CTE

[Wayne Galligan]

That would depend on if you had a low cost Futaba(w/slide trim) vs. a high
end JR(w/digital trims)

Wayne G.

----- Original Message ----- 
From: "george kennie" <geobet at gis.net>
To: <discussion at nsrca.org>
Sent: Monday, December 01, 2003 1:11 PM
Subject: Re: CTE


> 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
> > >
> > >
> > >
> > >
> > >
> >
> > --
> > CoreComm Webmail.
> > http://home.core.com
> >
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>


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