A 380 (Merged)

[Trash Hauler]

Ah yes, what a convoluted world IP and patents can be. The drug companies are very good at "varying" the design of a medication to claim a change to the patent and so prevent others using the compound. In their business it is hard to produce a medication that performs the same as a competitor without using the patented compounds and copyrighted IP.

Even if Boeing extend the patent through variation of the existing design it would not prevent Airbus now designigning a steerable body gear as long they ensure they do not use specific details of the Boeing designs which (presumably) would still be protected IP in the form of copyright.

[forget]

"What a convoluted world IP and patents can be". Not so, in this case. IF Boeing had a patent on steerable body gear then it would have lasted 20 years from the date of application, and is long expired. After expiry anyone can use it. IF Boeing has added a few widgets, to keep them ahead of the competition, the orirginal patent, less the widgets, is still useable by anyone. Also, I'd question the issue of "IP in the form of copyright". The detailed engineering drawings will be copyright, but Airbus ain't in the business of building cloned Boeing bogies.

I don't believe that the A-380 lacks steerable body gear because of a patent issue. On the other hand, I do believe it has a big problem because it doesn't have steerable body gear

Hmmm. Having just checked the US Patent Office, this may be the one.

United States Patent 5,242,131
Watts September 7, 1993
Steerable landing gear
Abstract
A six wheel, three axle, bogie type main landing gear for an airplane is retractable as a unit and is provided with a rearward set of wheels or a forward set of wheels that is steerable with respect to the non-rotatable bogie beam. The set of wheels turns in response to steering of the nose wheel past a given angle. A wheel assembly is mounted for rotation with respect to a vertical shaft supported by a fork extending longitudinally of the beam, and a pair of hydraulic cylinders turns the wheel axles with respect to the beam.

Inventors: Watts; John (Redmond, WA)
Assignee: The Boeing Company (Seattle, WA)
Appl. No.: 865066
Filed: April 8, 1992

[Algy]

That landing gear story

...is here.

[forget]

So who convinced me that the A-380 doesn't have steerable gear.
Moral - Don't believe everything you read

[Trash Hauler]

I know the article linked above claims steerable gear however from what I have read (he says this digging in the grey matter for site he read it on) it is passive steering. The aft pair of wheels on the tripple bogie can castor when "unlocked" rather than be actively steered.

TH

*******************

See my next post (#20) for correction of duff gen above.

[forget]

So - on a push back the castoring wheels will be locked up. Heavy aircraft, tight turns, scrubbing tyres, - problems perchance? What happened to those photographs of a ripped up taxiway?

[Trash Hauler]

Having stretched the grey matter I have found the text of the article on my PC and it clearly says the main gear is steerable.

Sorry about the duff gen in my previous post. The article is below in full:

********************************

Air Transport

Airbus A380 Gear Put Through Drills

Aviation Week & Space Technology

07/25/2005, page 42

Michael A. Dornheim
Los Angeles
Robert Wall
Paris

A380 tires damage airport surface during 'abusive' turn test

Gear Concerns

Airbus is being forced to respond to Internet-circulated pictures of A380 tow tests, which show the landing gear carving grooves in the asphalt during turns sharper than normal limits. Reaction pushed the company to issue a letter to "airline focal points" on July 19.

Officials at Airbus and Goodrich, which engineered and builds the main landing gear, insist the results validate their design and they do not plan any changes. "Although spectacular for the non-specialist, actual deformations are not as high as on some other aircraft," Airbus wrote to the airlines. "Preliminary results confirm the design values of loads and deformations."

But while they are happy with the gear, others--such as airport operators--see the torn tarmac and wonder what will happen to their property. Some want more information, such as how strong the damaged asphalt was.

The June 25 tow tests at Toulouse were intended to stress the landing gear during "abusive cases" outside normal operation, Airbus says. During the trials, the gross weight was 546 metric tons (1,204,000 lb.); maximum takeoff weight for the aircraft is 560 tons. The tests consisted of "towing and pushback maneuvers at high weight, with various nose-landing-gear steering angles ranging from typical operational values up to extreme cases, close to bottoming of steering actuators, beyond the allowed towing/pushback limits," Airbus says.

Maximum steering angle for the A380 during towing will be restricted to a standard 60 deg., Airbus says. The tests were performed at 60 deg. and higher, reaching a maximum of 72 deg.

"Given the gear deformation buildup, no truck driver would ever bring the aircraft to the extreme steering angles achieved during this particular loads testing," Airbus says.

The A380 has four main landing gear, two on the body with six-wheel trucks and two on the wing with four-wheel trucks. The wing gear are forward of the body gear. On an aircraft with a simpler single-axle main landing gear, the axes of the nosewheel and the main wheels intersect at the center of the turning radius. But multiple main gear axles form parallel lines that can't intersect at the turning center, and some of the tires have to scrub laterally in a turn. The sharper the turn, the more they scrub. The Boeing 747 alleviates this problem by steering the body gear at low speeds so the axes point toward a common turning center, which reduces scrubbing.

THE ENTIRE A380 body gear doesn't steer, but the aft axle does steer on the six-wheel trucks. If the body steering mechanism is inoperative, the A380 can be dispatched with the wheels aligned and locked. The wing gear do not steer at all. In these photos, it is the wing gear that are scrubbing. The tests were the first in a series to check A380 ground handling. In August-September, Airbus plans to assess minimum turn radius at heavy weight and taxiing the aircraft with engines running. U-turns are also on the to-do list.

Airbus officials have begun trying to explain the situation, saying the tests marked a positive step in verifying that the A380 can taxi using FAA Design Group V or ICAO Code E runway/taxiway systems--a standard measure for those surfaces.

FOR THE JUNE 25 TEST, body wheel steering was deactivated. The aircraft was near its maximum weight, with an aft center of gravity, to represent a worst-case condition. The test procedure consisted in towing/pushing the aircraft out and into a turn. When the turn radius was stabilized, the aircraft was stopped, and pictures of the landing gear were taken.

Airbus officials note that given the roughly 90F temperature on the day of the test, and the fact that the aircraft was turned beyond set limits, "it is not abnormal to have some local deterioration of the asphalt." But one airport official quipped: "Ninety degrees? Is that all?"

Three tires were replaced after the test. This wasn't mandatory, Airbus says, but helped with the flight test schedule.

Airbus expects the A380 to be able to perform U-turns in a similar or smaller space than the A340-600 due to its shorter wheelbase. Moreover, the company points out that with 20 main landing gear wheels, the per-wheel weight on the A380 is lower than Boeing's 777-300ER.

[PAXboy]

From the Flight article mentioned above:

He says the build-up in outstanding work resulted from the policy last year to ship subassemblies to Toulouse incomplete, rather than hold them back and cause a bottleneck. "As each milestone in the build process was reached, if the required work had not been finished then the assemblies were delivered to the final assembly line uncompleted to avoid slowing the production rate," he says.

That is standard practice for any company these days. They always want to show that they are on target, even if they are not. It is unfortunate that investors and managers no longer have the confidence to make the customer wait until it is ready. This is one of the main downsides to strong competition. A simple alternative example of this problem is Microsoft, who have made it (almost) part of the development process to release software very early and get the customer to do much of the testing, hence the stricture never to buy the first release of anything.

The problem of photographs being aired out of context is a singularly modern one. People know that money is to be made from these photographs and the explanation is always running behind. This is most unfortuante and - in this instance - Airbus have my sympathy. For having shipped assemblies that are not yet complete, they do not.

[misd-agin]

The comments are related to the body gear and if it steers or castors. Two posts prior the article states that the taxiway damage came from the wing gear. Might be a completely different problem.

[forget]

[tilewood]

Forget

Your's is the most sensible comment anyone has made all week!!

[TSR2]

Must have been leaning damned hard !!!!!!

[forget]

Being mildly curious as to how the Boeing 747-8 competes with the A-380 I took a look at the Seattle site. Here's B's condensed comparisons. No wonder heads have rolled in Toulouse!

---------------
This latest family of the 747 jetliners meets airline requirements for a passenger airplane that serves the 400- to 500-seat market between the 555-seat Airbus A380 and the 365-seat Boeing 777-300 Extended Range airplanes, and a freighter that continues the leadership of the 747 Freighter family in the world cargo market.

The 747-8 Intercontinental is more than 12 percent lighter per seat than the A380, and consumes 11 percent less fuel per passenger. That translates into a trip-cost reduction of 22 percent and a seat-mile cost reduction of more than 4 percent compared to the A380.

The 747-8 is the only large airplane that fits today's airport infrastructure, giving airlines the flexibility to fly to more destinations. The 747-8 will build on the current 747's capability to fly into most airports worldwide, using the same pilot type ratings, services and most ground support equipment. With a range of over 14,815 km (8,000 nmi), the 747-8 Intercontinental can connect nearly any major city pair in the world.

The 747-8 Intercontinental is 11 percent more fuel efficient than the A380, and offers guaranteed QC2 departures.

The 747-8 Freighter's empty weight is 86 tonnes (95 tons) lighter than the A380 freighter. This results in a 25 percent lower fuel burn per ton, which translates into 20 percent lower trip costs and 23 percent lower ton-mile costs than the A380F.

[27/09]

According to him there is no such problem whatsoever.
The A380 can operate out of any airport which can
handle a 747.

I have seen this statement before, why then are airports that currently handle the 747 upgrading runways and taxiways and saying they are preparing for the A380?

[PAXboy]

forget thanks for the advertising blurb from Mr Bojangles ... Let us not forget that, once they actually build the thing, they may find that it is not all as they planned! In the same way that Airbus are finding their new baby is heavier than they planned, Boeing may find that:-
The 747-8 Intercontinental is not more than 12 percent lighter per seat than the A380, and consumes 11 6 percent less fuel per passenger.

I have no doubt that the 748i will sell well, as will the A380 but marketing blurbs about a machine that is still on paper are always good for a laugh. No need to tell me that the machine already exists and, therefore, is not paper - since it is not yet built, then it is paper. The fact that it may have a fine heritage falls away when they are going to have to use many new materials in order to make it as light as they say it will be. Actually, they are saying that the 748i is lighter than the A380 when they should be saying that it will be lighter. But salesman are never one to let grammar get in the way of a sale!
__________________
"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different."
Kurt Vonnegut, Jr.

[Volume]

The 747-8 Intercontinental is more than 12 percent lighter per seat than the A380

Even if this statement would be an engineering statement, and no marketing statement (called lie before political correctness became popular), it is still half of the truth.
Of course a structure designed and certified per 1960s rules is much lighter than a modern one. Different crashworthiness requirements, damage tolerant structure, larger rapid decompression hole size, different uncontained engine failure rules etc. costs weight and gains safety. Of course a 1960s Renault 4 is lighter per passenger seat than a 2006 Renault Megane, but would you buy one today, if you could ? Even if it would be equiped with a 21st century fuel economic engine and tinted glass windows ?

[Hunter58]

Oh, of course I would buy the Renault 4 (no tinted Windows please), but not for it's new engine but for the nostalgia involved...

I am just not sure that the nostalgia argument would effectively work for an aircraft...

[bekolblockage]

I think Volume's analogy is quite a good one. Watch the kilos pile on when the SMS requirements start to bite.

[Taildragger67]

"designed and certified in the 1960s"...

I think the 744 was certified as a new type (not a variant) due to the completely new wing, avionics, etc. and incorporating the the s.41 lessons, etc. whilst the 744ER was a variant of the 744.

If that's the case, then surely the 748, with new wing, engines fuselage stretch plugs, new materials and structures in critical places, etc. will also have to be certified as a new type?

My point being that whilst the overall shape might be retained (a deliberate decision, Boeing having done consumer studies to show that it is a design which is recognised and trusted by the consuming public, hence incorporates a large element of goodwill), the actual stuff under the skin will be pretty well all new.

Given that it will be first-flying in the 21st century, I'd suggest it will have to meet 21st century requirements for a new type in areas such as "... crashworthiness requirements, damage tolerant structure, larger rapid decompression hole size, different uncontained engine failure rules etc."

How many of you own a Porsche 911? Get online and Google-up a 911 family tree. You can trace the shape back to the 956 but no-one in their right mind would say they're the same underneath. But the punters recognise the shape as a Porsche so that's what the manufacturers have stuck with. The 911 of 2006 has a similar look (a few aerodynamic changes, etc. - rather like a new wing!) to that of 1969 but they're different beasts. Same with the 747 family.

[lomapaseo]

"designed and certified in the 1960s"...

Not a very significant statement. The idea behind certification is to certify it safe today. New concepts need apply today's knowledge both in their design and certification. Old concepts which have seasoned experience under continued airworthiness review certainly have less questions to answer.