Eurocopter X3 hybrid [Archive]

Ian Corrigible

23rd Sep 2010, 23:27

Eurocopter to disclose ‘significant milestone’
AIN (http://www.ainonline.com/news/single-news-page/article/eurocopter-to-disclose-significant-milestone-26455) September 23, 2010

On Monday, Eurocopter is to disclose a “significant milestone in [its] innovation roadmap” during a media event at the helicopter manufacturer’s headquarters in Marignane, France. Industry observers believe the company could finally unveil its plans for a compound helicopter, which is known in the industry as the X3.

In 2008, Eurocopter filed a patent application at the U.S. Patent and Trademark Office for “a rotorcraft [capable of] high speed and…long distances. The document took as an example a 16-seat rotorcraft that could fly more than 400 nm at 220 knots.

Another possibility is that Eurocopter could announce a Dauphin/EC 155 medium-twin helicopter replacement. Dubbed the X4, it was widely expected to be launched by June.

If any new helicopter is announced on Monday, it could very well feature fly-by-wire controls. In 2007, Eurocopter was talkative about developing FBW systems for civil helicopters.

However, more recently the company has become tight lipped and declined to give an update on the technology; a spokesperson told AIN that it is “too secret. Details of Eurocopter’s “significant milestone” will be covered in Tuesday’s issue of AINalerts.
..........
I/C

Frenchrotorhead

27th Sep 2010, 13:29

Here is the photo :
http://www.lefigaro.fr/medias/2010/09/27/75e1ff66-ca32-11df-8901-6fbd366f32cb.jpg

Cheers

Nige321

27th Sep 2010, 16:21

:eek:

http://www.modeltek.com/EurocopterX3-1.jpg
http://www.modeltek.com/EurocopterX3-2.jpg
http://www.modeltek.com/EurocopterX3-3.jpg

Frenchrotorhead

27th Sep 2010, 16:33

Thanks for that ! No more T/R it seems. I wonder if the two antitorque "turboprops" add redundancy. Probably not as good for safety...

misterbonkers

27th Sep 2010, 17:08

would 'pusher' props not have made more sense? - they would have allowed rotors running embark/disembark.

Dave_Jackson

27th Sep 2010, 17:23

misterbonkers,

Two potential advantages of the side mounted pusher-props are;
~ They operate in cleaner air then the pusher prop does,
~ By using differential thrust the propeller under the advancing blades can contribute to forward thrust while still offsetting the some of the torque of the main rotor.

Here is the configuration as experimented with by B.J. Schramm on his Helicycle.

http://www.unicopter.com/Helicycle3.gif

Dave

Bell427

27th Sep 2010, 18:07

iuuu growse:) looks like gang bang incident between EC-155, 175 and C-27J!

Bravo73

27th Sep 2010, 18:50

Woah. That is one fugly critter. :yuk:

skadi

27th Sep 2010, 18:51

And a video:

QECbSxGpXak

skadi

Epiphany

27th Sep 2010, 19:22

A tad premature for the 1st April I think.

Bell427

27th Sep 2010, 19:40

hm...is it just me, or this maschine shakes just a bit too much, acording to video:)

mac oz

27th Sep 2010, 19:54

wow amazing!! i like this speed challenge!
it seems pretty ready for the market :)

sycamore

27th Sep 2010, 19:58

Be very interested to see the low speed/x-wind/sideways/rearwards handling,and whether `changes` get made...

Encyclo

27th Sep 2010, 20:18

I guess you don't have to worry about walking into the T/R :ugh:

You wouldnt make it there alive :rolleyes:

MikeNYC

27th Sep 2010, 20:20

Any coincidence it's called the X3, putting it (in terms of name alone) ahead of Sikorsky's X2? I doubt it. Yeah, pretty fugly... and I don't know if I'd want to board the aircraft with the props turning.

Yellow & Blue Baron

27th Sep 2010, 20:26

This is concept only? Probably any commercial aircraft will have shrouded side rotors or clutch to disengage side engines as these are to dangerous for rotors turning loading/unloading.

Is yaw control by using side engines for left/right movement as you do in a vehicle with tracks?

YBB

widgeon

27th Sep 2010, 21:19

Interesting, how will they lower RPM of the main rotor while increasing power to the tip props?

Bravo73

27th Sep 2010, 22:50

Interesting, how will they lower RPM of the main rotor while increasing power to the tip props?

Variable pitch props?

IFMU

28th Sep 2010, 01:07

Wow, she's a beaut. Nice video too. Not too many points for originality on the name, though.

I've said it before, anybody who makes something new and actually flies it deserves credit. Will be interesting to see how it performs.

Looks like slope landings may not be its specialty, unless you are nose up/nose down the hill.

Is it FBW or mechanical? From the video it sounds like it is not FBW. Would seem to be crying out for a FBW solution, then again maybe blending collective position vs thrust vs speed vs antitorque is not that hard.

-- IFMU

212man

28th Sep 2010, 01:23

I'm sure it would need shrouded props to be viable, and they would have the advatage of reduced diameter too. It will be interesting to hear how fast they get. I know that head/rotor has been to 210 kts on the EC-155 prototype and 240 kts on another demonstrator, so lots of potential!

The name is not X-three, it's X-cubed.

76ranger

28th Sep 2010, 01:38

I liked it better when it was called the Fairey Rotodyne!

IFMU

28th Sep 2010, 01:43

The name is not X-three, it's X-cubed.

Whoops! I stand corrected.

-- IFMU

fling-wing_1

28th Sep 2010, 04:17

Well damn!!!

Back in the secondary/uni days I came up a with a concept for a helicopter/compound aircraft. I couldn't interest any of the engineering profs at my uni so I filed it away.

It was based on a Rutan concept for a two place aircraft in Popular Mechanics. My design was a two to three place aircraft with staggered seating, the third possibly facing backwards, with a forward swept, negative staggered wing, bicycle landing gear with outriggers (a la B-52) and either wing mounted pusher props or ducted fans. I gave up on the idea of a pure heli and settled on a jump take off gyro with a powered rotor to overcome the induced drag of a pure gyro ( see Igor Benson's Powergyro concept) with an unloaded rotor flying on the wiing (Like the Cheyenne.) I figured 180 kts+. Not unreasonable given the technology of the 60-70's.

High speed, long loiter times at altitude would make for a great UAV. Too bad I'm a bit of an anti-statist :uhoh: Well more power to them! Will be cool to see what they come up with...

ShyTorque

28th Sep 2010, 08:03

Looks great. I always thought the Rotodyne concept was way ahead of its time; here it comes again :cool:

However, rotors running crew and pax changes will need some careful thought...

The benefits of a high speed SAR machine was mentioned. Where does the winch fit?

Frenchrotorhead

28th Sep 2010, 13:54

Seems like resonance between the wings/nacelles and the wide tailfins.

Lonewolf_50

28th Sep 2010, 13:58

OK, under those nice fairings are, based on my count of intakes, three engines. Does the transmission allow all three to drive the head, and clutching allow for power transmission to the side mounted assemblies?

Neat looking machine.

Maybe a slight forward sweep on the wings would be a good idea ... though CG issues may arise ...

skadi

28th Sep 2010, 15:14

OK, under those nice fairings are, based on my count of intakes, three engines. Does the transmission allow all three to drive the head, and clutching allow for power transmission to the side mounted assemblies?

There are just two engines installed ( from NH90 ) and the XMS ( EC175 ) has two lateral outputs towards the props.
See the vid i posted above!

skadi

Ian Corrigible

28th Sep 2010, 15:25

Any coincidence it's called the X3
Possibly an attempt at one-upmanship, though it also fits in with EC's nomenclature for its 'one new product every year' plans, the future Dauphin replacement having already been 'announced' as the X4.

This is concept only?
Almost certainly. Given Europe's on-going requirement for a Heavy Lift Helicopter (http://www.pprune.org/military-aircrew/281516-new-european-heavy-lift-helicopter.html), it's interesting to remember that Sikorsky's X2HSL (www.pprune.org/rotorheads/191164-super-heavy-lift-coaxial-helicopter.html) and Boeing's most recent ULOR (http://www.secretprojects.co.uk/forum/index.php/topic,6846.0.html) concept both use auxilliary propulsors.

under those nice fairings are, based on my count of intakes, three engines
The vid posted by Skadi confirms two engines (2,100 shp class RTM322s, replacing the AS365's 838 shp Arriel 2Cs); the center intake is cooling air for the gearbox complex.

I/C

Earl of Rochester

28th Sep 2010, 15:42

OK, under those nice fairings are, based on my count of intakes, three engines.

Was also going to say nay to this, more than likely cooling for all that input to the mgb.

Seems like resonance between the wings/nacelles and the wide tailfins.

There was severe resonance in exactly these areas and I dare say that the chaps from EC may even have been a little surprised.

Cattletruck did elude to it in his comment:

I would think the lower moment of the pusher/puller props from the MR head would contribute significant pitching movements (like a boat) as the couples fight each other for equilibrium.

This a/c must surely be a testbed and I am sure that if it goes into production will look nothing like it does now. Someone mentioned shrouded rotors - anyone remember Dowty?

http://www2.nlr.nl/public/facilities/AVET-Info/Content/Pics/Prop_ductedfan.jpg

http://static.rcgroups.com/forums/attachments/5/6/2/6/t343220-0-thumb-BN2-fans2.jpg?d=1116525983
Dowty's Ducted Fan Islander

Not only do the props need to become ducted fans or similar but I am sure the entire wing assembly will be modified to accommodate optimal dynamic relation with the main and side rotors.

If they didn't go for fans then the side rotors should ideally become rearward facing (if the cg can be maintained) to encourage better safety.

Just taking a wild stab at the vibration from the side props .. my guess is that the pylons are too flexible and probably have little by way of damping measures.

It will be interesting to see how x-cubed ends up!

Earl

Lonewolf_50

28th Sep 2010, 19:45

skadi:
I don't typically click on vids. Might take a peak at this one later, though.

Thanks to you and Ian and Earl for insight on third inlet: cooling that transmission sounds a good idea. :ok:

Pandalet

29th Sep 2010, 10:26

New Euro multicopter aims bitchslap at American X2, V-22 ? The Register (http://www.theregister.co.uk/2010/09/29/eurocopter_x3/)

Franco-Germano-Spanish helicopter agglomorocorp Eurocopter has announced its aspirations to leave a glowing handprint upon the bitchcheek of US whirlycraft titan Sikorsky. In an apparent response to the Sikorsky X2 triplex speedchopper project, Eurocopter has now pulled the wraps off its own supercopter design - which it has chosen to dub the "X3".

"Hah, it is not merely ze Americains who can make ze flying eggbeaters"

victor papa

29th Sep 2010, 11:40

I am surprised at the comments regarding the shrouded rotor. I am sure EC will get there especially seeing that they are the masters of the fenestron? EC is one manufacturer to whom shrouded rotors are not a new concept so I bet as was said before that the eventual product will look different with different concepts but it remains impressive the short time from development to actually flying again as per the 175. You will never know what works best until you actually start flying it I guess.

Rengineer

29th Sep 2010, 13:35

It'd be great if people would just get their facts straigt. Obviously the 1936 Flettner 185 was an autogyro (even if the motor could engage the rotor for jump-start). The Fairey Rotodyne was a gyroplane, which is just an autogyro with tip jets. The same was true the (conspicuously named) VFW H3 from 1969. Keeping with the nerd theme, the X3 is more like the Lockheed AH-56 Cheyenne compound helicopter. The clever bit, though, is apparently that they've combined this design with a variable-RPM rotor like the Boeing Hummingbird. That was the key missing ingredient for high speed. Insofar, it's fair to assume that Eurochopper's goal to provide high speed at less cost and complexity than for a tiltrotor, might be quite achievable.
And yes, I expect them to introduce shrouds, and to disengage the props while on ground. And to make the actual product better looking. But those are details. And anyway, I've recently flown on a plane with two open propellers. Guess what - they only started turning after we were all inside!http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/nerd.gif

BTW, one has to hand it to Lewis Page, he's always a good laugh...:D

riff_raff

1st Oct 2010, 04:25

After watching the video, it looks like the X3 aero and structures guys will need to do some more work before it flies again. The oscillations in the tail surfaces and stub wings looked pretty severe while it was just flying in hover. I would suspect the problem will only get worse at speed.

HeliComparator

1st Oct 2010, 08:27

I'm not sure shrouding the props would enable safe rotors running (dis)embarkation - still too easy to contact the blades. But perhaps there will be a clutch or failing that, just no rotors running turnrounds allowed. After all, you don't often get into an airliner whilst the engines are running!

The wobble looks to me more like autopilot-induced - perhaps the loop gains need turning down a bit to cater for structural flexing?

HC

Heliarctic

1st Oct 2010, 17:37

Pretty it isn´t, but i guess as some say here it´s a technology demonstrator.
And yes quite a bit of the shakes happening.
Remember the Piasecki speedhawk demonstrator that came out some years ago as well?
It was a pusher with the Seahawk as a baseframe.
Wonder what happened to that?
Piasecki X-49A Speeedhawk Compound Helicopter: 250-mph Black Hawk? (http://www.defensereview.com/piasecki-x-49a-speeedhawk-compound-helicopter-250-mph-black-hawk/)

IFMU

2nd Oct 2010, 01:58

Would anybody here want their anti-torque to run through clutches? Would you like to be able to de-clutch your tail rotor for ground ops? Not for me, thanks!

HeliComparitor,
I am not sure the oscillations are from the autopilot. The rotor and fuselage look quiet while the tail and wings shake. I would have said they were tuned to the 1P main frequency. Just my guess.

I believe the speedhawk was sold. There was a thread on it.

-- IFMU

moscovite

2nd Oct 2010, 16:41

We also have been working on this for sometimes and predict to take Russia, China and India markets so dont believe that only America and Eurocopter is going for this.

-qsRJ8HdTkk

Shell Management

2nd Oct 2010, 17:10

The F27 had a clutch one one engine to disconnect the prop and allow it to be used in what IIRC was called 'hotel mode' to provide bleed air and power instead of an APU.

EC's and the final Russian concepts are certainly far less hazardous than a tilt rotor and lighter than Sikorsky's designs.

Dave_Jackson

2nd Oct 2010, 18:48

Competition fosters development. Perhaps conceptual engineering will return to the VTOL arena. :D

The challenges of developing an aircraft with high-speed and VTOL capability will be formidable. However, with damn little humility, I would suggest that the participants solve some of the specific and obvious limitations, THEN apply them to a craft.

Dave

ShyTorque

2nd Oct 2010, 20:27

It'd be great if people would just get their facts straigt. Obviously the 1936 Flettner 185 was an autogyro (even if the motor could engage the rotor for jump-start). The Fairey Rotodyne was a gyroplane, which is just an autogyro with tip jets.

At high airspeed the main rotor of the "X cubed" will presumably be reduced, to avoid RBS, as the props begin to pull. Will it go into autorotation, or close to it?

riff_raff

4th Oct 2010, 04:44

IFMU,

"Would anybody here want their anti-torque to run through clutches?"

On most every rotorcraft I can think of, both main and tail rotor drives run through a type of clutch. That clutch is usually a roller or sprag type clutch.

As for friction clutches, the main lift fan on the F-35B (VTOL fixed wing aircraft) is engaged/disengaged/driven through a massive CRC friction clutch pack. The lift fan on this VTOL aircraft is a much more critical application than a rotary wing tail rotor drive.

Of course, having noted the above exceptions, I would agree with you that any friction type clutch device in an aircraft drivetrain presents inherent reliability/fault tolerance issues. And in my opinion, such devices should be avoided, since by nature they cannot be designed with adequate fault tolerance for any aircraft primary drivetrain application.

Regards,
riff_raff

heli1

4th Oct 2010, 08:10

Received the latest HeliData ( HeliTech issue ) this morning.It has quite a good technical description and explanation of the X3 cubed ,confirming that the main rotor does slow down in high speed flight .The demonstrator has a simplex autopilot with manual reversion and mechanical flight controls ,apparently all part of a Eurocopter desire to make the eventual production aircraft commercially affordable.

nimby

4th Oct 2010, 14:57

IMHO we have here two of the bravest/daftest Test Crew doing a proper "best aircraft I've ever flown" interview after.

... After what though. I reckon in the long shots I saw an inch (25mm) amplitude at the prop boss and possibly more than that at the wing tip. The rotor start-up seemed normal until ground resonance, when I notice they cut the video, but in later shots there are several shakes new to the Dauphin.

The Rotodyne had several design advantages over this in terms of driving vibration ... and still cracked all over.

:ooh:

Dave_Jackson

4th Oct 2010, 17:41

Dear Rengineer, it sure would be great if people, as you say, could get their facts straight..

A HELICOPTER with the ability to hover for an extended period of time does not become an “autogyro with ability to jump-start” just because you say so..:ugh:Dear Svenestron, perhaps you were investigating the FL-184, not the FL-185.

"Flettner then turned in 1935, to the design of the two-seat FL-184, which was similar to an autogyro but had part of the power applied to the rotor during normal forward flight."

"Flettner then took the opportunity that year to explore another system in the design designated FL-185, which could be operated as a helicopter or autogyro by clutching or un-clutching the rotor to the engine gearbox. Cowled and with a frontal cooling fan, a Siemens-Halske Sh 14A 140 h.p. radial engine was mounted in the nose of the FL-185 with a gearbox behind it. From this gearbox, the drive was taken to the three-bladed wooden rotor and also to two variable-pitch airscrews mounted on outrigger arms extending from the fuselage sides.

These airscrews (designed by Flettner as possibly the first with reverse pitch capability) used the full power of the engine to provide forward thrust when the machine acted as an autogyro. When, however, power was applied to the main rotor for helicopter flight, the pitch of the auxiliary airscrews was altered to give thrust in opposite directions and thereby counteract main rotor torque. The amount of anti-torque thrust was automatically governed by a planetary gear unit according to the torque transmitted to the main rotor. Also, the pilot's rudder pedals could act on the anti-torque airscrews as needed to control turns."

mo8_C5J3F3o

______________________

"This machine was the closest a German design came to the Sikorsky system, but only one example of it (D-EFLT) was built. Furthermore, the FL-184 was abandoned prematurely since, by January 1938, Flettner had decided that this new twin rotor system then being tested promised a better power efficiency by converting total engine power into lifting force as far as possible. At the same time this permitted a more compact arrangement. Flettner's quite different intermeshing contra-rotating synchronized rotor scheme ensured that one rotor inherently balanced the torque of the other."

from Aeroplane Monthly, October 1975

Dave

Dave_Jackson

4th Oct 2010, 21:09

Svenestron,

You are correct. You only discussed the FL-185.

I was wrong in assuming that the discussion was about both craft, after reading "Obviously the 1936 Flettner 185 was an autogyro."

Dave

Edit:
Information on the Flettners;
The FL-184 (autogyro with partially powered rotor) flew in November and December of 1936. The FL-185 (helicopter, which was the intended successor to the FL-184) first flew in the summer of 1937.

Information relevant to the Eurocopter X3;
"Hovering proved quite easy. Whilst the FL-185 V1 behaved beautifully at speeds under 65 km/h (40 mph), speeds in excess of this were not possible as the rearward thrusting airscrew would begin to vibrate badly."

Senior Pilot

4th Oct 2010, 21:41

Dave_Jackson & Svenestron,

The thread is about the Eurocopter X3: let's try to keep it on topic :ok:

IFMU

5th Oct 2010, 01:43

IFMU,
On most every rotorcraft I can think of, both main and tail rotor drives run through a type of clutch. That clutch is usually a roller or sprag type clutch.

As for friction clutches, the main lift fan on the F-35B (VTOL fixed wing aircraft) is engaged/disengaged/driven through a massive CRC friction clutch pack. The lift fan on this VTOL aircraft is a much more critical application than a rotary wing tail rotor drive.

Regards,
riff_raff

riff_raff,

Agreed that all helicopters that I have flown (only about 4 types) or I am familiar with (a few more) have an overrunning clutch between the engine(s) and the rest of the drivetrain. This serves to disconnect the engine should it fail, allowing the pilot to autorotate. They work great. When the engine fails, the torque goes away, yet the tail rotor still spins, allowing full yaw control. This is a lot different than a clutch between the main rotor and the source of anti-torque, as proposed in the X^3. If that clutch fails, you can still have torque on the main rotor, but you have no anti-torque. This is generally bad.

The F-35B is really cool. It also has ejection seats, so if the clutch fails in hover you have another option. To me that makes the clutch a lot less critical.

The failure modes of a clutch located between the main and tail rotor of the X^3 would be bad, as they would be bad on a more conventional helicopter as well.

-- IFMU

HeliComparator

5th Oct 2010, 10:46

IFMU yes, on reflection I agree with your point on clutches in anti-torque components! Looks like it will be no RRTR then!

As for the wobble, the fuselage is resonating, but I suppose we can't tell whether the excitation comes from rotor imbalance, pulses of downwash as the rotor blade passes, or flight control input (from the AFCS). I still think its most likely the last one.

HC

Jack Carson

5th Oct 2010, 18:53

The AS-316C Allouette III utilizes a friction clutch that is manually engaged and disengaged by the pilot. I don’t believe that there have been any significant issues with any failures of this system over the years. The duel thrust system on the X3 could actually provide a level of tail rotor redundancy if properly integrated.

riff_raff

9th Oct 2010, 00:28

IFMU,

I watched the X3 video again, but did not see or hear any mention of the prop drives having a decouple/clutching function from the MR drive.

The video has a nice see-through CAD image of the MRGB input bevel gear drives that I captured and enlarged. Couldn't see any clutches in that image either. Just a 2-way power split at the first bevel mesh, with two more bevel meshes changing the shaft angle and providing the necessary offset to pass the driveshaft inside the stub wing box. There is also another bevel gearbox at each prop nacelle, but I don't think there's any clutching device located there.

There was mention of slowing the MR at high forward speeds, but I'd speculate that this is accomplished simply by reducing engine speed. Those RTM322 engines can probably be run at 80% (or less) of rated speed without encountering combustion stability issues.

riff_raff

IFMU

9th Oct 2010, 01:08

riff_raff,

I either read in an article somewhere, or read it on pprune, that clutched props were the answer to passenger entry & exit. I would have said I heard it on the video, but I think you are saying it is not there. I would agree there are no clutches on their demonstrator. Makes sense to keep the demonstrator simple and work out the details later.

-- IFMU

Ian Corrigible

10th Oct 2010, 22:42

Svenestron,

To your second point, EC might have been better to follow SAC's lead and only publish still photos (as was done with the X2's 'squirrely' first flight), saving the video for a later flight.

The stated 220 kt speed target is 'interesting' given that a Dauphin with only half the power (and no props) did 200 kts (http://helimat.free.fr/dgv.htm) almost 20 years ago.

I/C

Dan Reno

11th Oct 2010, 23:48

It appears Carter Aviation has the X2 & X3 beat !

Carter Highlight Video on CarterAviationTechnologies.com (http://www.cartercopters.com/highlight_video.html)

Ian Corrigible

9th Dec 2010, 16:34

In-flight footage released today:

cPYKktIdvoM

I/C

Ptkay

10th Dec 2010, 10:25

Eurocopter, an EADS company (http://www.eurocopter.com/site/en/press/_739.html)

Step 1 speed objective of 180 kts is attained ahead of schedule for this innovative rotary-wing aircraft.

sunnywa

10th Dec 2010, 11:11

It will be interesting to see how this goes in the future. Good luck EC and I hope it goes well (now about the level of suppport EC will give it......:cool:)

Senior Pilot, it was very instructive of Svenstron and DJ to discuss this old pre war technology as I learned something from it. Thanks. Amazing what the old guys got up to. Did the pilot 'Put in the gasoline'?

Rengineer

10th Dec 2010, 12:20

When you look at the video at about 0'59", with the aircraft flying towards the right of the picture in sunlight, you still notice the vibration in the tail fins that some people commented about. But it seems less pronounced than in the earlier video. In general, the take-off and flight scenes seem more stable and "controlled" (I'll edit the post if I can think of a better word) than the first flights. That suggests they may have done something about structural damping and about their control laws. What do you think?

TwoStep

11th Dec 2010, 23:39

They hadn't done a complete rotor track and balance before the first flight.

silverline

14th Dec 2010, 17:54

Saw the X3 fly in to Eurocopter this morning from Istres, closely followed by the EC175. I really didn't want to like the X3 having seen the photos and videos and the wobble from the hastily cobbled together wings and fins, however in the flesh and after a couple of decent passes it actually looks quite good! Very strange sound though, like a Tucano being chased by an EC155!!! Good luck to Eurocopter with this one, at least they are still innovating and investing in the future of aviation, even if there are some resurrected ideas here.

Rengineer

4th Apr 2011, 16:49

Question to the experts at large: Wasn't the X3 to recommence flying in "early March 2011" for the next phase? What's happening, have any of you heard?

TwoStep

4th Apr 2011, 20:25

Believe its still in layup, plans to restart flying towards the end of the month or beginning of May. Eurocopter hope to fly the machine at the Paris Air Show but there are a few hurdles to clear first apparently.

Rengineer

16th May 2011, 11:21

Eurochopper X3 reaches 232kt in stable forward flight apparently:

Link to the Eurocopter press release (http://www.eurocopter.com/site/en/press/The-Eurocopter-X3-hybrid-helicopter-exceeds-its-speed-challenge:-232-knots-%28430-km-h.%29-is-attained-in-level-stabilized-flight_776.html#.TdEGgVupTZ8)

That would be barely 10% less than the Sikorsky X2, a nice trick in any case. What do you think?

Phoinix

16th May 2011, 13:05

I'm not sure of EC's goal here, being a concept should give guidelines to future models; but comparing what they were trying to incorporate in previous helicopters (safety, handling, performance) with cube, it just doesn't add up.

Even as a concept, its very unsafe for ground operations. With that, a lot more mechanical parts of the drive train which probably requires expensive maintenance, large lifting surfaces that don't help with hover performance and it's just not practical.

Genius solutions are simple, this is just a 155 taken from behind by a twin prop plank.

Rengineer

16th May 2011, 13:16

Phoinix, why not read the available information before you diss the concept offhand?:ugh:

Of course it's not unsafe for ground ops, no more than a turboprop plane - remember, those come with props? In fact EC are also planning to use clutches for the props (not sure if they're installed on the concept demonstrator), that makes it even safer than a normal chopper with a tail rotor. Their goal is actually stated quite clearly: Make a helicopter that delivers 50% higher mission revenue for 25% higher cost than today's Dauphin or comparable. If that takes props and a gear, so be it. But of course you'll have two or three easier ways to the same target?

Phoinix

16th May 2011, 13:45

I have read the available info, but that's only numbers, not the design itself.

Even though they plan to use clutches... where does this help in commercial helicopter world, other than A to B?

I expected a bit too much from EC but on the other hand, I was surprised by Sikorsky. It's simple and practical. Although it was used before it was modernized and i think it's more the future I imagined.

I guess we will see what the future brings when the time delivers.

henra

16th May 2011, 16:00

I expected a bit too much from EC but on the other hand, I was surprised by Sikorsky. It's simple and practical.

Hmm, Sikorsky's approach is probably mechanically more simple.
However, very much of the speed gain I would attribute to the very narrow and aerodynamic fuselage.
IMHO if you add a reasonable cabin which has any use for commercial utilization, it will get nowhere near 200kts.
Drag will rise dramatically and the air stream to the pusher will get really dirty. Directional stability will suffer as well.

The x^3 I consider also a vicotry of thrust over aerodynamics. However it has at least a useful cabin. In that regard, they are one step ahead of Sikorsky.

Here's really curious about any practical usages for both designs.

nimby

16th May 2011, 16:27

Sikorsky's approach is probably mechanically more simple

... It's not. That's why it hasn't been done before.

Lonewolf_50

16th May 2011, 16:54

The x^3 I consider also a vicotry of thrust over aerodynamics. However it has at least a useful cabin. In that regard, they are one step ahead of Sikorsky.

Here's really curious about any practical usages for both designs.

henra, I see some promo now and again from Sikorsky about the X2 idea aimed at "next generation" manned scout/attack helicopter ... I'd expect internal weapons pylons, like with Comanche, for their performance to remain valid in the speed metrics they'll try to sell the idea with.

I wonder if that mission won't become a UAV heavy mission in the next generation. :uhoh:

Not so sure about larger "transport" X2 ideas, as the cube/square relationships begin to create problems as dimensions increase.

henra

17th May 2011, 10:34

henra, I see some promo now and again from Sikorsky about the X2 idea aimed at "next generation" manned scout/attack helicopter ... I'd expect internal weapons pylons, like with Comanche, for their performance to remain valid in the speed metrics they'll try to sell the idea with.

Which would make sense. It is practically the only useful area of utilization which I see for the design, as a such a heli doesn't need a bulky cabin. (Cobra/Comanche)
And speed is of great value.

But for commercial applications I have some difficulties to figure out a realistic market. That's mostly about cabin space, useful load and low operating costs / efficient, easy maintenance.
Looking at it, I would say it doesn't shine in any one of those criteria (That applies to a certain extent to both designs, albeit a little less for the x^3).

henra

17th May 2011, 10:36

... It's not. That's why it hasn't been done before.

Probably you're right. I thought it might be structurally a little simpler than the x^3 but compared to traditional helis both are probably significantly more complex.

IFMU

18th May 2011, 01:35

... It's not. That's why it hasn't been done before.

It would seem from a simple view that the X^3 has the equivalent increase in complexity of adding another tail rotor, while the X2 has the equivalent increase in complexity of adding another main rotor. Either one is a lot simpler than a tilt rotor.

It will be interesting to see which concept can make it to a production model first. When they both have a production model, the true benefit of one over the other will become clear based upon specifications and service history.

-- IFMU

FlightPathOBN

18th May 2011, 02:13

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...

rotorrookie

18th May 2011, 02:24

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 :)

jeffg

18th May 2011, 14:00

What happens when one of the props quits working and the other doesn't?

Bravo73

18th May 2011, 14:06

Ian Corrigible

18th May 2011, 16:49

What happens when one of the props quits working and the other doesn't?
If the cross-coupled (?) shafts fail, then you presumably feather the offending propulsor and kick-in a bunch of opposite rudder.

how are you going to let passengers go in and out with engine running
I doubt it'll ever transport passengers in operational service - it's a demonstrator, akin to the X2 TD and XV-15. Any production version would presumably utilize shrouded props and/or a different wing location.

I/C

jeffg

18th May 2011, 17:17

If the cross-coupled (?) shafts fail, then you presumably feather the offending propulsor and kick-in a bunch of opposite rudder.

I guess that kind of gets to my point... how do they plan on handling this? Cross coupled drive shafts, declutching the 'good' prop, provide the 'good' prop with a beta range capability, etc? As far as the opposite rudder it doesn't appear that it will be effective enough (as currently designed) except a high speed and would be ineffective at low speed.

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.

birrddog

18th May 2011, 17:49

If the cross-coupled (?) shafts fail, then you presumably feather the offending propulsor and kick-in a bunch of opposite rudder.

Or just slow down and fly it like a regular helicopter loosing the speed benefit... though depending on the nature of the incident getting on the ground fast may not be a bad idea either!!

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?

JimL

18th May 2011, 18:26

What about the provision of anti-torque when differential drive is removed (at low speed)? Does this mean that there has to be a runway option?

Jim

Dave_Jackson

18th May 2011, 20:33

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

Ian Corrigible

16th Jun 2011, 03:11

Helicopters: now with wings... :E

Helicopter with wings promises to change aviation world (http://www.bbc.co.uk/news/business-13768410)
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."

http://news.bbcimg.co.uk/media/images/53432000/jpg/_53432644_dsc_0809.jpg
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."

http://news.bbcimg.co.uk/media/images/53433000/jpg/_53433351_dsc_0768.jpg
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.

http://news.bbcimg.co.uk/media/images/53432000/jpg/_53432865_dsc_0874.jpg
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.

http://news.bbcimg.co.uk/media/images/53432000/jpg/_53432869_dsc_0931.jpg
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.

I/C

gnz

21st Jun 2011, 15:15

X3 Makes its Public Debut (http://events.eurocopter.com/article/x3-makes-its-public-debut)

RVDT

21st Jun 2011, 15:52

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.

Aesir

21st Jun 2011, 20:53

I did see this baby flying overhead at Marignane a couple of weeks ago.

http://i190.photobucket.com/albums/z171/Icepicture/31052011486.jpg

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.

skadi

22nd Jun 2011, 04:26

Nice vid of the X³

k3w-xXzckTU

skadi

Nige321

22nd Jun 2011, 16:30

And this one too...

http://www.youtube.com/watch?v=6X_H7iwktC0

sandiego89

22nd Jun 2011, 16:48

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 (http://www.aviastar.org/helicopters_eng/bell_533.php)

FlightPathOBN

22nd Jun 2011, 21:03

I14weyVGxCI

HeliComparator

14th Jul 2011, 22:50

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

Rengineer

10th Oct 2011, 12:29

There seems to be some news according to this article in AIN online (http://www.ainonline.com/?q=aviation-news/ainalerts/2011-10-04/eurocopter-plans-higher-speeds-x3-compound). 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.

Praetor

10th Oct 2011, 14:45

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 (http://helicopterforum.verticalreference.com/topic/15016-what-is-the-possibility-of-making-this/))

Dave_Jackson

10th Oct 2011, 18:49

For the technically inclined, this Single Rotor - Reverse Velocity Rotorcraft Proposal (http://www.unicopter.com/1281.html) is functionally similar to the X3. It was presented by Sikorsky at an American Helicopter Society forum 10 years ago.

Later, the wings as shown below, were added.

http://www.unicopter.com/1281.gif

Dave

Frenchrotorhead

6th Nov 2011, 16:33

X3 The Encounter - YouTube

hillberg

6th Nov 2011, 22:09

Knee jerk reaction from the sickhorsey X 2- Please step out after landing I need to speak to you. . . . .. BuzzzzZap. . . .. .

riff_raff

30th Jan 2012, 04:04

Apparently, Eurocopter thinks it can take the speed record away from Sikorsky:

Eurocopter eyes speed record as it resumes X3 test flights (http://www.flightglobal.com/news/articles/eurocopter-eyes-speed-record-as-it-resumes-x3-test-flights-367287/)

Eurocopter will resume test flights of its X3 high speed technology demonstrator next month as it advances the concept towards a potential launch.

In previous rounds of testing the airframer took the X3 to 230kt, using only 70% of the aircraft's avialable power. The next flights will take it beyond this level, although Eurocopter declined to be more specific.

Jean-Michel Billig, the company's chief technology officer said the latest flight test campaign, the third for the X3, will attempt to answer questions thrown up by analysis of data from the two previous campaigns. This will include the performance of the main rotorblades at high speed and how the Fadec system operates when moving between the two flight modes.

Taking the X3 to a higher power will also allow Eurocopter to steal the speed record for a rotorcraft held by rival Sikorsky and its X2.

"That would be the cherry on the cake," said Billig."But my aim is not to break the record but to understand the physics involved. We have to mature the technology before we launch the product."

Billig estimates that technology from the X3 could be seen on production helicopters by around 2020.

Although the concept is being tested on the EC155 Dauphin, Billig said it could equally be used on the larger Super Puma or even something bigger still.

dangermouse

30th Jan 2012, 12:09

Westlands do!!!

and have done for over 25 years

(how many times do we hear the same drivel posted?)

hillberg

30th Jan 2012, 18:23

Bell:ok:, Lockheed :D,Westland :}& Sikorsky:rolleyes: in the 60s & 70s did better. the French X3 is 50 years too late :eek:too much monkey motion :=and Too SLOW.:ugh:

Graviman

3rd Feb 2012, 11:58

Must admit to keeping my mouth shut on this one. The wings will unload the rotor to help with retreating blade stall (like AH-56 Cheyenne), but this solution seems to have greater complexity over the clean sheet approach of advancing blade. Interesting to see whether this can out dash X2...

Ian Corrigible

18th Sep 2012, 17:07

At alicopter's request (or not, as the case may be :E)

Eurocopter plans X3-type helicopter during next seven years
Flightglobal (http://www.flightglobal.com/news/articles/ila-eurocopter-plans-x3-type-helicopter-during-next-seven-years-376405/) 12 Sep 2012

Eurocopter plans to build a production hybrid helicopter with side-mounted propellers - the architecture the manufacturer is evaluating with its X3 technology demonstrator - during the next seven years.

Chief executive Lutz Bertling says the technology will be implemented in a new helicopter during the next "six to seven years", with the new type being specified by the end of 2013.

He cautions, however, that the approval process will take more time than on conventional helicopters because of new certification requirements for the hybrid type.

Eurocopter has made a decision on which aircraft the technology will be introduced in, but declines to reveal its choice for the time being. Bertling says the technology is feasible for any helicopter category, from the medium Dauphin upwards to potential very-large helicopters in the future.

He says Eurocopter is studying helicopters which could accommodate 50 passengers, to replace small regional aircraft at slot-congested airports. He expects the higher speed will not only be a "game changer" in existing helicopter categories but will open up new operational markets, of which a regional commuter rotorcraft could be an example.

Oil and gas operations are another likely field for an X3-type medium helicopter. Bertling says an oil price above $80 per barrel triggers more remote oil field exploration. So with the rising oil price, higher speed becomes more important.

But he adds that emergency services and VIP operations could also be operational segments where the architecture would be welcome.

Dario Franchitti seems sold...

DqyejQiRA6w

I/C

Lonewolf_50

18th Sep 2012, 20:53

He appears to be easily impressed, that one.

Dave_Jackson

18th Sep 2012, 21:31

Over the next decade it will be very interesting to watch how the Xcubed and the X2 compete; and what their specific rotor characteristics are.

Pittsextra

11th Jun 2013, 12:10

Bravo73

11th Jun 2013, 12:52

On a happier EC note.

EADS Global Website - Eurocopter?s X3 hybrid helicopter makes aviation history in achieving a speed milestone of 255 knots during level flight (http://www.eads.com/eads/int/en/news/press.20130611_ec_x3.html)

Not surprising if it's got a 'jet' stuck to the top of it:

http://www.eads.com/dms/Press-DB/EADS/Financial_Communication/2013/June/20130611_ec_x3/X3_copyright_Alain_ERNOULT_624905_490_318.jpg

:E

rotorrookie

12th Jun 2013, 01:25

with new MR hub

skadi

12th Jun 2013, 06:50

with new MR hub

The hub is the same as before, just a fairing for better aerodynamics.

skadi

heli1

13th Jun 2013, 18:26

Lets not downplay Eurocopter's achievement with the X3 which is far less complex than the Sikorsky X2 and therefore likely to be more affordable for the civil market.
But at the same time it is neither the" fastest helicopter" ( as it is a compound design) nor even the fastest compound helicopter....the Bell 533 went faster and all the claims so far are unofficial.
To make an official record one of these aircraft has to cover a measured distance in level flight witnessed by FAI representatives . So far there is no evidence that either the X3 or the X2 can sustain the high speeds to qualify ( The Bell 533 didn't either). Even if they do,they would have to be entered in the compound category,as was the Fairey Rotodyne which I believe still holds the official closed circuit record at 199mph. The true helicopter category requires the lift and propulsion to come through the rotor system,not aided by propellers or add on jet engines.That is why the Lynx still holds the official helicopter speed record.
P.S. The tilt rotor is yet another category!
Just thought someone should put the record straight.

The Sultan

14th Jun 2013, 00:09

Heli1

Eurocopter's excuse for exiting the FVL program was it would be too expensive to make an X-3 based demonstrator. Perhaps they know it is a one trick pony with no real world applications. However, they realize that highest speed and longest range will rule the future where we will most likely be island hopping. That means a tilt rotor.

The Sultan

heli1

14th Jun 2013, 04:02

Sultan. I think the economics is another debate. Bell's most recent design,the Valor , with horizontal engines is a step towards reducing complexity and acceptability in the civil market but the tilt rotor still seems to be the Concorde as against the more utility X3. I guess it will be horses for courses as the tilt rotor will have undoubted speed and range advantages where those are needed but at a cost.
Interesting to compare with what Westland did with the Berp blade that made the Lynx speed record possible.
Instead of developing it to routinely go faster they used the technology more to increase lift and payload,hence on the AW101 they achieved the required performance with five blades,rather than the six that would otherwise have been required without Berp technology.

riff_raff

14th Jun 2013, 05:22

I admire what both Sikorsky and EC have done with their respective compound demonstrators. I especially like that the efforts were privately funded. Both efforts had modest budgets and short schedules (at least by current standards), yet they both performed extremely well in testing.

EC withdrew their proposal for the JMR phase I contract. But that does not necessarily mean they've abandoned efforts aimed at FVL. EC has adequate financial resources to develop a JMR-type flight demonstrator on their own, and doing so would allow them to work in private.

skadi

18th Jun 2013, 18:13

Eurocopter Video: 255kt

JnsI8R6RWaM

skadi

Dave_Jackson

19th Jun 2013, 03:29

http://www.unicopter.com/Flettner_185_Small.gif

If Flettner could only have seen what became of his Fl 185 seventy seven years later.

keesje

20th Jun 2013, 09:34

Flettner

Yes it the bad guys were a big step ahead aerospace innovation. Always (still) an issue in public communication.

On the X3 I saw it at the Paris Airshow this week. The program is winding down. Only 10 flight hours left. Eurocopter kept un usually secret on the X3 project before roll out. Apparently they modified the main rotor for better aerodynamics recently.

http://www.aviationtoday.com/Assets/Image/rotor%20and%20wing%20library/Eurocopter_X3_front_Paris_Air_Show.jpg

It's not like Eurocopter is now sitting on their hands as the article suggests. Contrary. Again in unusual secrecy Eurocopter is working on no less then 4 new generation platforms and they are not far away. Also a medium helicopter for which the X3 seems to have been the technology development platform..

X4 - 4-5t helicopter, first flight 2015
X6 - 11 t helicopter, first flight 2017
X9 - light twin, first flight 2019
X? - medium helicopter using X3 technology (militairy?) first flight 2017-2020

All will be significantly quieter, faster and fully fly by wire.

Tickle

21st Jun 2013, 03:42

Every time I see the X3 I think about all those big moving parts so close together.

I imagine they would have looked at ducted fans or small turbofans like in small business jets. I know they've all been done before on experimental aircraft.

Do you think ducted fans would have useful to focus the thrust and increase safety, if they weren't in the way of the main rotor's effect? Would they generate a coanda effect also?

(I am not too knowledgeable on this stuff.)

Dave_Jackson

21st Jun 2013, 04:24

Tickle,

This shows performance range of different propulsors. It appears that free props are the most efficient.

Dave

http://www.unicopter.com/Propulsion_Efficiency.jpg

riff_raff

22nd Jun 2013, 00:41

Tickle- Here's a 2010 US patent application from EC (https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US20100065677.pdf) that shows one approach they considered for the pusher prop location on their X3.

Tickle

24th Jun 2013, 06:58

Thanks, Dave. I am sure I've seen you post that before. A very interesting comparison. I can see that ducts are definitely out then.

And thanks, Riff. That early design looks like something out of the old US military test machines, like a Cheyenne.

chopper2004

6th Sep 2020, 11:48

On this day ten years ago the X3 flew for the first time ...I was lucky to see it fly to the theme tune of Airwolf a year later at Le Bourget. Then saw it again at Le Bourget in 2013 before being retired to the Museum there so (my photos below again).

cheers

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/2000x1504/481bca33_dc23_44e2_8bbf_6bd2ed90440e_7c33e953c447282943c7982 606117f16024dff40.jpeg
https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/2000x1504/eaceb044_13ad_407c_8190_8ad8b0c69223_60e4063ce9c4864f9e0490b 4c7120bf2e234b0e8.jpeg
https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/2000x1504/13a60c87_2550_407f_83c0_ba6950082077_4161085203baad1aadaa2b0 42a0e4818a4359004.jpeg
https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/5bfb1987_8219_420c_ad19_176a9997b570_b06084c79420be3dfc9120f 7f4776f5f7492134a.jpeg
https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/550199ac_8b71_4356_a121_259465da0910_ac15a26b399bdce3d0ea365 002921a779450d78e.jpeg
https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/ab6d6d15_cffa_45e6_bbd2_4c0046048fe4_737bd954deaa3d19a92123e 37d97f2f5d2672a87.jpeg
https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/73b2dad1_8a96_459c_8932_cf7ace213b5d_e4b99d7e45723545bdac98c ed470e762213d8eef.jpeg
https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/8ca3ac34_026d_4d49_bacb_4fca74a5775c_2c05c45cbe75220095b2a19 d71db92cd9180c225.jpeg
https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/81066321_b2c2_4532_9fd8_92a5fa817c80_8fff897d1021ec039c0d7c4 ed6c1b2be068fbabf.jpeg
https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/14667eb3_e081_4d45_b0f1_63a01ed4955f_685ad1e6ce0835a5b3567fc f41b9174b88964b34.jpeg

Agile

7th Sep 2020, 04:06

looking back, quite a bit of modification on the EC365 airframe (or EC155 airframe)

chopped out the fenestron
Made the rotor mast much longer
flying saucer rotor head

must have been a fun project to work on back then

chopper2004

7th Jun 2023, 21:08

a decade has passed

https://www.youtube.com/watch?v=wK7rJA1FSnY&t=5s

cheers

helispotter

8th Jun 2023, 00:20

a decade has passed...

cheers

It is a great compilation of video footage of the X3.

A few weeks ago, I had been reading about X3 on Wikipedia ( https://en.wikipedia.org/wiki/Eurocopter_X%C2%B3 ) prompted by another PPRuNe thread and they write: "...the X³ achieved 255 knots (472 km/h; 293 mph) in level flight on 7 June 2013, setting an unofficial helicopter speed record (https://en.wikipedia.org/wiki/Helicopter_speed_record)...". If indeed that speed remains unofficial, I have to ask why wouldn't Eurocopter (as it was still called at the time) have made an effort to have that speed ratified by the FAI (https://www.fai.org/records)?

As for FAI speed records for rotorcraft, I am not sure I have worked out how to use their website properly. When searching for "rotorcraft" speed records (limiting search to over 3km course or over a closed circuit), the highest speeds I could find were:

Closed course: 345.74 km/h (186.68 knots) - Thomas F. Doyle jr, USA - set in USA on 8 Feb 1982 in a Sikorsky S-76A
3km course: 372 km/h (200.86 knots) - Guy Dabadie - set in France on 19 Nov 1991 in an Aérospatiale AS 365 N

Perhaps compound helicopters are not categorised as "rotorcraft" by FAI ?

Update:

I should have looked at the link provided in the Wikipedia X3 article: https://en.wikipedia.org/wiki/Flight_airspeed_record#Other_air_speed_records

It lists various additional speed records for what I consider to be rotorcraft, but many of those must be unofficial or at least not recognised by FAI: Westland Lynx, Eurocopter X3, Sikorsky X2, Bell-Boeing V-22, Bell 533.

dangermouse

8th Jun 2023, 06:58

For a helicopter (which X3 wasn't), and we all know what that is....

400 kmh in a Lynx in level flight in August 1986...all the other claims are PR spin from Sikorsky or Airbus for compound aircraft.

DM

Commando Cody

8th Jun 2023, 07:32

It is a great compilation of video footage of the X3.

A few weeks ago, I had been reading about X3 on Wikipedia ( https://en.wikipedia.org/wiki/Eurocopter_X%C2%B3 ) prompted by another PPRuNe thread and they write: "...the X³ achieved 255 knots (472 km/h; 293 mph) in level flight on 7 June 2013, setting an unofficial helicopter speed record (https://en.wikipedia.org/wiki/Helicopter_speed_record)...". If indeed that speed remains unofficial, I have to ask why wouldn't Eurocopter (as it was still called at the time) have made an effort to have that speed ratified by the FAI (https://www.fai.org/records)?

As for FAI speed records for rotorcraft, I am not sure I have worked out how to use their website properly. When searching for "rotorcraft" speed records (limiting search to over 3km course or over a closed circuit), the highest speeds I could find were:

Closed course: 345.74 km/h (186.68 knots) - Thomas F. Doyle jr, USA - set in USA on 8 Feb 1982 in a Sikorsky S-76A
3km course: 372 km/h (200.86 knots) - Guy Dabadie - set in France on 19 Nov 1991 in an Aérospatiale AS 365 N

Perhaps compound helicopters are not categorised as "rotorcraft" by FAI ?

Update:

I should have looked at the link provided in the Wikipedia X3 article: https://en.wikipedia.org/wiki/Flight_airspeed_record#Other_air_speed_records

It lists various additional speed records for what I consider to be rotorcraft, but many of those must be unofficial or at least not recognised by FAI: Westland Lynx, Eurocopter X3, Sikorsky X2, Bell-Boeing V-22, Bell 533.

The FAI defines a helicopter as a craft that derives all lift from rotors and all forward thrust from the same system that powers the rotors. If it has wings or auxiliary thrusters, it doesn't qualify. X3, V-22 and Bell 533 do not qualify. X2, OTOH, does qualify. In fact, after it hit 250 knots, the FAI invited Sikorsky to fly the standard closed course demonstration to take the world helicopter speed record. Sikorsky declined.

As far as the Westland Lynx goes, as Dangermouse said, it has held the FAI world helicopter speed record since 1986. And it didn't even have a pusher prop!

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/400x246/g_lynx_3de0b9bfca290bfb2131c94291730dff19441827.jpg

helispotter

8th Jun 2023, 11:10

The FAI defines a helicopter as a craft that derives all lift from rotors and all forward thrust from the same system that powers the rotors. If it has wings or auxiliary thrusters, it doesn't qualify. X3, V-22 and Bell 533 do not qualify. X2, OTOH, does qualify. In fact, after it hit 250 knots, the FAI invited Sikorsky to fly the standard closed course demonstration to take the world helicopter speed record. Sikorsky declined.

As far as the Westland Lynx goes, as Dangermouse said, it has held the FAI world helicopter speed record since 1986. And it didn't even have a pusher prop!

OK, Dangermouse and Commando Cody, while I would still call X3, V-22 and Bell 533 "rotorcraft" (the term FAI is using) I agree none are pure helicopters. Still, you would hope they then fall into another FAI class of aircraft that is capable of vertical takeoff such that they can also achieve official records in such a class, should the companies have sought an official record.

I have now found the Lynx speed record on FAI website. It is in the record category of "speed over a straight 15/25 km course", that being 400.87 km/h (216.45 knots): https://www.fai.org/record/1843

They also have an article about this record where they describe it as the "FAI Absolute Record for Speed for helicopters over a straight 15 and 25 km course": https://www.fai.org/news/11-august-1986-fai-world-record-john-trevor-egginton

But hopefully someone can now explain to me why achieving that record didn't automatically also qualify it for the "Speed over a 3 km course" record for which the fastest "rotorcraft" is listed as the AS 365 N mentioned in my earlier post at 'a mere' 372 km/h (200.86 knots). It isn't possible to average 400.87 km/h over 15+ km straight course without at the same time averaging this (or higher) for at least one 3km segment of that run. It isn't obvious the "Speed over a 3km course" needs to be in a closed circuit as some other FAI records clearly are.

Update: The FAI has an item on the AS 365 N (AS 365 X) speed record here: https://www.fai.org/news/still-unbeaten-after-30-years-dabadie-speed-record

It mentions: “The speed record over 3km requires the validation on four return journeys at an altitude of 300 feet or under throughout the journey and axis held at +/- 0.1N". So that would explain why the Lynx didn't automatically also gain this record. With return journeys, it isn't possible to take advantage of a tail wind. In any case the article implies this record needs to be conducted in winds below 5 knots. I am not sure what the "+/- 0.1N" is about though?

Lonewolf_50

8th Jun 2023, 15:53

First production unit of the X3 is expected ... when?
I may have mentioned this before, but where the propellers are and where the passenger doors are strike me as ground accidents waiting to happen.

skadi

8th Jun 2023, 16:03

First production unit of the X3 is expected ... when?
I may have mentioned this before, but where the propellers are and where the passenger doors are strike me as ground accidents waiting to happen.

X3 was just a demonstrator, next is the "Racer".

Airbus Racer (https://www.airbus.com/en/innovation/disruptive-concepts/disruptive-design/racer)

skadi

Lonewolf_50

8th Jun 2023, 16:30

X3 was just a demonstrator, next is the "Racer".

Airbus Racer (https://www.airbus.com/en/innovation/disruptive-concepts/disruptive-design/racer)
Thanks for that. I like how the pusher props remove my ground safety concern somewhat.
I am guessing that yaw control in a hover will be differential thrust from the two pusher props.
Assuming FBW?
I expect that they'll have some fun tuning out the vibrations from the engine mounti / wing structures. All in a day's work, I suppose.
Any idea on first delivery?

skadi

8th Jun 2023, 16:58

Any idea on first delivery?

Its also just a demonstrator. First flight later this year.

skadi

Commando Cody

8th Jun 2023, 20:04

OK, Dangermouse and Commando Cody, while I would still call X3, V-22 and Bell 533 "rotorcraft" (the term FAI is using) I agree none are pure helicopters. Still, you would hope they then fall into another FAI class of aircraft that is capable of vertical takeoff such that they can also achieve official records in such a class, should the companies have sought an official record.

I have now found the Lynx speed record on FAI website. It is in the record category of "speed over a straight 15/25 km course", that being 400.87 km/h (216.45 knots): https://www.fai.org/record/1843

They also have an article about this record where they describe it as the "FAI Absolute Record for Speed for helicopters over a straight 15 and 25 km course": https://www.fai.org/news/11-august-1986-fai-world-record-john-trevor-egginton

But hopefully someone can now explain to me why achieving that record didn't automatically also qualify it for the "Speed over a 3 km course" record for which the fastest "rotorcraft" is listed as the AS 365 N mentioned in my earlier post at 'a mere' 372 km/h (200.86 knots). It isn't possible to average 400.87 km/h over 15+ km straight course without at the same time averaging this (or higher) for at least one 3km segment of that run. It isn't obvious the "Speed over a 3km course" needs to be in a closed circuit as some other FAI records clearly are.

Update: The FAI has an item on the AS 365 N (AS 365 X) speed record here: https://www.fai.org/news/still-unbeaten-after-30-years-dabadie-speed-record

It mentions: “The speed record over 3km requires the validation on four return journeys at an altitude of 300 feet or under throughout the journey and axis held at +/- 0.1N". So that would explain why the Lynx didn't automatically also gain this record. With return journeys, it isn't possible to take advantage of a tail wind. In any case the article implies this record needs to be conducted in winds below 5 knots. I am not sure what the "+/- 0.1N" is about though?

The key is that helicopters are a subset of rotorcraft. If they allowed a wing,said airfoil could be used to offload some of the lift from the rotors, thereby allowing the rotor to be slowed allowing for somewhat higher speed but t that point you're no longer fully rotorborne and that gives an artificial advantage over a pure helicopter. Similarly, if they allowed auxiliary propulsion you could hang just about anything on the side and with enough thrust blast your way to victory. Doing that, though, proves nothing. You could do it to any vehicle.

That's why they don't treat Til-Rotors as helicopters, but if Sikorsky would cooperate, any of their X2s could theoretically take the record, unless there's some other issue with the technology that keeps them from trying for it.

megan

9th Jun 2023, 04:41

If they allowed a wing,said airfoil could be used to offload some of the lift from the rotors, thereby allowing the rotor to be slowed allowing for somewhat higher speed but t that point you're no longer fully rotorborne and that gives an artificial advantage over a pure helicopterSo I guess the Cobra is not a pure helicopter as it has a wing ;) Wonder what lift it does contribute.

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/1024x676/bell_ah_1g_815105_157216_hma_773_atl_nas_20_07_76_edited_2_2 894aadf340cdd4d0b979202cac4bd33f6837a47.jpg

Commando Cody

9th Jun 2023, 07:43

So I guess the Cobra is not a pure helicopter as it has a wing ;) Wonder what lift it does contribute.

Remember we're talking the FAI's definition for the purposes of being eligible for the official speed record. As far as the wing on the Cobra goes, its primary purpose is to have some place to hang the weapons, not to offload the rotor to allow it to be slowed (the technology didn't even exist then) for higher speed. It does provide some lift that helps in toting the weapons in forward flight, but its main purpose is to provide weapons stations. Now the purpose of the wing on Invictus is to offload the rotor to allow it to be slowed for higher speeds. If the wing is detached, even though the drag is less, top speed is reduced. There is provision for one weapon station under each wing, but that's just a convenience. The 360 meets Army's requirement with internal stowage and carrying extra weapons under the wing means that weight has to be reduced somewhere else (probably fuel load) and drag goes up limiting top speed.

helispotter

10th Jun 2023, 12:25

As I was curious to see where compound rotorcraft, tiltrotors, etc fit into the FAI records, I searched for the relevant "rules" for rotorcraft. They can be found here:

https://www.fai.org/sites/default/files/documents/sc9_2019_amended_2020.pdf

Sub-Class E-1 relates to "Helicopters" where mostly vertically oriented rotors substantially provide both lift and thrust (per comments by Commando Cody in post #131). But there are also sub classes E-2 (Tiltrotor), E-3 (Autogyro), M-1 (Compound), M-2 (Tiltwing / Tilt Engine). I couldn't find any M-1 or M-2 option in the pull-down menu for FAI records, so perhaps none have been (officially) set in those Sub-Classes to date? But there were a pair of old "E-2" speed records:

356.3 km/h (192.38 knots) speed over a straight 15-25km course set on 7 Oct 1961 in a Kamov Ka-22 Vintokryl.
307.22 km/h (165.88 knots) speed over a 100km closed circuit course with no payload set on 5 Jan 1959 in the Fairey XE 521 (Rotodyne).

I am not sure why either of these are classed as "Tiltrotors", but perhaps when these records were set, E-2 was defined quite differently in the code?

The code also defines how the speed records must be set. The record for speed over a 3km straight course must be achieved at a height (above ground) no greater than 150m and requires two pairs of flights in opposing directions with the speeds then averaged between the four runs. The speed over a 15/25 km straight course requires a pair of flights in opposite directions over a distance between 15 to 25 km. In this case altitude is unlimited but shouldn't be below 150m.