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STT757
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787 Engine Question

Tue Aug 15, 2006 6:04 am

I remember reading that they were thinking about allowing the 787 to be able to switch engines relatively easily, from RR to GE and vice versa for instance.

Has this been incorporated into the final design, to allow carriers to switch engines on 787s.

For instance lets say airline A which operates a fleet of GE powered 787s acquires Airline B which operates a fleet of RR powere 787s, will they be able to conform their fleet to a single engine type?
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cobra27
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RE: 787 Engine Question

Tue Aug 15, 2006 6:09 am

Yes, there should be no complications. Change engine software and isntall new engines and that is preety much it. The plane will have a little different performances
 
RichardPrice
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RE: 787 Engine Question

Tue Aug 15, 2006 6:11 am

No, it wasnt a case of being able to change engines easily as that would involve a significant amount of other changes such as the fuel management systems, pumps et al in the entire system (and maybe a recertification of that individual aircraft, anyone clarify?).

What was done, however, was the incorporation of a common pylon and structure system, allowing for reduced costs on Boeings part - less things to design and test. Boeht GE and RR hang their engines from the same pylon, whereas on earlier designs they had their own pylons tailored to their engines.

I also think theres only one inlet cowling on the 787 engines, again reducing design complexity.
 
PolymerPlane
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RE: 787 Engine Question

Tue Aug 15, 2006 6:23 am

Quoting RichardPrice (Reply 2):
No, it wasnt a case of being able to change engines easily as that would involve a significant amount of other changes such as the fuel management systems, pumps et al in the entire system (and maybe a recertification of that individual aircraft, anyone clarify?).

I remember in the early days of B787, boeing stated that engine change between RR and GE will take only 1 day or so. Boeing's point back then was that both engine will have a common mounting design, and since it's bleedless, the integration is easier. I believe they said that the plane needed to be reprogrammed though. I do not know whether in its evolution, this ability has changed or not.

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deltaguy767
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RE: 787 Engine Question

Tue Aug 15, 2006 6:24 am

What is the main difference between the to engines besides the obvious difference of brands? Does one have a better range than the other, or does one have better power etc? It's good to see that Boeing can simplify the design of the engine pylon/cowling with the engine-makers' cooperation thereby reducing cost and allowing the aircraft to come online faster. We all know that delays of a long-awaited aircraft can do for PR.  sarcastic 

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DeltaGuy676
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DfwRevolution
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RE: 787 Engine Question

Tue Aug 15, 2006 6:30 am

Quoting Cobra27 (Reply 1):
Yes, there should be no complications. Change engine software and isntall new engines and that is preety much it.

The latest information indicates that an engine change will fit within a standard maintenance down period.

Keep in mind that Boeing initially advertized the capability to change engine types "over night" in a single business day. So it isn't quite as easy as first promised, but still a practical feature for airlines to consider.

Quoting RichardPrice (Reply 2):
Boeht GE and RR hang their engines from the same pylon, whereas on earlier designs they had their own pylons tailored to their engines.

ASAIK, the pylon isn't 100% common. They are very simmilar, but the pylon must be changed with the engine as there are slight variances between the two powerplants.

That's why the conversion time was revised to a longer period.
 
roseflyer
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RE: 787 Engine Question

Tue Aug 15, 2006 6:35 am

Quoting DeltaGuy767 (Reply 4):
What is the main difference between the to engines besides the obvious difference of brands? Does one have a better range than the other, or does one have better power etc? It's good to see that Boeing can simplify the design of the engine pylon/cowling with the engine-makers' cooperation thereby reducing cost and allowing the aircraft to come online faster. We all know that delays of a long-awaited aircraft can do for PR.

Well they are quite a bit different. I know more specifics about the Trent 1000, but the engines are definitely designed differently. Yes they have the same 5 components (fan, compressor, combustion chamber, turbine and exhaust), but all the components are different. The gearboxes and fuel systems are separate. Every dimension on everything is different. They have the same components, but they are designed by completely different engineers and have their different tradeoffs. Expect different fuel efficiencies, varying range, varying thrust, varying optimal altitudes of operation, and a ton of other things.
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STT757
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RE: 787 Engine Question

Tue Aug 15, 2006 10:37 am

So it's not something that can be done overnight, but it is something that can be done during a routine maintenance period and it's not cost for prohibitive for carriers?
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Geo772
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RE: 787 Engine Question

Tue Aug 15, 2006 7:11 pm

Quoting STT757 (Reply 7):
So it's not something that can be done overnight, but it is something that can be done during a routine maintenance period and it's not cost for prohibitive for carriers?

It is unlikely that many airlines will be changing their engine provider even if they buy a second hand fleet. The cost of doing so will be huge, an engine change on a 777 for instance can take in the region of 24 hours from start to finish and it is unlikely that the 787 will be much quicker. Couple the software cahnges and the fact that you have to change both engines at the same time and it becomes a little bit more complicated. However there is a time when it would be possible and that is during a major hanger check that lasts weeks rather than days.

A routine maintenance period can be defined as short a period as an hour to a couple of months in some cases. For instance you can do a Pre Departure Check in quite a short period of time - it is still classified as routine.
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