Air-Car, Anyone?
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Moller International, Inc. ... today announced it has found that ethanol fuel is an excellent fuel for most applications using its Rotapower(R) engines. ... Moller's engine is considered very powerful for its weight, and relatively low cost. It is nearly vibrationfree and generates very low levels of harmful emissions. Considerable interest has been shown in its potential application in motorscooters, recreational and utility vehicles as well as hybrid cars and portable power generators.
The Rotapower(R) engine is a multifuel compatible engine and in testing various fuels including gasoline, diesel, natural gas, and various types of alcohol, MI found that their engine ran coolest and cleanest on ethanol. In addition, the already outstanding emissions characteristics of the chargedcooled rotary engine designs were further enhanced with the use of ethanol.
The Rotapower(R) engine is a multifuel compatible engine and in testing various fuels including gasoline, diesel, natural gas, and various types of alcohol, MI found that their engine ran coolest and cleanest on ethanol. In addition, the already outstanding emissions characteristics of the chargedcooled rotary engine designs were further enhanced with the use of ethanol.
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This "Rotapower" aka Freedom engine 
is based on the wankel engine, conviniently its logo is the wankel engine rotor.
Check it out ---> http://www.moller.com/rp.htm
I agree somewhat with FH1100 Pilot in that we need dreamers because who knows what future holds. But as for now, I somehow doubt the moller car has a great future...but hey who knows. Also the latest designs make it look like a standard aircraft more and more.
is based on the wankel engine, conviniently its logo is the wankel engine rotor. Check it out ---> http://www.moller.com/rp.htm
I agree somewhat with FH1100 Pilot in that we need dreamers because who knows what future holds. But as for now, I somehow doubt the moller car has a great future...but hey who knows. Also the latest designs make it look like a standard aircraft more and more.
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Originally Posted by Ioan
What I am saying though is that I hope it DOES work. New ideas are never popular. This company has made big claims and who knows whether it'll ever live up to them; I hope it does. In 1903 did anyone believe that a hundred years later over a million people would be airborne at any given moment?
The lastest Moller concept has grudgingly accepted the same guiding principle, that all other aero engineers hold dear, by sprouting a pair of wings. This still leaves transition or flight at low heights and speed to consider. Eventually it will look like a helicopter...
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Ioan,
Admonishing this group because you have "hope" presumes, incorrectly, that we do not. It also presumes that "thoughts" and "knowledge" somehow hamper the search for a future flying machine. Let me also say that it is not only foolish, it exposes your lack of intellectual curiosity. Beware of any argument you make that starts with, "I don't know a thing about what we are talking about...."
Our hopes are often abused by those who know the real answer but hide it from us. I also hope we find better systems, too, but I don't allow that to stop asking some cold, hard questions about the physics involved.
The tiny rotor disks of the Moller air car make it a power-hungry beast, note that on the one model where he actually tells you how much HP he needs, he shows that it need 1/2 horsepower for each pound of gross weight. A light helicopter needs between 1/10. That means (for someone who says "I know nothing about this aircraft") that all you have to do is ask the charlatan, "How much power does it need?" and hear him dance around before he says, "Five times more than a helicopter."
A simpleton, even one with "hope" would then know that Moller's car is impossible, since he must install 1200 Horsepower in a vehicle that weighs 2400 lbs including engines, fuel, structure. The 2 cycle engines he says he uses (or the rotary engine he also mentions) weigh about 1 pound per horsepower, and they consume fuel at a rate between 25% and 100% faster than a regular 4 cycle engine.
The technically challenged reporter could not grasp how simple it would be to get Moller to tell the truth, that half the weight of his miracle car is engine, and the other half is fuel, leaving nothing for structure or people.
Admonishing this group because you have "hope" presumes, incorrectly, that we do not. It also presumes that "thoughts" and "knowledge" somehow hamper the search for a future flying machine. Let me also say that it is not only foolish, it exposes your lack of intellectual curiosity. Beware of any argument you make that starts with, "I don't know a thing about what we are talking about...."
Our hopes are often abused by those who know the real answer but hide it from us. I also hope we find better systems, too, but I don't allow that to stop asking some cold, hard questions about the physics involved.
The tiny rotor disks of the Moller air car make it a power-hungry beast, note that on the one model where he actually tells you how much HP he needs, he shows that it need 1/2 horsepower for each pound of gross weight. A light helicopter needs between 1/10. That means (for someone who says "I know nothing about this aircraft") that all you have to do is ask the charlatan, "How much power does it need?" and hear him dance around before he says, "Five times more than a helicopter."
A simpleton, even one with "hope" would then know that Moller's car is impossible, since he must install 1200 Horsepower in a vehicle that weighs 2400 lbs including engines, fuel, structure. The 2 cycle engines he says he uses (or the rotary engine he also mentions) weigh about 1 pound per horsepower, and they consume fuel at a rate between 25% and 100% faster than a regular 4 cycle engine.
The technically challenged reporter could not grasp how simple it would be to get Moller to tell the truth, that half the weight of his miracle car is engine, and the other half is fuel, leaving nothing for structure or people.
"Just a pilot"
I have hope
I hope neither model is ever sold to the public. My personal vision of eternal perdition is the general population applying it's navigational and traffic problem solving skills to 3 dimensions, moving at 300 mph- especially computer controlled.
That sounds a bit Luddite, but take a look, next drive, at how many drivers are multi-tasking (eating, phoning, reading, watching movies....) at 45 mph. I don't want more poorly trained drivers in the airspace with the illusion that "george" is flying. And, most urban areas can't adequately plan traffic in 2 dimensions. "SUVs in space" is a very bad idea. Thankfully, it'll never happen. At least, until the current rocket belt boom bottoms out...
That sounds a bit Luddite, but take a look, next drive, at how many drivers are multi-tasking (eating, phoning, reading, watching movies....) at 45 mph. I don't want more poorly trained drivers in the airspace with the illusion that "george" is flying. And, most urban areas can't adequately plan traffic in 2 dimensions. "SUVs in space" is a very bad idea. Thankfully, it'll never happen. At least, until the current rocket belt boom bottoms out...
Devil49, as long as the FAA (Fockers Against Aviating or something like that) still controls the airspace in the U.S. above ten feet or so, I seriously doubt whether we'll have many "drivers" buzzing around in Moller whatevers. So fear not, my Luddite friend.
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as long as the FAA (Fockers Against Aviating or something like that) still controls the airspace in the U.S. above ten feet or so
As to the idea of people flying about doing school runs in weapons like this... No thanks! It's bad enough now as to the driving standards.
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Nick I found your reply there fairly offensive. I did not ever intend to 'admonish this group' - nor can I find anything which I've written which would suggest that intention.
I am curious about this aircraft. How intellectual or not that curiosity is is something I'd find hard to quantify. When I stated my lack of knowledge of this design I was merely attempting honesty and to indicate that the numbers and information I'd posted were the result of the sources I listed, rather than any new or detailed data regarding the aircraft.
For what it's worth though, in my opinion (and obviously contrary to yours) thoughts and knowledge do have a significant effect of the research and development of new technology. It takes people who're willing to investigate ideas that don't work to produce designs that do... and I have no problem admitting to anyone that I admire Moller for that if for nothing else.
I have no desire to argue with you or anyone else here. I understand from your background and the data you've posted that you're far better informed on this aircraft than I. If it doesn't work yet... I'm just happy for them to continue trying
I am curious about this aircraft. How intellectual or not that curiosity is is something I'd find hard to quantify. When I stated my lack of knowledge of this design I was merely attempting honesty and to indicate that the numbers and information I'd posted were the result of the sources I listed, rather than any new or detailed data regarding the aircraft.
For what it's worth though, in my opinion (and obviously contrary to yours) thoughts and knowledge do have a significant effect of the research and development of new technology. It takes people who're willing to investigate ideas that don't work to produce designs that do... and I have no problem admitting to anyone that I admire Moller for that if for nothing else.
I have no desire to argue with you or anyone else here. I understand from your background and the data you've posted that you're far better informed on this aircraft than I. If it doesn't work yet... I'm just happy for them to continue trying
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Ioan,
Don't take offense, none was intended, but certainly you did critique those of us who expressed technically based criticisms.
For starters, "New ideas are never popular," as if popularity somehow creating lift, and as if we were negative because of "popularity".
"Who knows how well it'll work..." when several very capable people had already posted the facts, and as if we cannot read the spec sheets and see then need for 5 times the horsepower of a helo.
My suggestion is that you ask "why" and not say "I hope" to both Moller and those of us who can better examine his concept than you can. Who knows, you might learn something, and you might uncover a weakness in our points or Moller's. I do suggest a quick search under "disk loading" for how rotors consume power, because you are obviously one of those fellows who thinks there is a new rotor around the corner awaiting a gutsy "researcher" that can harness a fly's power to lift the London Bridge. The physics of momentum transfer don't work that way.
Don't take offense, none was intended, but certainly you did critique those of us who expressed technically based criticisms.
For starters, "New ideas are never popular," as if popularity somehow creating lift, and as if we were negative because of "popularity".
"Who knows how well it'll work..." when several very capable people had already posted the facts, and as if we cannot read the spec sheets and see then need for 5 times the horsepower of a helo.
My suggestion is that you ask "why" and not say "I hope" to both Moller and those of us who can better examine his concept than you can. Who knows, you might learn something, and you might uncover a weakness in our points or Moller's. I do suggest a quick search under "disk loading" for how rotors consume power, because you are obviously one of those fellows who thinks there is a new rotor around the corner awaiting a gutsy "researcher" that can harness a fly's power to lift the London Bridge. The physics of momentum transfer don't work that way.
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Moller is good at spending other peoples money. I believe he had some problems with the Securities and Exchange Commission.
The idea of a flying car is the most popular news story to run as a cover story according to Popular Science magazine. The problem is: there are no vtol flying cars. But it remains a good way to scam investers.
The idea of a flying car is the most popular news story to run as a cover story according to Popular Science magazine. The problem is: there are no vtol flying cars. But it remains a good way to scam investers.
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OK SOME fair points there.
I'm not some daydreaming loony though believe it or not. At least I like to think not!
I personally believe that the breakthrough will come not with some new rotor system (there's only so many ways you can propel air after all), but through the powerplants, where there is a lot of scope for improvement. Graviman - I see where you're coming from. The problem is Moller have obviously decided they want a high speed aircraft, and bar having a separate helicopter-like VTOL rotor, they've correctly in my opinion chosen to accept the lower efficiency during that stage of flight to increase its efficiency at high speed. Even if it does mean that during a vertical takeoff it uses 5x the power of a helicopter. Harriers don't like hovering either, but it was an incredibly successful aircraft which was capable of it, and which was designed almost 50 years ago.
At the moment there's a lot of interesting research going on regarding alternative future power sources - hydrogen ICEs, and electricity storage for example. Electric motors in particular are far more energy efficient than fossil fuel powerplants will ever be; the problem as usual is reducing the weight while increasing the energy storage capacity. The boom in mobile electronic devices (phones, laptops etc) the last decade or so has prompted manufacturers to invest in battery research which means they're getting lighter and more efficient all the time... possibilities there maybe.
There's also the possibility of 'energy regeneration' (horrible term I know) through effectively air braking, and perhaps some future methods of wireless energy transmission such as those discussed here http://news.bbc.co.uk/1/hi/6129460.stm (more than simple energy induction) - all ideas which one day may go some way to getting future aircraft off the ground.
Devil 49 - I hope I don't sound like I'm playing devil's advocate here - but to go back to history again in 1865 the UK parliament passed an act creating a speed limit of 4mph in the country and 2mph in towns for what they called 'self-propelled locomotives'. It also required a bloke to walk 60 yds in front with a red flag or lantern to enforce the speed limit and warn anyone ahead of the approaching machine.
Cars of then and cars of today… time moves on.
The technology already exists for a computer in a car to autonomously recognise a huge range of potential dangers (driver falling asleep, water on the road, collision ahead, vehicle on collision course, etc), carry out the appropriate action (apply brakes, warn driver), and then transmit details of the hazard to systems in other cars so they have increased 'awareness'.
GPS has simplified navigation to 'I'm here - I'm going THERE – follow this line', FMCs can tune, identify, display and navigate around a whole range of navaids with almost no pilot input...
I can't see the public getting their hands on Skycar-like machines at any point in the near future, no. But my point is never say never
I'm not some daydreaming loony though believe it or not. At least I like to think not!
I personally believe that the breakthrough will come not with some new rotor system (there's only so many ways you can propel air after all), but through the powerplants, where there is a lot of scope for improvement. Graviman - I see where you're coming from. The problem is Moller have obviously decided they want a high speed aircraft, and bar having a separate helicopter-like VTOL rotor, they've correctly in my opinion chosen to accept the lower efficiency during that stage of flight to increase its efficiency at high speed. Even if it does mean that during a vertical takeoff it uses 5x the power of a helicopter. Harriers don't like hovering either, but it was an incredibly successful aircraft which was capable of it, and which was designed almost 50 years ago.
At the moment there's a lot of interesting research going on regarding alternative future power sources - hydrogen ICEs, and electricity storage for example. Electric motors in particular are far more energy efficient than fossil fuel powerplants will ever be; the problem as usual is reducing the weight while increasing the energy storage capacity. The boom in mobile electronic devices (phones, laptops etc) the last decade or so has prompted manufacturers to invest in battery research which means they're getting lighter and more efficient all the time... possibilities there maybe.
There's also the possibility of 'energy regeneration' (horrible term I know) through effectively air braking, and perhaps some future methods of wireless energy transmission such as those discussed here http://news.bbc.co.uk/1/hi/6129460.stm (more than simple energy induction) - all ideas which one day may go some way to getting future aircraft off the ground.
Devil 49 - I hope I don't sound like I'm playing devil's advocate here - but to go back to history again in 1865 the UK parliament passed an act creating a speed limit of 4mph in the country and 2mph in towns for what they called 'self-propelled locomotives'. It also required a bloke to walk 60 yds in front with a red flag or lantern to enforce the speed limit and warn anyone ahead of the approaching machine.
Cars of then and cars of today… time moves on.
The technology already exists for a computer in a car to autonomously recognise a huge range of potential dangers (driver falling asleep, water on the road, collision ahead, vehicle on collision course, etc), carry out the appropriate action (apply brakes, warn driver), and then transmit details of the hazard to systems in other cars so they have increased 'awareness'.
GPS has simplified navigation to 'I'm here - I'm going THERE – follow this line', FMCs can tune, identify, display and navigate around a whole range of navaids with almost no pilot input...
I can't see the public getting their hands on Skycar-like machines at any point in the near future, no. But my point is never say never
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Iaon,
You are quite correct, it will not be the lift generator that will be the stunning breakthrough, but rather the power source. This has been true for all aviation breakthroughs.
The Wrights made an engine at 10 lbs per HP, and that achievement alone was enough to make them famous, even had full 3 axis control waited a few years.
The helo itself had to wait until engines came closer to 1 lb/HP, since Igor Sikorsky's 1939 rotor was almost as efficient as his 1909 rotor and also todays rotors (in the hover.) The spread between the hover efficiency is from the first helo to today is about 20%, while power plant weight efficiency has gone up by a factor of 100.
The turbine engine made the tilt rotor possible, with 10 HP per pound.
What Moller needs is a turbine's power to weight (in a very small package), but a piston's fuel efficiency, a tall order. Beamed energy with electric motors is certainly a possibility sometime in the future, but that break through will give all boats a lift, and helos will really get efficient by that route!
None of this gives Moller any credit, he knows the technical facts that we are bandying about, has known for decades, but he never mentions it to the press or investors when he should. He turns hope into nice houses and impressive business cards, I am afraid.
You are quite correct, it will not be the lift generator that will be the stunning breakthrough, but rather the power source. This has been true for all aviation breakthroughs.
The Wrights made an engine at 10 lbs per HP, and that achievement alone was enough to make them famous, even had full 3 axis control waited a few years.
The helo itself had to wait until engines came closer to 1 lb/HP, since Igor Sikorsky's 1939 rotor was almost as efficient as his 1909 rotor and also todays rotors (in the hover.) The spread between the hover efficiency is from the first helo to today is about 20%, while power plant weight efficiency has gone up by a factor of 100.
The turbine engine made the tilt rotor possible, with 10 HP per pound.
What Moller needs is a turbine's power to weight (in a very small package), but a piston's fuel efficiency, a tall order. Beamed energy with electric motors is certainly a possibility sometime in the future, but that break through will give all boats a lift, and helos will really get efficient by that route!
None of this gives Moller any credit, he knows the technical facts that we are bandying about, has known for decades, but he never mentions it to the press or investors when he should. He turns hope into nice houses and impressive business cards, I am afraid.
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That's wrong then obviously. Though you do have to wonder, if someone invests a huge amount of money into these vehicles without researching it enough to realise he ISN'T getting anywhere with it, well it's their loss really! At least there's something achieved if there is some R&D carried out on the aircraft and engines.
And P.S. talking about engine efficiency, you've reminded me of one of those random facts - although the engines used on the wright flyer were remarkably heavy for the power produced, the propellors were in the region of 75 - 80% efficient. Considering that modern wooden ones reach roughly 85% I find that amazing
And P.S. talking about engine efficiency, you've reminded me of one of those random facts - although the engines used on the wright flyer were remarkably heavy for the power produced, the propellors were in the region of 75 - 80% efficient. Considering that modern wooden ones reach roughly 85% I find that amazing
I understand the concept of total efficiency (motor, rotor etc)
(I've tried to phrase this question in laymans terms but suspect its caused more confusion as a result...)
Basically, what is the specific fuel consumption per kW output of a turbine vs a comparable four stroke reciprocal engine?
(I've tried to phrase this question in laymans terms but suspect its caused more confusion as a result...)
Basically, what is the specific fuel consumption per kW output of a turbine vs a comparable four stroke reciprocal engine?
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Ioan,
Your prop vs engine comparison is a perfect illustration of what I said, the air mover stuff has made small strides while the engine power to weight has made amazing strides. This is because the prop/rotors are merely converting momentum, a fairly low-tech task. Engines do amazing backflips to convert chemical energy into power.
The Wright engine was very heavy relative to today's numbers, but it was about 10 times the weight efficiency of anything that had previously been made. It was a wonder, but it was 100 times heavier than the engine in a Black Hawk, per horsepower.
mini,
The typical turbine is inefficient in terms of power to fuel burn when compared to a piston. Efficiency is almost purely driven by the internal temperature that the engine produces, because the most efficient engine has a big delta temp from its power cycle to the outside (so therefore there is a big "natural" heat rejection that is the thermodynamic equivalent of voltage, a big push for each package of hot gas).
A turbine usually is operated at lower power and temperatures to allow long life, and also to keep the highest power (and temperature) in reserve for emergencies. Pistons burn their fuel at the hottest temp all the time (they can because their valves are tucked into the head to conduct away heat and shield them from the hottest temps), and they increase their power output by increasing rpm to process more fuel per second.
Some numbers:
a good turbine burns .6 to .8 lbs of fuel per hour per HP in cruise, and .5 to .6 at takeoff (more efficient)
A regular piston engine burns about .41 to .47 lb/hp/hr
source:
http://www.jet-engine.net/civtsspec.html
http://en.wikipedia.org/wiki/Specific_fuel_consumption
Your prop vs engine comparison is a perfect illustration of what I said, the air mover stuff has made small strides while the engine power to weight has made amazing strides. This is because the prop/rotors are merely converting momentum, a fairly low-tech task. Engines do amazing backflips to convert chemical energy into power.
The Wright engine was very heavy relative to today's numbers, but it was about 10 times the weight efficiency of anything that had previously been made. It was a wonder, but it was 100 times heavier than the engine in a Black Hawk, per horsepower.
mini,
The typical turbine is inefficient in terms of power to fuel burn when compared to a piston. Efficiency is almost purely driven by the internal temperature that the engine produces, because the most efficient engine has a big delta temp from its power cycle to the outside (so therefore there is a big "natural" heat rejection that is the thermodynamic equivalent of voltage, a big push for each package of hot gas).
A turbine usually is operated at lower power and temperatures to allow long life, and also to keep the highest power (and temperature) in reserve for emergencies. Pistons burn their fuel at the hottest temp all the time (they can because their valves are tucked into the head to conduct away heat and shield them from the hottest temps), and they increase their power output by increasing rpm to process more fuel per second.
Some numbers:
a good turbine burns .6 to .8 lbs of fuel per hour per HP in cruise, and .5 to .6 at takeoff (more efficient)
A regular piston engine burns about .41 to .47 lb/hp/hr
source:
http://www.jet-engine.net/civtsspec.html
http://en.wikipedia.org/wiki/Specific_fuel_consumption
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Not convinced about power transmission by EM-fields, although the MIT researcher is really discussing a transformer with seperable coils rather than using radio. Studies once indicated that high frequency noise generated by computer switch mode power supplies could travel along power lines to be reradiated, and was linked statistically with cancer for those living near power lines. Recent CE regulations have done a lot to clean up power supplies:
http://en.wikipedia.org/wiki/Electro...r_transmission
There are many problems which make remote power supply to a helicopter impractical. The main ones are how to direct all of the energy accurately to a point, how to stop everything around being fried (including crew), and how to even approach reasonable efficiency. IMHO it just won't happen.
http://en.wikipedia.org/wiki/Electri...r_transmission
The best immediate hope for improved power/weight and efficiency for <500 SHP is the latest trend (with VW in the lead) for very high turbo boost piston engines. Both avgas, and avtur diesel engines would benefit. You get the benefit of piston combustion's high efficiency and turbines large air flow rates for a given engine size/mass. The engine needs to be designed to handle extreme pressures, but new materials and surface coatings are allowing this. Forget 2-strokes, wankels, and all the other weird variations - all of them spew out oil like there was no EPA tomorrow.
http://en.wikipedia.org/wiki/Turbocharger
Nick, IMHO the next power revolution will come from the development of direct thermal conversion technology. It already looks competetive at this early stage (estimate >40kW/kg), which means that with development it will eventually do away with both fuel cells and thermodynamic engines.
http://www.eurekamagazine.co.uk/arti...l-engines.aspx
http://en.wikipedia.org/wiki/Electro...r_transmission
There are many problems which make remote power supply to a helicopter impractical. The main ones are how to direct all of the energy accurately to a point, how to stop everything around being fried (including crew), and how to even approach reasonable efficiency. IMHO it just won't happen.
http://en.wikipedia.org/wiki/Electri...r_transmission
The best immediate hope for improved power/weight and efficiency for <500 SHP is the latest trend (with VW in the lead) for very high turbo boost piston engines. Both avgas, and avtur diesel engines would benefit. You get the benefit of piston combustion's high efficiency and turbines large air flow rates for a given engine size/mass. The engine needs to be designed to handle extreme pressures, but new materials and surface coatings are allowing this. Forget 2-strokes, wankels, and all the other weird variations - all of them spew out oil like there was no EPA tomorrow.
http://en.wikipedia.org/wiki/Turbocharger
Nick, IMHO the next power revolution will come from the development of direct thermal conversion technology. It already looks competetive at this early stage (estimate >40kW/kg), which means that with development it will eventually do away with both fuel cells and thermodynamic engines.
http://www.eurekamagazine.co.uk/arti...l-engines.aspx
Last edited by Graviman; 2nd Sep 2007 at 08:42. Reason: General tidy up.