When Will the Boeing 787 Finally Take Flight?

[tmyer2107]

So what really are the advantages of the 787?

I recently flew on one of Continental's new airplanes. Wasn't near as noisy and had much less turbulence than anything else I've flown in. Also had outlets at every seat and tvs in the seat in front of you, it made for a much more enjoyable flight. I would definitely pay a few extra dollars to fly in that plane again rather than another flight on another airline. I think that is going to be the biggest advantage for the 787. It will attract customers to the airlines that have them because they know they will have a more comfortable, enjoyable experience.

 

[Cyrus]

Notice the chevrons on the jet nozzle. That is very state-of-the-art right now with a lot of work being to done to understand exactly how they even work. For acoustic reasons btw.

Also, did anyone notice as the plane flew over the camera, the change in perspective gave the eerie illusion that the wings were being swept back?

p.s. As far as the differences between the 707 and 787. Well the 707 was like a 180 passenger airline, where the 787 is almost twice that. Sure, similar shape, way different scale. Lots of difference there.

So.....why don't I just upgrade the engines on my existing airplanes and save hundreds of millions of dollars?

In other words, I want to see the Cd of this airplane in a wind tunnel compared to other airplanes. If it is indeed 20% lower, I'll buy Boeings marketing ploy. Otherwise, they should just say it has 20% more efficient engines and thank whoever makes the engines. This is exactly what boeing does when selling their hummingbird helicopter. Its engine has a very low SFC, but they attribute it to its 'optimum speed rotors'...woooo optimum speed rotors yeah sure...

 

[minger]

I thought the 787 only had secondary nozzle chevrons because of the large bypass ratio. I can't tell from the videos that Ivan linked to.

They've found the chevrons to reduce acoustical waves, but don't really (that I know of) successful numerical models. From what I know they experimentally found that x number of chevrons reduced noise while y increased. If they were angled at a they reduced and b they increased.

I was recently at a conference a NASA rep was presenting some stuff on it (among other aeroacoustic research). Pretty cool stuff. They may be there for another reason, but that one I do know of.

 

[minger]

So.....why don't I just upgrade the engines on my existing airplanes and save hundreds of millions of dollars?

In other words, I want to see the Cd of this airplane in a wind tunnel compared to other airplanes. If it is indeed 20% lower, I'll buy Boeings marketing ploy. Otherwise, they should just say it has 20% more efficient engines and thank whoever makes the engines. This is exactly what boeing does when selling their hummingbird helicopter. Its engine has a very low SFC, but they attribute it to its 'optimum speed rotors'...woooo optimum speed rotors yeah sure...

Even if the Cd is the same, it has a bigger cross sectional area. In order to be bigger and consume less fuel, I would imagine the Cd would be lower. We have MUCH better tools today to help with design, which helps with that.

 

[Cyrus]

Even if the Cd is the same, it has a bigger cross sectional area. In order to be bigger and consume less fuel, I would imagine the Cd would be lower. We have MUCH better tools today to help with design, which helps with that.

I'll believe that when I see some actual numbers. Companies are notorious for marketing things in a shady way. I can show you plots of tilt rotors on helicopter websites that make them look like a godsend. I don't believe Boeing. I'm pretty sure the guys that build the 707 did a pretty good job, I don't see much difference in aerodynamic shape between those two pictures. Looks like business as usual to me. I still think its the same airplane, made of different materials (ok, kudos on that at least) with better engines (thats where the fuel savings comes from).

If their airplane is really that good and they are really proud of what they did, give a plot of Cd*A compared to other airplanes.

 

[FredGarvin]

They've found the chevrons to reduce acoustical waves, but don't really (that I know of) successful numerical models. From what I know they experimentally found that x number of chevrons reduced noise while y increased. If they were angled at a they reduced and b they increased.

I was recently at a conference a NASA rep was presenting some stuff on it (among other aeroacoustic research). Pretty cool stuff. They may be there for another reason, but that one I do know of.

I have had the chance to see a lecture from one of the head gurus at Boeing. They do have predictive models but they are still working on aspects of it. It had some really good insight into the design of the chevrons. One thing we went into a fair amount of detail on was the fact that, as bypass ratio increased, chevrons on the jet nozzle became less effective and chevrons on the bypass duct took over. One of the major tradeoffs apart from performance of the engine, was that the chevrons always slightly increased higher frequencies while helping to attenuate the lower.

I wonder if you ran into any of the folks from Glenn that we have done work with. I liked working there. What a great facility.

 

[FredGarvin]

I don't see much difference in aerodynamic shape between those two pictures.

I see a bunch of differences in the wing planform and the way the engines are hung. I see a bit in the fuselage, especially in the front.

Plus look at the differences in max takeoff weight and range. The 787 is heavier and can go as far if not farther while carrying less fuel. That is partially engines, but there has to be some good airframe improvements for that.

http://en.wikipedia.org/wiki/Boeing_707
http://en.wikipedia.org/wiki/Boeing_787

 

[lisab]

I recently flew on one of Continental's new airplanes. Wasn't near as noisy and had much less turbulence than anything else I've flown in. Also had outlets at every seat and tvs in the seat in front of you, it made for a much more enjoyable flight. I would definitely pay a few extra dollars to fly in that plane again rather than another flight on another airline. I think that is going to be the biggest advantage for the 787. It will attract customers to the airlines that have them because they know they will have a more comfortable, enjoyable experience.

Configuration (e.g., seat width) and amenies are decided by the airline, not the plane manufacturer.

 

[Borek]

with better engines (thats where the fuel savings comes from)

Lower mass doesn't play any role? Only better efficiency of engines?

 

[Andre]

Yes lower weight --> less air to push down to keep flying, -->s a lower angle of attack, ---> less induced drag --> less trust required

But the effect is largest at low speeds. Als less weight means less energy/fuel required to climb to cruise altitude

 

[mugaliens]

They all look like the same ole B-707 from 1960!

In this case, looks are definitely deceiving...

 

[Cyrus]

In this case, looks are definitely deceiving...

How so? In what way is it aerodynamically different than any other school bus they make?

http://img682.imageshack.us/img682/9573/jglt.jpg

Yeah, not impressed by the 787 so far...

Hooray for substandard improvements in technology! Hey, at least it has a fancy paint job...

 

[Ivan Seeking]

These airport delays are getting out of hand. This flight was two years late.

I told a slightly modified version of that joke to a buddy at Boeing. After a silent pregnant pause, he said he was going to hang up now.

 

[Ivan Seeking]

How so? In what way is it aerodynamically different than any other school bus they make?

http://img682.imageshack.us/img682/9573/jglt.jpg

Yeah, not impressed by the 787 so far...

Hooray for substandard improvements in technology! Hey, at least it has a fancy paint job...

What is the kts for the 787?

 

[Borek]

What is specific productivity?

 

[Cyrus]

Anyone remember this brilliant idea?

http://flyingelectrons.com/page7/page18/files/page18_2.jpg

Boeing decided it would be a good idea to cruise right at the edge of ma 1, i.e where drag is the absolute highest. I talked with a former Boeing engineer who told me the entire airplane was a marketing gimmick they had no intentions of making.

Hmmmm, let's make an airplane cruise at that peak...brilliant idea.

 

[Ivan Seeking]

The answer from Cyrus is "I don't know"?

 

[Ivan Seeking]

It is pretty tough to fake 20% better mileage.

Of course I'm sure none of the buyers have anyone who knows what they're doing. God knows that none would have a newby college grad to keep them straight.

 

[Sorry!]

Anyone remember this brilliant idea?

http://flyingelectrons.com/page7/page18/files/page18_2.jpg

Boeing decided it would be a good idea to cruise right at the edge of ma 1, i.e where drag is the absolute highest. I talked with a former Boeing engineer who told me the entire airplane was a marketing gimmick they had no intentions of making.

Hmmmm, let's make an airplane cruise at that peak...brilliant idea.

Well there are a lot of factors consider when talking about the drag caused by mach divergence... I'm not saying that it didn't impact the particular air liner your talking about but I'm sure boeing would probably have looked into technologies to further reduce the effect than the modern supercritical airfoil does.

 

[Cyrus]

The answer from Cyrus is "I don't know"?

What "answer from cyrus"? I didn't answer any specific question.

 

[Cyrus]

It is pretty tough to fake 20% better mileage.

Of course I'm sure none of the buyers have anyone who knows what they're doing. God knows that none would have a newby college grad to keep them straight.

Yeah, because its not like a leading aerodynamicist wrote the book I scanned for you. Or that I gave you something I was told by an aerodynamicist at boeing. Perhaps we should do more reading on this subject?

 

[Cyrus]

What is specific productivity?

It is defined as:

$$SP = \frac{(\mbox{Max Payload})x\mbox{(Transport speed)}}{\mbox{Max T/o Weight}}$$

 

[Sorry!]

It is defined as:

$$SP = \frac{(\mbox{Max Payload})x\mbox{(Transport speed)}}{\mbox{Max T/o Weight}}$$

I figured it was something like this, I've only ever seen the term used in biology to do with cells. So I wasn't exactly sure how it applied here. However is this diagram based on the 'low-end' models of the planes or the 'high-end' because the gap in specific productivity between even the 3 models of 787 is quite large... or does it maybe average it out or something?

 

[turbo]

It is pretty tough to fake 20% better mileage.

Of course I'm sure none of the buyers have anyone who knows what they're doing. God knows that none would have a newby college grad to keep them straight.

Prime motivation for sales. Fill the seats on popular longer runs and save a pile of money on fuel. And yes, that kind of efficiency is impossible to fake. A higher-capacity plane can also help relieve congestion in the skies and on the ground. If I were operating an airline and a manufacturer offered me a new plane that could cut fuel costs by 20% on runs like NY to LA, NY to LV, LA to Honolulu, etc, I'd sure have some orders in place. You're still going to have fees to pay at airports, catering costs, etc, but if you can make fewer flights, spreading the costs over the same number of passengers (or more passengers, perhaps) AND save 20% on fuel, that's a game-changer. I hope that Boeing gets the plane certified soon and starts cranking them out - a little bright spot in the economic gloom.

 

[Andre]

Yeah!

Observation: The chase plane wasn't exactly in the safest location, wingtip vortex-wise! Would have been tragic to get off the ground only to loose a wingtip...

Well wing tip vortices are always below the flightpath and I never say the chase that low.

 

[FredGarvin]

Hooray for substandard improvements in technology! Hey, at least it has a fancy paint job...

Come back to us when you have had a nonosecond of experience getting an aircraft FAA certified. If you had any, you would know that because of a lot of reasons you don't see huge advancements in a single aircraft and still stay in business. There is way more than simple design calculations to look at. For example, before you even begin the process of building and testing a new aircraft, the FAA has to sign off on the aspects that go into it, basically saying that whatever problems you run into they will not require breaking the laws of physics, etc...In other words, the FAA knows of all of the issues up front and they think you have a reliable approach to solving. That kind of system does not lend to massive or Earth shattering advancements in one aircraft. Slow, gradual advancements are the way to go, especially if you are embarking on a program that will cost you tens of billions of dollars. Even in your chart, look at the one data point that showed "huge jump in technology!" The Concorde. While a cool aircraft, it made 0 money and cost huge sums and was, for all intents a business failure.

I'm not defending the marketing morons. I hate them too. However, this is just a bit more complicated than that.

 

[Cyrus]

Come back to us when you have had a nonosecond of experience getting an aircraft FAA certified. If you had any, you would know that because of a lot of reasons you don't see huge advancements in a single aircraft and still stay in business. There is way more than simple design calculations to look at. For example, before you even begin the process of building and testing a new aircraft, the FAA has to sign off on the aspects that go into it, basically saying that whatever problems you run into they will not require breaking the laws of physics, etc...In other words, the FAA knows of all of the issues up front and they think you have a reliable approach to solving. That kind of system does not lend to massive or Earth shattering advancements in one aircraft. Slow, gradual advancements are the way to go, especially if you are embarking on a program that will cost you tens of billions of dollars.

<shrug> and then you build the same airplane for 40 years. You need to read the book I linked to, which explains the current problem with industry. The 787 is a perfect example of small changes due to unambitious thinking. Wow...5% better performance in 40 years. AMAZING. It's time for something that is 50% better. Helicopters suffer greatly from this very problem. There are almost no new ones built in the last 20 years, and the V-22 is a piece of heavy, expensive, junk.

I'm not being a smartass, read this book, you'll love it being a helicopter guy Fred.

 

[FredGarvin]

You have to live with the business realities before you get a job doing it. Period. To get something that is "50% better" (better in what?) there needs to be a business case and a way to fund it. Boeing and Airbus bet the farm with every new aircraft that comes out.

 

[Borek]

$$SP = \frac{(\mbox{Max Payload})x\mbox{(Transport speed)}}{\mbox{Max T/o Weight}}$$

Thanks. But if it is defined this way nothing strange there is not much that can be done, perhaps that just means we are close to the physical limits for this type of the plane. I suppose if you could plot cost of kg mile (or passenger mile), or MTBF (or some other parameter of similar meaning) against time, plot would be not that flat.

 

[FredGarvin]

I don't agree with that metric being the lone one to compare to. How about "does the manufacturer make money and continue to do business" metric? Or in the case of the Concorde, which had very few routes to fly, how useful is the aircraft for which it was designed. I can think of a hundred more parameters to judge a design against that the Concorde would fail miserably in.

 

[Borek]

It's time for something that is 50% better.

Somehow I doubt such solutions exist. After almost 100 years of polishing and optimizing every single detail in the planes I am ready to assume every reasonable approach has been tried - and those that were better were already selected. Assuming it is still possible to jump higher by 50% just by doing it differently is getting us dangerously close to those crackpots that tell us now and again that car industry hides miracle solutions for water fuelled cars.

I would love to be wrong.

 

[minger]

Right now I would say things are limited by materials. Better materials will let us run higher temperatures, which will raise efficiencies. Will you see a 50% raise? I don't think so, the thermal efficiencies of those engines are already fairly high, and Cd values are of magnitude ~0.01.

I just don't see from even a macroscopic view you can expect to get an additional 50% from.

Fred: Those are the people that I was speaking of in fact. My graduate adviser split time between the university and Glenn.

 

[Andre]

Well if you want to improve 50%, Cruise altitude and speeds are optimized, if there was anything in the design to improve, it would have been already. Also, there is not a lot more efficiency to be gained from burning liquid hydrocarbons. What kind of fuel would we be thinking off in the first place?

 

[Cyrus]

I don't agree with that metric being the lone one to compare to. How about "does the manufacturer make money and continue to do business" metric? Or in the case of the Concorde, which had very few routes to fly, how useful is the aircraft for which it was designed. I can think of a hundred more parameters to judge a design against that the Concorde would fail miserably in.

I'm not arguing that is the only metric to compare to, nor does the book. It simply illustrates a point I was making. The book also explains why the Concorde appears to be an outliner, and taken with caution on the next page (which I didn't scan).

 

[Cyrus]

Somehow I doubt such solutions exist. After almost 100 years of polishing and optimizing every single detail in the planes I am ready to assume every reasonable approach has been tried - and those that were better were already selected. Assuming it is still possible to jump higher by 50% just by doing it differently is getting us dangerously close to those crackpots that tell us now and again that car industry hides miracle solutions for water fuelled cars.

I would love to be wrong.

You'll never find a new solution building the same old airplanes. That is the point. The point of thinking is flawed in industry in terms of innovation. They only make small baby steps.