https://www.youtube.com/watch?v=t5JgnMJzCtQ
I just came across this one.
Disregarding all the usual concerns involved with manned flights of this type etc. I like the technical solution of using many self contained units, each with it's own battery, ESC, motor and propeller. Keeps it simple and adds redundancy at the same time.
Comments
Jason,
With respect to your comments.
"First is safety. If you have an electrical failure or and IMU failure, or a glitch of some sort, there is no way possible, short of a parachute, to save yourself. You can't glide, you can't auto-rotate."
=> The electrical system can be set up in such a way as to limit Single Points Of Failure. The multi props/engine system by design offers a lot of redundancy when one engine fails. The same can be said for the battery system which is set up by multiple batteries(cells) in parallel. The IMU is a point of attention and does require more work in most current set ups.
You do have a point that gliding or auto-rotating are out. Having said that, these days there are multiple manufacturers for ballistic parachutes for light aircraft.
"Second, efficiency. Ok cool, you can get in the air, but theres much more to aviation than just getting in the air. A jet pack can get me in the air, but, they are not very popular forms of aviation. Will this manned multirotor be able to take 2 or 4 people with luggage 200+ miles with ease? I highly doubt it. It might end up as a cool show off toy for some rich guy, but, practical means of transportation? just silly."
=> If you look at the energy demands for an electric multicopter, today's available LIPO's provide flight times of 10 to 20 minutes. So yes, currently you need an additional power source for lengthened flight time. But isn't that similar for regular aircraft?
"So what's the advantage? You have either an incredibly complex electrical setup, or, if you do variable pitch multirotors, you end up with an extremely mechanically complex aircraft that is significantly less efficient than a single rotor or fixed ring, more complex, no means of control if it fails, and it gets less and less practical as you try to increase the payload even further."
I disagree it's mechanically complicated. The manned examples we currently see flying are in essence as simple as simple as a quadcopter. Where is the complicated mechanics you refer to?
"Multirotors are great for small UAV's where they offer increased safety, simplicity, and durability over other platforms, but, scaled up you loose all these advantages."
Show me an example where this is the case?
"I personally think the future of Multirotors in manned aviation is for VTOL capabilities for fixed wing aircraft. Very inefficient thrust used to get the aircraft off the ground and moving forward, then, transitions to much more efficient fixed wing flight, then, back to the multirotors to land."
I think you might have a point here we'll see more of this. NASA has a nice test example already flying. However, I also think there will be a market for pure prop driven multicopters without wings.
Brad, from other post I realize that you have also been expertienting with a manned multicopter. With respect to CG comments you make, what was the CG set up of your manned multicopter? Is there some more information you want to share on project?
@Martin they can get close enough for me,
https://vimeo.com/92324878#t=75
https://vimeo.com/62015113#t=78
@Andrew, multicopters are not at all agile compared to helis. Please show me a multi that can do this --> https://youtu.be/XboXcI9GL0c
The contraption in question is "approx £6000". That's about the cost of a single ticket on an airliner or a day's lease of a smaller aircraft.
For a combustion engine-powered copter to be agile you basically need a variable-pitch rotor which is not something an average person can build. With electric you can scale in size or in number as in the video. Scaling up in the number of rotors lets you keep the extremely fast changes in thrusts unlike just using a bigger motor and props - you can theoretically have a full-size machine as agile as a small acro copter.
And yes, this specific example has an extremely simple and repetitive, if inefficient, electrical design.
But that's not true. The advantages of safety, low cost, and simplicity are negated when scaled up.
Have you seen the price of larger multirotor motors and ESC's? if you're building a X8 or octocopter, the motors and ESC's alone are thousands of dollars. $300+ for 1 motor.
Increased agility compared to what? A heli or plane can be extremely agile and done much simpler at larger scale. For a large prop to be agile on a multirotor you have to use active braking. It's not the same as a 10" plastic prop.
Low complexity? Do you see the electrical system required for this example? That's low complexity?
And getting somewhere with what is available? last time I checked the options for planes and heli's on any scale is much greater. the market for them has been around for 60+ years and there are options from small <1M systems to full scale.
Multirotors are great toys and small UAS applications like putting a camera in the air for 20 min or even a bit larger ones that can fly for up to an hour and do some basic small area mapping, surveillance, etc. For the DIY community, they are great at small scale as when they crash they typically don't break much and usually you replace a $5 prop and you're back up in the air to experiment some more. But again, I don't see any of these advantages translating to large scale when a crash is no longer replacing just a prop and the risk of it falling on someone is no longer a bruise and some small cuts but serious injury or death.
I agree about the silliness if we're talking about transportation, but I don't think anyone's argued this is for transportation. The whole argument could basically be applied to most electric aircraft as well as any project going for materials of lower strength to weight ratio than carbon fiber, etc., etc.
Electric multicopters can have the same (questionable) advantages as at they do at lower sizes. For acrobatics that's agility at low complexity. Low cost, availability of components.
Low complexity, cost and availability is what speaks directly to the DIY crowd and for their uses hackability, thrill, even personalized design and similar factors are often more important than efficiency. For most other users (e.g. TV stations' camera drones) the cost will be the main factor.
Note the "diy" in your address bar, that is, among other things, about getting somewhere with whatever is available rather than getting nowhere.
John, I fully agree with your argument, some or most of these project are interesting and mind and media catching but very far from viable/commercial for manned flight
I mostly agree.
It is easy to forget, but the only reason why quads became a thing in the first place was the simplicity of the design. Two stick in a cross and a motor with a fixed propeller at each tip. Doesn't get much simpler then that.
Efficiency is down the drain, but who cares for a fun DIY hobby project? Them for some reason they became so popular that people started wanting to use them for any task they could think of related to flying, just because it meant instant media attention. Never mind helicopters and plane designs being MUCH better suited for most of those tasks.
But when you start to consider manned flights, the simplistic design no longer cuts it because you need safety. And once safety concerns are meet, then you need practicality which usually translates to range and payload capacity. Both something multirotors just plainly suck at compared to the traditional solutions.
As of right now, manned multirotors are just silly. I say this for a few reasons,
First is safety. If you have an electrical failure or and IMU failure, or a glitch of some sort, there is no way possible, short of a parachute, to save yourself. You can't glide, you can't auto-rotate.
Second, efficiency. Ok cool, you can get in the air, but theres much more to aviation than just getting in the air. A jet pack can get me in the air, but, they are not very popular forms of aviation. Will this manned multirotor be able to take 2 or 4 people with luggage 200+ miles with ease? I highly doubt it. It might end up as a cool show off toy for some rich guy, but, practical means of transportation? just silly.
So what's the advantage? You have either an incredibly complex electrical setup, or, if you do variable pitch multirotors, you end up with an extremely mechanically complex aircraft that is significantly less efficient than a single rotor or fixed ring, more complex, no means of control if it fails, and it gets less and less practical as you try to increase the payload even further.
Multirotors are great for small UAV's where they offer increased safety, simplicity, and durability over other platforms, but, scaled up you loose all these advantages.
I personally think the future of Multirotors in manned aviation is for VTOL capabilities for fixed wing aircraft. Very inefficient thrust used to get the aircraft off the ground and moving forward, then, transitions to much more efficient fixed wing flight, then, back to the multirotors to land.
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