'Sailing'?? Directly to Windward

Gonzo, I haven't said anything about whether English is your first language, but if it isn't, maybe that explains why you fail to get my point, which is that your nitpicking on a small point of semantics is disparaging and is distracting attention from the substance of SpiritAmsterdam's posts. Of course, I never should have engaged you about it, because my doing so is just causing more distraction.

So, everybody, please ignore these asides and go back a few posts and read what SpiritAmsterdam has to say.

 

I think Gonzo gave very reasonable advice to the organisers of the contest.
In mathematical form:
> 100% efficiency => crackpot.
QED.

 

Interesting. I didn't know that about the Blackbird! With our vehicle we can store all the energy we want as long as that energy is only generated during the run and not before! Flywheels batteries and stuff like that need to be empty (not store energy) before the run.

Our vehicles don't have a fixed transmittion. In 2008 there were a few vehicles with fixed transmittion but this practace has not been continued since then. All the vehicles now have a variable transmittion. The Spirit of Amsterdam 1 has 6 different gears. And the Spirit of Amsterdam 2 has 28 different gears. (That is why all gear shifting in the spirit 2 is done by a computer because it is to complex for the driver to shift 28 gears over 2 drivetrains)

Just like with the Blackbird and other DDWFTTW vehicles there are allot of sceptics about the subject. People can't seem to imagine that it is possible to travel faster then the wind strait into the wind. People don't understand that the wind has allot of potential energy and that this energy only increases when driving into the wind.

Thank you.



ps: To all critics about the termonalogy: I am not here to discus sementics. English is not my native language and neither it it the native language of the event organizers! As you could have read in post #129 in the first paragraph (just after my introduction) i explaned the proces of calculating the efficency of the vehicle. You could have read that this was about the vehicle speed vs windspeed, so next time read more carfully! What you all should know is that this is a race between vehicles and not between turbines. So all the termonalogy is based from that point of view.
From now on i will not continue the discussion about efficency or its termonalogy/semantics and i ask you to do the same, because you will only be repeating what has already been said! I will contain my reply's to the subject of Wind powered vehicles and its questions about the event. So if there are any questions related to those 2 subjects or if you don't understand my explanation, then i will try to awnser them as best as i can.

With kind regards,

Ingmar Hendriks

 

Please stop the semantic nitpicking. There were no false claims made as it was explained very well in SpiritAmsterdam's very first and following posts what the WPV race organisation means by "efficiency" in regards to WPV's. And yes it differs from the general understanding of efficiency. If you read "efficiency" of a WPV, please translate it in your head into "ratio of wind speed vs vehicle speed" as it was explained it was meant that way in this case. Never the less everybody is free to use the correct term "ratio of wind speed vs vehicle speed" but also everybody is asked to understand the term "efficiency" of a WPV as such, and don't kill valuable information sharing over it while was explained what was meant.

Ingmar, thanks for joining the forum and sharing all this information

Good luck with the project, and have succes

Cheers,
Angel

 

Using wrong terminology caused all this confusiong and killed valuable information sharing. Why so much resistance to standard definitions?

 

Ingmar,

I will try to keep this technical and hope that no terminology police come after me.

Based on your posts, the electric drive option seems to be getting serious study.

Are the basic major components (generator, motor, major portions of the electrical conversion) for the electric dive vehicles more "off the self" items, or are they specialty components (ie, "very high efficiency" purchased items, or custom made items by competitors).

I am interested to see if the general interest in electric and/or hybrid power in the automotive or even the small scale wind generation industry is creating more in the way a mass produced items that have better efficiency and other features important to electric drive systems.

I have also been thinking about the shrouds around the turbines. I can easily see how they add to the power generation ability. However, has there been really good assessments to confirm that they do not result in a net wash due to extra overall air drag that is generated.

 

Development of lighter higher gauss magnets have created the possibility of more efficient electric motors.

 

I was aware that strong permanent magnets made a big deal in the advance of small motors. Specifically, I remember when the new "super magnets" (Neodymium I think) were a big deal in the miniaturization of hard drives and computer CD drives. I am not sure I recall seeing any of this technology in motors that are big enough for the subject matter at hand.

I also know that power conversion technology has made a lot of advances in some areas.

Where I was going was more focused was to see how much these kinds of improvements have trickled down into the supply chains. As better stuff becomes more readily available across a large range of size and without any huge cost premium, electric applications start to become a reasonable choice for items that used to not make any sense at all.

 

Trolling motors and electric motor replacement for internal combustion are common.

 

Electric RC helicopters are becoming more of a norm - used to be gas only for any decent sized craft. Electric bicycles are relatively common and motorcycles start to be somewhat viable. There are some electric para gliders - at least DIY solutions. The selection for battery operated power tools has never been as big as these days.

In addition to the availability of cheap and powerful motors the recent advances in lithium batteries have played a huge role.

So the electric revolutions is definitely affecting certain products/markets.


However I have hard time seeing how electric powertrain could be more efficient in this kind of setup. I might be wrong but seems that its hard to keep the efficiency high through the whole chain:
generator -> controller -> Motor -> final drive

While there are components that can be very efficient they often are that in relatively narrow range. Am I wrong to think that you need some kind of motor controller even if you are trying to pass all juice to the motor?

 

Vertical axis wind turbines tend to be heavier than prop-types, but they have some advantages in some circumstances.
Has anyone tried them in downwind racing?

 

In order to get the most out of our electrical vehicle a sertain amount of components are bought. However some parts have to be made in the labs and facilities we have at our universitiy. I am not talking about small components like resistors or microcontrollers (those we just buy and then assemble with our design).
But i am talking about a generator and the electrical engines (we have 2), those we bought. However we did that this year because production time of our home made engine was to long and couldnot be finished before the race. Therefor we used an engine that is available to everybody (A golden motor Magic Pie engine). This engine has an effenciency (im talking about the engine here!) of 85%. This effenciency is high enought for most commercial applications (they are easy to make, production costs are low, and quality is good enought). However this is not good enought for us. We used this engine mainly because of timeconstraints, but about 3 months ago another team has started the design, production and testing of our own made halbach engine.

A halbach engine is more complex and allot more expensive to produce but it has an efficentcy around 94% to 98%. These are the kind of engines that the solar vehicles use in the nuon solar challenge in Australia. There aren't allot of engines available on the market who use the halbach array pricipal in an engine. And those who are available didn't have the specifications we needed. So we decided to make our own. We hope that we can have a working model before May 2012.

The design and production of this engine is done by a seperate research team (about 12 sudents with 3 teachers, i think) within our university. The reason that this is a different team is because the production of this engine could also benefit the other race research projects we have at our university. We also have a vehicle that drives on hydrogen energy (www.h2a.nu) for the Eco Shell Marathon race in Europe and a solar boat for the dong solar challenge in the Netherlands.

One of our sponsors of the spirit of amsterdam project is DonQi. DonQi is a manufacturor of urban windmills. For the last 3 year Donqi and the research team at our university have been cooperating in the design of there windmill. See http://donqi.nl/en.html There have been extensive wind tunnel testing in order to perfect the design.

Yes it is true that the air drag is higher with these shrouds around the turbine, but in low winds the extra drag that is created is not more than the extra power benefits. For a WPV this drag is not a good thing, that is why we use are own made turbine that is similar to the turbine from DonQi but is just a little bit different + our turbine is only 22Kg and the turbine from Donqi is made from more durable matirials that wheigh over 80Kg. For a staitionary turbine this drag and wieght is not important.

 

There are some teams who use a vertical axis wind turbine in the race. However a vertical wind turbine operates more on the principle of drag than on aerodynamic lift. Since 2008 there has been at least one team with a vertical turbine. But those turbines are not really that good on a WPV. Those vehicles don't need a system to put the turbine in its correct orientation in the wind and they are therefore easier to make so there are benefits to this but they are just not as powerful as a turbine is.

There is a vertical turbine WPV in the middle of this picture:
http://2.bp.blogspot.com/-_xn_hZGEQHA/TtIIBL79VxI/AAAAAAAADlg/osWfsWZBKiE/s760/DSC00290-pan.jpg

Our turbine can produce about 350W in a 5 meter per second wind and in a 18 meter per second wind this is 7 KiloWatts. I would like to see a similar sized vertical turbine produce the same power, it would make it allot easier for us if this were the case!

 

That is true of the Savonius type (which are almost pure drag devices) but it is definitely
not true for Darrieus-type which depend on lift rather than drag.
A Cyclo-giro arrangement could be "tuned" for the conditions of the race.
See for example:
"Three Pitch Control Systems for Vertical Axis Wind Turbines Compared"
http://www.cyberiad.net/library/pdf/we1992_16_5.pdf
and other papers on the page at:
http://www.cyberiad.net/vawt.htm

That's quite good. I would have to do some work to design the pitching system for a VAWT at those speeds. Maybe when there are 30 hours in one day!

All the best,
Leo.

 

Because the wrong term "vehicle efficiency" for "ratio of wind speed vs vehicle speed" has become common jargon within the WPV community since the organizers of the competition have incorporated this wrong terminology in their regulatory it seems. If so, best to change it at the source (someone could make a sugestion to the WPV race organisation), meanwhile I suggest we understand it as explained and not chase away the only member of the WPV community we have here and who has much to share.

Good advice - - - (I should have taken it earlier )

Cheers,
Angel