*Our* video cut Jacks video up to fit our dialog. Jacks video is uncut: http://www.youtube.com/watch?v=aJpdWHFqHm0 The at the start of the video, the streamer blows to the front because is a tailwind. The streamer starts to hang and wander as the cart approaches and passes through the actual wind speed. The latter part of the video shows an extended period of time with the streamer towards the rear, demonstrating a headwind to the cart, while there is a tailwind to the road. The editing of Jacks video was done by us to fit our needs. Jacks video is unedited. Watch it and then come back with your new reasons. At the end there is near 2 minutes of streamer strongly back with about 2 seconds of streamer barely front -- surely you're not claiming that the whisper over the back propels that cart that far. I mean there are lots of things that could be propelling that cart -- many of which we mention in the video (downhill, string, etc), but I hardly see how you can claim that one whisper can keep the thing going for a full minute. Just as wind does not "blow through" a sail, wind is not blowing through the prop sail -- in both cases, it merely needs to blow *across* it to generate lift. When an ice-boat or a sail-boat reaches a VMG (velocity made good) of the wind speed, the sails on their craft do not hang limp. No, the apparent wind across the sail continues to accelerate the craft to an even greater speed (ice-boats, regularly achieve VMGs of 3x+ the wind speed). Tell that to the sailor who achieve it regularly Nope -- if what you were saying were true, traditional sailing craft would not achieve VMGs of even 1.0, let alone 3-4x. (I'll address your further comments next post) As to your your bolded comment: you and I couldn't agree more. JB
Haroki, I know this may sound silly on something so simple -- but you're pretty sharp to catch that above. Of the hundreds I have discussed this with, many say "windtunnel, windtunnel, windtunnel" without realizing that you would have to turn this device *around* and run it the 'wrong way' in the wind tunnel. Only a few have been bright enough to catch what you caught. Gotta run, but I'm enjoying the exchange and hope we can continue. We'll check back with you on that one after some more back and forth. See Ya' JB
Huh? Ok, so if you build a big one, and it is going faster than the wind, how can the tail wind get to it? If it goes as fast as the wind, it would be like it was sitting in still air to the person riding aboard it...and at that point...what would be powering it? SM
Well, first off a little one works just like a big one. That's exactly right if you are sitting on the cart chassis. However if you were sitting on the propsail you would feel lots of wind as the propsail is moving relative to the cart chassis. At any speed, the power comes not from wind relative to the cart, but wind relative to the ground. When the cart is moving the same speed as the wind, said wind is *still* moving relative to the ground. Since the have a 'hook' into each medium, we can extract energy from their relative motion. JB
Well, in the above exchange (all posted months ago), I don't believe I managed to convince a single person that it's possible to build a wind powered device that can go directly downwind, faster than the wind, powered only by the wind, steady state. Fair enough, but it IS possible and rather simple -- just unintuitive. In the ensuing period since the above posts, we have demonstrated this device many, many times for skads of skeptics (including many university professors, physicists, aero engineers, etc.). Tomorrow will be a fun day as we were invited by Stanford University to address the graduate student program from the Aero and ME departments, discussing and demonstrating the device to the Masters and Doctorate students and Professors. I got permission to video tape the presentation and the rights to distribute it -- I'll post it on youtube later today or tomorrow. After anyone who is interested views the presentation, perhaps you'll have a re-look at my position. Both the device and the testing methods have proven valid and are accepted by very bright minds in the field. Later. JB
http://www.fasterthanthewind.org/2010/03/sweet-success.html http://www.youtube.com/watch?v=7SYvg40NHtc http://www.youtube.com/watch?v=aDzWh9J1dk4 Entire San Jose State University project blog at www.fasterthanthewind.org
Pretty cool. Okay, I think I'm getting it. In the same way that a simple sail-powered device cannot move directly up wind, a propeller cart actually can move directly up wind. The prop-shaft-wheel arrangement can easily overcome the wind resistance. So when we move down wind, due to the curvature of the prop, the wind is tangent to the blade surfaces. With each rotation essentially 1/2 of its blade surfaces are up wind, and 1/2 are down wind. This allows the cart to "cheat" the wind and go faster than it down wind. At least, I think that's how it works!
Hi Wayne Actually, it's a *turbine* cart that can move directly upwind, rather than a propeller cart. Conversely a turbine cart can't exceed the speed of the wind while going dead downwind while a propeller cart can - different applications, different tools. It is true that because of it's spiral path, different stations of the propeller blades see a different apparent wind, but I don't think it's quite as you are imagining it. The prop is twisted so that at design speed, each station of the prop airfoil sees the same angle of attack even though the apparent wind comes from a different angle to each station. Thus the entire prop is attacking the apparent wind at the same angle. Once above windspeed, all portions of the propeller are seeing an apparent wind from in front quadrant of the vehicle. The part that catches most folks off guard is that the spinning airfoils are not acting as turbines and powering the wheels, but rather are acting as propeller blades and are *powered by* the wheels. It's a mind fuck because it looks so different, but actually is using the exact same principle that the BMW Oracle America's Cup boat uses to go faster than the wind. JB
Here's a recent write up in Sail Magazine (the issue will be on newstands in the next few weeks). http://sailmagazine.com/racing/running_faster_than_the_wind/ JB
What if tread mill will move very slow? Power generated by tread mill should be stronger than weight of your devise. If tread mill will not generate enough power device will not move faster so is it powered by the wind or tread mill? Try this take a bottle of your favorite drink close yourself in room. You can spend hours in the same room and nothing will change until you take a drink. But once you empty the bottle will it stay same? Still same amount of fluid in the same room. You can blow the air or pass the air either before or after taking a drink I can guaranty there will be difference. You are trying to prove that pull and push are same.