Alternate aircraft propulsion

B744skipper · Post by **B744skipper** » 24 Mar 2005, 21:32

On another forum someone asked what about alternate aircraft propulsion:

In about 10 to 20 years the oil will start to get scarce. Since there is less oil found and the consumption of oil is increasing in a bigger rate, this will have radical affects on the price. Predictions are that the oil price will rise from $56 to $100-$120 dollars a barrel.

Until there will be nothing left....

Aircraft have an economical lifespan of about 20-30 years. They run on jet-fuel, which is "surprisingly" an oil product. That will lead to the economical life span of aircraft being reduced, or that they will be grounded because of the high fuel costs when no one can afford a ticket any more.

In the car industry you hear continuous news about hybrid cars, or cars running on hydrogen power. But when it comes down to alternate propulsion in the aircraft industry, you never hear a thing.

What's your opinion on this delicate subject, and are there already some aviation related project for alternate propulsion?

Thanks in advance.

B744skipper · Post by **B744skipper** » 25 Mar 2005, 14:18

Has no one any information/opinion regarding this subject?

an-148 · Post by **an-148** » 25 Mar 2005, 14:34

I've seen some years ago photo's of a "cryogenic" plane (looks a little bit like the belouga - because of the tank) I'm not sure the problem of the dangerous fuel - hydrogen - can be solved easily, but like you write: it begins to be time thinking about it !!! We are surely not alone to think about it : what are the projects of plane/engines manufacturers??????/

x-prise · Post by **x-prise** » 25 Mar 2005, 19:58

propfans

anyone one have any idea about how economic propfan aircraft could be in the future cuz russia has had ideas and has made one aircraft that i know of that uses them (An-70 UKRAINE) but would their engines and fuel consumption be more economic and what of their speed?

HorsePower · Post by **HorsePower** » 25 Mar 2005, 21:11

About new energy, I've read recently that some small planes have engine who works with vegetal oil. Not sure but I think it was Argentina.

Regards

Seb.

L-1011 · Post by **L-1011** » 25 Mar 2005, 23:00

Unfortunately, for planes you can't make them fly with electricity, because of the wing-area you'd need, or the batteries which would be too heavy.
The same accounts for hydrogen -> Weight!! (the tank would be too heavy)

For now, I only see hydrocarbon based fueling methods for planes, if you want to keep the same sizes, speeds and ranges. What you can do is take some "human made" hydrocarbon fuel instead of the fossil one. Two advantages arise, the fact that you have a neutral CO2 balance, and the fact that today's technology is compatible.

Let's see what the future will bring

ciao,
TriStar

Alistairbastian · Post by **Alistairbastian** » 26 Mar 2005, 11:25

some info on hydrogen engines

NASA and the Air Force have conducted at least some basic research into hydrogen engines, but very little information is publicly available. However, as a general rule, no engine can function using hydrogen alone. Every form of combustion, from a simple fire to an automobile engine or a jet engine to a rocket, requires two substances to function: a fuel and an oxidizer. In most cases, the oxidizer is air. For example, an automobile engine creates a mixture of gasoline (the fuel) and air (the oxidizer) that is burned to release energy while a jet engine mixes jet fuel and air to produce the same result. A rocket is somewhat different since it carries both the fuel and oxidizer aboard. A liquid rocket typically burns a mixture of liquid hydrogen and liquid oxygen to generate thrust. While many potential mixtures exist for solid rockets, a common propellant is made up of a solidified piece of hydrocarbon with small chunks of oxidizing salts mixed in. Once ignited, the hydrogen and oxygen are released from their chemical bonds, mix, and are burned to produce energy.

So in answer to your original question, a hydrogen engine does not use only hydrogen. The hydrogen is only the fuel, and it requires some form of oxidizer to undergo combustion. Depending on the application, the hydrogen may be mixed with air and combusted similarly to a jet engine, or the hydrogen could be carried in liquid form and mixed with liquid oxygen that would also be carried aboard the vehicle.

the source

http://www.aerospaceweb.org/question/pr ... 0047.shtml

Alistairbastian · Post by **Alistairbastian** » 26 Mar 2005, 11:52

Hydrogen gives a minimum pollution of the environment

. The high heat of hydrogen combustion exceeds heat of kerosene one in 2,8 times; high completeness of hydrogen combustion allows to increase engine efficiency, to reduce specific fuel consumption, to reduce weight and overall engine dimensions. :thumbsup2:

The problem is the density. Liquid hydrogen and oxygen are not very dense and as a reasult, require large fuel tanks. As first proposed, the SR-71 was going to be hydrogen fueled...and 300 feet long.

Liquid hydrogen would require a cryogenic system and size could be large since the density is low and in case of leak a bigger "boom"

mrocktor · Post by **mrocktor** » 01 Apr 2005, 21:34

Hydrogen's energy/weight ratio is terrible, even without considering the weight of the necessary containment means.

Until fusion is viable we will not see hydrogen powered commercial aircraft.

One alternative is bio-fuels, their energy/weight ratio is worse then current aviation fuel, but not by the gross margin that hydrogen is.

One pioneering (and commercially viable!) initiative:

"10/10/2002
EMBRAER DEBUTS ALCOHOL-POWERED VERSION OF ITS IPANEMA CROP-DUSTER

Indústria Aeronáutica Neiva, a wholly-owned subsidiary of Embraer, presented today a version of its crop-duster aircraft EMB 202 Ipanema equipped with an engine powered by alcohol. The objective of the Company is to give a boost to agricultural aviation, as studies indicate a new cost/benefit ratio in items such as operational cost, potency and consumption with alcohol-powered aircraft.
The project is being developed in partnership with CTA (Centro Tecnológico Aeroespacial, the Brazilian certification authority based in São José dos Campos, SP) and has the technical support of both Lycoming and Hartzell, manufacturers of the engine and propeller group, respectively.

“Confirming the market acceptance and the validity of the concept, we expect to obtain certification for both aircraft and engine in 18 months,” said Neiva’s CEO Paulo Urbanavicius.

Neiva believes alcohol to be a viable option to the crop-duster market because the fuel is environmentally friendly and research data indicates it can extend the engine maintenance cycle, making it even more promising. The Ipanema crop-duster is a sales leader, with 30 years of uninterrupted production and 850 units marketed in the period. This represents 85% of the national fleet in this segment, which today counts some 1,000 units.

The model to be fitted out with the alcohol-powered engine is the latest of that renowned aircraft family, the EMB 202 'Ipanemão.' It yields 300 horsepower and its hopper capacity is 40 percent superior to its predecessor’s, carrying 950 liters (250 gal) or 750 kg (1,650 lbs) of chemicals. Aerodynamic enhancements such as winglets and a new wing profile have improved performance of the aircraft, making it faster and more productive. "

mrocktor

HorsePower · Post by **HorsePower** » 01 Apr 2005, 21:52

Ipanema indeed, that's the plane I was talking about. So it is Brazil, not Argentina, sorry. Note that all Ipanema are not alcohol-powered but all of them can be converted quite easily.

Regards

Seb.

earthman · Post by **earthman** » 02 Apr 2005, 23:00

Actually, hydrogen's energy/weight ratio is three times better than regular jet fuel. The problem is that even when it's liquid, it has a very low density, thus requiring lots and lots of space to store it. Imagine an A380 with the whole upper deck used for fuel storage..