Fuel saving ideas?

Flybe · Post by **Flybe** » 19 Jul 2007, 22:10

In this era, the most important thing for airlines is to reduce the amount of fuel used by their planes, as it is one of the most expensive things around these days.

On top of that, saving fuel is also a good ecologist strategy, which makes it important in the eyes of the general public. And less fuel means less possibility to blow up, in case of an accident.

Engines save more and mor fuel, but how to change it more radically? Any ideas are welcome.

The following is an idea I had today, maybe already adopted in one or the other way. I would be happy to hear your reactions, especially of technicians, on what would be the problems, and if it is even possible.

Planes have engines, turbines with fans, that power them. They are powered by energy that comes from fuel.

Where else do we see the use of fans? On land, big fans are used in windmills to power a kind of dynamo, that generates electricity. The require a minimum of wind to generate electricity, so they cannot always do that.

But, put those extra (smaller of course) fans on a Turboprop. Yes, a turboprop with 4 engines with fans, 2 to power the aircraft, 2 to produce energy. In a later stage maybe even try to build the 2 things into 1 engine. Because that is one thing that an aircraft never lacks when it is flying... wind.

Sure, you still need fuel engines for take of and landings, and even during flight (because the power generated from the fans wont be enough to power the other fans to maintain the speed), but during flight, wouldn't there be a substantial saving on power.Put in a strong battery and you might even have extra energy available during take-off, powered by the former flight.

Now, I'm no technician, and for sure I'm forgetting about a few things, but would this idea be viable, and would it be possible to generate enough savings during flight to allow for the extra weight, etc? I guess for jets, a similar system could be developed, no?

And why not high-speed trains, cars (hybrid, battery under a certain speed, normal engine between minimum and maximum speed, engine + fans above certain speed.

Isn't this using windenergy at it's best performance? Such a powersupply can start from the moment the critical speed is crossed, and every extra power it gives, requires less power from another (fuel-using) powerunit.

So, I would like to have your ideas on this (just don't develop this idea without my knowledge and then earn much money on it 8) ), and of course, other ideas are also welcome! Think radical, there are many ways to create energy, and the energy generated from burning fuel is just one of the many ways!

Greets,

Pieter

PS: Moderators, as there isn't a real technical forum on here, this is posted in the Civil Aviation forum. Feel free to move it to another forum (as long as it isn't the Luchtzak Pub, because I'm serious on this topic) if wished.

Cartman · Post by **Cartman** » 19 Jul 2007, 22:52

Wouldn't it affect the aerodynamic features of the aircraft of train?

And I believe that there is a law in physics that states that this would only be possible in a prefect isolated system with no energy loss. I think that the amount of energy produced by the 'generator' can never be enough to keep the same machine in motion (but I'm no technician).

But hey, if this would work, you would have invented the famous 'perpetuum mobile' that scientist have been looking for since ages

Flybe · Post by **Flybe** » 19 Jul 2007, 23:27

And I believe that there is a law in physics that states that this would only be possible in a prefect isolated system with no energy loss. I think that the amount of energy produced by the 'generator' can never be enough to keep the same machine in motion (but I'm no technician).

True, that's why I said:

Sure, you still need fuel engines for take of and landings, and even during flight (because the power generated from the fans wont be enough to power the other fans to maintain the speed), but during flight, wouldn't there be a substantial saving on power.

But if there is a substantial reduction of fuel-based power during flight, that's already interesting enough too, no?

Aerodynamics would be affected, but no more than by a normal engine. So if the power gained by adding this "windmill" is more than the extra power needed because of the loss of aerodynamics, it is still beneficial. The question is, how many benefits are left after distracting the loss of aerodynamics? Still enough to make it worth the investment?

Edit: probably the loss of aerodynamics follows an exponential curve. Meaning that with the adding of every 1 more "windmill", the loss of aerodynamics grows quicker. So there is an optimum to be found on how many windmills are possible before the loss of aerodynamics offsets the gains of power. Question is here: is this optimum lower or higher than 1 "windmill" placed on the aircraft? 8)

Greets,

Pieter

Gliderpilot · Post by **Gliderpilot** » 19 Jul 2007, 23:48

Flybe wrote:So if the power gained by adding this "windmill" is more than the extra power needed because of the loss of aerodynamics, i is still beneficial.

It's actually the opposite in real life. You'll burn more fuel because you have more drag due to those "windmills".
The energy generated by one windmill will just be enough to compensate the drag generated by the same windmill (in a world with no friction and always the best efficiency). This is called "de wet van behoud van energie" in dutch, or something like "law of conservation of energy" in english (?).
Because the efficiency of all mechanical systems and converters will never be 100% (or become even close to it) you have to produce more energy by the real engines with these windmills on your plane than without these windmills.

I hope you'll understand.
(it's already late and my english is not that good...

)

Thomas

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 20 Jul 2007, 00:53

This is an idea I had too

But it is not a new idea as RAT's (Ram Air Turbines) use this principle to keep hydraulical power in the event of a power off.
Read this page about the Gimli glider: http://www.casa.gov.au/fsa/2003/jul/22-27.pdf

The rotating turbine could not even provide enough energy to power the flaps nor the speedbrakes nor the landing gears.

A windmilling turbines creates enormous drag at high speeds which has to be compensated by a higher fuel burn. It still might generate a slight profit in electricity if engines are economic.
Where it starts to break down is when you add a battery that has a certain dimension and weight (too small is not interesting), which will reduce available space and increase aerodynamical drag because of its weight that needs to be compensated.

What remains is a slight profit in electricity.

If you take into account the cost of installing and maintaining such a system, the risk of carrying it all the time and the cost of ground installations it seems that it would not be very interesting.

I guess the best thing now is to invest in research for alternative energies. A great example is hydrogen-powered hybrides. Delijn is the first to experience it on busses and it seems to work althoug consumption is still quite high. I m sure this technique will be improved over the years.

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 20 Jul 2007, 01:00

It's actually the opposite in real life. You'll burn more fuel because you have more drag due to those "windmills".
The energy generated by one windmill will just be enough to compensate the drag generated by the same windmill (in a world with no friction and always the best efficiency). This is called "de wet van behoud van energie" in dutch, or something like "law of conservation of energy" in english (?).
Because the efficiency of all mechanical systems and converters will never be 100% (or become even close to it) you have to produce more energy by the real engines with these windmills on your plane than without these windmills.

I think that Flybe 's idea is not to recycle 100% of the energy but even a slight part of it and to bring it together from many planes and many flights.

Desert Rat · Post by **Desert Rat** » 20 Jul 2007, 09:26

To give the ETOPS option free of charge for the Airlines and all the performance related mods as well,like increase in MTOW,MLW,MZFW,15 Knts tailwind,Flex TO to 40%, etc.....

Indeed all these options are chargeable by the different manufacturers,and most of time are just administrative mods(no real modification of the A/C's) but have a real impact on fuel consumption....

earthman · Post by **earthman** » 20 Jul 2007, 09:43

All the 'wind' on a plane is only there because it's engines are pushing it through the air. Wind energy on the ground is generated by the fact that the windmill is attached to a different medium (the ground) than the moving mass of air.

Let's just say it won't ever work in our universe.

On the other hand, it might be an idea to implement regenerative braking on planes, both on the wheels and especially instead of the usual means of slowing down on final approach, which only generates noise and heat.

Post by **sn26567** » 20 Jul 2007, 10:05

Flybe wrote:PS: Moderators, as there isn't a real technical forum on here, this is posted in the Civil Aviation forum. Feel free to move it to another forum (as long as it isn't the Luchtzak Pub, because I'm serious on this topic) if wished.

Flybe, you could not have chosen a better forum to post this interesting topic.

an-148 · Post by **an-148** » 20 Jul 2007, 11:11

let's say so:

the above mentionned proposal is equivalent to this one:

- let's put on the same table an electrical ventilator and a windmill coupled to a generator, facing each other.

You put on the ventilator and use energy to do so, let's say 100%, the blown air is propelling the facing windmill, that drives the generator. You will effectively have an energy output at the generator. BUT, please tell me the benefit of using 100% energy to produce, maybe 40% in the best conditions.

In other words: to make a plane mobile, you need energy; to afford more drag because of an obstruction in the airflow, called drag, you need more energy: what is the benefit of the whole thing ?????????????,

Totally different would be to think about a way to loose as much as possible energy, when descending from cruise FL to full stop, i.o.w.: change the cinetical energy in potential energy. We see very often planes using their airbrakes to have a better descent rate without gaining too much speed, a.s.o.: there (and only there, I see a way to use the power of airflow, that's indeed very minimal)

FLY4HOURS.BE · Post by **FLY4HOURS.BE** » 20 Jul 2007, 14:26

change the cinetical energy in potential energy

I think it's the other way around if you're in a descent

teddybAIR · Post by **teddybAIR** » 23 Jul 2007, 10:22

I think I found an effective way to reduce carbon dioxide emitions...yet, I already know it is not the most popular way to do so...nevertheless, I am convinced it is one of the most efficient measures that can be taken: make it more expensive to burn fuel (ie: more taxes on fuel).

Airlines (including LCC's) would have to charge these surplus costs to customers, thus making air travel a less interesting option. IMHO this could have a great impact. The profit from the taxes can be invested in aviation related green projects in order to ofset the margin loss for the airlines (ex: subsidise a program that makes the use of public transport to the airport for all employees free, invest in photovoltaic panels and thus lowering the energy bill for airlines, make it fiscally interesting to buy planes which have a low emission rate,...)

Conclusion: Provided that the income from the levied tax flows back to the aviation industry, I think it would be possible to lower emissions without affecting the industry's competitiveness thanks to 2 effects: less passengers and lower energy consumption.

Best regards,
Tom[/u]

earthman · Post by **earthman** » 23 Jul 2007, 11:01

teddybAIR wrote:I think I found an effective way to reduce carbon dioxide emitions...yet, I already know it is not the most popular way to do so...nevertheless, I am convinced it is one of the most efficient measures that can be taken: make it more expensive to burn fuel (ie: more taxes on fuel).

Airlines (including LCC's) would have to charge these surplus costs to customers, thus making air travel a less interesting option. IMHO this could have a great impact. The profit from the taxes can be invested in aviation related green projects in order to ofset the margin loss for the airlines (ex: subsidise a program that makes the use of public transport to the airport for all employees free, invest in photovoltaic panels and thus lowering the energy bill for airlines, make it fiscally interesting to buy planes which have a low emission rate,...)

Conclusion: Provided that the income from the levied tax flows back to the aviation industry, I think it would be possible to lower emissions without affecting the industry's competitiveness thanks to 2 effects: less passengers and lower energy consumption.

Best regards,
Tom[/u]

Yes and such measures worked wonders for automobile use, didn't they? The higher price of a plane ticket will then have to be compensated by using more energy elsewhere while earning the extra money needed for the ticket. Solving technological problems using taxation is a ridiculous idea.

.

teddybAIR · Post by **teddybAIR** » 23 Jul 2007, 11:06

earthman wrote:
Solving technological problems using taxation is a ridiculous idea.

Uhuh, I can see your point, yet I would have expected a more constructive reply...nevermind!

Post by **Bruspotter** » 23 Jul 2007, 12:03

Hello

I think Boeing just did big steps in saving fuel if it comes to the construction itself.

-It's aerodynamic (look at the shape of the nose)
-It consist almost totally out of lightweight composites
-these composites are very strong and yet much lighter than metal + they are hard and smooth...in fact they wouldn't need a that thick paint layer...a good toplayer would be satisfactory. (so if you use less paint, you spend less money and you save weight = double effective).
-it has remarkebly less problems with drag and especially at the wings...look at the raked wingtips.
-the tail has a bit a special design also to push the max. performance with min. drag out of the airplane.
-and you can certainly find many more when just looking at the plane...

Those designs are already a good step forward to the future in the battle to save more fuel. Because right now whe are not yet so far to apply radical techniques in powerig aircraft but the near future will definetly bring new solutions.

Best regards: Yannick

teddybAIR · Post by **teddybAIR** » 23 Jul 2007, 12:07

I agree for the full 100% Bruspotter!

I have one additional question to this thread:

How can we extend this initiative to the entire aviation industry? I ask the question because I believe we shouldn't merely think about the flights. There's a lot more to aviation: the construction of airplanes, airports, the service suppliers at the airport, passengers, comptetition,...

earthman · Post by **earthman** » 23 Jul 2007, 14:54

teddybAIR wrote:
earthman wrote:
Solving technological problems using taxation is a ridiculous idea.

Uhuh, I can see your point, yet I would have expected a more constructive reply...nevermind!

Actually I wanted to suggest developing cleaner planes and cleaner burning aircraft fuel, and making them (or at least the fuel) mandatory for entering our airspace, but I didn't have time to finish that part of my reply.

The problem with artificially making things more expensive is that it also increases the incentive to circumvent the extra costs. You may even discover some airlines using something extremely toxic but very cheap as an alternative fuel, just to save costs.

Avro · Post by **Avro** » 23 Jul 2007, 18:09

Pieter,

It's a nice and interesting topic you have started.

Concerning your idea, and as many other said, it won't be a feasible solution unfortunately.

It's not that easy to find a revolutionary concept to power the airplanes. All the large engine manufacturers including PW, RR and GE are doing some reaserch in order to develop new techniques for the future. The followig list are real projects which are being studied by the different manufacturers.

Post combustion engines

Ionizing air in the combustion chamber

Full electric engines

Cryogenic planbes (the least feasible and economic solution)

Let's try to think out of the box and who knows, we might find a new idea

Chris

Flybe · Post by **Flybe** » 23 Jul 2007, 21:38

Concerning your idea, and as many other said, it won't be a feasible solution unfortunately.

I agree, there are a few things I forgot to take into account.

But there are indeed many possibilities. And thinking out of the box is the best one can do.

Everything is energy, in a larger or lesser extend. The question is how to convert it to energy where we can do something with it (e.g. electricity of directly into cinetical energy for the engines), and this is sufficient extend.

The idea is the following: only a small fraction of the energy produced by the engines goes to the eventual goal of the engines: produce cinetical energy for the fans to move, which in turn moves the plane (or should I say the air around the plane).

Much gets lost in a diversity of "unwanted" energy: warmth, friction, etc. and energy that is used for powering systems like cabinlighting etc.

You can do 2 things with that loss of energy:

* Or you try to reduce the loss of energy wherever possible (e.g. better aerodynamics that saves friction, engines that produce less heat and more cinetical energy, etc.)

* Or - if the former is not possible (immediately) - try to reuse that "lost" energy. Wind energy is indeed a bad example, as it will create an extra drag - or if you you use the blades in a normal engine for powering the elektromotor, you need more energy to power the blades in the first place anyway. But, why not try to reuse the warmth, even the lighting inside (photovoltaic cells anyone?), etc?

And in a third step: anything can create energy (correction - everything IS energy), so why not try to find something that does not involve the normal type of combustion engine. There are more than enough chemical components that give energy when joined together or seperated by a chemical reaction. This chemical reaction does not always need to be explosive or dangerous (by radiation or whatever). Why it isn't used yet? Because it isn't simple. But not simple doesn't mean impossible. Far from. Everything is "simple" once a working method is established.

So let ideas come! There are no crazy ideas. And who knows, maybe Luchtzak might once become famous for being a "energy-think tank".

As far as expanding this to everything in aviation: airports, etc. Indeed, the possibilities are there! Just think of the A terminal in BRU surfaced (the roof I mean) with solar panels... And why not inside the terminal either? The lights are always on anyway...

Ideas are welcome! Somebody needs to be the first with a groundbreaking idea! And statistically, the chances of that somebody being a person in those workinggroups at the airlines are quite slim. (Ours are even slimmer, but sssstttt).

greets,

Pieter

Post by **ElcoB** » 23 Jul 2007, 22:00

Well; have a look at this;:arrow: Fuel-less Gravity Powered Flight

The idea that an airplane can fly endlessly carrying heavy loads of passengers and cargo without burning any fuel, can stop and hover in place weightless at any time, and can takeoff and land vertically is a radical departure from accepted thought concerning aviation. This new reality that is made possible by the invention of Robert Hunt's astounding new hybrid aircraft is Hunt Aviation’s vision of the future of aviation. Our aircraft is a rigid glider made of lightweight composite materials

Aviation24.be

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