Electrical output of airliners?
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Electrical output of airliners?
Hi everyone,
I'm looking for some info regarding the electrical output of long-haul airliners (787, 777, 767, 747, A330, A380).
I am working on an economy seat design concept that will allow much greater recline while maintaining a 33 inch pitch, but I am unsure how to attack the mechanicals.
I know business and first seats have multiple electric motors but are unsure whether sufficient electrical power is available for hundreds of economy seats - even those designed to use low amounts of power.
I had been looking at bleed air pneumatics also, but this requires a separate compressor on a 787 as they have bleedless engines.
I'm also considering a user-powered system of levers and springs, but electric would be easier.
I've approached Boeing and Airbus who don't seem to want to help unless I have a name within each organisation. Technical spec sheets don't seem to list cabin electrical availability either.
any help appreciated
I'm looking for some info regarding the electrical output of long-haul airliners (787, 777, 767, 747, A330, A380).
I am working on an economy seat design concept that will allow much greater recline while maintaining a 33 inch pitch, but I am unsure how to attack the mechanicals.
I know business and first seats have multiple electric motors but are unsure whether sufficient electrical power is available for hundreds of economy seats - even those designed to use low amounts of power.
I had been looking at bleed air pneumatics also, but this requires a separate compressor on a 787 as they have bleedless engines.
I'm also considering a user-powered system of levers and springs, but electric would be easier.
I've approached Boeing and Airbus who don't seem to want to help unless I have a name within each organisation. Technical spec sheets don't seem to list cabin electrical availability either.
any help appreciated
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I am *always* sat behind someone who reclines their seat fully at TOC and only uprights it again when the crew tell them to on descent (and not always then...). It makes it really hard to read/eat/watch the screen/get in an out to visit the loo.
If you allow them to recline further, I'll be trapped with my chin on the seat in front for the whole flight!
If you want to improve comfort in cattle class, finding a way to increase the spacing would be good...
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HDRW - thanks for the reply
I'm glad you wrote that, because my design is aimed at preventing exactly the problem you describe.
As a passenger, you have a constant space that remains the same irrespective of the actions of the passenger in front of you, in fact, you will not be able to tell whether the seat in front is reclined or not.
I'm glad you wrote that, because my design is aimed at preventing exactly the problem you describe.
As a passenger, you have a constant space that remains the same irrespective of the actions of the passenger in front of you, in fact, you will not be able to tell whether the seat in front is reclined or not.
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747-400 has 4 engine driven generators of approx 90KVA = 360KVA
A380 has 4 engine driven generators of approx 150KVA = 600KVA
767 has 2 engine driven generators of approx 90KVA = 180KVA
Each aircraft can have 1 generator unserviceable under MEL so design elec output is vaguely based upon;
747-400, 3 x 90 = 270KVA
A380, 3 x 150 = 450KVA
767, 1 x 90 = 90KVA
All aircraft have a "load shedding" or priority system for elec usage.
I.E you can have lots and lots of power hungry seats, IFE, galleys, showers, internet, hairdryers, elec window shades etc, etc, etc, etc.
However, critical systems will always take priority over this crap when limited elec supply is available (I.E MEL of an generator) or during critical
flight phases. Examples are config changes such as flaps moving or gear in transit when elec hydraulic pumps come on, fuel jettison when lots of
heavy duty fuel pumps start up or engine failure when a generator is lost.
As you can imagine, these scenarios are basically take-off and landing when no-one is moving their seat, having a shower etc. All these nice to
have things are used during cruise and are a random demand not all used at the same time. So there is a "relative" abundance of power available
for your new design seat. Don't forget that all 'elec' seats must have designed in, manual overides to return the seat to the TTOL (Taxi,TakeOff,Landing)
position in case of elec supply not available.
Good Luck
A380 has 4 engine driven generators of approx 150KVA = 600KVA
767 has 2 engine driven generators of approx 90KVA = 180KVA
Each aircraft can have 1 generator unserviceable under MEL so design elec output is vaguely based upon;
747-400, 3 x 90 = 270KVA
A380, 3 x 150 = 450KVA
767, 1 x 90 = 90KVA
All aircraft have a "load shedding" or priority system for elec usage.
I.E you can have lots and lots of power hungry seats, IFE, galleys, showers, internet, hairdryers, elec window shades etc, etc, etc, etc.
However, critical systems will always take priority over this crap when limited elec supply is available (I.E MEL of an generator) or during critical
flight phases. Examples are config changes such as flaps moving or gear in transit when elec hydraulic pumps come on, fuel jettison when lots of
heavy duty fuel pumps start up or engine failure when a generator is lost.
As you can imagine, these scenarios are basically take-off and landing when no-one is moving their seat, having a shower etc. All these nice to
have things are used during cruise and are a random demand not all used at the same time. So there is a "relative" abundance of power available
for your new design seat. Don't forget that all 'elec' seats must have designed in, manual overides to return the seat to the TTOL (Taxi,TakeOff,Landing)
position in case of elec supply not available.
Good Luck
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HDRW - thanks for the reply
I'm glad you wrote that, because my design is aimed at preventing exactly the problem you describe.
As a passenger, you have a constant space that remains the same irrespective of the actions of the passenger in front of you, in fact, you will not be able to tell whether the seat in front is reclined or not.
I'm glad you wrote that, because my design is aimed at preventing exactly the problem you describe.
As a passenger, you have a constant space that remains the same irrespective of the actions of the passenger in front of you, in fact, you will not be able to tell whether the seat in front is reclined or not.
I cannot see how you can retain coach class passenger seating 'density', allow them to store carry-on bags 'under the seat in front' and allow a sliding recline. If you could do that the manufacturers Boeing and Airbus and the airlines would be beating a path to your door.
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Ian W - thank you for the info
I can't really go into the exact method by which I have configured the seating, but at present (prior to any extensive real-world prototyping) I think I have a way to satisfy all the requirements you describe - with the possible exception of being able to place a carry-on size bag beneath the seat in front. However, I don't think you can do that with current designs - especially of you are sitting in the centre-seat/s of three or four seat blocks.
You can get a decent size backpack etc under there (if you don't wish to recline fully) but not a standard international carry-on bag. I thought these were meant to go in the overhead bins?
It's good news that there is available power onboard most planes. I had read up on the electrical output of various engine types but had no idea how the power was used by onboard systems.
Coincidentally, I was reading about load-shedding recently - but with respect to the Apollo guidance computer, which I believe was one of the first vehicle systems to use it.
thanks again
I can't really go into the exact method by which I have configured the seating, but at present (prior to any extensive real-world prototyping) I think I have a way to satisfy all the requirements you describe - with the possible exception of being able to place a carry-on size bag beneath the seat in front. However, I don't think you can do that with current designs - especially of you are sitting in the centre-seat/s of three or four seat blocks.
You can get a decent size backpack etc under there (if you don't wish to recline fully) but not a standard international carry-on bag. I thought these were meant to go in the overhead bins?
It's good news that there is available power onboard most planes. I had read up on the electrical output of various engine types but had no idea how the power was used by onboard systems.
Coincidentally, I was reading about load-shedding recently - but with respect to the Apollo guidance computer, which I believe was one of the first vehicle systems to use it.
thanks again
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CX have (mechanically) reclining seats in economy where the seat back (shell) doesn't move but the seat still reclines. If you fly on one of our a/c you will be able to see it in action.
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be careful with your designs and consider not using electric motors to move the chair
so many problems that you may not have thought of including how to move chair in electrical problem, crash landing and loss of power, interference with pacemakers (ac motors), added weight and maintenance requirements.
you simply can't put 10 pounds of SUGAR (yeah right) in a 7 pound sack.
our airline installed a great idea in airline seats and within days the shortcomings of LINE ops made us remove the seats and replace them with the old ones...we lost money on that deal.
so many problems that you may not have thought of including how to move chair in electrical problem, crash landing and loss of power, interference with pacemakers (ac motors), added weight and maintenance requirements.
you simply can't put 10 pounds of SUGAR (yeah right) in a 7 pound sack.
our airline installed a great idea in airline seats and within days the shortcomings of LINE ops made us remove the seats and replace them with the old ones...we lost money on that deal.
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" economy" and "electric ajustment" are contradictory.
A self-contained ,mechanically -ajustable seat can be quickly removed or reconfigured, without the associated extra wiring-harness.
Consider worm/quadrant, Acme thread/split-nut , rack and pawl as three mechanisms that lend themselves to a rapid disengagement/reset as well as a slower,more progressive movement..
just my take on it, but the most important thing about a seat iscomfort
get that right and the range of fancy gimmicks ,hence the price, complexity and certification/maintenance costs can be reduced.
You cannot magic up space from nowhere . if it doesn't come from the space behind, it has to come from the "spare" space allocated to the seat's own occupant....that, in turn, creates a problem of access/egress for the pax between the seat in question and an obstruction (cabin-side of ajacent pax.)
A self-contained ,mechanically -ajustable seat can be quickly removed or reconfigured, without the associated extra wiring-harness.
Consider worm/quadrant, Acme thread/split-nut , rack and pawl as three mechanisms that lend themselves to a rapid disengagement/reset as well as a slower,more progressive movement..
just my take on it, but the most important thing about a seat iscomfort
get that right and the range of fancy gimmicks ,hence the price, complexity and certification/maintenance costs can be reduced.
You cannot magic up space from nowhere . if it doesn't come from the space behind, it has to come from the "spare" space allocated to the seat's own occupant....that, in turn, creates a problem of access/egress for the pax between the seat in question and an obstruction (cabin-side of ajacent pax.)
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I reckon it would be a great idea if the top of the seat back remained fixed and reclining was achieved by moving the bottom of the seat back forward.
This way anyone reclining their seat would stuff themselves into the seat in front and not upset the person behind.
This way anyone reclining their seat would stuff themselves into the seat in front and not upset the person behind.
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Pretty sure the IDG's are rated at 60KVA. The APU gen's are rated at 90KVA (different cooling).
I'm pretty sure you could be talking about the generators fitted to the 'classic' 747's whereby the generator was the same Part Num as the ones fitted to the APU yet on the main engine were driven by a seperate CSD (constant speed drive). Yes, there was less cooling air available in the cramped quarters under the engine cowls and output was approx 60KvA in this installation. APU had a dedicated cooling fan driven off gearbox to cool the gennies fitted up the back end.
Figures in post above are for the 747-400 with IDG'S fitted (CSD and generator all in one with dedicated oil cooling system). Same item is fitted to 767'S. Below is from the Maintenance Manual.
An integrated drive generator (IDG) is mounted on the aft face of the accessory gearbox at the 7 o’clock position. The IDG consists of a constant speed drive and a generator mounted side by side in a common housing. Other parts integral or mounted to the IDG are the scavenge filter, thermal relief valve, and pressure relief valve. The IDG converts the varing input speed of the engine into 115/200volt, 3-phase, 90 KVA, 400 ±5 Hz power. The IDG weighs approximately 120 pounds (54 kilograms).
.
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Mommus,
The electrical load of your idea might not be that big a deal...if you factor in diversity.
For example, on a 250 seat 787, how many people will be operating their seat motors simultaneously? Probably guess no more than around 20 or so. So you only need to allow capacity for 20 rather than 250...throw in some wriggle room, and you might say 30.
I'd be more concerned at the combined weight of all those motors and associated wiring...
The electrical load of your idea might not be that big a deal...if you factor in diversity.
For example, on a 250 seat 787, how many people will be operating their seat motors simultaneously? Probably guess no more than around 20 or so. So you only need to allow capacity for 20 rather than 250...throw in some wriggle room, and you might say 30.
I'd be more concerned at the combined weight of all those motors and associated wiring...
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Ref diversity, I wouldn't want to bet on what the load would be when the flight attendant tells the cabin to return seats to the upright position...
Lots of electrics equals extra unnecessary fire risk in my mind.
Lots of electrics equals extra unnecessary fire risk in my mind.
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VinRouge,
Good point...so we might need to add in some electronics to stagger any mass seat movements...or we let the cabin crew control that element in groups. "Passengers in row 25 will now be returned to the upright position!"...
Good point...so we might need to add in some electronics to stagger any mass seat movements...or we let the cabin crew control that element in groups. "Passengers in row 25 will now be returned to the upright position!"...
Last edited by NWSRG; 23rd Sep 2013 at 20:57.
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I don't think it will be hard to write some load-managing software that either denies certain users control of their seats or simply reduces the movement speed at times of high load.
At the moment I am working with a design that uses only one compact electric motor per seat. I am unaware of any case where an electric motor on a business or first class seat has caught fire.
At the moment I am working with a design that uses only one compact electric motor per seat. I am unaware of any case where an electric motor on a business or first class seat has caught fire.
Spanner Turner is correct - 747-400 has 4 x 90 KVA IDGs.
747-8 uses the same IDGs as the -400, but they are rated 96 KVA each for the -8 installation.
Most 767 are 2 x 90 KVA, although the Japanese AWACs 767s were 4 x 150 KVA (two per engine)
777 is 2 x 120 KVA, plus 2 x VSCF at (I think) 20 KVA
787 has 4 x 150 KVA (two per engine).
747-8 uses the same IDGs as the -400, but they are rated 96 KVA each for the -8 installation.
Most 767 are 2 x 90 KVA, although the Japanese AWACs 767s were 4 x 150 KVA (two per engine)
777 is 2 x 120 KVA, plus 2 x VSCF at (I think) 20 KVA
787 has 4 x 150 KVA (two per engine).
Last edited by tdracer; 24th Sep 2013 at 00:00.