The 1MW powerplant will be mounted on a De Havilland Dash 8-100 turboprop aircraft, scheduled to perform its first test flight in 2024. The engine and its technology will allow for more efficient engine performance during the different phases of flight, such as take-off, climb and cruise.
The goal of the battery-electric powertrain is to reduce fuel burn and CO2 emissions by 30% compared to a standard Dash-8 turboprop.
I was wondering "why just two props" when reading this, thanks. Because they're reusing an existing airframe makes a lot of sense, even if a lot of benefits from electric airplanes come from adding more, smaller props.
This and most recent articles on the demonstrator are frustratingly light on details. Found some more info on Wikipedia's article on hybrid electric aircraft [0] which cites an Aviation Week article [1] that is unfortunately behind a paywall
> One 2,150 hp (1,600 kW) PW121 turboprop will be replaced by a 1 MW (1,300 hp) gas turbine joined with an electric motor of the same rating, powered by off-the-shelf lithium-ion batteries for takeoff and climb. The turbine is used alone in cruise and drives the motor-generator to recharge the batteries in descent. The downsized engine operates at its optimum for 30% fuel savings over 200–250 nmi (370–460 km). Range is reduced from 1,000 to 600 nmi (1,900 to 1,100 km) due to the higher empty weight and 50% lower fuel capacity.
I've been disdaining the idea of hybrid aircraft for years, thinking there was no way to capture the energy of deceleration (as you can in a hybrid car). Here, though, the rationale is different; you're storing turbine power during descent for use at the next ascent.
I wonder if you could indeed capture the deceleration energy by having the air stream drive the prop and thus the motor/generator. Planes have multiple systems for wasting energy and slowing down (flaps, air brakes, even dropping the landing gear); perhaps this wasted energy could be put into the batteries?
If I understand this right, they're still driving the prop mechanically through a gearbox during cruise, rather than using turbo-electric transmission?
It seems that for militaries without the budget for helicopters or real tiltrotors like the Osprey a hybrid electric quad tiltroter as a replacement. There are a lot of drawbacks, of course, but I'd think the ease of maintenance and ease of training relative to a real helicopter would be a powerful argument for some countries.
It boils down to getting less range for a given payload for any given aircraft. You can exchange less payload for more range until you have nothing but pilots.
It seems to get equivalent power you need to either exchange a third or so of your range or a significant portion of cargo or a mixture of both.
Hydrocarbons do indeed have significantly more energy density and the benefit that once you’ve used them the weight of the fuel goes away giving you less work to do as your fuel runs out.
The idea that you only need the full power for takeoff is nonsense. You also need it for go-arounds, or fighting strong downdrafts, or if you get seriously and quickly iced up and need full power to simply stay aloft, or if your engine #1 goes out and you need to add power on #2....
Check how MANY checklists for how many situations require full power.
Maybe this has applications for unmanned stuff where it is ok to lose the craft sometimes (which explains Raytheon's interest) but for human carrying, this is idiocy, i say again.
I think you misunderstand. The largest use-case for full-power is takeoff, and that is where the most energy savings comes from having an electric motor assist during the full-power need.
That does not mean that full-power would be unavailable for those other uses you mention.
[+] [-] this_steve_j|3 years ago|reply
The goal of the battery-electric powertrain is to reduce fuel burn and CO2 emissions by 30% compared to a standard Dash-8 turboprop.
https://simpleflying.com/raytheon-completes-ground-test-dash...
[+] [-] Symmetry|3 years ago|reply
[+] [-] unknown|3 years ago|reply
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[+] [-] cryptonector|3 years ago|reply
[+] [-] mikepavone|3 years ago|reply
> One 2,150 hp (1,600 kW) PW121 turboprop will be replaced by a 1 MW (1,300 hp) gas turbine joined with an electric motor of the same rating, powered by off-the-shelf lithium-ion batteries for takeoff and climb. The turbine is used alone in cruise and drives the motor-generator to recharge the batteries in descent. The downsized engine operates at its optimum for 30% fuel savings over 200–250 nmi (370–460 km). Range is reduced from 1,000 to 600 nmi (1,900 to 1,100 km) due to the higher empty weight and 50% lower fuel capacity.
[0] https://en.wikipedia.org/wiki/Hybrid_electric_aircraft
[1] https://aviationweek.com/aerospace/utcs-dash-8-hybrid-electr...
[+] [-] dtgriscom|3 years ago|reply
I wonder if you could indeed capture the deceleration energy by having the air stream drive the prop and thus the motor/generator. Planes have multiple systems for wasting energy and slowing down (flaps, air brakes, even dropping the landing gear); perhaps this wasted energy could be put into the batteries?
[+] [-] unknown|3 years ago|reply
[deleted]
[+] [-] LarryMullins|3 years ago|reply
If I understand this right, they're still driving the prop mechanically through a gearbox during cruise, rather than using turbo-electric transmission?
[+] [-] DSingularity|3 years ago|reply
[+] [-] Symmetry|3 years ago|reply
[+] [-] alwaysanagenda|3 years ago|reply
I would imagine hitting the weight limit of traditional aircraft very quickly to get the same output of power.
oil's energy per square inch still can't be beat.
[+] [-] colechristensen|3 years ago|reply
It seems to get equivalent power you need to either exchange a third or so of your range or a significant portion of cargo or a mixture of both.
Hydrocarbons do indeed have significantly more energy density and the benefit that once you’ve used them the weight of the fuel goes away giving you less work to do as your fuel runs out.
[+] [-] dmitrygr|3 years ago|reply
Check how MANY checklists for how many situations require full power.
Maybe this has applications for unmanned stuff where it is ok to lose the craft sometimes (which explains Raytheon's interest) but for human carrying, this is idiocy, i say again.
[+] [-] hcknwscommenter|3 years ago|reply
That does not mean that full-power would be unavailable for those other uses you mention.
[+] [-] snshn|3 years ago|reply
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[+] [-] AYBABTME|3 years ago|reply