What I meant by economically viable is probably not possible without a corporate budget.
Plus for long flight times a multirotor is the worst choice because it's terrible inefficient which is why no-one has built one with a reasonably long flight time, lrn2 helicopter if you want longer flight times.
>>943058 >>943042 >>943054 10Kg payload is A LOT of payload for a quad too. You have to remember that every extra motor requires more thrust and more power to create enough lift, then you have to add in batteries and etc etc etc. Also the way you fly and any other stabilization electronics add more to weight and power consumption.
The quads out there that can make almost hour long flight times are built as light as possible, flown by good pilots, (idk what you level is, but you don't know how to calculate for your own build, so I'll give you so-so at the very least) and carry virtually no payload.
However building a heli with enough payload for a cinematic camera rig is rather easy, and more realistic. Just much harder to fly.
>>943042 You have to custom build or talk to someone who does custom builds. You're looking in the territory of an octocopter for that kind of payload and flight time. For reference, the DJI Spreading Wings S1000+ can carry 9.5 kg for around 15 minutes. If you know what you're doing in putting a similar bespoke multi together, doubling that flight time is trivial, tripling it, I'd suspect is difficult, but still possible.
>>943093 Eh, I'd start looking for an entirely different solution at about the 10kg mark. I honestly can't think of many reasons why you'd want to lift something larger than that and need control over it (i.e. not using a weather balloon).
If you don't need hover capability, you can actually get hella payload using fixed wings with massively better flight time, but eh, I'm still not able to envision much reason to need that kind of weight in the air with a drone of any flavor being the best choice.
>>943064 >>943058 I have been working on this theory of applying rocketry calculus to multirotors and one of my results say that what I asked is totally possible with commercial equipment under certain conditions therefore I made this thread to see if this result is anything special. So your disagreement is actually a positive. Thanks.
>>943093 You could use a small turbine as a generator which powered high current motors, but the cabling would make it very heavy in which case it may be better to use four turbines with constant speed gearboxes and computer controlled pitch change. In this way though, youd need to carry so much fuel which would require quite large rotors in order to get enough lift. Youd also have to make it all out of honeycomb composite with a composite frame as well.
>>943042 Batteries aren't the way to go. You get to a point where you'd need motors so big/powerful to lift that much weight that it becomes a fruitless task due to needing more/bigger batteries, which in turn add more weight, so you're forever fighting physics.
You'd have more luck with a nitro powered helicopter, but it would be large and expensive, as well as having a much higher learning curve if you're not already experienced with flying RC helis
>>943100 Why the hate? I am only trying to move the technology forward which right now is largely trial-and-error. Sometimes you don't need new tech you need optimization. >>943102 Yeah this is exactly what my theory sets out to disprove; that adding lots of batteries is pointless. There is a "sweet spot" where doing so increases the performance despite common sense that it would turn into a fruitless catch-22 where more batteries need more thrust which need more batteries which would need more thrust
>>943117 Rockets that couldn't hit an elephant from 50 years existed over a thousand years ago. The same technology has now sent spaceships to Pluto. Just because a tech sucked in the past doesn't mean it will always suck, that is a lazy contrarian view of the world
>>943122 >Coming to /diy/ for market research instead of RC forums. >bringing up rockets out of nowhere >implying rocket calculus is a field of math and not just general calculus >not knowing that what you're referring to is called rocket physics. >admitting it's market research after only 7 posts >not being OP >undercover market research after starting dev Nice try m8.
>>943130 Why are you being a neckbeard asshole? I admitted early on what the thread is about, I even apologized yet you re still shitting up my thread with ridiculous pedantic arguments. Please fuck off.
Okay now that that guy is gone, as thanks for answering my question I'll talk more about the concept. It's all about optimizing the mass ratio, this is what rockets do. On first glance a rocket seems like a road to nowhere because if you make 5% of it fuel just like a car it goes nowhere. And common sense says that making it 80% fuel is even worse because now it's too heavy to fly. However if you do the maths it will work and all modern rockets work on this principle i.e most of the rocket is fuel. Now if you apply this to electric multirotors it will and it won't work. I found that there is a small region where a high battery to payload mass ratio is advantageous, Higher than that number it will never fly, lower than number it won't lift as much. all current multirotors operate with a ratio lower than this optimum therefore they are underperforming. That's the concept anyway and I'll test it out and report back if anyone is interested. Sorry this was a market research thread I know it's douchey but I needed to know how good current /diy/ drone builds are compared to what my concept says they can be.
>>943113 Yeah, there's a point where you maximize the thrust to weight ratio, but rocketry calculus isn't the way to go, as fuel reduces the weight as it's expended and batteries, well, don't. It sounds more like an optimization problem than any of the standard rocket equation that's unique to rockets (instead of ordinary thrust and weight calculations).
I'm not sure why you brought in "rocketry calculus" when it seems clear you're talking about an optimization problem that has very little to do with rockets.
>>943143 That doesn't even make sense. More batteries =/= more lift. More engines == more lift with lower flight times, so more batteries are added to increase the flight time, adding weight and lowering the effective lift (which is the balancing point, not the bullshit you said about adding more fuel to payload without ANY MENTION of adding thrust).
>>943153 Ok well it's all about mass ratio that's the only link really, I got the idea from it, but youre right there is that key difference where mass gets left behind in rockets. >>943149 No-one seems to bother. Commercial market all have small battery mass understandably to save money, hobbyists sometimes chuck on lots of batteries but it's trial and error (there isn't always a optimum solution so trial and error wont work) and corporate specialists seems to just go straight for the high end gear which shows they never optimized if my equations say they could have gotten the same performance out of budget hobby equipment.
>>943097 >>943113 >>943143 >>943153 >basic optimization-engineering problem >asking /diy/ for help on something that can only truly be achieved via math, testing, and/or simulation
You could have asked one of the many advanced, RC-specific forums and gotten far more actual help. You need to take into account every variable of the craft, down to the shape of the props, etc. if you were actually serious about getting very high optimization from this.
A true engineer could run this math and build prototypes for this rather easily if he were just trying to reach OP goal, and certainly wouldn't want help from /diy/. Something tells me this is either a school project or startup operation. If it is, /diy/ would be more forgiving because then you don't sound full of it.
>>943157 Is pointing out that you're not taking into account that batteries don't add thrust, and don't lose weight (not enough to be important) as their energy density decreases, and in fact, effectively do the opposite of rockets, since the amount of thrust they allow the motors decreases over time with weight being constant, unlike rockets which have a pretty constant thrust but decreasing weight.
Therefore math for optimizing rockets is useless for this. Which begs the question, why is it relevant. What kind of math are you proposing. You still haven't asked anything more than "is it possible" which it is, in a way.
>>943161 Uh if you actually read the thread you will see that nowhere did I ask /diy/ for help. This thread was to gather information as to what the RC community currently believes to be possible. >>943164 I already said the link is tenuous. More inspiration than solid link.
So op...you're obviously doing some rather elementary calculations here. What makes you believe that no one else has done them before?
There's literal teams of engineers around the world and thousands of knowledgeable hobbyists (many of whom are professionals in various astrospace fields), and organizations like the Air Force and NASA running numbers, testing, and experimenting with how to maximize performance envelopes for these things. How confident are you that all of these people either have entirely missed what you're doing or have found it and found it incorrect in some aspect (or more likely, you've messed up somehow)?
>>943184 >>943186 >>943191 Every time someone asks him that, he's sticking to "It's market research" His misunderstanding of basic aeronautical math tells me he's not an engineer. His misunderstanding of actual market research tells me he doesn't work for anyone.
I can only assume he's either weird ass b8, trying to put together some sort of small business idea, or, the most likely, was referred here by /wsr/ for help finding research on the RC community for a school tech or psychology project.
>>943186 This is about reducing costs. >>943191 >"Why bother doing anything when NASA could do it better?" Great philosophy you have there. Sure NASA could do it better but that all depends on them actually doing it in the first place. I don't see NASA-branded drones in stores do you? >His misunderstanding of basic aeronautical math tells me he's not an engineer. Can you please explained this alleged misunderstanding of basic maths? I am very intrigued as to how you came to this conclusion seeing as I have posted no maths whatsoever in this thread > trying to put together some sort of small business idea This is correct. is that bad?
>>943211 >"market research" It's not bad, but being this vauge makes you seem more a wanker than you really are.
Also, as I've said before, /diy/ is far from a good representation of what the RC community thinks. There are many RC guys on /diy/ yes, but you would be better suited elsewhere.
The way you are talking and the way you are vague makes this entire thread seem like a "my math prof said i was very good so I obviously can make something that no-one else has thought of or tried. " thread. Your posts have confirmed this for me
Example of your misunderstanding of math? Stating that you use math that applies to a specific thrust system for one which it is not related or applicable. Claiming this will work because "not everything is intuitive" Acting like this is some crazy complex efficiency calculus, which you have not shown any evidence other than "I used rocket-specific math for electric powered aircraft".
This is just basic efficiency 101. If you were really an engineer who was really concerned about the optimization, you would have calculations for prop designs, weight distribution, and many other factors. Not just basic weight:thrust:fuel ideas.
>His misunderstanding of basic aeronautical math tells me he's not an engineer. Can you please explained this alleged misunderstanding of basic maths? I never said simply basic math, I said basic aeronautical math, which is actually up there on the math complexity scale.
>>943210 >I don't see NASA-branded drones in stores? NASA never once sold a microwave or Tang. Your point? >Assuming I meant "don't do anything NASA could do better" No, that's not the point at all. The point is that there are many, many literal experts, the best in the world at this stuff--which incidentally isn't a new form of technology. Power:weight ratios of various control systems have been around for a fairly long time. RC aircraft have been dicking with this kind of thing for ages. You're assuming that you've come across something, and from the way you're speaking you're not very sophisticated in this field, that none of these experts examining this exact same field have missed.
I'm saying that odds are greatly stacked against it being true that you've noticed something that this many people haven't. I'm saying that the best odds are on the fact that you've somehow fucked up in your calculations, are leaving out some very significant factor, or something along those lines.
>>943219 >>943221 The only way to beat appeal-to-authority arguments is to show physical evidence so until I can do that there is no point in arguing further with any of you. However I'd appreciate if you could answer one more question for me: If I said that a hex with 15" props powered by 444 Watt-hour batteries can theoretically lift a 70 kg human for 10 minutes would you call bullshit?
>>943229 Maybe, if I had the time to fire up the old CAD-o-rama. There are more variables involved too.
You asked about possibility to which we said yes. Then started spouting bullshit about rockets in a way that makes it sound like some autist who thinks they've made a breakthrough looking for asspats. That's why everyone is rustled at you.
>>943229 >>943245 But go ahead OP, prove us wrong, develop something with a breakthrough that no-one has ever thought of or tried, and make it cheap enough to be marketable to anyone but the DOD.
But if you fail just remember we'll all be laughing at you. Pressure is the best motivation I always say.
>Uh if you actually read the thread you will see that nowhere did I ask /diy/ for help. >>943229 >However I'd appreciate if you could answer one more question for me: If I said that a hex with 15" props powered by 444 Watt-hour batteries can theoretically lift a 70 kg human for 10 minutes would you call bullshit?
>>943234 >in a way that makes it sound like some autist who thinks they've made a breakthrough looking for asspats If this were true you had 2 options a) stay calm and say "come back when you can show it working" b) shouting me down with such ferocity that it is painfully clear that you are utterly insecure about seeing others succeed.
Alright OP, you go ahead. You're the one citing fallacies that haven't been made and making a pointless thread by asking incomplete questions on 4chan. No-one here has claimed to be an expert.
People have determined what the battery sweet-spot is. Electric motors are not rockets and only the duration of the lift is changed by the batteries, not the amount of it.
I don't care if you succeed. In fact as a RC and sport pilot myself, I would love to have an economically viable system with the capabilities you suggest.
However, it is not generally accepted for someone to come into a thread, talk down to users like guinea pigs, and then be 100% confident that you're competent when it's pointed out that there might be a chance you might not know what the fuck you're talking about.
>>943266 For the third time I am sorry I treated you all as guinea pigs, don't know what else I can say. >Electric motors are not rockets and only the duration of the lift is changed by the batteries, not the amount of it. Well I disagree, the amount of batteries can change lift in some cases >I don't care if you succeed. In fact as a RC and sport pilot myself, I would love to have an economically viable system with the capabilities you suggest. That's excellent I look forward to having you as a customer. Look out for me on Kickstarter.
>>943278 OP, now that the raeg has worn off, if all you wanted was research, your best option (on /diy/ at least) Would have been to ask your first question, wait about a day or so to see if any anons flame each other, if not it can generally be assumed that most agree with the answer. If this is not the case, you average the two sides of the argument and create a percentage of those who think it is possible, and those who think it isn't. Then after the first question satisfies you, either right after or during the peak of the last question ask your second.
You completely RUINED any usefulness of your test by revealing it even existed. And, quite frankly, made yourself sound somewhat pretentious in the process.
Another tip OP, remember that you can't sell a product based on one feature alone. If it can fly for 40min with 10kg that's great and awesome, but it has to compete with other, more well known drones and still make a profit, otherwise someone will buy yours, take it apart, and come back to /diy/ to tell people how to do it cheaper/better. DJI and other manufacturers will probably still crush you if you can't compete with their support, equipment, and prices.
Also you came to /diy/ with a thread like this. Flaming was inevitable.
>>943286 You're right I fucked this up. >remember that you can't sell a product based on one feature alone. Gotcha, there are a range of other features, together I hope that it will be a fully patentable system. >>943285 Magic.
>>943093 >At what point do you just say fuck it and start using gas powered engines? Around this point, maybe even before it. >I bet that is a nightmare of a control issue though lol Just make it sequential gas-electric. Use brushless motors and speed controllers and flight controllers like normal, but have a gas engine in the middle turning a generator instead of batteries. Shouldn't be that hard.
>>943288 Multis are better platforms for photography/filming. Much, much more stable platform. Down sides are shorter flight times, less payload, and slower...but really speed is the only significant factor these days.
>>943292 I don't know what the military has but I know that all attempts to do this has failed in the commercial market because consumer grade generators and petrol engines are heavy as fuck. Also energy conversion efficiency losses. Petrol will not work on the small scale.
>>943299 >commercial market What commercial market? >consumer grade generators and petrol engines are heavy as fuck. Obviously a major issue. You wouldn't want to use a commercial 4-stroke ground-power generator; that would be FAAAAAR too heavy to ever pencil out. But a 2-stroke motor (like what they already use on giant-scale RC aircraft or lawn equipment) coupled to a rectified permanent-magnet generator (which you could even convert a large RC triphase BLDC motor to) should be light enough and not too tricky. >Also energy conversion efficiency losses. Well, gas isn't as efficient as battery-electric in any way, shape or form, but the energy density of gasoline should more than make up for that. >>943295 Multirotors aren't fundamentally stable, it's the flight controller that makes them stable (which can be installed in CP helicopters as well; see all the flybarless examples and especially those with SAFE by Blade). The only inherent advantage of multirotors over helicopters is simplicity/ruggedness.
>>943360 I have considered petrol 2 strokes and they are indeed light enough but I have yet to find a generator that is. >>943362 I have seen this, i am interested to know how he managed to get the flight controller to work throttle servos instead of motor speed. I however think that it won't be stable if made to move around at speed.
>>943363 What if you had only one petrol motor in the middle, run via chain or belt transmission to each arm, with the flight controller varying prop angle instead of rpm? Just a simple servo for each prop, no extra bullshit. Food for thought, although I'm sure someone has already done exactly this.
>>943042 I wanted to make the same shit year ago. Turns out its better to design it like an RC plane, just 1 propeller and nice wings, weight to payload / time fuel/battery ratio is A LOT more, but if you plan to shoot good aerial footage and such you are stuck with just really powerful drone with big battery and such, check out the gasoline drone at hackaday.com
>>943553 Planes cant hover and are harder to fly. That hackaday drone is awful and this is coming from someone who champions far-out projects. It is made of metal with shitty handmade props (why???) fuckhuge lawnmower engine and awfully flimsy control mechanism.
Can someone please explain counter rotating props in the OP pic? I get that they increase efficiency but where is the sense in doubling motor weight to increase efficiency by 10%? Or does this double thrust by functioning as an octocopter? can you really double thrust by putting two props on top of each other?,what about three?
>>943363 >I have yet to find a generator that is. As I said, any appropriately-sized BLDC motor could be converted to a lightweight, high-power permanent-magnet DC generator with the addition of a simple rectifier circuit. The model aircraft motors are already designed to deal with very high wattages, and I see no reason why they couldn't deliver similarly-high wattages when employed as a generator.
Other than that, just hook it up to a governed gas engine with the appropriate KV and gearing to produce the desired voltage, and run the DC leads from your rectifier to your four ESCs and other DC electronics. That's it. >>943612 Hey, blame the media. Us hobbyists fucking hate it.
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