I am very excited to present ObliX to you! ObliX is my multirotor-blimp-drone idea, which will hopefully combine the flight time endurance of a blimp with the agile dynamics of a quadcopter.
The largest dimension of this hybrid-blimp would measure about 3 m and the lifting force of the helium volume would be close to 3 kg.
Starting to build ObliX, I decided to make a development blog about it. To be able to present and discuss the progress in just the way I like, I thought it might be a good idea to make my own website for it. So here it goes:
http://danielwibbing.wix.com/oblix
It would be awesome if you would have a look at my website and support the develop ObliX with your comments. Maybe you would even like to become a member of the development team? Go ahead and contact me!
Comments
There is a 3D view of ObliX now available on:
http://danielwibbing.wix.com/oblix
I did this with Sketchfab and it was really easy. Unfortunately all the colors and the sketched ropes connecting the ends of the rods got lost when converting the Creo .asm file into an .obj file for uploading it on Sketchfab.
Does anyone have an advice for me on how to improve this?
There is a tiny new blog post about the paper envelope available now on:
http://danielwibbing.wix.com/oblix#!blog/c1i69
Well, Daniel, it seems you have some good justification for every design aspect of yours.
I'm looking forward into your progress!
@cedivad: That's definitely a good advice, I will go without solar cells for the first step and add them later. But I will definitely try the use of solar cells at some point because I am a big fan of them. :)
For the balloon material (if that's what you meant), I am considering to use Heptax at the moment.
I think that you should keep it simple, and photovoltaic adds a big and useless layer of complexity. You need panels, transformers, possibly a MPPT, etc. Batteries are much easier, especially at this stage and especially if you can only lift 3kg. You can always lower the battery weight on later and add like half a kg of panels.
Apart from that, the project is interesting. Do you already know what you are gonna use as balloon?
@John Rambo:
Thank you very much for your detailed comment! I'm really happy you take your time to give me your valuable advice! :)
to 1)
The simpler the better, I agree. But except fighting the wind, more likely threats than lightning or gun shots might be birds, don't you think so? Safety and redundancy have always been a big topic on DIYDrones.
to 2)
I agree, the theoretical solar cell power might not be reached by far. This is why ObliX will indeed mainly be driven by batteries. I just wanted to point out that solar cells will significantly increase flight time.
to 3)
I will not just seal two circles together to create the hull. Instead the hull will be made of many lens-shaped segments, creating a real spheroid. The envelope will not be elastic. Failing in my first attempt with the "3x A4 pages of formulas" I just took my measurements from a 3D CAD model of the spheroid to get the shape of the lens-shaped segments. At the moment I cut these segments out of paper and am gluing them together in a very small paper model to see if the spheroid turns out right. I'll post a picture as soon as I am done with that.
However, thank you very much for the link to the excellent book chapter! I will study it carefully.
to 4)
ObliX will have a lifting force slightly smaller than its own weight, so it will descent in case of complete electronic failure. During normal operation the two vertically pointing rotors will cause descending and ascending. As you suggested, depending on the flight altitude, a pressure balance might be necessary. At the moment I am not planing for big heights and am trying to go without this.
Hope to get more comments like this!
@Daniel:
1) reg. motors - I'd start with a simplest design possible. Helium will always diffuse, but you won't even notice it after full day of flight. Doubling motor quantities "just in case" the lightning strikes or someone shoots it with a rifle - don't know if it pays of. Besides, its a balloon - it will soft-land in most of the cases.
2) You evaluate your solar panels to optimistically. From my 28-cell solar system I can barely extract 40Watts (out of 70Watt theoretical). In real-life application looses are everywhere - SMPS efficiency varies from 80% to 90%. Unmatched impedance will cut you 20% extra. Your panels won't be on the plane surface (some more watts lost due to solar inclination), also, shades from your motors will fall onto the panels. You could support your setup with extra solar power, but the machine itself should be driven from batteries.
3) the shape of your blimp doesn't seem natural. Once inflated (I assume two circles sealed one the above other) it will get a shape according to "Elastica Theory" - it will have bigger height => bigger drag. Precise volume calculation will require some serious integration (some 3x A4 pages of formulas).
To give it a shape you want you'll have to go for the gore-design, again, with some complicated math underneath (see: http://www.springer.com/cda/content/document/cda_downloaddocument/9...).
4) How are you going to land this thing, if it will have a lift force bigger than its own weight? You'll need an air compressor and another blimp inside (see Goodyear blimp design).
@Daniel Lukonis: Oh, I have read about this project! It's really amazing! I think it has indeed ben developed in close cooperation with Disney. As far as I know, one of the former students working on this project is now even working for 3D Robotics.
http://www.projectskye.ch/
Very interesting. Good luck!
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