|Quoting Duce50boom (reply 3):|
is there a performance penalty by running the elec. generators and hydraulic pumps off of the engines?
|Quoting BOEING747400 (reply 11):|
Do bleedless engines offer any advantages over today's engines which are non-bleedless? If so, then what are they?
|Quoting PhilSquares (reply 2):|
On "bleedless" engines, these functions would be replaced by electric motors. The motors would provide the air necessary to run some or all of the above systems.
|Quoting Dl757md (reply 12):|
The electrical pneumatic systems that will replace bleed air systems will be much more efficient.
|Quoting 2H4 (reply 16):|
Considering how long jet engines have been in use, why has it taken this long for this technology to be utilized in airliners?
|Quoting Dl757md (reply 1):|
This is possible because the pneumatic system of the aircraft (787) uses electric components for heating, air conditioning, and pressurization.
|Quoting CRJ200Mechanic (reply 21):|
Is the 787 refered in the quote above. Is that the 7E7?
|Quoting HAWK21M (reply 14):|
Motors or Pumps
|Quoting Dl757md (Reply 12):|
The main advantage is efficiency. A lot of hot air is dumped overboard in the process of supplying pneumatic functions to an aircraft. This is wasted energy.
|Quoting Dl757md (Reply 1):|
A bleedless engine is one that doesn't supply air from the internal flow of the engine to the pneumatic system of the aircraft. All of the air entering a bleedless engine will be used to create thrust, excepting a small amount of air for internal cooling and engine stability. This is possible because the pneumatic system of the aircraft (787) uses electric components for heating, air conditioning, and pressurization.
|Quoting Lehpron (Reply 28):|
Hold up, that's it?! How exactly is that a big deal for 787 then? How much 'thrust' was lost before? Does this contribute to the Trent 1000's fuel efficiency?
|Quoting Sonic67 (Reply 30):|
Is the gearing in the gearbox the same as other engines and will the electric generator still be gear driven off the fan on the 787?
|Quoting Okie (Reply 31):|
I have not seen any diagrams of the new engines but I would guess you will see rare earth permanent magnets mounted in a hub on the N1 turbine
|Quoting Okie (Reply 15):|
In terms of efficiency,
The least is compressed air
The next would be hydraulic
The highest would be electric
|Quoting Dl757md (Reply 32):|
I haven't seen any diagrams on the engine either. AFAIK all generators are mounted to the accessory gearbox which in a dual spool engine is driven by the SA de CV (Mexico)">N2 section
|Quoting HAWK21M (Reply 36):|
Has there been any Sucessfull Aircraft with Bleedless Engines in the past.
|Quoting IFIXCF6 (Reply 10):|
|Quoting NDSchu777 (Reply 37):|
From what I have heard the Starter/Generators will be mounted to the Accessory Gearbox of the engine and extract power the traditional way.
I can see where having the generator directly mounted on the spool would be efficient since you have no losses through a gearbox. However, the big negative I see is that the generator would be deep within the engine and inaccessable. I'm sure the generator is a very complicated unit and if you had a generator failure, it would not be replaceable on-wing, and would require the entire engine to be changed and a shop visit for repair. Mounting the generator on the gearbox makes it a line replaceable unit and if that component were to fail, it would be easy to just remove and replace and dispatch the airplane.
I can't speak for the engineers designing the engine, but that's why I think they're mounting the Starter/Generators on the AGB.
|Quoting Klaus (Reply 45):|
But only if the core is already at its limit, right? Unless it was for that, why burden the pilot with a loss of net thrust to worry about?
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