from Hacker News

Raytheon completes engine run of hybrid-electric flight demonstrator

by thealienthing on 12/21/22, 4:11 PM with 32 comments

by this_steve_j on 12/21/22, 5:48 PM
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.
https://simpleflying.com/raytheon-completes-ground-test-dash...
by mikepavone on 12/21/22, 6:08 PM
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.
[0] https://en.wikipedia.org/wiki/Hybrid_electric_aircraft
[1] https://aviationweek.com/aerospace/utcs-dash-8-hybrid-electr...
by Symmetry on 12/21/22, 10:30 PM
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.
by alwaysanagenda on 12/21/22, 7:58 PM
how large can you scale electric airplanes with hyper-dense battery cells?
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.
by dmitrygr on 12/21/22, 7:11 PM
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.