“Hey guys, don’t worry, we’ll give you a formula sheet on the exam” The formula sheet: Momentum = mass • velocity The Exam: If we were to take a Cessna plane, and convert it’s fuel source to battery power, what would be it’s ideal flight time?
Idk. Approx 45 minutes to an hour 20. lmao. Add solar panels to wings and that time would increase to approx 2-4 hours. But they might have to remove bathrooms from the plane to compensate for the weight.
Using a hydrogen fuel cell. It works sort of like a battery but uses hydrogen and oxygen instead of two metals. It is not an internal combustion engine.
This is the kind of math I wish I could do, just plug is equations that I seem to know off the top of my head and get the needed answer like its a trip in the park. Too bad it isn't like this at all Dx
This “real engineering guy” is just talking baby level physics, it’s not that hard but he made the equation signs so complicated, try to make him look smart, Eh~
I absolutely love your videos. They never feel rushed but rather polished. Yes, I read many books to learn the concepts. However, nothing will link these concepts to real life like the way you do my friend. Invested in Brilliant after seeing you recommend it with heart countless times and it is worth every cent.
Real Engineering I really enjoy watching your videos they have taught me a lot about engineering and physics they are always teaching me something new, have you ever thought of making a video about the mechanics of nuclear reactors?
The video are good, and I do appreciate them, just that sponsorship kinda make me very uncomfortable watching this, it feels like being brainwashed, pateron kinda feels better, also, What's with the similarity to whendover productions
There's a joke about Belgians I particularly like (I'm Belgian btw) The Belgians invented an electric car. Costs 1 million dollars though. 100k for the car, the rest for the extention cord.
Europe is a strange continent. In several recent video games the Russians are the bad guys. Why? If you make the French the bad guys, they won't buy your game. The Russians don't mind, they will buy your game anyway. In the same way Belgians don't mind being surreal idiots... Well, because basically we are Lol
Did you account for the efficiency differences between fossil fuel powered engines and electric engines or the fact that liquid fuels are used during flight which lowers the planes mass as it flies on over time vs. electric powered aircraft which don't lighten their load with duration?
Yeah, liquid fuel just makes a ton of sense for airplanes. They should just master and find ways to convert electricity to liquid fuels efficiently. That, or find ways to make solar energy or wind energy directly convert the power to create a liquid or solid field. I know they kind of already do this for some rocket fuels etc, but I haven't seen it in a way that would work for planes.
The main problem is the sustainability. It doesn't *need* to be electricity. Quite frankly, I hope we can get some sort of biological solution to the problem. I heard that some scientists were able to turn genetically modified switchgrass into a jet fuel precursor, which would be really neat if it could be scaled.
Hold on a moment... as the conventional aircraft burns fuel, it also becomes lighter. The electric aircraft's weight would remain the same. The performance of the conventional aircraft would increase over time as the amount of fuel on board burns and exhausted through the engines.
That's true. But turbines have a vastly different efficiency curve at take-off (max power) and cruise (around 60% power). Turbines are burning inefficiently while cruising, sometimes their carbon footprint actually rises at altitude. Hybrid-electric, battery/fuel cell electric do not have that issue.
+Ohnonomomono The reduction of fuel efficiency with increased altitude is due to air density change, as described in the video. It applies to all aircrafts. But yes, different types of jet engines have different ideal altitude (ie. air density) and air speed.
Maximum efficiency is at full power, and low outside temperature. Calculations here are perhaps true, but definitely not used in aerospace engineering in terms of performance. Check out the Breguet Range Equation. web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node98.html
All math leads to solving real problems... Can't do calculus without algebra. Can't do physics without calculus. Can't do linear algebra without calculus. Can't do differential equations without calculus. Etc
Basically he’s saying battery energy density isn’t dense enough currently to be a solution unless someone improves battery density enough to become an answer.
@@DylanBegazo that's good if that's the only problem because as it stands everybody is already trying to fix it. Tesla, Panasonic, Samsung, and several others are already racing.
Starts watching. Sees explanation about batteries being 40x heavier than kerosine. Makes sense, I'm happy I know this now. But starting at 2:12 I felt more and more stupid and I should go back to my coloring book :(
Don't worry it is all fluff to lengthen the video. The main point here is that batteries will not work for long range planes. However, I think the electric planes will be the future. The thing this video is missing is hydrogen, hydrogen fuel cell systems. Power density of this just dwarfs any kind of fossil fuel. If we go overboard with renewable energy, we could be storing them as hydrogen.
It's funny because the US actually tried to do that. The main issue though was thrust to weight, as a nuclear reactor is wayyyyy to heavy for a plane, and thr idea was to basically just heat air to create thrust.
@@Randomguy-wd5lw Actually Russia and the united states both put reactors in the back of planes to see if they could carry the load. The problem just became pointless when you could nuke your enemy with ICBMs much cheaper and easier.
Us had a plane with a reaktor onboard but it did not power the plane. The Russian actually had a working plane that was powered but the nuclear reactor. The main problem though it was puking out contaminated air and it had so little protection. It did not even protect its own crew..
5:20 “Doubling the mass will increase our power requirements 8-fold.” This is incorrect. The factor of 2 in the power equation is present in the calculation for both the lighter and the heavier plane, meaning it can be factored out. Doubling the mass increases our power requirements by a factor of 4.
Glad not to listen with all his fluff to lengthen the video. He shot himself on the foot with all the equations. However, I think the electric planes will be the future. The thing this video is missing is hydrogen, hydrogen fuel cell systems. Power density of this just dwarfs any kind of fossil fuel. If we go overboard with renewable energy, we could be storing them as hydrogen.
Very informative. Another interesting point is that airplanes get lighter in flight as they proceed, whereas battery mass doesn't change. This results in airplanes departing and arriving with the same mass. On conventional aircraft that would be an overweight landing. Battery powered aircraft would need reinforced landing gear and therefore have added mass
Marc Wenger Maybe the plane could drop some of the batteries 2/3rds of the way out on a paraglider or something ;) To do something like the 747 to 787 electric would require a massive rethinking of the whole aircraft so it’s not totally unreasonable to imagine something crazy. I do think that long haul airplanes will need some kind of fuel for a long time though. But maybe we could gain more efficiency with some kind of hybrid design. If we can cut fuel consumption enough we could use biofuels.
@@auspiciouslywild We've been using hybrid design for a long time now. The current 787 Dreamliner is the closest thing to an "Electric airplane" we've ever built on the scale of a commercial aircraft, as well as the fact that it is the most fuel efficient large airliner ever created. Compared to the Airbus A380, which is its main competitor, the 787 was shown to be about 60% more fuel efficient.
Keep in mind that, statistically speaking, more than 2.9% of males portray themselves as female online. So, that gives us a negative value for female representation here. Which is about right. But I'm sure someone will stop me and tell me that umpteen million women really are interested in engineering, it's just that this channel only allows males. Or something about privilege.
The calculations could be simplified by working out how much thrust an aircraft needs to take off, climb, and maintain level flight, then work out how much power is required to generate that amount of thrust, then multiply it by how long that level thrust will be used, then add those energy requirements together to calculate the total energy needed for a given flight
one thing you forgot: for prop aircraft, fuel usage is proportional to power for jet aircraft, fuel usage is proportional to thrust. that is why, when determining maximum range, you look at the power graph for prop aircraft and the thrust graph for jet aircraft.
@@jonibeYT jet aircraft turn fuel directly into thrust by spitting the burned fuel out the back. Prop aircraft turn fuel into thrust indirectly by spinning a propeller. This makes them less efficient when the air is thin, or when the plane is already going fast. flightacademy.info/aviation-power-curves
@@josiahmartin329 Jets dont spit out the fuel but they heat up air which expands and that way gets pushed out of the back. Maybe the point is that in thinner air the jet can heat up the tinier amount of air more which results in the same thrust while the propeller is limited by its tip speed and the sound barrier because if that isnt the case the propeller can just spin alot faster because of the reduced drag
🔴 It cannot be a "Jet" if it's electric, by the very definition of the term, "Jet"- engines burn fuel. it would have to be a 'Ducted-fan' configuration.........
@@joshhayl7459 Jet has many definitions, and while on its own the word is colloquially used to refer to a aircraft powered by "jet engine"; there are words that are used with it to denote a more specific meaning, for example "jet propulsion", "jet stream", "jet engine" - so adding a qualifier like "electric jet" is sensible and understandable to a lot of people. According to biologists, some cephalopods utilize jet propulsion to quickly move around in the water. Don't try to tell me they burn fuel too ;)
@Jan Stankiewicz , 🔵 Perhaps you could provide me with a link to an "Electric jet aircraft", as I am unfamiliar with anything that fulfills that technical-description.
@@joshhayl7459 I thought they were only a concept, but I found a video of a working prototype just by googling. It's called Lilium Jet. Link below. In return, would you be so kind to provide me with a link to a definition of jet that specifies it needs to burn fuel? th-cam.com/video/mjAJWrraTKs/w-d-xo.html
Hi, good video but I noted two small mistakes. 1) (delta x) /t = v, not delta v. Delta v represents the acceleration, not the speed. 2) Doubling the mass, will not increase the power demand by 8. It will increase it by 4, even though there is a 2 factor in the equation. Let's say for example that P1 is the power of the light aircraft and P2 is the power of the heavy aircraft and that M1 is the weight of the leight aircraft and M2 is the weight of the heavy aircraft. If the heavy aircraft has twice the mass of the light aircraft, it means that M2=2*M1. If you plug 2*M1 in the equation to find P2 and then you divide P2 by P1. P2/P1=4 (the factor 2 cancels out).
Wrong! Vector-v of the standard delta within the given range of p - xrt120 over vex factor 2, is the precise analysis of any range given at par levels of accepstance, with all guidelines of sub-par equasions at exact values of 10, but not exceeding 12, but between values of particle norms of anything in the middle of whats not core value at relative transitioning. Depending upon what is, might be or could be, given everything it is and should be.
Doubling the mass does not increase the energy 8x. Since no matter the mass of the plane the mass square is always doubled (for e.x. 1^2=1 1x2=2 2^2=4 4x2=8 8/2=4. The energy increases 4x.
In reality increasing the mass seems to have little effect. A 747-SP weighs four times as much as a737 MAX, but only has three times the engine power. They really screwed the pooch on this clip.
Another thing worth pointing out is that the amount/weight of the kerosene decreases as it is being used while a battery pack weighs the same wether it's at 100% or 5 %
There also is a turnaround problem as well. Fossil It is very quick to refuel and easy to drop fuel to lower the weight of the plane in emergency situations. both of these problems would need solved as well.
Could have standardized battery packs, swap them out at the airport for them to charge and put a charged one in, take right back off. Like propane tanks. That could theoretically be even faster than refueling.
GabDubé yes, i didn't say jet a is not volatile, but no one is in a hurry to swap it around, imagine if u want to swap the batteries they have to be removed by a forklift of something, which increases the danger of the batteries being mishandled
5:20 "Doubling the mass will increase our power requirements 8 fold". I might be missing something, but how does this come out of the equation you just showed? I realize there is a 2x at the front, but this shouldn't change what happens when you double M_plane. For example, assuming the value of all other variables is 1 (to make this easy) you are simply left with 2*M^2. If you plug in 1 for M you get 2, if you plug in 2 for M you get 8. This is a 4 fold increase.
Came here to say the same, Friedrich Nietzsche, I think you are absolutely right, the 2 will not lead to an 8fold increase, it's only the square that counts! Great video though.
Actually, the reason is due to the need to also increase the size of the wing to accommodate the lift required for the increased mass, or to increase the speed with the same wing area. And if you fly faster, you are using the energy at a faster rate over a given distance. The conclusion stands, but it is embedded in the equations.
@Bob Saget Say you had M=2, you would get 2*(2)^2 = 2*4 = 8 And then M=4 would give 2*(4)^2 = 2*16 = 32 Double M, and you quadruple the result, because it is proportional to M^2 and multiplying by any constant will have to be done in both calculations. 2M^2 is proportional to M^2, and 43875M^2 is proportional to M^2. Any constants involved don't change that, because they remain constant.
But he just says double the power not double the mass. This is the difference between 2*m^2 and (2m)^2. And the former is what he puts into the formula so I don't get why he would say times 8 when that doesn't line up with the actual equation given. Plus at 5:06 he directly says "double our power requirement," and not "double our mass and multiple by 2 after." And before someone says something about the mass of the fuel, is doubling fuel weigh really going to double the plane's mass?
Actually, the reason is due to the need to also increase the size of the wing to accommodate the lift required for the increased mass, or to increase the speed with the same wing area. And if you fly faster, you are using the energy at a faster rate over a given distance. The conclusion stands, but it is embedded in the equations.
One HUGE drawback of such a low power density energy, is the landing weight since you don't loose significantly weight over time. On traditional airliners, you can't land safely with a full fuel tank. You can't either dump the batteries in case of an emergency. PS: Love your vids !
nowadays modern airliners can land with full fuel tank, I learn this from @Mentour Pilot . He says fuel is really expensive to an Airlines, they really want to keep it if possible.
The problem is more that when you have an emergency, you really want to dump fuel and return, to set yourself up for an as easy landing as possible. Would you go for a severely overweight landing with inoperative slats, flaps, spoilers or thrust reversers? No, you dump fuel.
xponen_ not according to the tcds and far regulations they can't. All aircraft whose takeoff weight exceeds maximum landing weight are required to have jettison systems, (which all modern airliners have) because of the simple fact that they can NOT land with a full fuel load.
It’s a good point but just a bit of inside info. On aircraft where Max landing Max is less than Max take off, you have to achieve that mass to land with in normal operations. However, you absolutely can land over weight, as long as the landing performance allows it will be perfectly safe. An instance would be if you are required to land immediately, such as smoke on board. Commercial Aircraft are tested to land at Max take off weight for safety reasons. For instance a serious fire after take off that requires an immediate landing. Normally post any over weight landing, an inspection is required by local engineering on stress prone areas. It’s actually about preventing long term stress from repeated over weight landings rather than damage from a single landing. Hope that provides a bit of colouring in.
Yeah, they made a mistake there. The 2x is a constant factor that would be in the before and after values, just like the gravitational constant, etc. Should have said fourfold.
Yeah, the explanation is clearly wrong. Examples: If we reduce the mass by square root of 2, squiring mass would be half of original. Now we add the 2x (that is wrong) and the power didn't change. Or if we don't change the mass and square them mass (1^2) and after that multiply by 2, we have 2x more power consumption without changing any variables.
@@JoshyDMCOfficial Very true, more ppl die in car crashes happened than plane crashes. The plane crashes just look more tragic Edit: it's actually more tragic
@@saocxdc210 with a car crash, there is always that hope that you'd live and people don't usually see it coming, or they do, but still maintaining hope. With a plane crash, well it's hard to have any hope when a typical plane crash kills everyone. A plane crash though damn!! Must be fucking terrifying. Fuck, it happens in areas that cars have no business being. Nightmarish areas that you wouldn't hell dream of journeying with a car. My lord yo!
Until NZT48 is made I'd suggest large quantities of adderall and wasting at least one semester in a engineering program at a good school I dropped out at the first semester but I kinda got it (full disclosure tho newton is my great×8 uncle tho)
Ketamine, you must take. Run over minorities in your 2001 Honda Civic, you must. Recognise the legitimacy of the State of Israel, you will not. Make sense, the equations will.
Glad not to listen with all his fluff to lengthen the video. He shot himself on the foot with all the equations. However, I think the electric planes will be the future. The thing this video is missing is hydrogen, hydrogen fuel cell systems. Power density of this just dwarfs any kind of fossil fuel. If we go overboard with renewable energy, we could be storing them as hydrogen.
I understood it to mean doubling the already doubled mass would result in a factor of 8 times the Original M^2. That's how I read it...but I don't know if that's what he intended or he really made an error. Great info though.
111danish111 how? When fuel is used, it's gone, which means the plane is lighter, meaning g it can fly higher and faster which increases the range. Just like your car. Remove weight=better fuel economy
In your formula, you forget that lift has to do with the airplanes wing area, not just the wing length. On top of that, is has quite a lot to do with the airfoil shape, so lift can actually be altered in many ways just by changing the airfoil cross-section, the sweep the wing has (in order to reduce the vortices on the wingtips - also done with winglets and sharklets), and by delaying the separation of airflow before the trailing edge. It has to do with angle of attack and whatnot. The issue with wings is, they're made sturdier by having the fuel stored in them (in layman's terms), so eliminating any storage of fuel in them can actually be detrimental to lift, due to the fact you'd have to choose a shape that is more durable, but is much less aerodynamic. Also, when you use the word "leading edge" in an aviation video, it tends to confuse people, as it has a whole other meaning in the aviation field.
Wrong. At 2:30 the work is the dot product of displacement and the force. For an horizontal flight the work of the lifting force is ZERO. en.wikipedia.org/wiki/Work_(physics)#Mathematical_calculation The only forces that need work is the drag. The wing are not perfect and generate a certain % of drag proportional to the lift. It in the range of 1/15th to 1/20th. en.wikipedia.org/wiki/Lift-to-drag_ratio So somehow some of the drag is proportional to weight but all your calculations are a bit strange... Of course this is not all the drag. There's some because of frictions, the aerodynamics of the fuselage...
Yup, very strange equations indeed. My eyes began to fill with blood when he divided DeltaX by just t, not DeltaT (it's very ugly way to write derivative!), than he named velocity he got with DeltaV, which is totally wrong, there should be just V. But the final straw was to consider lift, not drag, you're right.
PolarBearVodka007 That's the whole problem this video tries to solve... I would do it another way. Imagine you have a working plane and add extra weight. You have to increase lift. The best way is to increase the size of the wings. Of course this also increases the weight. Also some structure is needed. At the end of the day you have to add even more wings... Conclusion: it's not really linear. A point that was not taken into consideration is the volume. For the same energy you need a lot of space. Electric planes are possible (see solar impulse) but at the cost of huge planes and very low speeds. (One of the trick is to use solar power to increase the energy available and also increase of altitude to store energy during day and going down slowly during night)
Another point is that the equation has 1/L^2 factor but if you increase weight a lot you have to use bigger wings or you just can't take off and cruise at decent speeds even with flaps. To simplify things let's just say the lift doubling needs a doubling in wings area so an increase of sqrt (2) of L. So doubling mass will x4 the numerator and x2 the denomitor. At the end you just get x2 power with his equation...
There is another issue with Batteries, specifically with Lithium-Ion: Capacity decreases with use. Every time you recharge the battery, just a little bit more of the battery's capacity is lost, and thus the next charge won't last as long for the same amount of draw. It might not be noticeable at first, but if your Cesna is barely making it's trip on a single charge, eventually the plane will lose all power in the middle of landing, and after that it starts dying mid-flight. And if you somehow not died at this point, the battery won't hold a charge at all. We've all seen this with out smart phones. So you would only get the maximum range out of a battery-powered plane so many times before that battery needs to be replaced. And while battery recycling is a thing (and is why, for cars and boats at least, there's an additional fee for buying a battery if you aren't bringing in a dead one), there is still an inevitable waste that will happen.
Which is important as the plane is expected to have shed that weight at landing time as it makes landing easier and safer with battery powered planes you would not only have to overcome the energy density problem but also the problem of having to do redesigns to fit with the fact the plane will be the same weight when it lands as when it took off.
Maybe a good transitional technology would be to install a reforming unit aboard existing aircraft to make hydrogen from gasoline, which would then power a fuel cell. Then, as hydrogen storage tech got better you could just use the fuel cell. A small battery bank would be used for takeoff power.
Great video, but in my opinion two important points were missed. 1. Jet engines are really bad in efficiency when compared with electric engines. Jet engines using kerosene can reach up to 60% of the fuel beeing converted in kinetic energy. As for electric engines that number is quite close to 100%, so in the “back of the envelope calculation” u could remove about 35% of that kerosene and still have a good safety margin. 2) Fuel mass in airplanes varies with time, wich is quite good for them, and doesn’t in electric airplanes. Love the channel!
Bit depressing, isn't it? Each to their own, but we've clearly got a long way to go as a society. There's an awful lot of wasted potential being untapped.
I don't mind women being or not being interested in engineering, but people claiming we're the same are just wrong, clearly women have other interests.
One important factor you also forgot: Charge time. What would the charge time be for 200,000kg worth of batteries? "Welcome to London, we'll see you next week when the plane has recharged" 😂
Same as your notebook battery, car battery or any other battery (roughly one hour assuming good enough power source). Whether you charge single cell or thousand cells in parallel does not matter much.
Petr K Lol this is an extremely ignorant comment. Do you have any idea the type of power and infrastructure that would be required, to charge a plane full of batteries? I can’t believe you compare that to a laptop that can be charged from a standard wall outlet. Electric cars take roughly 8-12 hours to fill up.
@@michaelesposito2629 Because you don't understand my argument obviously. I was also talking about car battery (think EV). That is 3 orders of magnitude larger than your laptop battery ... yet it takes roughly hour to charge. Same as your laptop. Think about it for a while. Of course - battery for something like 737 would be again order of magnitude larger (or more) and similarly it would need order of magnitude (or two) larger charger, than some Tesla Supercharger. But that can be done. Limiting factor is again speed at which you can charge single cell.
Petr K I’m done. I can’t have such a complicated discussion with someone clearly so ignorant. And stop using “orders of magnitude” as If you understand what that means
@@michaelesposito2629 Ahh... I see. you are an expert troll. You win then. Maybe just out of curiosity (if you are only making a real great impression of a troll) - if largest notebook batteries have 100Wh (ie MB Pro) and largest battery in Tesla (so far) has 100kWh, how many orders of magnitude is that ?
I believe hydrogen fuel cells would work for the aviation industry not lithium batteries. Compressed hydrogen has an energy density of 142 MJ/kg. Lithium ion batteries have an energy density of 0.6 MJ/kg. Looking forward to your next video
Niza Siwale that would be a much more mass efficient fuel source and would be much easier to implement the infrastructure to support, as most forklifts at the airports already operate on hydrogen fuel cells
Jawad H no, hydrogen bombs operate on a combination of fission and fusion to cause a very powerful release of energy. Hydrogen fuel cells operate by electrolysis (combing hydrogen and oxygen to create energy and water
you dont even need fuel cells, you can use turbines with liquid hydrogen, the efficiency of the turbine increase because you may have higher temperature difference and use lighter materials that would be cooled by the lh2. On fuel cells you can also use super conductor electric motors cooled by the lh2. Liquid h2 is so light that you will need way less fuel to do the same trip, so the volume density is not an issue, even less if you design the aircraft with hydrogen in mind.
One other thing that makes fossil fuels ideal for aircraft is that when you burn them, that weight is gone. Especially in the case of the airliner, as they burn off fuel, the plane get lighter so they can move to a higher altitude where they can fly faster and more efficiently. Batteries don't get lighter as the power drains so they don't afford that luxury. Along those same lines, a pilot typically only has the plane filled with enough fuel to get where the flight is going plus a required margin of safety. This allows the airplane to fly more efficiently or allows them to use weight that would have been allocated for fuel for cargo instead. It would be much harder, if possible at all, to remove batteries for shorter flights that don't require the maximum range of the aircraft so you're always taking off with a maximum fuel load whether you need it or not. These issues, combined with the power density problem, make a battery operated airplane less than ideal for anything but recreational flight.
CrashDavi - that would potentially solve one problem but add a few new ones: 1. What would you do with the dropped batteries? Replace them every flight? That's expensive. It'd be prohibitively expensive to recover them and ship them back, especially on trans-Atlantic flights. 2. The mechanism would add weight, cost, complexity and failure points to the aircraft, none of which are good. 3. Batteries don't drain sequentially, but rather in parallel so you can't drop them until they're all dead anyway. And setting it up with several banks that run sequentially would add cost, weight and more failure points to the aircraft. 4. Parts falling off the plane mid-flight might panic passengers (or at least make them uneasy).
EchoSX - Very true! Most aircraft are not designed to handle landing at gross weight. Another potential issue is that as a battery drains, it loses power (the voltage drops) so the power available to use at the end of a charge is less than at the beginning. Generally this wouldn't be an issue for an aircraft... until you have to abort a landing and do a go-around - then you want every bit of power that thing has to offer. Jet Fuel/100LL/mogas gives the same power down to the last drop :-)
Great video! I actually have worked a few summer internships in the eflight field, and this is exactly the big concern at stake for the industry. Although I think it is misleading to say that doubling the mass increases power requirement x8 (5:20). If you are comparing the doubled mass case to the original, then the 2 before the M in the equation cancels, leaving only a four-fold difference.
I think the comparison is not completely fair, as it's putting current electric systems in vehicles using 50+ year old design, technology, and materials. It would be like installing a Tesla Model S drivetrain in a 1957 Chevy Bel Air. An electrified '57 Chevy will not get the same mileage and performance as a new car designed to maximize the electric drivetrain.
Do these formulas take into consideration that the plane gets lighter for the more fuel that it burns? And that a plane cannot land when it is full of fuel, it can’t bear the extra weight at landing. Batteries will remain a constant weight throughout the flight, so this is a massive factor when compared to burning fuel.
Planes are engineered to account for this. If someone developes an Electric Plane (when the Battery Technology is ready) it would be very stuipid for the Engineers to not account for this.. in fact i would delegate them to design Plastic Spoons instead and hope for the best if they didnt account for this..
You’re right, though probably counting to support that extra weight will add even more weight to the planes structure, at least with current technology . It’s exciting to see what innovation will bring.
hans vadder Not gonna lie but thats pretty true. Ask a white girl whats a hdmi or usb cable. They wont know shit. They only know the cable that charges their phone so they can snapchat and instagram. There are some exceptions but its most likely super small.
Also, males use TH-cam more than females. And I don't think it is sad, the world needs all sorts. If everyone was more interested in things than people, who would be nurses?
It's simple, contrary to what fat feminists want, women are not interested in engineering. Period. And I always find it ironic (and moronic) how all those art and gender studies graduates complain about the lack of female engineers and CEOs. Then fucking study it.
I think the implication is millennials are smarter but the demographic data might be flawed because boomers, AKA the generation that put men on the moon, are less gullible and less likely to share every detail of their personal information or maybe they're tired of technology stuff having spent their careers fighting the cold war and building the infrastructure we all enjoy today. OK boomer, thanks for actually doing something.
i don't quite appreciate the part about the rockets in the beginning, since even if batteries had the same power density as fuel, since rockets are mostly fuel in weight , there is the problem that batteries don't loose their weight when depleting, not to mention the issue about creating an engine that can put out enough thrust. thumbs up for the for the rest of the video tho ;)
But rockets don't require fossil fuels anyway. It's not like we don't have an alternative, it's just a choice the designers of the falcon 9 made to have it use kerosene. The perfectly clean alternative of liquid hydrogen exists.
that because Kerosene is works better for low earth orbit rockets, also it's denser than liquid hydrogen (which is also why the saturn V had a kerosene first stage and hydrogen in it's upper stages) but for their new Big Falcon Rocket which is meant for interplanetary missions, spaceX will be using methane rocket engines, cuz it can be produced artifically from Co2 and water, which means, it could be made on mars for example
I didn't say there was no reason for them making that decision, simply that they did. Ultimately, it's the cheapest, best fit. What I am saying is that rockets, specifically, already have a viable clean fuel option. It costs more because of all the complex systems involved but it's not like an entirely electric rocket would be superior in cost and all around performance to kerosene either, the point is that it would be clean but that already exists. Of course, electrical propulsion systems already exist for spacecraft but right now they don't produce remotely enough thrust to launch.
Person Oisels - What you said about rockets is true for planes too. We can synthesize kerosene and burn them in planes, it's just prohibitively expensive.
+Q0ET9U I didn't say anything abot synthesizing kerosene. Also many rockets have used liquid hydrogen, it's not "prohibitively expensive" (mostly because rockets are expensive anyway), just more expensive.
To use simpler formulas, you can look at figures for fuel consumption for an airplane. A 747 consumes around 4 liters of kerosene per second traveled. One liter of kerosene contains 37 MJ of energy. A 7 hour trip uses 4 * 3600 * 7 * 37 = 3,700,000 MJ of energy. The Tesla Model S batteries are state of the art, and have an energy density of 700 MJ/ton. Replacing the kerosene with such batteries will give a battery weight of: 3,700,000 / 700 = 5,300 tons. Compare with the maximum take-off weight of a 747 which is around 400 tons, not even in the same ballpark.
Yeah this video had a lot of pretty irrelevant math when all you need to do is compare specific energy - about 43 MJ/kg avg for aviation fuel, and about 1 MJ/kg for current state of the art production LiCoO2 batteries (Li-S promises doubling energy density to just under 2 MJ/kg). One thing worth noting, a Cessna 172 uses a 160-180HP (120-134kW) w/ a 117kg dry weight, while a 120kw electric motor will only be around 25kg. The Lycoming O-360 engine on the Cessna burns about 30L/hr, so a 4 hour flight would be 120L of fuel, about 96kg (0.8kg/L) - that's about 4.1 GJ of energy to produce @ 120kW, 1.7MJ of thrust (sounds about the right efficiency for an ICE) and a final motor+fuel specific energy of 19.4 MJ/kg. An electric motor should be 85%+ efficient, and you probably can realistically only discharge to around 80% before falling below voltage, so you'd need to carry around about 2.5GJ of battery for the same flight. The motor weight is a rounding error for doing our calculations, basically, you'd need 2500kg of LiCoO2 batteries, so about 12X the weight. HFC is probably an option should be about 5-10X performance of battery systems, although that's largely dependent on how small the energy subsystem is (I haven't looked close enough at what the state of the art is). There are also some mid-term battery improvements, like solid-state that would probably get you there as well. Heck, if you could get lithium-air working, you could probably beat out jet fuel performance...
Nice video thank you. @5:19 the mass component of this equation is only squared (not doubled), doubling the mass increases power requirement 4 fold not 8.
Just found this comment after scrolling for miles down the comment section thinking 'why hasn't anyone picked up on this!'. I think Real Engineering has got mixed up as the factor of 2 has just been introduced into the equation. The factor of two however can just be assimilated into a constant, k, and power will still be proportional to the mass^2. So doubling the mass, increases the power 4 fold.
Volume of a cylinder is the area of its base times its height so: A x H . Divide it by time and you have A x H/t. H/t is distance/time which is just velocity, so we get: A x v(flight). Mass of the air is simply its density multiplied by its volume: M(air)=ρ x V, while mass flow rate is simply mass divided by time, so: Ṁ(air)=ρ x V/t and we already know what Volume / time is: A x v(flight), so we get: Ṁ(air)=ρ x A x v(flight). Also, for the lift formula, you can use impulse to explain it: Impulse (Force x time) is change in momentum (momentum is Mass x Velocity, and change in momentum is the Mass x Change in Velocity, so: M∆v). F x t (impulse) = M∆v (change in momentum) and if we divide both sides by t, we get: F=M∆v/t, and M/t is just mass flow rate, F(lift) = Ṁ(air) x ∆v(z).
it's basically a bunch of basic physics equations and a lot of algebraic substitutions... but to really get a handle on the whole thing, you need to know each physics equation well when he throws it in, so at the speed he was going, you're really better off just letting him finish instead of trying to catch it as he goes. if you really want to know everything bit by bit, slow the video down or pause it and wikipedia each new equation he brings up. it will probably take 5-15mins per equation if you're completely new to them all, and that one equation would thus take about an hour or so to fully understand. not impossible, but it goes to show why hard sciences can't be rushed.
I've heard that the "Moore's Law" of batteries is that they improve in energy density by ~5% per year. If that trend continues, it'll be decades until they get close to the energy density of fossil fuels. They're already at or close to the point where they're good enough for cars, but it may be quite a while before they're good enough for airliners. However, there's _a lot_ of research going into battery technology right now. A big breakthrough could change everything.
Lithium-air batteries are a major leap in battery technology and will require further improvements but they are very close to the energy density of petroleum-based fuels.
@@sweetpotatoe19 Ew imperial units... lol jokes but on a more serious note so is it like Energy (Nm) / Weight (N) to give m? And then what would the example like you gave go like? Like say if it's 1000m in the air and your energy height is 2000m then you say 50% of the airplane's energy is altitude? And does that mean if your energy height is less than your altitude your plane should be falling?
@@sweetpotatoe19 oo this reminds me of Bernoulli's equation where the kinetic energy term is V^2/2g. So ok you can find your speed in that example but how do you find your energy height? I thought in the first example you said like the kinetic energy divided by the weight gives your energy height and so you can determine how much energy is used for speed. But in this case you're using energy height to find speed so it's the other way around? How would you find energy height in this case since your kinetic energy term 0.5mv^2 already includes velocity?
Given that energy density is increasing, it would be interesting to see what happens to flight times as we get to 500Wh/kg (which is where we're at now) to 700Wh/k (I believe they're getting around 740Wh/kg in the lab), etc.
Not anymore. Every A320neo variant has a range adequate to fly New York to London. The reason they are not used is because that is a very frequently traveled route from two very busy airports, and it could be somewhat counter productive to use an airport slot using a comparatively smaller plane when they could fill A330 and B777 to capacity.
Yes, given two criteria are met: 1. Your battery banks are of such a volt/ampere output and of such capacity that the weight of your power supply does not exceed the maximum load of your frame or the maximum lift of your wings. 2. That the electrical motors you use (propeller this type) output a significant enough amount of thrust that the drag coefficient of your lifting body is outweighed and a significant enough amount of lift is generated that you can gain stable flight. The alternative to a simple propeller is essentially a fuel less jet turbine, where you have an air intake that compresses air when moving at a certain speed so that the pressure inside is significant enough for effective heating of the air using coils so that the thrust of the engine is great enough to again, overcome the drag coefficient of your lifting body and provide enough lift for stable flight. The main problem with this is that you have to be moving at a specific speed threshold before air compression becomes practical, thus you essentially have to use turbines only up until this point, unless you can design a heating system effective enough that it can use uncompressed air. In conclusion: This is a great engineering challenge as currently even the most weight efficient high capacity batteries are most likely not capable of providing the sustained power output necessary, beyond that an entirely new set of engines have to be developed, as almost every single plane has relied on one of four key engine types with some variations and improvements. However there are several alternatives to batteries: Solar planes, however surface area vs thrust has to be massive because solar panels output a tiny amount of energy in comparison to say, jet fuel or batteries, which means that you'll be lucky to reach 100mph because your drag coefficient is going to be bigger than this post. The other option is electrical nuclear, but that runs into the problem of radiation shielding, and essentially you'd need a lead brick as a plane, or you'd need some sci fi radiation energy shield. Beyond that good luck finding room for your generators or all that water and piping (if you're using BWR). The only real way this could possibly be practical right now is to use a conventional jet engine for takeoff and landing and use electrical engines for cruising using the electrical jet I described above, even so you'd have very limited range unless you utilized perhaps non combusting exothermic chemical reactions to heat the inner skin of a jet engine, which runs into a whole other range of problems and may be less ecologically sound than even just regular jets. All in all, practical some day soon? Yes given that energy storage technology continues to advance. Practical today? No.
Energy density of batteries isn't the only problem when it comes to big, fast planes. Let's say we have batteries with 40 times better energy density. How you gonna make that battery propell the plane? You can't use turbine jet engines because they need hot pressurized gasses to work. For now the only way is electric motor and propellers which would work fine but you can't fly too fast, not as fast as jets can. Unless there is some kind of "alien" engine we won't see electric big planes at all. That's the problem with electricity, without something spinning or wibrating or getting hot at the end of the wires you can't do anything with it. With fossil fuel all you need is a lighter. But because we are running out we need real engineers to solve the problem;).
A 70 ton max take off weight large propeller plane is already doing 400 mph cruising speed . It does however use four 4,637 shp (3,458 kW) engines . en.wikipedia.org/wiki/Lockheed_Martin_C-130J_Super_Hercules#Specifications_(C-130J) I am guessing the propellers do some 1000 to 1200 rpm so an electric motor capable of doing that is not a problem . Electric motors are capable of more rpms . In theory its possible to design airliners which will do cruising speeds of 500 mph. Its just that the energy density of batteries is not there. Fossil fuel extraction technology is also progressing. Technology will progress for discovering and extracting fossil fuel . We will not run out of fossils for a few more centuries . I refuse to believe we will run out of fossil fuels anytime soon .
Running out of fossil fuels was never the question though, was it? It's not particularly helpful to have another 200 years of reserves (or whatever) if the entire damn planet is under water by then, you know? :|
You can run a turbine that propels air backwards. I can't be arsed to look up the source, but the largest portion of a plane's thrust does NOT come from the combustion part.
You didn't mention how by using liquid fuel the aircraft becomes lighter as it burns more fuel. Also, there are other systems which consume electricity in the plane, radios, heaters, etc. If we assume a bleedless aircraft like 787 then we have to take into account the power required to run the compressors for pressurisation. That would reduce the overall flight time even more
But we also have to factoring the reduction in mass due to electric engines being lighter for the same power, and the reduction in mass due to not requiring fuel pumps and backup fuel pumps. And the fact that we are, at worst, swapping out the fuel tanks for a battery bank, so we need to substract the weight of the fuel system, not just add the weight of the batteries. Ideally, the entire aircraft frame would be completely redesigned around the battery system, as the batteries don't need as much structural reinforcement as a fuel tank. Electric is still not efficient enough to be viable, but it's not actually as bad the calculations in the video suggest.
GabDubé twenty percent of the wet weight is fuel. That's all you have. And considering that aircraft tanks are integral tanks, as in they are made up of empty areas of the structure, and wings, (as in they aren't separate tanks) your argument falls flat on it's face. Also electric motors the size of which would be needed, would be pretty goddamn heavy, not that far off of a jet engine(which by the way, do not weigh as much as you think they do). Also the fact that as an aircraft flies, it gets lighter, and the fact that all large aircraft Max takeoff weight i.e. full fuel load, exceeds their max landing weight, you actually have less than twenty percent to play with, more like 15 percent.
GabDubé also fuel pumps weigh like twenty pounds at most(the really big ones) and there are only one for each engine. There is no such thing as backup fuel pumps. You can cross feed off of one pump, that is the backup. There may be boost pumps in the tanks, but those are also fairly small. Source: I work on the fucking things.
GabDubé sorry but a lot of stuff was not included in the calculations, as i said there are other systems on the aircraft critical to its operation which require electricity to operate, we also we haven't talked about the flight control systems which require hydraulic pumps to be operated. Fuel tanks aren't some seperate compartment like in a automobile, it is part of the structure of the aircraft.
Ok, but isn't it true that you can make an aircraft that is insanely heavy and it can still fly so long as you dont try to take it more than like 35m above the surface? I seem to recall the nazis having one such vessel (they crashed it tho so yea)
@@ConstantChaos1 yeah its called ground effect. and it was the soviets. they had a bunch of ground effect vehicles. they're rusting away in storage now :( What Helljumper256 is saying is that after a plane has left ground effect, it is no longer pushing air down
Nice video ! I have a question: do you remember hidrogen cars ? It would be great if you could make a video about the possibility of having hidrogen powered planes - this would really be a possibility but not enough companies are looking into it. What do you think about this?
Where did you get number for the weight of an empty Airbus A380 at 6:56 you mentioned that the battery mass would be 260,000 kg which is 4 times the mass of the empty air plane which would be 62,500 kg. I dont see a Airbus with this small a mass someone correct me if im wrong though.
I thought that Flift is equal to the weight of the plane and Fdrag is equal to the thrust provided by the engine. This would mean that the engines generate enough thrust that the plane could fly straight up like a rocket. I must be missing something. I'm at 5:05 in the video and will stop here until I figure out what this apparent nonsense is all about.
I think "Flift = Fdrag" is a typo. It should read "Plift = Pdrag" i.e Power required for lift = Power required to overcome drag. This interpretation is consistent with the next formula after the one at 5:05 (which is at 5:08) where the author multiplies the right side of the equation by 2.
Bad assumptions built on bad assumptions. For instance, the formula completely ignores Lift/Drag (planes don't pay the energy cost for Lift, they pay for Drag- which is much smaller) ratio for most of the video, or how that changes with cruising speed... Electric planes can achieve longer range by flying at slower speeds, or with higher mass-fraction dedicated to batteries (not an unreasonable solution since batteries are much denser in terms of mass per unit volume than Kerosene...)
Yeah, the math section is wrong almost from the start because of this. The work equation isn't simply force times distance. It is force IN THE DIRECTION OF TRAVEL times distance. Vertical and horizontal forces on the aircraft don't contribute to work, because the aircraft has zero velocity in those directions. Think of a blimp: it isn't doing work by floating, even though it has large forces from lift and gravity. If the blimp turns on an engine and starts pushing forward, then it is doing work, but the vertical forces still don't enter into the amount of work being done. One could argue that even though the aircraft has zero vertical velocity, the air being pushed down does not, so it still makes sense to use this equation. But the motion of the air around the aircraft is complicated and the equations here go too far off base to be worthwhile. Beyond assumptions that might be wrong regarding swept area, one place where this analysis goes wrong is at 4:39. We're solving for Delta V sub z (downward velocity imparted to swept air) based on an assumption of how much mass of air the aircraft is passing through per unit time, which depends on the swept area around the aircraft. If that mass of air is huge (long wings) then that velocity is smaller. If that mass is tiny (short wings) then the velocity is higher. So the velocity imparted depends on the mass of the air. Fine! But in the lower equation, that velocity is multiplied by the mass of the aircraft. But that's not the mass being accelerated! In fact, we already know Delta V sub z for the aircraft: zero. If we're trying to derive power requirements for moving air, the power equation has to be in terms of mass of the air, not the aircraft. By 4:44 the equations are really messed up. Because we treated the mass of the aircraft as being pushed by Delta V sub z instead of the mass of air from which we just derived it, we have this squared mass of aircraft term in the numerator for the power equation. That term shouldn't exist. All the analysis after this point doesn't make sense. Another way to say this: The application of Power = Force * Velocity is wrong, because Force was derived from the aircraft and velocity was derived from the air. Power = Force * Velocity was derived from Power = (Force * Distance) / Time. This equation is correct when the Force is being Applied over some Distance in the direction of travel. But the Force from the aircraft is not being applied over a vertical distance. There is no vertical component to the aircraft's movement.
" (planes don't pay the energy cost for Lift, they pay for Drag- which is much smaller) " That's simply wrong. On an aeroplane at its most efficient cruising speed about 50% of the power is used in providing lift and about half in overcoming in drag. It is possible to design planes with much larger wing areas which fly relatively slowly to reduce the proportion of power spent on the lift element, but they aren't very conducive to acceptable journey times. Providing lift requires power. The lift in free air is precisely equal to the rate of change in the momentum of air deflected downwards. It's straight Newtonian mechanics the lift must equal weight in level flight. The larger the mass of air that can be accelerated downwards with the least increase in velocity, the better as the power required goes to the square of the increase in downward air velocity, whilst the momentum change (force/lift) varies only linearly. Larger masses of air moved downwards, means bigger wings and flying slowly as drag increases. The idea that the power costs of lift is somehow insignificant is just wrong.
@@rychan0 Another one that gets it wrong. The video is talking about the downward deflection of air that provides the lift, not the downward direction of the aeroplane. The lift is the rate of change of momentum of the air downwards, and that takes power. As the only source of energy in an aeroplane in level flight is from the engines, then that's where the energy to accelerate air mass downwards comes from. There is no law that says just because an aeroplane has thrust from an engine in a horizontal direction doesn't mean that some of that isn't used in accelerating a mass of air downwards. That's exactly how planes fly, by a combination of Benoulli's principle and, more importantly, the angle of attack of the wing. If you have trouble with this idea, think of a hovering helicopter. It's not moving anywhere, yet it is using immense amounts of power. Where is that power going? It's going into accelerating a lot of air downwards (on top of the thermodynamic losses of course).
8:46 Bio-fuel! (Maybe synthetic fuel, but not to hopeful about that.) In the form of butane, and some cutting-edge fuel cells to power electric distributed propfans.
I think you forget to take into account the fact that electric planes would be able to fly higher due as the electric engines would not require oxygen to burn, leading to a lower air resistance. This would however require a faster, more aggressive ascent, but if we were to put solar cells on the planes, the altitude and exposure to the sun would most likely make up for it? Idk, I’d need to run numbers to be sure but it’s a theory
What are we gonna do with the solar cells? That's gonna add more weight than the efficiency it would increase, plus this plane won't lose weight while flying, so the range is fixed
The ability of an aircraft to fly higher is directly dependent on the amount of lift the wings can produce, which is directly affected by the shape of the wing as well as the weight of the craft. More factors to account for: Even the most advanced and efficient batteries are extremely heavy and bulky when you scale them up to the size needed to be the sole power source for a commercial aircraft, more weight reduces maximum altitude and reduces efficiency. Flying at higher altitudes also means reinforcing the structure of the fuselage and rest of the craft in order to withstand the pressurization load necessary to keep the crew and passengers alive. All I'm trying to say is that it is such a more complicated question to answer than just saying "Yes they could fly higher."
Why not distribute the passengers of a A320 into multiple Cessnas, then station aircraft carriers 2hours appart in the ocean, where they can land and swap their batteries?
The obvious answer is that Cessnas are two-seaters, so you could only sit one passenger in each, the other being a pilot. (Or two if you assume there's no pilot and your cessna is an autopiloted drone). So to convert an A320 sitting 180 passengers into cessnas, you'd need 180 cessnas. Surprisingly, 180 cessnas are cheaper than an A320, so that may be a viable solution, financially.
They don't need to be flying at the same time. That way you can also have them take off as soon as the passengers are ready to embark, giving more flexibility to your schedule. The obvious drawback of course is that it would be hell to manage a fleet that size, and maintenance costs would skyrocket.
I'm a bit concerned that pressure difference around the wings were never mentioned. Maybe it's included in that downward air stream that was mentioned around 4:20 but I felt like it's excluded. Very interesting video none the less, thanks for sharing!
Another issue with using li ion cells is that it is extremely dangerous especially when in that big of a capacity. They could use those new ceramic batteries though!
“Hey guys, don’t worry, we’ll give you a formula sheet on the exam”
The formula sheet:
Momentum = mass • velocity
The Exam:
If we were to take a Cessna plane, and convert it’s fuel source to battery power, what would be it’s ideal flight time?
Casey Glann oh no
Idk. Approx 45 minutes to an hour 20. lmao. Add solar panels to wings and that time would increase to approx 2-4 hours. But they might have to remove bathrooms from the plane to compensate for the weight.
@@dylandepetro4187 what
@@williamhosking2913 it was a joke. lol.
@@dylandepetro4187 what's a bathroom?
me: *falls asleep during physics*
me: *wakes up*
teacher: 5:05
me: *concerned*
Haha so true
Story my life
XD
2 ez 4 me m8
Story of my life
JIck Jalck its not hard
Really liking the new thumbnails, they look so clean and nice.
Reddie Animates No captions = dislike
+Ramkumar Suresh N V What do you mean?
He didn't use the unnecessary arrow that so many thumbnails love to have. :0
Reddie Animates Yes, he so intellectually honest in his thumbnails. That is why he deserves respect.
Whaaaaaahh? *_Ramkumar Suresh N V_* how is that a coherent or even understandable sentence?
Now i know what my dog feels when im speaking to it
Psyched for the next episode! Always been curious how hydrogen works as fuel.
TierZoo very well. Because their combustion with oxigen makes water and heat
Unless you're using fuel cells which do not combust the H2 with O2 to produce electricity (and releasing water as a byproduct) .
Using a hydrogen fuel cell. It works sort of like a battery but uses hydrogen and oxygen instead of two metals.
It is not an internal combustion engine.
Shockwave Shockwave what you said. Heat energy powers the engine, water comes out the back pipe.
why did you not research it on your own, why are you waiting for someone to hand it to you served on a silver plate?
We're sorry but you have reached your limit for equations used. Please try again later.
Jody Kemper he used more equations than we use in university
The equations were simple.
The real ones are partial diff equations.
Take calculus it’s a lot of this stuff, not hard, it is basically just plugging stuff in. Looks scary though
Different - that's a pretty sad university right there!
This is the kind of math I wish I could do, just plug is equations that I seem to know off the top of my head and get the needed answer like its a trip in the park. Too bad it isn't like this at all Dx
What about if we use Duracell?
Eh?
You never thought about that, did you?
energizer is better!
NASA: You're hired
This “real engineering guy” is just talking baby level physics, it’s not that hard but he made the equation signs so complicated, try to make him look smart, Eh~
Maybe we should all just ride on giant pink jumping battery powered mountain climbimg rabbits?
yea
2:57 "What is delta V"
Ksp players: Whomst has summoned the almighty one.
Hahahaha so true, I already knew what it meant when I started A-level physics because I played so much KSP
Lol
I absolutely love your videos.
They never feel rushed but rather polished.
Yes, I read many books to learn the concepts. However, nothing will link these concepts to real life like the way you do my friend.
Invested in Brilliant after seeing you recommend it with heart countless times and it is worth every cent.
That's nice of you to say, because I literally only finished this video 30 minutes before it was published. All my videos are rushed!
Real Engineering if it is well done, that doesn't matter. I'm sure you check your videos over multiple times before you upload it.
Real Engineering I really enjoy watching your videos they have taught me a lot about engineering and physics they are always teaching me something new, have you ever thought of making a video about the mechanics of nuclear reactors?
The video are good, and I do appreciate them, just that sponsorship kinda make me very uncomfortable watching this, it feels like being brainwashed, pateron kinda feels better, also, What's with the similarity to whendover productions
jack Chang wendover and him are friends.
1:37 Talks about regular planes.
**Shows a Concorde.**
Im making one of those
There's a joke about Belgians I particularly like (I'm Belgian btw)
The Belgians invented an electric car. Costs 1 million dollars though. 100k for the car, the rest for the extention cord.
Why specifically Belgians?
Matthew Goodman Dutch people always joke about Belgiums.
The belgians are the target for jokes from all their neighbors. It's all in good fun.
Europe is a strange continent. In several recent video games the Russians are the bad guys. Why? If you make the French the bad guys, they won't buy your game. The Russians don't mind, they will buy your game anyway.
In the same way Belgians don't mind being surreal idiots... Well, because basically we are Lol
Lolol
Did you account for the efficiency differences between fossil fuel powered engines and electric engines or the fact that liquid fuels are used during flight which lowers the planes mass as it flies on over time vs. electric powered aircraft which don't lighten their load with duration?
Yeah, liquid fuel just makes a ton of sense for airplanes. They should just master and find ways to convert electricity to liquid fuels efficiently. That, or find ways to make solar energy or wind energy directly convert the power to create a liquid or solid field. I know they kind of already do this for some rocket fuels etc, but I haven't seen it in a way that would work for planes.
The main problem is the sustainability. It doesn't *need* to be electricity. Quite frankly, I hope we can get some sort of biological solution to the problem. I heard that some scientists were able to turn genetically modified switchgrass into a jet fuel precursor, which would be really neat if it could be scaled.
Oh, they lighten their load. E=MC^2. M=E/C^2 - what's the differential of energy? You might be able to lighten by as many as a few nanograms!
* electric motors
Hold on a moment... as the conventional aircraft burns fuel, it also becomes lighter. The electric aircraft's weight would remain the same. The performance of the conventional aircraft would increase over time as the amount of fuel on board burns and exhausted through the engines.
yup. I always would wonder as a little tiny child, "Does it burn more fuel to have a full tank, rather than a quarter tank... hm?" lol
+34486 This is exactly why usually planes don't fly with a full tank. They carry enough fuel + contingencies.
That's true. But turbines have a vastly different efficiency curve at take-off (max power) and cruise (around 60% power). Turbines are burning inefficiently while cruising, sometimes their carbon footprint actually rises at altitude.
Hybrid-electric, battery/fuel cell electric do not have that issue.
+Ohnonomomono The reduction of fuel efficiency with increased altitude is due to air density change, as described in the video. It applies to all aircrafts. But yes, different types of jet engines have different ideal altitude (ie. air density) and air speed.
Maximum efficiency is at full power, and low outside temperature. Calculations here are perhaps true, but definitely not used in aerospace engineering in terms of performance. Check out the Breguet Range Equation. web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node98.html
i love this. it's like all that math from school, but actually relevant to solve interesting problems.
True
And that's why I'm studying engineering.
All math leads to solving real problems... Can't do calculus without algebra. Can't do physics without calculus. Can't do linear algebra without calculus. Can't do differential equations without calculus. Etc
@@mr.caswell2388 mechanical and electronic engineer rules
@@fieldmarshal7298 What about Aeronautical Engineering?
U lost me at triangle
Triangle is change, also known as delta
He lost me at airplane
The triangle is change in
You must be the 2.9%
YRS MUSIC whats funny is that honestly this video is a pretty basic intro to much deeper aviation mathematics
Me 7 minutes into this video: sooooooo is that a no?
Basically he’s saying battery energy density isn’t dense enough currently to be a solution unless someone improves battery density enough to become an answer.
@@DylanBegazo that's good if that's the only problem because as it stands everybody is already trying to fix it. Tesla, Panasonic, Samsung, and several others are already racing.
@@user-pq9gy3fq1q Forgot three of the biggest battery players, CATL, LG Chem, and BYD.
Starts watching. Sees explanation about batteries being 40x heavier than kerosine. Makes sense, I'm happy I know this now. But starting at 2:12 I felt more and more stupid and I should go back to my coloring book :(
Kevin Bauwens taking AP physics in highschool wasn’t completely useless...
just kidding. Idk what he’s talking about still. Sos.
I looked like I knew what he was saying but deep down I was like fuuuuuk....
8:55
Wait ,how old are you ? Im 14 and i understood everything but im a bit of a geek. Anyway its probably because you didnt do physiks in a while.
Don't worry it is all fluff to lengthen the video. The main point here is that batteries will not work for long range planes.
However, I think the electric planes will be the future. The thing this video is missing is hydrogen, hydrogen fuel cell systems. Power density of this just dwarfs any kind of fossil fuel.
If we go overboard with renewable energy, we could be storing them as hydrogen.
Start a new channel called “Simple Engineering” for us plebs
PLEASE! lol
Actually though, we want simple engineering.
This video is very simple
ask jundroo for that
BlueON YT not for everyone
8:56 This guy seems to have MUCH bigger problems than equations. Lol
@ninjarawr21 wtf
ninjarawr21 shut the fuck up cronge normie reeeeee
@@sushiboxchris ha
@ninjarawr21 well, you seemed to have missed the comedy in the original comment...
What could be bigger than equations?
Me a 24 y/o with a high school education after being held back as a freshman: ah yes of course that's how you figure Delta v
Np, lets do nuclear airplanes instead.
It's funny because the US actually tried to do that. The main issue though was thrust to weight, as a nuclear reactor is wayyyyy to heavy for a plane, and thr idea was to basically just heat air to create thrust.
@@tfowlis6659 And nuclear reactor are that heavy simply because of all the shielding need to block those pesky neutron!
@@Randomguy-wd5lw Actually Russia and the united states both put reactors in the back of planes to see if they could carry the load. The problem just became pointless when you could nuke your enemy with ICBMs much cheaper and easier.
@@vampov I think you didn't finish your comment.
Us had a plane with a reaktor onboard but it did not power the plane. The Russian actually had a working plane that was powered but the nuclear reactor. The main problem though it was puking out contaminated air and it had so little protection. It did not even protect its own crew..
5:20 “Doubling the mass will increase our power requirements 8-fold.” This is incorrect. The factor of 2 in the power equation is present in the calculation for both the lighter and the heavier plane, meaning it can be factored out. Doubling the mass increases our power requirements by a factor of 4.
Yeah that made me go 🤔🤔🤔🤔
Russell Schwartz yea I definitely caught that too I was like hmm 🤔 soon as I heard that
Yeah I don't get how he can think that. "it's not only squared but also doubled" wtf?
Glad not to listen with all his fluff to lengthen the video. He shot himself on the foot with all the equations.
However, I think the electric planes will be the future. The thing this video is missing is hydrogen, hydrogen fuel cell systems. Power density of this just dwarfs any kind of fossil fuel.
If we go overboard with renewable energy, we could be storing them as hydrogen.
@@zodiacfml yeah, but sadly lose most of the energy in the process of making it and using it.
Very informative. Another interesting point is that airplanes get lighter in flight as they proceed, whereas battery mass doesn't change. This results in airplanes departing and arriving with the same mass. On conventional aircraft that would be an overweight landing. Battery powered aircraft would need reinforced landing gear and therefore have added mass
Marc Wenger Maybe the plane could drop some of the batteries 2/3rds of the way out on a paraglider or something ;)
To do something like the 747 to 787 electric would require a massive rethinking of the whole aircraft so it’s not totally unreasonable to imagine something crazy.
I do think that long haul airplanes will need some kind of fuel for a long time though. But maybe we could gain more efficiency with some kind of hybrid design. If we can cut fuel consumption enough we could use biofuels.
Marc Wenger Plus longer runways will be necessary to prevent runway overruns due to weight increase at landing
@@auspiciouslywild The logistics of dropping the batteries seems risky and difficult.
@@auspiciouslywild We've been using hybrid design for a long time now. The current 787 Dreamliner is the closest thing to an "Electric airplane" we've ever built on the scale of a commercial aircraft, as well as the fact that it is the most fuel efficient large airliner ever created. Compared to the Airbus A380, which is its main competitor, the 787 was shown to be about 60% more fuel efficient.
And crashes 60% more than Airbus 😂
@@Cynsham
4:46 alright boys, we gotta start launching as much of earth into space as possible so we can reduce the strength of gravity. Who's with me?
I'm in!!! 😁😁😁😂😂😂
Another problem is that the batteries become dead weight while burning fuel the airplane becomes lighter and it can fly further and higher.
97.1% Male Viewers, there is more sausage on this channel than on a german bbq party
we're talking about engineering, not about washing dishes
In Aachen*
Please explain in layman’s terms about the quantity of sausage on this channel.
LMAOOO
actually i'm a woman and this made me laugh
@@SandraWantsCoke 1:52
1:52 97.1% male and 2.9% female... wow.
Keep in mind that, statistically speaking, more than 2.9% of males portray themselves as female online. So, that gives us a negative value for female representation here. Which is about right. But I'm sure someone will stop me and tell me that umpteen million women really are interested in engineering, it's just that this channel only allows males. Or something about privilege.
Yeah the creator of this channel must make a better effort to attract women! Instead of concentrating on creating great content. [sarcasm]
w0mbles
And how many women portray themselves as men?
Anthony Gomez low average IQ for women
proves we are nerds
The calculations could be simplified by working out how much thrust an aircraft needs to take off, climb, and maintain level flight, then work out how much power is required to generate that amount of thrust, then multiply it by how long that level thrust will be used, then add those energy requirements together to calculate the total energy needed for a given flight
one thing you forgot:
for prop aircraft, fuel usage is proportional to power
for jet aircraft, fuel usage is proportional to thrust.
that is why, when determining maximum range, you look at the power graph for prop aircraft and the thrust graph for jet aircraft.
Why is that?
@@jonibeYT jet aircraft turn fuel directly into thrust by spitting the burned fuel out the back.
Prop aircraft turn fuel into thrust indirectly by spinning a propeller. This makes them less efficient when the air is thin, or when the plane is already going fast.
flightacademy.info/aviation-power-curves
@@josiahmartin329 Jets dont spit out the fuel but they heat up air which expands and that way gets pushed out of the back. Maybe the point is that in thinner air the jet can heat up the tinier amount of air more which results in the same thrust while the propeller is limited by its tip speed and the sound barrier because if that isnt the case the propeller can just spin alot faster because of the reduced drag
Jets require fuel, the theory here revolves around electric propellers.
This channel is the only one I choose to be notified about
Same here. Well, CGP Grey too, but he takes fucking forever to post anything.
Well done sir
"I've got an idea for electric jet" - Elon Musk to Tony Stark in Iron Man 2...
We have only to wait. He will handle that!! ;)
🔴 It cannot be a "Jet" if it's electric, by the very definition of the term, "Jet"- engines burn fuel.
it would have to be a 'Ducted-fan' configuration.........
@@joshhayl7459 Jet has many definitions, and while on its own the word is colloquially used to refer to a aircraft powered by "jet engine"; there are words that are used with it to denote a more specific meaning, for example "jet propulsion", "jet stream", "jet engine" - so adding a qualifier like "electric jet" is sensible and understandable to a lot of people.
According to biologists, some cephalopods utilize jet propulsion to quickly move around in the water. Don't try to tell me they burn fuel too ;)
@Jan Stankiewicz ,
🔵 Perhaps you could provide me with a link to an "Electric jet aircraft", as I am unfamiliar with anything that fulfills that technical-description.
@@joshhayl7459 I thought they were only a concept, but I found a video of a working prototype just by googling. It's called Lilium Jet. Link below. In return, would you be so kind to provide me with a link to a definition of jet that specifies it needs to burn fuel? th-cam.com/video/mjAJWrraTKs/w-d-xo.html
Hi, good video but I noted two small mistakes. 1) (delta x) /t = v, not delta v. Delta v represents the acceleration, not the speed. 2) Doubling the mass, will not increase the power demand by 8. It will increase it by 4, even though there is a 2 factor in the equation. Let's say for example that P1 is the power of the light aircraft and P2 is the power of the heavy aircraft and that M1 is the weight of the leight aircraft and M2 is the weight of the heavy aircraft. If the heavy aircraft has twice the mass of the light aircraft, it means that M2=2*M1. If you plug 2*M1 in the equation to find P2 and then you divide P2 by P1. P2/P1=4 (the factor 2 cancels out).
Wrong! Vector-v of the standard delta within the given range of p - xrt120 over vex factor 2, is the precise analysis of any range given at par levels of accepstance, with all guidelines of sub-par equasions at exact values of 10, but not exceeding 12, but between values of particle norms of anything in the middle of whats not core value at relative transitioning. Depending upon what is, might be or could be, given everything it is and should be.
@@XtremeXbox lol trolling hard
@@jammingboss Sorry if my knowledge was above your pay grade.
Doubling the mass does not increase the energy 8x. Since no matter the mass of the plane the mass square is always doubled (for e.x. 1^2=1 1x2=2 2^2=4 4x2=8 8/2=4. The energy increases 4x.
I think 8-fold is an idiom.
Mark Schultz shut the fuck up
I was thinking if you have a cube, and increase all sides length with x2it will be 8 times volume
In reality increasing the mass seems to have little effect. A 747-SP weighs four times as much as a737 MAX, but only has three times the engine power. They really screwed the pooch on this clip.
yall some effing scientists
better than my science class
NS RIDER of course what are u talking about?
NS RIDER but still boring.
Good video but using an "x" to denote multiplication next to an "x" that's a variable killed at least three cute puppies.
I was like: "Since when did work done become a cross product?"
Another thing worth pointing out is that the amount/weight of the kerosene decreases as it is being used while a battery pack weighs the same wether it's at 100% or 5 %
lol, just put windmills on the plane bro not that hard
LUETIN but... Damn it.
Beside those windmills will cause so much drag that it will consume more energy than the windmills will deliver. Simple physics.
LUETIN No, a mix of Red Bull and paddos works much better.
We kinda already do that. Look up an APU for passenger jets.
buddy cant take a joke
There also is a turnaround problem as well. Fossil It is very quick to refuel and easy to drop fuel to lower the weight of the plane in emergency situations. both of these problems would need solved as well.
Could have standardized battery packs, swap them out at the airport for them to charge and put a charged one in, take right back off. Like propane tanks. That could theoretically be even faster than refueling.
Might be a bit dangerous, li ion battery if mishandled can catch fire, jet a in comparison has to be atomised in order to catch fire.
Harish Rajan Everything with that level of energy concentration can ignite when mishandled. Even jet fuel.
GabDubé yes, i didn't say jet a is not volatile, but no one is in a hurry to swap it around, imagine if u want to swap the batteries they have to be removed by a forklift of something, which increases the danger of the batteries being mishandled
5:20 "Doubling the mass will increase our power requirements 8 fold". I might be missing something, but how does this come out of the equation you just showed? I realize there is a 2x at the front, but this shouldn't change what happens when you double M_plane. For example, assuming the value of all other variables is 1 (to make this easy) you are simply left with 2*M^2. If you plug in 1 for M you get 2, if you plug in 2 for M you get 8. This is a 4 fold increase.
Came here to say the same, Friedrich Nietzsche, I think you are absolutely right, the 2 will not lead to an 8fold increase, it's only the square that counts!
Great video though.
Wrh does 8 fold mean
-James R
Not even then, the 2 inside the brackets would become a 4 outside of the brackets and the same issue would remain.
Square cube law
Actually, the reason is due to the need to also increase the size of the wing to accommodate the lift required for the increased mass, or to increase the speed with the same wing area. And if you fly faster, you are using the energy at a faster rate over a given distance. The conclusion stands, but it is embedded in the equations.
"She's totally giving you hints!"
Her hints: 3:19
im Very confused and dont know what they mean
I don't think that was right at 5:16. Multiplying the mass by 2 will cause the power to multiply by 4, not 8.
@Bob Saget Say you had M=2, you would get 2*(2)^2 = 2*4 = 8
And then M=4 would give 2*(4)^2 = 2*16 = 32
Double M, and you quadruple the result, because it is proportional to M^2 and multiplying by any constant will have to be done in both calculations. 2M^2 is proportional to M^2, and 43875M^2 is proportional to M^2. Any constants involved don't change that, because they remain constant.
@@katzen3314 🤔😂
weight is shared equally on the wing, hence it will result in 4 instead of 8, 8/2
But he just says double the power not double the mass. This is the difference between 2*m^2 and (2m)^2. And the former is what he puts into the formula so I don't get why he would say times 8 when that doesn't line up with the actual equation given.
Plus at 5:06 he directly says "double our power requirement," and not "double our mass and multiple by 2 after." And before someone says something about the mass of the fuel, is doubling fuel weigh really going to double the plane's mass?
Actually, the reason is due to the need to also increase the size of the wing to accommodate the lift required for the increased mass, or to increase the speed with the same wing area. And if you fly faster, you are using the energy at a faster rate over a given distance. The conclusion stands, but it is embedded in the equations.
One HUGE drawback of such a low power density energy, is the landing weight since you don't loose significantly weight over time. On traditional airliners, you can't land safely with a full fuel tank. You can't either dump the batteries in case of an emergency.
PS: Love your vids !
nowadays modern airliners can land with full fuel tank, I learn this from @Mentour Pilot . He says fuel is really expensive to an Airlines, they really want to keep it if possible.
The problem is more that when you have an emergency, you really want to dump fuel and return, to set yourself up for an as easy landing as possible. Would you go for a severely overweight landing with inoperative slats, flaps, spoilers or thrust reversers? No, you dump fuel.
xponen_ not according to the tcds and far regulations they can't. All aircraft whose takeoff weight exceeds maximum landing weight are required to have jettison systems, (which all modern airliners have) because of the simple fact that they can NOT land with a full fuel load.
It’s a good point but just a bit of inside info. On aircraft where Max landing Max is less than Max take off, you have to achieve that mass to land with in normal operations. However, you absolutely can land over weight, as long as the landing performance allows it will be perfectly safe. An instance would be if you are required to land immediately, such as smoke on board. Commercial Aircraft are tested to land at Max take off weight for safety reasons. For instance a serious fire after take off that requires an immediate landing. Normally post any over weight landing, an inspection is required by local engineering on stress prone areas. It’s actually about preventing long term stress from repeated over weight landings rather than damage from a single landing. Hope that provides a bit of colouring in.
airindiana and runway overruns. Landing g rolls are longer than takeoff rolls
5:20
"Doubling the mass will increase our power requirements eightfold."
Wouldn't that only be the case if M is cubed?
NO, because its being multiplied by 2 as well
2squared multiply by 2 is 8
But then doubling the mass only increases power by 4 since the 2 is in both initial and doubled mass scenarios
Yeah, they made a mistake there. The 2x is a constant factor that would be in the before and after values, just like the gravitational constant, etc. Should have said fourfold.
Yeah, the explanation is clearly wrong. Examples:
If we reduce the mass by square root of 2, squiring mass would be half of original. Now we add the 2x (that is wrong) and the power didn't change.
Or if we don't change the mass and square them mass (1^2) and after that multiply by 2, we have 2x more power consumption without changing any variables.
0:49 I think Boeing are mainly in a battle to make a plane that doesn't f*cking crash.
*Ah fuck. Not again*
-Boeing
You are over 50,000 times more probable to get into a car crash than into an air crash.
@@JoshyDMCOfficial Very true, more ppl die in car crashes happened than plane crashes. The plane crashes just look more tragic
Edit: it's actually more tragic
@@saocxdc210 with a car crash, there is always that hope that you'd live and people don't usually see it coming, or they do, but still maintaining hope.
With a plane crash, well it's hard to have any hope when a typical plane crash kills everyone. A plane crash though damn!! Must be fucking terrifying. Fuck, it happens in areas that cars have no business being. Nightmarish areas that you wouldn't hell dream of journeying with a car. My lord yo!
@@grassh0pper I agree with you on that point. That's one of the biggest weakness in aviation, no one can save any plane airborne
I'm just watching this in the hope that one day there will be a drug that allows me to understand what he just said.
Until NZT48 is made I'd suggest large quantities of adderall and wasting at least one semester in a engineering program at a good school
I dropped out at the first semester but I kinda got it (full disclosure tho newton is my great×8 uncle tho)
I smoked a very large bowl before watching this and I'm stoned out of my mind but trust me when I tell you this still got me like ._.
Ketamine, you must take. Run over minorities in your 2001 Honda Civic, you must. Recognise the legitimacy of the State of Israel, you will not. Make sense, the equations will.
@@drone_better7757 10/10
There is a 'drug' for this. 7th grade physics.
Mass is squared and doubled so starts at 2m^2. doubling mass gives 2x(2m)^2 = 8m^2.
8m^2/2m^2 =4 rather than 8
Reuben Mason yeah I was like wtf are you talking about when he said that
This is such a grave mistake, he should reupload a new corrected video.
ue=
Glad not to listen with all his fluff to lengthen the video. He shot himself on the foot with all the equations.
However, I think the electric planes will be the future. The thing this video is missing is hydrogen, hydrogen fuel cell systems. Power density of this just dwarfs any kind of fossil fuel.
If we go overboard with renewable energy, we could be storing them as hydrogen.
I understood it to mean doubling the already doubled mass would result in a factor of 8 times the Original M^2.
That's how I read it...but I don't know if that's what he intended or he really made an error. Great info though.
Batteries also don't get lighter as they are used up, which also factors into the range.
Well, technically, they get a few micrograms lighter...
That is certainly amusing.
111danish111 how? When fuel is used, it's gone, which means the plane is lighter, meaning g it can fly higher and faster which increases the range. Just like your car. Remove weight=better fuel economy
Totally correct I meant Hanif Shakiba's comment was amusing.
You can eject the spent batteries silly
In your formula, you forget that lift has to do with the airplanes wing area, not just the wing length. On top of that, is has quite a lot to do with the airfoil shape, so lift can actually be altered in many ways just by changing the airfoil cross-section, the sweep the wing has (in order to reduce the vortices on the wingtips - also done with winglets and sharklets), and by delaying the separation of airflow before the trailing edge. It has to do with angle of attack and whatnot. The issue with wings is, they're made sturdier by having the fuel stored in them (in layman's terms), so eliminating any storage of fuel in them can actually be detrimental to lift, due to the fact you'd have to choose a shape that is more durable, but is much less aerodynamic.
Also, when you use the word "leading edge" in an aviation video, it tends to confuse people, as it has a whole other meaning in the aviation field.
Wrong. At 2:30 the work is the dot product of displacement and the force. For an horizontal flight the work of the lifting force is ZERO.
en.wikipedia.org/wiki/Work_(physics)#Mathematical_calculation
The only forces that need work is the drag. The wing are not perfect and generate a certain % of drag proportional to the lift. It in the range of 1/15th to 1/20th.
en.wikipedia.org/wiki/Lift-to-drag_ratio
So somehow some of the drag is proportional to weight but all your calculations are a bit strange...
Of course this is not all the drag. There's some because of frictions, the aerodynamics of the fuselage...
you are right
Yup, very strange equations indeed. My eyes began to fill with blood when he divided DeltaX by just t, not DeltaT (it's very ugly way to write derivative!), than he named velocity he got with DeltaV, which is totally wrong, there should be just V. But the final straw was to consider lift, not drag, you're right.
PolarBearVodka007 That's the whole problem this video tries to solve... I would do it another way. Imagine you have a working plane and add extra weight. You have to increase lift. The best way is to increase the size of the wings. Of course this also increases the weight. Also some structure is needed. At the end of the day you have to add even more wings... Conclusion: it's not really linear. A point that was not taken into consideration is the volume. For the same energy you need a lot of space.
Electric planes are possible (see solar impulse) but at the cost of huge planes and very low speeds. (One of the trick is to use solar power to increase the energy available and also increase of altitude to store energy during day and going down slowly during night)
PolarBearVodka007 and BTW yes even considering his method it's x4 not 8 when doubling the weight.
Another point is that the equation has 1/L^2 factor but if you increase weight a lot you have to use bigger wings or you just can't take off and cruise at decent speeds even with flaps.
To simplify things let's just say the lift doubling needs a doubling in wings area so an increase of sqrt (2) of L. So doubling mass will x4 the numerator and x2 the denomitor. At the end you just get x2 power with his equation...
Engineering at it's best.....2:04
Cessna with wheels skidding on water
Freewheeling on water it's a common maneuver but don't hit the brakes you'll dig in and flip
@daAnder71 Thank you so I didn't have to say it.
@@josephpayne113 so what to use instead of it's?!
@@shriharir6450 Its.
@@josephpayne113 ahh.. Ohh well.. Hmm.. Okay!!
Well I thought (it's=its).. Anyways.. Tnx tho.. :)
Can batteries melt steel beams?
Depends on their energy output.
Yes. th-cam.com/video/bABCvucGATc/w-d-xo.html
If they are on fire than most likely yes.
If that's the story the government needs to explain some buildings collapsing, then yes.
everything is possible if you believe in it
There is another issue with Batteries, specifically with Lithium-Ion: Capacity decreases with use. Every time you recharge the battery, just a little bit more of the battery's capacity is lost, and thus the next charge won't last as long for the same amount of draw. It might not be noticeable at first, but if your Cesna is barely making it's trip on a single charge, eventually the plane will lose all power in the middle of landing, and after that it starts dying mid-flight. And if you somehow not died at this point, the battery won't hold a charge at all. We've all seen this with out smart phones.
So you would only get the maximum range out of a battery-powered plane so many times before that battery needs to be replaced. And while battery recycling is a thing (and is why, for cars and boats at least, there's an additional fee for buying a battery if you aren't bringing in a dead one), there is still an inevitable waste that will happen.
The weight of a plane held by kerosine gets lower with the flight time, while not true for battery powered
Which is important as the plane is expected to have shed that weight at landing time as it makes landing easier and safer with battery powered planes you would not only have to overcome the energy density problem but also the problem of having to do redesigns to fit with the fact the plane will be the same weight when it lands as when it took off.
Maybe a good transitional technology would be to install a reforming unit aboard existing aircraft to make hydrogen from gasoline, which would then power a fuel cell. Then, as hydrogen storage tech got better you could just use the fuel cell. A small battery bank would be used for takeoff power.
Just drop the dead batteries.........BIG BRAIN
Great video, but in my opinion two important points were missed.
1. Jet engines are really bad in efficiency when compared with electric engines. Jet engines using kerosene can reach up to 60% of the fuel beeing converted in kinetic energy. As for electric engines that number is quite close to 100%, so in the “back of the envelope calculation” u could remove about 35% of that kerosene and still have a good safety margin.
2) Fuel mass in airplanes varies with time, wich is quite good for them, and doesn’t in electric airplanes.
Love the channel!
1:53 97.1% of us are males
I noticed, wtf
what a shocker...
Who would've expected women to not be interested in useful things!
Bit depressing, isn't it? Each to their own, but we've clearly got a long way to go as a society. There's an awful lot of wasted potential being untapped.
I don't mind women being or not being interested in engineering, but people claiming we're the same are just wrong, clearly women have other interests.
One important factor you also forgot: Charge time. What would the charge time be for 200,000kg worth of batteries? "Welcome to London, we'll see you next week when the plane has recharged" 😂
Same as your notebook battery, car battery or any other battery (roughly one hour assuming good enough power source). Whether you charge single cell or thousand cells in parallel does not matter much.
Petr K Lol this is an extremely ignorant comment. Do you have any idea the type of power and infrastructure that would be required, to charge a plane full of batteries? I can’t believe you compare that to a laptop that can be charged from a standard wall outlet. Electric cars take roughly 8-12 hours to fill up.
@@michaelesposito2629 Because you don't understand my argument obviously. I was also talking about car battery (think EV). That is 3 orders of magnitude larger than your laptop battery ... yet it takes roughly hour to charge. Same as your laptop. Think about it for a while.
Of course - battery for something like 737 would be again order of magnitude larger (or more) and similarly it would need order of magnitude (or two) larger charger, than some Tesla Supercharger. But that can be done. Limiting factor is again speed at which you can charge single cell.
Petr K I’m done. I can’t have such a complicated discussion with someone clearly so ignorant. And stop using “orders of magnitude” as If you understand what that means
@@michaelesposito2629 Ahh... I see. you are an expert troll. You win then.
Maybe just out of curiosity (if you are only making a real great impression of a troll) - if largest notebook batteries have 100Wh (ie MB Pro) and largest battery in Tesla (so far) has 100kWh, how many orders of magnitude is that ?
I believe hydrogen fuel cells would work for the aviation industry not lithium batteries. Compressed hydrogen has an energy density of 142 MJ/kg.
Lithium ion batteries have an energy density of 0.6 MJ/kg. Looking forward to your next video
I agree with you
Niza Siwale that would be a much more mass efficient fuel source and would be much easier to implement the infrastructure to support, as most forklifts at the airports already operate on hydrogen fuel cells
Jawad H no, hydrogen bombs operate on a combination of fission and fusion to cause a very powerful release of energy. Hydrogen fuel cells operate by electrolysis (combing hydrogen and oxygen to create energy and water
Hydrogen is dangerous, specially for flying, if not ask the Hindenburg....
you dont even need fuel cells, you can use turbines with liquid hydrogen, the efficiency of the turbine increase because you may have higher temperature difference and use lighter materials that would be cooled by the lh2.
On fuel cells you can also use super conductor electric motors cooled by the lh2.
Liquid h2 is so light that you will need way less fuel to do the same trip, so the volume density is not an issue, even less if you design the aircraft with hydrogen in mind.
One other thing that makes fossil fuels ideal for aircraft is that when you burn them, that weight is gone. Especially in the case of the airliner, as they burn off fuel, the plane get lighter so they can move to a higher altitude where they can fly faster and more efficiently. Batteries don't get lighter as the power drains so they don't afford that luxury.
Along those same lines, a pilot typically only has the plane filled with enough fuel to get where the flight is going plus a required margin of safety. This allows the airplane to fly more efficiently or allows them to use weight that would have been allocated for fuel for cargo instead. It would be much harder, if possible at all, to remove batteries for shorter flights that don't require the maximum range of the aircraft so you're always taking off with a maximum fuel load whether you need it or not.
These issues, combined with the power density problem, make a battery operated airplane less than ideal for anything but recreational flight.
Was going to post this, but you got there first.
You could loose the used bateries by parachute I guess.
There is also the planes takeoff and landing weights. A long haul flight cannot land safely without either burning its fuel or purging it.
CrashDavi - that would potentially solve one problem but add a few new ones:
1. What would you do with the dropped batteries? Replace them every flight? That's expensive. It'd be prohibitively expensive to recover them and ship them back, especially on trans-Atlantic flights.
2. The mechanism would add weight, cost, complexity and failure points to the aircraft, none of which are good.
3. Batteries don't drain sequentially, but rather in parallel so you can't drop them until they're all dead anyway. And setting it up with several banks that run sequentially would add cost, weight and more failure points to the aircraft.
4. Parts falling off the plane mid-flight might panic passengers (or at least make them uneasy).
EchoSX - Very true! Most aircraft are not designed to handle landing at gross weight. Another potential issue is that as a battery drains, it loses power (the voltage drops) so the power available to use at the end of a charge is less than at the beginning. Generally this wouldn't be an issue for an aircraft... until you have to abort a landing and do a go-around - then you want every bit of power that thing has to offer. Jet Fuel/100LL/mogas gives the same power down to the last drop :-)
Minor nitpick: Strictly speaking, “Energy Density” is energy per unit volume, not per unit mass. “Specific Energy” is energy per unit mass.
Great video! I actually have worked a few summer internships in the eflight field, and this is exactly the big concern at stake for the industry.
Although I think it is misleading to say that doubling the mass increases power requirement x8 (5:20). If you are comparing the doubled mass case to the original, then the 2 before the M in the equation cancels, leaving only a four-fold difference.
2^2=4. also at 5:05 "Flift=Fdrag" should be "Plift=Pdrag".
I think the comparison is not completely fair, as it's putting current electric systems in vehicles using 50+ year old design, technology, and materials. It would be like installing a Tesla Model S drivetrain in a 1957 Chevy Bel Air. An electrified '57 Chevy will not get the same mileage and performance as a new car designed to maximize the electric drivetrain.
Do these formulas take into consideration that the plane gets lighter for the more fuel that it burns?
And that a plane cannot land when it is full of fuel, it can’t bear the extra weight at landing.
Batteries will remain a constant weight throughout the flight, so this is a massive factor when compared to burning fuel.
Planes are engineered to account for this. If someone developes an Electric Plane (when the Battery Technology is ready) it would be very stuipid for the Engineers to not account for this.. in fact i would delegate them to design Plastic Spoons instead and hope for the best if they didnt account for this..
UniTrader THANKYOU.
You’re right, though probably counting to support that extra weight will add even more weight to the planes structure, at least with current technology . It’s exciting to see what innovation will bring.
1:52 Only 2.9% female.
That is because most Females don't give a fuck how something works, as long as it works...really sad.
hans vadder Not gonna lie but thats pretty true. Ask a white girl whats a hdmi or usb cable. They wont know shit. They only know the cable that charges their phone so they can snapchat and instagram. There are some exceptions but its most likely super small.
Also, males use TH-cam more than females.
And I don't think it is sad, the world needs all sorts. If everyone was more interested in things than people, who would be nurses?
It's simple, contrary to what fat feminists want, women are not interested in engineering. Period. And I always find it ironic (and moronic) how all those art and gender studies graduates complain about the lack of female engineers and CEOs. Then fucking study it.
97.1% male
2.9% female(male)
“Looking at the demographic breakdown of this channel we can go a little deeper” 😂🤣😂🤣🤣😂
Did you notice over 97% of viewers are Male? And liberals say that the number of female engineers is sexist. They're just not interested.
hahaa! For sure.
It was such a stupid thing to say- a mind that dismisses 30+ people is pretty shallow. (if that's how he meant it)
XD
I think the implication is millennials are smarter but the demographic data might be flawed because boomers, AKA the generation that put men on the moon, are less gullible and less likely to share every detail of their personal information or maybe they're tired of technology stuff having spent their careers fighting the cold war and building the infrastructure we all enjoy today. OK boomer, thanks for actually doing something.
i don't quite appreciate the part about the rockets in the beginning, since even if batteries had the same power density as fuel, since rockets are mostly fuel in weight , there is the problem that batteries don't loose their weight when depleting, not to mention the issue about creating an engine that can put out enough thrust. thumbs up for the for the rest of the video tho ;)
But rockets don't require fossil fuels anyway. It's not like we don't have an alternative, it's just a choice the designers of the falcon 9 made to have it use kerosene. The perfectly clean alternative of liquid hydrogen exists.
that because Kerosene is works better for low earth orbit rockets, also it's denser than liquid hydrogen (which is also why the saturn V had a kerosene first stage and hydrogen in it's upper stages) but for their new Big Falcon Rocket which is meant for interplanetary missions, spaceX will be using methane rocket engines, cuz it can be produced artifically from Co2 and water, which means, it could be made on mars for example
I didn't say there was no reason for them making that decision, simply that they did. Ultimately, it's the cheapest, best fit. What I am saying is that rockets, specifically, already have a viable clean fuel option. It costs more because of all the complex systems involved but it's not like an entirely electric rocket would be superior in cost and all around performance to kerosene either, the point is that it would be clean but that already exists.
Of course, electrical propulsion systems already exist for spacecraft but right now they don't produce remotely enough thrust to launch.
Person Oisels - What you said about rockets is true for planes too. We can synthesize kerosene and burn them in planes, it's just prohibitively expensive.
+Q0ET9U I didn't say anything abot synthesizing kerosene. Also many rockets have used liquid hydrogen, it's not "prohibitively expensive" (mostly because rockets are expensive anyway), just more expensive.
To use simpler formulas, you can look at figures for fuel consumption for an airplane. A 747 consumes around 4 liters of kerosene per second traveled. One liter of kerosene contains 37 MJ of energy. A 7 hour trip uses 4 * 3600 * 7 * 37 = 3,700,000 MJ of energy. The Tesla Model S batteries are state of the art, and have an energy density of 700 MJ/ton. Replacing the kerosene with such batteries will give a battery weight of: 3,700,000 / 700 = 5,300 tons. Compare with the maximum take-off weight of a 747 which is around 400 tons, not even in the same ballpark.
Björn Morén
Man you made it soo much easier.
Yeah this video had a lot of pretty irrelevant math when all you need to do is compare specific energy - about 43 MJ/kg avg for aviation fuel, and about 1 MJ/kg for current state of the art production LiCoO2 batteries (Li-S promises doubling energy density to just under 2 MJ/kg). One thing worth noting, a Cessna 172 uses a 160-180HP (120-134kW) w/ a 117kg dry weight, while a 120kw electric motor will only be around 25kg.
The Lycoming O-360 engine on the Cessna burns about 30L/hr, so a 4 hour flight would be 120L of fuel, about 96kg (0.8kg/L) - that's about 4.1 GJ of energy to produce @ 120kW, 1.7MJ of thrust (sounds about the right efficiency for an ICE) and a final motor+fuel specific energy of 19.4 MJ/kg.
An electric motor should be 85%+ efficient, and you probably can realistically only discharge to around 80% before falling below voltage, so you'd need to carry around about 2.5GJ of battery for the same flight. The motor weight is a rounding error for doing our calculations, basically, you'd need 2500kg of LiCoO2 batteries, so about 12X the weight.
HFC is probably an option should be about 5-10X performance of battery systems, although that's largely dependent on how small the energy subsystem is (I haven't looked close enough at what the state of the art is). There are also some mid-term battery improvements, like solid-state that would probably get you there as well. Heck, if you could get lithium-air working, you could probably beat out jet fuel performance...
lhl, good of you to also include fuel/motor efficiency in there.
What is HFC? Sounds interesting.
Björn Morén Hydrogen Fuel Cell, what I assume the end of the video is talking about (liquid Hydrogen really isn’t a realistic for planes).
Nice video thank you.
@5:19 the mass component of this equation is only squared (not doubled), doubling the mass increases power requirement 4 fold not 8.
Just found this comment after scrolling for miles down the comment section thinking 'why hasn't anyone picked up on this!'. I think Real Engineering has got mixed up as the factor of 2 has just been introduced into the equation. The factor of two however can just be assimilated into a constant, k, and power will still be proportional to the mass^2. So doubling the mass, increases the power 4 fold.
I am 13 and your vidios are the only way I can understand these complex equations keep up the good work! Thank you!
@3:45 Who else is completly lost?
He tried to explain it in a very complicated way
just make notes during the video then it makes sense
Yeah....im lost....but i want to understand :(
Volume of a cylinder is the area of its base times its height so: A x H . Divide it by time and you have A x H/t. H/t is distance/time which is just velocity, so we get: A x v(flight).
Mass of the air is simply its density multiplied by its volume: M(air)=ρ x V, while mass flow rate is simply mass divided by time, so: Ṁ(air)=ρ x V/t and we already know what Volume / time is: A x v(flight), so we get:
Ṁ(air)=ρ x A x v(flight).
Also, for the lift formula, you can use impulse to explain it: Impulse (Force x time) is change in momentum (momentum is Mass x Velocity, and change in momentum is the Mass x Change in Velocity, so: M∆v).
F x t (impulse) = M∆v (change in momentum) and if we divide both sides by t, we get: F=M∆v/t, and M/t is just mass flow rate, F(lift) = Ṁ(air) x ∆v(z).
it's basically a bunch of basic physics equations and a lot of algebraic substitutions... but to really get a handle on the whole thing, you need to know each physics equation well when he throws it in, so at the speed he was going, you're really better off just letting him finish instead of trying to catch it as he goes.
if you really want to know everything bit by bit, slow the video down or pause it and wikipedia each new equation he brings up. it will probably take 5-15mins per equation if you're completely new to them all, and that one equation would thus take about an hour or so to fully understand.
not impossible, but it goes to show why hard sciences can't be rushed.
I've heard that the "Moore's Law" of batteries is that they improve in energy density by ~5% per year. If that trend continues, it'll be decades until they get close to the energy density of fossil fuels. They're already at or close to the point where they're good enough for cars, but it may be quite a while before they're good enough for airliners. However, there's _a lot_ of research going into battery technology right now. A big breakthrough could change everything.
www.greentechmedia.com/articles/read/this-startup-is-building-an-electric-airplane#gs.reO6Plg
you have a bugged show more show less maybe your editing
Lithium-air batteries are a major leap in battery technology and will require further improvements but they are very close to the energy density of petroleum-based fuels.
Diego C. That’s not how trends work. The fundamental limit of lithium battery specific energy is way lower than that.
2:45 You really should not write "delta-v" for velocity. It should just be "v" - the velocity.
I think is delta-v 'cause it's a change of velocity
@@sweetpotatoe19 Interesting! In coastal engineering energy density is referred to as energy per metres squared for a wave.
@@sweetpotatoe19 Ew imperial units... lol jokes but on a more serious note so is it like Energy (Nm) / Weight (N) to give m? And then what would the example like you gave go like? Like say if it's 1000m in the air and your energy height is 2000m then you say 50% of the airplane's energy is altitude? And does that mean if your energy height is less than your altitude your plane should be falling?
@@sweetpotatoe19 oo this reminds me of Bernoulli's equation where the kinetic energy term is V^2/2g. So ok you can find your speed in that example but how do you find your energy height? I thought in the first example you said like the kinetic energy divided by the weight gives your energy height and so you can determine how much energy is used for speed. But in this case you're using energy height to find speed so it's the other way around? How would you find energy height in this case since your kinetic energy term 0.5mv^2 already includes velocity?
this, kinda pissed me off he kept the delta. basically made it acceleration at a single point instead of velocity
Given that energy density is increasing, it would be interesting to see what happens to flight times as we get to 500Wh/kg (which is where we're at now) to 700Wh/k (I believe they're getting around 740Wh/kg in the lab), etc.
JFK to London is a very unusual route for an a320
He's not entirely wrong the A318 flies that route and it's considered part of the A320 family
he was just giving an example for the maximum range.
I said unusual, does 1 route/service sound usual to you?
What does JFK mean? Just fu*king kidding?
Not anymore. Every A320neo variant has a range adequate to fly New York to London. The reason they are not used is because that is a very frequently traveled route from two very busy airports, and it could be somewhat counter productive to use an airport slot using a comparatively smaller plane when they could fill A330 and B777 to capacity.
My brain is broken
Not to worry all he is saying is that you will not see an electric airliner for another 15 to 20 years.
You will see a lot of cool stuff in your life . I am middle aged so not so much for me !!
Thanks for reminding me why I failed physics in high school. 👀
Yes, given two criteria are met:
1. Your battery banks are of such a volt/ampere output and of such capacity that the weight of your power supply does not exceed the maximum load of your frame or the maximum lift of your wings.
2. That the electrical motors you use (propeller this type) output a significant enough amount of thrust that the drag coefficient of your lifting body is outweighed and a significant enough amount of lift is generated that you can gain stable flight. The alternative to a simple propeller is essentially a fuel less jet turbine, where you have an air intake that compresses air when moving at a certain speed so that the pressure inside is significant enough for effective heating of the air using coils so that the thrust of the engine is great enough to again, overcome the drag coefficient of your lifting body and provide enough lift for stable flight. The main problem with this is that you have to be moving at a specific speed threshold before air compression becomes practical, thus you essentially have to use turbines only up until this point, unless you can design a heating system effective enough that it can use uncompressed air.
In conclusion: This is a great engineering challenge as currently even the most weight efficient high capacity batteries are most likely not capable of providing the sustained power output necessary, beyond that an entirely new set of engines have to be developed, as almost every single plane has relied on one of four key engine types with some variations and improvements.
However there are several alternatives to batteries: Solar planes, however surface area vs thrust has to be massive because solar panels output a tiny amount of energy in comparison to say, jet fuel or batteries, which means that you'll be lucky to reach 100mph because your drag coefficient is going to be bigger than this post.
The other option is electrical nuclear, but that runs into the problem of radiation shielding, and essentially you'd need a lead brick as a plane, or you'd need some sci fi radiation energy shield. Beyond that good luck finding room for your generators or all that water and piping (if you're using BWR).
The only real way this could possibly be practical right now is to use a conventional jet engine for takeoff and landing and use electrical engines for cruising using the electrical jet I described above, even so you'd have very limited range unless you utilized perhaps non combusting exothermic chemical reactions to heat the inner skin of a jet engine, which runs into a whole other range of problems and may be less ecologically sound than even just regular jets.
All in all, practical some day soon? Yes given that energy storage technology continues to advance. Practical today? No.
Just walk lol
But the ocean
Walking across the Atlantic is something I loved to do until I took an arrow to the knee.
Just swim lol
First: why da meme
Second: but it takes so long
Yeah!
Energy density of batteries isn't the only problem when it comes to big, fast planes. Let's say we have batteries with 40 times better energy density. How you gonna make that battery propell the plane? You can't use turbine jet engines because they need hot pressurized gasses to work. For now the only way is electric motor and propellers which would work fine but you can't fly too fast, not as fast as jets can. Unless there is some kind of "alien" engine we won't see electric big planes at all. That's the problem with electricity, without something spinning or wibrating or getting hot at the end of the wires you can't do anything with it. With fossil fuel all you need is a lighter. But because we are running out we need real engineers to solve the problem;).
Siemens and others are testing this already. Do a google search.
A 70 ton max take off weight large propeller plane is already doing 400 mph cruising speed . It does however use four 4,637 shp (3,458 kW) engines .
en.wikipedia.org/wiki/Lockheed_Martin_C-130J_Super_Hercules#Specifications_(C-130J)
I am guessing the propellers do some 1000 to 1200 rpm so an electric motor capable of doing that is not a problem . Electric motors are capable of more rpms . In theory its possible to design airliners which will do cruising speeds of 500 mph. Its just that the energy density of batteries is not there.
Fossil fuel extraction technology is also progressing. Technology will progress for discovering and extracting fossil fuel . We will not run out of fossils for a few more centuries . I refuse to believe we will run out of fossil fuels anytime soon .
Running out of fossil fuels was never the question though, was it? It's not particularly helpful to have another 200 years of reserves (or whatever) if the entire damn planet is under water by then, you know? :|
You can run a turbine that propels air backwards. I can't be arsed to look up the source, but the largest portion of a plane's thrust does NOT come from the combustion part.
Kasseenzettel not going to happen. The ice caps were totally gone for a couple years and nothing happened. Just saying.
You didn't mention how by using liquid fuel the aircraft becomes lighter as it burns more fuel. Also, there are other systems which consume electricity in the plane, radios, heaters, etc. If we assume a bleedless aircraft like 787 then we have to take into account the power required to run the compressors for pressurisation. That would reduce the overall flight time even more
Harish Rajan Hear Hear! 😄
But we also have to factoring the reduction in mass due to electric engines being lighter for the same power, and the reduction in mass due to not requiring fuel pumps and backup fuel pumps. And the fact that we are, at worst, swapping out the fuel tanks for a battery bank, so we need to substract the weight of the fuel system, not just add the weight of the batteries. Ideally, the entire aircraft frame would be completely redesigned around the battery system, as the batteries don't need as much structural reinforcement as a fuel tank.
Electric is still not efficient enough to be viable, but it's not actually as bad the calculations in the video suggest.
GabDubé twenty percent of the wet weight is fuel. That's all you have. And considering that aircraft tanks are integral tanks, as in they are made up of empty areas of the structure, and wings, (as in they aren't separate tanks) your argument falls flat on it's face. Also electric motors the size of which would be needed, would be pretty goddamn heavy, not that far off of a jet engine(which by the way, do not weigh as much as you think they do). Also the fact that as an aircraft flies, it gets lighter, and the fact that all large aircraft Max takeoff weight i.e. full fuel load, exceeds their max landing weight, you actually have less than twenty percent to play with, more like 15 percent.
GabDubé also fuel pumps weigh like twenty pounds at most(the really big ones) and there are only one for each engine. There is no such thing as backup fuel pumps. You can cross feed off of one pump, that is the backup. There may be boost pumps in the tanks, but those are also fairly small. Source: I work on the fucking things.
GabDubé sorry but a lot of stuff was not included in the calculations, as i said there are other systems on the aircraft critical to its operation which require electricity to operate, we also we haven't talked about the flight control systems which require hydraulic pumps to be operated. Fuel tanks aren't some seperate compartment like in a automobile, it is part of the structure of the aircraft.
Depending on how long the electrical wire is, yes.
Im an aerospace engineer and an aircraft mechanic and planes dont fly by anything as arcane as pushing air down
I heard they are powered by money.
@@wuffos more like the souls of passangers dragged off southwest and the pain and suffering of those that fly on spirit
Actually, they do. Ever heard of newtons third law?
Ok, but isn't it true that you can make an aircraft that is insanely heavy and it can still fly so long as you dont try to take it more than like 35m above the surface? I seem to recall the nazis having one such vessel (they crashed it tho so yea)
@@ConstantChaos1 yeah its called ground effect. and it was the soviets. they had a bunch of ground effect vehicles. they're rusting away in storage now :( What Helljumper256 is saying is that after a plane has left ground effect, it is no longer pushing air down
Nice video ! I have a question: do you remember hidrogen cars ? It would be great if you could make a video about the possibility of having hidrogen powered planes - this would really be a possibility but not enough companies are looking into it. What do you think about this?
Hidrogen? Hydrogen potato potato
can you please not use the bottom of the screen so much?
some of us use captions and they cover the video
Where did you get number for the weight of an empty Airbus A380 at 6:56 you mentioned that the battery mass would be 260,000 kg which is 4 times the mass of the empty air plane which would be 62,500 kg. I dont see a Airbus with this small a mass someone correct me if im wrong though.
It's A320 not A380
Great video, however I question the approximation that Flift = Fdrag, since most commercial planes (A320, B747) have a lift to drag ratio of about 15
I thought that Flift is equal to the weight of the plane and Fdrag is equal to the thrust provided by the engine. This would mean that the engines generate enough thrust that the plane could fly straight up like a rocket. I must be missing something. I'm at 5:05 in the video and will stop here until I figure out what this apparent nonsense is all about.
I think "Flift = Fdrag" is a typo. It should read "Plift = Pdrag" i.e Power required for lift = Power required to overcome drag. This interpretation is consistent with the next formula after the one at 5:05 (which is at 5:08) where the author multiplies the right side of the equation by 2.
Bad assumptions built on bad assumptions. For instance, the formula completely ignores Lift/Drag (planes don't pay the energy cost for Lift, they pay for Drag- which is much smaller) ratio for most of the video, or how that changes with cruising speed...
Electric planes can achieve longer range by flying at slower speeds, or with higher mass-fraction dedicated to batteries (not an unreasonable solution since batteries are much denser in terms of mass per unit volume than Kerosene...)
Yeah, the math section is wrong almost from the start because of this. The work equation isn't simply force times distance. It is force IN THE DIRECTION OF TRAVEL times distance. Vertical and horizontal forces on the aircraft don't contribute to work, because the aircraft has zero velocity in those directions. Think of a blimp: it isn't doing work by floating, even though it has large forces from lift and gravity. If the blimp turns on an engine and starts pushing forward, then it is doing work, but the vertical forces still don't enter into the amount of work being done.
One could argue that even though the aircraft has zero vertical velocity, the air being pushed down does not, so it still makes sense to use this equation. But the motion of the air around the aircraft is complicated and the equations here go too far off base to be worthwhile.
Beyond assumptions that might be wrong regarding swept area, one place where this analysis goes wrong is at 4:39. We're solving for Delta V sub z (downward velocity imparted to swept air) based on an assumption of how much mass of air the aircraft is passing through per unit time, which depends on the swept area around the aircraft. If that mass of air is huge (long wings) then that velocity is smaller. If that mass is tiny (short wings) then the velocity is higher. So the velocity imparted depends on the mass of the air. Fine! But in the lower equation, that velocity is multiplied by the mass of the aircraft. But that's not the mass being accelerated! In fact, we already know Delta V sub z for the aircraft: zero.
If we're trying to derive power requirements for moving air, the power equation has to be in terms of mass of the air, not the aircraft.
By 4:44 the equations are really messed up. Because we treated the mass of the aircraft as being pushed by Delta V sub z instead of the mass of air from which we just derived it, we have this squared mass of aircraft term in the numerator for the power equation. That term shouldn't exist. All the analysis after this point doesn't make sense.
Another way to say this: The application of Power = Force * Velocity is wrong, because Force was derived from the aircraft and velocity was derived from the air. Power = Force * Velocity was derived from Power = (Force * Distance) / Time. This equation is correct when the Force is being Applied over some Distance in the direction of travel. But the Force from the aircraft is not being applied over a vertical distance. There is no vertical component to the aircraft's movement.
" (planes don't pay the energy cost for Lift, they pay for Drag- which is much smaller) "
That's simply wrong. On an aeroplane at its most efficient cruising speed about 50% of the power is used in providing lift and about half in overcoming in drag. It is possible to design planes with much larger wing areas which fly relatively slowly to reduce the proportion of power spent on the lift element, but they aren't very conducive to acceptable journey times.
Providing lift requires power. The lift in free air is precisely equal to the rate of change in the momentum of air deflected downwards. It's straight Newtonian mechanics the lift must equal weight in level flight. The larger the mass of air that can be accelerated downwards with the least increase in velocity, the better as the power required goes to the square of the increase in downward air velocity, whilst the momentum change (force/lift) varies only linearly. Larger masses of air moved downwards, means bigger wings and flying slowly as drag increases.
The idea that the power costs of lift is somehow insignificant is just wrong.
@@rychan0 Another one that gets it wrong. The video is talking about the downward deflection of air that provides the lift, not the downward direction of the aeroplane. The lift is the rate of change of momentum of the air downwards, and that takes power. As the only source of energy in an aeroplane in level flight is from the engines, then that's where the energy to accelerate air mass downwards comes from.
There is no law that says just because an aeroplane has thrust from an engine in a horizontal direction doesn't mean that some of that isn't used in accelerating a mass of air downwards. That's exactly how planes fly, by a combination of Benoulli's principle and, more importantly, the angle of attack of the wing.
If you have trouble with this idea, think of a hovering helicopter. It's not moving anywhere, yet it is using immense amounts of power. Where is that power going? It's going into accelerating a lot of air downwards (on top of the thermodynamic losses of course).
Shockingly everyone is assuming that battery energy output will be applied to the kinetic displacement of turbine technology..smh
intercontinental high-speed trains linked to the Belt and Road Initiative
This is like the 3rd time this guy used footage from my country. 1:03 Slovenia Ljubljana. Great stuff thanks...
Your voice is so soothing that i want to actually watch the entire video. GG
New subscriber btw
8:46
Bio-fuel! (Maybe synthetic fuel, but not to hopeful about that.)
In the form of butane, and some cutting-edge fuel cells to power electric distributed propfans.
I think you forget to take into account the fact that electric planes would be able to fly higher due as the electric engines would not require oxygen to burn, leading to a lower air resistance. This would however require a faster, more aggressive ascent, but if we were to put solar cells on the planes, the altitude and exposure to the sun would most likely make up for it?
Idk, I’d need to run numbers to be sure but it’s a theory
The props still need air to move.
Pyaro217 normal engines do not need oxygen to “burn”
Planes run into the lack of air being a problem for lift much earlier than the lack of oxygen for combustion.
What are we gonna do with the solar cells? That's gonna add more weight than the efficiency it would increase, plus this plane won't lose weight while flying, so the range is fixed
The ability of an aircraft to fly higher is directly dependent on the amount of lift the wings can produce, which is directly affected by the shape of the wing as well as the weight of the craft. More factors to account for: Even the most advanced and efficient batteries are extremely heavy and bulky when you scale them up to the size needed to be the sole power source for a commercial aircraft, more weight reduces maximum altitude and reduces efficiency. Flying at higher altitudes also means reinforcing the structure of the fuselage and rest of the craft in order to withstand the pressurization load necessary to keep the crew and passengers alive. All I'm trying to say is that it is such a more complicated question to answer than just saying "Yes they could fly higher."
Just stumbled upon this channel recently and I'm impressed with your aviation videos and the level of detail. Thanks for providing quality content!
Quality content? This should be flagged for mininformation. His grasp of simple mathematics is sorely lacking!
Why not distribute the passengers of a A320 into multiple Cessnas, then station aircraft carriers 2hours appart in the ocean, where they can land and swap their batteries?
seasong It will be really expensive to do it in that way
The obvious answer is that Cessnas are two-seaters, so you could only sit one passenger in each, the other being a pilot. (Or two if you assume there's no pilot and your cessna is an autopiloted drone). So to convert an A320 sitting 180 passengers into cessnas, you'd need 180 cessnas. Surprisingly, 180 cessnas are cheaper than an A320, so that may be a viable solution, financially.
DIERSTEIN Julien 180 Cessnas flying at the same time and with only one pilot sounds a bit dangerous
Damn it's time to buy some Cessna stocks
They don't need to be flying at the same time. That way you can also have them take off as soon as the passengers are ready to embark, giving more flexibility to your schedule.
The obvious drawback of course is that it would be hell to manage a fleet that size, and maintenance costs would skyrocket.
does anyone know where he got the mass of the batteries required at 5:57 mins in?
Aaron Mansfield It’s written in the subtitles. Anyway it’s power divided by the density of power (35kW / 0.340kW/kg)
1:04 in Slovenia...Toplarna Moste
I'm a bit concerned that pressure difference around the wings were never mentioned. Maybe it's included in that downward air stream that was mentioned around 4:20 but I felt like it's excluded. Very interesting video none the less, thanks for sharing!
How would this be affected by using solid state batteries instead of lithium ion batteries
Umm.. in a very real sense, all batteries are solid state. Or, was your comment just meant to be humorous?
We need iron man's reactor
So tell us when you get er done, okay? (There is a dandy cave in Afghanistan you can rent reeal cheap!) (Please bring your own Plutonium, okay?) BYOP.
I'd like to see the results for a hypothetical nuclear-powered airplane. The energy density is hugely larger!
Been tried in the 60s already. Shielding makes it too heavy to be useful.
He did a video on this. Go check it out
John Galt Muh nuclear is bad on a plane. Liquid reactors work well unless the crack in a crash or something. Plus, isn’t uranium heavy AF?
@@nikobelic4251 it’s heavy but extremely energy dense
@@-p2349 airplanes are ALL about weight
Another issue with using li ion cells is that it is extremely dangerous especially when in that big of a capacity. They could use those new ceramic batteries though!
Aluminum-air batteries will make battery powered flight possible.