Building materials (excluding covering)

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Lily Essence
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Re: Building materials (excluding covering)

Post by Lily Essence » October 25th, 2010, 2:32 pm

Flavorflav wrote:Do you think prop hangers are legal under this years rules?
I'm pretty sure that the ones made out of plasic are not legal, but you can recreate the design out of balsa and a thin drill or stiff wire.
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jander14indoor
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Re: Building materials (excluding covering)

Post by jander14indoor » October 25th, 2010, 3:47 pm

Caveat again, this is not an official NSO website, anything I say here is ONLY my opinion, if you want an official answer submit a clarification on the national site, and so on.

THAT out of the way, not sure why anyone reading the plain language of the rules would think a plastic prop hanger is illegal.
Its not one of the functional components in para 1b that is specifically NOT allowed to be rigid plastic.
It joins two of the functional components (rotor and motor stick) with a plastic tube, specifically allowed in para 1b.
And para 2.e specifically allows the thrust bearing to be a commercial item. The hanger is just a part of the thrust bearing.

So, why the worry that its illegal?

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Re: Building materials (excluding covering)

Post by Flavorflav » October 25th, 2010, 5:39 pm

Because it seemed to me that while a portion of it is a plastic tube, it is not a simple tube and, while it may function as a thrust bearing, it is not a simple thrust bearing. I already put in a clarification request on this, but it sometimes takes them a while to respond so I thought I would get an advisory opinion.

calgoddard
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Re: Building materials (excluding covering)

Post by calgoddard » October 26th, 2010, 9:08 am

Rule 2.b. states "[t]he functional components must not be constructed from rigid plastic."

"Functional components" are defined in the prior sentence and the definition does NOT include bearings.

Rule 2.e. states "[r]otor thrust bearings may be commercially available items."

This implies that an Ikara prop hanger, which is made of hard gray plastic, may be acceptable as a building component in this year's HELICOPTERS event.

You were wise to submit a rule clarification to the nationals web site. I am confident you will get a clear answer. This will remove the risk of a DQ and help others in this event. Thank you.

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Re: Building materials (excluding covering)

Post by Flavorflav » October 26th, 2010, 10:08 am

[userpage][/userpage]I'm more concerned with the next sentence of 2 b. "The funcional components may be attached to each other using tape, thread, music wire, malleable wire, paper, metal or plastic tubes." None of these describe a prop hanger to me. One interesting thing is that all the free flight experts (you, jander, the presenters at the Poughkeepsie clinic) seem to think it is obvious that prop hangers are covered under thrust bearings (2 e), but as an outsider I can tell you that it would never in a million years have occurred to me that a prop hanger was a thrust bearing. When I think of a thrust bearing I think of a donut, and a prop hanger doesn't look much like a donut. That's why I asked the question - the Poughkeepsie presenters said they thought they would be legal, and I wanted to see if people on this forum (and specifically the two of you) agreed.

As a follow-up: do you think there is any significant chance that the SOINC clarifications person will rule against prop hangers? If she does, would you argue the point?
Last edited by Flavorflav on October 27th, 2010, 2:05 am, edited 1 time in total.

chalker7
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Re: Building materials (excluding covering)

Post by chalker7 » October 26th, 2010, 6:19 pm

While the clarification hasn't gone through quite yet, I can just about guarantee that commercially available plastic prop hangers/thrust bearings such as the Ikara one will be allowed. As everyone is saying above, the critical issue here is the definition of functional components. Since the prop hanger/thrust bearing is not defined as a functional component but instead connects those components, it can be made from rigid plastic.
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Re: Building materials (excluding covering)

Post by Flavorflav » October 27th, 2010, 6:45 pm

Thank you. It has now come through, and you gentlemen were correct - a prop hanger is considered to be covered under the thrust bearing rule. New question: looking at the picture of the prop hanger, it seems like one might reduce friction by putting a bead or something similar on the prop shaft ahead of the bearing. Is this customary? Would you consider it legal? Also, what do you think about the legality of the Ikara rear hook?

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Re: Building materials (excluding covering)

Post by andrewwski » October 27th, 2010, 8:33 pm

That was pretty much the way to do it with Wright Stuff. A small piece sliced from the ink tube inside a ballpoint pen usually worked pretty well.

Generally, if something is not expressly prohibited and doesn't violate the spirit of the competition, it's legal. But opinions expressed here are only that.

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Re: Building materials (excluding covering)

Post by chalker7 » October 27th, 2010, 9:15 pm

Washers or beads between the rotor and thrust bearing are very important to reduce friction. While small teflon washers are definitely the best, you can probably get away with more readily available tiny glass beads and some lube without losing an excessive amount of torque to friction.
Ikara rear hooks will fall into the same category as thrust bearings (that is, legal), although I wouldn't recommend using them. Just bend your own out of some music wire, the hook will be larger and I've heard (but never personally seen) cases of the plastic coating on Ikaras cutting through rubber.
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Heytifff333
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Re: Building materials (excluding covering)

Post by Heytifff333 » November 4th, 2010, 4:01 pm

What size is everyone using for their materials?
Wire, wood, etc.?

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