Is electric propulsion worth it?

[Dusan]

Short range might work very well for the future "urban air mobility", the average American is traveling 26 minutes to their jobs. Replacing cars with VTOL personal aircraft, my personal commute would be less than 10 minutes instead of 25min, one way.

 

[Dan Thomas]

Short range might work very well for the future "urban air mobility", the average American is traveling 26 minutes to their jobs. Replacing cars with VTOL personal aircraft, my personal commute would be less than 10 minutes instead of 25min, one way.

Just imagine the chaos above the city during rush hour. It's bad enough on the roads where everyone is going the same direction. In the air, with everyone going direct, the risk of midairs would be so great that only computerized, automated flight control in every machine, communicating with a ground control station, could make it workable. The pilot would be a passenger, nothing more.

One has to determine whether going to the office to work on your computer is really necessary anymore. Only the workers that do non-automated hands-on stuff would need to be at the plant. Sometimes we take modern technology and apply it to outdated processes instead of updating the process itself. A solution in search of a problem, so to speak.

 

[Dusan]

It will start slowly, as every high end expensive technology out there, e.g. "horseless carriages", pocket watches, motorcycles, computers, cell phones ... etc. They were at the beginning expensive "toys" for the reach and wealthy, but as the technology progressed it became cheap enough for everyone. So I'm not worried about traffic jams in the sky, when there are more air vehicles in the air, I assume technology will progress enough to maintain separation and not cause problems. I guess an automatic traffic avoidance system could work as a virtual "force field", you fly "virtual" VFR, if you are to intersect another aircraft path or bump into buildings and obstacles, the system will not allow it, automatically redirecting you.

Usually a computer is just a tool to help performing some tasks for most jobs, and there's still need to be in an office, e.g. for me, I'm designing hardware and embedded software, I need to prototype boards, test them and fit them into equipment, so not all of my work can be done from home.

Anyway, what my point here is, to stay on this thread topic, the electric propulsion is good enough even now for the typical commute.

 

[TFF]

I don’t ever see the personal transport being anything but computer controlled. There might be a few motorcycle of the air early craft, but government as it is will squash it. It will be all hands off. A feat of human engineering squashing human spirit. Although there is always a counter, insurance. I would hate to be paying the early vehicle policy and be the first to crash through a roof. This parity put my place of work out of business so you never know. May never happen just because of that.

 

[Dusan]

I would prefer "computer supervised". It will prevent "crashing trough a roof", but not impede the freedom of flight and manually controlling the aircraft if the pilot (well operator) wishes to do so. I strongly believe that's what the majority of people would like as well and it will be a large lobbying to direct the development so.

 

[pictsidhe]

Personal manually piloted aircraft for the average Joe in congested areas is pure sci-fi. People are way too stupid for that to end well. Personal computer controlled aircaft subject to owner maintenance and grounding for problems, the same. Rest assured, the goverment knows that.

Could we have a realistic discussion?

 

[rv7charlie]

Meh. Cars are funneled into tiny arteries and tinier capillaries.
I listened to Burt Rutan talk about air traffic management about 25 years ago at an OSH forum. He said (under the busiest airspace on earth at the moment) to look outside and up. 3D *volume* changes *everything*.

;-)

 

[pictsidhe]

Meh. Cars are funneled into tiny arteries and tinier capillaries.
I listened to Burt Rutan talk about air traffic management about 25 years ago at an OSH forum. He said (under the busiest airspace on earth at the moment) to look outside and up. 3D *volume* changes *everything*.

;-)

That is controlled airspace.

 

[rv7charlie]

So are roads. No doubt we can expect positive control in 'densely populated areas'; ADSB, etc, but congestion should be much milder in 3D. The commercial 'drone' guys are already hitting this hard and heavy, and the FAA has already taken the 1st step with non-commercial 'hobby' operators.

This might be the 1st time the FAA is taking the lead on innovation, dragging the rest of us along, kicking & screaming (not that I endorse the draconian hobby drone rules, mind you).

 

[jandetlefsen]

Pipistrel has two SkyCharge version:

• €36,000 SKYCHARGE Charging station with 2 charging sockets 15 kW, each, single phase, 85-265 Vac, 45 - 65 Hz
• €36,000 SKYCHARGE Charging station with 2 charging sockets, 20 kW, three phase, 380 Vac, 45 - 65 Hz

 

[pictsidhe]

Pipistrel has two SkyCharge version:

• €36,000 SKYCHARGE Charging station with 2 charging sockets 15 kW, each, single phase, 85-265 Vac, 45 - 65 Hz
• €36,000 SKYCHARGE Charging station with 2 charging sockets, 20 kW, three phase, 380 Vac, 45 - 65 Hz

Price is in euros... I'd be amazed if they couldn't supply 208 and 480v 3ph chargers for the American market. The 380 may do 480 with no alterations.

 

[Sunbird]

- Efficiency of the electrical system does not change significantly with power setting. The electrical power plant is happy at 20% power setting, where the aircraft aerodynamically has the best range, endurance whatever. An ICE, piston and even worse for turbine, reducing the power setting reduces drastically the efficiency.

A while back Rotax or somebody had come up with a 912 IC with an electric engine mounted on the prop shaft behind the propeller. The idea sounded excellent; IC plus electric for take-off, IC only at optimum rpm for cruise plus recharge of battery. The weight penalty of the electric engine plus 5 minute battery vs bigger IC engine may balance each other out. However, less complexity and costs by going with only bigger IC engine seemed to have won out, since I have heard nothing more of the idea.

But for some missions this may be an answer. For example, vertical takeoff require a lot of power for 30 to 40 seconds until transitioned into forward flight, then flight can continue (IC engine) with much lower power requirements. Nearly all electrical engines are of course designed with continuous power delivery in mind, specifying cooling needs. What if an electric motor is designed with just this 30 - 40 seconds of enormous power in mind? With a battery/capacitor system sized for this power delivery? An example of this idea is the electric starter motor of an IC engine like in your car, lot of power for a short time, not to be used continuously.

 

[TFF]

A starter motor is only about 2 horsepower. The issue is weight of the batteries. Power to weight, the 60 second battery pack weight is probably equal to an hour of gasoline. Not a good trade.

 

[pictsidhe]

I looked at an electric boost. Decided I'd be better off temporarily increasing piston power with HP and cooling tricks. Water injection is the ace up my sleeve. Cheaper and lighter in my case to stay piston.

 

[Sunbird]

Not a good trade

Depends on the mission. I would not miss that hour of gasoline if it would enable vertical takeoff.

 

[henryk]

gasoline

AeroDelft - Project Phoenix

Project Phoenix is the first of its kind: it is the world's first liquid hydrogen-powered aircraft and the first to fully implement active drag reduction.

aerodelft.nl

=H2 !

 

[Sockmonkey]

AeroDelft - Project Phoenix

Project Phoenix is the first of its kind: it is the world's first liquid hydrogen-powered aircraft and the first to fully implement active drag reduction.

aerodelft.nl

When it mentions all those tiny suction holes in the wing I can't help but wonder what happens if you fly through a dust cloud or a swarm of bugs or anything really. How much work is it gonna be to inspect and clean those passageways out after every flight?

 

[henryk]

tiny suction holes in the wing

DIANA 2, bottom of wing TE=

https://pl.rec.paralotnie.narkive.com/sRYuEBdZ/latanie-w-deszczu:i.19.2.full

 

[Dan Thomas]

When it mentions all those tiny suction holes in the wing I can't help but wonder what happens if you fly through a dust cloud or a swarm of bugs or anything really. How much work is it gonna be to inspect and clean those passageways out after every flight?

I worked on a Cessna 400 that had the weeping-wing anti-ice system. Zillions of lasered holes, too tiny to see, on a stainless leading edge cover. Too small for bugs to plug, really, but any dust or other contaminants would cause trouble. The holes in this wing are .12 mm, about .005", a lot larger and lot more likely to make huge trouble in the rain. And the claim of a 50% reduction in profile drag is not supported by any evidence whatever on the website. All of it makes one skeptical, at least. It's just another case of wait-and-see for some proof that it all works just fine.

 

[pictsidhe]

Delft have been working on boundary layer control with suction and other tricks for a long time. Plenty of published research from them. They are a top aero University.
MSSU also worked on BLC, there are a few papers available. Sadly their guru, August Raspet met a premature end.