Lessons in carbon fiber laying: Boeing 787

[xpensive]

Just a piece of advise WB, when you are discussing with engineers, cracking some realistic numbers would give you far more credibility than just airing opinions.

A "5 MW" wind-turbine, refers to the installed generator's max power-output, which typicaly occurs at a wind-speed of 12 m/s. Sadly however, the wind-power has a cubic relation to said wind-speed, why at 6 m/s there's only 625 kW left.
All in all, the typical efficiency of a wind-turbine is 30% of the installed power, why an average output of 1500 kW is what can be produced from a contraption such as the above.

Now, how agout your Singapore night race, just how many kW of power was connected to the light-arrangement, surely you have that number available?

[WhiteBlue]

I remember a figure of 3.2 or 3.4 MW for Singapore. While it is true that wind isn't always powering wind turbines at max power you can get pretty good average figures at prime spots off shore, where a lot of the capacity is now allocated.

The fact remains that renewable sources of power are growing at a nice pace and will make a bigger contribution in the future.

The biggest "source" for the future remains efficiency improvment. Aren't we going abit off topic? Perhaps we can revive on of the many threads about alternative energy of the past. I'd love to go back to algae and see what you make of that.

viewtopic.php?f=1&t=4294&hilit=algae&start=45
viewtopic.php?f=3&t=5577
viewtopic.php?f=3&t=5556

[G-Rock]

Question: How much does a nuclear powerplant cost?
Answer: No one really knows until it's been running for ten years. Here in Ontario Canada, our nuclear industry has posted another one billion dollar shortfall that we the taxpayers have to pay for. On top of that, one every electricity bill we have to pay an extra 4 - 6 dollars per household/month for the next 10 years to pay for project cost overruns from the 1980s.

It's easy to price out renewables such as wind because like a water dam, the price of wind never changes. Water is water, wind is wind and sun is sun. The only thing that can make the cost of renewables cheaper is more innovation, especially in energy storage that can be released during peak usuage hours.

I think that to save cost's for Singapore next year, F1 cars should just have headlights mounted on there ugly front wings.

[Conceptual]

Here in the US we can overcome that problem by simply decomissioning nuclear submarines.

[xpensive]

What, cost overruns in public Canadian projects, you gotta be kidding?
Having lived in Montreal, the Olympic stadium suddenly springs to mind...

Right, still on the subject, the problem with wind-power is the low energy content of it, which is due to the equally low density of air, one per mille of water's.
This is why a "5 MW" windmill needs a diameter of 140 m (460 feet) at a windspeed of 12 m/s (27 mph) to produce its full power, while on average, 30% (1500 kW) around the year is a typical assumption.

The cost of erecting such a contraption is in the region of 15 MEUR (20 MUSD).

Not know knowing the details in NA, but here in Sweden we have some 25 year old nuclear reactors, long time paid for, still pumping out 1200 MW each. That's printing money.

[xpensive]

Conclusively, which I tried to make technically plausible, you would need two wind-mills, each with a diameter of 140 m, together with a continous wind-speed of 8 m/s to feed the lights of the Singapore GP.

[Ciro Pabón]

People, on thread or else.

[xpensive]

Else please, whatever that means now?

[Ciro Pabón]

It means that I shall split the thread, xp. Or maybe I'll send the Internet Hit Squad to your home, to arrest you for being caught in OOT flagrancy.

Seriously, please, you are free to open new threads, let's help Tomba in keeping the site more or less organized. Altough I happily confess I go OOT, I try to declare it and end my posts with at least a vague reference to the topic...

Last time I checked, this site appears at the top of many google searches: the world is watching you (and of course, the Internet Hit Squad is connected to your IP address, since I warned them after my last post).

For example:

I go OOT by commenting that Colombia has created a wind farm in La Guajira, among wayuú indian territory. The numbers fit nicely with xpensive figures (1.3 MWatts for each turbine, minimum wind speed: 4 m/s, average speed: 9.2 m/s at 50 m of height, blade diameter: 60 m). They allow you to get credits for greenhouse emmision reduction: http://cdm.unfccc.int/UserManagement/Fi ... GZ5ENB1PT3

Back on thread, have you seen the new turbine blades in carbon fiber? Starting at 70 dollars each, they are guaranteed for life:

Carbon fiber wind turbine tips:


The manufacturer claims they don't degrade with UV light. Does anybody knows if CF degrades normally with sunlight? That would be a good reason to race at night...

[xpensive]

Point taken, Ciro,
I don't recall hearing CF itself having any problem, however the matrix might, in particular Thermoplastics. Polycarbonate (PC) should make for a great matrix, but is very suceptible to UV.

Regarding your LaGuajira wind-turbine, theoretically, with Power as dynamic wind-pressure times volumetric flow, a 60 m turbine at 9.2 m/s will generate 0.60 MW if the efficiency ratio is the for a wind-mill typical 50 %, but 1.35 MW at 12 m/s.

Ain't engineering a blast sometimes?

[humble sabot]

Not to be jerk, but poly carbonate is a very general term. It really just means several molecules of lots of carbon atoms coupled with three oxygen atoms each. Gut instinct tells me the chemistry maybe problematic as a matrix for high performance carbon fiber structures. But i'm no chemist.
Epoxy resins are most common, and while somewhat better (better always depends on application) than polyester types, or polyurethane, it does require, at least for extended outdoor use, UV inhibitors, be it a paint coat, or resin additives to the topcoat.

[speedrcr]

Environmental effects are not limited to UV exposure. As a matter of fact, UV has the smallest effect on the laminate matrix strength of all environmental factors. Moisture absorption being the primary factor in matrix degradation, with temperature following. There is a research paper which I think is in the public domain which presents this data in a concise manner. Also remember, that when designing a laminate, you don't want to be matrix critical. In other words, if a +/-45 fabric laminate is failing due to axial loads, then one would expect to add 0 degree plies to react this strain.

[flynfrog]

If you want some good reading pick up US Military hand book 17 volumes 1-3 should give you a good start.

[riff_raff]

That Airbus report that Ciro linked is the dirty little secret that has long been known in aerospace. Mass producing high-performance composite structures is not currently possible, even with highly automated machinery.

For composite aircraft structures, the lay-up needs to be accurate and consistent from part to part to guarantee quality and reliability. To do this quickly requires automated tape laying machines. But even the fastest machines currently available are still too slow. The only way to speed up production would be to build duplicate tools and machines, but that would be cost prohibitive. And the situation for more cost-sensitive, high volume applications like automobiles, is even worse. That's why you don't see too many uses of high-performance composites in production cars.

Just imagine if you had to produce a composite body part for even a relatively low volume car like a Toyota Prius. That would be something like 100,000 parts in about 9 months, or a part every 4 minutes working 24 hours/day. Not realistic.

[G-Rock]

Never say never riffraff.
Mass producing composites will happen and it may take something like the aircraft industry to do it. Nothing in engineering is impossible as long as there is talent, money and vision to do it.