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How're They Gonna Flight-test 7E7 Engines?  
User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4973 times:

DfwRevolution got me thinking about this...

...since these engines will be nigh-bleedless, and no other aircraft currently can utilize such a system: how will GE/RR flight-test the new 7E7 engines??




31 replies: All unread, showing first 25:
 
User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 1, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4758 times:

On a 747 testbed aircraft such as GE operate. As long as bleed air from the other engines is available it's not a problem.

Rolls will probably make their own arrangements, but in the past have used anything from the 747 prototype to a RAF VC10!

I somehow don't think the A340 testbed aircraft will be available this time....  Wink/being sarcastic

[Edited 2004-06-18 03:48:29]

User currently offlineDfwRevolution From United States of America, joined Jan 2010, 984 posts, RR: 51
Reply 2, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4738 times:

I'd like to know how I inspired such thought, as you've stupified me as well...  Smile/happy/getting dizzy

I guess GE will just use the 747 engine testbed. That aircraft has 3 other engines off of which to divert bleed-air, and all that must be tested is the electrical output of the engine right? The single GENEX will probably juice out more voltage than the other three engines combined, but that's what the 7E7 needs.


User currently offlineBoeingBus From United States of America, joined May 2004, 1597 posts, RR: 18
Reply 3, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4728 times:

But I can see where he is coming from... never thought of that...

But agree it would have to be a modified 4 engine plane like a 747 that would allow all the pneumatic controls to be powered on 2 classic engines and the other 2 would be 7E7 test engines.



Airbus or Boeing - it's all good to me!
User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 4, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4719 times:

Have you seen the pictures of the GE testbed with the GE90 fitted?


View Large View Medium

Photo © Je89 W.



That's a great picture for getting the scale of the GE90 against existing 747 engines

But agree it would have to be a modified 4 engine plane like a 747 that would allow all the pneumatic controls to be powered on 2 classic engines and the other 2 would be 7E7 test engines.

The testbed would generally only carry one test engine in case of a fault developing with both experimental engines. That's why a 747 testbed would have three standard units, to ensure safe operation.

[Edited 2004-06-18 03:55:59]

User currently offlinePlanemaker From Tuvalu, joined Aug 2003, 6246 posts, RR: 34
Reply 5, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4718 times:

And don't forget that for part of the flight regime they at least still have the APU available.


Nationalism is an infantile disease. It is the measles of mankind. - A. Einstein
User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 6, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4691 times:

To add to this subject...

...I'm curious as to how Boeing will test the various associated systems (that will sustain human life sans engine-bleed) in an actual flight?


User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 7, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4669 times:

I'd like to know how I inspired such thought, as you've stupified me as well...


Your last reply on this thread:
http://www.airliners.net/discussions/general_aviation/read.main/1615440/


User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 8, posted (10 years 4 months 1 week 3 days 7 hours ago) and read 4657 times:

...I'm curious as to how Boeing will test the various associated systems (that will sustain human life sans engine-bleed) in an actual flight?

Probably on the 7E7 prototype, with the test crew outfitted with breathing apparatus.

They could also adapt one or two of their in-house aircraft to test out certain components before the prototype is assembled. The only systems which will need to be tested are pressurisation and heating components, and they do have experience in non-bleed-air pressurisation from years ago as well.

Early 707s were not pressurised using bleed air. They had separate compressor assemblies.


User currently offlineDfwRevolution From United States of America, joined Jan 2010, 984 posts, RR: 51
Reply 9, posted (10 years 4 months 1 week 3 days 6 hours ago) and read 4627 times:

Your last reply on this thread

Lol.. I'll be damned.. anyway this is an interesting line of thought you have raised. But don't think I deserve credit for triggering it  Laugh out loud

...I'm curious as to how Boeing will test the various associated systems (that will sustain human life sans engine-bleed) in an actual flight?

Most likely through a combination of ground testing, testbed testing, and 7E7 certification. Boeing can test the enviornmental system on the ground, test the engine on the 747 testbed, then certify the two together on the actaul airframe.

Given the accuracy of computer simulation and that new versions of CATA allow Boeing to simulate system interaction, and with test results from both the engines and enviornmental systems in hand, Boeing should have a good idea of how the system will work far before roll-out. Then a rigerous certification regimine, Boeing should be able to prove the system.

The bleedless systems of the 7E7 will definitly be one of the most challenging aspects of 7E7 development. An analogy might be drawn between the 777 and ETOPS development and the 7E7 and bleedless development.

Probably on the 7E7 prototype, with the test crew outfitted with breathing apparatus.

Well if they need breathing devices, other than just out of precaution, Boeing might have some certification issues to work out...


User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 10, posted (10 years 4 months 1 week 3 days 6 hours ago) and read 4607 times:

Well if they need breathing devices, other than just out of precaution, Boeing might have some certification issues to work out...

Out of precaution. Boeing are notoriously conservative when it comes to testing.

Which is no bad thing, and why their products have the reputation they do.


User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 11, posted (10 years 4 months 1 week 3 days 6 hours ago) and read 4567 times:

new versions of CATA

CATIA  Big grin




An analogy might be drawn between the 777 and ETOPS development and the 7E7 and bleedless development.

Understood, but not so sure they're in the same magnitude.

I mean, ETOPS180 was being done before the 777's EIS. Bleedless technology to this degree has never been opped in pax transport before.

...perhaps when 777s start opping ETOPS240/330 will the analogy be more accurate  Big grin  Big thumbs up


User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 12, posted (10 years 4 months 1 week 3 days 6 hours ago) and read 4543 times:

I can't see bleedless being a major issue.

In the tradition of redundancy, there will be duplication of systems. It's just a case of providing electrical compressors and heating elements.

Hardly bleeding edge technology (ouch!)

Please feel free to shoot me for that one.... Big grin


User currently offlineA380900 From France, joined Dec 2003, 1116 posts, RR: 1
Reply 13, posted (10 years 4 months 1 week 3 days 4 hours ago) and read 4435 times:

The test engine need not be compatible with the remaining three. As Airbus points out about the Trent 900 testbed, it works with 5000 psi systems whereas the three other engines work with traditional 3000psi.

They have the entire empty aircraft to create a setting which makes the new engine working although it is different from the rest. Not a big challenge in my view.


User currently offlineVorticity From United States of America, joined May 2004, 337 posts, RR: 5
Reply 14, posted (10 years 4 months 1 week 3 days 3 hours ago) and read 4409 times:

It seems for the 777 program, they tested their Trent 800 on a Boeing 747 testbed. I found the information burried at the bottom of this webpage.

http://www.bcctc.ca/britjets.html

Not sure if that was a Boeing owned testbed, or what.



Thermodynamics and english units don't mix...
User currently offlineC130HERCULES From Trinidad and Tobago, joined Jun 2004, 77 posts, RR: 0
Reply 15, posted (10 years 4 months 1 week 2 days 19 hours ago) and read 4255 times:

That pic of the GE-115B on the 747 really gives the a/c some scale and simply dwarfs the other PW powerplants. What a blower that is.  Wow!


Vacation - ''Time wasted between two flights''
User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 16, posted (10 years 4 months 1 week 2 days 17 hours ago) and read 4133 times:

It seems for the 777 program, they tested their Trent 800 on a Boeing 747 testbed.

They used the prototype 747. It had, until recently at least, stickers on the forward fuselage showing that it had been used in the Trent 800 trials

When Rolls flight tested the first RB211 engine, they used a VC10 with 2 engines removed. Unfortunately that aircraft had to be written off as the imbalance twisted the airframe out of shape!

[Edited 2004-06-18 18:26:24]

User currently offlineFTOHIST From United States of America, joined Mar 2004, 73 posts, RR: 0
Reply 17, posted (10 years 4 months 1 week 2 days 16 hours ago) and read 4112 times:

It'll be tested in the #2 position, just like all the other test engines (with the exception of the CF34-8 in the ferry position, of course). Look for some MAJOR mods to the existing electrical load simulation system, which may include adding some fairly large bumps to the fuselage. I'd say it will be about the most ambitious flight test program seen on that airplane, and probably its last before retirement, since it can't carry a more powerful GE90 than the -115B.

User currently offlineVorticity From United States of America, joined May 2004, 337 posts, RR: 5
Reply 18, posted (10 years 4 months 1 week 2 days 16 hours ago) and read 4051 times:

They used the prototype 747. It had, until recently at least, stickers on the forward fuselage showing that it had been used in the Trent 800 trials

Hmm, last I saw that plane was in 2000, it was sitting next to a parking lot of Boeing Field, got a cool picture of my car with the 747 as a backdrop. I think it had all 4 engines off. I'm not sure if it's in flying condition anymore or not.

Unfortunately that aircraft had to be written off as the imbalance twisted the airframe out of shape!

 Big thumbs up whoops



Thermodynamics and english units don't mix...
User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 19, posted (10 years 4 months 1 week 2 days 15 hours ago) and read 4004 times:

Hmm, last I saw that plane was in 2000, it was sitting next to a parking lot of Boeing Field, got a cool picture of my car with the 747 as a backdrop. I think it had all 4 engines off. I'm not sure if it's in flying condition anymore or not.

It'll eventually be fully restored and parked undercover. There are plans to extend the museum at Boeing Field to bring it and the 727/737/Concorde etc into a new building.

There are some pictures of the RB211 test bed and more info here

http://www.vc10.net/History/Individual/XR809.html


User currently offlineCaetravlr From United States of America, joined Oct 2000, 909 posts, RR: 1
Reply 20, posted (10 years 4 months 1 week 2 days 15 hours ago) and read 3845 times:

Is any of the technology being used for the bleedless systems on the 7E7 available from any military experience that they may have? I know that a lot of their planned use for composites has a military background, but I was wondering about any of the new power systems they are planning? I wouldn't guess that it would, but it would be interesting to know.


A woman drove me to drink and I didn't have the decency to thank her. - W.C. Fields
User currently offlineCXA340 From United States of America, joined May 2004, 51 posts, RR: 1
Reply 21, posted (10 years 4 months 1 week 2 days 13 hours ago) and read 3523 times:

Excuse my ignorance...but what exactly is the difference with the new 7E7 engines compared with other models? I realize some of the basic engineering differences Boeing has talked about, but why make the engine completely bleedless? Will this mean a different way of starting the engine? And then, to follow up on a previous post, then would this mean entirely new systems for the interior since they will not be bleeding air off of the engines? Will this plane be more electrical in nature than mechanical?

User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 22, posted (10 years 4 months 1 week 2 days 13 hours ago) and read 3515 times:

but why make the engine completely bleedless?

Because of the same word you're going to hear associated with the 7E7 throughout its "life"---
EFFICIENCY


User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 23, posted (10 years 4 months 1 week 2 days 13 hours ago) and read 3444 times:

Electrical systems are more efficient than compressed air systems.

There is a weight saving as well as increased flexibility on what machinery goes where. Complex pipe and hose assemblies from the engines are eliminated.


User currently offlineCaetravlr From United States of America, joined Oct 2000, 909 posts, RR: 1
Reply 24, posted (10 years 4 months 1 week 2 days 13 hours ago) and read 3426 times:

Based on what WhiteHatter says, then not only will the plane weigh less, but it will also be more efficient, because (if I understand this correctly), that bleed air that is sucked off the engines takes away from the actual thrust that is being used to propel the aircraft. Is that right? This would mean that the engines are more efficiently propelling the jet.


A woman drove me to drink and I didn't have the decency to thank her. - W.C. Fields
25 ConcordeBoy : This would mean that the engines are more efficiently propelling the jet. Correct, among other things
26 Okie : Look for some MAJOR mods to the existing electrical load simulation system, which may include adding some fairly large bumps to the fuselage General E
27 Phollingsworth : Look for some MAJOR mods to the existing electrical load simulation system, which may include adding some fairly large bumps to the fuselage General E
28 Blackbird1331 : What the hell was it bleeding? Throw it it on a 757 and get it done with.
29 Alessandro : If they would like to be on the extra safe side they could use the AN-225 and only replace one of six engines....
30 Vorticity : What the hell was it bleeding? Throw it it on a 757 and get it done with. Probably can't fly the 757 on only one certified good engine.
31 FTOHIST : Yeah, that's what the airplane is doing in HAECO right now-having "GE Transportation" painted on it instead of "GE Aircraft Engines". So, now it can a
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