sandiaman
Posts: 85
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Seattle PI Article - 7E7 Bleedless Engines

Thu May 20, 2004 5:26 pm

Good article on the "electric airplane" from the Seattle Post-Intelligencer

http://seattlepi.nwsource.com/business/174159_electric20.html

[Edited 2004-05-20 10:27:16]
 
Hamlet69
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RE: Seattle PI Article - 7E7 Bleedless Engines

Thu May 20, 2004 5:48 pm

Very good article! We are now starting to see the technical aspects of Boeing's claims. I can see the airline's hesitation in regards to initial reliabilty, however, as this definitely will be a departure from the norm.

Thank you for bringing this to our attention.

Hamlet69

BTW - reliable reports now state CASC, the buying arm of the Chinese airlines, will place a 7E7 order next month. All six majors (Air China, China Southern, China Eastern, Shanghai, Xiamen, Hainan) are expected to take part. Intial understanding is that the total order will be larger than ANA's 50-frame launch order. Unclear whether this includes or excludes possible options.
Honor the warriors, not the war.
 
Navion
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RE: Seattle PI Article - 7E7 Bleedless Engines

Thu May 20, 2004 9:21 pm

Excellent article. Unfortunately, I think it's a bit much to expect most members of this forum to actually read a full article. This forum tends to like slogans and short blurbs which are short on analysis and perspective. Thanks for the link.
 
atcboy73
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RE: Seattle PI Article - 7E7 Bleedless Engines

Thu May 20, 2004 9:34 pm

Yes, great article.

Sounds like those who said Boeing was failing to develop something truly revolutionary didn't know what they were talking about.

Just think if they redesign the other families of aircraft. Talk about an efficient fleet.
 
Danny
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RE: Seattle PI Article - 7E7 Bleedless Engines

Thu May 20, 2004 10:04 pm

"Sounds like those who said Boeing was failing to develop something truly revolutionary didn't know what they were talking about."

Engines were not developed by Boeing  Big grin
 
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Starlionblue
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RE: Seattle PI Article - 7E7 Bleedless Engines

Thu May 20, 2004 10:28 pm

Just think if they redesign the other families of aircraft. Talk about an efficient fleet.

I think current operators would scream bloody murder if they did that all at once. Commonality out the window.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
MidnightMike
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RE: Seattle PI Article - 7E7 Bleedless Engines

Thu May 20, 2004 10:37 pm


Wow, some really good information in there, and we are still years away from seeing the completed project!
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Navion
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 2:12 am

Danny, I think you miss the point. The technology isn't just the engines. You can't just "hang these engines" on any other aircraft. The aircraft will have to be re-engineered in total resulting in the exchange/removal of pneumatic piping, wiring, computer systems etc. The AIRCRAFT itself is highly evolved from any other airframe out there and no one else (i.e. Airbus and the A330) is going to just adapt their airframe to these engines without MASSIVE re-engineering and the removal of virtually ALL bleed air systems throughout the aircraft, replacement with new electrically based systems which are much more efficient. It appears you did not read the article which would have saved this post.
 
Guest

RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 2:22 am

I think current operators would scream bloody murder if they did that all at once. Commonality out the window.

Considering the 737 replacement and probably 777 replacement down the road will all share the same cockpit.... Commonality matters yes, but a significant improvement in aircraft efficiency will more than offset crew training. Aviaiton has to evolve. Glad to see it happening.
 
Danny
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 2:26 am

I just think some of you guys are overexcited about 7E7. I did read the article. Interesting indeed. But they forgot to mention what to do if electrical system fails in flight. No deicing, ups, no brakes, sorry.
Also - bleed air installation won't be removed as you mentioned since still some bleed air is needed. The plane won't be bleedless - it will just use much less bleed air that current planes.

They also mention that they are still working on figuring out how to connect 7E7 to external power. This is very basic thing.

Overall I think 7E7 may potentially be excellent and revolutionary aircraft but it's just too early to say that. Lets wait few years for the final product.


[Edited 2004-05-20 19:28:26]
 
Guest

RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 2:52 am

I just think some of you guys are overexcited about 7E7. I did read the article. Interesting indeed. But they forgot to mention what to do if electrical system fails in flight. No deicing, ups, no brakes, sorry.

Said the same about EFIS and FBW.

Also - bleed air installation won't be removed as you mentioned since still some bleed air is needed. The plane won't be bleedless - it will just use much less bleed air that current planes.

If you read, you'll see it says for stability at idle power. My understanding is that the air will simply be spent to the outside at idle power, or compressed for balance.

"On the 7E7, Boeing will eliminate this bleed air, other than a tiny amount to help with engine stability at idle settings."

They also mention that they are still working on figuring out how to connect 7E7 to external power. This is very basic thing.

Not if the plane is operating on AC not DC. Current aircraft are all DC.

Overall I think 7E7 may potentially be excellent and revolutionary aircraft but it's just too early to say that. Lets wait few years for the final product.

The glass isn't half empty, it's half full.

 
ha763
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 9:52 am

With 6 generators, 2 on each engine and 2 on the APU, I doubt you will need to worry about losing electrical power.

Also, Boeing is figuring out how to start the engines with ground power, not how to connect the aircraft to ground power. Quote from the article:

"We are now going through the process of figuring out how to configure the plane to accept external electrical power to start the engines," Sinnett said.
 
Okie
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 10:30 am

WiFi the Dreamjet
As stated in the article all these technologies have been out there for sometime, just never this much advancement put all together at one time.
The only problem I see with the external electrical power to start the engines is that the airlines are going to have to make a capital investment of a 7E7 "start cart" for the facilities and alternates that they operate. The future operators of the 7E7 are most likely just bowing up a bit due to the capital investment costs for a start cart sitting at an alternate that may only be used once every couple years when they have "huffers" sitting everywhere.
Boeing/Engine manufacturers will just be driving what ever "standard that is determined" for the start cart that will work on all future all electric planes.
It won't be any more painful than jumping from 3.1 to 95, 98, XP, then Longhorn.

Okie
 
CWUPilot
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 10:53 am

Thanks to the aviation and technical expertise of many seattle aviation reporters, I think we'll see quite a few more articles of this type coming out over the next few months. Boeing is really goint all-out on this one and I think we'll see a fantastic aircraft. As for those who are worried about reliability and redundancy, NOTHING in modern airliners will be produced that is not reliable and doesn't have a back up. Go Boeing!!!

-CWUPilot
"The worst day of flying still beats the best day of real work."
 
N79969
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 11:45 am

I also think it was a great article. Until I read that, I did not know how Boeing planned to achieve 20% savings over the 330-200.

Danny,

Current transport category airplanes are designed to have quite a bit of system redundancy. In order to receive a type certificate, Boeing will have to demonstrate how the airplane can safely endure multiple system failure modes. If you're interested in reading what is required, check out part 25 design regulations:

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=021edc61aee0f4baacb18af8bbe180a8&rgn=div5&view=text&node=14:1.0.1.3.10&idno=14

Additionally, they have to sell these airplanes to part 121 airlines so Boeing will have to keep the constraints of the operating rules in mind.

Having said all of that, I can understand why airlines are a little nervous at such revolutionary change. The mechanics and engineers will have to be re-trained to understand such a radically different airplane. But Boeing has a pretty good record of delivering on its promises.

A

 
LineMechQX
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 12:13 pm

"I did read the article. Interesting indeed. But they forgot to mention what to do if electrical system fails in flight."
Don't forget Pneumatic systems aren't 100% reliable either, ducting can fail, valves can fail, the computers driving the valves can fail. Seems to me that 2 gens. per engine is more then reliable then one bleed source per engine (one at any given power setting that is) also I imagine a RAT would still be available and for the most crucial systems, inverting DC batteries may be a possibility.

"Not if the plane is operating on AC not DC. Current aircraft are all DC."
What modern commercial jet doesn't use 400 hz AC power?
Sounds like the plan on the e7 is to skip the CSD's and go solid state to convert the variable freq. to constant for the systems that need it. Much similar to a Dash-8's power system.

"Also - bleed air installation won't be removed as you mentioned since still some bleed air is needed. The plane won't be bleedless - it will just use much less bleed air that current planes."
The article only mentioned bleed air being used at idle power for stability through BOV's (bleed off valves) I'm sure only, meaning the bleed air will be sent straight out the side of the cowl. I'd have to take a guess that this may be used to prevent compressor stalls as well, when changing power settings, but never having worked on a bleedless engine I can't be sure this would be required.
 
AvObserver
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 2:25 pm

I stand corrected in my reference to the 7E7 as basically an 'evolutionary' airplane. It really is more that that, given all of this technological change. I guess in many ways, aside from the basic airframe shape, it will be quite revolutionary. But it figures, if Boeing must deliver the claimed economics, that it must depart from design norms in quite a number of areas. Perhaps, it's even the beginning of an airliner design renaissance. Awhile back, I wasn't sure Boeing was still capable of this, being seemingly mired in "derivatives, unlimited" philosophy but it looks like they're finally starting to climb out of that rut. Guess like so many of us, they work best under pressure.  Smile
 
Vorticity
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RE: Seattle PI Article - 7E7 Bleedless Engines

Fri May 21, 2004 2:52 pm

From an engineer's view, if you ask some engineers, they'll say the 7E7 isn't revolutionary enough. Some would love to just let lose some of market constraints and come up with something really innovative, like a blended wing body.

The change in electrical systems however seems like a reasonable advance in technology, and hopefully will influence and improve designs for years to come. Progress is fun!

As far as redundancy, the engineers will be well aware of certification requirements. Some people specialize their careers in redundancy trees and things of that nature. They won't design something that can't get certified, or would be prone to single failures, that would just be silly  Smile
Thermodynamics and english units don't mix...

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