F4f3a From United Kingdom, joined Jul 2004, 246 posts, RR: 0 Posted (9 years 4 months 1 week 1 day ago) and read 3008 times:
Looking at the specs for the 7e7 it looks like Boeing will have to overcome some issues.
The 7e7 is mostly composite and from my knowledge on the subject I know that composites can be troublesome regards to manufacturing. Composite components have to be flawless. I don't think they have been used on such a large scale before either.
I wonder if the reason the production numbers in the first few years maybe small while Boeing finds better ways to mass produce the a/C.
The high humidity that will be in the cabin (70%) means that approx three times the force exerted on the airframe. All these new innovations on one plane are good but make me feel wary.
I hope Boeing is not going to have a comet on their hands when new tech brings new problems.
Leelaw From , joined Dec 1969, posts, RR: Reply 1, posted (9 years 4 months 1 week 23 hours ago) and read 2968 times:
Interesting comments. IMO, Boeing is genuinely pushing the envelope in terms of technological advances with this program. However, they needed to do something on the scale of the 7E7 to counter the onslaught from Airbus. Time will tell whether they can pull off something this ambitious at the promised price.
F4f3a From United Kingdom, joined Jul 2004, 246 posts, RR: 0 Reply 2, posted (9 years 4 months 1 week 23 hours ago) and read 2964 times:
Yes i think if they can pull this off they will make it if they dont they could be in trouble. If the 7e7 is very successful then im sure we will see derivetives in the form of a new 737 777 and even 747. Will be nice to see
KBUF737 From United States of America, joined Dec 2003, 779 posts, RR: 3 Reply 4, posted (9 years 4 months 1 week 23 hours ago) and read 2939 times:
When Boeing built the 747, they bet the company that it would succeed, there were many who were skeptical, today many have been built and it carries pax to the far reaches of the world.
When Airbus introduced fly by wire everybody was freaked out. Nobody could comprehend that a computer would take place of hydraulics in the control column. It scared a lot of people and there was much skepticism. Today airbus is the largest plane manufacturer in the world, and a huge advancement has resulted out of FBW.
Now it is Boeing's turn to make a contribution to the advancement of technology. They have a product with high expectations. The skeptics will be there, but Boeing is willing to take a bet that the 7E7 will be a success. If it is the aviation industry will have taken a huge step foreword.
F4f3a From United Kingdom, joined Jul 2004, 246 posts, RR: 0 Reply 5, posted (9 years 4 months 1 week 23 hours ago) and read 2899 times:
yes i think they are still going to use a 747 guppy
I think that the technology to be used is the way forward but im worried what the cost will be.
Im sure we all remember the early accidents that the a320 had before the technology was mastered.
I know with computer modeling a lot of testing can be done even before the a/c is built. There always has been however examples in the past when we thought we had reached a zenith in technology but then we were proved by events that we still have a lot to learn.
This maybe over skeptical but I think I might wait a short while before traveling on it just in case there are a few surprises.
N328KF From United States of America, joined May 2004, 6344 posts, RR: 3 Reply 8, posted (9 years 4 months 1 week 20 hours ago) and read 2765 times:
Thank you, Yoda.
No, they have never built a civil aircraft with those specs. However, the B-2 is no small aircraft, and the V-22 also has a large amount of composites. The key differences there are the pressurization and humidity, but I can't imagine the latter to be a large technical hurdle.
When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' T.Roosevelt
BCAInfoSys From , joined Dec 1969, posts, RR: Reply 9, posted (9 years 4 months 1 week 20 hours ago) and read 2752 times:
I'm not worried about it. We have the best engineers in the world. And sure we're pushing boundaries, but that's what we do best! I wouldn't want to work for a company that didn't push our imaginations, didn't strive for greatness.
I myself have taken a tour of the building where they do the composite manufacturing for the wings and the aft fuselage of the F/A-22. This is also where they're going to do the first few 7E7s, while we get our infastructure in place. It also allows our Commerical employees to learn from the experience that our Defense employees have with the practical manufacturing of composites. Trust me.. there will always be issues to work out; but when the 7E7 climbs into the air, it all be worth it. As our motto goes...
Radelow From United States of America, joined Jul 2004, 426 posts, RR: 3 Reply 10, posted (9 years 4 months 1 week 19 hours ago) and read 2687 times:
Someone please explain to be how humidity effects pressure? I guess that water is less compressable that air so that might play a factor but I am no engineer (Real Estate's my game). I thought that the reason existing planes don't have high humidity is because of the corrosion of metal etc. Also I believe that Boeing it looking to keep the cabin at a lower effective atmosphere. Now THAT will indeed increase pressure on the airframe.
F4f3a From United Kingdom, joined Jul 2004, 246 posts, RR: 0 Reply 12, posted (9 years 4 months 6 days 21 hours ago) and read 2389 times:
January 1992: 87 killed when A320 crashed in Strasbourg.
February 1990: 90 killed when A320 crashed in Bangalore.
June 30, 1994
Location: Toulouse-Blagnac, France
Operator: Airbus Industrie
Flight #: 129
Route: Toulouse - Toulouse
AC Type: Airbus A330-321
cn / ln: 042
Aboard: 7 (passengers:4 crew:3)
Fatalities: 7 (passengers:4 crew:3)
Date: January 20, 1992
Location: Mt. Saint-Odile, near Strasbourg, France
Operator: Air Inter
Flight #: 148
Route: Lyon - Strasbourg
AC Type: Airbus A320-111
cn / ln: 015
Aboard: 96 (passengers:90 crew:6)
Fatalities: 87 (passengers:82 crew:5)
Summary: The aircraft hit a mountain while on approach to Strasbourg. Design deficiencies with the mode selector switch. An incorrectly set flight control system resulted in an excessive rate of descent that went undetected. The crew inadvertently selected 3,300 fpm descent rate on approach instead of 3.3 degree flight path angle.
Summary: The plane crashed after demonstrating a simulated engine failure on takeoff. Caused by a number of factors relating to the test and actions of the crew none of which singley would have caused the crash. Unexpected mode transition to altitude acquire mode during a simulated engine failure resulted in excessive pitch, loss of airspeed, and loss of control. Pitch attitude protection not provided in altitude acquire mode.
from bbc website and plane crash info.com
The point being that whether in the case of the A320 and problems with the Man-machine interface or software porblems or problems in construction. New technology gives huge benefits but with these benefits comes new risks and problems. Which inturn lead to overcomming them.
My question was not meant to be a dig or a worry mongering one but more a request for more information. There seems to be questions on potential hurdles to this new technology and not much publicised answers. Possibly because 'how' might be a trade secret who knows
McGoose From Sweden, joined Aug 2004, 37 posts, RR: 0 Reply 13, posted (9 years 4 months 3 days ago) and read 2271 times:
Increasing the humidity to that level is simple. The problem is to get all the excess water from insulation and the electric systems. AFAIK humidifiers have been (quite) common in cockpits and crewrests for quite some time but the problem has been the unwanted condense they create. With a solution to this, humidifiers will probably become more common in both cockpits and cabins.
Klaus From Germany, joined Jul 2001, 21346 posts, RR: 54 Reply 14, posted (9 years 4 months 2 days 22 hours ago) and read 2180 times:
F4f3a: Summary: The aircraft hit a mountain while on approach to Strasbourg. Design deficiencies with the mode selector switch.
That´s apparently been a problem in the visual component of the FMS/Autopilot design. Nothing to do with FBW whatsoever as far as I can see.
F4f3a: Summary: The plane crashed after demonstrating a simulated engine failure on takeoff. Caused by a number of factors relating to the test and actions of the crew none of which singley would have caused the crash. Unexpected mode transition to altitude acquire mode during a simulated engine failure resulted in excessive pitch, loss of airspeed, and loss of control. Pitch attitude protection not provided in altitude acquire mode.
According to AirDisaster.com: "The aircraft crashed during a flight test in which the crew was simulating an engine failure on takeoff. Pilor error, misunderstanding of auto-flight systems."
Again, doesn´t look like a problem of the FBW systems.
It´s tempting to always blame the FBW systems for everything that ever goes wrong - but I´ve not yet seen convincing evidence of that actually being the case.
Klaus From Germany, joined Jul 2001, 21346 posts, RR: 54 Reply 15, posted (9 years 4 months 2 days 22 hours ago) and read 2163 times:
McGoose: Increasing the humidity to that level is simple.
Your arguments notwithstanding, I see the problem that you´d need to carry the additional water in a tank (possibly by enlarging the existing one), as the air at altitude is extremely dry. And recirculating the air humidity would simply be an invitation for every kind of microorganism to spread around... I don´t think it would be all too pleasant that way.
So you´d need to pay for the extra humidity with a weight increase and potential hazards to passenger health (just think of the "potable" water tanks and what´s growing in them!).
F4f3a From United Kingdom, joined Jul 2004, 246 posts, RR: 0 Reply 21, posted (9 years 4 months 2 days 20 hours ago) and read 2087 times:
Getting the humidity isnt much of a problem as far as I can see but I believe that the pressure is three times that of current pressurised a/c. The only way they can get the strength in the structure is by using a composite structure.
Dl021 From United States of America, joined May 2004, 11443 posts, RR: 78 Reply 22, posted (9 years 4 months 2 days 18 hours ago) and read 2033 times:
The humidity and pressurization issues are not related technically. The two issues are comfort related, but the pressurization is designed to create a more comfortable cabin pressure for the average traveller who experiences swollen feet, headaches and other ailments in airplanes currently due to the cabins being pressurized to around 6-7000 ft. By bringing pressure up to levels found at 3500 or so feet the passengers will experience fewer ill effects. The humidity is being raised in order to elevate passenger comfort with dried eyes, noses and throats. It wil lreduce dehydration on longer flights as well as fatigue and other symptoms currently found after long distance travel. They have not yet been able to increase humidity levels in aircraft because of corrosion issues, among others, that will be less concerning with the composite structure.