Avijacija bez granica...

[hazard]

Ma znam za vodonične, nisam se precizno izrazio, mislio sam više na ove koji gutaju gorivo na sobnoj temperaturi. Čitao sam davno jedan članak o tome šta sve šatl ispušta u atmosferu prilikom samo jednog lansiranja pa nisam sklon vodoniku/prirodnom gasu. Ovo sa algama deluje interesantno. 

 

http://www.biofuelstp.eu/spm6/docs/dominik-behrendt.pdf

 

http://www.oilgae.com/

 

http://energy.gov/eere/bioenergy/algal-biofuels

 

itd.

 

Problem je, kao i uvek, "skaliranje", tj. masovna (ali bas bas masovna) proizvodnja. Kada bi drumski transport prebacili uglavnom na elektricna vozila, mozda bi mogli da uzjagamo dovoljno biogoriva (na razne nacine - alge su najefikasnije po pitanju povrsine koje zauzimaju) za potrebe aviotransporta.

[namenski]

Radoye :D  (i ostali zainteresovani, naravno) sta je ovo?

 

[wall]

Parojaroplan?

[Radoye]

Radoye :D  (i ostali zainteresovani, naravno) sta je ovo?

 

ppa.jpg

 

Parojaroplan?

 

Dasta nego parojeroplan! :D

 

http://www.youtube.com/watch?v=nw6NFmcnW-8

[namenski]

Parojaroplan?

Svaka cast i cest obojici!!! :)

[bigvlada]

Sta si navalio na satl, isto i jos vise od toga ispustaju i razni Protoni, neutroni, Energije i ostali, obaska sto raketni motor em ne spada u motore sa unutrasnjim sagorevanjem (oko njih si se zapitao) i obaska sto rakete nisu visoko na listi zagadjivaca: glavni vazdusni zagadjivaci su avioni kakve danas znamo i tu ce, bez obzira na vrstu goriva, jos dugo da vazi tehnoloski aksiom da 'ni kod babe nema dzabe'

Gasna turbina je ubica #1, pomorske i kopnene varijante istih vec uspesno prelaza na gas/dual fuel, vazdusne jebe skladistenje gasa odnosno tezina tankova, tako da je za sada uglavnom sve moda i sminka za umiriti savest i ekoloski svesne.

 

Pa za šatl sam čitao,  za ostale nisam, :) sem što znam da kada se koriste hipergolična goriva mora da se dekontaminira teren nakon lansiranja. Slažem se sa napisanim. 

 

http://www.biofuelstp.eu/spm6/docs/dominik-behrendt.pdf

 

http://www.oilgae.com/

 

http://energy.gov/eere/bioenergy/algal-biofuels

 

itd.

 

Problem je, kao i uvek, "skaliranje", tj. masovna (ali bas bas masovna) proizvodnja. Kada bi drumski transport prebacili uglavnom na elektricna vozila, mozda bi mogli da uzjagamo dovoljno biogoriva (na razne nacine - alge su najefikasnije po pitanju povrsine koje zauzimaju) za potrebe aviotransporta.

 

Hvala, probrstiću ovo. Ako drumski saobraćaj bude na električni pogon, vrlo je verovatno da će takav biti i avio saobraćaj. Ionako je cesna testirala električnu verziju 172-ke pre par godina. 

[hazard]

Ako drumski saobraćaj bude na električni pogon, vrlo je verovatno da će takav biti i avio saobraćaj. 

 

Sumnjam, osim ako ne bude neka fuel cell varijanta kao u clanku koji sam linkovao pre koju stranu. Jednostavno, jedno je brinuti o tezini baterija kada ih "vuces" po zemlji (automobil, bus) a drugo je kada treba da ih vines u vazduh. Takodje, autobus koji putuje od recimo Njujorka do Los Andjelesa moze da stane X puta da puni baterije (a voz moze da pici bez stajanja za punjenje jer nema baterije vec se napaja "odozgo"), a avion na toj trasi treba da leti nonstop (o duzim prekookeanskim trasama i da ne pricamo). Laki avioni mozda predju na baterije, za putnicke sumnjam, bio bi potreban neki ludacki breakthrough na polju baterijske tehnologije. To je naravno moguce ali ne skoro (u sledecih recimo 30 godina, verovatno).

 

Nama za pocetak treba proboj na polju baterija koji ce omoguciti:

 

1) Da prosecan auto moze da ide 500-600 km na jednom punjenju u prosecnom profilu voznje

2) Da baterija koja to omogucava ne kosta boga oca (da bude pogodna za masovnu proizvodnju i da ne zavisi od nekih egzoticnih materijala koje je tesko nabaviti)

3) Da baterija koja ispunjava prethodna dva kriterijuma ima neki prihvatljiv vek trajanja, npr. 10 godina pre nego sto mora da se menja (ako razmislis, shvatices da akumulator u kolima menjas cesce, npr. svake 3 do svakih 5 godina, recimo)

4) Da takva baterija moze uspesno da se reciklira.

 

Priblizavamo se ovom idealu, ali ima jos da se ide. Mislim da je stavka 2) (cena) najteza da se ispuni.

 

Postoji jedna moguca avenija napretka, a to litijum-vazdusne baterije (umesto litijum-jonskih):

 

http://spectrum.ieee.org/energywise/transportation/advanced-cars/big-leap-in-lithium-air-battery-tech

 

 

Leap in Lithium-Air Battery Tech Could Supercharge Electric Cars

 

By Charles Q. Choi

Posted 29 Oct 2015 | 18:00 GMT

 

Lithium-air batteries can in principle hold five to 10 times as much energy as a lithium-ion battery of the same weight and double the amount for the same volume. They could theoretically give electric cars the same range as gasoline ones. Now scientists in England claim to have overcome many of the current barriers preventing their use.

 

In a lithium-air battery, the anode is generally made of lithium metal, the cathode is typically a porous carbon material that brings in oxygen from the surrounding air, and the electrolyte is a liquid connecting the anode and the cathode, helping ions shuffle between them. As the lithium oxidizes, it discharges electricity. Recharging the device reverses the process.

 

A number of major pitfalls have kept lithium-air batteries from meeting their full potential. For instance, when they discharge electricity, lithium peroxide particles usually form that can clog the porous cathodes, stifling the batteries. In addition, unwanted chemical reactions can attack the electrolytes, reducing the battery's overall efficiency. Moreover, these devices are very sensitive to moisture in the air, which can corrode the lithium metal anode.

 

To overcome these problems, scientists at the University of Cambridge designed their battery to produce lithium hydroxide crystals instead of lithium peroxide particles, and added lithium iodide as a mediator compound. These changes greatly reduced unwanted chemical reactions that can damage the electrolytes of lithium-air batteries and kill the devices.

 

Moreover, the researchers used macroporous reduced graphene oxide for their cathode instead of the mesoporous carbon typically used in other lithium-air battery cathodes. This thousand-fold increase in pore size — from pores 10 to 100 nanometers wide to ones 10 to 100 micrometers wide — helped prevent the lithium hydroxide crystals that formed during battery operations from clogging the pores. The scientists introduced the solvent dimethoxyethane to help remove these crystals as the battery charged and discharged.

 

Furthermore, this new design showed a high tolerance for water, suggesting it could tolerate moisture in the air. "This finding of water tolerance is another step forward towards a practical lithium-air battery," says study lead author Tao Liu at the University of Cambridge.

 

Future research can explore bringing more oxygen into the device, says study co-author Clare Grey, also of the University of Cambridge. The researchers need to find a way to keep the lithium metal from forming spindly fibers known as dendrites, which can cause batteries to short-circuit and explode, Liu says. Moreover, while this battery can tolerate water, the researchers also have to figure out how to protect it from carbon dioxide and nitrogen, which can also corrode the lithium metal, Liu adds.

 

The scientists detailed their findings in the Oct. 30 issue of the journal Science. The researchers have patented their work, and the intellectual property is owned by Cambridge Enterprises.

 

Ima i ovde jos jedan clanak na tu temu:

http://spectrum.ieee.org/nanoclast/semiconductors/materials/stable-superoxide-could-usher-in-new-class-of-lithiumair-batteries

 

Medjutim ove baterije i dalje koriste litijum, koji je skup (i relativno redak, i nesto tipa pola ako ne vise globalnih rezervi je u Kini). Ono sto je meni privuklo paznju su natrijum-vazdusne baterije (sodium-air). Funkcionisu po istom principu, ali se koristi natrijum umesto sodijuma. One imaju dosta manji energetski potencijal od litijum-vazdusnih baterija, ali imaju tu prednost da natrijuma ima gde hoces i koliko hoces - dzabe je. Mislim, so nije neki nedostupan resurs :D

 

Ima dugacak clanak o tome ovde (i poredjenje te dve vrste baterija), jako je interesantan:

 

http://spectrum.ieee.org/transportation/advanced-cars/an-electric-car-battery-that-will-get-you-from-paris-to-brussels-and-back

 

Evo odlomka:

 

 

Sodium: Less Energy, More Stability

 

Sodium-air batteries are another interesting possibility, despite having an energy density lower than that of the lithium-air chemistry.

 

The lower energy reflects the nature of the reaction, which uses only one electron and thus generates a superoxide (NaO2) instead of sodium peroxide (Na2O2). This reduces energy density immediately by a factor of two. The reaction’s theoretical specific energy is approximately 1,100 watt-hours per kilogram.

 

On the other hand, sodium-air batteries charge up more efficiently than lithium-air batteries because they have a very low overpotential—less than 20 millivolts as opposed to 700 mV. As a result, it’s possible to keep the operating voltage under 3 volts, which protects components from destructive oxidation, notably the electrolyte destruction observed in the lithium-air system. We have proved this by measuring efficiencies above 98 percent. These results make for good stability during cycling: After 50 cycles, the cell’s capacity is essentially unchanged.

 

There are a few technical challenges to overcome. For instance, because of the nature of the oxidation, the sodium-air battery sucks in twice as much air as its lithium-air equivalent, requiring an airflow comparable to that of a piston engine of the same power. Then there’s the high chemical reactivity of sodium metal, which you may remember seeing demonstrated in high school, in which a small piece of sodium reacts violently with water.

 

Lithium is comparatively rare, and it isn’t cheap. But sodium is as common as table salt, and it’s not expensive. The materials of a sodium-air cell would likely cost less than a tenth as much as those in a lithium-ion battery. In the long run, lithium-metal batteries promise the best performance, but given the combination of stability, low cost, and still-impressive specific energy, the sodium-air technology might serve to bridge the gap between today’s batteries and those of the more distant future.—W.W.W. & H.-C. Kim

 

E sad, cak i da se sve to obistini, ja opet mislim da nije dovoljno za avijaciju, bar onu dugolinijsku. Ono sto jeste interesantno je da ove metal-vazdusne baterije usisavaju vazduh da bi se praznile, slicno kao sto avionski motori usisavaju vazduh da bi ga koristili u reakciji sa gorivom.

[namenski]

 

Pipistrel d.o.o. i Sino GA Group potpisali su ugovor vredan cirka 500 miliona evra koji ce, kako kazu, da se pozabavi proizvodnjom oko 500 komada aviona godisnje.

U Kini.

Projekat u trajanju od 7 godina predvidja izgradnju skroz nove fabrike, poletno-sletne staze, pogona za odrzavanje i obuku, transfer tehnologije obaska.

Ali: u novom pogonu proizvodice se Pipistrel elektro modeli Alpha Electro i Panthera Hybrid.

Ali, ali: deo para Pipistrel se obavezao da utrosi na razvoj novog zero-fuel emission malog putnickog aviona sa 19 sedista u kome ce, pored hibridnog pogona, biti koriscene i niskotemperaturne vodonicne gorivne celije.

Edited December 2, 2016 by namenski

[namenski]

DLR Pipistrel HY4

 

 

 

Pipistrel d.o.o, Tine Tomazic i 1 Nemac, ko bi drugi, Joseph Kallo, DLR, Deutsches Zentrum für Luft-und Raumfahrt, 2 Pipistrel Taurus G4 = Pipistrel HY4.

Posle 2011. i pobede na svetskom NASA-CAFE Green Flight Challenge, sa sve nagradom od 1,350,000 US$: vodonik, elektrika, i - prelet od 320 km prosecnom brzinom od 180 km/h uz utrosak energetskog ekvivalenta 2.17 litara avionskog benzina...

 

Sve tehnicke i ekonomske pojedinosti na stranu, tek, a u vezi s gore pomenutim kinesko-slovenackim malim putnickim avionom, Kallo kaze:

With our present technology we now know how to produce up to one megawatt, which means we could power a smal l 19-seat regional airliner over distances of 1,000km at 400kph. That would require 420 grams of hydrogen per passenger. We are already working on the project.

[namenski]

????

 

 

 

Detalji za od eventualne pomoci:

 

 

[vathra]

Шта се чудиш? Никад ниси видео Апача?

[namenski]

Koji si ti serator jebote  :D

 

Znak pitanja (?) znaci pitanje.

Za znak cudjenja jos nisam cuo.

Dok ga ti nisi izmislio 

 

Dakle, znas ili ne znas?

[Radoye]

Pa rek'o je, Apac...

[namenski]

Jes vala, sta se i ja bunim, dobro da me nije oterao u pizdu materinu... :)

[namenski]

Godisnji popis:

 

Svet, vojno, ukupno:

 

1.  USA, 13,764 ili 26%
2.  Russia, 3,792 ili 7%
3.  China, 2,955 ili 6%
4,  India, 2,104 ili 4%
5.  Japan, 1,594 ili 3%
6.  South Korea, 1,477 ili 3%
7.  France, 1,305 ili 2%
8.  Egypt, 1,137 ili 2%
9.  Turkey, 1,018 ili 2%
10. Pakistan, 951 ili 2%

 

Ostali: 22,945 ili 43%
Ukupno, komada: 53,042 

 

 

Od toga takozvani borbeni:

 

1. F-16, 2,312, 16%
2. F-18, 1,071, 7%
3. Su-27/30, 940, 6%
4. F-15, 874, 6%
5. MiG-29, 829, 6%
6. MiG-21, 547, 4%
7. Su-25, 511, 3%
8. F-7, 450, 3%
9. J-7, 418, 3%
10. F-5, 416, 3%

 

Ostali: 6,271, 43%
Ukupno 14,639 

Edited December 8, 2016 by namenski