Eurocopter X3 hybrid
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the concept is pure...and in reality, very simple...
the rotors act as the 'wing' and supply lift only...
the props act for 'propulsion'
this brings the airframe to aerodynamic simplicity, yet compensates for the negative effects of increase rotor speed and drag...as the rotors are for lift only...
the rotors act as the 'wing' and supply lift only...
the props act for 'propulsion'
this brings the airframe to aerodynamic simplicity, yet compensates for the negative effects of increase rotor speed and drag...as the rotors are for lift only...
Just a brainstrom, is there some way to disengage and stop the push-props on ground without shutting down? Must be, because how are you going to let passengers go in and out with engine running, you dont just let em crawl around that food processor... they must have tought of that 
Just a brainstrom, is there some way to disengage and stop the push-props on ground without shutting down? Must be, because how are you going to let passengers go in and out with engine running, you dont just let em crawl around that food processor... they must have tought of that
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Originally Posted by jeffg
What happens when one of the props quits working and the other doesn't?
Originally Posted by rotorrookie
how are you going to let passengers go in and out with engine running
I/C
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If the cross-coupled (?) shafts fail, then you presumably feather the offending propulsor and kick-in a bunch of opposite rudder.
When you start thinking of the failure modes I don't know that you have a product that is really that much less complex than a tilt rotor.
Last edited by jeffg; 18th May 2011 at 19:14.
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Could one say the X2 has higher speed potential with contra-rotating rotors, where the X^3 would be more prone to retreating blade stall?
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Eurocopter has filed at least 4 additional US patent applications since the one mentioned in post #1 on this thread. These 4 applications relate to the flight-control of the craft. It appears that the X3 should have more safety options available than rotorcraft with single tail-rotors have.
It also appears that the short wings will contribute lift during forward flight. This will reduce the rotor's contribution to lift, which in turn reduces the detrimental effects of the reverse velocity region; such as negative lift and high profile drag.
Dave
It also appears that the short wings will contribute lift during forward flight. This will reduce the rotor's contribution to lift, which in turn reduces the detrimental effects of the reverse velocity region; such as negative lift and high profile drag.
Dave
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Helicopters: now with wings... 
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Helicopter with wings promises to change aviation world
BBC News 15 June 2011
Surging in from the west through one of Provence's many beautiful valleys, a peculiar looking aircraft is preceded by an unfamiliar sound.
The deep chugging rumbling of a conventional helicopter rotor is mixed with the loud whining noise of two wing-mounted forward-facing propellers, making it difficult to guess what is coming.
As the aircraft swoops over Montagne Sainte-Victoire, shaking the windows in holiday cottages and farm houses below, it becomes clear that this flying machine resembles nothing else in the skies.
Eurocopter's X3 rotorcraft - pronounced "X cubed" - is basically a chopper with wings, which will be seen for the first time by the public next week as part of the aerial displays at the Paris air show.
The prototype combines the versatility of a helicopter, by way of vertical take-off and landing, with the higher speed of a plane.
"It's exactly like a helicopter," says flight test engineer Dominique Fournier. "But as soon as you've taken off, it's exactly like a fixed wing aircraft."
Helicraft such as the X3 are set to revolutionise aviation, company executives say
Game changers
The X3 is one of the fastest rotorcrafts in the world, having achieved a cruising speed of 232 knots (430 km/h or 267 mph) during a test flight on 18 May.
Though not quite as fast as US rival Sikorsky's equally futuristic-looking but differently designed X2, which achieved a true air speed of 250 knots last September, the X3 has nevertheless made the prospect of ultra-fast helicopters going on sale within years much more likely.
Consequently, both helicopter companies describe their innovations as "potential game changers".
"The aerospace industry today has a new horizon," according to Sikorsky's president Jeffrey Pino. Eurocopter's chief executive Lutz Bertling says "it will be a totally different way of flying".
Mission capability
For the pilot and for passengers, the difference lies in the "very different sensation from flying this when compared with an ordinary helicopter", according to experimental test pilot Herve Jammayroc. "In the X3 we accelerate and decelerate horizontally."
And although the X3 is perhaps a more complex machine to build, "it is easier to fly than a conventional helicopter", Mr Jammayroc says.
For Eurocopter's customers, it is all about balancing costs with how quickly and how far the aircraft can travel.
Hence, although the X3 is at least 50% faster than conventional helicopters, "the key message is not speed", according to chief executive Mr Bertling.
"The key message is productivity," he says, insisting that the X3's greater size makes it a more versatile rotorcraft than Sikorsky's X2.
"We are not selling helicopters, we are selling mission capability," Mr Bertling says.
"If you can do it with a balloon or a fixed wing or a bicycle, you don't buy an expensive helicopter."
Experimental test pilot Herve Jammayroc says it is easy to fly the X3
Productive aircraft
Eurocopter's aim is to deliver an aircraft that increases cruising speeds by 50%, while limiting any resulting increase in costs to 25%.
"The target is a productive aircraft," Mr Bertling says.
"So 210-220-230 knots for us is quite reasonable. And 270-280 knots may be conceivable, but fuel costs get too high."
With the X3, the required technology is pretty much there, according to Eurocopter's chief technology officer Jean-Michel Billig, who is in charge of research and development.
"Today, we believe it should cost in the region of 20% more than a similar size helicopter in terms of cost of ownership," he says.
Fast helicraft such as the X3 are unlikely to replace conventional helicopters
Replacement programme
The X3 forms part of a broader restructuring of Eurocopter, which includes plans to replace its entire current offering of six different helicopter models.
"We have a road map to renew our current product family over the next 10 years," says Mr Billig.
A helicopter programme costs about 1bn euros ($1.4bn; £876m) per year and typically lasts for about six years, so it is a costly exercise.
The company is also working on more fuel-efficient models, such as helicopters powered by diesel-electric hybrid engines, or unmanned or optionally manned helicopters, even full-sized ones that carry passengers.
Improving safety, both in terms of reliable systems and crew awareness, and to reduce operating and maintenance costs, are also central tasks.
Eurocopter is preparing to replace its entire helicopter model range
Buoyant helicopter market
Some replacement models might be similar to X3, says Mr Billig. "We are assessing the performance of X3 and we will apply it to helicopters where it makes sense," he says.
But his boss, Mr Bertling, adds there will still be a buoyant market for conventional helicopters. "For example, one of the great growth areas is servicing wind parks offshore, and here high speed doesn't make sense," he says.
Typically, the faster an aircraft moves horizontally, the less able it is at vertical take-offs and landings, so any aircraft that tries to be both helicopter and plane will be a compromise that is neither fish nor fowl in some situations.
Hence, rather than compete with fixed-wing planes or even with conventional helicopters, which will continue to serve growing markets in Asia, Latin America and the US, as well as here in Europe, the X3 and other helicraft of its ilk are carving out new niches in the aviation market.
Such aircraft could be used on new routes between city centres, such as between London and Brussels, or even within mega-cities, such as Mumbai, where vertical take-off and landing would save time by not having to travel to and from airports.
Other customers, such as the oil and gas industry, could speed up air shuttles to and from the rigs, thus enabling crews and experts to spend more time actually working.
Such customers would be particularly sensitive to the cost of the helicraft, Mr Bertling observes.
Whereas for others, such as search-and-rescue or military customers, it is "less a question of money and more about mission success".
That does not make it a licence to print money, however.
"Operating with high margins in military areas - outside the US, I have to say - is not that easy in the current climate," Mr Bertling observes.
BBC News 15 June 2011
Surging in from the west through one of Provence's many beautiful valleys, a peculiar looking aircraft is preceded by an unfamiliar sound.
The deep chugging rumbling of a conventional helicopter rotor is mixed with the loud whining noise of two wing-mounted forward-facing propellers, making it difficult to guess what is coming.
As the aircraft swoops over Montagne Sainte-Victoire, shaking the windows in holiday cottages and farm houses below, it becomes clear that this flying machine resembles nothing else in the skies.
Eurocopter's X3 rotorcraft - pronounced "X cubed" - is basically a chopper with wings, which will be seen for the first time by the public next week as part of the aerial displays at the Paris air show.
The prototype combines the versatility of a helicopter, by way of vertical take-off and landing, with the higher speed of a plane.
"It's exactly like a helicopter," says flight test engineer Dominique Fournier. "But as soon as you've taken off, it's exactly like a fixed wing aircraft."
Helicraft such as the X3 are set to revolutionise aviation, company executives say
Game changers
The X3 is one of the fastest rotorcrafts in the world, having achieved a cruising speed of 232 knots (430 km/h or 267 mph) during a test flight on 18 May.
Though not quite as fast as US rival Sikorsky's equally futuristic-looking but differently designed X2, which achieved a true air speed of 250 knots last September, the X3 has nevertheless made the prospect of ultra-fast helicopters going on sale within years much more likely.
Consequently, both helicopter companies describe their innovations as "potential game changers".
"The aerospace industry today has a new horizon," according to Sikorsky's president Jeffrey Pino. Eurocopter's chief executive Lutz Bertling says "it will be a totally different way of flying".
Mission capability
For the pilot and for passengers, the difference lies in the "very different sensation from flying this when compared with an ordinary helicopter", according to experimental test pilot Herve Jammayroc. "In the X3 we accelerate and decelerate horizontally."
And although the X3 is perhaps a more complex machine to build, "it is easier to fly than a conventional helicopter", Mr Jammayroc says.
For Eurocopter's customers, it is all about balancing costs with how quickly and how far the aircraft can travel.
Hence, although the X3 is at least 50% faster than conventional helicopters, "the key message is not speed", according to chief executive Mr Bertling.
"The key message is productivity," he says, insisting that the X3's greater size makes it a more versatile rotorcraft than Sikorsky's X2.
"We are not selling helicopters, we are selling mission capability," Mr Bertling says.
"If you can do it with a balloon or a fixed wing or a bicycle, you don't buy an expensive helicopter."
Experimental test pilot Herve Jammayroc says it is easy to fly the X3
Productive aircraft
Eurocopter's aim is to deliver an aircraft that increases cruising speeds by 50%, while limiting any resulting increase in costs to 25%.
"The target is a productive aircraft," Mr Bertling says.
"So 210-220-230 knots for us is quite reasonable. And 270-280 knots may be conceivable, but fuel costs get too high."
With the X3, the required technology is pretty much there, according to Eurocopter's chief technology officer Jean-Michel Billig, who is in charge of research and development.
"Today, we believe it should cost in the region of 20% more than a similar size helicopter in terms of cost of ownership," he says.
Fast helicraft such as the X3 are unlikely to replace conventional helicopters
Replacement programme
The X3 forms part of a broader restructuring of Eurocopter, which includes plans to replace its entire current offering of six different helicopter models.
"We have a road map to renew our current product family over the next 10 years," says Mr Billig.
A helicopter programme costs about 1bn euros ($1.4bn; £876m) per year and typically lasts for about six years, so it is a costly exercise.
The company is also working on more fuel-efficient models, such as helicopters powered by diesel-electric hybrid engines, or unmanned or optionally manned helicopters, even full-sized ones that carry passengers.
Improving safety, both in terms of reliable systems and crew awareness, and to reduce operating and maintenance costs, are also central tasks.
Eurocopter is preparing to replace its entire helicopter model range
Buoyant helicopter market
Some replacement models might be similar to X3, says Mr Billig. "We are assessing the performance of X3 and we will apply it to helicopters where it makes sense," he says.
But his boss, Mr Bertling, adds there will still be a buoyant market for conventional helicopters. "For example, one of the great growth areas is servicing wind parks offshore, and here high speed doesn't make sense," he says.
Typically, the faster an aircraft moves horizontally, the less able it is at vertical take-offs and landings, so any aircraft that tries to be both helicopter and plane will be a compromise that is neither fish nor fowl in some situations.
Hence, rather than compete with fixed-wing planes or even with conventional helicopters, which will continue to serve growing markets in Asia, Latin America and the US, as well as here in Europe, the X3 and other helicraft of its ilk are carving out new niches in the aviation market.
Such aircraft could be used on new routes between city centres, such as between London and Brussels, or even within mega-cities, such as Mumbai, where vertical take-off and landing would save time by not having to travel to and from airports.
Other customers, such as the oil and gas industry, could speed up air shuttles to and from the rigs, thus enabling crews and experts to spend more time actually working.
Such customers would be particularly sensitive to the cost of the helicraft, Mr Bertling observes.
Whereas for others, such as search-and-rescue or military customers, it is "less a question of money and more about mission success".
That does not make it a licence to print money, however.
"Operating with high margins in military areas - outside the US, I have to say - is not that easy in the current climate," Mr Bertling observes.
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I guess it will possibly stall in low speed turns like a Hind as well!
The HIND's wings provide 22% to 28% of its lift in forward flight. In a steep banking turn at slower airspeeds, the low wing can lose lift while it is maintained on the upper wing, resulting in an excessive roll. This is countered by increasing forward airspeed to increase lift on the lower wing. Because of this characteristic, and the aircraft's size and weight, it is not easily maneuverable.
I did see this baby flying overhead at Marignane a couple of weeks ago.
I´m looking very much forward to see a SAR concept of the X3. A +250kts SAR/Medevac helicopter at only 20% more cost than a conventional similar size helicopter is ideal. The placement and use of winch must be something that can be solved and I look forward to see a solution.
I bet it will be loads of fun tackling all kinds of new problems in the simulator like single propeller failures and antitorque failures in hover. I would say the dual prop setup would provide some redundancy and make for interesting problem solving.
I´m looking very much forward to see a SAR concept of the X3. A +250kts SAR/Medevac helicopter at only 20% more cost than a conventional similar size helicopter is ideal. The placement and use of winch must be something that can be solved and I look forward to see a solution.
I bet it will be loads of fun tackling all kinds of new problems in the simulator like single propeller failures and antitorque failures in hover. I would say the dual prop setup would provide some redundancy and make for interesting problem solving.
Last edited by Aesir; 22nd Jun 2011 at 13:01.
Bell 533- over 500km/h
All this top speed talk got me to google the bell compounds in the 1960's as I often drove by the retired airframe at Ft. Eustis, Virginia. A claimed 508km/h (315mph) by the Bell 533! Above 300mph in a highly modified Huey? now that takes some guts!
Bell 533 helicopter - development history, photos, technical data
Bell 533 helicopter - development history, photos, technical data
Happened to be in Marignane yesterday, there was a mini-airshow with EC175 and X3, and EC kindly allowed me an excellent view. 175 - very nice I am sure but just another helicopter. X3, something quite special to see live.
Firstly, the sound is totally different - when it's doing a high speed flypast sounds most like a movie sound effect of a WW2 fighter in a dive, only bit missing is the guns!
Secondly, weird flight characteristics! Its party piece is to hover OGE, then pitch nose UP say 20 deg whilst starting to move forward and up at a steep angle, clawing its way upwards with not much airspeed. In general it looked pretty manoeuvrable and Herve was not timid in demonstrating this!
I was impressed! There was a camera there, perhaps it will end up on YouTube?
HC
Firstly, the sound is totally different - when it's doing a high speed flypast sounds most like a movie sound effect of a WW2 fighter in a dive, only bit missing is the guns!
Secondly, weird flight characteristics! Its party piece is to hover OGE, then pitch nose UP say 20 deg whilst starting to move forward and up at a steep angle, clawing its way upwards with not much airspeed. In general it looked pretty manoeuvrable and Herve was not timid in demonstrating this!
I was impressed! There was a camera there, perhaps it will end up on YouTube?
HC
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There seems to be some news according to this article in AIN online. Apparently EC is doing some final technical adjustments before they plan to increase the speed some more beyond the 232kt reached so far. They want the programme to finish by the end of this year apparently.
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X3 is a pretty sweet-looking design, but given the problems of retreating blade stall, I don't see why any company would stick with a single main rotor design. Call me crazy, but I'm a huge fan of the "Scorpion" design from the movie Avatar. I think with a few slight changes (like the removal of the rotor shrouds), it has the potential to be a great airworthy platform. In brainstorming the design, I came up with a way to increase hover power and thrust for forward (and backward) flight- a swiveling/rotating ducted fan or fenestron on the tail. I'm no physicist so this is probably all just wishful thinking, but I thought it an idea worth bouncing off others with more aerodynamic and mechanical knowledge than myself. Any thoughts? (pics of my design at the bottom of this page: What is the possibility of making this... - Vertical Reference Helicopter Forums)