Flying to Detroit MPG

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.

 

I would have ridden my bike, but I didn't get enough notice.

 

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.

 

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

 

No, but cars usually don't go around... and around.... and around.... like I did last time I flew into O'Hare.