Answers.Body: <p>I think I have a valid semi-legal design, it is good for display models, although Philo's answer to this question provided an excellent design for playing-with models.</p>
  
  <p><img src="https://i.sstatic.net/AY8nU.jpg" alt="Head based rotor system parts"></p>
  
  <p><img src="https://i.sstatic.net/8ZBqM.jpg" alt="Head based rotor"></p>
  
  <p>I now have to decide if I want playabiliy or good looks on the model.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-12-09T14:23:43.657Z
Answers.Text: If you mount your assembly on a 2x2 rotating tile (3679 & 3680) you have both - playability and good looks :)
Answers.UserDisplayName: Phil B.
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-12-09T14:30:23.633Z
Answers.Text: It would rotate better, but there is still a poor connection because of the band as a primary component.  If I used the concept that stickers are 'legal' I could increase the diameter of the heads by applying layers until I have a perfect fit, but that doesn't seem fair somehow.
Answers.UserDisplayName: Windfire
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-12-09T14:33:14.520Z
Answers.Text: To that point, if I was building for a child, I would definately use Philo's design.  As it is, I should build two helicopters, one with each design, and see what I think.
Answers.UserDisplayName: Windfire
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-12-09T14:42:08.533Z
Answers.Text: I mounted the assembly on a technic peg in a 2x2 round brick on a turntable.  It spins very well, but the blades are at different angles every time it stops.
Answers.UserDisplayName: Windfire
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-10-04T17:01:08.543Z
Answers.Text: Use a tire instead of rubber band.
Answers.UserDisplayName: Johnlamarck
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-12-07T23:59:51.500Z
Answers.LastActivityDate: 2014-12-07T23:59:51.500Z
Answers.UserDisplayName: Windfire
Answers.Body: <p>I am intrigued by mechanical problems like these and couldn't resist adding my own solutions in the hope of being helpful.  I threw together the first few ideas I had that were fairly compact and used contrasting colors to help the eyes figure out the building techniques.  They are all raw designs that are free of cosmetic pieces to expose their construction and welcome a builders tweaking for specific applications.  Lastly, if there is anything that needs clarification then please comment and I will add details.  </p>
  
  <p><a href="https://i.sstatic.net/B41oL.jpg" rel="noreferrer"><img src="https://i.sstatic.net/B41oL.jpg" alt="enter image description here"></a>  </p>
  
  <p>Having such a tight middle, the top design requires a very thin axle, like part# 2569 antenna, or part# 93550 sword/foil.  If this is an issue, then adding pieces will open it up giving you more options.  Here is a photo of it pulled apart for clarity and an additional photo demonstrating one of many variations possible.  </p>
  
  <p><a href="https://i.sstatic.net/5vsCE.jpg" rel="noreferrer"><img src="https://i.sstatic.net/5vsCE.jpg" alt="enter image description here"></a><br>
  <a href="https://i.sstatic.net/S22Hb.jpg" rel="noreferrer"><img src="https://i.sstatic.net/S22Hb.jpg" alt="enter image description here"></a>  </p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-09-02T16:55:03.467Z
Answers.Text: Those are all really rather neat - any chance you could expand on the top one a bit more? I can't quite see how that all holds together.
Answers.UserDisplayName: Zhaph - Ben Duguid
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-09-03T00:20:05.050Z
Answers.Text: @Zhaph-BenDuguid - Info added, thank you for the interest :)
Answers.UserDisplayName: JohnnyB
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-09-03T12:35:32.683Z
Answers.Text: Cheers, very neat, and also cleverly adjustable too!
Answers.UserDisplayName: Zhaph - Ben Duguid
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-09-01T06:32:49.950Z
Answers.LastActivityDate: 2019-09-03T00:19:18.367Z
Answers.LastEditDate: 2019-09-03T00:19:18.367Z
Answers.UserDisplayName: JohnnyB
Answers.Body: <p>I know this is an older thread, but I think I've come up with a small improvement on WindFire's build using part# 33492 Cone 1 1/2 x 1 1/2 x 2/3 truncated.  Its slighty larger than a head so it's a tighter fit.  </p>
  
  <p><a href="https://i.sstatic.net/LQXV3.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/LQXV3.png" alt="enter image description here"></a>  </p>
  
  <p>Also, using part# 85861 Plate, Round 1 x 1 with Open Stud allows it to have a bit better hold than the clip connection.  Now to somehow improve the elastic option.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-08-31T13:46:20.580Z
Answers.LastActivityDate: 2019-09-01T07:54:35.627Z
Answers.LastEditDate: 2019-09-01T07:54:35.627Z
Answers.UserDisplayName: Mike Mac
Answers.Body: <p>5-fold symmetries are difficult to build in LEGO, especially at small scale. Here is an attempt, still a bit bulky...</p>
  
  <p><img src="https://i.sstatic.net/EtrV9.png" alt="enter image description here"></p>
  
  <p>LDraw file <strong><a href="http://www.brickshelf.com/gallery/Philo/Misc/rotor5.ldr" rel="noreferrer">here</a></strong>.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-12-07T23:01:45.583Z
Answers.Text: I like this, replacing the 1x5 plates with technic connectors number 1 (http://www.bricklink.com/catalogItem.asp?P=32013) and putting  a rubber band round it makes it a serious possibility.
Answers.UserDisplayName: Windfire
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-12-07T17:30:02.393Z
Answers.LastActivityDate: 2014-12-07T17:30:02.393Z
Answers.UserDisplayName: Philo
Body: <p>I want to build a Super-Puma helicopter in city minifigure scale and form, I have the basic design planned, but I am not familiar with any five-sided technic connectors, which I will need for the rotors.</p>
  
  <p>I have thought of a potential idea, but it is still a little too large for city scale helicopters:</p>
  
  <p><img src="https://i.sstatic.net/QU39D.jpg" alt="enter image description here"></p>
  
  <p>Any better ideas out there?</p>
  
  <p>Update - I had this idea, but it is quite loose, maybe I could tighten it up by using PC dishes on PC sticks (PolyCarbonate pieces used together bind to each other).</p>
  
  <p><img src="https://i.sstatic.net/6560s.jpg" alt="enter image description here"></p>
  
  <p>I tried wrapping string round the pegs and they still wobbled, this one's tricky.</p>
  
Tags: <building><technic>
Title: City scale connection for five-bladed helicopter rotors
UserDisplayName: Windfire
ThreadText: # City scale connection for five-bladed helicopter rotors
  
  (Asked by: username_0 on 2014-12-06)
  
  I want to build a Super-Puma helicopter in city minifigure scale and form, I have the basic design planned, but I am not familiar with any five-sided technic connectors, which I will need for the rotors.
  
  I have thought of a potential idea, but it is still a little too large for city scale helicopters:
  
  ![enter image description here](https://i.sstatic.net/QU39D.jpg)
  
  Any better ideas out there?
  
  Update - I had this idea, but it is quite loose, maybe I could tighten it up by using PC dishes on PC sticks (PolyCarbonate pieces used together bind to each other).
  
  ![enter image description here](https://i.sstatic.net/6560s.jpg)
  
  I tried wrapping string round the pegs and they still wobbled, this one's tricky.
  
  **Tags:** building, technic
  
  ---
  
  ## 4 answers
  
  ### Answer by username_6 on 2014-12-07. Score: 10 | Accepted answer
  
  5-fold symmetries are difficult to build in LEGO, especially at small scale. Here is an attempt, still a bit bulky...
  
  ![enter image description here](https://i.sstatic.net/EtrV9.png)
  
  LDraw file **[here](http://www.brickshelf.com/gallery/Philo/Misc/rotor5.ldr)**.
  
  > **Comments:**
  > **username_0**: I like this, replacing the 1x5 plates with technic connectors number 1 (http://www.bricklink.com/catalogItem.asp?P=32013) and putting  a rubber band round it makes it a serious possibility.  
  
  ---
  
  ### Answer by username_0 on 2014-12-07. Score: 7
  
  I think I have a valid semi-legal design, it is good for display models, although Philo's answer to this question provided an excellent design for playing-with models.
  
  ![Head based rotor system parts](https://i.sstatic.net/AY8nU.jpg)
  
  ![Head based rotor](https://i.sstatic.net/8ZBqM.jpg)
  
  I now have to decide if I want playabiliy or good looks on the model.
  
  > **Comments:**
  > **username_1**: If you mount your assembly on a 2x2 rotating tile (3679 & 3680) you have both - playability and good looks :)  
  > **username_0**: It would rotate better, but there is still a poor connection because of the band as a primary component.  If I used the concept that stickers are 'legal' I could increase the diameter of the heads by applying layers until I have a perfect fit, but that doesn't seem fair somehow.  
  > **username_0**: To that point, if I was building for a child, I would definately use Philo's design.  As it is, I should build two helicopters, one with each design, and see what I think.  
  > **username_0**: I mounted the assembly on a technic peg in a 2x2 round brick on a turntable.  It spins very well, but the blades are at different angles every time it stops.  
  > **username_2**: Use a tire instead of rubber band.  
  
  ---
  
  ### Answer by username_3 on 2019-09-01. Score: 7
  
  I am intrigued by mechanical problems like these and couldn't resist adding my own solutions in the hope of being helpful. I threw together the first few ideas I had that were fairly compact and used contrasting colors to help the eyes figure out the building techniques. They are all raw designs that are free of cosmetic pieces to expose their construction and welcome a builders tweaking for specific applications. Lastly, if there is anything that needs clarification then please comment and I will add details.
  
  [![enter image description here](https://i.sstatic.net/B41oL.jpg)](https://i.sstatic.net/B41oL.jpg)
  
  Having such a tight middle, the top design requires a very thin axle, like part# 2569 antenna, or part# 93550 sword/foil. If this is an issue, then adding pieces will open it up giving you more options. Here is a photo of it pulled apart for clarity and an additional photo demonstrating one of many variations possible.
  
  [![enter image description here](https://i.sstatic.net/5vsCE.jpg)](https://i.sstatic.net/5vsCE.jpg)  
  [![enter image description here](https://i.sstatic.net/S22Hb.jpg)](https://i.sstatic.net/S22Hb.jpg)
  
  > **Comments:**
  > **username_4**: Those are all really rather neat - any chance you could expand on the top one a bit more? I can't quite see how that all holds together.  
  > **username_3**: @Zhaph-BenDuguid - Info added, thank you for the interest :)  
  > **username_4**: Cheers, very neat, and also cleverly adjustable too!  
  
  ---
  
  ### Answer by username_5 on 2019-08-31. Score: 3
  
  I know this is an older thread, but I think I've come up with a small improvement on WindFire's build using part# 33492 Cone 1 1/2 x 1 1/2 x 2/3 truncated. Its slighty larger than a head so it's a tighter fit.
  
  [![enter image description here](https://i.sstatic.net/LQXV3.png)](https://i.sstatic.net/LQXV3.png)
  
  Also, using part# 85861 Plate, Round 1 x 1 with Open Stud allows it to have a bit better hold than the clip connection. Now to somehow improve the elastic option.
  
  
  ---
  
  