Air Travel Treehugger Style?

Amigo, you've gotta be nippin' me....

There's no way these little babies even come close to the fuel efficiency of a full sized aircraft that's reasonable full. I mean, I think it's really cool and all, but not a chance!

Plus no one is going to be able to afford this except people on big company dimes. The real sustainable future in airtravel (esperically trans-ocean) is airships! Bring back the blimp....

Authors Note: Right on- It is the way the system works that is possibly more green... If you applied this kind of customization, and systems approach to airships... I agree...Bring back the blimp.

I am familiar with this program which has been in development for several years. Eclipse is a unique aircraft that is one of the first of a new category called Very Light Jet coming to market. Many others will follow. However, the goal of these planes are not really to be green, but to offer a different option to pilots who fly personal airplanes but want to get a faster one.

While the cost of this one is around $1mill it is a lot less than the smallest jet you can purchase. In addition one of the other features this new category offers is to use only one pilot such as an owner pilot. All the others require a crew to fly which includes two pilots.

Eclipse has introduced a new method to provide a metal airplane without rivets or seams. Thus making for better airflow and reduced drag which saves fuel.

Finally if the plane is lighter weight it can go faster which can translate to using less fuel. Also jet engines are more efficient than other aircraft engines and by being smaller they burn less fuel than a large commercial aircraft.

While we compare a large SUV to a small car the same can be said for the airplane. The plane I fly burns about 10 gals of fuel an hour. While that sounds more than a car it is a lot less than larger plane in the same category. The Eclipse is a small plane in the Jet category and can save more. If people start using the air taxi then it may take some of the old less efficient large airplanes off routes which will help the environment.

The only real sustainable future in air travel is ... well... trains. air travel could be restricted to crossing oceans with a global effort to expand high speed trains. little jets zipping all over the skies, closer to communities, chugging out more CO2 per person than a 747??? No thanks!

I'd prefer a wooden sailing dhingy anyday..

There's no way these little babies even come close to the fuel efficiency of a full sized aircraft that's reasonable full. I mean, I think it's really cool and all, but not a chance!

Actually, that's all going to depend on the load factor of the Eclipse 500 and the distance of the haul. Think for a second that these flights are all non-stop, whereas a normal commercial trip is probably 2 segments. Right there, that multiplies the flown distance by 1.41 relative to the non-stop distance.

The BTU/mile for the Eclipse 500 ranges from 19,205 for a long-range haul (1,100 nm) to 30,660 for a short-range haul (250 nm), given pilot and passenger weight at around 700 lbs.

http://www.eclipseaviation.com/eclipse_500/performance/mission_profiles.html

The Eclipse 500 has a passenger capacity of 6 people. Compared to the domestic average for commercial flights, a medium-range flight with 6 passengers and a long-haul flight with 5 or 6 passengers is more efficient in terms of energy used for non-stop air distance. Short-range 6 passenger, medium-range 5, and long-haul 4 all have similar enegry intensity numbers to the average commercial flight, albeit slightly higher.

You'd be surprised at how efficient these smaller planes are becoming. I certainly was.

When will the commercial flying wing design get release? That has the potential for massive energy savings...

So, explain to me how spring break can be handled better by a bunch of small airplanes over a few big ones? I'm coming up blank as to how.

It strikes me you would need like 2x PEAK demand in terms of capacity, with most of the time them sitting around on the ground.

Authors Note: This is where that room of mathematicians, and constructal theory fits... it is all about optimizing availability. Check out the literature on systems dynamics and optimization.

I'm a computer scientist and mathematician. I'm not buying it. Yes, small flights and a stronger model for pairing passengers with flights will assure that more flights are full and that more flights are nonstop, but what doesn't appear clear to me is that this specific model is net energy efficient. Not only do we need to more clearly take into account the extra flight distances of hub/spoke, but we need to consider factors including how many of these smaller flights will truly take off with enough passengers to yield an energy savings as well as the cost of building a fleet of many individual planes versus building a fleet of a couple large planes.

I don't know the exact energy economics here, but I see a lot of hand-waving going on in this article, implying that somehow a "room full of mathematicians" can spin straw into green gold on its own. It would seem to me, though, that this is the airborne equivalent of carpooling, and that comparable energy economics would be seen in a carpool versus train-and-bus public transport. Which of these two is greener?

Either way, I really think Treehugger should be doing more to mention the greenness in articles like this. This reads like an infomercial, and NOT ONE of the three bullet points actually addresses the greenness of DayJet. In fact, two of the three bullet points speak to the efficiency of the existing system.

Sorry, guys. Where's the green?

Authors Note:
Let's break these down into conversation points.
It would be nice to have more concrete data on the energy economics of each system- as well as a life cycle analysis of each airplane or system if we can start to think in that way... Anyone?

About the bullet points- efficiency is not the same thing as sustainability! All of the bullet points question the DayJet model as a more SUSTAINABLE option as opposed to the current system (idea).

As for the mathematicians- it is about optimization of resources, building a system from the bottom-up, and responding rapidly to a changing demand. Things biology knows how to do, things constructal theory shows us how to build. This system captures that, and in doing so I think has the potential to be a sustainable option. (I like the air-ship/blimp addition)

(The founder of DayJet is also a computer scientist and mathematician of sorts_ you two sound like you have much to discuss.)

About the bullet points- efficiency is not the same thing as sustainability! All of the bullet points question the DayJet model as a more SUSTAINABLE option as opposed to the current system (idea).

You're right. As long as those planes are burning fossil fuel, we're looking at a system that is not indefinitely sustainable. So, we can go ahead and throw DayJet out as a sustainable option. In fact, we have no sustainable air travel at the moment. So, the preferable question is to look at the one that's "least unsustainable". All things considered, that will go to the least polluting and most energy efficient option.

As for the mathematicians- it is about optimization of resources, building a system from the bottom-up, and responding rapidly to a changing demand. Things biology knows how to do, things constructal theory shows us how to build. This system captures that, and in doing so I think has the potential to be a sustainable option. (I like the air-ship/blimp addition)

These are buzzwords. They don't speak to how this is "Treehugger style" travel. That's my point. "Response to demand" merely means that a plane is present at an airport when it is needed. It does nothing to speak to the four major factors in air transport-- fuel consumed per passenger per mile, pollution produced per passenger per mile, economic impact per vehicle, and economic impact of vehicle maintenance over its lifetime.

The founder of DayJet is also a computer scientist and mathematician of sorts_ you two sound like you have much to discuss.

Maybe he'd like to fly me from Boca to Gainesville to see my thesis advisor. *wink*

***
Authors Note: LOL, 'fly me from Boca to Gainesville' that is a funny :-)... You are right about the shades of gray when it comes to 'sustainability'- it is a nebulous concept itself, but I like the measuring stick of 'does it enrich the community?' and by that I mean the human and natural community. There are very few (can't think of any right now) technologies that don't use fossil fuels in some way- I agree, we should change that.

Also, I understand your argument better now- But the four principles you define as the 'major factors' (roughly: Fuel, Pollution, Price, Maintenance) in air transport are of course the same principles people used to arrive at our present system of air travel- maximizing these led to the Hub and Spoke system.

Now, I don't think it is all of one or the other- What I do think is that most industries ignore the systems approach to understanding their environment- something DayJet has appeared to embrace. This in itself is Treehugger style- thinking about the system, and creating better designs that fit with what is needed.

When we talk about those four factors in air travel they are not alone floating in space, but are impacted by real world events. The biggest buzzword for 2006 was 'Sustainability' - NOT biomimicry, constructal theory, or cradle to cradle- these are ideas, with depth and meaning. Ideas that have shown they have the chops to make positive change in our human impact on environmental systems.

DayJet does NOT advertise itself a 'green alternative'- they have said no such thing. But their systems approach and innovative technology is pushing the boundary....without realizing it- I think they are creating something that has the potential to evolve into a sustainable service. I would like to encourage them to explore that line of thinking.

Are they sustainable now? No. Are they better? I don't know.... but I'm excited to see what happens, and I would like to see more companies start to consider their business environment, and the possible impact on human and natural systems.

I know "jet engines are the term used to mean "not propeller driven" But a turbofan engine and turbojet engine are different, mainly, turbofans are more efficient but can only be used at lower speeds and altitudes. Airliners use turbofans, but small "jet" aircraft haven't been using them as long.

Well, I'll be the first to defend air travel, within reason.

But this thing gets 7.2 staute (land) miles per gallon.

Aircraft fly nearly straight routes, while most land routes have about 30% more distance even over fairly flat terrain. So a fair car equivalent mileage is 10 MPG. A Hummer.

This is green? I don't think so. Certainly not for single-person travel.

A Diamond D42 diesel piston twin gets 19.7 land miles per gallon at 173 MPH. That's about 40% the speed of the Eclipse, but nearly three times the mileage on exactly the same fuel (they both use jet A). In fact, the car equivalent mileage of a DA42 is about 26 miles per gallon, up in Toyota Camry territory but more than twice as fast over a shorter route. It seats four (pilot included).

So there is a right way and a wrong way to indulge in personal air travel, and a Very Light Jet is the definitely the wrong way.

t's not so horrible (but still hardly green), if several passengers share the ride. A full plane load is slightly more efficient than each person in their own car.

So the air taxi model is hardly progress, while the single-flyer model is a disaster. How is this "TreeHugger Style" again?

---

For you train fans, I wrote this in an earlier comment, but it's worth repeating:

"A single meter of dual railroad track, including rails, ties (usually made of concrete), and supporting gravel weighs as much as a large car. The steel alone for typical TGV track, which is not particularly heavy, weighs 60kg per meter per rail, or 120kg per track. So that a double track section 1,000 km long requires 240,000 metric tons of steel. Then there is the concrete involved. Each concrete crosstie weighs about 300 kg. There are approximately 2.5 crossties per meter, per track, so that's 5 per meter for two tracks, which is 1,500 kg per meter, or 1.5 million metric tons of concrete for that same 1,000 km of railway."

You can imagine the CO2 footprint of making those materials, shipping them and installing them. Then there are bridges, tunnels, and earthworks. Not only CO2, but habitat impact by thousands of kilometers.

And when all that CO2 is emitted to build it, you still haven't traveled a single mile. Sure, you will do so more efficiently, but it's a huge mortgage to pay up. If the route is not dense, you may never do it.

Rail is great for Europe, the Northeastern US and Canada, Japan, and similar dense populations. In Kansas or Colorado we are better off if people fly small planes, so long as they are not jets.

While I don't think that air travel is going to go away anytime soon (and so on that basis an idea that reduces the greenhouse gas emissions of air travel deserves some consideration), this article betrays the rather uncritical, consumeristic eye that TH sometimes evinces. As George Monbiot's Heat, oft-cited on these pages, points out, air travel is one thing that is never going to be eco-friendly. So please, let's be a little less gushing and little more critical (of both new consumer toys and ourselves) when it comes to things like air travel.

I don't understand how this can be seen as approaching an ecological solution (or even an improvement). Read this barely tweaked opening paragraph and try to explain it to me.

The private automobile could change how you think of ground travel - but that's the idea. Not only is the private automobile a new paradigm in travel, but it just might have the potential to be a greener way to move about the earth. The first oddity of the service is the schedule, or lack of one. Instead of the normal routine of a set number trains and buses per day, the private automobile is at the customers beck and call. Called 'per-seat, on-demand' service, when you want to travel, just get in your car and drive to your wishes. The next bit that boggles the mind is that they operate out of your own garage. Instead of walking to the train station, or even taking a connecting bus, the private automobile keeps itself operating out of local places near the customer. But, my favorite part is the automobile itself....

Authors Note: Cute changes... it makes a good point.

But the car revolutionized business, land-use, and proved to be an unstoppable engine of change- wouldn't it have been better if people tried harder 80 years ago to make it a greener product (or organize better resistance)? The model-T changed the 20th century- I think it is good to have a discussion about the changes in transportation technology today, and the valuable directions of change. The reasons why the car appeals to people still applies today- so do the consequences.

Thinking about the critical principles of why a system works well (cars work well except for all their emissions, and impact of associated industries) can lead us to solutions of how to counteract the negative impacts.

For example, in this comment series the major objection is one of fuel- but what about different fuel types? What about a Fuel Cell airplane? Or even just a battery airplane? Does that change things?

How about blimps or Aeroscraft? (I do like blimps)

These are the kind of things we should discuss, and share with corporations charging down the path of the model-T. Creating a system that can rapidly adopt to changing cultural values is an important development for the airline industry (just as it still is for cars). The systems approach of smaller scale individual air-travel may not be sustainable now- but that doesn't mean it will never be- after all, birds have figured out how to make it work.

I second the notion that a whole genre within Treehugger consists of gushing about products that have a questionable relationship to sustainability. The persistently upbeat responses of the author of this article to the responses above indicate that the author is not "getting" the problem of indiscriminant gushing.

The editors of Treehugger might try to discourage the gushing by trying to sharpen up the editorial policy of the site...

With such a personalised taxi service (flying when and where you want) I expect the aircraft would mostly be flying at less than 100% load factor most of the time. The exceptions might be when a bunch of businessmen need to travel together for a meeting or perhaps a regular commuter route.

Also to meet these very flexible demands, there's going to be a lot of repositioning of these aircraft when they'll be flying with just a single pilot on board to get them to the next appointment.

As for lifecycle energy of aircraft I don't have specific figures but large passenger jets have lifetimes iof 25+ years so their embodied energy can more or less be ignored as it will be dwarfed by its operational energy consumption. I'd expect the Eclipse's embodied energy to be a higher proportion of total lifecycle energy but still it's likely to be pretty small.

Our existing air transit/reservation system with large planes iss extremely adaptable, and can be made even more so without this kind of innovation. Once you factor in Blackberry-generated reservations, it's even more so.

If carbon pricing is added in at the reservation/purchase stage, it could be made far more environmentally sound. I could envision different credit prices for different flights. After all, the more laden a flight, the more efficient it is, providing an incentive for people to fly on well-established runs, and requiring others to pay full for less crowded runs.

I really feel compelled to continue to add to this. I don't mean to sound like I'm prosecuting some sort of flame war, because that isn't my point, but I think this discussion really begs considering a few things. One of those is that advanced mathematics and computer algorithms are already at play in our hub-and-spoke system. Airlines use a system of linear programming over dozens of variables to determine which flights to schedule, where to send planes every day, how much a seat will cost, etc. The goal of the mathematical model is to minimize the number of flights, minimize delays, and maximize revenue per flight. This system is already quite dynamic and highly adaptive.

What makes DayJet different is that they use a model that's designed around access to smaller airports, flights under 600 miles, and which focuses on availability of a plane at any given airport on the network at any time a customer actually needs it. This is really something that is achievable under our current models with some minor tweaking to allow passengers to set flight times rather than merely take them. The model has different optimization parameters, yes, but this is what makes the business model different-- it competes with regional commuter air and air taxi services, and it's not intended to be applicable to the larger system. Given its focus on availability of a plane, I would have to say, from a sustainability standpoint, that it's probably a worse choice than traditional commuter air, which would also be reflected in the projected higher price per ticket.

I'd also like to note that the theoretical concepts mentioned in this article (biomimicry and constructal theory) do not appear on the DayJet website and I'm curious as to the implication that they have been driving factors in DayJet's model.

***
Authors Note: No flame war here- I just like to play devil's advocate, and you are making excellent points throughout the conversation. It sharpens my understanding and I hope that of the readers too. That is something blogs are good at, a conversation (in my opinion)

The last question here is the one of Biomimicry and Constructal theory- these are the bullet points in the article- (resilience vs. efficiency), (building from the bottom-up), etc.... are aspects of DayJet's system.... and you are right - I doubt if DayJet is familiar with any of the sustainable concepts given- as you have shown, they are probably a worse choice in terms of fuel efficiency....

But the point I'm trying to make is NOT- hey look we should all fly DayJet - but to point out they are doing some interesting things that fundamentally take a step in a new direction (at least that is what I see). I don't think there is ever one single sustainable solution that you can just say- I'm done! and walk away. Instead it is a process of new ideas, and developing innovative technologies and strategies. I see DayJet putting more power in the hands of the consumer. As a consumer, I like having more power.

And If I was ever going to fly DayJet I would want it to be a cradle-to-cradle craft, that runs on pure good intentions (or maybe wave power stored in a Eestor battery).... I admit, it is still ridiculously expensive- probably a less efficient choice in terms of flight fuel costs- and would likely only be more fuel efficient in specific situations that would otherwise involve long truck hauls. But as was pointed out- people want more flexibility in their personal transport. DayJet is offering that, and I think instead of criticizing a clearly fossil fuel heavy industry, we should see what they are doing well and how to innovate upon the system at hand.

I also agree- the current Hub spoke system is VERY efficient....that is the issue. It is not optimal, nor does it allow for rapid change in technology or respond to customer demands (my opinion here). I see DayJet system as a more flexible platform that has the ability to evolve quicker into a greener transport...maybe I'm wrong...maybe not... but someone here hit the nail on the head, 'is this Treehugger style?' (the title does have a question mark) and if not- does it represent an opportunity? I think there is something about the systems approach that increases the technology innovation on a social and environmental and business level.

Given its focus on availability of a plane, I would have to say, from a sustainability standpoint, that it's probably a worse choice than traditional commuter air, which would also be reflected in the projected higher price per ticket.

As already pointed out, it's all dependent on the a-to-b distance and load factor of the respective planes being compared. The higher price of the air taxis are going to more be a function of the low passenger-to-personnel ratio, as well as the time, comfort, and convenience premiums consumers will be willing to pay. And during the early stages, prices will be higher simply because they need to nail the low hanging fruit (the most well-heeled customers) first to drive down operational costs over time.

Since I seem to be thinking about this today- let me add a point to the conversation that might help.

Maximizing efficiency can be stupid.

Efficiency is:
Let's smoke fewer cigarettes, instead of stopping.
Let's drive fuel efficient cars, instead of walking.

Now, naturally there are always reasons to be efficient, but in reality nothing is independent- so when you make something 'efficient' it is usually at the cost of another aspect of the system. A better way to think about is optimization.

Why does it need to be efficient? wouldn't it be better if we used a fuel that didn't need efficient use? A fuel that actually improved air quality?

What if airplanes lasted only a year? but at the end of their life they could be recycled into next years model, or composted, or turned into low cost housing materials- etc...

When efficiency becomes the goal- we have lost the game. I think it is better to innovate new strategies that benefit the entire community (human and environment). I see DayJet advancing some winning strategies- DayJet's small planes will have higher turnover, and be more responsive to customer needs, and incorporate novel technology...do they have sustainability in there yet? no- but like I said before, the power of the consumer can go a long way- I want a cradle-to-cradle airplane, that runs on wave power.

So as a consumer-what do YOU want?

As already pointed out, it's all dependent on the a-to-b distance and load factor of the respective planes being compared.

Well, we can start nailing down specifics. DayJet's website says they are focusing on flight lengths of 600 miles or less. We can also make guesses about load factor, because preferring availability and having planes function "on demand" says to me that we're going to see some pretty light loads.

The higher price of the air taxis are going to more be a function of the low passenger-to-personnel ratio, as well as the time, comfort, and convenience premiums consumers will be willing to pay.

According to DayJet's website, a major factor in an air taxi's price is that you pay for a round trip even if you don't use it. This makes sense...the air taxi has to return home even if you're not using the flight. Their site seems to imply that this is where the major component of the savings comes from. DayJet is still going to have the low ratio of passengers to peronnel and the other premiums you've mentioned.

Well, we can start nailing down specifics. DayJet's website says they are focusing on flight lengths of 600 miles or less. We can also make guesses about load factor, because preferring availability and having planes function "on demand" says to me that we're going to see some pretty light loads.

It's impossible to tell a priori what their average load factor is going to be. As you know, those numbers fluctuate pretty widely even among the majors in commercial aviation. All we can determine are good guesses as to fuel efficiency given specific distance and load factor scenarios, which Eclipse plays out on their website (which I referred to earlier).

I'm also pretty sure the whole point of this venture is that they're confident they can get fairly high load factors yet still have pseudo-on-demand service. From what I have read, the way it will play out is that a customer would come to the website and try to make a reservation, then the algorithms will push back a price. It's all dependent on the size of the time window the customer puts in.

CNNMoney recently had a piece on this. It's a bit of a long snippet, but I think it's fairly descriptive of how this is planned to work.

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DayJet will not be for everyone. It's targeted initially at business travelers who take trips by car because they have no alternative. These are people who make more than $100,000 a year and would happily pay a little more if it meant getting home a day earlier. "It's about time," Iacobucci says, repeating DayJet's tagline. There's no onboard bathroom because the longest DayJet flight will be 600 miles (two hours).

How much a DayJet flight costs will depend on how flexible a traveler's schedule is. The price of each flight will range from $1 to $3 per mile. A 329-mile, one-hour flight between Boca Raton and Tallahassee, for example, will cost nearly $1,000 each way if the traveler can't give DayJet more than a 75-minute window to work with.

But if the customer agrees to fly anytime between, say, 7 a.m. and 1 p.m.--a six-hour window--the flight might cost only $329 each way. The wider the window, the more options DayJet has to meet the reservation.

Behind this reservation system is really complicated mathematics. It's basically a resource-allocation problem. Given a certain number of planes, routes, and existing reservations, what is the optimal way to reconfigure DayJet's network of air taxis to accommodate each new reservation request?

"We'll have to evaluate billions of options and come back to you with a yes or no answer in five seconds," Iacobucci says. Even a supercomputer would have trouble doing that.

Instead of a supercomputer, Iacobucci has two Russian mathematicians, Eugene Taits and Alex Khmelnitsky, stashed in a windowless room down the hall working on an algorithm they believe will solve the problem. At DayJet, everyone calls them the rocket scientists. Their algorithm quickly creates a best guess as to whether DayJet can meet a request and at what cost. As long as it comes up with an acceptable answer, it can offer a quote.

From the time a quote is given until just before the flight plans need to be filed, DayJet's system can keep trying to come up with an even better answer that lowers the total cost of the air-taxi network. On rare occasions, that might mean three different planes taking three passengers to the same place, if that's more efficient for the overall network.

Entrepreneur finds 'suite' dreams
To test this algorithm, Iacobucci is working with some operations research scientists at Georgia Tech who do have access to a supercomputer. It takes them 24 hours to come up with the same answers DayJet's optimization algorithm comes up with in a few seconds.

In another office farther down the hall (these have windows), Iacobucci keeps his ant farmers. They are complexity scientists, originally from the Santa Fe Institute, who have created a massive simulation of the entire U.S. transportation system. They've mapped travel patterns into 10-square-mile blocks, complete with income levels, demographics, historical driving patterns, airport drive times, and airline schedules and fares.

"It's like Sim City on steroids," Iacobucci says. After calibrating the simulation to match current travel behavior, the ant farmers introduce DayJet service in different cities and see how the simulated people react. That's how the DayPorts are selected.

http://money.cnn.com/magazines/business2/business2_archive/2007/04/01/8403369/index.htm

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I'm not going to attest to whether this is step forward or backwards, ecologically-speaking, but it certainly is fascinating. But I think it's safe to say it's a step forward compared to private charters as they are now.

Yup, I agree with the last point.

It is indeed a step forward compared with the big charter industry.

But but but, the rebound effect. If planes are more efficient, then the general cost of flights is lower, then more people have acess to plane travel, then the suppply rises to match the demand and the GHG emissions are increasing again.

This is a market mechanism that can hardly be corrected, if not by tough regulations.

Very interresting points thou.

Romain

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