Great video. Thankyou. Archer does admit the Midnight is not the best eVTOL out there. They just want to fast track something that gets to market. Joby are years ahead with their research and development, and way ahead with FAA cert testing. Nov 6th 2024, Joby Aviation (NYSE:JOBY) is 41% through Stage 4 FAA cert testing, expecting FAA certification in 2025. Cash position: $710m plus the following to be added: PLUS Early October 2024, Toyota made an agreement to invest a further $500m into Joby in 2025. PLUS Late October 2024, Joby raised $230m. (less costs, call it $220m) PLUS Delta Airlines will further invest up to $140m as milestones reached. PLUS Saudi Arabia MOU for an undisclosed number of S4's - fast tracking income while air taxi builds out PLUS $130m DoD contract. PLUS Marina factory producing 12 eVTOLs per year expanding to 25 per year. PLUS Dayton factory (my estimate of production ramping up) 2026: 150 eVTOLs 2027: 400 eVTOLs 2027: 500 eVTOLs. So Joby has a huge cash runway (over $1.7 billion) plus up to $325 million in incentives and benefits. Within 2028 they will have more than 1000 eVTOLs producing cash. Note: The state of Ohio and several political organizations have offered up to $325 million in incentives and benefits to develop the new Dayton factory, expected to be ready 2025. Incentives include grants, tax credits, and infrastructure support, as well as workforce development assistance aimed at helping Joby hire and train approximately 2,000 employees for the factory. My estimates for production: Cumulative values 2024 Marina 6 Dayton 0 2025 Marina 18 Dayton 0 (Dayton will be ready at this point) 2026 Marina 32 Dayton 150 2027 Marina 48 Dayton 550 2028 Marina 66 Dayton 1050 I have allowed ramp up for both Marina and Dayton. Total in 2028: 1116 eVTOLS. "..A Joby Aviation S4 2.0 aircraft is projected to generate $2.2 million in annual revenue.." So from 2028 that is $2.45 billion earnings. The average tech sector P/E ratio is 33, implying a market cap of $81 billion by then, or a share price of $106. The share price is currently $6. Joby's vertical integration is its superpower. Joby MTOW is 5300 lbs, Archer MTOW is 6700 lbs (same number of passengers). So Joby is more energy efficient. Joby is faster at 200 mph. Joby has longer flight duration which makes it more versatile. Joby S4's first piloted flight September 2023. Archer have not yet piloted a flight. I suspect Archer could be a year behind with FAA cert. Joby 41% through fourth stage (FAA testing) in Nov 6th 2024 report. Note in 2023 they obtained a clear path to certification of their pouch battery. Tail approval is highly significant - materials and structure. Joby S4's hover noise is 67dBA, far quieter compared to Archer. Joby's on-wing flight 100 times quieter than a helicopter. For Archer, noise could be a big approval problem for operating in cities. Both Archer and Joby have a former FAA administrator on the board. Joby are producing pre-production prototypes as promised (4th being finalised, possibly 5th by end of 2024). There is no evidence of Archer rolling out prototypes. Indeed, Archer made the comment during 7th Nov report that they don't want to say when the test prototype (singular) will be ready because that would put undue pressure on the team - that's not good enough and leads to the question: are Archer potentially hiding something? It is the very essence of the company and Archer can't give an approximation? Joby ditched gear boxes years ago. Their six direct drive motors are simpler, lighter, lower maintenance. Archer still on gear boxes. Archer's motors weigh 300Kg in total, Joby's total is 168Kg. Joby has 10,000+ hours of flight data so far. Joby will be first mover, its vertically integrated production cheaper, more reliable and more agile. It's aircraft weight, speed, duration and noise superior. Just my thoughts. No investment advice given.
Thanks for the interesting write-up and analysis! You mentioned that Joby’s on-wing flight is 100 times quieter than a helicopter. I would double-check this value because I think it is incorrect. Joby had stated this 100x quieter value several times, but it is not a fair description of the reduction in perceived loudness. For this reason, I would generally recommend everyone following the eVTOL industry to learn more about aircraft noise and aeroacoustics. Recently, I did a deep analysis on eVTOL noise, including a deep dive on Joby’s patents on noise optimizations. You can watch the video here: ruclips.net/video/8BjlAqNz5QM/видео.htmlsi=Nr1BELUirDwKO6-v
Great analysis. You validated my points I’ve been saying about Archer as Joby seems to be the winner when compared against each other. I believe the drag of the rear motors and extra weight alone is enough to rule out archer. I have never seen a full transition of flight in any released video from archer. Which been a RED flag for me as I do like there cockpit design but see many negative factors to their design choice and choice to use a gearbox. I have some electric motor experience since 2005 and I can tell you, a gear box is a negative for electric motors as those gears will need constant maintenance and eventually a full replacement.
You talked about the structure of some motors, which is very interesting, but the most important parameters of the motor are still efficiency. Efficiency determines the life of the motor. Of course, it is necessary to understand this concept.
Great videos, John. I'd love to see a high level video on what architectures you think are best for different business models. Also love to get your thoughts on Overair's butterfly
Boy this is a great video! I'm hopefully that eVTOLs will soon be flying commercial routes. But as this video makes clear there are huge engineering challenges involved. If you listen to these companies spokespersons, they are all also clear that they hope to achieve some level of autonomous flight. I wonder which company is the furthest along in flight automation?
Excellent video and analysis. I was for both, you can see me in them. And it's uncanny how different both companies are and still share similarities. I'll update my article to include your link. Spot on!
I’m also interested to see how both compare in noise levels. Nasa did acoustic testing back in 2022 for Joby. Very impressive stats for Joby especially when compared to many other aircrafts. I haven’t seen any acoustic validation for Archer yet. Would love to see Archer’s and how they compare at take off/ landing and full transition flight.
Excellent analysis videos, like the other ones on your channel. Really informative. Based on your previous videos comparing propulsions of Joby Aviation and Vertical Aerospace, and now the comparision between motors of Archer and Joby, I wonder what you think about Alia eVTOL by Beta and where it fits along with the other three.
Hi there! I think Beta's Alia eVTOL is a simpler design, so it could get certified and come to the market first. However, this advantage could be temporary, as it depends on the certification of eVTOL aircraft with better performance. On the other hand, other eVTOL aircraft may not get certified at all. So, I think Beta's eVTOL is a product with lower risk but also lower potential. Best, John
Flying the BETA without lift props is significant - it makes a mockery of the wing booms and weird ultra swept tail though --their props are also 'unusual' and unlikely to be efficient (2 blade scimitars ) --the sheer SIZE of these monsters is only apparent when somone walks under a wing with a foot or more to spare --and these are only four seaters (the other dozen or so 'stowaways' are in the battery compartment ...)
What do you think about the 28kg weight of the motor and inverter combined? Do you think that includes the weight of Thermal management system, coolant, housing, the additional devices to withstand the mechanical load (like a bearing)?
The speaker at the Joby presentation mentioned that their direct drive motor had been patented. I imagine you could perhaps answer some of your questions about it, if you were able to find that patent. I did some brief searching online, but the closest thing I found was a Joby patent on Justia for an "Aircraft propulsion unit." This doesn't seem to be for the motor itself. Perhaps the patent has been filed, but not published, yet? Or I just wasn't looking in the right place....
Again, great content, thanks! Interesting how the leading companies with such similar design requirements comes to two completely different conclusions. Jobys numbers sure seem to good to be true, I do hope they match reality, that would be great for the development of all future electric manned flight vehicles! Time will tell. I like the idea of dual winding (split stator?). If the dual winding also comes with dual esc, that might provide a sort of esc-motor redundancy within a single motor housing. Kind regards/Axel
Thanks again, fascinated to see the gen 2 VX4 aft rotors at work and in transition! With any luck that will be early - mid 2024. Also, if I could request more VX4 content, I would appreciate it!
Thank you for yet another great analysis! I really enjoy your in-depth videos. I'm really curious to hear, did you see Liliums recent battery webinar, and what did you think of it?
Hi! I'm glad you like these kinds of videos; thank you for your viewership! Yes, I've seen Lilium's recent battery webinar. Overall, I think it's an excellent presentation with clear and concise explanations. And it's positive to see Lilium's leadership team address some of the industry's concerns and engage with the public. However, in terms of content, I haven't seen anything in the presentation that would change my previous conclusion. Information about Lilium's batteries was already released more than a year ago (e.g., lilium.com/newsroom-detail/liliums-battery-strategy), so the battery webinar didn't bring new perspectives in this regard. Whilst batteries with high silicon content in their anodes can have outstanding performance, their adoption has been historically limited by numerous problems. I imagine Ionblox has invented a clever way to mitigate these problems - a goal that many other battery startups are aspiring towards. But, in the context of achieving a high aviation safety standard, I wonder if it is pragmatic to use novel batteries in a novel propulsion system as part of a novel aircraft concept? I think that's a risk any observer has to assess for him or herself, weighing it against the potential upsides. Best wishes, John
I don't see any justification for the assumption at 7:38 that Archer's front and rear rotors are required to produce the same lift force. If the centre of mass is closer to the front row of rotors than the rear, which is likely, the front rotors will need to produce more lift.
Hi Brian, I assumed that the front and rear rotors need to generate the same lifting force for two reasons: 1) The position of the center of mass can be estimated from the wing. Its longitudinal position is usually around 1/4 of the chord length from the wing's leading edge. Once I positioned the center of mass, I can then look at how far away it is from the propulsion units. To me, the front and rear distances were more or less the same lengths, so that is why I assumed the front and rear rotors were required to produce the same lift force. 2) As Archer's engineer explained, they wanted to keep design commonality between the front and rear motors. Hence, my guess is that the motors would be sized for similar power requirements, but they could have different gear ratios. This design approach would make the most sense to me. Hope this helped! Best, John
Why would the graphic ask "are there 6 or 12 gearboxes" in the Archer design? Since the Archer presentation clearly implied a 6:1 reduction gear ratio, the rear rotors clearly cannot be effectively driven without reduction gearing - the torque to the rotor would be far too low.
This is the difference between a company that designs and manufacturers their own parts, and one that uses off the shelf parts then modifies them for the application.
Some quick back of the napkin ChatGPTing to lift a 4,400lbs load, about that of a kia optima fully loaded, as one could very likely be in a quad rotor config: Summary of Rotor Critical Dimensions and Characteristics: Diameter: 2.83 meters Number of Blades: 3 Blade Profile: NACA 4412 airfoil Chord Length: 0.1 meters at tip, 0.2 meters at root Blade Twist: 20 degrees at root, 10 degrees at tip Material: Carbon fiber/composite Blade Thickness: 12-15% at root, 6-8% at tip Rotation Speed: 2,000-3,000 RPM total power in the neighborhood of 400hp Now, sure, I havent checked any of these numbers....but anyone caring to poopoo them, you better provide yours otherwise your comment holds no more water than mine (and I cant believe that needs to be said, but STEM didnt make us smarter, so here we are).....So.....how are they gonna rewrite physics for this? running on big heavy batteries....since a combustion engines exhaust is 'inefficient waste heat'.... Btw, notice how much 'if' is in this presentation? Also, torque is a sub unit of power. So "increasing power AND torque densities" doesnt make as much sense as the buzzword blinded may think....
I imagine sometimes between 1910 and 1920 a lot of aircraft designers (if they would have had RUclips) would have wasted countless of hours talking about how the different time of harvesting hey straws that were used for the pilot seats would have had major impact in the weight reduction and how the wet season can affect the strength and weight of the wood used to build the wing frame. All interesting zoomed in details. But... now we know all that would be just useless talk around micromanaging in hope of inches of progress in a field limited by one single factor - available power. The only think that really matter in aviation at that moment was the fact that people understood 1. that birds are heavier than air thus heavier than air machines are actually going to be able to fly and 2. Flying opens up vastly new possibilities. As power and control availability increased during the aviation developing years for many it became evident that some things that are "sine qua non" necessities of flight are not really so... like wings and propellers and runways for take off and then gasoline tanks etc. They were just tools and the basic principle of flight being travel by not dragging or tumbling across the land of some sorts. If this would end up being done by pure magic - so be it. After 1980s it had became evident that power started to be available in big quantities. Small engines of 2000HP and more were becoming banalities. After 1990s it had become evident the control possibilities will become endless also. And since control was done electrically and available electrical power was also on the rise it was just normal to think about electrically driven VTOLs. There was just one little problem left... energy storage. And this problem still is. And all these marvelous hay sniffing propeller and engine shuffling is just time wasting as the drying plywood was back in the day on the long run. At this point because of this huge micromanagement and huge sums of money thrown into it people in the field seems to be lost the purpose. Like the Lilium team. They all started with the idea of "democratizing flight" and when they hit the hardship they all run to the closest banker to be showered in cheap money and all embraced desperately the idea that the few rich that want to fly from Nice to Monaco in a chopper will die of emotion to fly a "phantom 4 drone". It's one of the old problems of losing sight of the real resource. The real resource is not money but people and available technology and if things don't work yet don't just throw money but increase those resources instead. What is needed are more people (a gazillion lot more) involved and more battery energy density - which translates also in more people working on it. Not more money. Not more gimmicks that involve attracting more exclusive money. The results are evident - all these people have to show are silly expensive electric helicopters with swooshy wings that economically are useless in contest with the existing planes and helicopters - not only are hugely expensive to develop and produce but in the end they do the same job as a helicopter or plane and will be crushed by them because they never dared going outside their "kil-box" - the economic-legal kill box. For me... watching these developments is like watching a train wreck in slow motion.
Hi there! Yes, this is the second upload. I found the audio on my first attempt to be too quiet, so I went back to video editing and turned up the entire volume level. Hopefully, the audio is now more audible and in line with other RUclips videos now!
Archer is very focussed on redundancy for safety and their presentation was very open. More motors means more weight. It appears that both companies chose the wrong motor!
I just checked h3x, including their latest megawatt class aircraft application. Those are great motors but keep in mind that they are only great for aircraft (or maybe boat) companies that prefer a less integrated approach. Because H3X is not a propeller or turbine blade or water impeller company so they are not responsible for handling aerodynamic and hydrodynamic loads on the spinning body. Another way to think about it is: in both EV and combustion cars, a lot of road loads go through the suspension system and vehicle chassis without being dumped onto the engine or electric motor. To use H3X's motor, a less integrated aircraft have to re-route the propeller load (or any large spinning body) elsewhere (separate structure, additional mass) to protect the motor. Aircraft companies that decide to design and build their own motor optimized for their own aircraft can sometimes choose to let the load go through the electric motor's structure instead. A motor company's business model usually focus on packaging their product to provide convivence to many audiences while a motor developed by an aircraft company focus on designing motor specifically for their own aircraft without worrying how their motor fit into the market. If one were to start up a car company with hub/wheel motor at each wheel, the founder will not use Lucid or Tesla electric motor even if the founder receives motors from these two brands for free.
While "motor" is the current conventional word usage, "engine" is also technically correct. They must be aware that "motor" is conventional; I'm not sure why they consciously chose "engine", but it may be for familiarity in the aviation world.
Driving mechanism is identified as engine...it may either be powered by gasoline called as ICE - Internal Combustion Engines or battery 🔋 powered motors
Neither makes their own batteries. They could use batteries from a variety of suppliers. Batteries will be upgraded as battery tech improves just as it has in EVs.
This video has a lot of good information and data, however, the constant use of "rotor" where it should be " propeller" makes one question the validity of the rest of the data. These props are either constant speed (collective pitch only) or fixed pitch. There was not "cycle" control introduced in the video, which would be a characteristic of a rotor..
They're still rotors, even without cyclic pitch control. The tail rotor of a conventional helicopter has collective but not cyclic pitch control... and it's a *rotor*
They don't have special motors that other people couldn't make without licensing. There isn't an experimental market. There are scam startups and they will not sell their insufficient components and blow the whole scam.
A good comparison but limited first by the accuracy and honesty of the respective firms data. there has to be a major flaw in the calculation for Joby hover power (cited as '100 kw" -that is only 134 HP , and the basic idea that much less power is going to be used in hover than in wing borne flight is just wrong ( I suspect a decimal point problem -ie 1000 kw in hover perhaps -the level flight L/D might be around 15 or more and hovering requires thrust equal to weight with at least a 25% margin to get some useful work to climb and accelerate -plus a further margin to cover an engine failure (doubled to maintain thrust symmetry --more in the case of Joby which loses 1/3 of power or thrust versus 1/6 for Archer ) Whether peak power IS acheived at peak torque (never the case with ICE) is another questionable assumption - and the use of "continuous' torque rather than "peak" torque at this critical case seems in error - you need all the horses pulling as hard as possible in take off and vertical landing - less so in cruise. (MUCH less -this is the first Achilles heel for 'e' VTOL since the power is sized for the hover/climb and too much and too heavy in cruise . We need partial power figures rather than max everything but I realize that they are not publishing real engineering papers (No SAE etc and the latest Janes's is just advertising fluff ) -a critique is handicapped by the secrecy and disinformation put out. There is something amiss with Gudrunson's thrust curves --all reaching zero thrust at 250 is a bit strange -- without knowing the variables and constants it cannot be evaluated -- the eVTOL case needs as much blade area and disc area as feasible --with the rear props being fixed pitch (even if 'clocking' to fold flat in cruise as for VX4 ) they are going to be woeful in transition and in the wake of the front props -- a dog's breakfast of turbulent air and 'non optimum' orientaion etc -- how they expect to 'balance' a variable pitch five blade front prop with a fixed pitch rear prop in the 'engine out' case is a mystery - it has to be by software manipulation a la 737 Max MCAS..... how many failure modes are there ? Joby bad mouthing planetary gearboxes is a bit rich -just about every automatic car has multiple planetary (even the model T...) and smooth electric power is the ideal case -- again, propaganda aimed at Archer - both of them are like two bald men fighting over a comb in any case --the diseconomies and failings of the whole eVTOL fiasco are yet to play out ( I just purchsed some 1940s and 50s "Aeroplane' and "Aircraft Engineering " Aircraft Production " magazines at the local flea market and it is interesting to see the arguments for and against the huge passenger flying boat playing out on their pages together with pictures of the HUGE Saunders Roe Princess flying boats (they built THREE simultaneously so confident were they -none ever served..) the gigantic Hughes (Hercules) flying boat and the Bristol Brabazon are other examples of irrational exuberance and folly -literally dwarfing the current eVTOL madness but a similar affliction. Look behind the curtain. PS I will do a better analysis as time permits.
Hey Ross, glad to see you back 😃! So for the hover power at 15:22 I meant the required power per rotor during hover flight. For the entire aircraft, I estimated a hover power of 600kW using a MTOW of 2700kg and a figure of merit of 0.7. On this slide, I wanted to estimate the blade tip speed during hover flight, so I started with an assumption for the power per rotor. Joby has six propulsion units, so the power per rotor during hover flight would be 100kW. (I should have probably not called it 'hover power' and just gone for the more wordy term). From what I have seen, peak power approximately occurs at peak torque. For example, take a look at this data, which closely matches Joby's needs: evolito.aero/media/2023/09/Evolito-D1500-2x3-Datasheet-V2.pdf For some motors, you can get more torque by sacrificing rotational speed and power. In terms of sizing the propulsion system, I reasoned that the motor's peak power is matched with a scenario where one rotor is inoperative, and another rotor is throttled down to trim the aircraft. The propulsion system's continuous power is matched with nominal take-off. I did not like the idea of matching peak power with nominal take-off. I could be wrong on the points above and would be eager to be corrected and learn! Best, John
OK that seems a bit closer to reality ( I did consider if it was per rotor but that seemed a bit too low in total --the Lilium hover power still takes the cake for overkill , I'll take a look at your link in the morning (near midnight here --- no pun intended !) I just did my usual IN sanity check of the VFS register and note the latest entry is a virtual Joby clone from China but with the difference that the two inner front rotors are NOT tilters but fixed horizontal lifters that stop and fair fore and aft in cruise -this relieves those two tractor rotors in cruise on Joby and will help with the excessive blade area in cruise (Mark Moore and Joby itself pointed out the poor cruise efficiency with using all lift rotors as propellers in their S2 dissertation then convenientkly forgot that with S4 .... Those tilting hinges are obvious weak points and more so on Archer or Wisk or VZ4 et al --the destruction of the VX4 following blade assymetry (as predicted) shows this flaw - propeller whirl flutter caused catastrophic failures on the Lockheed Electra for the same root cause and is lurking still (blade icing etc can trigger it with those spindly booms on Midnight in particular - much more prone than VX4 . As to accounting for an 'inoperative' proprotor -- such 'inoperation' might well be instantaneous and total requiring full 'throttle down' on the corresponding 'good' prop -- runaway pich control has been a failure mode on earlier VTOL eg Curtiss X 19 Dynavert et al and actuator failure (tilters included) or resultant assymetry particularly in transition would be interesting (those hordes of fresh faced grads peering intently into screens on their promos have to be doing something -- this is much more accident prone than the model quadcopter case with extremely low inertias and rate gyros as the front line stability . more soon , cheers Ross . ATOL is the way.😋@@zhihenglou
Peak power and peak torque _can_ occur at the same speed for an internal combustion engine, but only if the engine speed is limited (typically for fuel economy or reliability reasons) to that value. For instance, the 7.3 L gas engine in a Ford F-650 is rated at 468 lb.-ft. of torque and 335 HP, both at 3,750 RPM; the same engine in a much lighter-duty Ford F-350 can produce a similar 485 lb.-ft. of torque at 4,000 rpm, but is allowed to turn faster to produce up to 430 horsepower at 5,500 rpm.
@@zhihenglouelectric motor peak torque occurs at zero speed, and from there up to the point that the motor and controller are no longer current-limited. Peak power speed depends on multiple factors including heat management and available drive voltage. In a typical automotive application, peak motor power is limited by the controller - not the motor itself - and the controller "cuts the top off of the power curve", so the same power is available all the way from about the speed where current is no longer the limit (e.g. about 2,700 RPM for a Nissan Leaf) to the point that voltage is the limiting factor (about 10,500 RPM for the same Nissan Leaf), with more speed allowed with lower torque (up to about 12,000 RPM for the Leaf). Since electric motors for aircraft don't need a wide speed range, in direct-drive applications they are typically designed to operate in a narrow speed range not far above the current-limited speed (so a Leaf motor would be used at about 3,000 RPM; other EV motors might have substantially higher corresponding speeds).
Pretty bad when people correct other people who are not wrong. Go to a dictionary such as Merriam-Webster (presumably online, but the still print them) and look at the definitions of the two words.
@BlueEyed888 no matter how they design the motor or how light it is the battery weight will keep them from being able to lift a load that matters and move it a distance that matters. The whole industry is nothing but a scam.
Great video. Thankyou. Archer does admit the Midnight is not the best eVTOL out there. They just want to fast track something that gets to market.
Joby are years ahead with their research and development, and way ahead with FAA cert testing.
Nov 6th 2024, Joby Aviation (NYSE:JOBY) is 41% through Stage 4 FAA cert testing, expecting FAA certification in 2025.
Cash position:
$710m plus the following to be added:
PLUS Early October 2024, Toyota made an agreement to invest a further $500m into Joby in 2025.
PLUS Late October 2024, Joby raised $230m. (less costs, call it $220m)
PLUS Delta Airlines will further invest up to $140m as milestones reached.
PLUS Saudi Arabia MOU for an undisclosed number of S4's - fast tracking income while air taxi builds out
PLUS $130m DoD contract.
PLUS Marina factory producing 12 eVTOLs per year expanding to 25 per year.
PLUS Dayton factory (my estimate of production ramping up) 2026: 150 eVTOLs 2027: 400 eVTOLs 2027: 500 eVTOLs.
So Joby has a huge cash runway (over $1.7 billion) plus up to $325 million in incentives and benefits. Within 2028 they will have more than 1000 eVTOLs producing cash.
Note: The state of Ohio and several political organizations have offered up to $325 million in incentives and benefits to develop the new Dayton factory, expected to be ready 2025.
Incentives include grants, tax credits, and infrastructure support, as well as workforce development assistance aimed at helping Joby hire and train approximately 2,000 employees for the factory.
My estimates for production: Cumulative values
2024 Marina 6 Dayton 0
2025 Marina 18 Dayton 0 (Dayton will be ready at this point)
2026 Marina 32 Dayton 150
2027 Marina 48 Dayton 550
2028 Marina 66 Dayton 1050
I have allowed ramp up for both Marina and Dayton. Total in 2028: 1116 eVTOLS.
"..A Joby Aviation S4 2.0 aircraft is projected to generate $2.2 million in annual revenue.." So from 2028 that is $2.45 billion earnings.
The average tech sector P/E ratio is 33, implying a market cap of $81 billion by then, or a share price of $106. The share price is currently $6.
Joby's vertical integration is its superpower.
Joby MTOW is 5300 lbs, Archer MTOW is 6700 lbs (same number of passengers). So Joby is more energy efficient.
Joby is faster at 200 mph.
Joby has longer flight duration which makes it more versatile.
Joby S4's first piloted flight September 2023. Archer have not yet piloted a flight. I suspect Archer could be a year behind with FAA cert.
Joby 41% through fourth stage (FAA testing) in Nov 6th 2024 report. Note in 2023 they obtained a clear path to certification of their pouch battery. Tail approval is highly significant - materials and structure.
Joby S4's hover noise is 67dBA, far quieter compared to Archer. Joby's on-wing flight 100 times quieter than a helicopter. For Archer, noise could be a big approval problem for operating in cities.
Both Archer and Joby have a former FAA administrator on the board.
Joby are producing pre-production prototypes as promised (4th being finalised, possibly 5th by end of 2024). There is no evidence of Archer rolling out prototypes. Indeed, Archer made the comment during 7th Nov report that they don't want to say when the test prototype (singular) will be ready because that would put undue pressure on the team - that's not good enough and leads to the question: are Archer potentially hiding something? It is the very essence of the company and Archer can't give an approximation?
Joby ditched gear boxes years ago. Their six direct drive motors are simpler, lighter, lower maintenance. Archer still on gear boxes. Archer's motors weigh 300Kg in total, Joby's total is 168Kg.
Joby has 10,000+ hours of flight data so far.
Joby will be first mover, its vertically integrated production cheaper, more reliable and more agile. It's aircraft weight, speed, duration and noise superior.
Just my thoughts. No investment advice given.
Thanks for the interesting write-up and analysis!
You mentioned that Joby’s on-wing flight is 100 times quieter than a helicopter. I would double-check this value because I think it is incorrect. Joby had stated this 100x quieter value several times, but it is not a fair description of the reduction in perceived loudness. For this reason, I would generally recommend everyone following the eVTOL industry to learn more about aircraft noise and aeroacoustics. Recently, I did a deep analysis on eVTOL noise, including a deep dive on Joby’s patents on noise optimizations.
You can watch the video here: ruclips.net/video/8BjlAqNz5QM/видео.htmlsi=Nr1BELUirDwKO6-v
Wow, where do you get most of your information? Are there similar aircrafts like Joby? Maybe with an additional fuel consumpting motor?
| References |
(Anton, 2019) www.bbaa.de/fileadmin/user_upload/02-preis/02-02-preistraeger/newsletter-2019/02-2019-09/02_Siemens_Anton.pdf
(Archer, 2022a) ruclips.net/video/PmRKdpIRg0w/видео.html
(Archer, 2022b) archer.com/news/what-is-urban-air-mobility
(Archer, 2022c) ruclips.net/video/z2UKGoly4X8/видео.html
(Archer, 2023) archer.com/news/stellantis-to-build-electric-aircraft-with-archer-and-provide-strategic-funding-for-growth
(AvBuyer, 2023) www.avbuyer.com/articles/ga-buyer-europe/what-to-know-siemens-hybrid-electric-propulsion-systems-112417
(AviationWeek, 2021) aviationweek.com/aerospace/urban-unmanned-aviation/archers-evtol-designed-early-market-entry
(EASA, 2020) www.easa.europa.eu/en/downloads/114474/en
(Electric VTOL News, 2022a) evtol.news/news/new-evtol-galleries
(Electric VTOL News, 2022b) evtol.news/news/jobys-patents-reveal-new-details
(Emobility-engineering, 2023) www.emobility-engineering.com/magnix-magni350-650-and-magnidrive-100/
(EMRAX, 2019) emrax.com/e-motors/emrax-268/
(Evolito, 2023) evolito.aero/media/2023/09/Evolito-D1500-2x3-Datasheet-V2.pdf
(Flyer, 2020) flyer.co.uk/pipistrel-offers-type-certified-electric-motor-to-others/
(Gudmundsson, 2022) www.sciencedirect.com/book/9780128184653/general-aviation-aircraft-design
(Joby, 2023a) ruclips.net/video/q9-BwRWHa0I/видео.html
(Joby, 2023b) twitter.com/jobyaviation/status/1678771583475929089
(NASA, 2022) www1.grc.nasa.gov/beginners-guide-to-aeronautics/size-effects-on-drag/
(Safran, 2023) www.safran-group.com/products-services/engineustm
(Shankland, 2022) www.cnet.com/roadshow/news/archer-reveals-its-electric-air-taxi-for-10-minute-flights-to-the-airport/
(Stoll, 2015) nari.arc.nasa.gov/sites/default/files/attachments/Stoll-TVFW-Aug2015.pdf
(The Air Current, 2023) ruclips.net/video/3UxrchnefOs/видео.html
(VFS, 2022) gallery.vtol.org/image/1D6eX
Many thanks for your detailed breakdown John. Your knowledge and expertise is obvious and appreciated.
Great analysis. You validated my points I’ve been saying about Archer as Joby seems to be the winner when compared against each other. I believe the drag of the rear motors and extra weight alone is enough to rule out archer. I have never seen a full transition of flight in any released video from archer. Which been a RED flag for me as I do like there cockpit design but see many negative factors to their design choice and choice to use a gearbox. I have some electric motor experience since 2005 and I can tell you, a gear box is a negative for electric motors as those gears will need constant maintenance and eventually a full replacement.
You talked about the structure of some motors, which is very interesting, but the most important parameters of the motor are still efficiency. Efficiency determines the life of the motor. Of course, it is necessary to understand this concept.
Great videos, John. I'd love to see a high level video on what architectures you think are best for different business models. Also love to get your thoughts on Overair's butterfly
Boy this is a great video! I'm hopefully that eVTOLs will soon be flying commercial routes. But as this video makes clear there are huge engineering challenges involved. If you listen to these companies spokespersons, they are all also clear that they hope to achieve some level of autonomous flight. I wonder which company is the furthest along in flight automation?
Thanks for that very detailed expose, John. Very helpful.
Very much thanks to you，this article very important meaning
to my design.Archer and Joby who both my reference make my design more clearly
Excellent video and analysis. I was for both, you can see me in them. And it's uncanny how different both companies are and still share similarities. I'll update my article to include your link. Spot on!
I’m also interested to see how both compare in noise levels. Nasa did acoustic testing back in 2022 for Joby. Very impressive stats for Joby especially when compared to many other aircrafts. I haven’t seen any acoustic validation for Archer yet. Would love to see Archer’s and how they compare at take off/ landing and full transition flight.
ruclips.net/video/FFguE2qWPfk/видео.htmlsi=kUZCFAIj_6HKTHko
Archer aviation will be more noisy.
But Archer in my opinion safer due to
12 propellor
Excellent analysis videos, like the other ones on your channel. Really informative.
Based on your previous videos comparing propulsions of Joby Aviation and Vertical Aerospace, and now the comparision between motors of Archer and Joby, I wonder what you think about Alia eVTOL by Beta and where it fits along with the other three.
Hi there!
I think Beta's Alia eVTOL is a simpler design, so it could get certified and come to the market first. However, this advantage could be temporary, as it depends on the certification of eVTOL aircraft with better performance. On the other hand, other eVTOL aircraft may not get certified at all. So, I think Beta's eVTOL is a product with lower risk but also lower potential.
Best,
John
@@zhihenglou Hmm, interesting point. Thanks
Flying the BETA without lift props is significant - it makes a mockery of the wing booms and weird ultra swept tail though --their props are also 'unusual' and unlikely to be efficient (2 blade scimitars ) --the sheer SIZE of these monsters is only apparent when somone walks under a wing with a foot or more to spare --and these are only four seaters (the other dozen or so 'stowaways' are in the battery compartment ...)
What do you think about the 28kg weight of the motor and inverter combined? Do you think that includes the weight of Thermal management system, coolant, housing, the additional devices to withstand the mechanical load (like a bearing)?
The speaker at the Joby presentation mentioned that their direct drive motor had been patented. I imagine you could perhaps answer some of your questions about it, if you were able to find that patent. I did some brief searching online, but the closest thing I found was a Joby patent on Justia for an "Aircraft propulsion unit." This doesn't seem to be for the motor itself. Perhaps the patent has been filed, but not published, yet? Or I just wasn't looking in the right place....
That guy was a charlatan
Again, great content, thanks!
Interesting how the leading companies with such similar design requirements comes to two completely different conclusions.
Jobys numbers sure seem to good to be true, I do hope they match reality, that would be great for the development of all future electric manned flight vehicles! Time will tell.
I like the idea of dual winding (split stator?). If the dual winding also comes with dual esc, that might provide a sort of esc-motor redundancy within a single motor housing.
Kind regards/Axel
Hey Axel, great to see you again :)!
Thanks again, fascinated to see the gen 2 VX4 aft rotors at work and in transition! With any luck that will be early - mid 2024. Also, if I could request more VX4 content, I would appreciate it!
Hi Harry! Sure, I'll keep that in mind! I haven't found a lot of public data on the VX4 yet, but I'm eager to report on them, too😄
Thank you for yet another great analysis! I really enjoy your in-depth videos. I'm really curious to hear, did you see Liliums recent battery webinar, and what did you think of it?
Hi!
I'm glad you like these kinds of videos; thank you for your viewership!
Yes, I've seen Lilium's recent battery webinar. Overall, I think it's an excellent presentation with clear and concise explanations. And it's positive to see Lilium's leadership team address some of the industry's concerns and engage with the public. However, in terms of content, I haven't seen anything in the presentation that would change my previous conclusion.
Information about Lilium's batteries was already released more than a year ago (e.g., lilium.com/newsroom-detail/liliums-battery-strategy), so the battery webinar didn't bring new perspectives in this regard. Whilst batteries with high silicon content in their anodes can have outstanding performance, their adoption has been historically limited by numerous problems. I imagine Ionblox has invented a clever way to mitigate these problems - a goal that many other battery startups are aspiring towards. But, in the context of achieving a high aviation safety standard, I wonder if it is pragmatic to use novel batteries in a novel propulsion system as part of a novel aircraft concept?
I think that's a risk any observer has to assess for him or herself, weighing it against the potential upsides.
Best wishes,
John
Joby’s motor may be a six phase which they are calling to separate Motors to double the horsepower in the same package with six faces versus three
Thanks for your detail video, that's really helpful. I just wonder how could you get the conclusion that Joby is using an axial flux design?
I don't see any justification for the assumption at 7:38 that Archer's front and rear rotors are required to produce the same lift force. If the centre of mass is closer to the front row of rotors than the rear, which is likely, the front rotors will need to produce more lift.
Hi Brian,
I assumed that the front and rear rotors need to generate the same lifting force for two reasons:
1) The position of the center of mass can be estimated from the wing. Its longitudinal position is usually around 1/4 of the chord length from the wing's leading edge. Once I positioned the center of mass, I can then look at how far away it is from the propulsion units. To me, the front and rear distances were more or less the same lengths, so that is why I assumed the front and rear rotors were required to produce the same lift force.
2) As Archer's engineer explained, they wanted to keep design commonality between the front and rear motors. Hence, my guess is that the motors would be sized for similar power requirements, but they could have different gear ratios. This design approach would make the most sense to me.
Hope this helped!
Best,
John
Cooling is a critical factor. How do each of this companies cool their motors.
fantastic video
Which one has less noise during vertical takeoff, transition and flight?
Why would the graphic ask "are there 6 or 12 gearboxes" in the Archer design? Since the Archer presentation clearly implied a 6:1 reduction gear ratio, the rear rotors clearly cannot be effectively driven without reduction gearing - the torque to the rotor would be far too low.
This is the difference between a company that designs and manufacturers their own parts, and one that uses off the shelf parts then modifies them for the application.
however the manufacturing costs of both have not been discussed.
@MildlyCurious Joby is working on manufacturing processes and though costs will be high, so will demand for the S4.
Some quick back of the napkin ChatGPTing to lift a 4,400lbs load, about that of a kia optima fully loaded, as one could very likely be in a quad rotor config:
Summary of Rotor Critical Dimensions and Characteristics:
Diameter: 2.83 meters
Number of Blades: 3
Blade Profile: NACA 4412 airfoil
Chord Length: 0.1 meters at tip, 0.2 meters at root
Blade Twist: 20 degrees at root, 10 degrees at tip
Material: Carbon fiber/composite
Blade Thickness: 12-15% at root, 6-8% at tip
Rotation Speed: 2,000-3,000 RPM
total power in the neighborhood of 400hp
Now, sure, I havent checked any of these numbers....but anyone caring to poopoo them, you better provide yours otherwise your comment holds no more water than mine (and I cant believe that needs to be said, but STEM didnt make us smarter, so here we are).....So.....how are they gonna rewrite physics for this? running on big heavy batteries....since a combustion engines exhaust is 'inefficient waste heat'....
Btw, notice how much 'if' is in this presentation? Also, torque is a sub unit of power. So "increasing power AND torque densities" doesnt make as much sense as the buzzword blinded may think....
I imagine sometimes between 1910 and 1920 a lot of aircraft designers (if they would have had RUclips) would have wasted countless of hours talking about how the different time of harvesting hey straws that were used for the pilot seats would have had major impact in the weight reduction and how the wet season can affect the strength and weight of the wood used to build the wing frame. All interesting zoomed in details. But... now we know all that would be just useless talk around micromanaging in hope of inches of progress in a field limited by one single factor - available power.
The only think that really matter in aviation at that moment was the fact that people understood 1. that birds are heavier than air thus heavier than air machines are actually going to be able to fly and 2. Flying opens up vastly new possibilities.
As power and control availability increased during the aviation developing years for many it became evident that some things that are "sine qua non" necessities of flight are not really so... like wings and propellers and runways for take off and then gasoline tanks etc. They were just tools and the basic principle of flight being travel by not dragging or tumbling across the land of some sorts. If this would end up being done by pure magic - so be it.
After 1980s it had became evident that power started to be available in big quantities. Small engines of 2000HP and more were becoming banalities. After 1990s it had become evident the control possibilities will become endless also.
And since control was done electrically and available electrical power was also on the rise it was just normal to think about electrically driven VTOLs.
There was just one little problem left... energy storage. And this problem still is. And all these marvelous hay sniffing propeller and engine shuffling is just time wasting as the drying plywood was back in the day on the long run.
At this point because of this huge micromanagement and huge sums of money thrown into it people in the field seems to be lost the purpose. Like the Lilium team. They all started with the idea of "democratizing flight" and when they hit the hardship they all run to the closest banker to be showered in cheap money and all embraced desperately the idea that the few rich that want to fly from Nice to Monaco in a chopper will die of emotion to fly a "phantom 4 drone". It's one of the old problems of losing sight of the real resource. The real resource is not money but people and available technology and if things don't work yet don't just throw money but increase those resources instead.
What is needed are more people (a gazillion lot more) involved and more battery energy density - which translates also in more people working on it. Not more money. Not more gimmicks that involve attracting more exclusive money.
The results are evident - all these people have to show are silly expensive electric helicopters with swooshy wings that economically are useless in contest with the existing planes and helicopters - not only are hugely expensive to develop and produce but in the end they do the same job as a helicopter or plane and will be crushed by them because they never dared going outside their "kil-box" - the economic-legal kill box.
For me... watching these developments is like watching a train wreck in slow motion.
I have archer joby lilium evtl and evex❤
❤ for me its nice to both are in servece 2:14
Do you invest in any of these companies?
I have a JOBY position
please do more videos
I wonder what was the reason for re-uploading this video twice. I suppose you found some mistakes and wanted to have maximal informational accuracy?
Hi there! Yes, this is the second upload. I found the audio on my first attempt to be too quiet, so I went back to video editing and turned up the entire volume level. Hopefully, the audio is now more audible and in line with other RUclips videos now!
It's loud engouh,@@zhihenglou , but your narration is so muffled it sounds like you are speaking through a barrier of rubber foam.
수치로 비교하면 정확하지만 저처럼 비 전문가입장에서 볼때는 아처 미드나잇 기체 프로펠러 숫자 9개 조비 s4기체 프로펠러 6개 ... 이것만 봐도 조비 모터가 더 힘이 쎄다는걸 추측해봅니다...
Archer is very focussed on redundancy for safety and their presentation was very open. More motors means more weight. It appears that both companies chose the wrong motor!
Are you familiar with h3x and their claim of 12,5kW/kg?
I just checked h3x, including their latest megawatt class aircraft application. Those are great motors but keep in mind that they are only great for aircraft (or maybe boat) companies that prefer a less integrated approach. Because H3X is not a propeller or turbine blade or water impeller company so they are not responsible for handling aerodynamic and hydrodynamic loads on the spinning body. Another way to think about it is: in both EV and combustion cars, a lot of road loads go through the suspension system and vehicle chassis without being dumped onto the engine or electric motor. To use H3X's motor, a less integrated aircraft have to re-route the propeller load (or any large spinning body) elsewhere (separate structure, additional mass) to protect the motor. Aircraft companies that decide to design and build their own motor optimized for their own aircraft can sometimes choose to let the load go through the electric motor's structure instead. A motor company's business model usually focus on packaging their product to provide convivence to many audiences while a motor developed by an aircraft company focus on designing motor specifically for their own aircraft without worrying how their motor fit into the market. If one were to start up a car company with hub/wheel motor at each wheel, the founder will not use Lucid or Tesla electric motor even if the founder receives motors from these two brands for free.
it's odd how archer is calling motors engines. These are definately electric motors...no need to try to call them something else.
At least they don't call them electric jet engines
While "motor" is the current conventional word usage, "engine" is also technically correct. They must be aware that "motor" is conventional; I'm not sure why they consciously chose "engine", but it may be for familiarity in the aviation world.
Its marketing, for common people to easily understand.
“Engine” is correct with respect to the systems engineering of the vehicle. Uninstall it, and the “engine” is an electric motor.
Driving mechanism is identified as engine...it may either be powered by gasoline called as ICE - Internal Combustion Engines or battery 🔋 powered motors
Lilium ❤️🚀🚀🚀🚀
The real question is, "Who has the best battery?"
Neither makes their own batteries. They could use batteries from a variety of suppliers. Batteries will be upgraded as battery tech improves just as it has in EVs.
I’m a pilot, and I believe that Archer has a design flaw which is going to come back to be their ruin.
could you share what that might be?
This video has a lot of good information and data, however, the constant use of "rotor" where it should be " propeller" makes one question the validity of the rest of the data. These props are either constant speed (collective pitch only) or fixed pitch. There was not "cycle" control introduced in the video, which would be a characteristic of a rotor..
mutli rotor evtols
NO! Multi Prop eVTOL . . @@TheBagOfHolding
They're still rotors, even without cyclic pitch control. The tail rotor of a conventional helicopter has collective but not cyclic pitch control... and it's a *rotor*
Its realy needed a quit 18:58
Now if Joby wants to generate some now cash, sell some motor and systems to the Experimental market.
They don't have special motors that other people couldn't make without licensing. There isn't an experimental market. There are scam startups and they will not sell their insufficient components and blow the whole scam.
A good comparison but limited first by the accuracy and honesty of the respective firms data. there has to be a major flaw in the calculation for Joby hover power (cited as '100 kw" -that is only 134 HP , and the basic idea that much less power is going to be used in hover than in wing borne flight is just wrong ( I suspect a decimal point problem -ie 1000 kw in hover perhaps -the level flight L/D might be around 15 or more and hovering requires thrust equal to weight with at least a 25% margin to get some useful work to climb and accelerate -plus a further margin to cover an engine failure (doubled to maintain thrust symmetry --more in the case of Joby which loses 1/3 of power or thrust versus 1/6 for Archer )
Whether peak power IS acheived at peak torque (never the case with ICE) is another questionable assumption - and the use of "continuous' torque rather than "peak" torque at this critical case seems in error - you need all the horses pulling as hard as possible in take off and vertical landing - less so in cruise. (MUCH less -this is the first Achilles heel for 'e' VTOL since the power is sized for the hover/climb and too much and too heavy in cruise . We need partial power figures rather than max everything but I realize that they are not publishing real engineering papers (No SAE etc and the latest Janes's is just advertising fluff ) -a critique is handicapped by the secrecy and disinformation put out.
There is something amiss with Gudrunson's thrust curves --all reaching zero thrust at 250 is a bit strange -- without knowing the variables and constants it cannot be evaluated -- the eVTOL case needs as much blade area and disc area as feasible --with the rear props being fixed pitch (even if 'clocking' to fold flat in cruise as for VX4 ) they are going to be woeful in transition and in the wake of the front props -- a dog's breakfast of turbulent air and 'non optimum' orientaion etc -- how they expect to 'balance' a variable pitch five blade front prop with a fixed pitch rear prop in the 'engine out' case is a mystery - it has to be by software manipulation a la 737 Max MCAS..... how many failure modes are there ?
Joby bad mouthing planetary gearboxes is a bit rich -just about every automatic car has multiple planetary (even the model T...) and smooth electric power is the ideal case -- again, propaganda aimed at Archer - both of them are like two bald men fighting over a comb in any case --the diseconomies and failings of the whole eVTOL fiasco are yet to play out ( I just purchsed some 1940s and 50s "Aeroplane' and "Aircraft Engineering " Aircraft Production " magazines at the local flea market and it is interesting to see the arguments for and against the huge passenger flying boat playing out on their pages together with pictures of the HUGE Saunders Roe Princess flying boats (they built THREE simultaneously so confident were they -none ever served..) the gigantic Hughes (Hercules) flying boat and the Bristol Brabazon are other examples of irrational exuberance and folly -literally dwarfing the current eVTOL madness but a similar affliction. Look behind the curtain. PS I will do a better analysis as time permits.
The cross outs are some computer glitch -not intentional,sorry
Hey Ross, glad to see you back 😃!
So for the hover power at 15:22 I meant the required power per rotor during hover flight. For the entire aircraft, I estimated a hover power of 600kW using a MTOW of 2700kg and a figure of merit of 0.7. On this slide, I wanted to estimate the blade tip speed during hover flight, so I started with an assumption for the power per rotor. Joby has six propulsion units, so the power per rotor during hover flight would be 100kW. (I should have probably not called it 'hover power' and just gone for the more wordy term).
From what I have seen, peak power approximately occurs at peak torque. For example, take a look at this data, which closely matches Joby's needs: evolito.aero/media/2023/09/Evolito-D1500-2x3-Datasheet-V2.pdf
For some motors, you can get more torque by sacrificing rotational speed and power.
In terms of sizing the propulsion system, I reasoned that the motor's peak power is matched with a scenario where one rotor is inoperative, and another rotor is throttled down to trim the aircraft. The propulsion system's continuous power is matched with nominal take-off. I did not like the idea of matching peak power with nominal take-off.
I could be wrong on the points above and would be eager to be corrected and learn!
Best,
John
OK that seems a bit closer to reality ( I did consider if it was per rotor but that seemed a bit too low in total --the Lilium hover power still takes the cake for overkill , I'll take a look at your link in the morning (near midnight here --- no pun intended !) I just did my usual IN sanity check of the VFS register and note the latest entry is a virtual Joby clone from China but with the difference that the two inner front rotors are NOT tilters but fixed horizontal lifters that stop and fair fore and aft in cruise -this relieves those two tractor rotors in cruise on Joby and will help with the excessive blade area in cruise (Mark Moore and Joby itself pointed out the poor cruise efficiency with using all lift rotors as propellers in their S2 dissertation then convenientkly forgot that with S4 .... Those tilting hinges are obvious weak points and more so on Archer or Wisk or VZ4 et al --the destruction of the VX4 following blade assymetry (as predicted) shows this flaw - propeller whirl flutter caused catastrophic failures on the Lockheed Electra for the same root cause and is lurking still (blade icing etc can trigger it with those spindly booms on Midnight in particular - much more prone than VX4 . As to accounting for an 'inoperative' proprotor -- such 'inoperation' might well be instantaneous and total requiring full 'throttle down' on the corresponding 'good' prop -- runaway pich control has been a failure mode on earlier VTOL eg Curtiss X 19 Dynavert et al and actuator failure (tilters included) or resultant assymetry particularly in transition would be interesting (those hordes of fresh faced grads peering intently into screens on their promos have to be doing something -- this is much more accident prone than the model quadcopter case with extremely low inertias and rate gyros as the front line stability . more soon , cheers Ross . ATOL is the way.😋@@zhihenglou
Peak power and peak torque _can_ occur at the same speed for an internal combustion engine, but only if the engine speed is limited (typically for fuel economy or reliability reasons) to that value. For instance, the 7.3 L gas engine in a Ford F-650 is rated at 468 lb.-ft. of torque and 335 HP, both at 3,750 RPM; the same engine in a much lighter-duty Ford F-350 can produce a similar 485 lb.-ft. of torque at 4,000 rpm, but is allowed to turn faster to produce up to 430 horsepower at 5,500 rpm.
@@zhihenglouelectric motor peak torque occurs at zero speed, and from there up to the point that the motor and controller are no longer current-limited. Peak power speed depends on multiple factors including heat management and available drive voltage. In a typical automotive application, peak motor power is limited by the controller - not the motor itself - and the controller "cuts the top off of the power curve", so the same power is available all the way from about the speed where current is no longer the limit (e.g. about 2,700 RPM for a Nissan Leaf) to the point that voltage is the limiting factor (about 10,500 RPM for the same Nissan Leaf), with more speed allowed with lower torque (up to about 12,000 RPM for the Leaf). Since electric motors for aircraft don't need a wide speed range, in direct-drive applications they are typically designed to operate in a narrow speed range not far above the current-limited speed (so a Leaf motor would be used at about 3,000 RPM; other EV motors might have substantially higher corresponding speeds).
The narrator's audio is really muffled - not low in level, but not clear.
I have designed better motors, jet engines, and rocket engines along with a bibliography of technical sources.
At 1:18 -- they're not engines! They're motors. Dumschittz.
Pretty bad when your engineer does not know the difference between an engine and a motor.
Pretty bad when people correct other people who are not wrong. Go to a dictionary such as Merriam-Webster (presumably online, but the still print them) and look at the definitions of the two words.
I don't even think motors matter at all. Its all about the battery. Thats why they are all bunk.
Everything matters, but I agree that at this point battery weight is more important than motor weight.
Weight and efficiency of the motors don’t matter? Of course those affect range which is crucial.
@BlueEyed888 no matter how they design the motor or how light it is the battery weight will keep them from being able to lift a load that matters and move it a distance that matters. The whole industry is nothing but a scam.