Directorly Downwind Faster than the Wind

[ramset]

Clo
Well one thing is for sure.
Something very cool is going on with this.

And that setup is doing work, beyond what is expected !
Way beyond!

I don't understand it [yet].
But I like it !

Chet
PS
Clo
I don't know if its good or bad ?
but I understand "most" of what you say! 
I'm quite sure you are going to come up with something
that I will just have to try!

Remember "dirty air" [prop wash]
every prop needs to be in clean air!

                             

[BEP]

What about a tailwind powered hovercraft. Could it be done?

Hovercraft... These are a passion of mine. That would be great.
The way I understand this, the craft would need one or more wheels on the ground and couldn't exceed much more than 2x wind speed. Using ground-effect a lot of lift surface area would be needed.

Interesting thought.

[Cloxxki]

Hovercraft... These are a passion of mine. That would be great.
The way I understand this, the craft would need one or more wheels on the ground and couldn't exceed much more than 2x wind speed. Using ground-effect a lot of lift surface area would be needed.

Interesting thought.

I would be interested to know how much power of a hovercraft's engines (I never saw one in person) is required to properly fill the air cushion, and create the frictionless interface. I suppose surface and weight (psi?) would be a main factor? Still, a hovercraft is supposed to be an efficient (for payload, fuel consumption and speed) form of water transport, correct?

I have a bit of an obsession for ground effect. I want a human powered ground effect wing, that is faster and more manoeuvrable than the existing Channel-crossing biplane type fly-zilla's. It's all about surface to weight I suppose here also. Thus, a matter of efficient engineering.
Unfortunately with an airborne craft, it's hard to drive the prop with a hard fix on the ground speed, to gear it over the apparent headwind, and get forward thrust.

@Ramset : if this stuff fascinates you, and you are not shy for a build project, this seems like great fun. It can always entertain friends. Just keep some balloon on hand to make speed comparisons. Hey, you might earn back your time in bet wins!
Don't expect to build a cart that will ride by itself day and night, as really, it needs wind, preferably tail wind.

[ramset]

Clo
Hover craft is a fuel pig!

Ground effect!
Now your talkin, get a plane off the ground [or a boat off the water].
Cut back the throttle 70% in ground effect!
Yes a passion of mine also!

Chet

[Cloxxki]

Clo
Hover craft is a fuel pig!

Ground effect!
Now your talkin, get a plane off the ground [or a boat off the water].
Cut back the throttle 70% in ground effect!
Yes a passion of mine also!

Chet

Thanks for the heads-up Chet, fuel pigness reduces hovercrafts back to toys for me :-)
It bugs me that the firm surface-craft traction is required to leverage the power of the tailwind. What's a ground effect wing worth when it drags a pizza cutter to power the prop that keeps it flying?

I just thought that a ground effect wing could feature 2 opposing airfoil chimneys, to possibly negate the lateral drifting, and need for a draggy keel. For the aerodynamics lover that would a fun project, build a wing from styrofoam (sp) or paper mash, and put paper airfoils on it. Make the design adjustable to find a sweet spot. RC the controls. It might work, or it might not, I am not well read into the wind scene.

I am still strugling with my own mind teaser. Can gravity's pull be used to get the part rolling, and can the turning wheel be used to drive an over-geared prop, to give nett thrust that sends the cart accelerating past gravity-only power, in still wind? Or do the wheel feel a braking force (to power the over-geared prop) that surpasses the thrust a prop can offer at any given speed? If a gain can be had, that make it a perpetuum mobile for me. Use wind drag (reversed in the prop) as a power source. All my life I've been thinking about how drag could be reversed. Might this be it? The aeolus racers fought against the wind inching straight into it, not even trying to use it to triple their speed downwind. Now, the signs are that 4x the wind speed may soon be achieved by a prop cart. So, could "tail wind" be replaced by "gravity" as power source? A gravity power generator that relies on the viscosity of air? A man can dream, right? Certainly on here.

Anyone know how good aerodynamic modelling programs are lately? In the relative (to aerospace) low wind speeds that wind powered carts encounter, some extreme prop layouts might be tried to maximize thrust.