CTE

[george kennie]

If a digital servo moves one increment of it's total resolution with each
click of the trim lever, then .013 is equal to about 39 clicks of your
trim. Maybe enough to do a big loop?
Probably no where near the realityof the actual, but I'll still bet there
are a lot of clicks involved to move your elevator .013 ( I'm betting more
than 10 and probably close to 20). I'm assuming, of course, that you have
your trim rate adjusted to it's smallest value.
G.

Jeff Hughes wrote:

> I stayed out of this thread earlier. But if you run the numbers for a
> 50 degree temp swing, your only talking 0.013" of differential. I
> doubt if someone is noticing that. Probably the horsepower difference
> over a 50 degree swing makes more difference in how the plane is
> flying.
>
> > Nat
> >
> > I was gone last week....The CTE for balsa will change with the
> density of
> > the balsa it self, but as you have noted, humidity plays a larger
> part
> > here in expansion and contraction. This is not a factor with the
> composite
> > pushrods.
> >
> > I am not as inclined as Jason was to read all those emails while I
> was
> > gone, but in short CTE is not so much a problem as is the mis
> matched CTE,
> > in this case the carbon fiber pushrod vs. the fiberglass fuselage. I
> have
> > not run the calculations but anyone interested assume the CF rod to
> have a
> > CTE of zero, then the fuselage to have a CTE of 6.5 X 10-6 in/in F.
> I
> > would imagine that if you set your trim at 100F then flew in
> December at
> > 50F you may have one or two clicks of trim to compensate.  The
> original
> > post asked about storage down to zero F. In reality the servo arm or
> > elevator would just move with the cold contraction.
> >
> >
> >
> > Gray Fowler
> > Principal Chemical Engineer
> > Composites Engineering
> >
> >
> >
> >
> > "Nat Penton" <natpenton at centurytel.net>
> > Sent by: discussion-request at nsrca.org
> > 11/24/2003 09:24 PM
> > Please respond to discussion
> >
> >
> >         To:     <discussion at nsrca.org>
> >         cc:
> >         Subject:        CTE
> >
> >
> > Gray what is the CTI for balsa ? I have carbon push rods / balsa
> fuse and
> > my elev trim moves around considerably. I suppose it is because of
> > humidity variation between the shop and outdoors ?? The pushrods are
> 50"
> > long.      NatPenton
> >
> >
> >
> >
> >
>
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