Over the last three years I have been monitoring the web for evidence of large, heavy lift, commercially capable systems, for loads in excess of 10Kg
As many of you may know, there are a lack of larger frames on the market, that can handle more than 10Kg.
Rimcopters can manage 40Kg loads, and more!!!
From my research, I have found that many "heavy lift" frames are lacking one thing or the other. Either they are too heavy, or they are not strong enough. In both cases the frames are made using "tube and plate" style assemblies.
Three years ago I began developing a new type of multirotor frame. The basic idea came from my experiments with Aluminum extruded tubing as a core frame...bike rims.
This may sound quaint, perhaps even a bit tacky...bike rims for Commercial sUAS and UAV's...
I admit, its easy to get the wrong idea... I am not out in the dump collecting old bike parts to make recycled cheap frames! Stick with me for a bit, and discover why I kept going with this idea, and where I ended up :)
First, let me say that I am not here to bash anyone... There are millions of dollars invested into various manufactured designs, and those dollars are worth protecting!
It is not my desire to obliterate others hard work! My goal here is simple : make the best multirotor possible ! The fact that what I have made is less expensive, and easy to buy and build... That it is made entirely of stock components... And can be reproduced in any part of the world may be concerning to some... I am only here to show that what I have made has value, is useful, and may help some of you in your goals.
Please, if you are offended, or don't have anything useful to add... Please refrain from offering any comments!
If you are an operator, and individual or company that see's value in the work, please contribute !!!
I do not sell frames, or systems... I learned that lesson!
I do not have a business, nor do I intend to create one... So relax! Just enjoy the ride, and take from it what you can... If you intend to take this idea, and make a business... Beware ! I will not tolerate it, and ultimately, it would be better to just ask me to use the design, and pay for that use.
Individuals, who would like to reproduce my results may do so, for their own use... Make one, use it, and prosper! However, if you intend to make them for commercial use... Please remember that this is my intellectual property... And I can and will protect it :)
Now, onto the good stuff
Rimcopter is a TYPE of multi rotor frame, not a brand. To be honest, I didn't even coin the phrase. The name simply denotes what it is... A multirotor made from bike rims.
WHY BIKE RIMS?
Thanks to 100+ yrs of production and development, the bike rim is lighter, stronger.. Less expensive than custom designed parts to do a similar job.
Tube and plate designs could never create the same strength to weight ratio's apparent in my designs, nor can the tube and plates adequately deal with Vibration and Deflection issues... The truth is, Tube and Plates could never be expected to hold the weight, and as a result of the design, they suffer from vibrations effects... Jello, lack of resolution, and over loaded flight controllers, trying desperately to over come the errors created due to motor deflections and stray vibrations!
Rimcopters are completely different. The flight controller and loads are completely isolated from the drive system. In addition, the strength to weight offered in the frame reduces the load to the motors substantially. The result is longer flights, with greater flight ability and performance... Without any complications from stray high frequency oscillations or motors moving all over the place...
When I say lighter, I mean MUCH lighter... In any given example, our frame design will be lighter. Sure, you can make a light tube and plate, however, it would never been strong enough to handle the loads!
AS an example, the 1000mm X8 Aluminum design, AUW of 1.2Kg including 30mm CF Landing gear (can take 200Lbs !!)
Y6 Carbon 900mm... 780g
In both cases the frames can take well over 150Lbs force, before ANY movement / deflection.
AS comparison, I can deflect the motors of a s900 with just two fingers... Less than 10Lbs force.
Too good to be true?
Not at all... The strength of this design is that ANYONE can produce one for them selves, and because of that, it is unlikely that any larger corporation will attempt to produce it.
So, you can see, its not marginally lighter... less than 1/2 the weight in many cases!
not slightly stronger... Exponentially stronger!
Not slightly less expensive... Frames can be made for as little as $75 - $150.
So then, what are you waiting for ?
Need a larger, stronger, less expensive frame ?
Of course you do!!!
What I can offer...Two formats ( X* and Y6 ) , in two sizes, from three materials ( carbon, aluminum or steel)
Welded, bonded, or bolted...
Heck of an idea, and your designs are gorgeous.
The commercially available heavy lifters I know of are the Foxtech D130, Gryphon Dynamics 1400mm frame, and MikroKopter's "big quatro" and Octo XL. Here's a video of the Gryphon frame at 28kg Auw: https://www.youtube.com/watch?v=onWyHq0nhqA
Don't know much about the Mikrokopters and Gryphon, but I fly the D130. It's borderline at 18Kg+, ok around 15kg. Would not really work at 20kg+, although a new re-inforced version is probably ok at 25kg ...The weak points are (retractable) landing gear, and center plate stiffness. The arms are 30mm 1mm thick, center plates are 3mm thick. But this variant would probably work up to 25kg or more ...:
One thing is that for anything above 15kg AUW, an X8 1000mm frame is not going to cut it as you need propellers larger than 24" (for any flight time longer than 5 minutes). Tiger motor U8-U11 will take 28"-30" propellers and I think your design would be great with a 1300-1500 X8 frame.
The only downside I can think of with your designs so far is lack of foldability (important at these sizes) and no retractable landing gear. No retractable landing gear is not a show stopper most of the time. And a few bolts to remove the rims if the arms were pivoting would be ok.
I really like your idea of "rim" reinforcement. I can see how you could get away with lighter and weaker (straight) arms yet get a stiffer and lighter frame overall.
Any idea about the sort of frame weight you could achieve with a 1,400 mm quad design, say suitable for 30kg Auw?
Great work, cheers!
We have folding options for 25mm and 30mm
For an X* frame, 1400mm, it can take 60Kg load ( KDE 71215-135 on 90A with 30x8 on 12s)
That would be the welded aluminum frame. you could use it in a quad format, for your load, however, I would use Y6, or X8 for that application.
Also, retracts are optional... yet in most cases out systems are used for fixed loads (LIDAR) and do not require retracts.
I have a M10 style gimbal assembly, that gets rid of the complication of retracts... and protects the camera / sensor in the event of a crash
The thing is... The Gryhon is no where near strong enough!
In comparason, it is tissue paper :)... and the cost...
Tube and plate designs are noodles... they may "work" to a degree... however, compared to the rimcoipter design, they are overweight, and not even close to as strong! Also, the vibration loading!!!
Really, rimcopter is in its own class :)
What about this http://www.suasnews.com/2015/10/38967/airnamics-r5/
Well... first thing is the cost... The frame looks like its going to cost some bucks to produce.
The welded aluminum frame I have will likely still b e lighter, and everybit as strong.
Not to mention more compact!
Its a looker, for sure, but from a practical standpoint, its doesn't seem to be a great value, and from a commercial standpoint, it will cost more to produce and distribute, by a few million I would say.
So I think, this is the line... proprietary, custom design... expensive, and difficult to reporduce in volume
Rimcopters... inexpensive, eaasy to reproduce for global markets... greater value :)
Yes, by "quad" frame I meant four arms, but X8 of course.
Unclear on what you offer. Full frame with center plates, motor mounts, landing gear, etc ... or just rims? Website?
Impressive, and like the prop guards.
I am not sure I buy the 3 hours flight time with 15kg payload on the hybrid version though ...
I offer complete frame designs, for 500g upto 60Kg
I have also made a few "RTF" systems
Every component I use is from Stock supply... so I could even just provide the component list, for you to build your own.
My component selections include top quality parts ...CNC hinges, CNC aluminum motor mounts, CF frame plates and battery trays... lots of options for different configurations!
If you have a specific application, then I can help to define the components required.
I have to wonder - the forces on the arms are almost entirely vertical (plus torsional). Sideways-forces must be relatively insignificant.
Would there not be more efficiency gains to be had in principle, then, by (somehow) bracing the arms vertically rather than horizontally using the bike rims? (using a vertical centre-pole above, perhaps)
Also, I think, somewhere, I've seen 'ring-quads' (or octos) using an entire bike rim as the outer ring on which the motors are mounted.
the torsional effect is the issue... vertical flex, if not associated with torsional deflection is fine.
In this design, due to the way the rims are designed to clamp on the tube ( clincher) there is little flex or deflection whatsoever at all... this is mostly due to the short booms lenght.
Tube and plates would need to make massive plates to cover the area ( think Ricopter) and that results in a a HEAVY frame, that still loads the FC with stray vibrations.
The original rimcopter was a single rim... its a design shared by a few, including another member of this group.
have a look at my original thread, from RCgroups:
What I did with that design was make it more usefull... modular, scaleable... and so on.
This copter is in development..
70 lb payload..
Extract from their web site:
Here is an unedited photgraph taken at the end of a product shoot – the brick test!
In this picture the Hexa is supported on three arms only, at full 1200mm span… and sitting on top of the centre plates are 28kg of house bricks. It could have taken more had there been more bricks available.