Talk-Polywell.org

http://d-dalus.com/en/home.html



An old idea with a modern, carbon-fiber twist.

(They just updated their website, so give them some slack w.r.t. website and translation glitches.)

Looks interesting. I wish them well. Yes, Skippy, I know they are Austrians.

ASME write-up:
http://www.asme.org/kb/news---articles/ ... he-horizon

Does this mean flying cars are just around the corner?

It appears to be an enhancement of this design:
http://www.youtube.com/watch?v=kgOAwzG9 ... re=related

(as referenced in the subject line).

randomencounter wrote:It appears to be an enhancement of this design:
http://www.youtube.com/watch?v=kgOAwzG9 ... re=related

(as referenced in the subject line).

Not quite the same concept. Fanwing does not do active, cyclic control of individual airfoil angles-of-attack, although there is some similarity in that both have a "fan" embedded in an airfoil-like shape.

Fanwing, however, depends on that embedding to function. D-Dalus does not, but is more efficient in forward flight if embedded. Fanwing also does not have the 3D control flexibility of D-Dalus, it is more about lift improvement.

http://www.fanwing.com/CEAS.pdf

choff wrote:Does this mean flying cars are just around the corner?

Before I climb aboard I'd want to know more about the new bearing design's failure modes (the original needle bearings were not adequate).

I'd also want to know more about bird/ice ingestion tolerance and power cross-coupling.

And then, the individual and collective blade-control failure modes (lockup, centrifugal, floating, damped, oscillatory, frictional spin, phase-loss, reverse...).

I remember reading about the first prototype a while ago. It was interesting, but then things went silent. If this is really that revolutionary, why arent there already licensing deals with aircraft manufacturers (that should be dying to get their hands on it)?
So I am little sceptical about the whole idea, Austrians or not

We don't know that there aren;t manufacturers lined up to produce various versions. This is just breaking news and the prototype self destructed during early testing. It is revolutionary though. So far as I know this is the first time (along with the fan-wing) that the Voith Schneider propeller has been used with air instead of water, and this novel iteration is a first. I would note though, there is no data about efficiency and it's very likely that this is extremely inefficient. It is certainly not an efficient use of the craft's mass and volume to have such a large drive system in the middle of the ship. You would have to need the super-maneuverability and stability this supposedly offers in order to justify such inefficiencies.

They claim that it is 60% more fuel efficient than a helicopter. Sounds quite outrageous a claim to me. I am also wondering where the passengers/cargo would go in the full size vehicle. In the wings, or inbetween the "wheels"? The latter might be quite loud...

GIThruster wrote:So far as I know this is the first time (along with the fan-wing) that the Voith Schneider propeller has been used with air instead of water, and this novel iteration is a first.

To repeat, Fanwing is not the same as Voith-Schneider. There is no cyclic control of angle-of-attack, or, if you prefer, blade incidence angle.

http://en.wikipedia.org/wiki/Voith_Schneider

Fanwing is an ordinary, fixed-incidence centrifugal fan embedded in an "airfoil" (although the flowfield with V_inf>0 makes the "centrifugal" adjective somewhat misleading). A minor variation has the blades slightly skewed to minimize noise as the moving blades pass the fixed structure.

Wondering what improvement might be obtained by, say, doubling the number of rotors (keeping the same total propulsor area) but with the flow going into smaller, higher-rpm rotors.

There must be some optimum compromise between number of rotors, rotor diameter/length, airfoil number/shape/chord, rpm, mass and power required for a given operational envelope.

I think that faster rotation would probably put even more strain on their bearings. I am sure however that they would be able to easily sort these out if there was a large enough industrial complex there adopting the technology. If this is as good as promised, I can already see the Generals lining up.

Skipjack wrote:I think that faster rotation would probably put even more strain on their bearings.

And the smaller diameter, less strain. Endless tradeoffs.

Some claims they state, to put the discussions straight:

- "30 to 60 % less power comparable to helicopter in forward flight" (just better in forward mode, not hovering)
- "very low noise level compared with helicopters" (noise is better than helicopters, but worse than planes)
http://d-dalus.com/en/home.html

- "friction free bearing at the points of high G force"
- "set driven at the same rpm by a conventional aero-engine"
http://d-dalus.com/en/features.html

An IAT21 patent, but not the bearing one.

http://www.google.com/patents?id=8ZjRAA ... 73&f=false

I think it needs a goose neck lamp sitting on top that shoots sparks.