Re: Re: VP-mechanism: geometry symmetry and bearing friction

From: Tapio Linkosalo <tapio.linkosalo_at_iki.fi>
Date: Tue, 16 Aug 2011 13:51:18 +0300

Tapio Linkosalo wrote:
>
> ... it is about time to start building a few new VP hubs for Belgrade.
> One thing to improve with my old hubs is the tracking of the VP arms; it
> seems to me that the spring tends to incline the horizontal bar of the
> hub, resulting in the blade-angle-changing arms become different length,
> and thus the pitch change is not symmetrical. Further it seems to be
> that the 0.3mm axle wire is not sufficiently stiff to resist the
> bending.

Eventually, I ran out of time, tried to build a few new hubs, but these
came way too heavy, so I just put some new propblades to my old hubs.
After all, these seemed to work just fine, and with slightly heavier
spars (around 60mg apiece, as the old ones were around 40), whose
stiffness-es were matched, I had no longer the prop wobble, and also all
steerings were successful (no prop stuck under the wing). So it looks
like my wobble problems were due to prop spars after all, not the hub.

I took some footage of my steering attempts and put it to YouTube:
http://www.youtube.com/watch?v=sMYJehibBTk




-Tapio-
Received on Tue Aug 16 2011 - 03:51:22 CEST

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