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787 High Blower Test Completed  
User currently offline777ER From New Zealand, joined Dec 2003, 12210 posts, RR: 18
Posted (6 years 3 weeks 2 days 21 hours ago) and read 9988 times:
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This just in via e-mail

Boeing successfully completed a high-pressure test, known as "high blow," on the 787 Dreamliner static test airframe at its Everett factory today. The test is one of three static tests that must be cleared prior to first flight. During the test, the airframe reached an internal pressure of 150 percent of the maximum levels expected to be seen in service - 14.9 lbs. per square inch (1.05 kilograms per centimeter) gauge (psig). It took nearly two hours to complete the test, as pressure was slowly increased to ensure the integrity of the airplane.

http://www.boeing.com/news/releases/2008/q3/080927a_nr.html

20 replies: All unread, jump to last
 
User currently offlineIflyKPDX From United States of America, joined Mar 2007, 287 posts, RR: 0
Reply 1, posted (6 years 3 weeks 2 days 21 hours ago) and read 9951 times:

Glad to hear it went well ! Anyone know what the other two tests are and when they're scheduled to happen?

[Edited 2008-09-27 16:26:52]


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User currently offlineAirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 24
Reply 2, posted (6 years 3 weeks 2 days 20 hours ago) and read 9726 times:



Quoting IflyKPDX (Reply 1):
Anyone know what the other two tests are and when they're scheduled to happen?

One of them should be the wing flex test, IIRC.



A Safe Flight Begins With Quality Maintenance On The Ground.
User currently offlinePygmalion From United States of America, joined Jun 2006, 966 posts, RR: 38
Reply 3, posted (6 years 3 weeks 2 days 20 hours ago) and read 9678 times:



Quoting AirframeAS (Reply 2):
One of them should be the wing flex test, IIRC.

The "ultimate load" wing test is last and not required for test flight. IIRC the tests needed prior to flight are maneuvering loads and gear loads. something like a 2G maneuver and a max TO speed stop, both are less than ultimate.


User currently offlineAirCanada014 From Canada, joined Oct 2005, 1513 posts, RR: 0
Reply 4, posted (6 years 3 weeks 2 days 18 hours ago) and read 9457 times:

So what is the 2nd static test before the ultimate load wing test?

User currently offlineSpeedbird2263 From Jamaica, joined Jul 2006, 470 posts, RR: 1
Reply 5, posted (6 years 3 weeks 2 days 17 hours ago) and read 9347 times:



Quoting 777ER (Thread starter):
During the test, the airframe reached an internal pressure of 150 percent of the maximum levels expected to be seen in service - 14.9 lbs. per square inch (1.05 kilograms per centimeter) gauge (psig). It took nearly two hours to complete the test, as pressure was slowly increased to ensure the integrity of the airplane.

Don't quite remember the exact number but isnt that close to atmospheric pressure exerted at sea level at the equator? Interesting thought  scratchchin 

As a side I remember seeing the video of that very same test performed on the 772, very interesting as it also gave the engineers a chance to fix things like door seals where there was a bit too much leakage.



Straight'n Up 'N Fly Right Son ;)
User currently offlineHawkerCamm From United Kingdom, joined Jul 2007, 405 posts, RR: 0
Reply 6, posted (6 years 3 weeks 2 days 12 hours ago) and read 8781 times:



Quoting IflyKPDX (Reply 1):
Anyone know what the other two tests are and when they're scheduled to happen?

I think they need to check Limit Load on the ground and in the air for the appropriate take-off weight before flight which will be steadily increased.


User currently offlineSpinaltap From New Zealand, joined Mar 2005, 440 posts, RR: 0
Reply 7, posted (6 years 3 weeks 2 days 10 hours ago) and read 8090 times:



Quoting Speedbird2263 (Reply 5):
Don't quite remember the exact number but isnt that close to atmospheric pressure exerted at sea level at the equator? Interesting thought

yes, but because it is a gauge pressure, this is a pressure in excess of the atmospheric pressure. The absolute pressure will thus be close to twice the atmospheric pressure.

14.9 psig (pounds per square inch gauge) = 1.01 atm (gauge)
so 14.9 psig = 2.01 atm (absolute)

[= 2.04 bar (abs.) = 204 kPa (abs.)]



"I get what they call a stipend, a stipend is like money but its such as small amount they don't really call it money"
User currently offline2175301 From United States of America, joined May 2007, 1074 posts, RR: 0
Reply 8, posted (6 years 3 weeks 2 days 10 hours ago) and read 8033 times:



Quoting Speedbird2263 (Reply 5):
Don't quite remember the exact number but isnt that close to atmospheric pressure exerted at sea level at the equator? Interesting thought

The clue for what pressure the test was done at is in the pressure designation: psig

There are two pressure designations:

1) psia: Pounds per Square Inch - Absolute (measured from zero pressure).

2) psig: Pounds per Square Inch - Gauge (pressure above whatever atmospheric pressure already exist).

You are correct in that 14.9 psig is numerically close to the 14.7 psia atmospheric pressure at sea level on a normal weather day (average barometric pressure due to weather effects); if you ignore the difference in the pressure designation. In reality 14.9 psig is probably somewhere in the range of 29.2 to 30 psia).

Notice the test was twice what the airframe would be expected to see in service. So that is essentially twice normal atmospheric pressure. Several minor variations for expected service could account for the use of 14.9 pisg instead of 14.7 psig. The key one that I can think of is just operating in a really nice weather day (high barometric pressure).


User currently offlineSpinalTap From New Zealand, joined Mar 2005, 440 posts, RR: 0
Reply 9, posted (6 years 3 weeks 2 days 7 hours ago) and read 7218 times:



Quoting 2175301 (Reply 8):
Notice the test was twice what the airframe would be expected to see in service. So that is essentially twice normal atmospheric pressure. Several minor variations for expected service could account for the use of 14.9 pisg instead of 14.7 psig. The key one that I can think of is just operating in a really nice weather day (high barometric pressure).

No, I don't think you are correct here. The test was only 150 % of the expected pressure difference. When the plane is flying at high altitude the pressure difference between the cabin and outside the plane is the important thing. As we know the 787 will be pressurised to maintain cabin pressure at 6000 ft rather than 8000 ft. This means a cabin pressure of approximately 81 kPa.* The service ceiling of the 787 is 43,000 ft at which the air pressure is about 16 kPa. The difference in air pressure at ceiling is thus 65 kPa.

150% of 65 kPa = 97.5 kPa = 0.96 atm

A further 0.05 atm buffer (to 1.01 atm) was probably used to take account of lower pressures due to weather conditions. (Note: low pressure systems will cause a higher pressure differential between the outside air and the cabin).

Thus to simulate the conditions at 43000 ft the plane at sea level needed to be pressured to a gauge pressure of 1.01 atm or an absolute pressure of 2.01 atm.

*Air pressures as a function of altitude were obtained from:
http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html



"I get what they call a stipend, a stipend is like money but its such as small amount they don't really call it money"
User currently offlineCAL764 From United States of America, joined May 2008, 377 posts, RR: 0
Reply 10, posted (6 years 3 weeks 2 days 5 hours ago) and read 6478 times:

Good news, indeed. I don't think anyone thought it wouldn't pass...


1. Fly to Win 2. Fund Future 3. Reliability 4. Work Together CO: Work Hard, Fly Right...
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 11, posted (6 years 3 weeks 2 days 4 hours ago) and read 5924 times:



Quoting IflyKPDX (Reply 1):
Anyone know what the other two tests are and when they're scheduled to happen?



Quoting IflyKPDX (Reply 1):
One of them should be the wing flex test, IIRC.

Definitely not...that's the last test they'll do.

Quoting AirCanada014 (Reply 4):
So what is the 2nd static test before the ultimate load wing test?

There are several thousand tests between now and ultimate wing load test...I'm not sure what you're getting at here.

Tom.


User currently offlineIflyKPDX From United States of America, joined Mar 2007, 287 posts, RR: 0
Reply 12, posted (6 years 3 weeks 2 days 4 hours ago) and read 5727 times:



Quoting Tdscanuck (Reply 11):

Quoting IflyKPDX (Reply 1):
One of them should be the wing flex test, IIRC.

Definitely not...that's the last test they'll do.

Wasn't me!



Airport Management - UND
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 13, posted (6 years 3 weeks 2 days 1 hour ago) and read 4634 times:



Quoting IflyKPDX (Reply 12):

Quoting Tdscanuck (Reply 11):

Quoting IflyKPDX (Reply 1):
One of them should be the wing flex test, IIRC.

Definitely not...that's the last test they'll do.

Wasn't me!

Sorry! Hit the wrong quote button.

Tom.


User currently offlineAirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 24
Reply 14, posted (6 years 3 weeks 1 day 23 hours ago) and read 3936 times:



Quoting Tdscanuck (Reply 11):
Quoting IflyKPDX (Reply 1):
One of them should be the wing flex test, IIRC.

Definitely not...that's the last test they'll do.



Quoting Tdscanuck (Reply 13):
Sorry! Hit the wrong quote button.

And it has already been said in Reply # 3, TDSCanuck.



A Safe Flight Begins With Quality Maintenance On The Ground.
User currently offlineJoeCanuck From Canada, joined Dec 2005, 5476 posts, RR: 30
Reply 15, posted (6 years 3 weeks 1 day 14 hours ago) and read 3006 times:



Quoting Spinaltap (Reply 7):

To put it in simpler terms, it's pressure differential...measuring the difference in pressure between inside and outside the hull. 14.7psi on both sides equals 'zero' for the test. Pumping another 14.7 into the fuse is what gives the pressure rating...or something like that.



What the...?
User currently offlineRussianJet From Belgium, joined Jul 2007, 7710 posts, RR: 21
Reply 16, posted (6 years 3 weeks 1 day 10 hours ago) and read 2776 times:

I'm bored. Just fly the damn plane already.


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User currently onlineStitch From United States of America, joined Jul 2005, 31097 posts, RR: 85
Reply 17, posted (6 years 3 weeks 1 day 6 hours ago) and read 2508 times:
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Quoting RussianJet (Reply 16):
I'm bored. Just fly the damn plane already.

A senior 787 engineer was anonymously quoted in a Seattle Times article this morning noting that ZA001 is just about ready to go. They need the IAM back to do some minor paint touch-up and other stuff and then she can start the testing program.


User currently offlineSpeedbird2263 From Jamaica, joined Jul 2006, 470 posts, RR: 1
Reply 18, posted (6 years 3 weeks 1 day 5 hours ago) and read 2381 times:



Quoting Spinaltap (Reply 7):



Quoting 2175301 (Reply 8):

'Preciate the clarification mates.  Smile I wasn't too far off in my thinking...and as for the pressure designations for all my A-level Physics that's the first Ive read about that. Either that or its been way too long.  silly 



Straight'n Up 'N Fly Right Son ;)
User currently offlineYYZatcboy From Canada, joined Apr 2005, 1089 posts, RR: 0
Reply 19, posted (6 years 3 weeks 1 day 4 hours ago) and read 2275 times:
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Do they have to do the MTOW RTO test before or can they do it after first flight?


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User currently offlineHawkerCamm From United Kingdom, joined Jul 2007, 405 posts, RR: 0
Reply 20, posted (6 years 3 weeks 1 day 1 hour ago) and read 2078 times:



Quoting YYZatcboy (Reply 19):
Do they have to do the MTOW RTO test before or can they do it after first flight?

They'll probably do some high speed taxi testing followed by a light weight RTO (with reverse thrust?) prior to first flight.

The MERTO (Max Energy Rejected Take-Off) will come much later. That test also carries the risk of damaging the aircraft therefore the aim should be for ZA001 to clearence the way for ZA002-4. ZA001 should be a heavily loads instrumented aircraft and together with the static test will progressive open the loads envelope for the following aircraft which will likely be tasked with different jobs e.g. Cruise Performance, Engine Performance, High Lift Configuration freeze (detailed slat and flap fine tuning), Take-Off performance, Landing Performance, Flooded Runway, Cabin Systems, Flight control law optimisation?, cold soak, Icing (with and without Anti-ice).

The 1st 10 give or take flights will be at light weights and tasked to prove the basic operation of the aircraft systems, Landing Gear & Slat/Flap retraction, Control surface operation, pressurisation, auto pilot, FTI, safe engine operation (temps, oil/fuel consumptions), basic measured structural air loads.

Any news regarding ZA002-4?


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