New electric aircraft propulsion unit
Thread Starter
Join Date: Sep 1999
Location: USA
Posts: 122
Likes: 0
Received 0 Likes
on
0 Posts
New electric aircraft propulsion unit
This looks interesting - an impressive power pack. The article says
"The combination of an electric motor with a combustion engine allows the use of a turbine that is not only much smaller than the current ones, but can be used with maximum efficiency during flight."
Anyone know how this works? How much electrical power is required and where could it be generated?
Siemens develops world-record electric motor for aircraft
"The combination of an electric motor with a combustion engine allows the use of a turbine that is not only much smaller than the current ones, but can be used with maximum efficiency during flight."
Anyone know how this works? How much electrical power is required and where could it be generated?
Siemens develops world-record electric motor for aircraft
Join Date: Jan 2014
Location: N5109.2W10.5
Posts: 720
Likes: 0
Received 0 Likes
on
0 Posts
Hi Groucho,
I guess it works by having a combustion engine that only needs to develop the power equivalent of MCT. The electric motor + battery + combustion engine would only need produce take off thrust for up to say 10 mins.
260 kW.
by the combustion engine.
See Rolls-Royce Marine Olympus - Wikipedia, the free encyclopedia
RR Gas turbine Olympus and Tyne engines are commonly used to generate electricity on ships.
I guess it works by having a combustion engine that only needs to develop the power equivalent of MCT. The electric motor + battery + combustion engine would only need produce take off thrust for up to say 10 mins.
How much electrical power is required
where could it be generated?
See Rolls-Royce Marine Olympus - Wikipedia, the free encyclopedia
RR Gas turbine Olympus and Tyne engines are commonly used to generate electricity on ships.
Turboprop
This could also replace the gearbox needed for a turboprop. Turbine/generator runs to produce the average power requirements at whatever speed is most efficient. A variable frequency drive takes this power, together with battery power and spins this motor at the prop's design speed. No gears needed.
Designers are also not constrained by the mechanical layouts of shaft/gearbox driven propellers. The turbine/generator(s) could be located in the wing box area with these motors out in the nacelles on the wings. There would be some aerodynamic improvements as well.
For a single turbine/generator failure, the remaining sources could still drive all the propellers (at reduced power) resulting in no yaw (and resulting correction).
Designers are also not constrained by the mechanical layouts of shaft/gearbox driven propellers. The turbine/generator(s) could be located in the wing box area with these motors out in the nacelles on the wings. There would be some aerodynamic improvements as well.
For a single turbine/generator failure, the remaining sources could still drive all the propellers (at reduced power) resulting in no yaw (and resulting correction).
Doesn't it just mean a smaller turbine (jet) engine?
I am a little curious about how an aircraft with a takeoff weight of two tons could carry 100 passengers, though. Maybe a blimp with wings?
I am a little curious about how an aircraft with a takeoff weight of two tons could carry 100 passengers, though. Maybe a blimp with wings?
I am a little curious about how an aircraft with a takeoff weight of two tons could carry 100 passengers, though.
https://www.eaa.org/en/eaa/eaa-news-...ight-benchmark
It makes it clear that a 2-tonne MTOW aircraft is what the current engine is capable of powering, whereas 100 seats (actually "50-100") is a design goal for the longer term.
No mention of turbines, either.
Join Date: Jan 2014
Location: N5109.2W10.5
Posts: 720
Likes: 0
Received 0 Likes
on
0 Posts
Hi Dave,
But the article does say "“This innovation will make it possible to build series hybrid-electric aircraft with four or more seats,”
Wikipedia says "http://en.wikipedia.org/wiki/Hybrid_electric_vehicle" that the electric motor part is powered by batteries (short term) and conventional internal combustion engine (longer term).
So unless the aircraft carries a very long extension cable (at least equal to its published range), then there has to be a conventional gas turbine / electricity generator.
No mention of turbines, either.
Wikipedia says "http://en.wikipedia.org/wiki/Hybrid_electric_vehicle" that the electric motor part is powered by batteries (short term) and conventional internal combustion engine (longer term).
So unless the aircraft carries a very long extension cable (at least equal to its published range), then there has to be a conventional gas turbine / electricity generator.
Last edited by Goldenrivett; 11th Jun 2015 at 09:08.
Join Date: Apr 2008
Location: NL
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
My take on it is that it is closer to a Diesel-Electric setup than a hybrid. The breakthrough here being the weight reduction of the electric motor itself. Diesel-Electric has it advantages in high-power installations more commonly found on ships or trains, the downside being the weight of the whole installation, you have to add a generator and an electric motor instead of a gearbox. In big land/sea based power installation having the combustion engine run at a constant speed at its optimum design rpm saves a lot of fuel and will outweigh the weight savings of a gearbox. If Siemens managed to reduce the weight of the generator and electric motor to a point where it becomes a viable installation on aircraft the potential benefits are plentyful. A more redundent power installation, if one generator would fail, all propellors could be powered from the remaining generator(s). Plus the aerodynamic advantages of a much a more flexible system layout.
Many advantages.
Power system (engine) can be placed where it is most effective aerodynamically and also with regard to C of G.
Imagine. The engines aft of the C of G away from passengers and fuel tanks.
However the propulsion can go anywhere the designer seems most effective.
Or vice versa. Engines up front, props at the back.
The powertrain redundancy for the V22 Osprey would certainly be a lot simpler.
Power system (engine) can be placed where it is most effective aerodynamically and also with regard to C of G.
Imagine. The engines aft of the C of G away from passengers and fuel tanks.
However the propulsion can go anywhere the designer seems most effective.
Or vice versa. Engines up front, props at the back.
The powertrain redundancy for the V22 Osprey would certainly be a lot simpler.
Join Date: May 2010
Location: EU
Age: 54
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
A more redundent power installation, if one generator would fail, all propellors could be powered from the remaining generator(s). Plus the aerodynamic advantages of a much a more flexible system layout
Join Date: May 2000
Location: Seattle
Posts: 3,195
Likes: 0
Received 0 Likes
on
0 Posts
The powertrain redundancy for the V22 Osprey would certainly be a lot simpler.
The cross-shaft between the props will still be necessary, since it is imperative that they both provide near-equal thrust. OTOH, you MIGHT be able to get an electric motor on the wingtip that is powerful enough, but smaller/lighter than the turbine. Putting those high-current electric wires to the end of the wings will be a problem itself...
Join Date: Mar 2014
Location: SW USA
Posts: 67
Likes: 0
Received 0 Likes
on
0 Posts
From 4 years ago, at an earlier stage of development:
Siemens - Electricity in the air
"A Siemens electric motor with an output of 70 kilowatts powers the propeller, drawing its energy from batteries mounted in the wings. Once the motor glider reaches its cruising altitude, the pilot switches on a small 30-kilowatt combustion engine. The sole purpose of this rotary engine is to provide energy for the electric motor through a generator, which simultaneously recharges the batteries."
Two years ago at the Paris Air Show, including video:
Siemens Hybrid Electric Aircraft Debuts in Paris [VIDEO] | Electric Vehicle News
"The plane's propeller is powered by a 70kW electric motor from Siemens. Electricity is supplied by a small Wankel engine from Austro Engine with a generator that functions solely as a power source. A Siemens converter supplies the electric motor with power from the battery and the generator. Fuel consumption is very low since the combustion engine always runs with a constant low output of 30kW. A battery system from EADS provides the increased power required during takeoff and climb."
"The next development step will be to further optimize the entire drive train. Siemens scientists are currently working on a new electric motor that is expected to be five times lighter than conventional drives. In two years, another aircraft is expected to be equipped with an ultra-light electric drive."
Press release and photos for the 2015 version:
World-record electric motor for aircraft - Siemens Global Website
World-record electric motor for aircraft
A bit more technical detail on this page:
https://www.siemens.com/innovation/e...ed-flight.html
"This is because an intelligent hybrid drive combining an electric motor and a combustion engine can use turbines that not only are significantly smaller than those of today but can also be continuously operated at peak efficiency during flight. Today’s turbines, by contrast, are designed to deliver a maximum level of power that is only required during takeoff and ascent. Aside from that, they only require 60 percent of their maximum output. 'With a kerosene-electric hybrid drive system, the turbine would run continuously at optimum power and provide energy, via a generator, for the electric motor powering the propeller,' Anton explains. 'During takeoff, extra energy would be provided by a battery.' "
Siemens - Electricity in the air
"A Siemens electric motor with an output of 70 kilowatts powers the propeller, drawing its energy from batteries mounted in the wings. Once the motor glider reaches its cruising altitude, the pilot switches on a small 30-kilowatt combustion engine. The sole purpose of this rotary engine is to provide energy for the electric motor through a generator, which simultaneously recharges the batteries."
Two years ago at the Paris Air Show, including video:
Siemens Hybrid Electric Aircraft Debuts in Paris [VIDEO] | Electric Vehicle News
"The plane's propeller is powered by a 70kW electric motor from Siemens. Electricity is supplied by a small Wankel engine from Austro Engine with a generator that functions solely as a power source. A Siemens converter supplies the electric motor with power from the battery and the generator. Fuel consumption is very low since the combustion engine always runs with a constant low output of 30kW. A battery system from EADS provides the increased power required during takeoff and climb."
"The next development step will be to further optimize the entire drive train. Siemens scientists are currently working on a new electric motor that is expected to be five times lighter than conventional drives. In two years, another aircraft is expected to be equipped with an ultra-light electric drive."
Press release and photos for the 2015 version:
World-record electric motor for aircraft - Siemens Global Website
World-record electric motor for aircraft
A bit more technical detail on this page:
https://www.siemens.com/innovation/e...ed-flight.html
"This is because an intelligent hybrid drive combining an electric motor and a combustion engine can use turbines that not only are significantly smaller than those of today but can also be continuously operated at peak efficiency during flight. Today’s turbines, by contrast, are designed to deliver a maximum level of power that is only required during takeoff and ascent. Aside from that, they only require 60 percent of their maximum output. 'With a kerosene-electric hybrid drive system, the turbine would run continuously at optimum power and provide energy, via a generator, for the electric motor powering the propeller,' Anton explains. 'During takeoff, extra energy would be provided by a battery.' "
Thanks for that last link, from which it's clear that the reference to a turbine was in the context of the upscaled, airliner-class version of the concept, as opposed to the current GA hybrid drive that has a conventional internal combustion engine to generate the electrical power.
Mystery solved!
Mystery solved!
As an aside, I am surprised that HGV trucks don't utilise the diesel-electric method. One whould have thought such a system would save shedloads of fuel, and make the trucks far easier to drive, by doing away with heavy clutches, gearboxes and two speed axles etc.
Join Date: Nov 2004
Location: Perth - Western Australia
Age: 75
Posts: 1,805
Likes: 0
Received 0 Likes
on
0 Posts
Trucks that utilise hybrid diesel-electric drive have been on the market for around 7 yrs at least. There are no really large size units yet, but they will probably appear sometime in the future.
The hybrid diesel truck concept is still effectively in the commercial-proving stage, but the ones in service are providing satisfactory service at lower daily operating cost and with reduced emissions, which are important in urban environments.
However, the diesel hybrid design is complex and comes with more electrical problems and "gremlins" than a regular diesel truck.
Then there is the higher maintenance levels as the hybrid ages. Batteries need to be replaced every few years, and there are more components overall, leading to higher maintenance costs. The diesel-hybrid resale value is also poor.
Then there is the higher potential for fires and electrical short circuits with hybrid designs, due to the substantial increase in the amount of wiring and electrical circuits and components.
The major setback for diesel hydrid market penetration is increased efficiency and cleaner emissions from the newer diesel engines. Regular diesel trucks are a well-proven concept with modest repair costs as compared to hybrids.
Thus, the diesel-hybrid truck (and bus) designs still have a way to go with efficiency gains and lowered "whole of life" owning and operating costs, before they can be proven to be a much more attractive option to purchasers.
Hino Hybrid Light Duty
Hino Trucks / Hino COE - Diesel and Diesel-Electric Hybrid
Volvo FE Hybrid - Volvo FE Hybrid : Volvo Trucks - United Kingdom & Ireland
The hybrid diesel truck concept is still effectively in the commercial-proving stage, but the ones in service are providing satisfactory service at lower daily operating cost and with reduced emissions, which are important in urban environments.
However, the diesel hybrid design is complex and comes with more electrical problems and "gremlins" than a regular diesel truck.
Then there is the higher maintenance levels as the hybrid ages. Batteries need to be replaced every few years, and there are more components overall, leading to higher maintenance costs. The diesel-hybrid resale value is also poor.
Then there is the higher potential for fires and electrical short circuits with hybrid designs, due to the substantial increase in the amount of wiring and electrical circuits and components.
The major setback for diesel hydrid market penetration is increased efficiency and cleaner emissions from the newer diesel engines. Regular diesel trucks are a well-proven concept with modest repair costs as compared to hybrids.
Thus, the diesel-hybrid truck (and bus) designs still have a way to go with efficiency gains and lowered "whole of life" owning and operating costs, before they can be proven to be a much more attractive option to purchasers.
Hino Hybrid Light Duty
Hino Trucks / Hino COE - Diesel and Diesel-Electric Hybrid
Volvo FE Hybrid - Volvo FE Hybrid : Volvo Trucks - United Kingdom & Ireland
Join Date: Jan 2011
Location: Adel
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Won't it be interesting in future...electric props, aerodynamic improvements. Downsizing combustion engines to fit power load. You could bury them inside sound-absorbing intake/exhaust ducting...Heck, you're going to need to tie bells on to let you know when ones sneaking up on you.
As an aside, I am surprised that HGV trucks don't utilise the diesel-electric method. One whould have thought such a system would save shedloads of fuel,
Join Date: Jun 2011
Location: Devonshire
Age: 96
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
"Batteries need to be replaced every few years..."
Our domestic batteries. 18 miles from London, were installed in 1914 and replaced when "The Mains" came available in 1944. They were charged weekly in the Summer, twice weekly in the Winter to provide lighting, only, at 50 volts D.C. The dilute sulphuric was a bit smelly !
Perhaps something better may have been found, now, after a century.
Our domestic batteries. 18 miles from London, were installed in 1914 and replaced when "The Mains" came available in 1944. They were charged weekly in the Summer, twice weekly in the Winter to provide lighting, only, at 50 volts D.C. The dilute sulphuric was a bit smelly !
Perhaps something better may have been found, now, after a century.
Last edited by Linktrained; 14th Jun 2015 at 23:11. Reason: QTH