Electric Airspeed Record.
Discussion
Here's a little insight into a project I'm consulting on at the moment post Bloodhound SSC, aiming for "over 300mph" (will be nearer 400mph than 300mph IMHO) with an electrically powered aircraft.
https://www.dailymail.co.uk/sciencetech/article-65...
https://electro-flight.com/
There's an awfully long way to go before electric planes are mainstream but it's just the start.
https://www.dailymail.co.uk/sciencetech/article-65...
https://electro-flight.com/
There's an awfully long way to go before electric planes are mainstream but it's just the start.
The landing strip on the Welsh coastline mentioned in the daily mail im guessing it’s Llanbedr?
Really interesting this aircraft are they designing and building their own airframe or is it a modified airframe?
https://www.rolls-royce.com/~/media/Files/R/Rolls-...
Really interesting this aircraft are they designing and building their own airframe or is it a modified airframe?
https://www.rolls-royce.com/~/media/Files/R/Rolls-...
I don't want to sound a downer, on things, and this is clearly a fun little project, but it's not really pushing any useful boundaries? I mean, propeller aircraft can fly faster than 400mph (and have done so for nearly 90 years now (407.5mph in 1931)), the yasa motors are nothing special, the batteries, and nothnig special, the plane itself, whilst i'm sure it will be reasonably trick, isn't particularly novel as far as i can tell. And critically, it doesn't help electricfy air transport, because it doesn't solve the single stumbling block of insufficient energy density? So other than generate some nice column inches for RR, what does it achieve?
The thing is, "insufficient energy density" isn't the only stumbling block in electrifying air transport. The integration of all those components you mention, whilst proven individually in different applications, into a homogenous airworthy system introduces new challenges, many of which don't get realised until you try to do it for the first time. If you look across the variety of programmes associated with electric / hybrid aircraft, as far as I can see they're all trying to take bites (sometimes the same bite, sometimes different) of a big mammal that people assume is an elephant, but is turning out to be something different.
Edited by Mave on Friday 4th January 23:51
I think it is a very worthwhile project but what could change electric flight is to use photo electric cells as structural elements for the the wing skin. I know they have used solar panels on very lightweight long distance planes, but I believe they were attached to the carbon fibre wings?
Flying Phil said:
I think it is a very worthwhile project but what could change electric flight is to use photo electric cells as structural elements for the the wing skin. I know they have used solar panels on very lightweight long distance planes, but I believe they were attached to the carbon fibre wings?
I agree about using solar panels as structural elements - that would the giant leap forward needed.I see this is a stepping stone to the future. It is a proof of concept. Can electricity power a significantly heavier-than-air aircraft? The idea needs to be sold to the public and it's better sell them the idea via an aircraft that looks like a Spitfire than a Spruce Goose.
The future will be seen as a step backwards. It will take over 12 hours to cross the Atlantic, but it will be done is an aircraft that is zero-emissions.
I do wonder where the energy is going to come from. We don’t even generate enough renewable energy to power all cars yet, and are a long way from it. I took this screenshot of Plane Finder just now, 4.54am. Solar panels on aircraft would be largely wasted for great chunks of a working year.
However, what a great project to be Involved in. Roll on cold fusion!
However, what a great project to be Involved in. Roll on cold fusion!
Flying Phil said:
I think it is a very worthwhile project but what could change electric flight is to use photo electric cells as structural elements for the the wing skin.
what?Even at very high altitudes (above the clouds and the highest density of air), where you can get solar intensities 4 times greater (or more) than at ground level, the wing area of a typical plane would be too small to really do that much.
Consider a 747 with a total wing area of roughly 500m^2. Somehow we fill every last square cm with a solar panel, and somehow they all get the same maximum efficiency (impossible due to the requirement to shape the wing to work, er, as a wing), even at 4kW/m^2 that's just 2 MW.
Ok, that's a big number, but each RR RB211 on the 747 develops a maximum of 258kN of thrust at an massflow of 728kg/s, which is a power of just about 45MW, and there's 4 of them fitted to that plane.
If we consider cruising at about 85% of peak thrust (fairly typical for a wide body jet), the engines would therefore be making 153MW, so the additional power from the solar panels could, at absolute best (assuming they have no effect on drag or mass) add an additional 1.3% range.....
Mave said:
The thing is, "insufficient energy density" isn't the only stumbling block in electrifying air transport. The integration of all those components you mention, whilst proven individually in different applications, into a homogenous airworthy system introduces new challenges, many of which don't get realised until you try to do it for the first time. If you look across the variety of programmes associated with electric / hybrid aircraft, as far as I can see they're all trying to take bites (sometimes the same bite, sometimes different) of a big mammal that people assume is an elephant, but is turning out to be something different.
Sorry, but i disagree in general terms. Sure, there are individual, small scale, optimisation studies needed, but broadly, we are talking about turning a prop (100% understood tech) by an electric motor (100% understood) and powering that with a battery system (100% understood). Edited by Mave on Friday 4th January 23:51
The only thing i can see that actually matters is maximising the energy density of the batteries, but given that this would have to increase by more than 10 times to get any practical "commercially viable mass transit" aircraft to work, you are not going to do that without a major step change in battery architecture, meaning a project to just stuff a few existing batteries in a small, custom plane designed for one task, isn't exactly breaking much new ground....
Max_Torque said:
Mave said:
The thing is, "insufficient energy density" isn't the only stumbling block in electrifying air transport. The integration of all those components you mention, whilst proven individually in different applications, into a homogenous airworthy system introduces new challenges, many of which don't get realised until you try to do it for the first time. If you look across the variety of programmes associated with electric / hybrid aircraft, as far as I can see they're all trying to take bites (sometimes the same bite, sometimes different) of a big mammal that people assume is an elephant, but is turning out to be something different.
Sorry, but i disagree in general terms. Sure, there are individual, small scale, optimisation studies needed, but broadly, we are talking about turning a prop (100% understood tech) by an electric motor (100% understood) and powering that with a battery system (100% understood). Edited by Mave on Friday 4th January 23:51
Edited by Mave on Saturday 5th January 14:02
Mave said:
How about the high current electrical distribution system with high frequency switchgear next to sensitive avionics, operating at altitude? 100% understood? How about what happens if you have a battery failure and need to isolate it but the propellor is still windmilling - is the system fault tolerance 100% understood? And are the design rules for, say, the motor really understood? Are they high g / high vibration capable? Have they been designed to safely accommodate overspeed in a high speed dive case?
I've developed high performance inverters that meet MIL spec EMC! (Trust me, that is quite hard, but it is already understood how to do this)Altitude, no issues, the electronics are solid state and sealed, and the bus bars are trivial to insulate if necessary (unlikely to be an issue below 1KV)
Propeller windmilling, is no issue, either with an invert that has active short circuit (if prop braking is required) or by simply disconnecting the main battery contactors if the prop needs to freely windmill.
In terms of motor, an aircraft is fairly trivial, compared to say the motors already developed for F1 THERS and FormulaE. High G is no issue likewise. Motor design is these days straight forwards and already many parametric design tools are available to spec the motor right off the bat (and this project is using OTS motors from Yasa)
Ultimate overspeed is no different to having a prop attached to an ICE. At some speed, eventually the engine goes bang if it is grossly overspeed, however with the inverter using active short circuit, you can prevent this by providing as much braking torque as you can drive torque (not something that is possible with an ICE, where motoring friction is ~10x lower than driving load.
The Boeing 787 places heavy use on batteries - although they have caused problems.
https://en.wikipedia.org/wiki/Boeing_787_Dreamline...
https://en.wikipedia.org/wiki/Boeing_787_Dreamline...
Max_Torque said:
I've developed high performance inverters that meet MIL spec EMC! (Trust me, that is quite hard, but it is already understood how to do this)
What sort of power density are they? All the ones I've seen at 100kW+ have been prohibitively large and heavy for this kind of application (although to be fair the last time I was actively working in this area was 2015)Max_Torque said:
Altitude, no issues, the electronics are solid state and sealed, and the bus bars are trivial to insulate if necessary (unlikely to be an issue below 1KV)
Even at 40k feet +? I'm aware of concerns over winding insulation breakdown and switchgear arcing at high altitude, especially when you are trying to keep the winding density high to get a decent power densityMax_Torque said:
Propeller windmilling, is no issue, either with an invert that has active short circuit (if prop braking is required) or by simply disconnecting the main battery contactors if the prop needs to freely windmill.
If you short circuit it, what do you do with the power? If you dissipate it as heat, then the cooling system needs to be an order of magnitude larger.If you let it free wheel, then you need to make sure it won't burst during overspeed which, again, may limit the power density.
I'm not saying any of this is insurmountable, far from it, but getting to the point where you've managed to specify all the bits of the system in a way where the work together effectively, with sufficient evidence to allow you to fly, is a journey worth doing in its own right, if for no other reason than to practice in advance of scaling up to something larger.
Max Torque makes some very good points but seems to assume a direct substitution of solar electric for gas turbine. I would have thought an electric powered passenger plane would be optimised slightly differently ie slightly lower speed, lighter weight, larger proportional wing area, small but useful on board batteries for max power, charged up when on the ground or when descending.......obviously we are in the early days of a revolution but CO2 emissions from Aircraft could well be the next environmental target. IN5IGHT is getting in on the ground floor!
Flying Phil said:
Max Torque makes some very good points but seems to assume a direct substitution of solar electric for gas turbine. I would have thought an electric powered passenger plane would be optimised slightly differently ie slightly lower speed, lighter weight, larger proportional wing area, small but useful on board batteries for max power, charged up when on the ground or when descending.......obviously we are in the early days of a revolution but CO2 emissions from Aircraft could well be the next environmental target. IN5IGHT is getting in on the ground floor!
You beat me to it. I was going to post similar comments.MT is assuming that 400 people will be crossing the Atlantic at 600 knots in these aircraft.
I see it very differently. I can see it being used for cargo. 100 tons crossing the Atlantic at 250 knots.
The point about night flying is a very valid one, but it will soon be the case that if you can see, you can generate
.ash73 said:
Batteries are heavy, so let's put them in an aeroplane. Stupid idea.
That's killed it, I doubt a single person on that project ever thought about that. Unless an electric parrot is heading this way.I think this is a great project and there are so many commercial advantages to electric aircraft. As I understand it EasyJet are investing a fair amount into the concept. Something they pointed out, that I hadn't considered, is the idea of having more late night flights because they are currently restricted due to noise issues.
So far they are only looking at short distances but the kind that are perfect for the UK. Sounds similar to the motoring world where they talk a lot about the final mile but with the big distance stuff using a different technology.
I know these kind of projects will have their doubters but there were people saying an aircraft would never cross the Atlantic not too many years ago.
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