Re: Re: motor stick bending

From: Nick Ray <lasray_at_gmail.com>
Date: Fri, 22 Feb 2013 11:06:35 -0500

A-grain is most flexible, that is why its used for bending around curves.

C-grain is the least flexible, which is why its used for prop blades and
motor tubes. When you first think about it, it seems paradoxical to use the
stiffest grain orientation to roll a small diameter tube, but the goal is
to resist the tube collapsing. Motor sticks start to fail by a section of
the tube deforming under load.

To answer your question a motor stick whose side view shows C-grain will be
stiffest when twisted, but it will perform poorly in compression. A motor
stick with A-grain showing from the side view will perform poorly in
torsion but will be stiffest in compression.

Which is better for our purposes depends on flying style.

Nick

On Fri, Feb 22, 2013 at 10:54 AM, Yuan Kang Lee <ykleetx_at_gmail.com> wrote:

> **
>
>
> I will be the first to go on record -- I have no idea.
>
>
> --- In Indoor_Construction_at_yahoogroups.com, Warthodson_at_... wrote:
> >
> >
> > A debate is raging in our local club. So far the vote is tied. We need
> your input.
> > Imagine two identical motor sticks, same dimensions, same weight, etc.
> When viewing the motor stick from the side, one is made from "A" grain &
> the other from "C" grain wood. Which will resist bowing better, which will
> resist twisting better?
> > Thanks,
> > Gary
> >
>
>
>
Received on Fri Feb 22 2013 - 08:06:37 CET