[WWI] Added:Rumpler C.I

[Paul Thompson]

>Aaiiieee Paul!
    You got me scared now!  Can you describe how you rigged it? and
what, in your opinion, might be wrong ?
Is it the resin ? the rigging material ?
I havent rigged my 6B1 yet, so it might not be too late to learn from 
mistakes.
regards
Sanjeev
<

Apologies. Verbose mode engaging.

. Same as with the CSM Gotha, I decided to avoided drooping wings by having 
fixed points (for the Gotha this was the struts on the engine nacelles, and 
the central cabane inverted vees, made of Strutz. For the Rumpler this had 
to be the central cabane vees, again of Strutz). The idea is to rig firmly 
in all the other positions, but have extra tension on the wires from the top 
of the fixed points to the bottom of the next bay's struts. The struts are 
then held up so that the top wing won't sag, and pulled up so that the 
bottom wing won't sag. For this to work requires enough space that you can 
tension everything at the same time and in the same direction before gluing 
up. So in this case the wires were first fixed to the firrings supplied by 
CSM, then these were fixed to the struts as they were glued in place. A few 
had to go into the fuselage instead. The struts were held in place by a jig 
while they dried in the correct poitions, with the top wing fitted but not 
glued. Then I inverted the lot, set it up with constant dihedral along each 
wing, threaded the rigging through the top wing strut holes, secured with 
thin superglue, then filled in from the top with thick superglue and sanded 
off. After a days drying I turned it the right way up and all was fine. The 
next day it was loose. I thought the glue hadn't grabbed the cables, but 
later in the day it was all tight again.

The weather the last few days has had huge changes in humidity and 20 C 
range in temperature. I think the combo is the problem, added to the basic 
flexibility of the resin. The cure (Sanjeev) would be to use ceramic rod for 
the rigging. This has held up fine with the Gotha, even though the weights 
involved are greater. The invisible thread used on the Rumpler is clearly 
not up to the task when used this way, although on the camel I made for IM, 
which has been in the same room all the time, there is no problem. This is 
probably because the runs are shorter and the tension much less. If your 6BI 
is already rigid enough, I don't think there will be a problem, whatever you 
use.


HTH,            Paul T.