FL370
Topic Author
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Is A Hybrid Plane Possible

Mon Sep 25, 2006 5:35 am

would it be possible for a plane to run on half gas and electric? like those new cars that are coming out, like the toyota prius! if would be kind of neat to see a plane to take off using gas and than be battery powered at crusing altitude.
has any plane company tested this possibility?





fl370
 
sccutler
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 5:45 am

The fundamental difference between cars and aircraft makes this improbable in any scenario using curent and reasonably-anticipated technology.

Cars only require a substantial proportion of their available power when they are under acceleration, or climbing significant grade. At cruise, most cars are using something on the order of ten to fiften percent of their available power. Hence, it makes agreat deal of sense to use the hybrids, with which you can boost the available power (briefly) with electric motors, and maintain speed with a smaller-than-traditional gasoline or diesel powerplant.

Aircraft, on the other hand, require a very large proportion of available power to maintain flight. By way of example, when I cruised today from south Texas to Dallas, in a Beech Bonanza, I cruised at about 75% power.

Again, using current tech, there is no scenario where stored electric power could be used for a meaningful amount of propulsion for an aircraft.
...three miles from BRONS, clear for the ILS one five approach...
 
SJCRRPAX
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 5:53 am

Actually, they have pilotless droves now that are hybrid. The reason for them is they cut the gas engine out to run in a "silent mode", kind of like the way submarines work.
 
BDL2DCA
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 5:55 am

Quoting SCCutler (Reply 1):
Aircraft, on the other hand, require a very large proportion of available power to maintain flight. By way of example, when I cruised today from south Texas to Dallas, in a Beech Bonanza, I cruised at about 75% power.

Not to mention that the power to the electric motor is generated via friction as you break. So it is the speeding up and slowing down that generates the power for the batteries.

Hybrids actually work exactly opposite of how you described it:

Quoting SCCutler (Reply 1):
Hence, it makes agreat deal of sense to use the hybrids, with which you can boost the available power (briefly) with electric motors, and maintain speed with a smaller-than-traditional gasoline or diesel powerplant.

Typically, they cruise on the electric motor, and the gas engine is started to provide accelleration.
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supa7E7
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 5:58 am

There has been talk about electrically powered wheels to help taxi around on APU power, without starting the main engines.

However, it seems this would only save fuel during long taxis / ground delays. Otherwise the engines need some warmup time regardless.
"Who's to say spaceships aren't fine art?" - Phil Lesh
 
xxzz123
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 6:23 am

To achieve takeoff power form any type of hybrid would be virtually impossible, and I would question whether the additional fuel burn would ever justify this technology. You need to remember the weight consideratons as well - fuel cells are heavy and I doubt that the technology exists today. But who knows what the research establishments are working on - but even that research would be decades away from the public domain.

Bill.
Bilbo
 
xxzz123
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 6:26 am

Sorry - I wandered off there - yes - I would guess that a hybrid is possible - but not in any way practical......

Bill.
Bilbo
 
sk909
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 6:40 am

Well hybrid is not the next step for aviation engines.

There is a global demand to find a non-carbon based fuel. Thereby minimizing the demand for oil. But I think that we have to wait another 20 - 30 years.
Life's for Living!
 
sv2008
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 6:42 am

Quoting BDL2DCA (Reply 3):
Typically, they cruise on the electric motor, and the gas engine is started to provide acceleration.

No, that's not right.

The electric motor is used to boost acceleration. If it cruised on the electric motor the battery would be flat in no time. Even around town the electric motor can only be used on it's own for low speeds.
 
swissy
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 6:48 am

Quoting SK909 (Reply 7):
Well hybrid is not the next step for aviation engines.

Hybrid I do not think so, different "type" of fuel would be my guess like sort of
bio fuel...............

Cheers,
 
sk909
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 6:56 am

Quoting Swissy (Reply 9):
Hybrid I do not think so, different "type" of fuel would be my guess like sort of
bio fuel...............

Hopefully we will see some hydrogen powered engines. Maybe based on the hydrogen pill technology that Denmark is developing... Big grin
Life's for Living!
 
BOE773
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 6:57 am

Project Orion was going to use nuclear propulsion.

http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29
 
swissy
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 7:03 am

Quoting SK909 (Reply 10):
Hopefully we will see some hydrogen powered engines. Maybe based on the hydrogen pill technology that Denmark is developing...

 bigthumbsup 

Quoting BOE773 (Reply 11):
Project Orion was going to use nuclear propulsion.

Sounds scary and somewhat not user friendly.........


Cheers,
 
sccutler
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 7:57 am

Quoting BDL2DCA (Reply 3):
Hybrids actually work exactly opposite of how you described it:...

...Typically, they cruise on the electric motor, and the gas engine is started to provide accelleration.

Actually, no.
...three miles from BRONS, clear for the ILS one five approach...
 
lehpron
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 8:25 am

Quoting FL370 (Thread starter):
would it be possible for a plane to run on half gas and electric? like those new cars that are coming out, like the toyota prius! if would be kind of neat to see a plane to take off using gas and than be battery powered at crusing altitude.
has any plane company tested this possibility?

Not in the sense that you're thinking of. First we need to make up your minds, what type of hybrid shoud we focus on; should we begin with propulsion or fuel based?

We can burn hydrogen or use it for an electric motor via fuel cell generators, yes. A car has contact with the ground, an airplane has to move air to move. Rolls-Royce has made electric motor generators using their Trent series engines, they are mobile (meaning on a truck as emergency generators) and the output is almost completely converted into electricity, i.e. no thrust at all, and is capable for producing 100 million horsepower! A purely-electric 777 would need two of these. Do these type of motors exist in other industries, yes. Could they fit and fly a 777, no. The weight alone would surpass what the wheels could ever take on the ground.

I don't know how difficult it is to separate out hydrogen from JP fuel using an electrolysis, if it is even possible. Then we can try to use a stardard JP fuel in a fuel cell. Or use something like an giant internal APU to use the fuel to produce vast amounts of electricity for motors. Even then maybe, I stress maybe, a plane the size of a small cummuter could be made to fly purely electric, but what is the point? It probably takes more fuel to burn to generate electricity and run a motor than to take the energy straight from the burner's shaft. Having said that, if it is for the environment then we just might.

[Edited 2006-09-25 01:28:54]
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
acidradio
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 3:28 pm

I can see the world of aviation moving towards different power sources in baby steps. For example, a case could be made for using biodiesel, that is, a vegetable oil-based fuel, as a small component of JetA. Since JetA and Diesel have a lot of similar properties, biodiesel (or something similar) could find its way into JetA one day.

Some governments are jumping on the bandwagon of this as a motor fuel for vehicles - for example, Minnesota mandated that all diesel fuel sold must contain 5% biodiesel. But some bugs definately have to be worked out, for example, the fact that many types of biodiesel (you can make the stuff out of just about any kind of fat) have a propensity to gel up at colder temperatures, usually above what a petroleum-based diesel fuel would.

But then again, the whole world of petroleum and energy is changing before our eyes. Now that price points have gone up, there is more financial incentive for oil prospectors to explore "harder to reach" wells, which cost more to drill and find in the first place. That and the science and technology which is used to find oil and gas wells in the first place gets better and better. For example, a friend of mine who is in that business showed me a very detailed diagram of a gas well field that is being drilled. It turns out that the major well in that field which was drilled 20-30 yrs ago, essentially by guess, is 50 ft. away from a huge gas deposit, which was only discovered recently with newer technology. When more oil/gas wells are discovered, it presumable will put more supply on the market, which will bring price points back down. Also, I have been following a new process (thermal depolymerization) with much excitement which will take things like garbage and sewage (basically anything with carbon in it) and convert it to a form of crude oil, a form of synthesized gas (same idea as natural gas) and a nutricious mulch which is essentially compost and can be used as agricultural fertilizer.
Ich haben zwei Platzspielen und ein Microphone
 
jben
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 4:05 pm

There are several other problems i'd like to point out just briefly.

Firstly is the battery technology... to store enough power to make such a system worthwhile would require possibly thousands or even tens of thousands of individual cells. That is going to add an enormous amount of weight to the aircraft. We're not talking about a car weighing several tonnes and produces maybe 200 horsepower, which uses the vast majority of power on acceleration, and requires fairly minimal ongoing power to keep it in motion. No, we're talking about something weighing 200t and has to maintain the vast majority of power continuously.

One exception are some UAV's. These are different because of their very light weight (no need for life support, etc...). Heck, as NASA has showed before, you can happily run a UAV for ages on solar power. It's just not even close to the power you need for a commercial aircraft.

Secondly is the reliability and characteristics of the turbine engine. Turbines are, by and large, very effecient in providing very large amounts of power in relatively little volume. Electrical engines to produce equivalent amounts of power would be much larger and much heavier than a turbine. One way hybrids work is by capturing braking energy and using that to recharge the batteries to then run the car during driving, on an aircraft this would be almost worthless to try and transfer all that braking force to a generator to recharge the batteries. And what are you going to do with the electricity you generate?

Honestly, fuel continues to provide the cheapest, most reliable method of propulsion available.

Unless someone wants to run an aircraft on JP-7?  crazy 
 
ikramerica
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 4:06 pm

Quoting Sv2008 (Reply 8):
No, that's not right.

The electric motor is used to boost acceleration. If it cruised on the electric motor the battery would be flat in no time. Even around town the electric motor can only be used on it's own for low speeds.

Why don't all you guys look it up rather than guessing.

Further, different hybrids work differently base don their intended role.

In the USA, cars like the Honda Accord hybrid use the electric motors to provide extra power without using extra fuel. They use the same gas engine as the non-hybrid version of the vehicle (sometimes even larger), but add the electric motors to recover the wasted energy and provide extra torque at the low end and HP at the high end for better performance.

Other systems, like the Ford hybrid engine in the Escape (and siblings) is based on a small engine with more eletric power, and relies on both equally for motivation. It isn't a performance car, but it gets great mileage as a result.

The original concept of the hybrid was to use the engine as a generator and not drive the wheels directly with it at all. Combined with regenerative breaking, this concept provides power for an otherwise electric car. The engine would only come on when the power was getting low, and then it would run at optimal RPMs for efficiency to provide charge, then shut back off. This is the most efficient use of hybrid technology, but also the least "car like."

The problem with using this type of power on a plane is that unlike a car where the engine transfers it's power to the road via axles and gears, a jet engine directly powers the plane with thrust while also driving a fan to provide more thrust. You can't just turn part of it off and expect the plane to operate correctly.
Of all the things to worry about... the Wookie has no pants.
 
Alessandro
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 4:22 pm

I guess it could be used to taxi after a plane has landed, the batteries could replace some of the ballast on bigger planes. In flight, no I don´t think it would make sense. UAV use it to be quiet so avoid detection, not to save fuel.
Here´s more about ballast or counterwieght used on Boeings and McDonnell-Douglas, see http://en.wikipedia.org/wiki/%22depleted_uranium%22

[Edited 2006-09-25 09:32:26]
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N1120A
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 4:27 pm

Quoting BDL2DCA (Reply 3):
Typically, they cruise on the electric motor, and the gas engine is started to provide accelleration.

Nope, the other way around. Hence why so many hybrids have piss poor (relatively) highway economy.

Bio Diesel is a much more viable and near term solution to increasing fuel costs and pollution reduction from jet aircraft.
Mangeons les French fries, mais surtout pratiquons avec fierte le French kiss
 
jben
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 4:35 pm

To be quiet? Yes, to some degree... Although even the big UAVs like the Block 20 Global Hawk are fairly quiet and also fly very high so it's less of an issue than you'd think. However, the bigger issue is the capability of how long the UAV can remain on station, it's not as good having only 4-5 hours of loiter (or even less) over the target, then the UAV has to fly back to be refueled/maint. The really cool thing would be to have a UAV that can remain on station for days... like 3-4 days.
 
Alessandro
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RE: Is A Hybrid Plane Possible

Mon Sep 25, 2006 11:03 pm

Also less sensitive to heat-seeking SAMs I guess?
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beech19
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RE: Is A Hybrid Plane Possible

Tue Sep 26, 2006 6:23 am

Quoting N1120A (Reply 19):
Nope, the other way around. Hence why so many hybrids have piss poor (relatively) highway economy

Correct except the piss poor part. For example (and this goes for MOST hybrid cars in the US):
Ford Escape will get you 36mpg/city and 31/hwy.
31mpg on the highway for a 4x4 200hp(combined) SUV doesn't sound very piss poor to me.

Also hybrid cars in general use the electric motor around town (usually up to 25-30mph) and then when the battery starts to get low the gas motor turns on and acts as a charger but does NOT kick in untill the 25-30mph speed at which the transmission engaged the gas motor to use as the "primary" power source. When you step on the "gas" of a hybrid at BOTH motors engage and you get quite the little kick in the pants.  Smile

Back to the topic at hand... the battery cells of today would make this impossible. The 330V sealed Nickel-Metal-Hydride (NiMH) battery pack used in the Ford Escape weighs about 300lbs and as someone has already mentioned is partially charged by the regenerative braking, which last time i checked, we used flaps and spoilers to slow down.  Wink

How many hundreds of thousands of pounds of battery cell would be needed to sustain even a small airliner on any length of trip? Its not going to happen...

Quoting SK909 (Reply 10):
Hopefully we will see some hydrogen powered engines

This is the most likely next step, after an "E85" type of jetfuel, given that automobiles are headed that way already.
KPAE via KBVY
 
Alessandro
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RE: Is A Hybrid Plane Possible

Wed Sep 27, 2006 12:01 am

Beech, exactly I don´t believe in the hybrid technology when in the air, but on the ground it could be useful. I recall one accident with an Il-76 when it
hit a terminal building after the pilot had shut-off the engines prematurely
and had no electricity to controll the brakes, if a backup hybrid system been
in place this could be avoided.
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cloudy
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RE: Is A Hybrid Plane Possible

Wed Sep 27, 2006 12:40 am

I can't see planes flying using batteries or internally generated electricity,
for the reasons listed above.

What may be possible in our lifetimes(but still in the far future) is some sort of beamed energy. A microwave beam based at an airport beams power to an airplane. The plane need have only the microwave receiver and an eclectically driven propeller in addition to its jet engines. These can be made pretty light. The microwave-electric props could be used for supplemental power for takeoff assistance - this could reduce runway requirements and fuel usage in takeoff, taxi and perhaps even the climb to cruising altitude. In the real far future, microwave power beamed from space could assist in cruise.

In time, the kerosene fueled jet or turboprop engine would be reduced to an emergency device. You would need only a single engine of about the same size used to power a two engine plane of the same size today (to allow for climb without the microwave beam in a takeoff emergency). Such a plane would need only enough fuel to reach a diversion airport with a safe margin. A huge amount of energy is wasted in modern planes carrying engines and fuel as well as the structure required to support propulsion. Moving as much of the system as you can to the ground cuts down on this waste. Also, electricity for the microwave beams can be generated using any number of environmentally friendly means.

Microwave electric assist also has some long term safety benefits. Electric motors can be instantly turned off or throttled to any speed they are capable of - this is definetly not true of a jet. Since electric systems are relatively light in the abscence of large batteries, you can afford more redundancy. The plane need not have as much fuel or fuel -related hardware on board and that reduces all kinds of risks.

But this is probably a pipe dream. There are all sorts of regulatory, safety, psychological and economic obstacles to overcome. Don't look for it to happen unless the price of kerosene goes way, way high and stays high for a long time.
 
jben
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RE: Is A Hybrid Plane Possible

Wed Sep 27, 2006 10:52 am

Less sensitive to SAMs... yes. The smaller electric UAV's produce very little heat but are also very small/light and may not even appear on radar in the very cluttered tactical environment, and even if they do... they're very small and agile. The larger UAV's like Global Hawk (particularly the block 20 (which is bigger than block 10) and the coming 30 and 40, which will be even bigger than the block 20) fly very high 60,000ft+. However, in terms of active countermeasures, the Global Hawk is lacking... simply because they're already packed full of sensors in the form of the Raytheon ISS (any of you that subscribe to Flight International will remember the recent poster in the centre of the Global Hawk Block 20).
 
JayinKitsap
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RE: Is A Hybrid Plane Possible

Wed Sep 27, 2006 2:00 pm

A synthetic jet fuel that contains substantially more energy per pound (say 20% more with a comparable or heavier density) that isn't substantially more volitile would be a big hit. That would allow for all planes to have nearly 20% more range with the same weight of fuel currently.

Using anything other than liquid fueled air breathing turbine engines is probably the only possible method for at least 20 years, probably longer. A nuclear or fusion source that didn't require the extensive shielding would be probably the most promising candidate.
 
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Aloha717200
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RE: Is A Hybrid Plane Possible

Wed Sep 27, 2006 2:50 pm

I'd like to see something like this happen. The fact is though that as of right now the technology hasnt been invented for something the size of a large commercial airliner to use akin to this.

However, i think more likely than a hybrid, you will see an alternative-fuel airliner. After all, oil resources are finite, and one day will be gone. something has to replace it. but you probably wont see that happen for another 40 years.
 
baroque
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RE: Is A Hybrid Plane Possible

Wed Sep 27, 2006 5:36 pm

Quoting Acidradio (Reply 15):
I have been following a new process (thermal depolymerization) with much excitement

Don't want to rain on your happy thought, but the basis of thermal depolymerization has been around for as long as coke ovens, which is about 250 years. Yes there are some nice tricks you can play, but the basis has been there for a long time. As I wrote somewhere, only Japan as far as I know has stuck with the byproduct parts of its byproduct ovens. Many companies, such as the local Bluescope still run byproduct ovens, but closed the byproduct part 20 or 30 years, ago, partly due the OHS problems as it happens.
 
Alessandro
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RE: Is A Hybrid Plane Possible

Sun Oct 08, 2006 5:13 am

Check this thread out, Fuel Burn For Taxiing Aircraft (by Rampoperator Jan 3 2006 in Tech Ops)
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