> 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...
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?
On a smaller scale, all jet airliners have a RAT (Ram Air Turbine), which is just a propeller that drops into the airstream if both engines fail. It provides hydraulic pressure and electrical power during an emergency.
Hard to believe that putting a vortex-generating turbine and a generator into the airstream will improve efficiency against that.
And some airplanes are already capable of pushing back under their own power. The reason we don't do that is not the plane -- it's the airport. The blast can damage the airport, ground equipment, and endanger people.
If I understand this right, they're still driving the prop mechanically through a gearbox during cruise, rather than using turbo-electric transmission?
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...
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.
That does not mean that full-power would be unavailable for those other uses you mention.
One nice thing about electric motors is that they can be "throttled up" almost instantaneously, unlike some (not all) turbines. For example, that ultra fast response may be useful in a wind shear situation.
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.
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.
