Interesting video as always. The efficiency multiplier for distributed propulsion is amazing! I can imagine small regional airports coming back to life with an increase in electric STOL aircraft services.
What efficiency multiplier?? Youre literally only multiplying wingtip vortices drag by an order of magnitude rather than having one big very efficient propeller. Not only that, but the aerodynamic drag is increased dramatically. Not good for electric aircraft with already severely limited on board consumable energy. I have no idea why this concept of "distributed thrust" designs with like 500 motors keeps on resurfacing. It's cool looking vaporware, but that's all it is. If this weren't the case, I can assure you that airlines would've already figured out a way to achieve this with conventional jets. The ONLY way I can see this being feasible is with maybe 4-6 motors located inside the wings blowing through a diffuser that runs along the length of the wing. That would work far better from an efficiency and aerodynamics perspective, but still would be woefully less efficient than a 1-2 propeller design with larger motors and larger props. It's pretty much commons sense.
@@scenicdepictionsofchicagolife Lilium vs. Archer vs. Beta Technologies eVTOL designs you are talking about? ua-cam.com/video/x8OTNPugl24/v-deo.html ua-cam.com/video/-nZ1MMzKfmM/v-deo.html
@@scenicdepictionsofchicagolife They probably compare to machines having the same STOL capabilities = huge wings. Small wings are the biggest obvious win. The second are tip-propellers. Yes, many small engines are lighter than one big one, it is a basic scaling law. Scientists love to cheat by creating meaningless synthetic benchmarks and try to impress audience that they have different practical meaning.
there's a lot of focus in this space on making Uber's business model work but I can see this type of craft really revolutionizing general aviation and hopefully improving the safety record.
would bet that any air taxi service will end up being AI controlled, which really that's an easier problem domain than self- driving cars - that would mean only cargo weight will be passengeries
@@TheSulross I don't know how that would work with current ATC. Probably need the FAA to finally implement their Nextgen program because relying on speech to text for all of this would be a nightmare. I know reliable robotics just has a drone pilot to handle coms.
Something I feel worth discussing: One of the big issues for current electric aircraft is the need for reserve endurance - if a problem develops at your destination airfield, you need to be able to fly to another one. These reserves are relaxed for helicopters as in an emergency, they are more likely to be able to land safely without an airfield. This means that aside from other advantages, in comparison with a conventional aircraft a VTOL vehicle should be able to make better use of its ultimate range. Thank you for a very interesting video. I learned a lot from it.
@@pogo1140 Electric systems can have stupendous power to weight ratios compared to turbines or piston engines. In many ways it's a lot easier to build an electric VTOL aircraft than a classical rotorcraft. Energy density - range - is where the problems lie.
@@pogo1140 Compare Burt Rutan's Quickie and the Blackfly VTOL aircraft. The Quickie has an 18hp piston engine that weighs 36kg. The Blackfly has 16kg of electric motors that provide up to 336 horsepower, and the weight of the additional motors you need above those that are required for horizontal flight, is at least partially offset by the lack of landing gear. It's all great until you consider the low capacity of the battery - but this is a problem whether your vehicle is VTOL or takes off conventionally from a runway. Now, imagine that you wanted to make the Quickie capable of vertical take-off and landing, you would need to install a bigger internal combustion engine weighing hundreds of kilos.
Short-range use is exciting! You can get 4 miles/kwh with USTOL (Ultra-short Take Off and Landing) if you can live with a 100 mile range, which is well within commute/recreational use! Even those high-maintenance, high fuel use helicopters never travel more than about 50 miles from base. I could see every TV station (if they still exist) ordering one to replace their "traffic copters", and Med-Evac very quickly shifting to multi-motor EVTOL (special case where VTOL is required).
@@pogo1140 I think the OP was saying that most helicopters have a limited radius of operation - around 50 miles, not that they are limited to that distance.
@@pogo1140 "high fuel use helicopters" is what he said. Many helicopters have ranges like 200 miles or more but that's only in one direction. The helicopters he's talking about have to come back to base too, while using some amount of fuel at the mission site.
I love this channel so much, keep going! I believe nothing can accelerate the transition to sustainable aviation as much as public interest and support!
Very good video as always! I wanted to share some constructive feedback (hopefully!) though that your focus was more towards the takeoff performance than the range aspect in my opinion. (Ex: @6:15) Takeoff is such a small phase of flight that its power requirements are sometimes insignificant to the range. It's clear that there are benefits to distributed propulsion. Since lift is proportional to the speed square, the relative velocity increase provided by the small propeller can give large gains in lift. Additionally, the Reynolds number is increased, and typically the CL is higher with higher Re. But the research you link also shows some compromises that have to be made for each application. Despite having a higher thrust to weight ratio with the smaller motors, the aircraft was 11% heavier than the base aircraft. I cannot see the study, but did the aircraft use less power to cruise even when it weighed 11% more? Because that's what really would affect the range.
NASA in their Maxwell Aircraft were able to make the wing lighter and higher aspect ratio. The weight they saved from wing made the aircraft lighter overall even with the additional motors. Less wing area also meant less drag. So both high aspect ratio of wing and less drag help the aircraft in cruise. Thanks for you insightful comment
Exciting to see how we are gaining new insights all the time. This really helps me feel more positive about the future that awaits my children. As always, I particularly love your delivery - concepts are articulated with incredible clarity and always with context. You have an exceedingly rare ability to communicate at this level and I often refer to your videos when I am preparing presentations myself (I have been in management consulting around the globe for over 20 years). Regards and thanks from Sydney - Dave
Amazing. We should really go for it. Less pollution, less roads, more flexibility, less traffic jam, more live quality, more terrain for agriculture, shorter commute between X and Y, lots of advantages. Smaller plains, less components, saver, cheaper, less CO2 footprint, more aesthetic, less dependence from large companies with goal to exploit you. Go for it!
Some info presented here are not quite true. Distributed propulsion usually performs worse than a single rotor if you consider propulsion alone. This is due to degradation of the flow characteristics on the blade due to smaller Reynolds numbers. I have discussed this with Dr. Nick Borer from the NASA X-57 DEP CTOL aircraft team, he specifically mentioned the smaller propellers used for distributed propulsion were performing badly, about 50% efficient, and that's why at higher speed they are stopped and folded. What the distributed propulsion actually does - it increases artificially the wing lift coefficient, the wing can be much thinner, having a lot less surface area, without a reduction in stall speed, but having much better high speed performance. Having a smaller chord wing, same wingspan, increases the maximum L/D and moves this maximum at a higher speed on the L/D characteristics. The smaller wing actually is the reason the range increases, not the multitude of propellers. The distributed propulsion is to allow the wing to perform at slow speed and have a relatively slow stall speed, similar to the original larger wing.
I wonder if this can be used not to fly slow, but to fly high? Basically, to achieve benefits from both low air density and relatively low speed (of the fuselage) to suffer from drag even less.
thanks for showing DEP and boundary layer ingestion. i think that with distributed propulsion is more appropriate to use closed wings as joined wings or box wings because it gives more structural stability and reduces flutter, a trade-off of distributed propulsion.
Retrofit electric motors to an Antonov 2 biplane, which has incredible STOL capabilities. U Plane with 9 engines. Run-up of 6 seconds / 60 meters. MAX 2021 / TVS-2M... ua-cam.com/video/sI32NIvjvic/v-deo.html via @UA-cam
The next level is to replace the electric propellers with electric compressors, each directly connected to an oblong shaped bladeless fan built into the wing's leading edge so as to deliver the maximum laminar flow distributed across an optimized wing surface. So you are multiplying the lift and and mechanical airflow both. This should result in doubling the range again over the propeller design, allowing the electric system to easily beat the conventional one in subsonic flight. One could also incorporate a hybrid power source as well, making electricity onboard in an optimized RPM range for efficiency. The resulting efficiency in fuel consumption would approach an order of magnitude, the electrical approach allowing the optimal mechanical power distribution for a given form.
@@ElectricAviation Thank you. I am seeing some companies like Easyjet bringing an electric airilner to market and wonder how they will handle propulsion.
I can’t wait for someone to build a bush plane redesigned to fit multiple motors for super short take off and landing. Those bush plane pilots would know how to make the best out of it!
@@chrisglencross3867 Excellent remark. Yes and no. The flaps would extend the whole width of the wing, but the main wing would contain them as an envelope. So they wouldn't exactly be flaps but a double corded wing... Hope I'm a helpful troll 😅
Have you seen Mike Pateys transformer wing? I dont know how this would integrate with distributed propulsion, but it does nearly exactly what you are suggesting... Edit: I see from other comments you are aware of it:)
Two things come to mind 1/ that trailing edge or pusher propellers would endear a straighter, more predictable flow over the wing, especially concerning the leading edge; further optimising Clmax 2/ and Im unsure the advantage of short take off, as the present experience deals with 'average' take off durations quite well, ... and hull insurance on STOL aircraft has proven in the main to be commercially prohibitive ok make that 3 things ....
Some very interesting information. Now the question is will an electric version of a turbofan jet engine be even more efficient? The electric motor would replace the axial flow jet engine. Keep up the good work. I love to see people thinking outside the box.
intelligent propulsion company, owned by rogers msuya, has invented something new that can generate electricity onboard... eliminating all hurdles facing the Electric Mobility today!
Great informative video on the advantages of distributive propulsion and eSTOL being more energy efficient than eVTOL. Will you investigate the PLIMP hybrid airship design and give the pros and cons of the design?
Can distributed propulsion setup with small open propellers also achieve the high top speeds of a large EDF in forward flight? Hey how do I get in touch with you?
VTOL would be great mainly for short hauls in the city and no transformer shape change necessary with the short distances. I agree STOL is way better especially without any transformer shape change which makes it easier to make, lighter and simpler. And you maybe can design STOL to near VTOL performance. e.g. A semi Black Fly idea with wheels and a slow landing speed that can easily stop short.
Fascinating drag reduction of the many movable,you have made a comprehensive history of aviation,you are a scholler of flight,good visuals 2 communicating the possibilities of a pure electric development of flight with little propeller flight ,straight up into the cruise multiple people/cargo load bearing capacity at highest speed ( :maybe capacitors could give batteries a boost on take off,or we could make big half mega bridge's into the ocean ,and shoot them of from ground batteries into full cruising speed,you could have bicycle s and car's drive into wings and battery,and are shot off the half bridges without there tyres/axel and chassis,batteries would be interchangeable with rentable wings
Very good coverage of this. VTOLs are likely destined to serve as urban robo-taxies rather than go to traveling vehicles, imho. Could you cover this aspect please?
This makes total sense, and clarifies the thought I had for a very long time! Always felt VTOLs are overrated. STOL removes a lot of complexity required for the VTOL functionality, like tilt rotors and bigger propellors etc. Most people anyway won't be able to afford to fly in electric helicopters even if someone launches it. Making it simple makes it cheaper. Very good content and analysis, keep up the good content!
But is VTOL with tilt-wing that much more complex? It seems to me tilt-wing could have almost same efficiency as STOL. I imagine a hypothetical future where A LOT of road infrastructure could be replaced using VTOLs.
@@gianpietro6915 Agree. STOL can't do the air taxi role. I was saying mostly in the context of longer, intercity kind of travels, and a 'nearer' future use case
@@dejayrezme8617 I felt it adds quite a bit of complexity for supporting VTOL and hovering capabilities, and landing on a helipad or in a very heavily crowded areas etc. (Just my assumption - not much educated on this though) I too wish if that hypothetical future of flying taxis could happen soon. But I'm not sure a whole army of flying taxis always roaming in the city sky is a great future to look forward to. Just imagine this - a 4 lane motorway could carry 1000s of electric cars and no-one will even notice, but if 1000s of flying taxis fill up the sky, it's an eye-sore and horrible experience to be underneath. Beautiful CG renderings of one flying taxi in a city (showcased by every EVTOL startup homepage) is beautiful, but at any given time, in a big city there are thousands of taxis and Ubers running in close proximities. And unless something unheard of is invented, areal vehicles will have the sound of wind, and will have to keep some distances too... So chances are, it'll be limited to only the top rich few for practical use(do you think/want millions of people to take it?) Maybe decades later, when the entire sky highway infrastructure is precisely managed and controlled by AI and AI alone (must be un-hackable too), and aviation without much influence of weather is achieved, I'm skeptical. (Omg it was quite long!)
@@JoeMathew Think about it. The axis has to be strong enough to support the weight of the aircraft at 3-5g meaning support the weight of the aircraft and payload x 5, and all of that weight increase can come in .5 seconds. Then the two rotors have to spin at exactly the same speed with exactly the same blade pitch. If one motor fails, the plane crashes. If you use more than 2 rotors, that means more weight, more power needed, more batteries more weight which means more powerful motors which draw more electricity which means more batteries which means more weight and so on.
Thank you for your excellent work 👍👏👏👏... you have basically insinuated that we are about to see micro airports in the middle of bedroom communities around the country... quite and clean aircraft will change air travel completely
Maybe with a conventional combustion engine which increases in efficiency with size. But as stated in the video, smaller electric motors are more efficient than larger electric motors.
Distributed propulsion simulate what a bird wings would do if it was flapping its wings to get lift. The airflow is evenly distributed over the whole wing and not just a section of the wing. They should design bigger aircraft with this in mind.
I did watch your video on fuel cell flight, and still don't perceive you gave a fully realized evaluation on that, but this was informative (for me) about take offs (?)... Did you say there's a larger drag coefficient at certain heights, weights & speeds?Also still also a matter of public access, when it comes to vtol flights without runways, & nothing is wrong with romance... It's romance which is correct.
I see a lot of companies pursuing VTOL and think of the wasted energy. VTOL is unnecessary in most instances and only serves to increase the cost of flying. I am excited for full electric aircraft, however I am impatient. Can you do a video analysis of Pipistrel's Panthera Hybrid system?
This guy: Talks in depth about the science behind and efficiency of battery powered aircraft Also this guy: Refuses to replace the dying battery in his smoke detector
This is a remarkable video. There is clearly a very good business case for the light private pilot aircraft segment. Why is this not being pursued? Also, can you state what each of the prototype EV aircraft you were showing in this video are? Probably with a link. What was that dual wing, multi-prop one with the tricycle landing gear? And the DHL one? Would like to know who's behind these designs. I get the feeling that many developers are approaching the design aspect wrong, based on what you're saying. Someone should start by just designing the optimal airframe and propellor setup, and work back to a working aircraft from there. And all propellers should have the capacity to stop and fold along the motor in order to allow more efficient travel at cruise speeds and altitude on just one or two motors.
Do you think Joby and Vertical will be able to take off and land like a conventional estall aircraft where it’s appropriate to do so and save some power for longer missions
Check out the XTI Aircraft Trifan design....gas turbine driving a generator that powers motors driving ducted fans which rotate for either vertical or horizontal thrust. XTI plans to replace the gas turbine with batteries when battery energy density improves. Full disclosure: I own shares in XTI aircraft.
I know Trifan and I like the aircraft very much. The reason it caught my eye was because I did an independent study for VTOL and came up with three props, more or less the same dimensions as E fan
So, using 100hp motor with 8' dia. prop, would burn more fuel than four 25hp motors, each with a 4 foot diameter propeller? Would the propeller design and rpm's make a difference?
Seems like it would be worth while to create launch assist drones that attach temporarily to the craft, and they would be designed to provide one minute of thrust before they disconnected and fly back to be recharged for the next launch. Anyone doing that sort of design?
Yeah, but in an STOL you are still taking off and landing on a runway, which is existing infra usually built far outside of the city. And even if you start building custom runways of let's say only 50m you still need empty space for approach, and for city travel that's still a lot of prime real estate space dedicated for landing infrastructure. The reason people are excited about eVTOLs is specifically that it enables point to point because the landing infrastructure is so much less involved. Nothing to do with flying cars.
ICEs advantage is in the fuel. the rest is poor efficiency. Because fuel is ~50 times more energy dense it just allow ICE engines to linger and show they wastefulness :)
Good thought. I at first thought kinda the same thing, but ICE has problems (beside the lack of biofuels and noise). If individual engines, they are heavy, complicated, and inefficient. If one engine geared to multiple fans, it could work but would add complexity, maintenance cost, and a failure could be deadly. Perhaps best would be to use an H2 or Methanol fuel cell if you need maximum range, but for everything else I would think an electric battery is better. (Also, if you use a fuel cell you can always upgrade to batteries when they become higher power density than fuel cells).
For small planes, people have been moving away from multiple engines for years because you don't really see the payback in performance. for the weight and complexity. You'd be better off adding a diesel or turbine range extender if you need more than what a battery can provide.
Solar powered electric airships (rigid Blimps) could take over a huge portion of freight flights point to point with almost no infrastructure. I’m amazed there is so little interest. Point to point at 120 mph with no wear and tear or clogging of roads would be extremely helpful. Quiet and no pollution also good. Modern technology would mitigate hydrogens flammability as it has lithium.
Dear Electric Aviation, we are big fans and followers of your work, we are currently working on a project where we feel that your expertise could be of help, do you ever do any consultation work? please contact us as we would very much like to speak with you.
I have a full time job so I cannot do consultation work as such, but it would be interesting to exchange ideas. You can reach me at Haroon_Junaidi@yahoo.com
A propeller is in general good in some regime and bad in rest of regimes. Mostly like a wing. Like the wing is very sensitive at what you ask it to do and adding complications on it guarantees to make it worse. Just like the wing. That's why props on wings are in general bad. But some dream... Like the guy with this channel.
some helicopter propulsion systems have envisaged such a proposal I think one of the entrants for the Sikorsky prize, a human powered helicopter to fly in a figure 8 pattern, used a pedal driven generator to a tip mounted propeller.
@@Soothsayer210 I mostly meant it as a joke... But now that you ask, I'm thinking a barrel shape, with propeller blades spaced evenly along the outer edge, actuated to vary their pitch, with a ring of propellers at the top also actuated. It would take off vertically pointed straight up, using the many small propellers for direct lift. It would then start spinning the entire thing so the outer propellers would produce lift as well. At high horizontal speeds, the small propellers no longer produce thrust in the direction of travel, they are used exclusively to generate spin for the larger propellers. Inspired by the flying cylinder frisbee sort of toy. You throw it like a football and it gets lift from spin. It's probably a terrible idea, but with enough thrust SpaceX got a water tower to fly.
Its great for acceleration and take-off and landing. Once cruise speed is achieved, you can use either all propellers at low speed , but even better is to use the large props if any for more energy efficient cruise.
blowing the wing with the motors allows them to run a much thinner wing than would otherwise work at low speed. That wing is much more efficient when they're at cruise and at that point there's enough flow and lift to support the aircraft. The big ones on the tips are also counteracting vortexes that form on the wingtips, so that's also adding some efficiency. Hence why the main props are much more outboard than they normally would be.
@@AntonEMaes Thanks. Most of the aircraft in the video are not examples of distributed propulsion enabling thin cruise-efficient wings (and therefore long range). Love this channel though.
Very interesting. The lack of energy density in batteries is certainly forcing people to squeeze the sponge hard for every last drop of advantage. I wonder what would happen if tomorrow we had a game changer where we saw density at a 1000 times what it is now. It would probably put efficiency chasing on a back burner for quite some time so maybe the lack of density we have now drives a science benefit in other areas we would not have otherwise had.
That's certainly physically possible! I think the physical limit would be a fuel cell, because you still need the Hydrogen to hold the electron... essentially a fuel cell.
Please clarify what you mean when you say "5 times more propulsive efficiency" with distributed propulsion @6:58. Propulsive efficiency cannot be greater than one. Do you mean a 5 percent improvement? Thank you.
Lets say the propulsive efficiency of an aircraft with one larger propeller was 0.15, than 5 time propulsive through multiple small props means efficiency of 0.75
@@ElectricAviation That is not a realistic example. Propulsive efficiency is the ratio of the thrust power to the mechanical power delivered to the propeller. Even a single propeller aircraft should have a propulsive efficiency greater than 0.75.
I really do wonder if the best combination would be a ground effect aircraft with hydrogen fuel cell electric propulsion for at least 80% of propulsion needs of 50+ person passenger aircraft... 🤔🤔🤔
God: the only way multi props will work & b efficient is in the FAT thick wing trailing prop design & the air-foil prt shape of the wing is the channels between the props.
Car's flying cattermerangs,gigantic shipping crude oil splerter's with paragliding sails/giant kites pulling them along in part with shipping lanes battery packs ,improving the sea and the cities,and the air
My hope is a combination of small STOL aircraft with AI control system would liberate humans to live in smaller towns. Current flight tech makes travel from smaller towns not economic, with most only achievable with large Govt subsidies. If the cost of the flights is halved, likley even more with the low cost of electricity and much reduced maintenance of elctric motors compared to ICE planes, chosing where you live can be much more about lifestyle.
Do not over amp the motor use the Edison generator for electric power source. An old generator can be converted to Edison power by chiseling off the Tesla magnets and leaving the Edison magnets on the generator armature. A pre 1974 car generator can be used count the armature magnets and divide by six and chisel off one sixth and leave one sixth on and then off and on until you have chiseled off three sixths and left three sixths on alternating on and off. The generators are motors and will spin as you assemble the generator. The generators self spin unlimited generation of electricity. You have replace the commutator brushes. Add inverters and transformers to deliver power plant power or house current. But 12 v power continuous peak power or 110v AC is immediately available for airplanes power for an unlimited time . Redundancy is safer.
if batteries are designed to be easily swapped out then electric vtol air taxies could become a thing - every air pad could have charged batteries waiting to be swapped in
@Electric Aviation If distributed propulsion is more efficient why Airbus and Boeing are increasingly making commercial airplanes engines bigger and bigger ? In the past they had 2 or even 3 engines per wing and now they have just 1 big engine per wing, so if distributed propulsion is more efficient, Why they didn't made the jet's core smaller (in order to increase the bypass ratio) instead of making the fans bigger and leaving just 2 big engines ? And now Why are they making them even bigger instead of putting more engines ?
It is because they are only concerned with jet engine efficiency. With higher bypass ratio, they can get higher efficiency of the jet engine. Over here we are discussing propulsive efficiency, in which the rotor downwash is directly blown over the wing. In commercial airlines, the engines are hanging below the wings, which increases the wetted area and hence drag. However, the make up for it with improved jet efficiency.
Hello, At 3:22 you say that smaller motors have high trust to weight ratio, but when i look at another video you put online: ua-cam.com/video/O0vQbSfuufE/v-deo.html And you go to the stats at 04:24 I see that the trust to weight ratio is lower. Can you or maybe someone else explain this to me? Best regards, Jan
I listened to this video hoping for some kind of explanation for the claim but heard nothing. Therefor, I believe that in the absence of rational scientific cause, the claim is bogus. The video did mention what I consider critically important, which is the calculated thrust to weight ratio of the engine and aircraft. But, I heard nothing about why distributed power should be more efficient or be reason for a superior thrust to weight ratio. I will say that AFAIK, fewer and larger props and engines do run into certain limitations... The propeller tips must not travel faster than the speed of sound. The propeller must be optimized for a particular speed. An optimized propeller will account for the different radial velocities closer to the hub and along the propeller to the tip. Of course, an optimized propeller will have an airfoil shape. There can be additional features that can help propeller efficiency like ducting. Maybe the idea is that with smaller propellers, the extreme difference of the propeller's efficiency from hub to tip is possibly less, but that might only mean a less optimized propeller shape might be required. It might mean that with smaller propellers, the propellers can spin faster, but that's hardly related to propeller efficiency which also depends on airfoil, angle of attack, materials and more. So, based only on what is in the video, I don't think that its claim is accurate. Need proof, or at least a sensible argument.
The more motors and propellors you add the more weight and drag you add. So adding a bunch of motors defeats all objectives. Thus guy does not understand why early aircraft had many engines. It does nothing positive once you meet redundancy requirements.
I've never understood this concept.. why multiply the drag penalty of one small propeller 10x times when it is well known bigger propellers are more efficient... efficiency is a much bigger deal with limited on board energy. This does NOT have better propulsive efficiency. Whoever told you that is either full of shit or has no idea what they're talking about. If this wasn't the case, then turbofan engines wouldn't exist and the fan part of the turbofans wouldn't keep on getting bigger and bigger.
That is because they are optimizing jet efficiency ahead of propulsive efficiency. Larger jet engines are more thermodynamically efficient. Larger bypass ratios give better fuel economy. This is different
@@ElectricAviation not at all different. Thermal efficiency of gas turbines increases maybe in the single digits of percent. The larger bypass ratio is one thing, but that if just for the turbojet. Turbofans have large bypass but also are essentially just extremely large turboprops. So same principle. I'm not sure how that's confusing. Thermodynamics works just the same for an electric motor as it is for a Brayton cycle gas turbine - and theyre both driving a propeller / impeller. There is a reason small turboprops burn almost as much as larger ones. Distributed trust is a mockery of physics and this is ty end of discussion. These stupid designs will never fly or be commercially viable. Mic drop.
Interesting video as always. The efficiency multiplier for distributed propulsion is amazing! I can imagine small regional airports coming back to life with an increase in electric STOL aircraft services.
Great suggestion!
What efficiency multiplier?? Youre literally only multiplying wingtip vortices drag by an order of magnitude rather than having one big very efficient propeller. Not only that, but the aerodynamic drag is increased dramatically. Not good for electric aircraft with already severely limited on board consumable energy.
I have no idea why this concept of "distributed thrust" designs with like 500 motors keeps on resurfacing. It's cool looking vaporware, but that's all it is. If this weren't the case, I can assure you that airlines would've already figured out a way to achieve this with conventional jets.
The ONLY way I can see this being feasible is with maybe 4-6 motors located inside the wings blowing through a diffuser that runs along the length of the wing. That would work far better from an efficiency and aerodynamics perspective, but still would be woefully less efficient than a 1-2 propeller design with larger motors and larger props.
It's pretty much commons sense.
@@scenicdepictionsofchicagolife Lilium vs. Archer vs. Beta Technologies eVTOL designs you are talking about?
ua-cam.com/video/x8OTNPugl24/v-deo.html
ua-cam.com/video/-nZ1MMzKfmM/v-deo.html
@@scenicdepictionsofchicagolife Idk I'll trust the scientists making the breakthroughs. Why be a naysayer just because you don't understand?
@@scenicdepictionsofchicagolife They probably compare to machines having the same STOL capabilities = huge wings. Small wings are the biggest obvious win. The second are tip-propellers.
Yes, many small engines are lighter than one big one, it is a basic scaling law.
Scientists love to cheat by creating meaningless synthetic benchmarks and try to impress audience that they have different practical meaning.
I love that you find so much new and interesting information. I just love this channel !
Glad you enjoy it!
there's a lot of focus in this space on making Uber's business model work but I can see this type of craft really revolutionizing general aviation and hopefully improving the safety record.
would bet that any air taxi service will end up being AI controlled, which really that's an easier problem domain than self- driving cars - that would mean only cargo weight will be passengeries
Exactly, check out the Blackfly - my favourite -
ua-cam.com/video/1ihlGGniYqA/v-deo.html
@@TheSulross I don't know how that would work with current ATC. Probably need the FAA to finally implement their Nextgen program because relying on speech to text for all of this would be a nightmare.
I know reliable robotics just has a drone pilot to handle coms.
Interesting presentation of the benefits of ESTOL over EVTOL for many applications.
Something I feel worth discussing: One of the big issues for current electric aircraft is the need for reserve endurance - if a problem develops at your destination airfield, you need to be able to fly to another one. These reserves are relaxed for helicopters as in an emergency, they are more likely to be able to land safely without an airfield. This means that aside from other advantages, in comparison with a conventional aircraft a VTOL vehicle should be able to make better use of its ultimate range.
Thank you for a very interesting video. I learned a lot from it.
VTOL needs to generate it's full weight in lift, something even the military tilt rotors are limited by.
@@pogo1140 Electric systems can have stupendous power to weight ratios compared to turbines or piston engines. In many ways it's a lot easier to build an electric VTOL aircraft than a classical rotorcraft. Energy density - range - is where the problems lie.
@@kitwolf2857 the weight is a massive hurdle, each pound of battery is lost payload
@@pogo1140 Compare Burt Rutan's Quickie and the Blackfly VTOL aircraft. The Quickie has an 18hp piston engine that weighs 36kg. The Blackfly has 16kg of electric motors that provide up to 336 horsepower, and the weight of the additional motors you need above those that are required for horizontal flight, is at least partially offset by the lack of landing gear. It's all great until you consider the low capacity of the battery - but this is a problem whether your vehicle is VTOL or takes off conventionally from a runway.
Now, imagine that you wanted to make the Quickie capable of vertical take-off and landing, you would need to install a bigger internal combustion engine weighing hundreds of kilos.
Short-range use is exciting! You can get 4 miles/kwh with USTOL (Ultra-short Take Off and Landing) if you can live with a 100 mile range, which is well within commute/recreational use! Even those high-maintenance, high fuel use helicopters never travel more than about 50 miles from base. I could see every TV station (if they still exist) ordering one to replace their "traffic copters", and Med-Evac very quickly shifting to multi-motor EVTOL (special case where VTOL is required).
What helicopter has a 100mile range? Even the earliest commercial helicopter had a 200+ mile range.
@@pogo1140 I think the OP was saying that most helicopters have a limited radius of operation - around 50 miles, not that they are limited to that distance.
@@pogo1140 "high fuel use helicopters" is what he said. Many helicopters have ranges like 200 miles or more but that's only in one direction. The helicopters he's talking about have to come back to base too, while using some amount of fuel at the mission site.
Best panorama of these i've red or watch so far. Very instructive and conclusive.
Yes, finally. Real efficiency improvements over getting a brick to fly.
This channel just keeps getting better and better. Keep up the good work!
I love this channel so much, keep going! I believe nothing can accelerate the transition to sustainable aviation as much as public interest and support!
Very good video as always!
I wanted to share some constructive feedback (hopefully!) though that your focus was more towards the takeoff performance than the range aspect in my opinion. (Ex: @6:15) Takeoff is such a small phase of flight that its power requirements are sometimes insignificant to the range.
It's clear that there are benefits to distributed propulsion. Since lift is proportional to the speed square, the relative velocity increase provided by the small propeller can give large gains in lift. Additionally, the Reynolds number is increased, and typically the CL is higher with higher Re.
But the research you link also shows some compromises that have to be made for each application. Despite having a higher thrust to weight ratio with the smaller motors, the aircraft was 11% heavier than the base aircraft. I cannot see the study, but did the aircraft use less power to cruise even when it weighed 11% more? Because that's what really would affect the range.
NASA in their Maxwell Aircraft were able to make the wing lighter and higher aspect ratio. The weight they saved from wing made the aircraft lighter overall even with the additional motors. Less wing area also meant less drag. So both high aspect ratio of wing and less drag help the aircraft in cruise. Thanks for you insightful comment
@@ElectricAviation That is awesome! Thanks for your reply!
Exciting to see how we are gaining new insights all the time. This really helps me feel more positive about the future that awaits my children. As always, I particularly love your delivery - concepts are articulated with incredible clarity and always with context. You have an exceedingly rare ability to communicate at this level and I often refer to your videos when I am preparing presentations myself (I have been in management consulting around the globe for over 20 years). Regards and thanks from Sydney - Dave
That is very kind of you Dave.
Amazing. We should really go for it. Less pollution, less roads, more flexibility, less traffic jam, more live quality, more terrain for agriculture, shorter commute between X and Y, lots of advantages. Smaller plains, less components, saver, cheaper, less CO2 footprint, more aesthetic, less dependence from large companies with goal to exploit you. Go for it!
Some info presented here are not quite true. Distributed propulsion usually performs worse than a single rotor if you consider propulsion alone. This is due to degradation of the flow characteristics on the blade due to smaller Reynolds numbers. I have discussed this with Dr. Nick Borer from the NASA X-57 DEP CTOL aircraft team, he specifically mentioned the smaller propellers used for distributed propulsion were performing badly, about 50% efficient, and that's why at higher speed they are stopped and folded. What the distributed propulsion actually does - it increases artificially the wing lift coefficient, the wing can be much thinner, having a lot less surface area, without a reduction in stall speed, but having much better high speed performance. Having a smaller chord wing, same wingspan, increases the maximum L/D and moves this maximum at a higher speed on the L/D characteristics. The smaller wing actually is the reason the range increases, not the multitude of propellers. The distributed propulsion is to allow the wing to perform at slow speed and have a relatively slow stall speed, similar to the original larger wing.
It makes sense though, also if we count drag those blades create, which is also a factor and yeah, 1 big propeller is intuitively more efficient
I wonder if this can be used not to fly slow, but to fly high? Basically, to achieve benefits from both low air density and relatively low speed (of the fuselage) to suffer from drag even less.
Love the depth and thought put into your content, ^oo^
Much appreciated!
thanks for showing DEP and boundary layer ingestion. i think that with distributed propulsion is more appropriate to use closed wings as joined wings or box wings because it gives more structural stability and reduces flutter, a trade-off of distributed propulsion.
Retrofit electric motors to an Antonov 2 biplane, which has incredible STOL capabilities. U Plane with 9 engines. Run-up of 6 seconds / 60 meters. MAX 2021 / TVS-2M... ua-cam.com/video/sI32NIvjvic/v-deo.html via @UA-cam
The next level is to replace the electric propellers with electric compressors, each directly connected to an oblong shaped bladeless fan built into the wing's leading edge so as to deliver the maximum laminar flow distributed across an optimized wing surface. So you are multiplying the lift and and mechanical airflow both. This should result in doubling the range again over the propeller design, allowing the electric system to easily beat the conventional one in subsonic flight. One could also incorporate a hybrid power source as well, making electricity onboard in an optimized RPM range for efficiency. The resulting efficiency in fuel consumption would approach an order of magnitude, the electrical approach allowing the optimal mechanical power distribution for a given form.
Another amazing video, thank you! Is there any research on the electrification of high bypass jet turbines?
There is plasma jet engines that has shown good promise
@@ElectricAviation Thank you. I am seeing some companies like Easyjet bringing an electric airilner to market and wonder how they will handle propulsion.
I can’t wait for someone to build a bush plane redesigned to fit multiple motors for super short take off and landing. Those bush plane pilots would know how to make the best out of it!
Yo - this dude presents his stuff really well👌✍
Just make a wing within a wing for take off, then it slides into the shorter cord for faster flying...
Not sure if you're the troll or me....but isn't that flaps 🤣
@@chrisglencross3867 Excellent remark. Yes and no. The flaps would extend the whole width of the wing, but the main wing would contain them as an envelope.
So they wouldn't exactly be flaps but a double corded wing...
Hope I'm a helpful troll 😅
See Scrappy.
@@gpaull2 It certainly has a broad cord lol. Broad cord calling Danny Boy 🤣.
Not fast enough but definitely short take offs.
Have you seen Mike Pateys transformer wing? I dont know how this would integrate with distributed propulsion, but it does nearly exactly what you are suggesting...
Edit: I see from other comments you are aware of it:)
Two things come to mind
1/ that trailing edge or pusher propellers would endear a straighter, more predictable flow over the wing, especially concerning the leading edge; further optimising Clmax
2/ and Im unsure the advantage of short take off, as the present experience deals with 'average' take off durations quite well,
... and hull insurance on STOL aircraft has proven in the main to be commercially prohibitive
ok make that 3 things ....
Fascinating videos, thanks
Glad you enjoyed it
Some very interesting information. Now the question is will an electric version of a turbofan jet engine be even more efficient? The electric motor would replace the axial flow jet engine. Keep up the good work. I love to see people thinking outside the box.
Nice job!
Excellent!
The biggest problem with eSTOL is safety. eVTOL machines are fundamentally safer, and there is a lot of designs that are optimally cruise efficient.
@ 5:27 is the take off formula, I'm doing this for me but it's information worth noting on
intelligent propulsion company, owned by rogers msuya, has invented something new that can generate electricity onboard... eliminating all hurdles facing the Electric Mobility today!
Great informative video on the advantages of distributive propulsion and eSTOL being more energy efficient than eVTOL. Will you investigate the PLIMP hybrid airship design and give the pros and cons of the design?
Video on Airship is in the works.
@@ElectricAviation Excellent….
Can distributed propulsion setup with small open propellers also achieve the high top speeds of a large EDF in forward flight?
Hey how do I get in touch with you?
VTOL would be great mainly for short hauls in the city and no transformer shape change necessary with the short distances. I agree STOL is way better especially without any transformer shape change which makes it easier to make, lighter and simpler. And you maybe can design STOL to near VTOL performance. e.g. A semi Black Fly idea with wheels and a slow landing speed that can easily stop short.
Fascinating drag reduction of the many movable,you have made a comprehensive history of aviation,you are a scholler of flight,good visuals 2 communicating the possibilities of a pure electric development of flight with little propeller flight ,straight up into the cruise multiple people/cargo load bearing capacity at highest speed ( :maybe capacitors could give batteries a boost on take off,or we could make big half mega bridge's into the ocean ,and shoot them of from ground batteries into full cruising speed,you could have bicycle s and car's drive into wings and battery,and are shot off the half bridges without there tyres/axel and chassis,batteries would be interchangeable with rentable wings
Very good coverage of this. VTOLs are likely destined to serve as urban robo-taxies rather than go to traveling vehicles, imho. Could you cover this aspect please?
Yes very true. They will remain, Within a city service or at most city to airport.
7:46 a tilt-wing version of this aircraft could be a very efficient EVTOL. Interested in knowing more abut this particular aircraft.
This makes total sense, and clarifies the thought I had for a very long time!
Always felt VTOLs are overrated. STOL removes a lot of complexity required for the VTOL functionality, like tilt rotors and bigger propellors etc.
Most people anyway won't be able to afford to fly in electric helicopters even if someone launches it. Making it simple makes it cheaper.
Very good content and analysis, keep up the good content!
I think VTOL are developed to be mailny air taxi. STOL cant replace them in cities.
But is VTOL with tilt-wing that much more complex? It seems to me tilt-wing could have almost same efficiency as STOL.
I imagine a hypothetical future where A LOT of road infrastructure could be replaced using VTOLs.
@@gianpietro6915 Agree. STOL can't do the air taxi role. I was saying mostly in the context of longer, intercity kind of travels, and a 'nearer' future use case
@@dejayrezme8617 I felt it adds quite a bit of complexity for supporting VTOL and hovering capabilities, and landing on a helipad or in a very heavily crowded areas etc. (Just my assumption - not much educated on this though)
I too wish if that hypothetical future of flying taxis could happen soon. But I'm not sure a whole army of flying taxis always roaming in the city sky is a great future to look forward to. Just imagine this - a 4 lane motorway could carry 1000s of electric cars and no-one will even notice, but if 1000s of flying taxis fill up the sky, it's an eye-sore and horrible experience to be underneath.
Beautiful CG renderings of one flying taxi in a city (showcased by every EVTOL startup homepage) is beautiful, but at any given time, in a big city there are thousands of taxis and Ubers running in close proximities. And unless something unheard of is invented, areal vehicles will have the sound of wind, and will have to keep some distances too... So chances are, it'll be limited to only the top rich few for practical use(do you think/want millions of people to take it?)
Maybe decades later, when the entire sky highway infrastructure is precisely managed and controlled by AI and AI alone (must be un-hackable too), and aviation without much influence of weather is achieved, I'm skeptical.
(Omg it was quite long!)
@@JoeMathew Think about it. The axis has to be strong enough to support the weight of the aircraft at 3-5g meaning support the weight of the aircraft and payload x 5, and all of that weight increase can come in .5 seconds.
Then the two rotors have to spin at exactly the same speed with exactly the same blade pitch.
If one motor fails, the plane crashes.
If you use more than 2 rotors, that means more weight, more power needed, more batteries more weight which means more powerful motors which draw more electricity which means more batteries which means more weight and so on.
Thank you for your excellent work 👍👏👏👏... you have basically insinuated that we are about to see micro airports in the middle of bedroom communities around the country... quite and clean aircraft will change air travel completely
Yes, soon hopefully
It would be interesting to see if a craft with a large rotor that is driven by small propellers along its length would be worthwhile.
Maybe with a conventional combustion engine which increases in efficiency with size. But as stated in the video, smaller electric motors are more efficient than larger electric motors.
Distributed propulsion simulate what a bird wings would do if it was flapping its wings to get lift. The airflow is evenly distributed over the whole wing and not just a section of the wing. They should design bigger aircraft with this in mind.
I did watch your video on fuel cell flight, and still don't perceive you gave a fully realized evaluation on that, but this was informative (for me) about take offs (?)... Did you say there's a larger drag coefficient at certain heights, weights & speeds?Also still also a matter of public access, when it comes to vtol flights without runways, & nothing is wrong with romance... It's romance which is correct.
Please provide a reference for the Takeoff Length equation 13.WingLoading/(TtoWt*Cl)
I see a lot of companies pursuing VTOL and think of the wasted energy. VTOL is unnecessary in most instances and only serves to increase the cost of flying. I am excited for full electric aircraft, however I am impatient. Can you do a video analysis of Pipistrel's Panthera Hybrid system?
Yes Panthera has been on my radar because of it great aerodynamic characteristics. I will do a video on it at some point
This guy: Talks in depth about the science behind and efficiency of battery powered aircraft
Also this guy: Refuses to replace the dying battery in his smoke detector
amazing
would the lift be higher when the props are located above the wing rather than below as with the NASA design?
This is a remarkable video. There is clearly a very good business case for the light private pilot aircraft segment. Why is this not being pursued?
Also, can you state what each of the prototype EV aircraft you were showing in this video are? Probably with a link. What was that dual wing, multi-prop one with the tricycle landing gear? And the DHL one? Would like to know who's behind these designs.
I get the feeling that many developers are approaching the design aspect wrong, based on what you're saying. Someone should start by just designing the optimal airframe and propellor setup, and work back to a working aircraft from there. And all propellers should have the capacity to stop and fold along the motor in order to allow more efficient travel at cruise speeds and altitude on just one or two motors.
Thanks. The aircraft is Emotion
www.emotion-aircraft.com/aerodynamics
The DHL one is Eviation Alice
@@ElectricAviation Is it really a German company? Just like Lilium? This is going to be exciting!
What about the drag all those propellers create?
What about speed? How is it affected with the number of propellers?
How does blown air increase lifting coefficient? Thank you
Nice!
Do you think Joby and Vertical will be able to take off and land like a conventional estall aircraft where it’s appropriate to do so and save some power for longer missions
They can certainly land at low approach speeds. In vertical VAX4, it would make their vertical fixed rotors redundant
Check out the XTI Aircraft Trifan design....gas turbine driving a generator that powers motors driving ducted fans which rotate for either vertical or horizontal thrust. XTI plans to replace the gas turbine with batteries when battery energy density improves. Full disclosure: I own shares in XTI aircraft.
I know Trifan and I like the aircraft very much. The reason it caught my eye was because I did an independent study for VTOL and came up with three props, more or less the same dimensions as E fan
So, using 100hp motor with 8' dia. prop, would burn more fuel than four 25hp motors, each with a 4 foot diameter propeller? Would the propeller design and rpm's make a difference?
It depends upon the RPM. Please watch my upcoming video, because I will dive into the details and hopefully will be able to explain it better
Seems like it would be worth while to create launch assist drones that attach temporarily to the craft, and they would be designed to provide one minute of thrust before they disconnected and fly back to be recharged for the next launch.
Anyone doing that sort of design?
What about size of the aircraft? Is there an advantage/disadvantage scaling up.
With electric motors in place, you are scale independent. With IC or jet engines, you lose efficiency as you scale down
Yeah, but in an STOL you are still taking off and landing on a runway, which is existing infra usually built far outside of the city. And even if you start building custom runways of let's say only 50m you still need empty space for approach, and for city travel that's still a lot of prime real estate space dedicated for landing infrastructure.
The reason people are excited about eVTOLs is specifically that it enables point to point because the landing infrastructure is so much less involved. Nothing to do with flying cars.
Interesting
What about having a ICE running multiple propellers, say 4?
ICEs advantage is in the fuel. the rest is poor efficiency. Because fuel is ~50 times more energy dense it just allow ICE engines to linger and show they wastefulness :)
the problem is the gearing to deliver power to props
its weight, cost, complexity in servicing
Good thought. I at first thought kinda the same thing, but ICE has problems (beside the lack of biofuels and noise).
If individual engines, they are heavy, complicated, and inefficient. If one engine geared to multiple fans, it could work but would add complexity, maintenance cost, and a failure could be deadly.
Perhaps best would be to use an H2 or Methanol fuel cell if you need maximum range, but for everything else I would think an electric battery is better. (Also, if you use a fuel cell you can always upgrade to batteries when they become higher power density than fuel cells).
For small planes, people have been moving away from multiple engines for years because you don't really see the payback in performance. for the weight and complexity.
You'd be better off adding a diesel or turbine range extender if you need more than what a battery can provide.
I am a SEL pilot. When engine goes out, pull the sheet and set Vy and look for room to land.
Solar powered electric airships (rigid Blimps) could take over a huge portion of freight flights point to point with almost no infrastructure. I’m amazed there is so little interest. Point to point at 120 mph with no wear and tear or clogging of roads would be extremely helpful. Quiet and no pollution also good. Modern technology would mitigate hydrogens flammability as it has lithium.
Dear Electric Aviation, we are big fans and followers of your work, we are currently working on a project where we feel that your expertise could be of help, do you ever do any consultation work? please contact us as we would very much like to speak with you.
I have a full time job so I cannot do consultation work as such, but it would be interesting to exchange ideas. You can reach me at Haroon_Junaidi@yahoo.com
I wonder what would happen if you put little propellers on a big propeller.
i am trying to imagine how it would look like....
A propeller is in general good in some regime and bad in rest of regimes. Mostly like a wing. Like the wing is very sensitive at what you ask it to do and adding complications on it guarantees to make it worse. Just like the wing. That's why props on wings are in general bad. But some dream... Like the guy with this channel.
some helicopter propulsion systems have envisaged such a proposal
I think one of the entrants for the Sikorsky prize, a human powered helicopter to fly in a figure 8 pattern, used a pedal driven generator to a tip mounted propeller.
@@Soothsayer210 I mostly meant it as a joke...
But now that you ask, I'm thinking a barrel shape, with propeller blades spaced evenly along the outer edge, actuated to vary their pitch, with a ring of propellers at the top also actuated.
It would take off vertically pointed straight up, using the many small propellers for direct lift.
It would then start spinning the entire thing so the outer propellers would produce lift as well.
At high horizontal speeds, the small propellers no longer produce thrust in the direction of travel, they are used exclusively to generate spin for the larger propellers.
Inspired by the flying cylinder frisbee sort of toy. You throw it like a football and it gets lift from spin.
It's probably a terrible idea, but with enough thrust SpaceX got a water tower to fly.
Interesting. How would you drive the propeller-on-propeller? Could it capture vortices? Hmmmm....
I'm confused.. if distributed propulsion is great for range, why does the NASA X-57 Maxwell only use it for take off (and landing)?
Its great for acceleration and take-off and landing. Once cruise speed is achieved, you can use either all propellers at low speed , but even better is to use the large props if any for more energy efficient cruise.
blowing the wing with the motors allows them to run a much thinner wing than would otherwise work at low speed. That wing is much more efficient when they're at cruise and at that point there's enough flow and lift to support the aircraft.
The big ones on the tips are also counteracting vortexes that form on the wingtips, so that's also adding some efficiency. Hence why the main props are much more outboard than they normally would be.
@@AntonEMaes Thanks. Most of the aircraft in the video are not examples of distributed propulsion enabling thin cruise-efficient wings (and therefore long range). Love this channel though.
Luv, the channel . Btw, that wasn't a Mig-21 .
Thanks. My apologies
Very interesting. The lack of energy density in batteries is certainly forcing people to squeeze the sponge hard for every last drop of advantage. I wonder what would happen if tomorrow we had a game changer where we saw density at a 1000 times what it is now. It would probably put efficiency chasing on a back burner for quite some time so maybe the lack of density we have now drives a science benefit in other areas we would not have otherwise had.
That's certainly physically possible! I think the physical limit would be a fuel cell, because you still need the Hydrogen to hold the electron... essentially a fuel cell.
Don't forget to replace your battery in your smoke detector.
What's the model name during the 5:15 to 5:28?
Its Emotion
www.emotion-aircraft.com/aerodynamics
If you use Edison generators and dynamos rather than battery powered electric can allow much more powerful electric motor.
Please clarify what you mean when you say "5 times more propulsive efficiency" with distributed propulsion @6:58. Propulsive efficiency cannot be greater than one. Do you mean a 5 percent improvement? Thank you.
Lets say the propulsive efficiency of an aircraft with one larger propeller was 0.15, than 5 time propulsive through multiple small props means efficiency of 0.75
@@ElectricAviation That is not a realistic example. Propulsive efficiency is the ratio of the thrust power to the mechanical power delivered to the propeller. Even a single propeller aircraft should have a propulsive efficiency greater than 0.75.
Is propulsive efficiency defined differently from propeller efficiency in this context?
Exactly. :)
Does electric propulsion have anything to offer sea planes ?
I have done a whole video on it.
ua-cam.com/video/_D4e3V4FP9M/v-deo.html
@@ElectricAviation Thank you.
I really do wonder if the best combination would be a ground effect aircraft with hydrogen fuel cell electric propulsion for at least 80% of propulsion needs of 50+ person passenger aircraft... 🤔🤔🤔
Can I help you with the Edison generator and dynamos to power your plane without battery powered . Fully unlimited electric power planes.
Time someone’s makes a super high bypass single shaft electric monster to rival a ge90’s record 134,000 ft lbs of trust
Adwantages? There’s no V in that language?
They need to make them quieter.
God: the only way multi props will work & b efficient is in the FAT thick wing trailing prop design & the air-foil prt shape of the wing is the channels between the props.
Car's flying cattermerangs,gigantic shipping crude oil splerter's with paragliding sails/giant kites pulling them along in part with shipping lanes battery packs ,improving the sea and the cities,and the air
Electra Aero 😍
🤩
My hope is a combination of small STOL aircraft with AI control system would liberate humans to live in smaller towns. Current flight tech makes travel from smaller towns not economic, with most only achievable with large Govt subsidies. If the cost of the flights is halved, likley even more with the low cost of electricity and much reduced maintenance of elctric motors compared to ICE planes, chosing where you live can be much more about lifestyle.
The F-104 used blown flaps? Who knew!! 🤗
Just like the MIG-21...otherwise the landing speeds were stupid high...I have flown it...
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Do not over amp the motor use the Edison generator for electric power source. An old generator can be converted to Edison power by chiseling off the Tesla magnets and leaving the Edison magnets on the generator armature. A pre 1974 car generator can be used count the armature magnets and divide by six and chisel off one sixth and leave one sixth on and then off and on until you have chiseled off three sixths and left three sixths on alternating on and off. The generators are motors and will spin as you assemble the generator. The generators self spin unlimited generation of electricity. You have replace the commutator brushes. Add inverters and transformers to deliver power plant power or house current. But 12 v power continuous peak power or 110v AC is immediately available for airplanes power for an unlimited time . Redundancy is safer.
if batteries are designed to be easily swapped out then electric vtol air taxies could become a thing - every air pad could have charged batteries waiting to be swapped in
@Electric Aviation If distributed propulsion is more efficient why Airbus and Boeing are increasingly making commercial airplanes engines bigger and bigger ? In the past they had 2 or even 3 engines per wing and now they have just 1 big engine per wing, so if distributed propulsion is more efficient, Why they didn't made the jet's core smaller (in order to increase the bypass ratio) instead of making the fans bigger and leaving just 2 big engines ? And now Why are they making them even bigger instead of putting more engines ?
It is because they are only concerned with jet engine efficiency. With higher bypass ratio, they can get higher efficiency of the jet engine. Over here we are discussing propulsive efficiency, in which the rotor downwash is directly blown over the wing. In commercial airlines, the engines are hanging below the wings, which increases the wetted area and hence drag. However, the make up for it with improved jet efficiency.
Hello,
At 3:22 you say that smaller motors have high trust to weight ratio, but when i look at another video you put online:
ua-cam.com/video/O0vQbSfuufE/v-deo.html
And you go to the stats at 04:24 I see that the trust to weight ratio is lower.
Can you or maybe someone else explain this to me?
Best regards,
Jan
Jetoptera: propellers are so passe.
I listened to this video hoping for some kind of explanation for the claim but heard nothing.
Therefor, I believe that in the absence of rational scientific cause, the claim is bogus.
The video did mention what I consider critically important, which is the calculated thrust to weight ratio of the engine and aircraft.
But, I heard nothing about why distributed power should be more efficient or be reason for a superior thrust to weight ratio.
I will say that AFAIK,
fewer and larger props and engines do run into certain limitations...
The propeller tips must not travel faster than the speed of sound.
The propeller must be optimized for a particular speed.
An optimized propeller will account for the different radial velocities closer to the hub and along the propeller to the tip.
Of course, an optimized propeller will have an airfoil shape.
There can be additional features that can help propeller efficiency like ducting.
Maybe the idea is that with smaller propellers, the extreme difference of the propeller's efficiency from hub to tip is possibly less, but that might only mean a less optimized propeller shape might be required.
It might mean that with smaller propellers, the propellers can spin faster, but that's hardly related to propeller efficiency which also depends on airfoil, angle of attack, materials and more.
So, based only on what is in the video, I don't think that its claim is accurate.
Need proof, or at least a sensible argument.
Until they can build reliable safe and stable batteries with 12,000 watt-hours per kilogram, electric planes are just toys for rich people.
Until they figure out how to mass produce graphene for batteries electric vehicles are just too impractical.
The more motors and propellors you add the more weight and drag you add. So adding a bunch of motors defeats all objectives. Thus guy does not understand why early aircraft had many engines. It does nothing positive once you meet redundancy requirements.
I've never understood this concept.. why multiply the drag penalty of one small propeller 10x times when it is well known bigger propellers are more efficient... efficiency is a much bigger deal with limited on board energy. This does NOT have better propulsive efficiency. Whoever told you that is either full of shit or has no idea what they're talking about. If this wasn't the case, then turbofan engines wouldn't exist and the fan part of the turbofans wouldn't keep on getting bigger and bigger.
That is because they are optimizing jet efficiency ahead of propulsive efficiency. Larger jet engines are more thermodynamically efficient. Larger bypass ratios give better fuel economy. This is different
@@ElectricAviation not at all different. Thermal efficiency of gas turbines increases maybe in the single digits of percent. The larger bypass ratio is one thing, but that if just for the turbojet. Turbofans have large bypass but also are essentially just extremely large turboprops. So same principle. I'm not sure how that's confusing. Thermodynamics works just the same for an electric motor as it is for a Brayton cycle gas turbine - and theyre both driving a propeller / impeller.
There is a reason small turboprops burn almost as much as larger ones. Distributed trust is a mockery of physics and this is ty end of discussion. These stupid designs will never fly or be commercially viable. Mic drop.
Electric motors are not called "engines"!!!!!!!!!!