But I wanted to take a moment catch up on some other news. We just wrapped up a series of tests on a 787 Dreamliner fuselage barrel. And the tests couldn’t have gone any better. When I allude to “take it to the limit,” like the old Eagles song, I’m not kidding.
Turns out the barrel did better than expected under a condition with more than two-and-a-half times the force of gravity - at 200% limit load.
The composite barrel is completely enveloped by the test rig equipment during the structural testing for the 787 Dreamliner in Everett.
In Everett, Boeing engineers have been putting the composite technology, design, and construction through a series of static stress testing scenarios beginning late last year. The tests were done on a Section 46 (mid-fuselage) barrel as part of Boeing’s certification efforts for the 787.
During stress tests, parts of the airplane are pushed, pulled, and twisted by hydraulic jacks. This series of tests concluded last week with what’s called “destruct sequences.”
The tests were incremental. First, they put the barrel to “limit load.” This is a test that simulates the most extreme conditions expected in the life of the airplane.
Then, they went even further – putting the barrel at 150% of limit load. This is called “ultimate load,” and it’s the level required for certification.
Well, turns out the barrel showed no signs of damage after these tests. So they pushed the barrel past what’s known as “ultimate load.” Well beyond ultimate load. It’s a destruct-condition, and as I mentioned, it’s beyond two and a half times the force of gravity. And obviously well above even the most extreme conditions an airplane would experience.
At this point, the team observed audible indications of damage but the piece did not reach the point of destruction - even at this extreme load.
An array of monitors and screens inside the “control room” provided the team with plenty to focus on as data and video images of the barrel were displayed during testing. You may notice in the bottom photo, team members sporting retro flattop haircuts, starched white shirts, narrow ties, and horn-rimmed glasses - it’s their way of honoring the history and contributions of their predecessors - the pioneers of their field.
You might be interested to know that the tests put the barrel through a variety of scenarios simulating both standard and extreme flight conditions:
- Maneuvers at two and a half times the force of gravity without structural failure
- Maneuvers at negative gravity forces
- Maneuvers to simulate abrupt elevator up and elevator down conditions
- Emergency landings
- Engine out response conditions
- Performance during normal loads with the presence of visible damage to the composite materials
- Emergency landing at six times the force of gravity
- Extreme maneuvers with unrestrained cargo
These tests are all essential to clearing the Dreamliner for first flight. Now, the next step for engineers is an extensive inspection of the barrel and a study of the test results in detail – with an eye toward optimizing the 787 design.
The 787 barrel testing team. They put in a lot of long hours – including over the holiday break – and did an exceptional job to achieve these test results.
We’re going to be doing some additional testing on the composite barrel section, to learn more for our own background. And then there will be additional static testing required, which we’ll do on a full airplane structure before first flight. That test airplane is in final assembly in the factory right now.