Directorly Downwind Faster than the Wind

[ramset]

Hmmm.....

A sail [propeller] going "across' the wind makes its own wind [apparent wind]

Thats why ice boats can go 5 times wind speed [chasing 200 mph record now]

no OU just some smart fellows having fun with apparent wind and a sail [propeller].
Have they gone upwind yet?[if not they will ,if they can limit losses enough]

Chet

[Cloxxki]

I read and watched what I could find on this topic yesterday.
Apparently, soon a DDWFTTW speed of 2+ times the wind speed, downwind, will be confirmed. Expected short-term records are expected around 3x wind speed.

It seems to be a matter of using the push of the wind, and minimizing friction.

Directly against the wind, Aeolus racers are working to be the first to reach 100% the wind speed, heading into it. Harder to reach than 2x downwind due to the match involved, but apparently the math does not offer a maximum speed to be attained, either away from or into the wind.

The way I simplify it for myself:
- Using a big fan to propel a tiny car. the mind breaking is that the big fan is ON the small car. And we need to remember that a spinning fan has a different drag than a garage door.

This research undertaken on private and corporate budgets is great towards making wind powered transport partly viable.
Seems that a car with a collapsible prop on the roof could be put to great use both in tail- and headwind to reduce fuel consumption. Sensors and GPS could automate this. Detect a significant headwind route, and deploy the prop to make the best of the situation. On a heavy bulky car efficiency levels will be lower, but it could prove worthwhile. I have some thoughts on sidewind mods for existing vehicles as well. Side wind really slows down a vehicle, sometimes more than headwind. Yet, sailors go faster in those conditions. So, deploy telescopic chimey air foils. Simple levers could on-the-fly adjust orientation. Deployment could be accomplished largely on wind power directly.
And, WHY would a parked car in a wind parking lot (aren't they all) not fill up some batteries while waiting for the owner to complete work or shopping? We can't place stationary windmills on parking lots, but a windmill is stealing nothing from anyone.

[hartiberlin]

Hi All,
it has nothing to do with the wind !

Look at the videos on the automatic exercise treeadmill belt.
There is NO WIND !

But the vehicle drives faster than the treadmill belt !

It has in my opinion to do with the gearing
of the propellor to the wheels and with the
inertia of the propellor mass and the wheels.

Somehow the gearing transmission factors must be right
to the thrust the propellor is generating from the rotation.

Regards, Stefan.

[hartiberlin]

They just posted new videos:

See for example this one:
http://www.youtube.com/watch?v=86vhmTp7tKU

There the truck pushing it to start drives just 14 miles/hour but the vehicles just accelerates faster than it.

So you see, it is selfaccelerating and also drives faster than the wind !

[ramset]

Stefan
Quote:

"Look at the videos on the automatic exercise treeadmill belt.
There is NO WIND !"
-----------------------------------
Ouch!!
That hurts my head!
hard to get your brain around that.
So this is no hoax [the treadmill]!

Seems impossible !
Although I know it is, having sailed my 38 foot catamaran race boat at almost twice wind speed any time I want ,with almost 80 foot of hull dragging along in the water.

Only stands to reason something like this is possible with the proper
set up .
Whats next ?flying without a motor?
"Apparent wind "
WOW!!
Thanks ,Its good to see someone think this far out of the box
And get seemingly impossible results!

Chet
PS
Looks like we'll be putting propellers on the race boats [sail]