DDWFTTW - Directly Downwind Faster Than The Wind

http://www.fasterthanthewind.org/ Looks like only bit of assembling left.. ?

 

At the moment JB is working on the spinning components (wheels, axles, prop-shaft, bearings, brakes, prop-hub, etc.), while I'm working on instrumentation. We want to log and display prop torque, thrust, and pitch from the rotating prop, plus 3 sensors for wind speed and direction, as well as prop RPM, and axle load (in direction of travel). The prop is very nearly ready to go. I want to take one last pass on a few areas we blew, and touch up with paint and primer. I'd love to wrap the prop up this weekend and start parking in my garage again.

We're highly motivated to get some first test runs done by the end of March.

 

Where will it be run? How will you document the conditions and the runs, especially the speed of the wind and the machine?

 

We hope to bring it to the NALSA (north american land sailing association) event in Vegas. We will have a good deal of instrumentation on the vehicle, chase car, and land. This will include pitot tubes, weather vanes, load-cells, GPS, RPM sensors...

 

I hope it's a wide open space with no obstructions and a steady wind with no gusts. What sounds to me like a good marker of wind direction and speed and whether the vehicle is going directly downwind and faster than the wind, would be smoke. Something like those colored locator smoke bombs. Good luck.

 

A "steady" wind does not exist!

There's no such thing as wind without gusts.
The natural wind varies all the time.
If you can indicate any data that suggests there is such a thing as a "steady" wind, then I would like you to point me to it.

Some BIG mistakes have been made in sailing where design has been based on wind-tunnel data, which is fine for aircraft (which fly at a steady speed) but inappropriate for wind-driven boats, where the wind is mostly varying by up to 50 percent.
Actually, I'm thinking of Team Philips where the boat couldn't stand up the bashing if got in real-life as opposed to the theory.

Sorry!!! I think I have digressed from the thread a little!

 

After more than four months of work building essentially all from scratch (including the 17ft propeller and load cell instrumented prop hub and drivetrain), today was assembly day.

Next weekend the rig will get dyno tested and is scheduled to be on a Nevada lakebed in 3 weeks for shakedown testing and to meet with NALSA to work out the final details of their instrumentation for the cart and record ratification.

We're going for 2x the windspeed.

www.fasterthanthewind.org

 

I have been watching the painstaking process of building it. I admire the effort.

A lot of effort for something that has no real use beyond proving a point.

Imagine how uninteresting life will be once you have proven the point. I wonder what all the flat earthers are going to say. I expect they will never concede. Will be looking for your battery pack.

Rick W

 

There are several other things we'd love to get around to doing. Boring isn't likely to be a problem.

There are a few that I'm quite certain will never concede. But I sure hope the aerodynamicists and physicists do.

 

You cannot be sure something will have no real use. Hasn't history proven that many things, discovered in the name of pure research, with no obvious benefit, have later found their place and been very useful? Proving something that was thought to be impossible is a reward in itself. Could the Wright brothers have foreseen Concorde? or Faraday foreseen the Internet? The process of discovery is a process of building one thing upon another bit by bit like building bricks in a wall.
At the very least, the discoverers name will be recorded in history (get mentioned on Wikipedia! )
David Bauer was slowing sinking into obscurity, but now his name is well known amongst those who study these things.

 

The only use we *intend* for it to have is:
1) to keep us occuppied during the non-windy season.
2) To demonstrate that it's a bad idea to try and substitute intuition for science.

However, it does have some interesting aspects. One such aspect is the somewhat bizarre outcome that you can theoretically harness an unbounded amount of energy from the wind - if your windmill is allowed to move through the wind. A traditional windmill has a very definite limit to the amount of power it can produce for a given amount of wind. However, a moving windmill can continue to produce more power as it moves itself through the wind.

It's hard to say whether this will become any sort of practical reality, but there are folks using the principle - including our sponsor Joby Energy.

I think you mean Andrew Bauer.

 

Obviously his name is not known well enough yet!!!!

 

I agree with the statement but it does not apply here.

The basic principles are nothing new and can be easily understood by anyone who cares to understand them. Many people jump to a conclusion and then pride gets in the way of true understanding - they remain sceptics.

The aim of the exercise is not discovery - that was done many years ago. It is to give more compelling evidence to people who lack the ability to work from first principles. However I cannot see why this will overcome the scepticism when smaller models did not turn the lights on for the sceptics. The large scale cart being built has nothing different to the smaller models.

This idea has been around for 30 years or more. If it is not in regular use after that time you can bet that it will remain a curiosity. There is nothing new in the science.

The Wright brothers may not have contemplated Jumbo jets but they knew they had achieved something of great importance. It did not take long before the importance of human flight was widely recognised. It advanced rapidly and dramatically. Similar results for light globe, radio, TV and a myriad of other "discoveries".

The typical timeframe from a discovery to common use is 30 years. If it has not caught on by then and undergoing rapid development it won't.

The physics limit the value of this discovery to a curiosity.

Rick W

 

I agree the cart can extract more power as it goes faster but there are also greater losses in moving the cart. There may be some speed where you can extract more power than a fixed turbine but there is a limit that is constrained by the system efficiency.

I expect it would be more advantageous to extract excess energy to move into the wind rather than downwind. The turbine blades in this condition are in a more favourable regime and do not need to be as big.

Rick W

 

Only somewhat. We realized long before we started building the big cart that there are those that will not accept it ever - under any circumstances.

It doesn't add anything from a physics point of view - but then neither does demonstrating it outside in "natural" wind vs. indoors on the treadmill. But it seemed like a fun thing to do. That combined with the fact that Joby and Google are paying for the materials, makes it an easy choice.

The North American Land Sailing Association is developing a records category for DDWFTTW as a result. Clearly they wouldn't do that for our little carts on the treadmill.

Quite possibly. But I see potential applications in generating electricity from wind. Others are already spending millions on it, so they must think it has some promise.