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AIRBUS RACER / Clean Sky2 LifeRCraft Demonstrator

VTOLicious

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TomcatViP

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Re: Clean Sky2 LifeRCraft Demonstrator

This is not R&D. This is biased subsidies. I wonder if any OEM aside of Airbus have had a chance to submit anything different.
 

VTOLicious

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Re: Clean Sky2 LifeRCraft Demonstrator

TomcatViP said:
This is not R&D. This is biased subsidies. I wonder if any OEM aside of Airbus have had a chance to submit anything different.
If you are interested you can make yourself smart at the Clean Sky Homepage:
http://www.cleansky.eu/discover

BR Michael
 

muttbutt

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Re: Clean Sky2 LifeRCraft Demonstrator

TomcatViP said:
This is not R&D. This is biased subsidies. I wonder if any OEM aside of Airbus have had a chance to submit anything different.
Cleansky is open to anyone.....like all Horizon projects you submit your application.
 

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galgot

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Ahhh... finally someone thought "these props in front of the side doors are not a good idea" ;D
 

Moose

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The box wing is an interesting choice. Looking for more lift?
 

AeroFranz

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Stiffer structures, or just as likely looks. We won't know until they show the real thing.
 

VTOLicious

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Moose said:
The box wing is an interesting choice. Looking for more lift?
AeroFranz said:
Stiffer structures, or just as likely looks. We won't know until they show the real thing.
You guys should take the time to read the article! ;)

Tomasz Krysinski, Airbus Helicopters head of research and technology, says the configuration revealed today was "already frozen [at ILA]", having successfully passed a series of windtunnel tests in Germany and the UK in early 2016.

He says that the box-wing design with pusher propellers – which received a US patent last year following a 2013 application – offers performance and safety improvements.

More lift is generated by the box-wing than the wing-stubs Airbus Helicopters used on its X3 demonstrator programme, vital when the speed of the main rotor is reduced in forward flight.

In addition, the up-and-over configuration allows the wing surface to be doubled without a related increase in the area exposed to the rotor downwash, preserving low-speed hover performance.

The box-wing is also positioned on the aft fuselage, moving the rear-facing propellers further back and providing passengers with safe and unobstructed access to the cabin.

And, says Krysinski, the box-wing and pusher prop combination reduces power demand by 10% in forward flight because of the way the air flow is channelled, improving fuel consumption and increasing range.

Main landing gears retract into the lower wing, rather than the fuselage, improving stability on the ground by providing a wider footprint, as well as enhancing the operation of the gear itself.
 

yasotay

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A very smart application for civil operations. I remain unconvinced that it has a good military application, although naval forces have much better understanding of working in proximity to air vehicles that want to kill you.
 

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yasotay said:
A very smart application for civil operations. I remain unconvinced that it has a good military application, although naval forces have much better understanding of working in proximity to air vehicles that want to kill you.
I attended the rpess brief ;last Tuesday and we went to Clean SKies booth to see it being unveiled my photos here

and heres Airbus Helicotpers official video

https://www.youtube.com/watch?v=aV52HAdYIgM

cheers
 

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RavenOne said:
I attended the rpess brief ;last Tuesday and we went to Clean SKies booth to see it being unveiled my photos here
Did they mention any commonality with the H160? It looks to be about the same general size and shape as the H160, but I wonder how much commonality could be left once they're done changing the engines, tail, landing gear, door arrangement etc.

If there is to be little-to-no commonality, then it seems strange to launch a brand new product that would cannibalize H160 sales, versus targeting another segment... So maybe Racer is actually smaller than H160? Could it be the rumored H150 to compete head-on with the AW169 in the 8 pax (4.5-5 ton) segment? (As well as the AW609 obviously)
 

RavenOne

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I think off hand there was mention of some some commonality with H160 but that's the Helionix avionics systems and environmental friendliness (which is how the H160 was unveiled back at heli expo 2015 in Orlando)

Cheers
 

lastdingo

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All that extra effort with pusher props doesn't gain much cruise speed over a helicopter that has large stub wings and 4-5 rotor blades with angles tips.
There's only about 40% top speed gain, at the expense of
  • greater weight
    much greater fuel consumption (litres per km)
    greater maintenance requirements
    less payload
    greater purchase costs

I suppose stub wings with integral fuel tanks should be the way to go if you want speed and range, but they're never used in civilian helicopters (except as volume for retractable landing gears) because of the loss of payload, which is much smaller than with a stub wings + pusher prop design.
 

yasotay

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Brilliant photographs! Thank you for sharing.
 

H_K

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lastdingo said:
All that extra effort with pusher props doesn't gain much cruise speed over a helicopter that has large stub wings and 4-5 rotor blades with angles tips.
There's only about 40% top speed gain, at the expense of
  • greater weight
    much greater fuel consumption (litres per km)
    greater maintenance requirements
    less payload
    greater purchase costs
You miss a critical fact, which is that eliminating the need for forward thrust from the main rotor enables a much higher L/D (lift to drag). That is the point of all compound helicopters, whether they are Sikorsky compounds, jet compounds, tip jets, or in this case pusher props.

So in fact fuel consumption should be much improved over wing-only solutions.

I'll give you that the added weight is an open question: you are replacing one tail rotor with two props, so one additional rotor, with some weight penalty. The wing is also penalizing (both extra weight and lift reduction in hover), but that is true of any high speed helicopter.

My guess is the total weight penalty is 300-400kg... (wings: 150kg, extra prop: 50kg, extra drivetrain: 50kg, more powerful engines + gearbox: 100kg). Most of the penalty is inherrent to all high-speed helicopters, only a small part linked to the choice of pusher props. The oversized engines (to ensure high speed cruise at 220+ knots) likely have enough built in margin to offset this.
 

Triton

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Maybe we should extract the Airbus Helicopters Clean Sky 2 concept material from this existing topic:

"European High Speed Rotorcraft"
http://www.secretprojects.co.uk/forum/index.php/topic,21337.0.html
 

Triton

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Meet the Expert: Tomasz Krysinski - Helicopters Head of Research & Innovation

Published on Jun 20, 2017

In this episode of Meet the Expert, Tomasz Krysinski presents the so-called “Racer”, a new high speed demonstrator developed within the Clean Sky 2 programme.

https://youtu.be/nRHANn2SoZA
 

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Hmmm I wonder if shaft driven is more efficient than a generator and electric motors for the props. With electric motors you could stop the props on the ground and in the hover. I guess you could put clutches on the shafts to do the same thing. Ah well...shafts driving props is what eurocopter knows how to do.
 

yasotay

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coanda said:
Hmmm I wonder if shaft driven is more efficient than a generator and electric motors for the props. With electric motors you could stop the props on the ground and in the hover. I guess you could put clutches on the shafts to do the same thing. Ah well...shafts driving props is what eurocopter knows how to do.
Block 2. version Probably thinking about all the extra certifications that might be needed for electric propulsion. Let others work out the processes first.
 

TomcatViP

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You'll notice that the shaft concept has driven all the system design. it's all about having this dual propulsor arrangement. All the airframe is compromised for that single (dual in fact) goal: the side projected tall landing gear, the bi-plan arrangement, vertical clearance of the lower wing under the propulsor nacelles, the canted trapezoidal wings to better the structural integrity* and minimize wash-out drag... it's all about having this twin fixed pushing prop arrangement.

On the fuselage side, it's the same conceptual design philosophy: the never ending nose is there to offer the least drag at horizontal attitude but compromised the functionality and mass distribution (think rotational inertia). etc...

You have here what seems to be a perfect illustration of vertical project management drift: what falls from the top desks is God matter never to be discussed. Alea jacta est could be a good name for that rather elegant bird!



*but what about its effects on the central gear box that have to absorb complex torque components due to the canted arrangement?
 

coanda

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Yasotay, TomcatVIP - good posts.

Yasotay, it seems likely that certification could be a blocker but I doubt it is a huge hurdle. I think part of Tomcat's response is closer to the mark.

The box wing is almost dictated by having to have shafts. If there were no shafts you would not require the upper wing. There really isn't a good structural reason that demands a box wing - you can architect your way to passing a spar through the fuselage. And if you don't need it.....why have it?

I think you'd be surprised at the autonomy given design teams today. I'm in one of the Airbus units and we have very little dictated to us from on high. In fact we're pushed to innovate wherever we can - especially in the team I am a part of. No this shaft design smacks of being 'safe' from the perspective of the team/company background. For example...why not use electric motors for tail rotors? I can think of structural and mechanical benefits there.
 

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The joined wing probably allows a stiff structure without putting a lot of flat plate in the rotor downwash. It also looks cool...

As for electric cruise motors, by the time you've added generators and motors worth hundreds of kWs, the wiring, and speed controllers, you've got something much heavier than the equivalent mechanical transmission and with lower propulsive efficiency.

to put things in perspective, a mechanical transmission might be 98% efficient, with losses only in the gears.
The motors, generators, and controllers may each be about 95% efficient, throw in one percent loss in the wires, and you're below 80%.

The one place where it might pay off is the tail rotor. You get rid of the long transmission, and you can shut it off in high speed flight.
 

TomcatViP

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AeroFranz said:
mechanical transmission might be 98% efficient, with losses only in the gears.
Something that should be written stepping on toes when it come to Airbus. I am sorry but those little 2%... kill. This is why the angled transmission is a risk taken probably at the wrong time (to me at least).

@Coanda: nice to hear that you are free to innovate. Makes always the job more interesting on a personal point of view.

But having the possibility to oppose, critics or simply say no is old like the times and still ensure a sane design.
 

coanda

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AeroFranz said:
The joined wing probably allows a stiff structure without putting a lot of flat plate in the rotor downwash. It also looks cool...

As for electric cruise motors, by the time you've added generators and motors worth hundreds of kWs, the wiring, and speed controllers, you've got something much heavier than the equivalent mechanical transmission and with lower propulsive efficiency.

to put things in perspective, a mechanical transmission might be 98% efficient, with losses only in the gears.
The motors, generators, and controllers may each be about 95% efficient, throw in one percent loss in the wires, and you're below 80%.

The one place where it might pay off is the tail rotor. You get rid of the long transmission, and you can shut it off in high speed flight.
I would suggest that there so no need for the joined wing to create an appropriately stiff structure with today's materials. I grant you that flexing propshafts are never good....but to design an entire drag creating aero surface just to support a prop?! wow! they really want a prop shaft driven solution!!

I think the difference in weight is much lower than you suggest. that design has two more gearboxes in the wings!

Because of the above I would also doubt 98% efficient in real life.

But, we're not there and we don't know the compromises so it's all opinion really.

Tomcat - it's not always great but there is a desire for change in the right direction.
 

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Offered and disqualified shall we said. Evaluated and ranked even behind offers from small companies like Karem...
 

yasotay

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I suspect (fair or not I cannot say) that there are a number of export control laws that made it problematic.
 

TomcatViP

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Given that the US Army is the biggest military customer of Airbus helicopter, the why might just be a lack of ground for the claim of performances. Remember that Karem is in and Airbus not. Remember that no prototype was needed to enter the competition. And see how Airbus made such a late submission.
 

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Given that the US Army is the biggest military customer of Airbus helicopter, the why might just be a lack of ground for the claim of performances. Remember that Karem is in and Airbus not. Remember that no prototype was needed to enter the competition. And see how Airbus made such a late submission.
So you don't actually know why the Airbus entry wasn't selected.
 

TomcatViP

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Smith:
Wait. I've seen this. This is it. This is the end. Yes. You were laying right there, just like that. And I. . . I... I stand here, right here, and I'm supposed to say something. I say, "Everything that has a beginning has an end, Neo."
 

TomcatViP

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That's it?! Next time instead of quoting an epic 3 episode saga (apart from seemingly teaching you that being disqualified for sure means loosing) , I'll do with a cryptic shortcut silent movie.

Thank you for wasting our time.
 
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MihoshiK

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That's it?! Next time instead of quoting an epic 3 episode saga (apart from seemingly teaching you that being disqualified for sure means loosing) , I'll do with a cryptic shortcut silent movie.

Thank you for wasting our time.
Actually, that's my line. Because you make all these angry statements about Airbus without actually providing evidence. What did they do, did an Airbus exec once piss in your budweiser when you weren't looking? And if so, how did you taste the difference?

Also, at least have the common decency to quote people when you reply to them, so that they know they've been adressed.
 
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