Electric R22 anyone?
 

Just thinking out of the box...

If you take a Robinson R22 and remove the Lycoming engine, battery, alternator, drive shafts, clutch, belts, and both gearboxes, fuel tanks, how much does the unpowered fuselage weigh?

Now, if you replace all of those components with a pair of DC electric motors - a big one driving the main rotor and a little one in the tail - control equipment and as many Lithium-Ion batteries as you could carry up to the same weight, how much endurance would the resulting eco-friendly machine have?

I'm not an engineer, and I don't have ready access to the numbers, but I know that:

- Electric motors are a lot lighter than piston engines
- Electric motors are way more efficient
- Startup, shutdown and carb icing wouldn't be problems any more
- There would be a lot less moving parts, and reliability would be increased
- The end result would be eco-friendly and very cheap to run!

However...

- Avgas has *much* higher energy density than, say, lithium-ion batteries
(this is probably the showstopper - figures, anyone?)
- Power and control systems would be critical to safe flight

If we get the weight & balance right, who's up for a ride in the result??

Benet

Excellent idea, now if you also change the dynamic weights on just one of the blades to cause a slight imbalance...you have your very own cafe latte whisker:D :D :D

Benet,

I suggest that you have a look at the current electric radio controlled helicopters beginning to enter the market. They do not rely on Li-Cells but on a new type of cell that have a greatly improved power-density (the name escapes me). These machines have an endurance of about 7 minutes. WOW!

The all-electric-rotorcraft is not a new idea, the combination of modern gas turbines with shaft mounted integral high-speed electrical generators powering electrical motors via power-electronics has been bounced around by most of the big companies for years. Interestingly, the major motivation of this move would be an increase in system reliability rather than a performance/weight benefit. We are currently waiting for the technology to catch up with the concept, then i'm sure this stuff will start to make an appearance in the aircraft.

Hope this helps,
CRAN
:cool:

Mr. Volta, what hath thou wrought
 

There is a man here in Canada that is working in conjunction with Siemans or one of their subsidiaries to use a motor that is powered by magnetic energy that is self contained and does not need an external electrical force. From what he told me this type of motor has already been developed now all they have to do is scale it up to power an aircraft or a helicopter.

:E :E

A contribution to the thread
 

Now come on Lu... this sounds like the magic water-powered car one reads about on some forums. In order to do any useful work a motor has to get energy from somewhere.

Moreover I hoped you might be able to chip in with a bit of the engineering knowledge, such as the weights of components I mentioned. Any chance? Then we can know how much weight we've got to play with!

Cran: I'm not aiming to develop a hybrid, where electric motors are used purely for transmission. We have hybrid cars nowadays - to my mind they are horribly over-engineered.

I'm hoping someone with knowledge of battery systems can throw in some numbers as well. I've read that Li-ion batteries store about 120 watt/hours per kg, for starters...

Benet

bennet
 

i would think that the weight of the batteries involved is the problem and the time spent "hot recharging" could be an issue aswell.
your 120w / kg battery would have the same performance as the engine in my car if it weighed 1000kg's
also im pretty sure 120watts per hour is 2 watts per minute if you want it to last for the hour. (120w for 1 minute)
i dont know if i am correct but im sure somone does :confused:

Li-poly and Li-ion batteries are great but they are very finicky. If you charge them wrong, too hot, too quickly, they have a tendency to catch fire very quickly. Also they would get extremely hot pumping out the juice required for your two electric motors.

Batteries = TOO MUCH WEIGHT & DANGER

If, in the distant future, this were to be useful - you would need to do it via fuel cell technology. The problem, within the limits of TODAY'S capabilities, is that you simply can't carry enough H2. I've read some interesting research on microfibers that allow you to trap more H2 molecules, hence increasing the amount of H2 you can carry in one cylinder. Still, I think it will be 20-30 years before something efficient is put together.

A fly in the ointment. Or is tha an oint in the flyment?
 

If you have ever cranked up a Bell helicopter with the battery in the nose you will have noted the spinning of the magnetic compass. Is it possible that you will have the same effect but on a continuous basis if you power the driveline with DC motors.

:E :confused: :E

Imagine the helo landing next to the bowser and asking for 37 Coulombs of electrons, please.

The problem with electric motors is how to store the electrons. We all know that only round electrons can roll through wires, but they are not easily stacked up.

Flat electrons are stacked into batteries, but need a convertor to change their shape into round electrons to get into the wires. So, will this helicopter run on round or flat?

And what if, by accident, some of the coloured electrons (which normally run around in neon signs) get into the engine? Will it leave coloured trails in the sky? Might be handy for airshows, though...:8

A.C., they would surely have to be round ones, otherwise you would get an interrupt in the rotation of the blades as the corners of the flat ones got caught in the power cable.

It may be possible to use tape wire (like you see down the side of a building as a lightning conductor) to avoid the need for a converter to change them.

I believe that it is possible to de-colour them. There is a chap here who makes good money taking the colour out of the diesel he buys in China, so the same principle could be applied.

You see, all it needs is Good Science, and Rotorheads can solve all these technical problems. :D

You guys are barking up the wrong tree.
Obviously the batteries are the sticking point; too heavy, too dangerous, so get rid of 'em - use a mains outlet and a very, very long extension cord.

AC,

You've obviously been in contact with the fellow in Vancouver, who has made some startling breakthroughs in his development of oval electrons? Could be the interface that you are looking for.

Not sure how they affect the colouration aspect, though. Could be they will be up into the ultra violet spectrum, and only cause distress to pets, rather than the public.

in the motoring supplement of yesterday's sunday times there is an article regarding an attempt at the electric-land speed record. using a new type of battery [radial cell??] they hope to break the 300mph limit, but the batteries are only good for 7 minutes or so.

Everything that's old is new again...
 

Just to let you know, that this has been done.

Back in the 80's Orlando Helicopters (the group that created the WhisperJet and Hummingbird kit) successfully flew a Sikorsky S-52 (HO5S-1) on battery power. I believe they were using lead-acid batteries and a torpedo motor. I'm sure it was a pretty short flight, but proved (?) the concept.



BTW, Do you really think they're keeping it up for seven minutes, or does it just seem like seven minutes? ;)

HOSS-1

nasa have actualy just developed new wire cable to convert the flat electrons into round ones, by narrowing the cable down (like a funnel) it squashes them into a ball which greatly increases the rate at which work can be done. the angle of narrowing (commonly called phase angle) and the use of fully ridgid insulation that goes hard after its heated, seems to be the winning factor.

:E

Vorticey, I guess nasa is the Northern Australian Science Academy.

I understand that their research into the conductivity of large piles of empty tinnies, when wired to the mains to stop urinators has received high acclaim, as far afield as Tennant Creek. :D

More
 

everyone that has done formal training knows that the electron's name is phil and they even made a film about him. what he does is throw his body forward down the line and his feet follow. this is different to the french belief in holes and it moves in the opp direction.Colouris just the shirt that phil is wearing at the time.

Why would you want to use batteries ?
 

My craizy theory is that for more than 30 years Oil companies have (partially) sponsored battery research projects in the car industry to make shure we would still use lots of fosil fuels, because batteries simply are not the answer.
One of the interesting research outcomes is for instance that using a small solar panel, driving a little fan can efficiently cool the car in the summer on the parking : bid deal ...

A small calculation shows how inefficient batteries are :

A diesel can get 30-38% effficiency.
A fosile power plant max 38%, Nuclear because of safety 33%, say average 35%
Transmission efficiency is 95%, battery loading 95%, electrical motor efficiency 90%.
Together : 35%*95%*95%*90%= 28%
Storage, distribution of fuel is far easier, the current power system simply cannot transport these amounts, certainly not if peak power is wanted (for charging).

The remaining 60% in cars and helicopters is also used for heating, so the total 'co-generation' efficiency is higher than 30-38%, I would say by at least 5%, certainly in helicopters where you tend to encounter colder air.

Ecologically speaking : what to do with all the cupper and most important the batteries that are far from ecological.

I would stick to a diesel.

Thanks for your thoughts everyone, but there are some real misconceptions here which need looking at. Delta3 makes a point about transmission efficiency which is fair enough but his numbers come from... well, the top of his head probably.

A coal-fired power station is several times more efficient than a coal-fired steam engine, easily overcoming the transmission loss from high-tension cables. The same goes for any other type of primary fuel. The fact that batteries are a 'secondary' power source is simply not a problem from an efficiency point of view.

His point about electric car development is partially true. Ford and GM are busy recalling and scrapping the electric vehicles they designed for California beacause they're too good.

Instead we have the idea of hydrogen as a scondary fuel. Now this is a seriously flawed, and plenty of people believe the fuel-cell is a deliberate diversion by the oil industry.

Further reading at EV World article

Hoss 1's story about the Orlando experiment is the best lead so far.... care to tell us more, Hoss 1?

Benet

Benet,

I saw your posting for the first time last night. I am in the camp that say that present battery technology is what limits your idea from being applied.

I did have a look on the net to see what the performance figures for rechargeable batteries were. Some recent research anticipates an energy density of about 1000Kj/Kg (a very rough guide).

Suppose an R22 needs 90 hp (or 67 Kw) of power to cruise and supposing these batteries weigh what a full load of fuel would weigh in an R22: 81 Kg. Then you have on board 81000 Kj of energy which your motor would use at a rate of 67 Kj per second. You have power to cruise for 81000/67=1209 seconds or just over 20 minutes.

A seven or eightfold increase in battery energy density is needed before the idea becomes practical, I would guess.

Ok, so bypassing the flat/round electron arguments on this one (although personally I'd think flat ones would be more practical purely on storage grounds), the main restriction point on this one would seem to be battery technology.
So.... in a car, the battery is used to provide energy to operate the starter and then as a constantly topped up reservoir for all other electrical usage (assuming the alternator is working).
So (2)... why not have this E22 or R22e set up to have two drive motors (both driving a main gb as per a normal twin) and also driving a pair of (or just one) high output alternators. You'd still have batteries, but only sufficient storage to run up to initial speed until the alts took over and also provide say 5 mins power should both alts fail - thus enough for say 2 mins emergency manouvering or to get safely into auto.
Granted, the oil companies would do everything possible to avoid the idea getting anywhere, but once it got certified, even with a slightly higher initial cost, I could see them selling very well indeed..... no fuel costs, massively reduced engine maint costs... the pollution bonus, the noise bonus. Potentially, could do masses for the whole helo industry.

But that's just my 2 penneth, not that I don't love the smell of avtur in the morning.... cos I don't:*

'Empty weight' is the bane of rotorcraft.
 

Decreasing the weight of the fuselage, the rotor and the power-train by using plastics (composite construction) will be a significant improvement.

Combining this with the previously mentioned plastic battery, and one can envision the eventual possibility of the fuselage being the battery.

:8

Maybe I'm being too narrow minded, but I just don't think you will ever see batteries (stored energy using inverters or whatever similar gadget) as the primary power source for rotorcraft. You might get away with that for fixed wing, because they can turn the prop on and off when needed (& they can generally carry more weight). If it's going to happen in a rotorcraft, my money is on a hydrogen system that provides energy directly to a fuel cell, which provides power for the electric motor and systems. Again, fuel cell technology is coming along nicely... how to carry enough hydrogen (safely) is the real problem.

Heck, you can purchase a retail version of a fuel cell power generator that will provide 1,000 watts of electricity as long as hydrogen gas is supplied. It's quite, nearly maintenance free, and was designed to run INDOORS (you don't have to worry about CO poisoning in the cockpit)...

http://www.fuelcellstore.com/cgi-bin...94/product=393

http://www.ballard.com/popup_airgen_virtual_tour.htm

So, how can you carry enough H2 fuel (read throughput) for the larger systems (currently used in Ford & Chrystler protypes)? For rotorcraft, it just can't be done... today. That's just one challenge. With this kind of configuration, it is likely that you will need a complicated transmission to maintain RRPM in all fight regimes... simply adding more power or less power might not be an option anymore.

benet,
you are pretty far off in all of your opening premises:

- Electric motors are a lot lighter than piston engines

Not at all true. Typical piston engines are about 1/3 the weight of an equivilent electric motor. For example, a 150 HP electric motor weighs 1350 lbs, while a 180 HP Lycoming weighs 257 lbs. Even if we assume that we could get an electric motor to trim 3/4 of its weight, it would still be far heavier than a piston engine.
here are some facts
http://www.lycoming.textron.com/main...uide/heli.html

http://www.tecowestinghouse.com/PDF/Prem_Eff_ODP(05.03).pdf

- Electric motors are way more efficient
Hardly electric motors are not engines, they are actually a form of transmission. they need raw energy to work, unlike engines, which create energy in their process. Since you don't include how the electricity is made into your assumption, you believe that the electric motor wastes less, but that is actually quite false. since someone somewhere had to make the electricity, you must count that inefficiency in, and so far, no total process is much more efficient than a simple engine. Fuel cells are the exception, and should they work out in high capacity, there might be parity in the efficiency, but of course, the weight of the fuel cell must be counted in, and they are quite heavy in high power designs, so far.

- Startup, shutdown and carb icing wouldn't be problems any more
True, but then we'd have "relay freeze" or "spark jump" or some other set of problems! Remember what the side of Apollo 13 looked like when the fuel cell exploded?

- There would be a lot less moving parts, and reliability would be increased
See Above!

- The end result would be eco-friendly and very cheap to run!
Eco-Friendly, right. And cleaner clothes, smoother white teeth, with that fresh lemon scent!

The solution to electric air vehicles is very far off, mostly weight problems, mostly in the energy storage area. Fuel cells are the best solution, along with very light weight motors and lots and lots of development time and money.

A more likely solution is to make cheap electric power with reactors (fusion, perhaps) use the electricity to split water into hydrogen, compress it into liquid and run gas turbines in the flying machines on that hydrogen with zero emissions

air combustion?
 

why not just compressed air? diving below, is it 80 metres?, they breath helium (or a mixture) so the air doesnt explode. this would be around 90 times the attmesphere. would need a good stroke on the crank i spose:confused: or maybe it takes more energy to compress the air than the explosion makes?? :ok:

vorticey,

Just storing energy won't work, because the aircraft needs so much of it. If you squeeze air into a bottle and then let it out into an engine, you get less than you put in. If you bring some gasoline, you get a tremendous return on its weight. For example, a pound of air squeezed to 90 atmospheres has about 2.6 million ft-lbs of stored energy in it. If it were used in 1 minute, it has a total of 78 Horsepower for that minute. If a pound of gasoline were compared, it has 14 million ft-lbs of energy in it, and delivers 424 Horsepower if burned in 1 minute.

In other words, fuel is about 5 times more weight efficient when compared to stored air. And we didn't figure in the weight of a compressed bottle as compared to a fuel tank. My guess is the bottle would have to be 5 to 10 times heavier than the fuel tank, a further penalty.

You have also pointed out why electricity is so poor in flying machines. Recall that the electric motor needs to have energy delivered to it, so it needs to be fed those enoumous amounts of energy to make the power, and that energy is hard to come by.

PS they breath helium at great depth because of nitrogen narcosis, not because of explosions. At high pressure, nitrogen is an anesthetic and makes you high! Helium only makes you talk like Donald Duck.

Nick, I have to disagree with you here.

I wasn't able to download the PDF you linked to, but you're definitely looking in the wrong place for your electric motor. Perhaps the one you found was designed for elevator installations? The one I found here delivers a lot more power than your Lycoming and weighs 180lb including its cooling system so don't forget to take off the squirrel cage!

I know my batteries are going to be heavier than a fuel tank. But I'm also taking out both gearboxes, the mechanical drive shaft, the oil cooler, the clutch, the alternator, the starter motor and any other IC-related things I can think of...

I don't have the slightest intention to use fuel cells. They have a very poor energy density and the usage problems you describe. Nor would I use hydrogen - current storage methods involve a high-pressure tank storing liquid hydrogen, and the energy density of the tank + hydrogen is way below the current best offered by batteries. Chemical batteries are the closest thing to gasoline, as described at the EVWorld link in my previous post.

You're right about electricity being a 'secondary' power source; something has to burn or turn somewhere to generate the electricity. You overestimate the transmission losses, which leads you to conclude that a primary power source is more efficient than a chain which includes stored electricity. This would be true if small internal combustion engines were at all efficient. Do the math: 65% efficiency in a power station vs 10-15% efficiency in a small IC engine. There's a lot of leeway for transmission losses in my electricity chain!

Keep up the counter-arguments though...

Benet

Good data, Benet, but bad math. That 180 lb motor you found is nice, but it is only 70 HP continuous power!

Also, no power plant on the planet has more than 50% efficiency (unless they repealed Carnot's cycle), most are around 35% or so. Some experimental plant models get 40% as do fuel cells.

The total system efficiency is the product of the 35% (power plant) x the 90% transmission x the 86% of the motor for a net 27%, about the same for a good gas powered piston engine. My Honda a few years ago was 24% efficient on the highway at 60mph!

And that does not include the massive battery system, nor the 350 lbs for the motor (2 x the 70 HP motor you found).

Still a long way off, and not closing, I think. But a good fact finding debate, nonetheless!

There are electric motors using rare earth magnets and brushless commentators that have a horsepower to weight ratio of one-to-one. They turn at around 60,000 rpm

Also, there is a Russian design of gear reduction that has ratios of around 250:1, with only two or three gears and low friction loss.

OK Dave, now we know. Your dreams are filled with an electric synchropter with three gears in its 60,000 rpm transmission, and a fiber optic electric cord 200 NM long!

I still see Nichole Kidman when I close my eyes!

Hi Nick,

I'm sure you agree that electricity will eventually replace fossil fuels. Naturally, this will require significant improvements in the means of producing the electrical energy, storing this energy, and converting this energy to physical motion.

Some of this technology should eventually transfer from mass-produced land vehicles to air vehicles. But, probably no electric synchropter in our lifetimes.

Best that helicopter manufacturers buy the energy storage and conversion devices from outside sources. Hell, you know better than I that helicopter companies could better spend their limited R & D funding on improving the rotor ( excuse me ~ two rotors :D ).


P.S. If a dream is a type of storage device, like a battery is, would a dream about Nicole Kidman be a wet battery or a dry one?
http://www.unicopter.com/Temporary/sexy_eyes.gif

dave,
The energy technology dreams of the future all rest on "deus ex machina" of fusion reactors, sinced everything else we have tried really doesn't work very well. Actually, nucular fission does work well, but technologists get an F in public relations, so we are in the situation we are in as a result.

Once we get good cheap energy from fusion, it will be the source, and electric distribution will dominate the land side. I think liquid hydrogen gas will serve as the fuel source for transport devices in air and space, since the weight energy density is so good. Fuel cells might get very good, too, but all they would do is re-combine the hydrogen and oxygen that we had split earlier.

Regarding Nichole, she sent me this yesterday:

http://www.s-92heliport.com/nichole.jpg

A bit of trivia
 

Nick.

You're right about public relations.

France gets 70% of its electrical energy from nuclear plants. They have (maybe no longer) weekly public tours of a shut down facility and also a separate tour an operating facility. Even foreigners could take the tour if they showed their passport.


Good picture. :ok:

Imagine your electric R22 getting struck by lightning.
Now watch that sucker whizz across the sky.

The future of the helicopter is electric.
 

I keep banging on about this in other threads for aviation in general. But it makes extra muchness of sense for helicopters. And until batteries are where they need to be, a hybrid solution is very interesting.

Let's toy with the idea for a second.

Brushless motor or motors run the main rotor and anti-torque. You have small battery that can power heli at full power for about 10 minutes. You have turbine APU that runs a brushless gen that recharges the batteries during the flight and/or can directly power the brushless motors. Look at the benefits:

1. No gearbox needed, direct drive on the shaft. Weight savings, reliability improvements.
2. Brushless motors give more power per weight than any other engine (easily about 8-10Kw/kg - beat that gas turbines), which saves weight further.
3. Anti torque is direct driven by a dedicated brushless and rpm only, no complicated shafts, no blade actuation.
4. Brushless motors are pretty much only limited by bearing life, so maintenance should become very cheap.
5. APU gen set can be made cheaper and to lesser standards and be overhauled less frequently because if it should fail, you have 10 minutes on battery power to get safely down.
6. For HEMS and other time critical operations, startup and shutdown would be a 10 second affair. Just power up and go on battery power, then start the APU when you're airborne. That time could save lives.
7. No over temps, no over-torques, no cool downs, no altitude penalties, no shock cooling, no performance losses from tail, no LTE, etc.
8. Much less noisy.
9. Training could be done on batteries alone that get swapped and recharged, which would dramatically lower the cost of training. At least at the home field.
10. Fadecs and governing becomes a piece of cake, as all brushless motors keep the rpm you tell them to keep, regardless of load. That's how you drive them electronically. It's literally a $10 circuit.

I was thrilled to hear about Sikorskys 300CB that they converted to electrics and flew before Oshkosh. It can only fly for 15 minutes at the moment at full power, but it's a great start. Battery capacity has steadily increased over the years and with the new nanowire silicon batteries in development with 10 times more capacity, it could be all over for fossil fueled aviation much quicker than we think. Mind you, I'm no environmental nut, I just welcome all the benefits of electric power. It has virtually no drawbacks and is perfectly suited for aviation.:D

But let's say one of the big manufacturers presented such a ship tomorrow, the certification processes are not in place. It's going to take FAA and EASA decades before they get on the ball, is my suspicion. That's probably going to be the funnel.

Even a R22 according to RHC needs about 60-70kW to maintain level flight at cruise speed. To deliver that for 10 minutes you need at least a 10,000Wh battery - about 200 times the capacity of a big laptop battery, or 20 car batteries. For a R22. 10 minutes.

Thats why the CB300 demonstrator can fly only for 15 minutes.

Saves weight further? The Gen/Electric Motor/battery are replacing a gearbox, so weight is only saved if they are lighter than the GB.
The turbine is still needed.
Also, what would a brushless motor look like that can deliver, say, 200kW at 400RPM (for main rotor direct drive of a 5 seat helicopter), and would it really be light?
And imagine the battery for THAT.

only the gearboxes are replaced in your example, the turbine is still there.


Why no altitude penalties? Again, the turbine is still there and required. Same with the noise.

An all electric helicopter would be a great thing for many reasons - but, given the poor energy efficiency of rotary wing flight in general, and the weight problems that come with it, I believe helicopters will be amongst the last vehicles on earth to be succesfully converted to battery power. And that will happen only after some massive breakthroughs in battery technology.

While I agree that an electrically-powered helicopter offers many advantages, and I personally think the hybrid idea is jolly exciting, it is important to remember that most electricity is generated from fossil fuels. Assuming battery technology improves massively, and we can store a useful amount of power in a usable weight, that battery still needs charging - where does that electricity come from? If it's out of the wall socket, ultimately it'll come from fossil fuels.

The other thing to bear in mind (and this is something the current crop of electric cars are running up against) is that you're probably going to need a fair amount of power to run your electric helicopter. Assuming you have somewhere to store said power onboard (whizzy batteries or whatever), you still have to get it in. The capacity of the average household outlet might get you fully charged up in a couple of days, perhaps a week or so - not exactly convenient (endurance of, say, 3 hours per week)! Assuming you have access to a properly meaty supply, and the various connectors and lines to get it to your pad, you're effectively tied to a single base (almost nobody else will have the necessary setup). The hybrid idea is nice, as the necessary infrastructure is already in place, but for fully 'leccy choppers to really take off (ha ha), you need quite a lot of infrastructure upgrade.

Sadly, as much as I'd love to see a proper helicopter based around electric motors, I think there's a bit of a chicken and egg problem here. Any suggestions as to how that can be overcome?