Again in January of 2020, we wrote about all the new prototype electrical plane that have been being examined (to see that article, click here) One of many plane featured was the Eviation firm from Israel. The German world delivery firm DHL has introduced that they are going to purchase a dozen Eviation E-Planes, and I’ll let you know why that’s superior information.
_________________________________________________
What’s the Tech?
Electrical programs are fairly easy. The design of the motors and controllers are fairly well-stablished. The massive near-term change with batteries is the choice of solid-state-batteries (SSB’s), so…the one remaining query is “who’s going to go first?” There have been just a few situations the place an organization “dipped their toe” into the electrical airplane sport, however…it seems like DHL and Eviation are the primary ones to dive into the deep finish. The batteries are high-amp items from Kokam in South Korea, and the motors are from MagniX, in Canada.
Whether or not you’re speaking about cargo or human passengers, the aviation business has converted to a hub-and-spoke system, just some a long time in the past. As a substitute of making an attempt to schedule planes to fly from each potential metropolis to each different potential metropolis, small planes carry passengers and cargo on a brief hop to a significant metropolis. There, every thing is moved to a big plane touring to a different main metropolis “hub”.
Everybody appears to hate connecting flights, and needing to get on three totally different airplanes to get to your vacation spot, however…that is the system now we have. The brief hops in the beginning and finish of your flights (the “spokes”), are the half the place electrical plane will have the ability to acquire a market share over the following decade. Not solely are electrical drivetrains extra dependable, fashionable “self driving” programs can cut back the cockpit workload from two pilots to just one.
_________________________________________________
The Eviation Alice
The 2 pics under spotlight the Eviation flying prototype from a yr and a half in the past, and under that, the modifications they made to enhance the design based mostly on potential buyer suggestions wishes.
What they favored:
The physique of each variations has a composite building, which is extra labor-intensive to construct than the traditional aluminum-alloy plane physique. The massive payoff is that the physique is lighter…MUCH lighter. And, it’s going to last more earlier than it must be de-commissioned as a result of stress-cracks. And, as soon as you’re dedicated to a composite building, you all of a sudden have just a few choices that weren’t cost-effective earlier than, however….now that you’re constructing with composites, it prices the identical to think about some artistic choices….
As a substitute of the mass-produced cylindrical physique, the Eviation Alice has a large and brief cross-section. This has two advantages. First, this makes the physique much less affected by cross-winds in all circumstances, but in addition…it makes use of the impact of a “lifting physique”.
You might have heard that an airplane wing is flat on the underside, and is rounded on the highest. This emphasizes “Bernoulli’s precept“, and that is without doubt one of the methods during which a wing creates elevate, and…by having the airplanes physique formed this fashion, the physique provides to the aircrafts elevate. To be truthful, it might not be an enormous impact, however…on the subject of plane, each little bit helps. The extra elevate that the physique generates, the smaller the wings might be, and that reduces drag.
Additionally, they each use well-researched five-bladed propellers, as an alternative of the extra widespread (and cheaper) 3-blade and 4-blade designs. A certain amount of thrust is required, so…by going to a better variety of blades, the propellers can spin at a barely decrease velocity, and now have a smaller diameter. This enables the propellers to spin “gradual sufficient” that their suggestions should not breaking the sound barrier, which ends up in a MUCH quieter plane throughout takeoff. A traditional airplane of this measurement might not be very loud, however…one of many issues that electrical drivetrains excel at is working quietly, and these 5-blade propellers will assist emphasize how extremely quiet these E-Planes might be on the smaller regional airports, with residential properties close by…
It’s the the distinctive torque of electrical motors that enables them to offer sufficient energy to drive large propeller blades at decrease RPM’s.
What they didn’t like:
Having three motors is nice for redundancy (in comparison with solely two), and for the reason that craft wants “X” quantity of thrust to take off with a full load of cargo, the three motors might be individually smaller than the equal thrust of utilizing two barely bigger motors. Nevertheless, two bigger motors might be lighter and cheaper than three smaller ones.
The aviation business could be very litigation-averse and risk-averse. So I have to level out that this primary milestone purchase-order for precise electrical airplanes which can be meant to do actual work are for cargo…not passengers. That being mentioned, even once we are speaking about kerosene-burning jet-engine passenger craft, the complete business has transformed over to utilizing two engines as the popular mannequin, with reasonable-enough security, coupled with probably the most reasonably priced buying and upkeep.
The Ford Tri-motor of 1925, together with the Douglas DC-10 and the Lockheed L-1011 are well-known examples of a 3-engined long-range passenger plane (extra highly effective than two, cheaper than 4). At present, the most important passenger plane nonetheless use 4 engines, just like the Boeing 747, and the Airbus A380. Nevertheless, nearly all of passengers miles are flown with smaller twin-engine plane, just like the Boeing 737 and the Airbus A320. That is essential to grasp, as a result of the shorter ranges are the place the electrical airplanes excel, and plane security regulators just like the FAA really feel that utilizing two engines is the protected and reasonably priced configuration for industrial site visitors.
Push or Pull?
The unique prototype had pusher propellers. One of many points with the rear-most propeller could be the hazard of a “floor strike” on take-off. In fact, a pilot will at all times be making an attempt to take off and land in a reasonably stage orientation, however…dangerous climate and excessive gusts of wind could cause a sudden steep angle, and the rear propeller can hit the bottom.
Even when it’s only a tiny strike, that propeller is toast, and probably even the motor shaft could be broken. Even when cash was no object (and cash will ALWAYS be an object of concern), it takes TIME for an aircraft-certified mechanic to put in a brand new propeller, as soon as you possibly can even discover one. Switching to the traditional tractor-configuration of “pull” propellers will keep away from that concern fully.
Lastly, they modified the tail.
The earlier V-tail can theoretically have much less drag than a traditional tail, with it’s vertical rudder and horizontal stabilizer. The V-tail would possibly even value barely much less. Nevertheless, the latest model with a “T-Tail” could be very well-understood, and it is extremely stall-resistant in adversarial circumstances. The V-tail Beechcraft Bonanza has a really checkered historical past, and no matter why…the New Alice has taken the protected route with it’s widespread T-Tail design.
I’m not a pilot, however I actually just like the Alice having two engines close to it’s centerline within the newest model. I’ve learn many occasions {that a} main good thing about this configuration is in a scenario when one engine has died, and its nonetheless pretty straightforward to regulate the plane.
If the 2 engines are mounted on the wings (and farther away from the centerline of the physique), having one engine fail will trigger an “uneven thrust”, the place the airplane is making an attempt to pivot round, as an alternative of flying straight. In fact the pilot instantly gives laborious rudder to assist the airplane fly straight, however…that causes a whole lot of drag, probably dropping vary and altitude.
Twin-engined planes usually have their engines sized in order that they want each engines to take off if they’ve a full load of cargo, however…they will fly and land safely with just one engine working. That is one space the place electrical motors have confirmed to be extra dependable than inner combustion engines (with a melted piston, melted exhaust valve, or a gasoline leak)
_________________________________________________
The Battery
Everybody in Aviation is anxiously ready on Strong State Batteries (SSB’s). This final yr, there was a growth in electrical airplane prototypes to make sure their firms can have a product that may “hit the bottom working” as quickly because the upgraded SSB’s are prepared for the actual world. Toyota had introduced that they have been going to debut their first industrial SSB through the Olympics in Tokyo, 2021. Nevertheless, that has been delayed. It might have been as a result of Covid points limiting provide traces, however these causes stay to be seen.
Not solely is a Strong State Battery extra fire-resistant, however the huge leap in expertise is their potential to double the vary of a car, per quantity of battery. The 2 autos that will likely be most impacted by this are bikes, and plane.
“…Even with in the present day’s battery expertise, we are able to do brief flights, 100 miles in a retrofitted plane and 650 miles in an plane designed from the beginning for electrical propulsion. To place that in perspective, solely 5% of worldwide airline flights in 2018 have been lower than 100 miles (competing towards local-haul vans), however…45% have been lower than 500 miles. These numbers don’t even embrace cargo flights. So there’s clearly a necessity for these ranges. Why not have them be electrical? Why not have them be clear and quiet, plus lowering the 4% of emissions worldwide generated by aviation…“
I’m within the voltage of the MagniX system used on the Eviation Alice, however I haven’t discovered it but. All I might discover out to this point is that Eviation is now utilizing high-amp cells from Kokam in South Korea (click here). Kokam is a really extremely regarded producer, who made the battery packs for the “Solar Impulse 2” research aircraft (click here).
The battery is unfold out throughout the plane within the wings and fuselage in a manner that optimizes the aircrafts steadiness, to make it as secure as potential. One characteristic of battery-powered plane is that the “gasoline” doesn’t change the load or shift the steadiness of the plane, as it’s used up.
_________________________________________________
MagniX Motors
MagniX Tech is owned by the Clermont Investor Group, based mostly in Singapore. As of January 2021, they’ve moved their analysis facility to Everett, Washington, within the North-West USA, which is close to The Paine Area airport and a significant Boeing facility.
The motors proven under are well-understood inrunners, pretty just like the Motenergy 75-7 discovered on Zero electrical bikes. This type can simply have liquid-cooling added, however…Zero and MagniX each appear to be doing nicely with air-cooling, which saves weight.
From this pic, we are able to see that the primary retail product from MagniX is a “stackable” motor configuration, to fulfill quite a lot of design wants. MagniX has been very clear that they need to take an early lead in conversion kits for current planes which can be already licensed and well-proven.
As a result of security causes, plane engines have to be totally inspected each so many hours of operation, and so they have to be re-built to plane requirements on a really strict schedule, even when they present no indicators of wear and tear or injury. That is referred to as a “Time Earlier than Overhaul”, or TBO. Turboprop engines are dearer to purchase than a piston engine of the identical energy. Nevertheless…turboprops have a for much longer TBO, and that’s the place plane operators have saved cash in the long term. MagniX anticipates their electrical drive programs to have an excellent longer TBO than turboprops.
Your eyes don’t deceive you, this graphic above reveals the Magni500 “double motor” configuration, and it’s utilizing FOUR controllers.
Every motor-module has its motor-phases divided into two teams. In essence, it’s two separate motors intermingled in a single motor housing. Then, every motor has it’s personal controller, to permit half of the module to proceed producing energy if one of many controllers or motors has any concern.
This implies the Magni250 has two motors and two controllers built-in into one system. The Magni500 stacks two of those modules to offer a single drivetrain with 4 motors and 4 controllers. This gives a major redundancy for the utmost in reliability.
The “kV” of the motors is designed to offer the precise RPM’s wanted for plane, so no PSRU discount gear is required between the motor and propeller, additional simplifying the drivetrain.
_________________________________________________
This can be a nice milestone, and reveals that a few of the individuals with huge cash are persevering with to push ahead. I’m chomping on the bit to put in writing extra about Strong State Batteries, however there is no such thing as a new info accessible but.
_________________________________________________
Written by Ron/spinningmagnets, August 2021