Hawker From Australia, joined Aug 2004, 105 posts, RR: 0 Posted (11 years 2 weeks 4 days 18 hours ago) and read 4486 times:
I know very little about composite construction bit feel a little nervous about flying in such a plane. With metal it is possible to see cracks developing but are there any warning signs with composites? Have large composite sections been used previously in airliners, with the repeated pressurisation and landing cycles over a period of years, to demonstrate their durability?
Also all new airliners have teething problems but it seems that Boeing are taking a considerable risk with all the new technologies in the 787. If the plane has even minor technical problems which make it unreliable, won't Boeing be in serious trouble?
The A380 is an incremental technical advance, but is Boeing in the same position as De Havilland with the first Comet, which had fatigue problems which were outside the scope of all previous technical experience.
TrappedInMKG From United States of America, joined Dec 2007, 4 posts, RR: 0
Reply 3, posted (11 years 2 weeks 4 days 18 hours ago) and read 4429 times:
First of all, the tail of the A300 is composite, and that's a pretty big structure. If there were major problems with this, I would think we would have known by now. This also means that mechanics and certification authorities (the FAA) have at least some experience dealing with this sort of thing.
Second, as Starlion said, the aircraft has to be certified. That means that it will go through extremely rigorous testing before any passengers come anywhere near it. The intent of this period is to uncover any problems BEFORE they become especially dangerous. Here's hoping this process works the way it's supposed to.
Third, although it's natural, this kind of fear is symptomatic of a larger problem rampant on A.net, the thinking that airliner manufacturers, airlines, etc. don't know what they're doing and haven't put tremendous amounts of thoughts into things. If composites weren't safe, Boeing wouldn't be using them.
Pilotpip From United States of America, joined Sep 2003, 3176 posts, RR: 9
Reply 4, posted (11 years 2 weeks 4 days 16 hours ago) and read 4309 times:
Composites can also be laid in a manner that there are no stress points at critical junctions or can also be set to flex in specific ways while not fatiguing. In this way, it could be argued that composites are stronger, therefore safer for this application.
There are a number of airplanes out there that have used a composite fuselage already. The Raytheon Premere business jet is one of them. Composites have also seen much heavier usage in military aircraft for years so this isn't as simple as slide rules making the comet. Aircraft manufacturing isn't some sort of black art like it once was (unless your Burt Rutan). The major manufacturers have tweaked present designs to the point that a new leap is needed because they can't get much more out of what's there. This aircraft, like the 777 and A380 before it will "fly" thousands of times in computer simulations and every major issue will be addressed before the thing even lifts off the ground. If the A380 were developed today using advances that weren't there five or ten years ago it would likely incorporate much more composite material.
57AZ From United States of America, joined Nov 2004, 2586 posts, RR: 2
Reply 5, posted (11 years 2 weeks 4 days 16 hours ago) and read 4271 times:
From a risk management point of view, you will be much safer in the 787 than in an aluminum bird. The aircraft will be held to the same test standards as current aircraft. Properly bonded, composite components are much stronger than their aluminum counterparts. Composite parts have several layers that are baked together at high temperature-strong as steel when they come out of the oven and being nonmetallic, they don't have the problem of corrosion that aluminum has. Composite parts have been out there long enough that there are already established inspection protocols.
As for taking significant risk-sometimes you have to do that to stay alive. What if Boeing had thought that either the 707 or 747 designs were too risky? Boeing had considerable experiance with jet bombers and large aircraft that made them feel that techonoligically, both airplanes were possible. When it came to the sales end of the business, they looked at their estimates and took the leap of faith. Aversion to reasonable risk creates stagnation.
"When a man runs on railroads over half of his lifetime he is fit for nothing else-and at times he don't know that."
AR1300 From Argentina, joined Feb 2005, 1750 posts, RR: 2
Reply 6, posted (11 years 2 weeks 4 days 16 hours ago) and read 4262 times:
Quoting TrappedInMKG (Reply 3): First of all, the tail of the A300 is composite, and that's a pretty big structure. If there were major problems with this, I would think we would have known by now.
Ask AA or Air Transat about this.They know a lot about A300/10 and tails and how safe it is and stuff. (Those accidents had nothing to do with the material per se, if I'm not mistaking, they were due to the pilot's fault.At least with the AA one.)
PPVRA From Brazil, joined Nov 2004, 9105 posts, RR: 37
Reply 7, posted (11 years 2 weeks 4 days 15 hours ago) and read 4221 times:
Quoting Hawker (Thread starter): Have large composite sections been used previously in airliners, with the repeated pressurisation and landing cycles over a period of years, to demonstrate their durability?
The B-2, built by Boeing. Plus numerous other military aircraft make extensive use of these materials.
BTW, it's not really a "plastic," it's a fiber, much more than just a plastic. Think kevlar (although Boeing isn't using any kevlar), they bullet proof everything with it nowadays.
With the little I know about these materials, I would feel safer in a composite aircraft then in a metal one.
"If goods do not cross borders, soldiers will" - Frederic Bastiat
Milan320 From Canada, joined Jan 2005, 873 posts, RR: 10
Reply 8, posted (11 years 2 weeks 4 days 15 hours ago) and read 4187 times:
In that case, could someone englighten me on the apparent problems that the Mitsubishi built wing for the F-22, I believe, has had? I've read numerous times that cracks have been found in the composite wing, and it's Mitsubishi that's producing the wing for the 787 isn't it??
N766UA From United States of America, joined Jul 1999, 8736 posts, RR: 23
Reply 11, posted (11 years 2 weeks 4 days 8 hours ago) and read 3997 times:
Quoting TrappedInMKG (Reply 3): First of all, the tail of the A300 is composite, and that's a pretty big structure
I wouldn't use the A300 tail as a positive example, given 2 incidents in recent years which have brought up serious questions about that particular empenage. However, Boeing's got alot of experiance building airplanes. If they think composites have come of age and it's time to build a jetliner out of them, then I'm willing to bet my life it's 100% safe. Boeing won't go about gambling people's lives just to have an edge in marketing.