Lipko Posted December 31, 2013 Posted December 31, 2013 How are you going to make sure that the turntable and the central hub rotate at the same rate? Maybe you could use Suspension A-arms, but the construction would get messy quite fast. Quote
steph77 Posted December 31, 2013 Posted December 31, 2013 the construction would get messy quiet fast and be unequilibrate.... Have a look at the topic of my huey.I used a double synchronised linkage. Maybe it could help you. topic : 68431 Quote
DrJB Posted December 31, 2013 Posted December 31, 2013 (edited) the construction would get messy quiet fast and be unequilibrate.... Have a look at the topic of my huey.I used a double synchronised linkage. Maybe it could help you. topic : 68431 Your Huey was (still is) an epic build. Though, from the limited photos, it is very difficult to reproduce. Would be nice to put some instructions or even an LXF. Granted, some of the old parts are not available in LDD. Edited December 31, 2013 by DrJB Quote
Nachapon Lego Posted January 2, 2014 Author Posted January 2, 2014 (edited) Happy new year! @steph7 & Lipko, Thanks for very nice comment and suggestions. Maybe this model just suit for simulate function(not spin too fast). Connect to three PF or NXT moters to simulate cyclic & collective. Need new mould for turn table uper part and 4x4 round bricks for five blades rotor head and swashplate. Lego five blades roter head swashplate new part concept 3 by Nachapon S., on Flickr Lego five blades roter head swashplate new part concept by Nachapon S., on Flickr Hi , I am very impressed with your work , especially by your mastery of drawing by computer. Great work. However, to have built myself several functional helicopters, I see two major problems in your installation . The first is the binding of the mat of the rotor with the top part of the swashplate . You should create a physical and articulated connection , a mechanical training compass. It is imperative to create this piece because without it the rotation will generate a lot of vibration. Note that fixing the compass must absolutely be made to the plane of the swashplate ( see below) The second problem, which is not the least of which is that it is absolutely neccessary that your swashplate is a perfect plane between the ball joint of the low bet and the ball joints of the upper part of the swashplate . Again, your installation will generate a lot of vibration. In a general way you also must minimize the weight , the mass, of the rotating parts to minimize the problems of vibrations. In short, everything is history of equilibrium mass and homokinetism in the building. And, I know, it's much easier said than done! Otherwise, have you looked at the command system that controls this all? This part of the design is also difficult. from my experience, be careful at the outset points: First set the point of attachment of the rotor mast highest as possible. indeed lego axes are flexible and do not help to solve vibration problems. secondly, ensures a secure and perfecty guided mechanism (vertical and tilting) for your swashplate. this for the same reasons ... Finally, avoids toothed parts in your kinematic chain commands. they generate small 'play' in the mechanism that are really harmful to the proper functioning and stability of the whole. Therefore only uses systems linkage secured and guided. Well, good luck to you, do not hesitate to build a real model, you will quickly realize what I mean with my stories of vibration ... @+ ! How are you going to make sure that the turntable and the central hub rotate at the same rate? Maybe you could use Suspension A-arms, but the construction would get messy quite fast. Edited January 2, 2014 by bbqqq Quote
Thirdwigg Posted January 2, 2014 Posted January 2, 2014 Great topic. Good suggestions on the rotor head. I, like Steph77, am interested in the mounting of the swashplate. My experience with helicopters has found that the rotor head is simple compared to mounting of the swashplate, as it is hard to isolate the controls for the fore/aft and port/starboard from the collective controls. Each must function independently, and as a unit. Great design, I look forward to more. Quote
Nachapon Lego Posted January 4, 2014 Author Posted January 4, 2014 (edited) @Thirdwig. Thanks for nice comment. Three PF motors with worm gears or three NXT motors should tilt/lift the swashplate independently. This is so far working one. I will test it with linear actuators and motor drive later. 4 YouTube Lego helicopter realistic roter head swashplate cyclic & collective sim by Nachapon S., on Flickr Edited January 4, 2014 by bbqqq Quote
DrJB Posted January 6, 2014 Posted January 6, 2014 (edited) Very ingenious and inspiring work as always, especially the 'new' penta-swashplate. It's a pity TLG is not considering new parts anymore for cuusoo (and canceled all your submissions ) In any event, and just from kinematics, the swashplate should have 3 degrees of freedom: 1 up-down translation for collective (to adjust pitch angle / lift) and 2 rotations (pitch/roll) for cyclic. I liked how you captured such 3 DOF with 3 LAs but, from my thinking, it'll be very difficult to 'combine' somehow the 3 motions to yield the three independent controls. This is not meant as a criticism, but rather something to think about for all of us following. I know it is easier said than done, but it might be 'efficient' to have each of the 3 LAs control each of the 3 DOFs (Vertical/pitch/roll) independently (no coupling). That would require some ingenious mechanisms ... though from all you've done so far ... you're up to the challenge Edited January 6, 2014 by DrJB Quote
Nachapon Lego Posted January 8, 2014 Author Posted January 8, 2014 Very ingenious and inspiring work as always, especially the 'new' penta-swashplate. It's a pity TLG is not considering new parts anymore for cuusoo (and canceled all your submissions ) In any event, and just from kinematics, the swashplate should have 3 degrees of freedom: 1 up-down translation for collective (to adjust pitch angle / lift) and 2 rotations (pitch/roll) for cyclic. I liked how you captured such 3 DOF with 3 LAs but, from my thinking, it'll be very difficult to 'combine' somehow the 3 motions to yield the three independent controls. This is not meant as a criticism, but rather something to think about for all of us following. I know it is easier said than done, but it might be 'efficient' to have each of the 3 LAs control each of the 3 DOFs (Vertical/pitch/roll) independently (no coupling). That would require some ingenious mechanisms ... though from all you've done so far ... you're up to the challenge Thank you for your very nice comment. I am OK for many new parts cuusoo projects been canceled. Because it seems like they never reach 10K supports. Maybe three well programed NXT motors can control each of the 3 DOFs (Vertical/pitch/roll) independently. Because NXT motor can rotate very accurate to any degree precisely. I will design and render a hexa-swashplate as well. Nice work! Thanks! Quote
DrJB Posted February 24, 2014 Posted February 24, 2014 (edited) Any update on the hexa-swashplate? Also, can your penta/hexa turntable designs be uploaded to shapeways? Edited February 24, 2014 by DrJB Quote
DrJB Posted March 2, 2014 Posted March 2, 2014 Looks promising, though, can you post an LXF/LDD ? ... rather difficult to guess the construction. Quote
DrJB Posted March 3, 2014 Posted March 3, 2014 I have no idea how to post files on here... Very easy ... reply, then 'attach/upload/post'. Quote
Blakbird Posted March 3, 2014 Posted March 3, 2014 Very easy ... reply, then 'attach/upload/post'. New users can't attach files. Your best bet is to use a hosting service like Bricksafe and then just post a link to wherever you hosted the file. Quote
DrJB Posted March 3, 2014 Posted March 3, 2014 (edited) Correct ... I had not noticed that he's got only 2 posts ... Edited March 3, 2014 by DrJB Quote
Raulboy Posted March 4, 2014 Posted March 4, 2014 (edited) Still working on a scissor assembly for it... Can't get the pieces to line up for me, and as of now don't see a way to do a primary and a backup (one on each side), or whether it'll interfere with the movement. Once I get that, the mixing assembly + torque and lateral links figured out (and pneumatic servoactuators if possible haha), the driveshaft and gear train will come. Link to file: http://bricksafe.com/files/Raulboy/Apache%20v4.lxf (updated from 20m ago) Edited March 4, 2014 by Raulboy Quote
DrJB Posted March 4, 2014 Posted March 4, 2014 (edited) Looks nice, but I can't guess how it'll work ... Will have to build it and get back to you. How about all those parts on the floor, planning to use all of them in the contraption? Edited March 4, 2014 by DrJB Quote
legolijntje Posted March 4, 2014 Posted March 4, 2014 @Raulboy: your construction is impossible to build. The dark grey corner axles can't be put in those black frames with pin You could for example try to use this piece together with an axle. Quote
Raulboy Posted March 4, 2014 Posted March 4, 2014 (edited) @Raulboy: your construction is impossible to build. The dark grey corner axles can't be put in those black frames with pin You could for example try to use this piece together with an axle. You sure you can't jam it in there with a little force? ;) Haha if that's the only thing wrong with it, I'd be amazed... I'm sure I'll find a way to replace it if I really can't get it in there. The parts on the floor are for quick reference- I pulled out all the parts that I thought might help me solve a puzzle or I would need, so I just have to duplicate them when I need to. Edit: Looking at it, the idea I had for driving the rotor won't work as it sits...Not enough room to miss the non-rotating part =( Edited March 4, 2014 by Raulboy Quote
Raulboy Posted March 5, 2014 Posted March 5, 2014 No longer static mast; I couldn't figure out a way to keep it static and still be able to drive it. The static mast wasn't very sturdy either. Finally figured out some scissor assemblies- it doesn't look like they should interfere too much. LXF: http://bricksafe.com/files/Raulboy/Apache%20v5%20change%203.lxf Quote
DrJB Posted March 6, 2014 Posted March 6, 2014 (edited) Looks rather complex. You can have the same functions with fewer parts and more 'legal' connections ... For example: 1. The lower (small) turntable is there to only transmit the torque to the vertical 13L beam (liftarm) ... correct? If so, why such complicated connection between such turntable and the 13M beam? 2. Also, why are you using 2L flextubes on the upper turntable? Might be better to use part 75535 instead ... 3. What do the bionicle parts do? Transmit torque/rpm to the top turntable? Edited March 6, 2014 by DrJB Quote
Thirdwigg Posted March 6, 2014 Posted March 6, 2014 I am watching this thread with interest as an upcoming project is being worked on that needs a rotor head. While many of these designs work, once you put power to them, there is a lot of flex that does not help the controls for the system as a whole. So far the most effective four blade systems that I have seen are this one from Efferman, and this one. Both function very well, but rely on this part, which takes away from the smoothness of the collective. I intend to find a solution. But until you can find a good way to connect the rotation of the rotor mast, and the swashplate rotation, your functions will be sloppy. I'll see if I can post my current work soon. Quote
CP5670 Posted March 7, 2014 Posted March 7, 2014 This thread has some interesting ideas, but the rotors are pretty large and bulky. I think the easiest way to make a full cyclic/collective rotor is to use the old 1990s rotor parts. I believe all the helicopter MOCs with realistic rotors use those in some form. Both function very well, but rely on this part, which takes away from the smoothness of the collective. I intend to find a solution. But until you can find a good way to connect the rotation of the rotor mast, and the swashplate rotation, your functions will be sloppy. I'll see if I can post my current work soon. If you put that CV ball joint on the right kind of axle, the collective can actually move quite smoothly. I used this approach in this model with a white 5.5L axle, which has weaker clutch power than most other axles. Quote
steph77 Posted March 7, 2014 Posted March 7, 2014 (edited) Hi, I really appreciate your work ont that rotor head. From my experience your idea higlight some problems. First, your swashplate is unequilibrated so that the compas linking swashplate and rotor mast will generate vibrations Second, that same linkage will generate to much friction while incorporating the assembly with a full commands linkage system At last, the utilisation of a turntable generates a swashplate where the under and upper linkage are not int the same geometrical plane While you'll inclinate the swashpalte, a lateral displacement will be generated. The upper swashplate's center of rotation will not be aligned anymore with the rotor mast. That will also generate lots of vibrations. That same geometrical issue will also generate bigger angles for the connector between the blades that the swashplate will not be abble to accept. EDIT : (While max collective and cyclic movement will be combined) Whatever, this topic shows that lego are not only bricks :) Good continuation steph. Edited March 7, 2014 by steph77 Quote
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