Recently someone posted a comment about the hypocrisy of foreign auto company executives flying to the South to setup car plants. I pointed out that the absence of bridges over the Pacific, Atlantic and Polar Oceans made such a drive impractical. But there has been a hint of resentment about flying to Detroit to see the new 2010 Prius: 35 passengers shared the jet I rode 3,600 lbs of fuel burned 517 air miles 37 air miles per gallon per passenger mile 650 land miles (Google maps) 51.2 land miles per gallon per passenger mile Given the winter air temperature range of 10-37F, I would have only gotten about 42-48 MPG had I driven my 2003, NHW11. Furthermore, it would have taken about 14 hours. Although the flight time was less than 2 hours, with airports on each end, the total was closer to 4 hours. What I've learned on this trip is the 2010 Prius would probably have gotten 50-55 MPG. It still would have taken 10 extra hours but with the 2010, we have a vehicle that can with a single driver achieve airline-like, fuel efficiencies. Bob Wilson
Wow, you were on a smaller plane than many. I think the 757-200 series we took (non-stop from LAX) seats around 240 people, and it was a full plane. Some of the largest planes have the highest mpg per passenger, too ... on the relm of 60mpg.
And if you carpooled in the Prius, five people per car, and maybe squeeze and extra two or three in the trunk? There is nothing hypocritical about what the foreign auto execs did - they built auto plants to produce millions of high mpg vehicles. I don't think the little bit of jet fuel they consumed offset that.
Bob, I get your drift, but there is something seriously wrong with your math and your units. I think the units you were striving for were passenger miles per gallon, not miles per gallon per passenger mile. Also the ratio of air miles : land miles should be the same as the ratio of passenger air miles per gallon : passenger land miles per gallon, and it's not.
airplanes don't have roads, stopsigns, detours, gas stops, traffic, and the "Wth i'm lost" mileage penalty.
Had you taken three passengers along, you would have gotten more than 200 passenger miles per gallon. And while the four of you would have wasted 80 man-hours round-trip, you probably would have come up with solutions to most of the world's problems.
It seems like he's in the ballpark. 3600 lbs fuel / ~8lbs/gal = 450 gallons 517 air miles * 35 passengers = 18095 passenger miles 650 land miles * 35 passengers = 22750 passenger miles 18095 air pass miles / 450 gallons = 40.2 air pass miles / gal 22750 land pass miles / 450 gallons = 50.5 land pass miles / gal The difference between Bob's numbers and mine is probably just my being too lazy to go look up the actual density of jet fuel. Of course, on the train (if we had decent rail service) it would have been more like 200-400 pass miles / gallon Also I'm not sure carbon and pollution emissions and petroleum consumption are equivalent gallon for gallon between gasoline and jet fuel. Rob
BTW planes are not that awful per mile, its the number of miles that gets you. Most sites seem to estimate CO2 output from air travel per passenger at ~1 lb CO2/mile. A cross country roundtrip would rack up about 7000 miles, or 3.5 tons of CO2. Thats a lot, considering the EPA estimates an average 15,000 mile per year 46mpg Prius puts out 4.0 tons per year. Modern high speed rail is estimated at more like 0.1 lb/CO2 per passenger, or about 90% lower than air travel. Rob
Jet fuel density is about 6.7 lbs/gallon depending upon the temperature of the fuel when it is loaded, which would make the numbers a little worse for the jet. The OP probably flew on a 50 seat-ish regional jet, and I suspect that it burned a little more than 3,600lbs. of fuel block-to-block on that 517 air-mile journey, but I could be wrong. Regional jets are the least fuel efficient of all the types of airliners out there, which is why there was/is such a big push to eliminate them when fuel prices spiked.
It was a Bombardier CRJ200 Canadair regional jet. The passenger count, fuel burn, and air distance were provided by the flight crew. The ground distance from Google maps. Everything else was calculated from the independent values. Bob Wilson
About halfway down this page BTS | Table 4-21: Energy Intensity of Certificated Air Carriers, All Services (a) We see that by 2006 assuming all full seats, domestic ops were 55 mpg and international were 46. Even at 70% occupancy this is better than I would have guessed. In my case I would have traveled from Philadelphia to Los Angeles anyway and made a detour through Detroit for the Prius thing. By direct air distances this added 32 miles to my travel. Probably few others did this well? Anyway, the other 17400-ish miles I flew overall for this China/US trip are my own footprint.
I thought the issue was that, even with their companies going down the tubes, and begging for taxpayer money, they thought nothing of selling their multiple corporate jets? Not that the jets' fuel economy was all that bad, although I'm sure that was a minor issue in comparison.
Bingo, the hypocrisy was not that jets are a bit of a fuel hog, but the whole "We're broke and we need bail out loans" yet flew into washington on their private jets
And just to "muddy the waters", I doubt very much -any- of the companies actually -owned- the jets. They lease them from companies who specialize in that as well as operating them. There IS a failure in this thread to amortize the airliner cost over its' lifetime, as well as comparing the CO2 and other environmental costs of actually -building- it and the Prius. But I'll cut everyone some slack. Bob was just making an observation, not an accurate calculation.
That's interesting. If I drive to Kansas City to visit our daughter, with the wife and I in our Prius, we'll use about half as much fuel than if we flew. I've always wondered about that... thanks, Harry
Flying has always been a trade-off of convenience and time vs. economy. Driving my Prius to a destination may consume 6-7 gallons of fuel over 4.5-5.0 hours (rough estimate), whereas flying a Cessna 182 may consume 25 gallons of leaded fuel (that is generally 2-3x as expensive as regular unleaded) over 1.8-2.0 hours (more direct). The plane is already bound to be less efficient (commercial jets are no exception, the economies of scale are just slightly more favorable). Therefore, for a trip, I'd rather have most or all of my seats full as I'll likely burn almost as much going solo. The plane generally burns a minimum amount of fuel at a cruise speed, and that fuel burn only increases fractionally compared to baseline as the gross weight gets heavier, while cruise speed decreases somewhat as the wing's angle of attack changes to carry the load at the chosen speed, increasing induced drag. The choice is usually made with the thought of being able to do something with your day for short turn-around trips vs. consuming the day (or days) driving to/from your ultimate destination. If saving money and contributing less overall impact is my goal, I'll drive the Prius and know that I'm going to burn half a day getting there. If I only have a couple of days to start with, I'll choose to fly and eat the costs.
No, but cars usually don't go around... and around.... and around.... like I did last time I flew into O'Hare.
