Kelvin, one way to get your datum line is to use a lazer leveling device that lights a horizontal beam. Shim your fuse accordingly and when happy with the alignment, mark the red line with a semi-perm marker.
Getting the horizontal ref line on the money will determine to a large extent whether your model needs any pitch mix in knife edge flight so its a good idea to get the line as close as you can.
I didn't do it that way tho since it is a little cumbersome, even with a lazer level. I have outlined what I did with the one I have set up in an earlier page of this thread, so I won't write that again.
MattK
ORIGINAL: KRitchie
Hello,
I'm building an Impact for a friend. It's going to be an electric conversion using a Hacker C50. I've built about 11 models over the last 3 years but this is my first pattern and composite model.
I've got the instructions downloaded from the C-ARF website and have been following them pretty much accept for the anti-rotation pins for the wing. I'm using the 12mm short tubes as the pins and not using the long 10mm diameter tube illustrated. Jason Shulman does this with his Impact. The reason I did that is my hardware kit didn't have the correct parts in it. I was missing the 12mm CF stab spar tube and the stab spar tube wasn't a tube but a solid CF rod and it was about .7 ounce. The wing anti-rotation 10mm tube was another 10mm solid rod weighing about .7oz. When C-ARF sent me the new parts, it took over a month after I was notified they were shipping to reach me, the wing anti-rotation pin tube was not included and I didn't want to wait another month for the part.
I've installed the cowl, the landing gear formers and struts, the tail stab former reinforcement and mounted and epoxied the wing tube an stab tubes
I'm documenting my build on EZone at
http://www.rcgroups.com/forums/showthread.php?t=305894
I'm confused where the datum line is. The instructions state 37mm down from the center of the stab tube yet the build thread on the C-ARF UK site says its 30mm.
OK, time for a stupid question. How are you guys drawing a straight line on the masking tape from the cowl joint all the way back to the tail? I've only got a 10 foot metal tape and a 3 foot metal yardstick. I was thinking of getting out my chalk line and seeing if I could lay a temporary line and then make some permanent marks.
Thanks for any help.
Kelvin