- Видео 5
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John Lou
Великобритания
Добавлен 14 фев 2018
Drones | Electric aircraft | Hydrogen aircraft
EVTOL Noise: What's Possible? What's Hype?
| Description |
Leading eVTOL companies claim that their aircraft can be 10, 100, or even 1000 times quieter than conventional helicopters. Are such low noise levels possible in theory? And what progress has been made and demonstrated so far?
To answer these questions, this video reviews the science of sound waves and aircraft noise. It then discusses various noise reduction strategies by eVTOL companies, in particular, patents by Joby Aviation. Finally, noise claims by leading eVTOL companies are analyzed and assessed.
| Timestamps |
0:00 Introduction
1:44 Chapter 1: How do aircraft generate noise?
33:06 Chapter 2: How can eVTOL aircraft reduce noise?
53:47 Chapter 3: What is possible? What is ...
Leading eVTOL companies claim that their aircraft can be 10, 100, or even 1000 times quieter than conventional helicopters. Are such low noise levels possible in theory? And what progress has been made and demonstrated so far?
To answer these questions, this video reviews the science of sound waves and aircraft noise. It then discusses various noise reduction strategies by eVTOL companies, in particular, patents by Joby Aviation. Finally, noise claims by leading eVTOL companies are analyzed and assessed.
| Timestamps |
0:00 Introduction
1:44 Chapter 1: How do aircraft generate noise?
33:06 Chapter 2: How can eVTOL aircraft reduce noise?
53:47 Chapter 3: What is possible? What is ...
Просмотров: 3 560
Видео
Archer vs Joby: who has the better motor?
Просмотров 25 тыс.Год назад
| Description | This video examines the electric motors by Archer and Joby, the two frontrunners in the eVTOL industry. We start with a high-level analysis of their relative benefits and drawbacks, scoping our analysis to their torque and power densities. The intention is to open a broader and more detailed technical discussion. Finally, we conclude with an answer to the question: who has the b...
Will the Lilium Jet work? A detailed analysis by an independent expert.
Просмотров 124 тыс.Год назад
Download PDF versions of the video: drive.google.com/drive/u/1/folders/16IEpl-tQwd244ZVuoIncWn4l8evGRIwH | Timestamps | 0:00 Prologue 3:30 Chapter 1: Fundamentals 42:28 Chapter 2: Aerokurier vs Lilium 1:18:59 Chapter 3: Evolution of Lilium 1:41:51 Conclusion | About me | For an aircraft engineer like myself, the advent of the eVTOL industry is exciting. The industry's current state is that many...
What's the right number for eVTOLs?
Просмотров 5 тыс.Год назад
Aeroplane and rotorcraft configurations have not changed for decades. In contrast, there is an abundance of different eVTOL configurations. A key differentiator is the number of propulsors and how many should be vectored. This video offers a detailed engineering analysis and delves into the tradeoffs involved in the question: how many propulsors should an eVTOL have? Case studies include Joby A...
EVTOLs with these rotors have a potential problem.
Просмотров 14 тыс.2 года назад
The eVTOL concept with wings and fixed rotors dedicated to lift has become popular recently. This video describes the engineering challenge in this kind of design when viewed from a propulsion system perspective. For the numerical analysis, a simplified comparison is made to Joby Aviation’s concept. Chapters: 00:00 - Intro 00:47 - What is the Transition Phase? 06:44 - The dilemma of being a rot...
Das taiwanesische Unternehmen ProLogium hat sich auf die Entwicklung von Feststoff-Batterien mit keramischem Elektrolyten spezialisiert und in Las Vegas nun die vierte Generation seiner „lithium-ceramic battery“, kurz LCB, vorgestellt. Sie kommt laut ProLogium auf eine gravimetrische Energiedichte von 380 Wh/kg und auf eine volumetrische Energiedichte von 860 bis 900 Wh/l. Bei der dritten Generation waren es noch 359 Wh/kg und 811 Wh/l. Bereits vor einigen Monaten präsentierte ProLogium schon eine verbesserte Silizium-Verbundanode für seine LCB.
Well, it's probably not a goodbye, but a see you later.
The TÜV Rheinland report confirms that ProLogium’s next-generation lithium ceramic battery delivers an industry-leading energy density of 811.6 Wh/L (volumetric) and 359.2 Wh/kg (gravimetric).
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.
CSI4Nerds! Thx...
How would an MD520N compare, Joby?
Great video. Learnt a lot by watching it. Thanks for the work
Quite a good video. Clear analysis of both sides of the argument, some additional background information, although I can't necessarily agree with the conclusion by Iceberg Research - R&D tends to be a waste oil furnace for money depending how it is managed it can take a lot of money or even more money to get to something feasible. Adjusting for inflation and comparing to the development of the Osprey or Harrier Jet, the current amount of money utilized is not that surprising.
Can it be summarised as follows: with one propeller the force always goes in the desired direction and with two propellers (90°) the force also briefly goes in the opposite direction?
Excellent piece of work! Thank you! My engineers intuition told me years ago, that this was a highly ambitious project. First and foremost I could not see the necessary progress in energy density happen. Today it had been announced that they have gone bankrupt after state officials dismissed further financal aid. I's a pity! But here we go.
and now they are back again. tada ...
WILL NOT WORK , the battery tech is not there , no range , system is too complicated , and only make a little sense to city to city traffic if any, the helicopter is way reliable and have room to improve if the political can be removed from the helicopter industry. aircraft does not need a heavy and expensive and complicated and unsupported energy source to power them , aircraft is already very efficient
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
fantastic video
Fred... it seems to go unchallenged that an 'air taxi' ,of their kind, has to be completely different and MUCH bigger and heavier than an 'air car' would be whereas the ground taxi (or uber) will just be a regular mass production car simply repurposed as a for hire vehicle. Compare a typical modern four seat lightplane to any of these bloated monstrosities and ask why they are so much more costly and less range speed payload etc but get called 'advanced' as in AAM ... Indeed, a commutting aircraft ie fly to work, cannot be anything like these contraptions.
Strange how a comprehensive comment just gets a ❤ or nothing at all. Whereas some trite line is responded in depth.. This phenomenon of a flood of money and simultaneous emergence of over 1100 designs with absolutely no actual demand or proven feasibility but an obscure report, sans data, by a financier house ( also underwriting the IPO ) leads to the expenditure of thousands of millions of dollars on speculative and inadequate aircraft by previously unexperienced 'entities' . Competent engineers and firms in the aircraft industry had explored this field and found the problems that these upstarts (start ups) are just repeating .. even Bievert should have known better from his mentor, Paul Moller's experience even if transposing the electric power and control from drone models (Canadian origin) might have simplified the task at the cost of almost no useful range or payload, savkng the planet from a non existent threat seems to justify all the cost and annoying side effects (eg noise) that must be paid by the misled public. Until the tunnell vision and blinding by greed runs it's course any questioning of the overall wisdom of evtol will be futile...
Watching the clips retrospectively one has to wonder on what ground the four guys made all those claims and on what basis Lilium was awarded of so many recignitions. In other words, in their paper Lilium did not produce any flight test data to support their by then much downsized performance claims (175km). Hence, the doubt that the aircraft can't even achieve that is legitimate, especially if drag estimation is optimistic (besides of forgetting the canard, the total drag of an aircraft is in general larger than the sum of its components drag). So, coming back to the four guys, at the time when they had no much more than renderings...Why all those ambitious ckaims? Was that incompetence or did they intentionally lie?
The million dollar question. I can only speculate, but they were very obviously naive, inexperienced, and hubristic. This led them to believe in their own fantasy with such unjustified conviction as to capture the belief of others. Thereby demonstrating that a lot of people learned nothing whatsoever from the Theranos saga. More generally, the eVTOL bubble is deflating right now. There is only so long the perpetual promise of “commercial service in 2 years” can remain credible. That phase is over. I think the sector will be dead in a year without a type getting certified. And dead in 2 years unless revenue generating operations are delivered.
Great Video! Any one of those 'Airtaxis' won't be able to provide mass service in Cities like New York - There is NOT enough ATC Traffic Guidance available, nor there are available 'Slots' at JFK or LGA, EWR etc. Since they are carrying Passengers you need advanced Tracking, Collision avoidance, Guidance, Weather etc - otherwise you endanger everyone.
I am pretty sure they thought of these things or what would be the point?
@@annettehurd9391 Selling your Concept and Prototype ... Especially in NYC you can't operate hundreds or thousands of those using 'See and Avoid' Rules, considering there are 1700 ft tall Buildings, Fog, Rain, Snow, Wind. Those are 2 to 6 (or 19 later) Seaters ONLY. Not 'Mass transportation' or doing anything Green, Sustainable etc. ATC is overworked and underfunded right now. Look at the proposed Flight Path 'diagonal' over Manhattan ... smh
Don't use a Manhattan thumbnail if you don't want comments attached to it.
Let's build capricious and expensive ways to get from A to B. Instead of two rails that can serve millions of people. New York could use a Manhattan to JFK line.
You forgot a key parameter. Vehicle mass. What joby and archer both did almost identically wrong. An autonomous single seater has much greater potential for low sound footprint and physical footprint to set down in urban areas. A particular win would be if such a vehicle will be allowed in the luxurious hills of los angeles so they can have little landing platform and go from their view to LAX or Van Nuys in mere seconds and board their plane. Or for that matter set down in beverly hills for a bit of shopping or brunch :) If an EVTOL can pick you up at a bar at 3am in the morning and take you home that has incomparably greater potential than the very conventional helicopter thinking that joby and archer are wasting billions on. And I have pointed this out for many years but nobody listens. They all know best and then they go bankrupt after wasting a billion effing dollars. If the world listened to me we would have star trek by now and that's not even an exaggeration.
Sprinford, i worked on the prototype NOTAR when it was being developed in Australia by HawkerDeHavilland and felt it was not such a good idea then (1990s) with the main idea being to remove the danger of tail rotor strike or even stall , not so much noise.
Excellent dissertation that does more to clarify the noise issue and measurement/metrics than any other i have seen. I will append my comments on it but firstly reiterate my basic thesis that they are all solving the wrong problem by focussing on vertical take off and landing per se and not seeking a better solution to the specific task of moving people, by air, in a built up environment ( with constraints of noise and cost,safety, air quality, etc and the sub issues of manufacturability and operation at a sufficient scale to really improve the traffic congestion issue that they espouse as their aim. The correct starting point ought to be the well established curves relating road traffic density versus both flow rate ( speed) and flow volume ( vehicle numbers per minute ) The total number of vehicles per minute is the crucial figure if any amelioration of congestion or even gridlock is to be acheived and occurs at a lower speed than the unimpeded travel speed limit so gives the most benefit to the most people overall. The most basic arithmetic shows that the existing flow volume is orders of magnitude greater than any conceivable evtol system could even make a measurable impact on ( around 5% of the "saturated' , but not jammed, flow rate needs to be removed to get back to free flowing conditions such is the non linearity of the flow versus density curve. The higher productivity of airborne vehicles makes each one equivalent to perhaps ten or more road vehicles if the appropriate infrastructure for evtol that will not be possible or tolerable. The only feasible way to have a viable air transit system for urban and suburban use is via ATOL or assisted take off and landing which fortunately, also solves the problem of noise ( being no noisier than the flying of a kite or winch launch of a sailplane and with no more need for brute power or disturbance than either (no hurricane level downwash etc) So the noise issue is best solved at it's root rather than trying to tame something that NEEDS hundreds or even thousands of installed horsepower just to get into the air at all. That is the most fundamental comment that bears on the noise issue. If a baby cannot sleep through such an aircraft taking off ot landing in the street outside then it is too loud ( there ARE no "100 metre" - radius - open spaces either in urban or suburban precincts to even make a noise level at that distance relevant , 20 metres might be suitable. (Or the noise of a modern ICE car say already acceptable ) Before i get onto a comment/ critique of your video i would point out that prior to the evtol craze there were two notable projects aimed at very large noise reduction in relatively small aircraft , by NACA in the lare 40s ysing a modifidd Stinson and in the 70s for the Vietnam war using modified SGS 2 32 sailplanes and ICE ('rattley' air cooled Lycomings even) that produced the quietest well tested aircraft yet. They were undetectable when flown on still nights only a few hundred feet above enemy troops and a quiet jungle background. Just to make the point again that by designing to NEED only low power the job is automatically easier than if you must go up ,and down at 90 degrees using sheer brute force - this approach can never be quiet. Critique; the examination of sound quality and quantity is excellent and gives a far clearer picture than the exagerrated and misleading misuse of figures by Joby and Archer et al - one other aspect is that sound from ABOVE is more perceived as 'bad' than from elsewhere because it is more likely to be a threat as felt by our more primitive brain areas (being pounced on ...) directionality matters. The turbulence into propellers issue is crucial to any downstream and in the case of Joby the rear props are working in the maelstrom coming from the front inners ( see their flow animations) Evtols have to somehow dissipate maybe 200 mph before landing at zero forward speed and ,like helicopters, will likely have to "flare" nose high to use lift braking which increase noise drastically, i used to live right next to a sports oval that doubled as as a helicopter medevac pad and my whole house shook when they arrived and did a landing over the roof in autogyro mode ( no hover ) to save time. Gentle hovering to and from ground is just too slow for any efficient turnaround. Blade twist is bad for hover efficiency bad essential for forward flight so both are compromised needing more power , downwash impinging on the wings and tail adds extra download and more power ( equalling the payload itself in the V22) Blowing a vee tail is a bad idea since a half a vee tail is no tail at all - several v tail glider accidents from control dis connects have shown this... on the other hand unblown tailsurfaces with the rest blown is also bad (electroair, Archer etc) control in gusty winds is not going to be good, carrying excess power and keeping some pitch in reserve for control might also add to noise. All in all vtol is a bad idea when what was wanted was to avoid needing a runway, or an airport, or any ground roll - not hovering for any useful end like a helicopter rescue etc ( for which battery evtols are no good) Hence the whole noise issue is a side effect of a basic conceptual flaw, it also requires six separate vehicles and six operators for every return trip (a commute say) and the logistics of organi,zing it all, car (taxi parking) and changeover spaces etc waiting rooms and so on as shown in the uber elevate videos. So noise might be a make or break issue but it is far from the only problem the evtol has. It could all end in tears 😢
To add to my comments a bit, the ultra quiet Vietnam stealth aircraft were the Lockheed YO3a and the earlier QTs , basically powered sailplanes using minimum power to sustain flight by low span loading primarily, evtols and even estol are the worst possible application of battery power in terms of noise also. The 'tempo ' of operations is another noise annoyance factor as is the duration of the noise, airships operating from Melbourne got many noise complaints because of the length of time their lasted, helicopters ( mostly police) loitering circling also gets on the nerves. The Berlin airlift was a case in which non stop operations gave a taste of the projected Uber air intensity of turnarounds needed to get any profitability and the side effect on those near the flight paths. Having lived, in total, over seven years ON airports I am aware of the issue 😊 - there were videos by vtol research showing ca. 100 dBA for the Archer and earlier independent video/ audio from Marina airport of the Joby s4 which were anything but quiet, just hovering ( no climb power,) IN ground effect is the least bad case for noise, the "rear up' speed dissipating type landing is very much louder than hover transition and involves much blade stalling. Just listen to someone exercising a variable pitch propeller on run up to see the effect. Curfew will be imposed for any residential areas for certain, only ATOL can be installed or used in suburban locations ( using the free air space over the road and giving thereby immediate access to the roadway for departure and arrival as a road(able) vehicle, Note Bievert stating that his aim is to take people as close as possible to and from their destination and home - evtol is a failure at this and not least because of the turmoil and noise created plus the monumental overbearing structures required as vertiports/ pads unsuited to suburbia ( a see through cable array suffices for ATOL. The degree of unneccesary complication involved in evtol and extreme measures needed to shave weight etc eg by threeD printing parts, carbon autoclaving etc ( so admired strangely by production guru Sandy Munro) reminds me of the scene from raiders of the lost ark (?) where the king fu swordsman does his expert sword waving routine to which Indiana Jones just looks perplexed as he pulls out his gun, blows the guy away, and carries on... some expertise is just irrelevant to getting a job done...
Impressive analysis. Could you also include the effect of the turbines or engines as well. I think it is not only the aerodynamic noises buy the engines that contribute to the total.
Thanks, Ernest! I briefly mentioned combustion engines in this video but had to scope it out in order to keep this video within reasonable lengths. I think engines play a greater role in noise when you are sitting inside the plane. At further distances, propeller noise should be the dominant source still. But, like you say, engines play a role to the overall noise profile. I do not plan to talk about aircraft noise in the foreseeable future, so I hope someone else can pick up this subject. Cheers!
Interesting video, thanks. Just want to point out that Helicopter buyers have already rejected quieter aircraft. The MD NOTAR aircraft are much quieter but are a commercial failure with very few sales. Looks like they are no longer available as a new purchase.
NOTAR has some performance limitations that tail rotor helicopters don't have (less authority in certain conditions). I don't think they failed BECAUSE they were quieter.
very comprehensive
Toroidal propellers?
If they had benefits they would be used, or even just considered. But many years later, I' surprised someone even remembers that scam.
@@g.zoltanwhy don't they have less induced drag?
@@jo21e6 That is correct, but theyalso gain a lot more in parasitic drag. The surface area and cross section gets so much larger!
Thanks John, and i agree there is great potential in eVTOL for noise reduction. You pointed out the difference in the ground cover between the EVTOL Research videos, but I thought you might have mentioned the Joby video of the hovering S4 measured from across a field of long grass - some of the best noise attenuation available. That was a dodgy marketing video! Also, the camera lens could well have foreshortened the distance from JoeBen to the aircraft, the aircraft be downwind of the measurement point and/or be at minimum gross weight. If they are so good, why spin 10X into a false claim of 100X or 1000X, improvement?
Thank you Murray, I am glad to hear from you again. I would add that Joby's aircraft measured 55dB at 100m in that particular video (see 0:56). But later communications by Joby state 65dB at 100m (see 57:44 or www.congress.gov/117/meeting/house/114372/witnesses/HHRG-117-PW05-Wstate-BevirtJ-20220317.pdf). Their current website states that their aircraft measures below 65dB at 100m (see www.jobyaviation.com/news/joby-revolutionary-low-noise-footprint-nasa-testing/). Cheers!
How would varied pitch affect the sound? I notice when they take off they are drastically pitched and not when they are displayed. They didn't let us hear it when they flew a pilot for a few seconds.
Id assume no payload and smaller battery but im the most skeptical person on the internet.
Love your work
You released it early! An early Christmas present to us. Thanks.
Thanks for coming by!
The detectability of sound is not linear, and saying "1000 times quieter" is disingenuous at best, untruthful at worst. Sound must be 1/10 the pressure (or -10dBA) lower to be perceived at half the loudness (an oversimplification). So 1/1000 (or -30 dBA) the pressure is (1/2)^3, or 1/8th the loudness.
I would add a small correction: sounds must be 1/10 of the original *sound intensity* (or -10dBA) to be perceived at half the original loudness. In terms of sound pressure, this would would be around 1/3 of the original sound pressure. Cheers!
I need more midrange acoustic frequencies. Your attempt to make your voice sound deeper diminishes intelligibility.
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1:05 I want to discuss about this. Having studied aero engineering, I tried to create simple conceptual designs for EVTOL craft, just for amusement, but using very basic "napkin" calculations, I struggled to make aircraft concepts that would outperform a hypothetical heavyweight electrified helicopter. I wonder if my simple calculations are based on incorrect assumptions, or they show a valid criticism of the EVTOL industry. I'm mostly suspicious about my assumptions on distributed propulsion. It is hailed as a game changer, yet my basic calculations didn't yield meaningful gains over an equivalent setup of a larger laminar wing with a large single pusher prop. I'll have to review more literature on this topic, but until then I wonder if you have a take on this: do you think my results are plausible, or did I "fail the exam"?
Jackpot
I think your results are plausible, assuming your performance criteria are payload, range, and endurance. In my view, distributed electric propulsion has overpromised and underdelivered on many aspects of aircraft design. Aircraft performance is one aspect where DEP promised improvements but has failed to deliver so far (on commercial planes). However, one aspect that DEP is legitimately useful for is aircraft control. I think drones or UAV’s demonstrate that DEP can be a very cost-effective solution for achieving VTOL capability and aircraft control during hover flight. This is my view on this question; I am curious to learn what other viewers think.
Is it about performance or noise? I’m confused about whether I’m missing something important about the topic.
@@ZnOxide Ok, let me try to remember. *My outcome parameter or optimization parameter is:* flight range, that's all. *My input parameter is:* battery weight. Outcome parameters are optimized for 3 battery weight inputs. *My boundary conditions were:* A fixed light payload, mandatory hover descent for X km's to simulate a sane takeoff/landing, Y minutes of reserve for hover flight, I think it was around 15minutes, well bellow the current helicopter requirement of 45minutes, a really optimistic structural efficiency model that assumes modern aircraft structures, Z meters of max wingspan to allow landing on existing helipads, simple conceptual deisign charts for stats (such as efficiency) of electric motors, batteries, propellers, airfoils, and basic fuselage geometries. *My variable parameters* are chosen freely to yield the best outcome parameter, these were: flight profile (ascent/descent), flight speed, wing geometry, and others.
You forgot that toy drones are cool and that every investor would love to zoom around in a bigger version of that.
It seems to escape most discussions that Lilium cited all these papers, but they could just have shown their own test data. Why cite obscure papers when you can just show that you can hover X kg with power Y?
I think this is one of the most german videos I've ever seen
When it comes to jet efficiency tenet No1 reads: MAKE IT BIG. The bigger the better. Just look at USAF Osprey. The rotors are not so big because they look better this way. No, because they munch up less energy during ascent and descent. Lilium´s bird looks certainly elegant with 30 tiny toylike impellers. But all they do is multiply the waste of energy. For Lilium function follows form. I suggest they donate their prototypes to MoMa and enjoy the millions of dollars they earned for creating a nice sculpture.
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?
Today, there are off the shelf motors that have effeincies of up to 97%.
Absolutely one of the best debunking videos I know!