Mad Genius - Wind powered vehicle travels 2.8x speed of the wind

[ducatiz]

Or invisible dwarfs pushing it, or a giant invisible magnet pulling it... or simply a wind powered vehicle.

you forgot to reply to the substantive part of my post:

and how do you know it was turning opposite to the torque from the air?  which way was the air torquing?

NALSA?  really?  a bunch of old farts who invent a sport in 1972 can't be bought? 

people worry about the FDA and the FBI, but nooooo.. when NALSA says something it much be holy writ!

[reksio]

Apply this to a soapbox derby car, you'd win everytime until either it was outlawed...

I assume that using wind power is already outlawed in soapbox races.

[reksio]

you forgot to reply to the substantive part of my post:

If you want to believe in some conspiracy theories, I won't stop you. From the physics standpoint there is no necessity to fake it.

[ducatiz]

Found another pic of a wind powered vehicle, not sure how fast they were going.

[Punx Clever]

You know, I threw my hand in this debate...  then I realized that the guy who ressurected it from the dead has only posted in this thread... then I stopped caring.

[Buckethead]

Found another pic of a wind powered vehicle, not sure how fast they were going.

[ducatiz]

You know, I threw my hand in this debate...  then I realized that the guy who ressurected it from the dead has only posted in this thread... then I stopped caring.

ding ding ding ding!

[reksio]

It could tack going downwind, and net velocity (velocity made good to sailboat folks) could be greater than windspeed. Maybe 50% more than windspeed....

Conventional sail craft on water can achieve a downwind-velocity-made-good of 2 x true windspeed. On land or ice it goes to above 3 x true windspeed.

Directly downwind at 2.8X windspeed, no way.

If you understand how tacking with downwind VMG greater than windspeed works, then it is very easy to understand this vehicle. The rotating propeller blades do the tacking, while the hull stays on a constant direct downwind course:

Sail_to_Prop.mov

[Statler]

I sail above windspeed occasionally.    I wouldn't call anything that does 2x windspeed "conventional".    And vmg?   Show me the boat that does 2x windspeed vmg to a downwind mark.   

I completely understand sailing and iceboating.  I even get that gybing downwind there will be (brief) periods of time when the boat is going Ddw faster than true windspeed before heading up to keep up speed. 

What's so difficult is that at windspeed Ddw there is no air moving across any part of your vehicle.  So that's a hump to get past in real life or in my head. 

Btw, what kind of bike you ride?   

[reksio]

I sail above windspeed occasionally.    I wouldn't call anything that does 2x windspeed "conventional".

On water it is not the normal case. On land and ice it is very common.

And vmg?  Show me the boat that does 2x windspeed vmg to a downwind mark.  

Quote from http://en.wikipedia.org/wiki/Sailing_faster_than_the_wind#Speed_made_good

It sailed 20 nautical miles (37 km) downwind in 1 hour 3 minutes, so its velocity made good downwind was about 2.5 times windspeed, consistent with being able to sail about 14 degrees off the apparent wind when sailing downwind.

Sources are linked in the article.

For ice boats see page 4 of:
http://www.nalsa.org/Articles/Cetus/Iceboat%20Sailing%20Performance-Cetus.pdf

I completely understand sailing and iceboating.  I even get that gybing downwind there will be (brief) periods of time when the boat is going Ddw faster than true windspeed before heading up to keep up speed.

The propeller blades do not need to gybe. They are on a continuous helical tack and never go DDW, just the hull goes DDW.

What's so difficult is that at windspeed Ddw there is no air moving across any part of your vehicle.

That is not true for the propeller blades which move relative to the hull.

So that's a hump to get past in real life or in my head.

You are used to sails which don't move continuously relative to the hull, and therefore experience the same apparent wind as the hull. Here the apparent wind at the airfoils is different and never zero.

[thought]

wired magazine this month has a great article on this... along controversy with all the people saying that it cant work even after the full scale model worked... haha

[ducatiz]

anyone get the idea this guy doesn't even own a bike at all?

[Punx Clever]

anyone get the idea this guy doesn't even own a bike at all?

Yup

[Vindingo]

anyone get the idea this guy doesn't even own a bike at all?

He is the guy with the funny hat in the begining of the desert video.  

[ducpainter]

Often...

if you stop feeding them they go away.