico, elicotteristico, aerospaziale e della difesa (http://www.avionews.com/index.php?corpo=see_news_home.php&news_id=1119512&pagina_chiamante=index.php)

[Hank195]

From the EAA's daily update on Oshkosh - (I suspect flight time "with reserves" would not meet the JAA / FAA's definition of VFR or IFR fuel reserves:))


Watt's up at Sikorsky
By Peter Lert

Drop into the Aviation Learning Center and you'll see what at first glance looks like an aerial application version of the Schweizer 300 helicopter, minus the spray booms but retaining the big pesticide tanks. A second glance, however, reveals that these are actually battery enclosures; look between them and you realize that the 200-hp Lycoming is gone, replaced by an electric motor. Gone, also, are the original fuel tanks, as well as the maze of wiring and plumbing that decorated the original reciprocating engine installation.

This is Project Firefly, a research platform under development by Sikorsky Innovations in Stratford, Connecticut. Project engineer Jonathan Hartman explained that they began with a proven existing airframe to minimize re-engineering, then developed the electric power package to replicate the operating characteristics of the original gasoline engine. Thus, the 142 kW (190 hp) permanent magnet motor, developed by US Hybrid in Torrance, California, is mounted in the same location and has the same output shaft speed as the standard IO-360.

Everything "downstream" of the engine output pulley is the same as in the original helicopter, including the multi-V-belt primary drive, sprag clutch, transmission, and rotor system. The motor itself was originally developed for surface vehicle programs including electric trucks for the Port of Los Angeles and an electric-powered Humvee for the U.S. Marine Corps; converting it for the helicopter involved modifying its rpm and torque characteristics and changing from water to air cooling. US Hybrid also developed the motor controller, while the lithium-ion battery cells come from Gaia in Germany.

Total capacity of the 1,100-pound battery is 48.1 kWh, which should allow a flight time of approximately 15 minutes with reserves. First flight is expected later this year; at present, the Firefly helicopter is continuing with ground runs to validate the power system and gather data. Hartman noted that with an expected order of magnitude improvement in battery capability, they could begin thinking about real-world applications.
This fits with the generally established idea that a 20-fold improvement in battery capacity for a given weight would be directly comparable to internal-combustion power systems.

For more information, visit www.Sikorsky.com.

[Lonewolf_50]

This fits with the generally established idea that a 20-fold improvement in battery capacity for a given weight would be directly comparable to internal-combustion power systems.
If I may be so bold, in the past 30 years, what-fold improvement in batter capacity has been realized? Battery tech does not seem to follow Moore's Law. ;)

That's an interesting hand wave there, from the folks on the banks of the Housatonic.

[Dave_Jackson]

The best foreseen improvement, which is only in the R & D stages at present, is for a 10-fold increase over lithium-ion.


IMO, this is no more than a PR stunt to perhaps claim a 1st in electric flight. Should this be Sikorsky's intent, they may wish to read page 3 of this article on the Hummingbird. (http://www.vertical-aviation.com/tools/nl/Hummingbird-NL-Fall-2009.pdf) It has been stated by a separate source that it did leave the ground.

Dave

[Ian Corrigible]

Dave - Interesting link, hadn't heard of the electric Hummingbird effort before.

Sikorsky's assumptions regarding battery improvements makes NASA's own assumptions for the Puffin (http://www.pprune.org/rotorheads/402939-single-seat-v-22-contender.html) tailsitter - namely a three-fold improvement in power density by 2017 - seem tame by comparison!

I/C

[Smoketoomuch]

A 500kg battery? Hmm, that's a lot of weight.
All from memory so don't bite my head off;

Energy density of petrol/diesel/avgas etc is about 40MJ/Kg [MJ= MegaJoules]
Best current battery is about 1MJ/Kg, and they are extremely fragile. I would feel fairly safe hitting a fuel tank with a hammer - do it to a lithium-ion battery and it will catch fire. Most battery advances seem to be based on ever finer manufacturing techniques, literally nano-technology, and presumably more fragile. It would flying around with a tank of nitroglycerine in the back.

Is this Sikorsky unmanned?

Modern electric motors are about twice as efficient as IC engines, but an order of magnitude improvement in battery energy density will still only get you half as far. Fuel-cells might be a better option, but they keep on stubbornly refusing to live up to their potential. Pun intended :)

[AdamFrisch]

I don't know what kind of batteries Sikorsky are using, but I can tell you that something is wrong here, either with the figures or the batteries used.

48.1kWh and 1100 pounds. Let's dissect this; That's 48.100Wh and 500kg. That translates to 96Wh/kg.

I can buy off the shelf Li-Ion batteries that deliver about 400Wh/kg, so what kind of stuff have Sikorsky been using? Lead acid?

400Wh/kg would give the same helicopter an hours endurance. That's a huge difference.

[Dave_Jackson]

AdamFrisch,

It is said that there is a big difference in the reliability of lithium-ion batteries, depending on the supplier. In addition, the weight of connecting and monitoring very large assemblies of much smaller individual batteries adds 10-15% to the weight.

Sikorsky, being a large and well known company, is probably weighing any damage to it's reputation against that of extended flying time.

Dave

[Dave_Jackson]

Silent flight: Sikorsky's electric helicopter ~ from 'the Engineer' (http://www.theengineer.co.uk/silent-flight-sikorskys-electric-helicopter/1006012.article)

[Dave_Jackson]

The following is a 54 page NACA document from 1981.
It evaluates the building of an electric Hughes 269A helicopter.

For the interested, it is easy to read and it may be the foundation of the electric Firefly.

PRACTICAL FEASIBILITY ASSESSMENT OF ELECTRIC POWER PROPULSION IN SMALL HELICOPTERS USING LITHIUM HYROXIDE BATTERY TECHNOLOGY (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19830072375_1983072375.pdf)


Dave

[slowrotor]

Interesting study Dave.
So what has happened with lithium hydroxide in the last 30 years?
I think maybe the recycling of the waste is the problem.

[Thomas coupling]

February With the world going mobile and billions of new devices requiring electrical storage, battery technology is almost certainly due for a renaissance in the near future and recent developments suggest MIT will play a role in the next significant battery technology. Less than a week ago, we reported on work being done by MIT's Laboratory for Electromagnetic and Electronic Systems (LEES) that could become the first technologically significant and economically viable alternative to conventional batteries in 200 years. Now a second new and highly promising battery technology is emerging from MIT - a new type of lithium battery that could become a cheaper alternative to the batteries that now power hybrid electric cars.

Until now, lithium batteries have not had the rapid charging capability or safety level needed for use in cars. Hybrid cars now run on nickel metal hydride batteries, which power an electric motor and can rapidly recharge while the car is decelerating or standing still.

But lithium nickel manganese oxide, described in a paper to be published in Science on Feb. 17, could revolutionize the hybrid car industry -- a sector that has "enormous growth potential," says Gerbrand Ceder, MIT professor of materials science and engineering, who led the project.

"The writing is on the wall. It's clearly happening," said Ceder, who said that a couple of companies are already interested in licensing the new lithium battery technology.

The new material is more stable (and thus safer) than lithium cobalt oxide batteries, which are used to power small electronic devices like cell phones, laptop computers, rechargeable personal digital assistants (PDAs) and such medical devices as pacemakers.

The small safety risk posed by lithium cobalt oxide is manageable in small devices but makes the material not viable for the larger batteries needed to run hybrid cars, Ceder said. Cobalt is also fairly expensive, he said.

The MIT team's new lithium battery contains manganese and nickel, which are cheaper than cobalt.

Scientists already knew that lithium nickel manganese oxide could store a lot of energy, but the material took too long to charge to be commercially useful. The MIT researchers set out to modify the material's structure to make it capable of charging and discharging more quickly.

Lithium nickel manganese oxide consists of layers of metal (nickel and manganese) separated from lithium layers by oxygen. The major problem with the compound was that the crystalline structure was too "disordered," meaning that the nickel and lithium were drawn to each other, interfering with the flow of lithium ions and slowing down the charging rate.

Lithium ions carry the battery's charge, so to maximize the speed at which the battery can charge and discharge, the researchers designed and synthesized a material with a very ordered crystalline structure, allowing lithium ions to freely flow between the metal layers.

A battery made from the new material can charge or discharge in about 10 minutes -- about 10 times faster than the unmodified lithium nickel manganese oxide. That brings it much closer to the timeframe needed for hybrid car batteries, Ceder said.

Before the material can be used commercially, the manufacturing process needs to be made less expensive, and a few other modifications will likely be necessary, Ceder said.

Other potential applications for the new lithium battery include power tools, electric bikes, and power backup for renewable energy sources.

The lead author on the research paper is Kisuk Kang, a graduate student in Ceder's lab. Ying Shirley Meng, a postdoctoral associate in materials science and engineering at MIT, and Julien Breger and Clare P. Grey of the State University of New York at Stony Brook are also authors on the paper.

The research was funded by the National Science Foundation and the U.S. Department of Energy.

Still, it adds a whole new meaning to: WHISPER MODE:hmm:

[AdamFrisch]

Like I've harped on about in countless threads - electric is the future of all transport, especially aviation. But it perhaps makes even more sense for helicopters - rapid startups, no tail rotor coupling, more silent, less cost, high altitude etc etc. List is endless.

I read that the new Sikorsky S-76D has a tag price of $13 million. That's a lot of money for something that's basically designed in 1976. Electric propulsion will be able to bypass all the corporate greed from engine manufacturers charging an arm an a leg for something that isn't that complicated, just because the customer can't go anywhere else. Electric will level the field.

I hope these new Lithium Nickel cells become as good as they sound.

[Lonewolf_50]

Adam, from a design perspective, is an electric motor of a given HP rating smaller than a hydrocarbon motor of similar HP rating? :confused: (The ratio of power and/or capacity to weight is another major design factor, is it not?)

If I get electric drive, but add more weight to get it, what have I gained?

I find this line of progress analogous to the environmental constraints on using various chemicals for industrial processes. The processes become, in some cases, more expensive or more time consuming. The benefit from that cost being "less poison" and therefore less cost to clean up. Chemists keep on working to mitigate those constraints.

The breakthrough in fuel and power technology to replace hydrocarbons for this particular application (aviatoin) has yet to be found. Don't mean to rain on the parade, but I don't think electricity is the golden bullet in this battle.

[AdamFrisch]

Oh, much, much smaller. In fact, much smaller than turbines. You can get about 10Kw (that's 13.7hp) from 1kg of brushless motor. That's 10:1. Not a single gas turbine can even come close to those power-to-weight ratios. They do roughly 5:1 at best. And combustion engines do about 1:10, so they're really inefficient.

But as you hinted at, that's only half the story. When you add energy storage to this you presently add on a lot of weight. It's the energy storage that needs to be solved - the propulsion/prime mover is fine and already there. That's why the breakthrough will come through batteries or power cells and why that's so important to solve. Great progress has been made in this department (just think of how small and how long your phone keeps its charge compared to your first portable cell) but much more is needed before it can be a viable alternative. We'll get there though, and faster than people think.

[Dave_Jackson]

Hi slowrotor. You've been quiet for a while. Any new project?

So what has happened with lithium hydroxide in the last 30 years?
http://www.unicopter.com/NoIdea.gif
There sure appears to be a lot of research going on now. However, like the implementation of the reciprocating engine, the helicopter may be one of the last modes of transportation to go electric.


This 30-year-old NASA report by Hughes Helicopters and Continental has the electric motor and the rotor on a common axis. This logical arrangement is what Sikorsky is currently attempting to patent.

Dave

[Lonewolf_50]

Dave, from what you descrive, it seems that more than trivial savings will come due to needing fewer reduction gears, and thus a smaller and lighter transmission.

[onetrack]

It's not only energy storage that has a weight problem. The last time I lifted a sizeable electric motor, it didn't exactly float free from its mountings .. :rolleyes:
Electric motors are heavy, period... and no-one has come up with a super-lightweight electric motor yet... along with the super-lightweight battery, to go with it.

The all-electric drive system also suffers from more rapid rundown as the energy source is depleted... as many electric car users are finding, by becoming stranded, when the battery power gives out far more rapidly than they expected.

I've no doubt that electric power holds promise. The major problem is that a real breakthrough is required to advance all-electric drive systems to the point where they can become a real competitor to hydrocarbon power.
Electric cars will soon have their place in inner-city, short-trip movements... but for long distance travel by road, and for travel by air, we are still looking at hydrocarbons in the foreseeable future.

The hydrocarbons source may alter from oil to gas (coal seam or natural gas), but hydrocarbon power isn't going to be easily or rapidly displaced, certainly not within the next 20 years... peak oil or no peak oil.

[arismount]

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?

[Dave_Jackson]

Lonewolf 50, .... it seems that more than trivial savings will come due to needing fewer reduction gears, and thus a smaller and lighter transmission. 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

[slowrotor]

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.

[Graviman]

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 (http://www.intelligent-energy.com/news_events_and_press/news/archive/38/)

Aerospace systems - Intelligent Energy (http://www.intelligent-energy.com/products_and_services/fuel_cells/power_systems/aerospace_systems/)

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.

[Lonewolf_50]

Boeing: Boeing Successfully Flies Fuel Cell-Powered Airplane (http://www.boeing.com/news/releases/2008/q2/080403a_nr.html)

Though graviman's links would not open for me, I note Boeing's work on fuel cell powered aircraft, in Spain.

[Dave_Jackson]

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 (http://www.unicopter.com/1956.html#Water_Cooling)


This MIGHT be the the source of power for very future rotorcraft; Nuclear Power We Might Be Able to Live With (http://evworld.com/article.cfm?storyid=1977)


Dave

[Lonewolf_50]

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.

[Graviman]

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.

[Dave_Jackson]

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 (http://www.blacklightpower.com/process.shtml)

"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]

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.

[Dave_Jackson]

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

[rotorfan]

"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.

[slowrotor]

So the whole thing is just "Green" marketing?

At least they gave me a free T-Shirt last year at the Airventure tent.

[Dave_Jackson]

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. (http://www.unicopter.com/2141.html)


Dave

[cbox chip]

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

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, Coal power generates 44% of the US's electricity and 39% of its CO2 emissions. natural gas is no where near as dirty but it still creates CO2. Ironically residents who live near coal power plants are exposed to higher radiation levels than those living near nuclear plants as well.

[fly911]

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
CBOX, try not to let yourself get to the point of throwing the baby out with the bath water. Electricity IS clean energy. What it is generated from is a whole nother issue. Whether you charge a battery with coal or solar cells doesn't change how clean or dirty an electric motor or a battery is.
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!"

[slowrotor]

"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.