Airbus Helicopters -plan follow on from X3
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Airbus Helicopters -plan follow on from X3
Airbus Helicopters Reins In Innovation
Is the honeymoon over for Airbus Helicopters and big innovation? Despite the news that the company will build a successor to the X3 compound demonstrator by 2019 (see AIN, August, page 57), Guillaume Faury (who was appointed CEO 16 months ago) seems to have a more cautious approach than his predecessor, Lutz Bertling, and some signs suggest the OEM will scale back its forays into brave new territory.
First, the X4, successor to the EC155/Dauphin, will be equipped with the Helionix suite rather than the radically new man-machine interface originally envisioned for it. “The X4 medium twin, to be unveiled next year at the Heli-Expo show, will share its avionics and autopilot with the EC175 and EC145T2,” Faury said in July. Bertling used to emphasize that flying the X4 would be markedly different from flying any other helicopter, with a lot more assistance for the pilot. In fact, in 2011 he said that someone sitting down in one of the front seats would miss something: the cockpit. The ergonomically innovative cockpit he envisioned, complete with touchscreens, other advanced displays and fly-by-wire controls, would have appeared in a second version of the X4.
The full extent of these plans is history now that Airbus is working on only one version of the X4 rather than the two variants that were to be made available in 2017 and 2020. The second version will simply benefit from regular avionics upgrades to its Helionix avionics suite. As for the fly-by-wire controls, a Sagem spokesman could not confirm whether his company is still developing them.
Faury declined to concede that the revised plans for the X4’s cockpit represent a downscaling of his company’s technology ambitions.
Electric Back-up Motor Project Stalled
But it has shelved another innovative project. The electric backup motor that was tested in 2011 on an AS350 Ecureuil single has not received the go-ahead for development. Faury said Airbus Helicopters has deemed the technology immature and it will not lead to a product in the short term. “We could not find the right tradeoff among weight, price and performance,” he said, primarily, AIN understands, because today’s batteries are too heavy.
As demonstrated three years ago, such a motor would have made autorotation a surer maneuver in the event of engine failure. The motor would not have served as a second engine, but for a few seconds after engine failure it would have maintained a constant rpm and it would have helped during the flare and touchdown. Airbus officials had indicated since 2011 that a launch of the system as a product was imminent.
Research and development spending increased sharply over the last five years. It reached €306 million ($416 million) last year, up from €200 million ($272 million) in 2010 but a modest expansion over 2012’s €297 million ($404 million). Faury took over from Bertling in May last year.
First, the X4, successor to the EC155/Dauphin, will be equipped with the Helionix suite rather than the radically new man-machine interface originally envisioned for it. “The X4 medium twin, to be unveiled next year at the Heli-Expo show, will share its avionics and autopilot with the EC175 and EC145T2,” Faury said in July. Bertling used to emphasize that flying the X4 would be markedly different from flying any other helicopter, with a lot more assistance for the pilot. In fact, in 2011 he said that someone sitting down in one of the front seats would miss something: the cockpit. The ergonomically innovative cockpit he envisioned, complete with touchscreens, other advanced displays and fly-by-wire controls, would have appeared in a second version of the X4.
The full extent of these plans is history now that Airbus is working on only one version of the X4 rather than the two variants that were to be made available in 2017 and 2020. The second version will simply benefit from regular avionics upgrades to its Helionix avionics suite. As for the fly-by-wire controls, a Sagem spokesman could not confirm whether his company is still developing them.
Faury declined to concede that the revised plans for the X4’s cockpit represent a downscaling of his company’s technology ambitions.
Electric Back-up Motor Project Stalled
But it has shelved another innovative project. The electric backup motor that was tested in 2011 on an AS350 Ecureuil single has not received the go-ahead for development. Faury said Airbus Helicopters has deemed the technology immature and it will not lead to a product in the short term. “We could not find the right tradeoff among weight, price and performance,” he said, primarily, AIN understands, because today’s batteries are too heavy.
As demonstrated three years ago, such a motor would have made autorotation a surer maneuver in the event of engine failure. The motor would not have served as a second engine, but for a few seconds after engine failure it would have maintained a constant rpm and it would have helped during the flare and touchdown. Airbus officials had indicated since 2011 that a launch of the system as a product was imminent.
Research and development spending increased sharply over the last five years. It reached €306 million ($416 million) last year, up from €200 million ($272 million) in 2010 but a modest expansion over 2012’s €297 million ($404 million). Faury took over from Bertling in May last year.
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I have read about the X3.
But, I am still puzzled on how it works.
At stationary, would the two propellers be providing thrust at opposite directions, with one towards the rear and the other towards the front so as to provide the counter torque?
As forward flight increases, part of the counter torque may be provided by the rudders, thus allowing the both propellers to provide forward thrust, but still with one stronger than the other.
Does it work that way? Thanking in advance anyone who could shed some light on this.
But, I am still puzzled on how it works.
At stationary, would the two propellers be providing thrust at opposite directions, with one towards the rear and the other towards the front so as to provide the counter torque?
As forward flight increases, part of the counter torque may be provided by the rudders, thus allowing the both propellers to provide forward thrust, but still with one stronger than the other.
Does it work that way? Thanking in advance anyone who could shed some light on this.
I have read about the X3.
But, I am still puzzled on how it works.
At stationary, would the two propellers be providing thrust at opposite directions, with one towards the rear and the other towards the front so as to provide the counter torque?
As forward flight increases, part of the counter torque may be provided by the rudders, thus allowing the both propellers to provide forward thrust, but still with one stronger than the other.
Does it work that way? Thanking in advance anyone who could shed some light on this.
But, I am still puzzled on how it works.
At stationary, would the two propellers be providing thrust at opposite directions, with one towards the rear and the other towards the front so as to provide the counter torque?
As forward flight increases, part of the counter torque may be provided by the rudders, thus allowing the both propellers to provide forward thrust, but still with one stronger than the other.
Does it work that way? Thanking in advance anyone who could shed some light on this.
Eurocopter X3 - Wikipedia, the free encyclopedia
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A rare occasion when Wikipedia is less than reliable (
). According to test pilot Hervé Jammayrac and Av Week's flight test of the aircraft, low speed torque is actually provided by differential pitch:
Vertical's flight test provided additional insight into how the system works in the hover:
The 'successor to the X³' is one of two research projects being part-funded under the EU's Clean Sky 2 Fast Rotorcraft Innovative Aircraft Demonstrator Platform (IADP) effort, the other being AgustaWestland's NextGenCTR (civil tilt rotor):
Shame to hear that the X4’s innovative 'heads up' avionics architecture has been dropped. It'd be interesting to see one of the helicopter OEMs integrate something akin to the F-35’s ‘magic helmet’ HMDS/DAS combination in order to allow pilots to see 'through' their aircraft, e.g. during utility/long-line operations.
I/C
). According to test pilot Hervé Jammayrac and Av Week's flight test of the aircraft, low speed torque is actually provided by differential pitch:
At low speed, rotor anti-torque compensation is provided by differential pitch angle between the left and right propellers, directly controlled by the pilot putting in the appropriate foot pedal movement. At high speed, anti-torque is provided by computer-controlled fin flaps.
The hover attitude was dead level. As [Jammayrac] pulled on the collective, he also set the [thrust control levers] to the hover setting, which provided roughly equal anti-torque thrust from each propeller: forward thrust on the left and reverse thrust on the right. Although, while the propeller’s thrusts were equal, the torques required were not, owing to the different efficiencies inherent in producing forward thrust on the left and reverse thrust on the right. The propeller torque gauges averaged at about 12 percent and 35 percent, respectively.
Shame to hear that the X4’s innovative 'heads up' avionics architecture has been dropped. It'd be interesting to see one of the helicopter OEMs integrate something akin to the F-35’s ‘magic helmet’ HMDS/DAS combination in order to allow pilots to see 'through' their aircraft, e.g. during utility/long-line operations.
I/C
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Thanks for the clarifications.
It seems to me that the X3 configuration is a low risk technological progression from the conventional tail rotor configuration.
It is not worse off in terms of loss of power for counter torque during hover. But it gains significant advantage from the direct horizontal thrust for forward flight.
The only issue is the risk to ground movement due to the propellers. This will likely necessitate doing away with the side doors and rely entirely on the rear ramp, like in Chinook.
This will also mean this configuration may only be suitable for a chopper beyond a certain size.
Do the above observations make sense?
It seems to me that the X3 configuration is a low risk technological progression from the conventional tail rotor configuration.
It is not worse off in terms of loss of power for counter torque during hover. But it gains significant advantage from the direct horizontal thrust for forward flight.
The only issue is the risk to ground movement due to the propellers. This will likely necessitate doing away with the side doors and rely entirely on the rear ramp, like in Chinook.
This will also mean this configuration may only be suitable for a chopper beyond a certain size.
Do the above observations make sense?
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horlick97-
Your comment about the propulsive efficiency of the X3 configuration in forward flight is correct. But your point about potential problems posed by the propellers is not. EC has filed some patents describing a wing/propeller configuration that will resolve the situation. The X3 demonstrator used that particular wing/propeller configuration because it could be readily adapted to the existing EC155 airframe.
Regarding the article John Eacott linked about Airbus Helo supposedly cutting back on "big innovation", I think that notion is wrong. What the company is doing is focusing their development efforts on things that will provide commercial value. The problem with concepts like Sikorsky's X2 or AH's X3 for most commercial applications is whether the higher speed capability justifies the added cost. There are a couple core technologies that need more development before these high-speed compound helos become commercially viable. The rotor blades require better aerodynamics and structures. Reliable high performance blade control systems (like IBC) are needed. Variable speed turboshaft engines are also essential, since they would allow varying the rotor speed without the added weight and complexity of a multi-speed gearbox. It is a better use of resources to develop these things rather than on nonsense like electric hybrid propulsion systems that will provide no value to their commercial products.
Your comment about the propulsive efficiency of the X3 configuration in forward flight is correct. But your point about potential problems posed by the propellers is not. EC has filed some patents describing a wing/propeller configuration that will resolve the situation. The X3 demonstrator used that particular wing/propeller configuration because it could be readily adapted to the existing EC155 airframe.
Regarding the article John Eacott linked about Airbus Helo supposedly cutting back on "big innovation", I think that notion is wrong. What the company is doing is focusing their development efforts on things that will provide commercial value. The problem with concepts like Sikorsky's X2 or AH's X3 for most commercial applications is whether the higher speed capability justifies the added cost. There are a couple core technologies that need more development before these high-speed compound helos become commercially viable. The rotor blades require better aerodynamics and structures. Reliable high performance blade control systems (like IBC) are needed. Variable speed turboshaft engines are also essential, since they would allow varying the rotor speed without the added weight and complexity of a multi-speed gearbox. It is a better use of resources to develop these things rather than on nonsense like electric hybrid propulsion systems that will provide no value to their commercial products.
Most compounds unload the rotor to a degree in high speed flight. In the X3 case I imagine the lift at speed comes from the stub wings and fuselage, and probably less from the articulated rotor in autorotative cruise.
However if the mast could tilt and the rotor was of sufficiently high inertia to reduce Nr and approach efficient Mu values, it could conceivably fly like the cartercopter...though this would likely mandate a main rotor design which, like the CC, is not very efficient in hover.
However if the mast could tilt and the rotor was of sufficiently high inertia to reduce Nr and approach efficient Mu values, it could conceivably fly like the cartercopter...though this would likely mandate a main rotor design which, like the CC, is not very efficient in hover.
Just seen a presentation on CleanSky2 a development of the X3.
Currently the suggestion was that the development was focused for civilian operation, not military with SAR, EMS and VIP transport the suggested mission profile. With the aircraft in the design phase perhaps all may change but with the X3 as a starting point what are the thoughts on anti torque?
The schematic shown for the X3 shows the main gearbox as a EC175 item but with newly designed gearboxes for the wingtip propellers. Does that pose a bigger problem in terms of failure point and consequence? - i.e 2x elements to fail as there are 2x gearboxes for props and also failure of the left gearbox would have great effect on control? Or can one prop effect enough pitch change to control anti-torque? Which if it can why not just run one prop (220knts doesn't seem too challenging from the prop element). How about OEI?
Also with the focus being upon EMS/SAR is prop wash a consideration?
Then operationally with the target being 220knts++ operationally does that present any challenges? Thinking basic collision avoidance to bird strike.
Currently the suggestion was that the development was focused for civilian operation, not military with SAR, EMS and VIP transport the suggested mission profile. With the aircraft in the design phase perhaps all may change but with the X3 as a starting point what are the thoughts on anti torque?
The schematic shown for the X3 shows the main gearbox as a EC175 item but with newly designed gearboxes for the wingtip propellers. Does that pose a bigger problem in terms of failure point and consequence? - i.e 2x elements to fail as there are 2x gearboxes for props and also failure of the left gearbox would have great effect on control? Or can one prop effect enough pitch change to control anti-torque? Which if it can why not just run one prop (220knts doesn't seem too challenging from the prop element). How about OEI?
Also with the focus being upon EMS/SAR is prop wash a consideration?
Then operationally with the target being 220knts++ operationally does that present any challenges? Thinking basic collision avoidance to bird strike.
