drones

No. Believe it or not but drones are old technology thats been around for decades, everythings been tried.

>>1201955
example of this idea falling

>>1201955

I don't know if you are serious, but modern microcontrollers and sensors get better all the time. Drones as we know them have not been around more than a few years.

I'm not sure that a single motor is optimum, but then I have no idea what a magnetic field based gearbox is.

>>1201960
instead of having to control 4 motors to vary the speed of rotation from one powerful motor changing the force of the electric field in the gearbox

>>1201964
>changing the force of the electric field in the gearbox

is that a continuously variable gearbox? my understanding is that they are not efficient and don't last very long.

drones make rapid changes to each motor to maintain the desired orientation and speed. a mechanical gearbox driven by a gas powered engine seems sorta crude in comparison.

>>1201969
no the gearbox is electrical and the magnetic field could be changed to vary the speed in rotation instantly

>>1201969
there are no touching parts inside just a magnetic field so it will last a long time

>>1201952
For fuck sake OP you don't need 4 fucking props. Just turn it into a standard helicopter using a motorcycle engine and give it remote control capabilities.

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>>1201974
>no the gearbox is electrical and the magnetic field could be changed to vary the speed in rotation instantly

>>1201983
>there are no touching parts inside just a magnetic field so it will last a long time

Jesus Christ Superstar you are either an idiot or no wait, you are an idiot.

Nice thread. I had fun.

Is this what OP is babbling about?

https://en.wikipedia.org/wiki/Magnetic_gear

>>1201952
Look up "3d drone" and come back once you learn how collective works

>>1201955
>drones are old technology thats been around for decades, everythings been tried.
This is like saying computers are old technology thats been around for decades, everythings been tried. The state of the art moves on.

>>1201985
The gearbox connected to the motor would be mechanical in this scenario. The couplings to the prop shafts would be magnetic and variable in the amount of motor torque they would transmit.

It's a workable scenario, but the machine would have to run most of the props under full power in normal flight to maintain stability, so that the (constant) output of the motor can allow one prop to overpower the others. That wasted power would probably bleed off into the magnetic coupling system, so the efficiency might not be very good.

Only advantage would be the energy density of the fuel. Otherwise it'll be heavier, louder, less efficient, and (greatly) more mechanically complex than full electric.

Easier to connect the engine to a generator and have 4 electric motors. I would suggest 2 motors per arm and a backup battery for emergency landings if the engine fails. The only real issue is cost, it would be around $30,000 or so to build.

>>1202236

This seems more practical than all that magnetic gearbox stuff. With this idea you can run the gas motor at its optimum rpm, choose the appropriate generator, and you basically have a huge DC power source, and from there on it's just a drone capable of carrying the weight.

As long as the generator (and the backup battery) weigh less than the magnetic gearboxes, this looks better in every way, and if not, it still seems a lot simpler and morel likely to perform like a normal drone.

If you think you have a revolutionary idea for making a new type of "drone", you've failed to, or haven't even tried to Google it

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>>1201985
Is that the bunnings barbecue for harambe?

>>1202236
Pretty sure that would be too heavy.

Would it be easier to go with a twin-rotor pic-related style drone instead? I was thinking you could just have some sort of active differential coupling the engine to each of the rotors. I guess the diff motor and the pitch motor would run off the battery, but they probably wouldn't take enough power to be too worried about efficiency.

>>1202269
No, 30+kw electric motors are only 6kg or less. Assuming one large motor to act as a starter motor and generator + 8 smaller ones it should be under 20kg combined. Trying to find a lightweight engine without resorting to turbines is the most difficult part, you want about 50KW continuous power.

>>1202269
>I was thinking you could just have some sort of active differential coupling the engine to each of the rotors

I'm not a drone engineer, but I'm pretty sure that drones are so awesome because a microcontroller varies the speed of each propellor thousands of times per second to keep the drone oriented the right way, whether it's in motion or hovering.

Trying to use mechanical parts to do this is probably impossible. There's a good reason that it took years to get the first helicopter design to work.

>>1202285
But would that be more weight efficient than just the 8 small motors and a bunch of batteries?

>>1202302
Depends what sort of flight time you want. Batteries have very high power output but low energy storage densities.

>>1201952
>high end motorcycle into a drone
It's not possible and frankly I'd like you to desist. Even if you could get this massive chunk of metal flying I would not like it to be anywhere near me or my family

>>1202311
Equivalent flight time, >2:1 thrust to weight.

>>1202313
You're just jelly because you don't have a 300hp 500lb helicopter.

>>1202316
>Equivalent flight time
Equivalent to what?

>>1202316
>You're just jelly because you don't have a 300hp 500lb helicopter.
How much can you get a 300hp motorcycle engine weight down to? My rough calculations work out to require about 160hp to achieve 2:1 thrust to weight ratio on a 500lb quadcopter.

>>1201952
to little power to weight, possibly. in that regard lypo batterys and brushless motors are hard to beat.

>>1201952
No one has said anything about variable pitch props? You dont spin one prop faster with a single engine kwad you just shift the pitch.
I thought this was an established thing?
Magnetic tranny does sound magical but isnt needed.

I fucking hate quadrotor drones. single or counter-rotating prop helos and fixed wing aircraft are objectively better in every way

>>1201952
>Piece of shit v-twin
>Modern
>Power

Those engines are heavy as fuck and there not modern at all, they still use pushrods and you have to add a tank and fuel that would only make it more heavy. Pls kys you dont know shit about motorcycles or drones.

>>1202320
>300hp motorcycle
Ayy lmao!

>>1202436
>t variable pitch props?

Interesting alternative. How easy is it to control them with a microcontroller?

>>1202477
apparently it has been done; google shows several links

from this link: http://diydrones.com/forum/topics/why-are-we-not-seeing-more-variable-pitch-quadcopters

I am designing a very large (gas powered) quad, and for this application I am planning to use variable pitch for several reasons, most of which relate to safety. For safety, I am using one engine (if 1/4 fails - the loss of control is rapid and violent). If power is lost, I want the quad to be able to descend in autorotation, which a fixed pitch prop cannot do.

As for efficiency, you need to evaluate your flight conditions. Helos in hover have less efficiency (require more power) due to the fact that they are trying to "swim upstream) in their own downwash. Helos in forward flight gain efficiency as the rotor's are constantly flying into "fresh" air (still air, not part of the downwash). The more I work on this project the greater respect I have for the complexity of both the aerodynamics and the mechanical dynamics of a rotary wing craft.

There is no "perfect" design because every little maneuver affects all parts of the system. Forward flight creates different airspeed for advancing and retreating blades. It also changes the angle of attack of the blade. If you look at an airfoil chart, you will see there is usually an "optimum" angle of attack (highest ratio of lift/drag), but once you start considering forward flight, climb/descend, pitched flight, it becomes clear that there are too many variables to "optimize" the blade conditions. It would seem that for quads, much of their time will be in hover (filming, photo, etc), so if that's the mission, design for hover. Others could be for filming moving targets with varying degrees of agility required. In these situations, you will find that you might need to sacrifice hover efficiency to allow a wide enough operating window to satisfy your performance objectives.

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>>1202479

an example of a variable pitch drone

>>1201960
the global hawk has been around since 1998. predator since 94, there has been well over 20 years of droning going on

>>1201952
its called a fucking helicopter, this shit is getting annoying.

>>1202468
this

also aircraft and bike engines are 2 completely different beasts.

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>>1202480
Look up "Stingray 500" for an interesting design.

>>1202494
Couldnt you split hairs further by bringing up the first "drones" were ww2 target practice rc planes?

Dont be obtuse. The subject is clearly on multi rotor unmaned aerial vehichles. Multi rotor being the key here. The tech to do that cheaply is bleeding edge.

STFU predatorass mofo

>>1201983
draw a diagram and show us, it sounds like something you made up that doesn't exist and can't

>>1202480
How do you plan on controlling each rotor rpm individually for yaw?

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>>1202318
Equivalent between "petrol motor + generator" and "straight battery" versions. That's what we're comparing, right?

>>1202476
see pic

>>1202647
Maybe some sort of clutch? It's pretty shitty though.

>>1202647
Not the maker here but you can see the props each have a motor. ESCs.
In a single motor system its done by changing pitch creating drag slightly in the same prop group you speed and slow. This takes less energy, is faster and has a wider thrust range than ramping up a motor. You make the FC think of multirotors as a single swashplate pretty much and fly like a 3d chopper.

>>1202658
>>a clutch

You dont have the mechanical ability to look at that and see servos running up hollow motor shafts? You ruined your own thread with yourself OP. Thats a shame.

Its not clutches magnetic or otherwise. Learn a new word.

>>1202665
Ah, so by increasing the pitch on the clockwise rotors and decreasing it on the anticlockwise rotors you'd get the same lift but more clockwise torque than anticlockwise torque, resulting in a net turning action. I guess same-direction rotors are diagonal from one another.

>>1202671
I'm not OP, I just thought being able to put less torque into each rotor would be the quick and dirty method to vary their RPM. I don't have any mechanical ability at all, I came here from /ohm/ because I was interested in a hoverbike. What would servos inside the motor shafts be used for in a single motor system?

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>>1202676
>What would servos inside the motor shafts be used for in a single motor system?

Altering the pitch of the rotors to change their thrust characteristics without changing their speed. Same thing helicopters do, although theirs is a little more complex, as they also alter the pitch of each individual blade within a single revolution.

>>1202658
>Equivalent between "petrol motor + generator" and "straight battery" versions. That's what we're comparing, right?
Petrol version will be heavier but flight times will be 60mins+ vs 10 minutes with batteries. I would still pick variable speed rotors rather than variable pitch. Variable pitch will require many custom made components. Variable speed only requires you to build the carbon fiber arms.

How much do motorcycle motors weight though? Something like one of those BMW aircooled boxers with a supercharger might be a better option than a sportbike motor.

but motorcycles normally have engines and not motors

>>1202717
If you're building a motorcycle-based copter, then it is pretty pointless to not use the motorcycle's own motor. But going full engine+generator+motor feels pretty clunky, though definitely the easiest way to go aside from straight electric. But I think if you were to mass produce a direct mechanical transmission quad-rotor with variable pitch that it would be more economical for the performance you'd get than the other options. Emphasis on the mass production.

I wonder if quad-rotor would be less efficient than a stacked twin-rotor. I guess the deciding factor would be whether the additional transmission losses would be made up for not having stacked rotors, which is apparently less efficient.

>>1202534
Stingray 500 is a piece of shit. The idea is very Co but the implementation sucks. The kit breaks easily and replacement parts are too expensive for what they are, and the tolerances are looser than a children's toy. I haven't been keeping up to date with it, but last time I tried to buy parts the guy was shutting down shop and running with the money.

>>1204591
Oh, and the damn thing decides to kill itself (three times now) by jamming one of the servos in full open/full close mid-flight. I'd like to replace the controllers for it but mostly lost interest due to what I mentioned so far.

>>1201952
so you want a RC motorbike?
for what?

There is no fucking reason for precise speed control when constant speed+collective pitch is both better and comparatively ancient. Drive them off a common shaft and use swashplate-controlled rotors.

>>1201952
One probably could. But at that size you are going to attract the attention of regulatory agencies.

>> magnetic gears
What the hell are you using magnetic gears for? Magnetic gears are used in practically nothing. Why would you need more than one propellor?

>>1202233
I see where you're going. And you're going to bleed off momentum with electromagnets?

This, but with electromagnets as well?
https://m.youtube.com/watch?v=UNNbLAqK7a4

I understand the concept, but question why you'd rather have 50KW output at all times vs varying your total output and thus, saving energy.

>>1204603
>There is no fucking reason for precise speed control when constant speed+collective pitch is both better and comparatively ancient. Drive them off a common shaft and use swashplate-controlled rotors.
There's a very good reason to use direct drive variable speed electric motors. Shafts, variable pitch propellers and associated components require careful engineering and construction. Brushless DC motors have one moving part and you can easily install two motors per arm for increased safety. There's little chance of 8 motors or speed controllers failing at once. You can even split the battery backup into 8 isolated sections.

>>1204593
Your under the false impression I was telling you or anybody to buyfag on /diy/. Steal the idea and do it better. Its a good concept but not $800 good. Most effitient design noadays is on large prop inthe middle (for that sweet disc load chopper style). With three canted smaller props around the body tricopter style. 25% efficiency increase or so legend is told.

>>1206014
* efficiency (I swear I checked it before posting... sigh)

This is what I was taking about.
https://www.geek.com/gadgets/weve-been-designing-quadcopters-incorrectly-since-day-one-1577256/

>>1206018
That article's comments are a clusterfuck, but it looks promising. But a motorcycle-copter would require the motorbike to be somewhere near the centre of lift, which is also where the main rotor is situated, hence losing lift efficiency, not to mention space efficiency.

>>1204828
Okay, but now you cant lift shit compared to an internal combustion motor.

The benefit of collective control is you can use a combustion motor and ditch the huge shifty batteries.

>>1206436
>Okay, but now you cant lift shit compared to an internal combustion motor.
>The benefit of collective control is you can use a combustion motor and ditch the huge shifty batteries.
You can use electric motors with a combustion engine, a small battery pack is only there to buffer loads that exceed the combustion engine and allow an emergency landing. You can reach 90% efficiency with generator / electric motor combinations, shafts and gears are unlikely to be much more efficient while being less reliable and more difficult to build.

>>1206454
>You can reach 90% efficiency with generator / electric motor combinations
Maybe in a vacuum chamber at zero kelvin. In reality, I think the losses will be much more significant, not to mention the extra mass. Variable-pitch rotors are the ideal solution if you're not too concerned about manufacturing costs.