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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:

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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).

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I tried wrapping string round the pegs and they still wobbled, this one's tricky.

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5-fold symmetries are difficult to build in LEGO, especially at small scale. Here is an attempt, still a bit bulky...

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LDraw file here.

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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

Head based rotor

I now have to decide if I want playabiliy or good looks on the model.

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    If you mount your assembly on a 2x2 rotating tile (3679 & 3680) you have both - playability and good looks :) – Phil B. Dec 9 '14 at 14:23
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    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. – Windfire Dec 9 '14 at 14:30
  • 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. – Windfire Dec 9 '14 at 14:33
  • 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. – Windfire Dec 9 '14 at 14:42
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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.

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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.

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  • 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. – Zhaph - Ben Duguid Sep 2 at 16:55
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    @Zhaph-BenDuguid - Info added, thank you for the interest :) – JohnnyB Sep 3 at 0:20
  • Cheers, very neat, and also cleverly adjustable too! – Zhaph - Ben Duguid Sep 3 at 12:35
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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.

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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.

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