DLuders Posted January 7, 2013 Posted January 7, 2013 My girlfriend says you take a Boeing plane, put a Lego logo on it and a stud, and you have your flying Lego. @ Blakbird: Well, you could propose this at your workplace.... You're being very quiet about this topic. @ Zblj: Is it possible to design two pairs of 4-bladed rotors that are geared so that the counter-rotate on different shafts, but which are powered by ONE RC motor?
Zerobricks Posted January 7, 2013 Author Posted January 7, 2013 (edited) I tried 2 4-bladed rotors from a single motor, but the problem comes when trying to reverse one rotor. It requires a combination like 3x8 tooth gears, which is very inefficient. This is why i rather chose 2x Rc motors. Also one motor/rotor allows me compensate for different drag ratios. I am gonna try the double motor-rotor design at school tommorow where there's an adjustable voltage supply. Edited January 7, 2013 by Zblj
S.I Posted January 7, 2013 Posted January 7, 2013 Have you run through the physics, whether the maximum possible lift which can be generated by the motor + rotors is larger than their weight?
Zerobricks Posted January 7, 2013 Author Posted January 7, 2013 If one can lift itself, i dont see how 2 cant?
Phoxtane Posted January 7, 2013 Posted January 7, 2013 Well, color me impressed. I figured this would happen, but in a few years from now! If one can lift itself, i dont see how 2 cant? You're gonna be cutting it pretty close. Not only are the two motors going to have to lift themselves, they will have to lift the frame connecting them. Eventually they'll have to lift four (!) battery boxes, which aren't known for being light. When rocket scientists start drawing up plans for a new rocket, they have to consider the payload and then build stages around that payload. Every bit of extra weight cascades into a need for stronger engines, more fuel to run the stronger engines, and so on, which translates into yet more weight. If they're not careful, the rocket design becomes exponentially larger (and more expensive) for each stage that must be added on. I doubt you'll reach that scenario, since you probably don't have a few billion dollars to pour into a Lego Flight Progam, so good luck
Rishab N Posted January 8, 2013 Posted January 8, 2013 My girlfriend says you take a Boeing plane, put a Lego logo on it and a stud, and you have your flying Lego. I'm breaking up with her.
S.I Posted January 8, 2013 Posted January 8, 2013 Zblj: just was wondering how much force you have left over for payload. Lipko: We already have a lego boeing plane (10177). It just can't fly yet.
OzBen Posted January 8, 2013 Posted January 8, 2013 Zblj: just was wondering how much force you have left over for payload. Lipko: We already have a lego boeing plane (10177). It just can't fly yet. don't provoke him
Zerobricks Posted January 8, 2013 Author Posted January 8, 2013 (edited) So here's the coaxial version test. It floats on arround 15 volts, but any more power to the motors and theit internal thermal fuses kick in and the whol things stops. I have no idea, why this thing is just so unstable, but those few seconds of floating prove the concept for me. I think this technology will be usefull in hovercraft design. Edited January 8, 2013 by Zblj
hrontos Posted January 8, 2013 Posted January 8, 2013 I have no idea, why this thing is just so unstable, but those few seconds of floating prove the concept for me. I think this technology will be usefull in hovercraft design. Also small RC models behave sometimes like that when there are some things around them - air flow is very crazy when there many things around. May be some verticaly mounted panel or plate will make it more stable, since the air flow will try to keep it in vertical position.
Tamas Juhasz Posted January 8, 2013 Posted January 8, 2013 Hi! First of all, congratulation to Zblj for these soultions. I'm just wonder that nobody remembered at this flying Lego machine: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=500935 I made it last year, and this was the really first flying Lego object. It rised from it's own power. Weights 7g. Propeller max rpm was about 10000. You have proved the concept that Lego parts alone can generate enough lift to lift it's own weight, well done for proving the abominable "no" men wrong! It was already proved month ago: I know, it's not an RC controlled helicopter, but the first flying Lego machine. I just wanted to prove that Lego can fly from it's own power.
chorlton Posted January 8, 2013 Posted January 8, 2013 Also small RC models behave sometimes like that when there are some things around them - air flow is very crazy when there many things around. May be some verticaly mounted panel or plate will make it more stable, since the air flow will try to keep it in vertical position. Agreed. It's particularly pronounced close to the ground or flat take-off surface (like your table) where the helicopter will try to move sideways across the surface. I understand you need a human pair of hands to hold the model at the moment but maybe get someone else to hold it - higher and at a distance - while you adjust the power?
Sariel Posted January 8, 2013 Posted January 8, 2013 I made it last year, and this was the really first flying Lego object. It rised from it's own power. I fear this one is a bit controversial. While Zblj's machine is fully self-contained except for a power source, some people may point that you just made a couple of propellers that detach from the motors. I mean no offense, but probably many people see a huge difference between your creation and Zblj's one.
jovel Posted January 8, 2013 Posted January 8, 2013 Making a remote controlled helicopter, I doubt if it's possible ( but I hope you can prove me wrong ) Why not first try to build a hovercraft: Maybe you could use these parts these parts to build the shape.
Zerobricks Posted January 8, 2013 Author Posted January 8, 2013 Been there, done that, but with a bag like the example posted:
Bob De Quatre Posted January 8, 2013 Posted January 8, 2013 Been there, done that, but with a bag like the example posted: Have you tried adding a propeller to that "hovercraft"?? Considering the helicopter challenge, why not add 2 long technic axles at the bottom and make them pass through a fixed technic beam, that way you don"t have to control the stability of the helicopter.... I don't know if I'm really clear...
Zerobricks Posted January 8, 2013 Author Posted January 8, 2013 Have you tried adding a propeller to that "hovercraft"?? Considering the helicopter challenge, why not add 2 long technic axles at the bottom and make them pass through a fixed technic beam, that way you don"t have to control the stability of the helicopter.... I don't know if I'm really clear... Guide rails?
Bob De Quatre Posted January 8, 2013 Posted January 8, 2013 Guide rails? Something like that: That way you don't have to hold the heli with your hand
pluto7443 Posted January 8, 2013 Posted January 8, 2013 Has anyone made a pure Lego hovercraft (except for the bag, obviously) that can actually maneuver and control its direction?
NXTLiftBoy Posted January 8, 2013 Posted January 8, 2013 (edited) It was already proved month ago: Just for the record, this attempt was 4 years ago: Obviously this suffers from the same drawback that the power source is not flying, so it is no sustainable flight but just the inertia of the rotor. Anyway, flying LEGO still mesmerizes a lot of people, and i enjoyed seeing about all our attempts. The fun is in trying, even the impossible NXTLiftBoy Edited January 8, 2013 by NXTLiftBoy
allanp Posted January 8, 2013 Posted January 8, 2013 (edited) HA! Just for the record matey , I made flying lego first by simply putting a standard technic prop directly (but not all the way) onto a 9v ungeared motor, from the floor it had enough gusto to whack the ceiling! That was in about 1995. Edited January 8, 2013 by allanp
locoworks Posted January 8, 2013 Posted January 8, 2013 So here's the coaxial version test. It floats on arround 15 volts, but any more power to the motors and theit internal thermal fuses kick in and the whol things stops. I have no idea, why this thing is just so unstable, but those few seconds of floating prove the concept for me. I think this technology will be usefull in hovercraft design. if you can lengthen the mainshaft the pendulum effect will help stabalise it.
Conchas Posted January 9, 2013 Posted January 9, 2013 I know you have not seen many MOCs of mine. Photos with Technic stuff are even more rarer... It doesn't mean that I do play with bricks and not try to build something... So you started the topic and made me to look for these... they are dated back from December 2010. After some experiments at home, this was demoed at Hispabrick event in Barcelona. Failed self powered flight attempt... Although each motor was not under over voltage conditions. On the contrary!... each one was supplied with a PF Rechargeable Box (7,2V max). It should have been less after a trip from Lisbon to Barcelona and several experiments in that day. See the near take-off moments.... Although this contraption was not prepared for sophisticated torque control, and tail rotor speed was just controlled from the BB 7-position speed control. This is raw material I had never edited and was laying in my to-do-list as many many other things... The videos are in the two links below (don't know if I can embed Flickr videos here) http://www.flickr.co...57632471896321/ http://www.flickr.co...57632471896321/ Have uploaded just these three items to my Flickr photostream. All the other stuff I have is quite repetitive as it was recorded to make a selection and prepare a more detailed video. Before this, at home, I made larger experiments with 6-blade rotors but the drag or the torque was simply too much and the RC motors always slowed down considerably in a mater of 1-2 seconds, making the experiment unviable. I think the current consumed was raising to fast and current limit protection on the PF BBs kicked-in. First ever? off board self-powered unmanned LEGO near flight...
Blakbird Posted January 9, 2013 Posted January 9, 2013 @ Blakbird: Well, you could propose this at your workplace.... You're being very quiet about this topic. I have said my peace on this topic in the past, including deriving all the numbers for what it would take to really make LEGO fly. I don't see the need to belabor the point any further. However, I applaud the efforts of builders to further the LEGO state of the art. Advancement only comes through effort. While I don't feel that true flight is possible with entirely LEGO parts, we are all sure to learn much in the process of trying to get as close as possible. So far we have seen a control line model and now a motor which lifts its own weight. Next steps would be to lift flight structure, then to lift power source, then controlability. I just got off a 747 yesterday with a Technic friction pin in my pocket, so I have already made LEGO fly.
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