Stay out of ISAF, as we have done so far, and allow 3D sails ?



Gee Macca, I don't even need more then 3 seconds to put effective replies to your posts.

You are losing this debate if you don't play it a whole lot smarter.

Wouter

So, I'm off to do some work now.

Macca, use this timeframe of several hours to think up a better strategy because I'm getting bored with your soft punches.

Wouter

I have already won, and anyone else who reads this will agree.

The important fact here is that Wouter is no longer an official F16 office bearer & therefore would not be the person(or part of the committee that would decide)on weather F16 wants to become ISAF recognised.

So thats a useless conversation/ debate to have in my opinion.

Dear Wouter,

The word modest pretty much says it all doesn't it? <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />
Dictionary: Modest: Moderate or limited in size, quantity, or range.

ISAF said so, a Judge has said so, so pull out the white flag and/or give it a rest.

"I can run circles around Macca even when drunk.

And give everybody an illustrated course on debating techniques at the same time.

Ohhh YEAH !

Wouter "


WHo the fek are you kidding ??????? only yourself !

Wouter you are a tit !!!!! the sooner you realise it the better

Theres some good Scottish rhetoric for you !

No committee can decide whether "the F16 class want to go ISAF" either, that is a members vote thingy !

Wouter

Macca, just declare victory and go home, right ?

I can live with that.

All concluded then ?

Wouter

Just what the hell are you drinking (or smoking) W? <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/mad.gif" alt="" />

I don't even sail an f-16, but I like to come to this side of the forum because there is usually some pretty entertaining stuff to read. This thread has been awesome!!! All that's left for Wouter and Macca to do now is pull out the rulers and find out who really is the better man!

Wouter, hopefully in the future you will be a little more open to the possibility that you are not always right, and restrain yourself from bluffing your way through a topic with theories and hypothesies.

I look forward to seeing you at a regatta in Holland this year (if you go to regattas)

I won't be going much to regatta's this year at all I'm afraid. I got a research project starting on 1 march and I have to complete that in 12 months, and that is tight.

Before that time I still got to complete a full dynamic simulation model of a Harbour Crane for sea containers and implement it. I'll be very busy for the next few months and be lucky if I take my boat out of storage before mid summer.

I wish you the very best at the regatta's next year.

Signing off,

Wouter

What is your project about? Would be fun to know what you will spend 12 months of your life on.

Still have to receive the final get go but it deals with, ... wait for it :

Active damping of vibrations in very large wind turbines using the smart rotor concept.

See picture :



We are talking about wind turbines that have a rotor diameter of over 100 meters, here the vibrations (even small ones) are becoming quite problematic. They distroy highly loaded parts like the bearings rather quickly and now these turbines have to be shut down when the wind is not quite right, to safe some lifespan of the bearings for perfect wind days. By reducing these vibrations it is intended to increase the lifespan of the highly loaded parts to such an extend that these turbines can just be left on for very long periods of time between maintaince or repair jobs. This is very important economically. The more hours such an expensive turbine can produce energy the quicker the investment is won back and the more interesting it becomes to invest in one and the more the price per KWh reduces.

I'm going to try to get a new type of actuator (to move the control flaps) to work well. This actuator uses memory metal to move the flap and that is a highly non linear and non repetitive actuator. My task will be to design and implement a compensator that will remove all these non-linearities from its behaviour when the combination of compensator and actuator are viewed as a single blackbox. Some of this non-linearities will be linked to the aerodynamic behaviour of the flap itself.

My initial expectation is to do this using an Artificial Neural Network (multi-input ; single-output) fed with all the influence factors and having trained itself to compensate for them.

Everything is intended to go into a windtunnel setup to be tested. Sadly the (old) test setup came loose and was distroyed in the windtunnel some months ago. So somebody has to build a complete new setup before we can proceed on that, but arrangements are being made to that effect.

I would really love to be there when part of my work is tested with that of others in the windtunnel.

Wouter

Sounds like very interesting stuff! If the project goes awry, remember your emergency exit: Build the blades out of cold moulded wood veneers with a 7% carbon laminate added. Should solve the problem you are trying to fix <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />
Or drop the thing into the ocean where the currents are more predictable and not so violent. Of course, just dropping it into the deepest part of the sea would also solve the problem, kind of..

Good luck with it! If I see such systems in production in 10 years I'll let everybody around me know that the guy who designed that system also sail catamarans.

Not really Rolf,

It is not the weight of the blades that is the core of the problem but the aerodynamic forces on the Blades. Can't solve that by choosing a different material.

Think of it in this way. When a rotor has a diameter of over 100 meters then the gust at ground level doesn't have that much correlation to the windspeed at 170 meters above the ground. The support structure for the Rotor being at least 70 mtr tall itself.

So one can easily see how the load situation on the rotor is assymetric and changing all the time. We are talking about 5 to 10 MW energy production and that means "I don't know how many" tons of aerodyamic pressure on the blades at basically tens of meters of leverage arms.

Ocean currents are more stable I guess but also alot more slow. You pretty much have to find an underwater gorge somewhere with an accellerated current running through it to sufficiently offset the drag incurred by the turning rotor and come out with a net energy production.

Anyway, we are not going to start another topic about theories and hypotheses right ?



Make that " ... also sails F16 catamarans" !

Why not get some promotion out of it as well. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />


See Ya all.

Wouter

Wouter, I have often wondered why they don't use smaller diameter blades, but put more of them up and down the support tower, so they are all operating in their own little wind speed, not covering the huge difference from 20M height to 120M height.

Why not put 5 smaller ones, say 20M diameter each, up a tower, each able to swivel into it's own wind, as not only the speed but also the direction of the wind changes in that 120M altitude. I know they wouldn't produce as much juice as one big one, but they would be MUCH cheaper to build, able to operate at much higher windspeeds, and you wouldn't have all the vibration problems...and you wouldn't have to shut them down when things aren't "perfect" so you actually might end up with MORE juice (electricity) in the long run. <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />

Mate, you are going to get him going now, but actually interested in what he has to say. One area that I am in at work invests in Clean Tech/Clean Water so see heaps of research on these type of companies. All in the Asian region (specifically China, India etc). Certainly an interesting space. These type of companies have been bashed in the past few months with their stock prices, but I could go on about that, but no essays from me today.

The underlaying reason is called "Kyoto" and "100 dollar oil prices"

The direct reason is "cost" and "energy-yield"

One rotor of 100 mtr diameter covers an (swept) area of 7854 sq. mtr. (= 100%)

5 rotors of 20 mtr diameter cover a combined (swept) area of 1571 sq. mtr (= 20%)


The energy yield is roughly proportional to the swept area; meaning that a large rotor can produce about 5 times as much energy then 5 smaller rotors using the same 100 mtr tall mast.

Note however that we are still mainly using about 75 mtr tall masts, so we can't fit 5 rotor of 20mtr in there while we can fit one 100 mtr rotor. On a 75 mtr tall mast you can only three 20 mtr rotors installed and have only 3/5*20% = 12 % of the energy yield which is peanuts. Actually the produced energy is even lower as a series of smaller rotors suffers much more from the windshadow of the tower then a single large rotor does.


Both Kyoto and other renewable energy agreements require nations to produce something like 20% of their anual electricity usage from C02 neutral means by 2020 if I remember correctly. That is a whole lot of installed power. It is much easier to achieve that using big rotors then small rotors.

Additionally, we have to get off-shore with these windpark in North-West Europe as we are too densely populated on land and our best wind in found on the seas. Putting down a foundation on the seabed to take the support tower and installing the tower is very large component of the total cost. Entlarging the rotor diameter isn't. That is why everybody is looking to make the largest wind turbines that we can. Because then the cost per produced KWh is the lowest. And of course KWh is what you are selling in the end. Meaning that when you have more of it, you can get more money back in return. One very important consideration to investors.

But we must also not forget that having 5 small rotors with their own drive shafts, bearing and generators is not cheaper then one large rotor with one big drive shaft and one big generator. I haven't seen such comparisons myself but I would be really surprised if 5 smaller rotor would come in cheaper then 1 large one. And that takes away the single argument that the small rotors had going for them.

So summerizing : Small rotors are just not economically attractive as the investments per installed KWh are too high, leading to far too long "return of investment" times. This is one area where indeed "advantages of scale" are to be found.

There are also several other more technical reasons but I won't bore you with those.

Wouter

Wouter,
When in Zandvoort in August I noticed a wind farm off shore to the north. I didn't notice it back in 2004. Doesn't mean it wasn't there, but I didn't notice it.
Do you know when that went in and are there more planned.
It would be a lot nicer if they could put something similar under the water and use the current that is generated up and down the cost by the tide movement.