Renewable (Alcohol) Fuel Based Aircraft Jet Engine

The most direct conversion would seem to be biodiesel-like oils (e.g., camelina). They have some of the same characteristics as jet fuel, and there is some experience in using camelina jets. Hydrogen is impractical even in land vehicles, and the hurdles to overcome for air use would be daunting. Hydrogen is also expensive to produce.

Alcohol (especially butanol) sounds like a good bet as well. Energy density by both weight and volume are issues in aircraft, and butanol is good in both respects.

This Wikipedia article provides a summary of aviation biofuel development. It looks like the trend might be toward plant oils.

well, ethanol can be made from organics and will serve as a jet fuel. It has less energy per mole, as it has some oxygen already.

Butanol can be made from oil = self defeating for the purpose. They might be able to find a bio route to butanol, but it will be less efficient as it will pass through the ethanol stage and 2 carbons added, with the ethanol stages suppressed.

So it looks like ethanol is the one. This is good, biomass to ethanol to CO2 + water to biomass...

High performance jets played with the boranes, in the 60's and 70's but they turned out to be very costly and never used in volume.

Butanol can be made from oil = self defeating for the purpose.

But it can also be made from biomass, using the same feedstocks as ethanol, but it has substantially higher energy density then ethanol, making it a a better fit for retaining useful aircraft range.

Yes, butanol is indeed viable as a fuel, via the A.B.E. process.

All we need to do is wait for the price of oil to get high enough to drive it. Sadly, it looks as if China and India via coal are going to be the drivers of CO2 in the air. Once China/India see the light, will they act to limit CO2 production? This will emerge over the next 100 years as the US$ declines to the point that the USA can make things domestically again

Alcohol would be very low on my list of candidates to replace kerosene, or any aviation fuel. The efficiency of aircraft is very sensitive to the energy density of their fuels, and alcohol has a lower energy density than any current aviation fuel.

Another problem with alcohol is high vapor pressure compared to kerosene, which means that major changes will have to be made to the entire fuel system architecture, adding weight and further penalizing efficiency.

Biodiesel carries a lower energy-density penalty, and has a low vapor pressure, so it would be my choice for a direct replacement requiring no or mininal fuel system changes. Assuming, of course, that enough can be produced to make it logistically viable.

One among the winners of the 2010 AHS design competition was a tiltrotor vtol concept named 'Silver' by Nishant S.P. (pdf available for download.) http://www.vtol.org/awards/sdcomp.html The hydrogen fuelled concept shows a process to produce hydrogen at the site of combustion. This should be of interest to you. Regards.

Um...what piolenk said.

Its not just weight sensitivity...alcohol will severely affect the range. However there is one other thing...aircraft are amazingly long lived. Any plane coming off the assembly line today will likely be flying fifty years from now. The conversion of fuel from one type to another will take a correspondingly long time. Rushing it would be really really uneconomical and so the conversion would be resisted.

Of course, it may be forced upon us...as peak oil becomes a reality.

The problem of fuel for aircraft will be solved instantly when we figure out how to power airplanes with their own paperwork.

Hmmm... I may be on to something.

The US Air Force is seeking a way to crack CO2 to synthesize JP-8, the currently specified fuel for jets. See http://www.dodsbir.net/sitis/display_topic.asp?Bookmark=39779 Sandia is investigating using solar energy to crack CO2 for fuel. See https://share.sandia.gov/news/resources/news_releases/alliance-formed-to-commercialize-technologies-that-convert-waste-co2-into-diesel-fuel-using-solar-energy/

Solar or other non-fossil-fuel energy sources will have to provide the energy for electrolytic or thermal dissociation of CO2, because using fossil fuels for the cracking energy would produce more CO2 than is cracked. This is a real job for wind and solar, something they can do better than fossil fuels. They can't possibly compete with fossil fuels for the job of baseload power because they are intermittent and can't be connected to the grid. Renewable energy standards (quotas) can't overrule reality.

CO2 could be pipelined to wind and solar sites for cracking, which could be done whenever the energy is available, giving valuable oxygen (for oxygen-blown gasification or oxyfuel combustion) and elemental carbon, or, in simultaneous electrolysis with water, syngas for synthesis of synfuel by the well-known Fischer-Tropsch method that kept the panzers rolling in WWII. See Radial Counterflow Shear Electrolysis http://www.freepatentsonline.com/y2009/0200176.html and Hybrid Power http://www.freepatentsonline.com/y2010/0146927.html

oooooooo did i rember in the early eighties a news item on the russians, err airo-flop err .mucking about with chicken .ummm waist ????. im shure they were actualy flying .theyhad to have extra fuel tanks where the hand luggage goes.hmm darnit im gonna have to google that now