CTE

[Jeff Hughes]

Well, easier said than done! I thought I'd just measure the linear motion,
but there doesn't seem to be a reproduceable method. Probably have to go to
one of those pointer methods to scale up the motion to get an accurate
measurement.


----- Original Message -----
From: Jeff Hughes <jhughes at hsonline.net>
To: <discussion at nsrca.org>; <discussion at nsrca.org>
Sent: Monday, December 01, 2003 12:01 PM
Subject: Re: CTE


> Easy enough to check. Tonight I'll measure one click on a typical
> futaba set up. (I know it will also depends on arm orientation (servo
> motion is rotational converted to linear) and arm length). But at
> least it will be a ball park.
>
>
> > 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
> > > >
> > > > =====================================
> > > > # To be removed from this list, send a message to
> > > > # discussion-request at nsrca.org
> > > > # and put leave discussion on the first line of the body.
> > > > #
> > >
> > > =====================================
> > > # To be removed from this list, send a message to
> > > # discussion-request at nsrca.org
> > > # and put leave discussion on the first line of the body.
> > > #
> > >
> > >
> >
> >
> > =====================================
> > # To be removed from this list, send a message to
> > # discussion-request at nsrca.org
> > # and put leave discussion on the first line of the body.
> > #
> >
> >
>
> --
> CoreComm Webmail.
> http://home.core.com
>
> =====================================
> # To be removed from this list, send a message to
> # discussion-request at nsrca.org
> # and put leave discussion on the first line of the body.
> #
>
>

=====================================
# To be removed from this list, send a message to 
# discussion-request at nsrca.org
# and put leave discussion on the first line of the body.
#