Eurocopter X3 high speed helicopter

Retrofit said:
How a co-axial rotor (X2) or a tilt-rotor (Bell-Boeing V-22) behave vs a single rotor + tail rotor or, in the X3 case, a single rotor + lateral differiential propellers?

This is pure hypothesizing on my part, but it seems to me the X3 arrangement woiuld be a bit "mushy" in hover. With the props that close to the main rotor hub, they don't have nearly as much of an arm as a normal tail rotor. If they are, say, half as far from the center of rotation as a tail rotor, they produce half a much torque for same thrust level... meaning they have to produce twice as much thrust to counter the same level of torque. Which may well be easy... but fine control would seem to become much more difficult. So a conventional helicopter might remain rock-solid in a hover in breezy conditions, but the X3 would seem more likely to wobble arund a bit.

Of course, it could be that control is good enough so that this difference is hardly noticable.
 
I can think of several angles to look at this:

Wing download:
Anything with a wing will suffer some download in hover, but a militarily-useful X-2 would likely get wings too, so it's probably a wash on that consideration alone.

Rotor design - aerodynamics:
The V-22 has a compromised rotor design in hover because it must also act as a somewhat efficient conventional propeller, so it has excessive (blade twist IIRC), not to mention hopelessly high disc loading. As for the X-2 and X-3, I don't know that single rotors have significantly higher figure of merit than coaxials. Coaxials can take some of the swirl out of the wake, but the lower disc is probably not operating as efficiently as the top one. I'd be willing to say that all other things equal, conventional rotors may hold a small advantage. Coax are found mostly in niche applications such as naval helos for stowage reasons, although it could just be that few companies feel comfortable designing them.

Anti-torque devices:
Tilting the thrust vector as on the V-22 seems to be an efficient way to go about affecting yaw. Regarding the other two helicopters, I guess you need to look at the trade between the moment arm available, power required, and how much weight you pay for it. Weight is not just the powertrain weight, but also the size of the vertical tail surfaces and associated tail structure. From our ongoing discussion, it seems like the X2 might be doing a little better in that regard.

All in all, I think it's safe to say that tiltrotors will have poorer hover characteristics because of their high-speed requirements. For the other two vehicles, it's hard to say. I suspect it's very application dependent. If indeed the X3 is meant as a technology demonstrator for a large cargo helicopter, then Eurocopter's formula may be advantageous. I don't see any armed service seriously considering loading large cargo on a helicopter other than using a rear ramp.On the other hand maybe something small like a scout/attack helicopter would be better matched to the X2 configuration.
 
Re: Tiltrotor Hover Advantages/Disadvantages

Strictly speaking, a tiltrotor has an advantage in hover because of its blade twist. Optimum helicopter rotor blade twist for hover (see Leonardo) is not possible because of the requirement to avoid retreating blade stall in forward flight. Another benefit is that the tiltrotor, like a tandem rotor helicopter, is insensitive to wind direction in a hover. Even better, in transition the tiltrotor is moving sideways, which a tandem rotor helicopter pilot will do if he (or she) needs maximum performance for a confined area departure. From a handling qualities standpoint in the transition from a hover, it is also heading the way the rotors want to go; ask a Chinook pilot what happens when he (or she) loses yaw SCAS in forward flight.

That said, the tiltrotor is not as efficient as a helicopter in hover due to the download on the wing and the higher disc loading preferred for airplane-mode cruise speed. (The disc loading is by no means "hopeless"; the V-22 has a higher disc loading than desired because the range requirement, equipment list, and rotor diameter were independently established.) The tiltrotor's overall superiority or inferiority is therefore mission-dependent as AeroFranz states. An example of an ideal tiltrotor mission is the Tehran hostage rescue. If you are on a Marine assault carrier in the Gulf of Mexico and need to break a friend out of jail in downtown Cheyenne, Wyoming, a properly sized tiltrotor could make a rolling takeoff at dusk with 12 troops on board and fuel bladders in the cabin; land on the outskirts of town before midnight, letting off the assault party (who had prearranged ground transport) and dumping the fuel bladders; rendezvous with the assault party downtown at one or two in the morning, landing in soccer fields and parking lots at 5,000 feet above sea level; bug out with 12 troops and 12 hostages on each aircraft; and be back aboard the ship in the Gulf of Mexico before dawn. No need to buy gas in the U.S.

By contrast, the mission using helicopters takes two nights, not one, as well as buying gas in the U.S. en route to Cheyenne, not to mention on the way back out. In the case of the Tehran hostage raid plan, the helicopters were not coming back. After the assault on the embassy, the helicopters were to ferry the assault team and the hostages to the nearby Tehran airport, which had been seized at the same time as the embassy assault, and everybody was going to transfer to C-141s or something similar. I don't think the concepts represented by either the X-2 or the X-3 have the range at what I'll term their dash speed to accomplish a mission that requires the combination of speed, range, payload, and hover capability that the tiltrotor provides.

From the U.S. Marines standpoint, the V-22 is not a bad helicopter and at the same time, it provides a special mission capability that the helicopter does not. And they are not infrequently called upon to accomplish missions that require that special capability.

Full disclosure: I spent several years promoting the tiltrotor concept with some success due to its superiority at some missions, not my efforts...
 

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Tommy, what exactly was you laughing at so contagiously at the photo? ;)
 
flateric said:
Tommy, what exactly was you laughing at so contagiously at the photo? ;)

I'm pretty sure that the grin never left my face. I had not flown the XV-15 up until then because flight time in it was a scarce commodity and there were very,very few people at Bell who could justify getting a flight before I did. I finally decided that the customer guest pilot program, almost certainly the most effective element of the tiltrotor marketing campaign, had reached a plateau and I could therefore take my turn, one I had looked forward to for a long time.

I was probably one of the more knowledgeable XV-15 guest pilots, having worked on the program since before the NASA proposal was submitted, flown the XV-15 simulations at Bell and NASA, helped edit the flight manual, sat in the cockpit (both mockup and actual) and seen the cockpit flight video many times, watched numerous flight demonstrations, flown chase (as copilot in the Kingair before we got the Citation since we needed a faster airplane) during an XV-15 test flight, and discussed the experience with both the Bell test pilots and many of the 100 or so guest pilots who preceded me. It still knocked my socks off.
 
As already mentioned its all about the mission. For instance while V-22 probably would not be a great canidate for plane guard or ship-to-ship resupply (lots of hover there) it remains a great canidate for COD and VOD, as well as CSAR for the Navy. An assault helicopter actually spends little of its time doing hover work, even when doing external loads one tends to spend as little time as possible hovering, the Tilt rotor is a good canidate because of responsiveness and minimal time in threat envelopes. Now for a scout attack aircraft you do spend a lot of time at very low speed, but do need dash speed as well. This is where an X-2 or X-3 type would likely come out better (not to mention that near ground level whirling propellers and infantry are a catastrophy waiting to happen). Of course the X-2 does not have to have the pusher turning at a hover.

One area I would think X3 might be better than X2 would be in vibration. I have to wonder if the co-axial rotors with opposing lift at different points on the rotor mast must have some challenging frequency issues to be dealt with that the single rotor does not. Of course those turbo-prop out there on the wing tips tide to the transmission might be as bad.
 
Tommy, I saw the XV-15 at the Dayton airshow somewhere between 1989 and 1991 and I have to say, it was one of the most impressive demo's I've ever seen. Not just due to it's capability, but also how damned quiet it was. It just purred.

As for the X-3 and it's anti torque capability, it's obviously capable based on the video, but I can't help thinking it isn't as efficient as it could be due to having to operate within the rotor's flow field. I'm sure these trade offs have been studied well by Eurocopter, I just thought I would point that out. My guess is, the anti-torque capability is more of a byproduct of the cruise thrust requirements, so it's probably just not as fuel efficient in hover as the X-2 or a standard helo, but the penalty is most likely minor.
 
Tommy, is the XV-15 at Udvar Hazy the one you flew? I see that bird just about every week. Sweet looking bird, especially in its livery.
 
AeroFranz said:
Tommy, is the XV-15 at Udvar Hazy the one you flew? I see that bird just about every week. Sweet looking bird, especially in its livery.

I flew 702NA. It later crashed at Bell but neither test pilot was injured. The one at Udvar is 703NA.
 
yasotay said:
As already mentioned its all about the mission. For instance while V-22 probably would not be a great canidate for plane guard or ship-to-ship resupply (lots of hover there) it remains a great canidate for COD and VOD, as well as CSAR for the Navy. An assault helicopter actually spends little of its time doing hover work, even when doing external loads one tends to spend as little time as possible hovering, the Tilt rotor is a good canidate because of responsiveness and minimal time in threat envelopes. Now for a scout attack aircraft you do spend a lot of time at very low speed, but do need dash speed as well. This is where an X-2 or X-3 type would likely come out better (not to mention that near ground level whirling propellers and infantry are a catastrophy waiting to happen). Of course the X-2 does not have to have the pusher turning at a hover.

One area I would think X3 might be better than X2 would be in vibration. I have to wonder if the co-axial rotors with opposing lift at different points on the rotor mast must have some challenging frequency issues to be dealt with that the single rotor does not. Of course those turbo-prop out there on the wing tips tide to the transmission might be as bad.

A factor that weighs in here is that there's only so much deckspace and money. There simply isn't going to be a program to develop a separate vehicle for VERTREP. Whatever is going to be used is going to be a vehicle designed for another mission. Because of its lifting capacity, the V-22 would be a candidate, but as an adjunct to its regular roles. The optimum would be a pure helo since high speed is not necessary, although the V-22 can carry external loads faster than any pure helicopter. Again, the more time in transit, the better the V-22 looks, such as in the COD/VOD missions you mention.

A good example of using existing vehicles is how the H-60 is for now going to do almost everything for the Navy. It's replacing the RH-53 for minesweeping and the CH-46 for VERTREP (although there won't be any VERTREP-dedicated H-60s), although it actually isn't as good in those roles as those aircraft. V-22 would be ideal for COD/VOD, but I'm a little concerned that the Navy is apparently going to spend oodles of money to extend the life of the C-2s.

Tying it back to this topic, I think all of these roles are ones where X3 technology would not be as good as X2 or Tilt-Rotor.
 
FYI, I did my best at a transcript of the X3 video:

0:00, Lutz Bertling, President & CEO of Eurocopter: “For Eurocopter, as the leading helicopter manufacturer in the world, innovation has always been a priority. This is why we have doubled since 2007, our self-funded research and development budgets. And why we have taken the commitment for the first flight of a technology demonstrator, a new version, or a brand new helicopter, every year from now on.”
0:28, Bertling: “Now in economically more difficult times, it’s from our point of view even more important, to invest in your future, and new solutions for you and new solutions for our company and our future as well. And it’s not without reason that I’m standing here in front of an EC155 – a helicopter that you know very well. But based on this, we have developed a new concept, a concept which we call ‘X-cube’ – a concept for more speed, more range at affordable cost.”
1:08, Jean-Michel Billig, Research & Development: “Yes, we believe there is a market for high-speed helicopters for oil and gas [exploration], between shuttle between small cities, for search and rescue missions for the military. But we believe that the high speed cannot be achieved at any cost. So we have been investigating, the high speed solution offering all the functionalities of a helicopter, the hover capability, offering a high speed solution at reduced life cycle costs for the customer.”
1:40, Phillipe Roesch, Innovation: “X3 is a proof-of-concept demonstrator of the H3 concept. H3 stands for High-speed, long range, hybrid helicopter. It’s an advanced VTOL concept, blending the hover capability of the helicopter with the high speed cruise efficiency of the turboprop at an affordable cost. This project was launched in January 2008 to validate the H3 technical concept, aircraft control and trim strategies, anti-torque and yaw control, propulsion, rotor speed governor, and power management system.”
2:31, Billig: “Describing the parameters to design our X3, we’re aiming at preserving the versatility of the helicopter, in hover, in autororation, and also the versatility of the missions of the helicopter.”
2:50, Roesch: “Good performance in hover requires low rotor disc loading, typically a helicopter rotor. The rotor rpm then is reduced at high speed to avoid drag divergence at the tip of the advancing blade. A small wing then partially unloads the rotor at high speed to avoid the retreating blade stall. Auxiliary propulsion is also necessary to avoid degradation of rotor lift-to-drag ratio at high advance ratios. Wing mounted propellers provide the propulsive force in forward flight and the anti-torque in hover.”
3:50: “In order to minimize the X3 development effort – cost and schedule – we have reused a number of components from several Eurocopter helicopters. For example, the airframe has been taken from the Dauphin 365 N3; the main rotor, from the EC 155; the main module of the gearbox – the main gearbox – comes from the EC175. It was adapted with lateral power outputs towards the propeller gearboxes in a specific development. The engines come from the NH90, big engines, probably oversized for this type of aircraft. The trim actuators are coming from several aircraft, I think the EC145, and the serial actuators is a standard piece of equipment on most Eurocopter helicopters.”
5:45, Bertling: “You will actually miss our nice Fenestron on the helicopter which you will see in flight in a few seconds. The X3 technology demonstrator which successfully made its first flight is a totally new concept, which will provide you, our customers, with a cost efficient, best-value-for-money solution for all your missions, in particular, if speed is of essence.”
6:49, Daniel Semioli, Flight Test Engineer: “It’s really something, I should say, amazing. It’s a special day. First of all, because I’m so happy to fly for the first time in this aircraft with Hervé. We flew already in 2000 together on the 725 for the first flight. I should say it was something classical, but today is something exception.”
7:10 Hervé Jammayrac, Flight Test Pilot: “This flight, yes, was very different from a helicopter flight in that it’s a totally new concept, which was easy to fly in hover, and so no big difference with a helicopter. It’s a great achievement for Eurocopter, for all the team that has worked on this project.”
7:28, Daniel Semioli: “And I’m sure that we’re opening a new page of the helicopter story.”
7:35, Lutz: “This new concept, X3 is the best evidence that the innovation part of Shape [Project] – our innovation strategy – becomes reality. We are preparing the future of Eurocopter. And this success is due to strong dedication of teams, hard working teams, with high genius, developing new solutions. We at Eurocopter, we all, we can be proud of our products and our services. But even more, we can be proud of the teams working for Eurocopter. It’s their success, their achievement.”
 
Matej said:
BTW, don't forget that this is only the first first flight this year from the two announced. If the second "first flight" happens, than it will leave us four remaining...

Matej, where have you heard that they have more flights planned for this year and beyond??? Can you point me to any links?

Thanks!
 
Sorry Mike, I don't have any links. What I know I know from the unofficial interview with the Eurocopter representatives during the last Le Bourget and Farnborough. To sum it up, they said to me that they have at least 7 programs of advanced demonstrators, some already in the hardware stage and some in the high level of preparation. For the 2010 two first flights were planned: one was X3 high speed experimental demonstrator and second was X4 - some radical Dauphin high speed modification to stimulate its lowering sales. As for the last five projects, one of them was definitely the Blue Edge and I think that another is ecological diesel-electric helicopter, presented by that weird looking mock-up (I cant remember its name at the moment, but "eco" something).

So till now we saw the X3 demonstrator and I hope that soon also the X4 will be revealed. When they will have the flyable demonstrator, there is no need to hide it, since compared to the pure technological experiment X3, X4 is aimed for the market.
 
Matej said:
For the 2010 two first flights were planned: one was X3 high speed experimental demonstrator and second was X4 - some radical Dauphin high speed modification to stimulate its lowering sales.

Thanks. BTW, you uploaded the jpg from "Flight Int'l" of the attached patent as "X4." Do you think it will look like this? Or will it be new technologies on a conventional (Dauphin-like) configuration?
 

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I dont know. We can only speculate about it now, so lets say, that I hope it can be the design principally similar to that in the patent. It has much sense for the production machine: additional propellers are off the main rotor blast and they are far enough to prevent the collision with the passangers. But another story is the market and the natural conservatism of the customers. As we saw many times in the past (for example Piaggio Avanti), radical designs are not often accepted by the market despite their obvious advantages. So if the X4 is really aimed to increase the Dauphin sales, using that kind of the modification is going to be the risky decision.
 
Eurocopter News
March 2010

X4 Dauphin?
Eurocopter chief executive Lutz Bertling has confirmed at a January 2010 press conference that the company is developing a new Dauphin family size helicopter provisionally known as the “X4”. With requests for French government financial support open, Eurocopter is seeking to create an environmentally friendly design which benef its from the use of green technologies. However, if unsupported, the EADS owned manufacturer from Marignane will fund their own design, presumably using more conventional production methods.
Official launch date for the project is slated for early summer 2010. Rumors are already rife whether the new model will be the AS.365N5 to be known as the EC-165, or as an EC-155 model.
Whether Turbomeca will supply the powerplant or Rolls-Royce will be favored with a RTM322 derivative.

Turbomeca To Power Eurocopter X4

Jul 18, 2010

By Robert Wall wall@aviationweek.com
LONDON

Although a deal is not set, yet, Turbomeca is likely to provide the powerplant for Eurocopter’s dauphine replacement program, the X4.

The move in favor of the French helicopter engine maker is likely given the financial contribution the French government is looking to make into technologies that would be applied to the X4. Eurocopter CEO Lutz Bertling expects around €250-300 million to flow towards the underlying technology, although he is eager to stress the support is not product specific, which would violate European Union state aid rules. The money would support various elements of helicopter technologies, including blades, engines, and avionics.

Details of the X4 are still closely held, but Eurocopter is showing a five-bladed configuration that could feature passive and active blade technologies to reduce the noise signature of the rotorcraft.

Bertling says the goal of X4 is to deliver a step-change in safety and environmental performance.

similar Russian Helicopters concept got EvoGREEN designation
 
Given the X-x has a 'traditional' main rotor plus auxiliaries for propulsion, and has 'much' commonality with production helos, it may attract less suspicion than eg a tilt-rotor...
 
Feast your eyes. Photo taken on November 17, 2010.
 

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Those stub-wings look more like pylons, ie too small to interfere while hovering...

Of course, those props would block pylon hard-points...

Uh, perhaps pushers ??
 
vstol said:
Feast your eyes. Photo taken on November 17, 2010.

That IS a nice shot. I must say, i've always found compounds that use this configuration (Gyrodyne, Rotodyne) rather aesthetically attractive. A purpose-built one, with less helo heritage, might look even better.
 
vstol said:
Feast your eyes. Photo taken on November 17, 2010.

There are three of them in the high-res. The attached one is my favourite http://www.eurocopter.com/site/en/ref/Photos_1100.html#/content/RUB_1100/

Eurocopter’s X3 high-speed hybrid helicopter demonstrator, which performed its maiden flight on September 6, 2010, has reached on November 29th the program’s Step 1 speed objective: attaining a true airspeed of 180 kts (333 km/hr) in level flight at a reduced level of engine power. This performance was obtained at the DGA Flight Test base in Istres, France.

In the flight testing performed thus far, the flight envelope has been opened with and without autopilot to validate the basic hybrid demonstrator aircraft’s stability and handling characteristics. The X3 has reached an altitude of 12,500 feet (3,810 meters) and performed maneuvers with left and right turns at bank angles of up to 60 degrees.

.....

Having already surpassed the speed of a traditional helicopter, the next milestone for the demonstrator is the Step 2 phase at Eurocopter’s headquarters in Marignane, France, where the X3 will enter a second set of flight tests during which it is expected to reach sustained cruise speeds in excess of 220 kts.

.....

http://www.eurocopter.com/site/en/press/_739.html
 

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For 2011, key civil developments will be the launch of the X4, a "game changing" successor to the 365 Dauphin, as well as the first flight of a new version of an existing, but unspecified, model. Eurocopter will also validate the first use of diesel engines in light helicopters, and make further improvements to its so-called "bluecopter" technologies, including the noise- and vibration-lowering Blue Pulse and Blue Edge programme.

http://www.flightglobal.com/articles/2011/01/24/352233/eurocopter-expects-more-lucrative-mix-in-2011.html
 
X3 = making new stuff from the old + cumbersome + complicated layout + ugly
X2 = brand new airframe + sleek + simple coaxial configuration + handsome

If it weren't for politics, the X3 wouldn't stand a chance!

Plus the fact that they couldn't think of anything better than "X2 + 1" as a designator is LAME!!!
 
Stargazer2006 said:
Plus the fact that they couldn't think of anything better than "X2 + 1" as a designator is LAME!!!

As a professional marketing director, I disagree with that ;) But what I really dislike (in the whole major European aerospace industry) is its stupid strategy in this case: "We wont declassify the single photo or the single piece of information of our new helicopter at least until the first 500 customers will buy it." Just compare how many information, photos and CGIs we have about X-2 and its proposed derivates compared to the X-3. For the aviation journalist it means, that he can write 10 pages long article about the X-2 packed with the bunch of illustrations and photos, but only two or at best three pages long article about the X-3, where he can use only 13 available photos. This is the PR?!
 
Not to mention full-scale mock-ups armed to the teeth (as in the S-97)...
 
Matej said:
Stargazer2006 said:
Plus the fact that they couldn't think of anything better than "X2 + 1" as a designator is LAME!!!

As a professional marketing director, I disagree with that ;) But what I really dislike (in the whole major European aerospace industry) is its stupid strategy in this case: "We wont declassify the single photo or the single piece of information of our new helicopter at least until the first 500 customers will buy it." Just compare how many information, photos and CGIs we have about X-2 and its proposed derivates compared to the X-3. For the aviation journalist it means, that he can write 10 pages long article about the X-2 packed with the bunch of illustrations and photos, but only two or at best three pages long article about the X-3, where he can use only 13 available photos. This is the PR?!

And not just European aerospace industry but any other organization too! NASA has millions of photo, videos, interviews, books, reports, whatevery you name, online, free for use!

ESA has all kinds of funny terms of use on their homepage, and if you search for something like IXV (re-entry demonstrator) you get mostly some politicians' faces! Did they really consider that to be the relevant part of the program? Says a lot.

All the pages are really old and it's just really hard to know if these multi-million programs even exist anymore... If there's a vibrant aerospace sector in Europe, it's surely very well hidden!

I guess they might have hundreds of hugely advanced black programs and nobody would know a thing about them, since even if they try to publicize something, it's just so vague.

Even European museums have really restrictive terms - you can't publish photos that you took inside. (Haven't checked the legality of that by the way.)
 
mz said:
ESA has all kinds of funny terms of use on their homepage, and if you search for something like IXV (re-entry demonstrator) you get mostly some politicians' faces! Did they really consider that to be the relevant part of the program? Says a lot.

Indeed. And that is very much a lasting syndrome with the European (and notably French) aviation industry since the 1960s. Lots of focus on people instead of programs. Publications and brochures made here are often packed with portraits of supposedly key people doing a lot of things but not a lot seems to be done...
 
Eurocopter pushes the envelop for single main rotor. Well done!

http://www.eurocopter.com/site/en/press/The-Eurocopter-X3-hybrid-helicopter-exceeds-its-speed-challenge:-232-knots-(430-km-h.)-is-attained-in-level-stabilized-flight_776.html
 
http://www.youtube.com/watch?v=YR9dBCtjhjE
 
Eurocopter to launch third X3 flight test phase Eurocopter will launch a third phase of flight tests with its X3 technology demonstrator within the next few weeks, with the goal of exceeding an original speed target of 240kt (444km/h).
Previous tests have cleared the high-speed aircraft's full flight envelope, and demonstrated a maximum of 232kt. However, this has been achieved by using just 75-80% of its available power, said Jean-Michel Billig, Eurocopter's executive vice-president engineering.
"In the third phase we want to investigate what happens with 100% power to the rotor," he said. The process will last for roughly three to four months.
Billig declined to reveal the company's new target for speed performance, but noted that during the first two test phases "the results were far beyond our expectations".
Meanwhile, Eurocopter is defining potential size requirements and missions for any possible future production aircraft to draw on the X3 programme's work. Candidate roles include search and rescue and offshore operations, plus possible armed applications and VIP transport use, Billig told Shephard's HeliPower conference in Farnborough, the UK on 20 October.

http://www.flightglobal.com/news/articles/eurocopter-to-launch-third-x3-flight-test-phase-363700/

Another pity PR recall - instead of dozens nice new CGI renderings of the possible future production aircraft, we can happily once again use the same photo that we already used x-times since January for our previous articles and blogs. With small hope that finally something will change - shame on you Eurocopter´s PR department!
 
Stargazer2006 said:
X3 = making new stuff from the old + cumbersome + complicated layout + ugly
X2 = brand new airframe + sleek + simple coaxial configuration + handsome

If it weren't for politics, the X3 wouldn't stand a chance!

Plus the fact that they couldn't think of anything better than "X2 + 1" as a designator is LAME!!!

Agreed 100% Those two props fixed to the sides is an idiotic idea. X2 is so much better and it uses a prettier design with its contra-rotating rotors that is both proven and effective.
 
AAAdrone said:
....Those two props fixed to the sides is an idiotic idea. X2 is so much better and it uses a prettier design with its contra-rotating rotors that is both proven and effective.

Please define your criteria for "better", and explain how the X2 is superior to the X3 according to said criteria.

The X3 is mechanically little, if any, more complex than the X2 (think about that co-axial gearbox), and the X3 design (the compound helicopter) is just as "proven and effective" as the X2.

Regards & all,

Thomas L. Nielsen
Luxembourg
 
Lauge said:
Please define your criteria for "better", and explain how the X2 is superior to the X3 according to said criteria.

Where do you put the weapons on an X-3?
 
sferrin said:
Where do you put the weapons on an X-3?

Under the fuselage, on stub pylons a la the OV-10 Bronco, or give the thing slightly more span and hang them off the wings. Besides, both the X2 and the X3 are technology demonstrators, so worrying about where to hang the ordnance would seem a mite premature. And the question would only be relevant for the military market anyways.

Regards & all,

Thomas L. Nielsen
Luxembourg
 
Lauge said:
AAAdrone said:
....Those two props fixed to the sides is an idiotic idea. X2 is so much better and it uses a prettier design with its contra-rotating rotors that is both proven and effective.

Please define your criteria for "better", and explain how the X2 is superior to the X3 according to said criteria.

The X3 is mechanically little, if any, more complex than the X2 (think about that co-axial gearbox), and the X3 design (the compound helicopter) is just as "proven and effective" as the X2.

Regards & all,

Thomas L. Nielsen
Luxembourg

I was using Stargazer 2006's criteria for my marking of the helos. The X2's design just looks better and less like a complete return to the days of the Autogyro.
 
sferrin said:
Where do you put the weapons on an X-3?

And where do you want to put them on the actual X2 airframe? Do you realize how big difference there is between X2 and another future experimental helo S-97 Raider? And remember that we are still not talking about any serial produced operational machine. So why not to expect the same difference between X3 and its possible pre-production successor?

Besides, you probably missed the other very important difference - while X2/S-97 Raider is mostly project for the military use, Eurocopter several times claimed that if X3 be successfull, it will be transformed into the design for civil market to refresh the Dauphin family of helicopters. Military use has now very low priority for Eurocopter.

AAAdrone said:
I was using Stargazer 2006's criteria for my marking of the helos. The X2's design just looks better and less like a complete return to the days of the Autogyro.

So your criteria is "it looks better"? Okay, I accept it as your opinion but its hardly the starting point of rational discussion.

Stargazer2006's arguments were "X3 = making new stuff from the old cumbersome complicated layout ugly". So lets analyze it:

making new stuff from the old - when its related to the technology demonstrator with no chance of serial production (which X2 and X3 for sure are), using existing parts and proved solutions that are not directly related to the main experiment means less cost, less risk and effective. Every manager knows that. And from the conceptual point of view, argument "new stuff from the old" makes me smile when I think about X2 and Sikorsky XH-59.

cumbersome - Really? X3 achieved only a few knots lower speed as X2, but with 75 - 80 % of its available power. One can sit in X3 and directly starts to do an offshore charter of cargo or passangers. Can it be done with X2?

complicated layout - How so? X3 is a Dauphin serial produced helicopter with a new tail, gearbox and two additional wings with propellers. What is complicated on that? And in my opinion there is nothing like "simple" and in the same time "coaxial configuration", especially combined with pusher prop. You can make the tests with coaxial X2 during the nice, shiny weather but try to do it during the storm above ocean - something, that X3 successor is now designed for.

ugly - subjective and for the experimental technology demonstrator it is as important as the color of my grandfather's shoes


I accept every opinion that was written in this topic but try to keep at least some objectivity and usefulness of posts. When someone wants to argue that some airplane/helicopter is bad, because in his opinion it looks ugly, then there are better places for that than Secretprojects.
 
Certainly, I'd look to the predator family in comparison the half-dozen other large UAV projects developed form the 1990s on... the more intermediate iterations the better (and the least ambitious design that can still meet the requirements and still has development potential, the better).

However, one important criticism of the X3 is that downwash shadow cast by the wings will lower stationary lift (and thus maximum VTOL payload compared to a design like the X2).
 
Matej said:
Stargazer2006's arguments were "X3 = making new stuff from the old cumbersome complicated layout ugly". So lets analyze it:

making new stuff from the old - when its related to the technology demonstrator with no chance of serial production (which X2 and X3 for sure are), using existing parts and proved solutions that are not directly related to the main experiment means less cost, less risk and effective. Every manager knows that. And from the conceptual point of view, argument "new stuff from the old" makes me smile when I think about X2 and Sikorsky XH-59.

cumbersome - Really? X3 achieved only a few knots lower speed as X2, but with 75 - 80 % of its available power. One can sit in X3 and directly starts to do an offshore charter of cargo or passangers. Can it be done with X2?

complicated layout - How so? X3 is a Dauphin serial produced helicopter with a new tail, gearbox and two additional wings with propellers. What is complicated on that? And in my opinion there is nothing like "simple" and in the same time "coaxial configuration", especially combined with pusher prop. You can make the tests with coaxial X2 during the nice, shiny weather but try to do it during the storm above ocean - something, that X3 successor is now designed for.

ugly - subjective and for the experimental technology demonstrator it is as important as the color of my grandfather's shoes


I accept every opinion that was written in this topic but try to keep at least some objectivity and usefulness of posts. When someone wants to argue that some airplane/helicopter is bad, because in his opinion it looks ugly, then there are better places for that than Secretprojects.

Thanks Matej for your comments, and sorry if it sounded like I was merely basing my opinion on looks.
The "ugliness" of the design was sort of an additional remark, not the core of my thinking.
I always regret that most aircraft makers nowadays go for proven configurations and so whenever a company truly tries to innovate they naturally have my preference (add to this the fact that Sikorsky has always been a favorite of mine, so I probably was a little biased).
To counterbalance my initial post, let it be said here that I saw the X3 (which is pronounced "X-Cube") flying at the Paris Air Show earlier this year and was truly amazed by its performance. I'm attaching two (not very good) pics taken with my (somewhat limited) Panasonic Lumix camera.
 

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It is a bit unbelievable but marketing finally arrived to Europe. I am really surprised, how nice is Eurocopter presenting its X3 US tour. So after big shame, now comes... good work Eurocopter!

Just one example: http://events.eurocopter.com/en/archive/201206
 

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So I went to lunch earlier today and coming back to the office (situated on the Manassas airport, just outside DC) i see an unfamiliar shape between the hangars, semi-hidden by a fence. My curiosity stirred, i go out on the apron just in time to see an X3 disappearing behind a hangar, ready to takeoff. I thought I had missed it, but to my delight it went up for a short (less than 10 minutes) flight demo. Afterwards it returned to a nearby hangar and i was able to talk to some mechanics and a representative that (of course) lauded the vehicle. They said later this year they will tape it up nicely and decrease drag in order to go for higher speeds.
Sorry for the crappy cell phone picture; SPF member VSTOL happened to be there as well and took much better pictures.
 

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