Boeing 787 Aerodynamic Report

[RobertSmalls]

Boeing 787 Dreamliner : Analysis

I came across this breakdown of aerodynamic drag and mass for the Boeing 787-8. This vehicle has a 33,000 gallon fuel tank, and seats 224 passengers. It gets 0.3mpg at 560mph, or around 67 passenger*mi/gal. That's slightly worse than an Insight with one empty seat, but the aircraft can travel in a straighter line.

 Zero-Lift Component Breakdown (Drag Areas,= Cd*S = D/q)
 -----------------------------

 Wing                   18.313  sq.feet    (37.0 %)
 Winglets                0.143  sq.feet    ( 0.3 %)
 Fuselage & fairing     19.367  sq.feet    (39.2 %)
 Stabiliser              4.049  sq.feet    ( 8.2 %)
 Fin                     2.975  sq.feet    ( 6.0 %)  
 Nacelles (total)        4.591  sq.feet    ( 9.3 %)
 User CdS Increment      0.000  sq.feet    ( 0.0 %)
                       -------             --------
 Total Cd0*S            49.438  sq.feet    ( 100 %)

In other words, this aircraft has the aerodynamic drag of ten Honda Insights*.

The good news is that aircraft are very carefully designed, with fuel economy as a very high priority. All components, even interior ones, are scrutinized for their impact on fuel economy.

The bad news is air travel makes it easy, if not cheap, for a family of five to pile into a 787 and fly across the country, burning 400 gallons of fuel in the process. If air travel were not available, perhaps they'd pile into the Prius for a 15 hour trip, burning 20 gallons instead.


*sort of. That's the 787's non lift-induced drag, which is only 52% of the drag it sees in flight. Also, the Insight is operating in ground effect. Its drag coefficient would be lower if the road weren't blocking the flow of air.

[jakobnev]

If air travel were not available, perhaps they'd pile into the Prius for a 15 hour trip,

Or a bus or a train.

[user removed]

Good to hear from you Robert. For a while I though the aliens had taken you to another planet.

regards
Mech

[kach22i]

Originally Posted by RobertSmalls

In other words, this aircraft has the aerodynamic drag of ten Honda Insights*.

A fascinating perspective and context.

There was supposed to be a major shift from the hub and spoke system which involves longer and longer delays, bottle necks and other air travel problems. Smaller fuel efficient planes utilizing secondary airports/strips, and aircraft like the ill-fated Eclipse 500 were supposed to be part of this master plan.

Publication Date: June 19, 2001
Amazon.com: Free Flight: From Airline Hell to a New Age of Travel (9781586480400): James Fallows: Books


Prior of 9/11/2001 NASA was promoting this shift in air travel, but I assume security concerns of more but smaller planes in the air and additional check points has put it all on hold.

The reason I mention this is that the air routes are not so direct, and the stops don't often match the destinations, meaning longer trips burning more fuel.

In addition, the circling in circles to get an opportunity to land, and the waiting on the tarmac for a chance to take off, burn many more millions of gallons of fuel, and all wasted for not.

[tortoise]

Originally Posted by RobertSmalls

[In other words, this aircraft has the aerodynamic drag of ten Honda Insights*.

The aerodynamic drag of ten Insights going 560 mph, that is. (Wouldn't that be fun?)

I believe drag coefficents on aircraft are calculated using area in plan view (from above or below) rather than frontal area.

[jamesqf]

Originally Posted by RobertSmalls

That's slightly worse than an Insight with one empty seat, but the aircraft can travel in a straighter line.

But only between large airports, which are often nowhere near where you're starting from or going to.

[Cd]

On my last flight, I noticed how sparse that the plane was and asked the stewardess if this was common.
She replied that flights were always empty on certain days. One flight had a single passenger.

This throws the idea of "miles per passenger" out the window.

To make matters worse, as mentioned above, a large amount of fuel is wasted going in circles while waiting to land.

To fly from Austin, Texas to Winnipeg, Canada , I was surprised to see that I had to fly a huge triangle versus a straight line - Austin to Houston to Chicago to Winnipeg.

As we would near our destinations , I could hear the pilot lower the gear despite being ten minutes away away from landing. I could literally feel the drag pulling the plane .

I'm sure there is a safety related reason for lowering the gear several miles away from the airport, but it still makes me cringe every time it happens.

[GRU]

agreed, sometimes i wonder why people brag about taking 1 hour flight which took 5 hours total to get from point A to point B when they could have just taken their car for a 4 hour trip and eliminated the process of checking baggage, waiting on the plane and airport, taxi and other things involved when flying.

[t vago]

I wholeheartedly agree. After all, why fly when you can take at least 5 times as much time to get to the destination, spend hundreds of dollars in gasoline, get added wear and tear on your vehicle (or spend even more for a rental), run a much higher risk of getting into an accident, stop every few hours to take a bathroom break, run into delays due to road construction, and deal with thoughtless jerks ahead of you who either slam on their brakes every time they see a cop parked on the side of the road or who practice extreme hypermiling in the passing lane of the highway or who text and drive.

You're right - people really should drive instead of fly. How dare they choose to spend their money as they see fit!

[renault_megane_dci]

Originally Posted by t vago

I wholeheartedly agree. After all, why fly when you can take at least 5 times as much time to get to the destination, spend hundreds of dollars in gasoline, get added wear and tear on your vehicle (or spend even more for a rental), run a much higher risk of getting into an accident, stop every few hours to take a bathroom break, run into delays due to road construction, and deal with thoughtless jerks ahead of you who either slam on their brakes every time they see a cop parked on the side of the road or who practice extreme hypermiling in the passing lane of the highway or who text and drive.

You're right - people really should drive instead of fly. How dare they choose to spend their money as they see fit!

Why the irony ?
There is a distance under which flying is not a very smart option and one over which driving is not smart either.

Any transportation can be mis-used, it is not a reason to slash it.