Electric Aircraft

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ian16th
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Electric Aircraft

#1 Post by ian16th » Wed Sep 16, 2020 2:05 pm

An interesting article.

Well I thought so.
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Re: Electric Aircraft

#2 Post by Pontius Navigator » Wed Sep 16, 2020 2:42 pm

The thing that first grabbed me was "to really get off the ground aviation will need a new generation of energy storage technology".

Now I realise they were talking of vertical take off but even for conventional take off an aircraft needs full power. I then thought of EMALS. If airfields had EMALS installed it could transfer a lot of the power needed from the aircraft to the ground.

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Re: Electric Aircraft

#3 Post by TheGreenGoblin » Fri Sep 18, 2020 5:16 pm

The recently certified Pipistrel Velis Electro has completed flights intended to set records for electric aircraft. Between the end of August and Sept. 2, Pipistrel says that “five world records tumbled the combustion aircraft: your aircraft used less than a quarter of the energy for the route than conventional planes.” Due to the lack of infrastructure, the flights required two ground crews in electric cars that “had to drive two chargers in a rabbit and hedgehog game in front of the plane,” the company said. “The aircraft flies at about 120-150 KM/H in a straight line, the cars have to adapt to the road conditions. Meticulous planning was necessary to minimize waiting times when loading.”


The total distance flown for the record flights, the data for which has been submitted to the FAI for validation, was 523 MI or 839 KM.

According to Pipistrel, the following records have been set.

Lowest energy consumption (kWh / 100 KM): Using a claimed 190.963 kWh of electrical energy, the Velis averaged “22.76 kWh / 100 KM, which corresponds to 2.33 [liters of] diesel (energy equivalent diesel: 9.75 kWh / l)…calculated over the entire distance, the Pipistrel Velis consumed the energy equivalent of 19.58 liters of diesel!” Pipistrel says this performance “puts the aircraft in the range of a Tesla Model S, making it a new benchmark in aviation. Comparable aircraft with internal combustion engines would consume about 4x to 5x more energy.”

Highest average speed over 700 KM (KM/H): The Velis averaged 125 KM/H (77 MPH) over 738 KM (459 MI). The team also believes it set a speed record over 100 KM distance of 136 KM/H (85 MPH).

The Velis also supposedly set records for the “longest electrically flown route,” 327 KM (203 MI) over 24 hours, 608 KM (377 MI) over 48 hours, and 839 KM (523 MI) over 56 hours. The team was planning to conquer climb-rate and absolute altitude records for electric aircraft but the weather did not cooperate.

“Electric flying is still limited in range today and so a lot of logistical effort had to be accepted for this long-haul flight,” the team said in a statement. “However, the aircraft was not originally intended for such a use: The Velis is a training aircraft for training pilots close to the airport, and it is ideally suited for this: practically inaudible, locally emission-free and cost-reduced.”



http://www.avweb.com/aviation-news/pipi ... d-flights/
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Living Next Door to Alice!

#4 Post by TheGreenGoblin » Wed Apr 14, 2021 4:16 pm

Who the $%$ is Alice?

The Eviation Alice of course...

I must say I do wonder how this aircraft will handle with props at the tips of the wings and a V tail? What will Vmc be for this aircraft?

What's with that tail wheel? It almost looks like a tail dragger!



Apparently the engines will be be relocated but why put them at the end of such a long lever in the first place?
At the June Paris Air Show, a full-size static Alice was exhibited. The first airline customer was announced: Hyannis, Massachusetts-based Cape Air. Cape Air ordered 92 aircraft, priced at $4 million each. MagniX investor Clermont Group from Singapore took a 70% stake in Eviation Aircraft in August 2019. By October 2019, over 150 Alice aircraft had been ordered by two American companies. Further investment of $500 million was still needed to begin serial production.

On 22 January 2020, a fire broke out and the prototype was destroyed. No one was injured. The fire broke out in an under-floor battery compartment located in the “operator/passenger area”. On 18 May 2020, GKN Aerospace announced their partnership with Eviation on the design and manufacture of the wing, empennage and electrical wiring interconnection system of subsequent Alice airframes. By December 2020, Eviation expected to fly a modified Alice design in 2021, with the wing-tip motors relocated, before certification in the second half of 2023.
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Re: Electric Aircraft

#5 Post by Pontius Navigator » Wed Apr 14, 2021 4:30 pm

The stated ceiling of 12,500 ft suggests no oxygen system. I would guess it would cruise at lower altitudes and use the wind speed and direction to get best performance.

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Re: Electric Aircraft

#6 Post by TheGreenGoblin » Wed Apr 14, 2021 4:34 pm

Pontius Navigator wrote:
Wed Apr 14, 2021 4:30 pm
The stated ceiling of 12,500 ft suggests no oxygen system. I would guess it would cruise at lower altitudes and use the wind speed and direction to get best performance.
That is covered in the video. The prototype is not pressurised but it is designed to be operated at up to FL 280 in its second production release.
Two variants of the Alice were originally planned. The initial, unpressurized model is intended for air taxi operations, with energy stored in a lithium-ion battery. Eviation was working on building a prototype scheduled to fly in early 2019. In 2017, a second pressurized model was to be an extended-range ER executive aircraft available by 2023 for $2.9 million, with a more powerful aluminum-air battery with a lithium-polymer buffer, a cabin pressurized to 1,200 m (4,000 ft) at FL 280, G5000 avionics, a 444 km/h (240 kn) cruise and 1,367 km (738 nmi) range. In October 2019, Eviation described only the pressurized Alice Commuter with a 260 kn (480 km/h) cruise speed.
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Re: Electric Aircraft

#7 Post by Pontius Navigator » Wed Apr 14, 2021 4:48 pm

What advantage would that height confer?

Avoidance of icing and cumulo granite. Capturing greater tail winds. Lower drag. Certainly fuel efficiency would differ from hydrocarbon engines.

I mentioned before that flight at 18,000 feet against a lower head wind than 39,000 feet, and the fuel burn saving from avoiding the extra climb, saved fuel and time.

In Nav training performance didn't feature highly. We would climb at 130kt IAS. Cruise at 160kt 5,000ft and 150lt above that to 14,000.

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Re: Electric Aircraft

#8 Post by TheGreenGoblin » Thu Apr 15, 2021 6:06 am

Well it seems that some of the main concerns I raised in my first post have been heeded. Primarily the potential engine out control issues relating to the engines on the wing tips, the aircraft's V tail and it's cross wind handling and landing characteristics as a taildragger, despite the much touted computerised differential engine power/pitch/rpm governor to offset crosswind in the landing configuration (as described in the video link above).

Eviation may have radically changed the design of its all-electric Alice aircraft, ditching the wingtip- and tail-mounted pusher props in favour of a more conventional configuration.

An unverified image obtained by FlightGlobal shows a possible evolution of the Alice that features two propellers mounted on the rear fuselage. It also has a T- rather than V-tail and, apparently, tricycle landing gear.

Israel-based Eviation declined to comment about potential changes to the design of the nine-passenger aircraft. “At the present time, we do not have information we can share,” the company says.
76218_eviationalice_390777.jpg

As opposed to

76219_eviationalice_557083.jpg

https://www.flightglobal.com/airframers ... 88.article
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Re: Electric Aircraft

#9 Post by TheGreenGoblin » Thu Apr 15, 2021 6:16 am

Pontius Navigator wrote:
Wed Apr 14, 2021 4:48 pm
What advantage would that height confer?

Avoidance of icing and cumulo granite. Capturing greater tail winds. Lower drag. Certainly fuel efficiency would differ from hydrocarbon engines.

I mentioned before that flight at 18,000 feet against a lower head wind than 39,000 feet, and the fuel burn saving from avoiding the extra climb, saved fuel and time.

In Nav training performance didn't feature highly. We would climb at 130kt IAS. Cruise at 160kt 5,000ft and 150lt above that to 14,000.
All of the good things you note PN and, of course, a smoother more comfortable ride for the passengers, out of the worst of the weather that cruising at lower altitudes often doom you to, as well, as most important, from a potential sales perspective, cruise performance parity with other more conventional turboprop aircraft in this general (now including electric) class, which implies +- FL 280!
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Re: Electric Aircraft

#10 Post by Pontius Navigator » Thu Apr 15, 2021 7:39 am

TGG, once, fresh out of training and going somewhere North with my boss, both pax in the back of the Anson, I was disappointed when we turned back. We had been bumbling along in dark grey clouds, ice building on the wings, and chunks flying off the props. I have no recollection of why we were doing it.

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Re: Electric Aircraft

#11 Post by TheGreenGoblin » Thu Apr 15, 2021 8:07 am

Pontius Navigator wrote:
Thu Apr 15, 2021 7:39 am
TGG, once, fresh out of training and going somewhere North with my boss, both pax in the back of the Anson, I was disappointed when we turned back. We had been bumbling along in dark grey clouds, ice building on the wings, and chunks flying off the props. I have no recollection of why we were doing it.
The last time this happened to me, some 3 years back now, I was en route from the Black Isle (next to the Tain Range which I guess you know very well) to visit C16 in Perth, fully India Mike Charlie, over the Cairngorms, with a recently lapsed IMC rating, in a light aircraft with no anti-icing kit, not cleared for flight into icing conditions, as the wings frosted over with no way to climb, or descend (fortunately I had another pilot next to me to field radio calls allowing my brain cell more space to focus ). One can only imagine the AAIB report if it had gone tits up... the things we do for fun eh! ;)))

All worth it mind you to meet up with a very charming chap. I must renew my UK ‘Instrument Rating (Restricted) this year.
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