<br><font size=2 face="sans-serif">Nat</font>
<br>
<br><font size=2 face="sans-serif">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. </font>
<br>
<br><font size=2 face="sans-serif">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.<br>
<br>
<br>
<br>
Gray Fowler<br>
Principal Chemical Engineer<br>
Composites Engineering</font>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td>
<td><font size=1 face="sans-serif"><b>"Nat Penton" <natpenton@centurytel.net></b></font>
<br><font size=1 face="sans-serif">Sent by: discussion-request@nsrca.org</font>
<p><font size=1 face="sans-serif">11/24/2003 09:24 PM</font>
<br><font size=1 face="sans-serif">Please respond to discussion</font>
<br>
<td><font size=1 face="Arial"> </font>
<br><font size=1 face="sans-serif"> To: <discussion@nsrca.org></font>
<br><font size=1 face="sans-serif"> cc: </font>
<br><font size=1 face="sans-serif"> Subject: CTE</font></table>
<br>
<br>
<br><font size=2 face="Arial">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</font>
<br><font size=3 face="Times New Roman"> </font>
<br><font size=3 face="Times New Roman"> </font>
<br><font size=3 face="Times New Roman"> </font>
<br>
<br>