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Building Tail Ribs

Posted: Thu Nov 19, 2020 12:37 am
by wleferrand
Dear all,

Fair warning: I have 0 experience with wood construction.

My first goal for our Falco project is to build a jig that would allow an 8 year old to assemble the stabilizer rib at station 0.

I'm thinking of carving this jig in plastic or wood with a CNC: https://a360.co/2UHscdH (the web sharing tool is a bit crude but there is a backplate behind the drawing)

The bottom part of the jib will allow her to slide a 5x10 spruce stock, then cut the braces at the right length and with the right curves at the end. Then the top part of the jig will allow for the rib assembly, by cutting the capstrips on both ends then glueing capstrips with the braces.

Is there anything obviously wrong with this approach?

Thanks in advance for your insights!

william

Building Tail Ribs

Posted: Tue Nov 24, 2020 10:33 pm
by wleferrand
I got some quotes from local shops to cut up the jigs and it's not going to fly. Around 100e apiece. Maybe the first project will be to set up a CNC.

Building Tail Ribs

Posted: Fri Dec 04, 2020 12:21 pm
by wleferrand
I ended up joining the local fablab. Their capabilities are limited (no router / milling machine) but they have a laser cut. They only had cardboard handy so I did a trial cut in cardboard; I'm not sure about the tolerances but the Falco manual calls for 0.1mm anyways.

Apparently we can't attach pictures to the messages?

Building Tail Ribs

Posted: Sat Dec 12, 2020 5:17 pm
by wleferrand
It turned out that the CNC laser cutting machine at the fablab has unacceptable tolerances on one axis. They are about to put another one in service, it is already on the shop floor but it is missing the air filtering plumbing.

In the meantime, I re-drew the jig so that it can be used to both cut the capstrips/braces and glue them at the right place. Gussets will be laser cut. Can't wait to try it out and see how the rib building process goes.

Cheers
william

Building Tail Ribs

Posted: Thu Dec 17, 2020 5:30 am
by pete
The rib jigs don’t have to be very durable — you only need to make 2 ribs out of each jig. And when you assemble them all, you float sand the ribs to final shape before skinning it. So absolute perfection is not absolutely required. Don’t be afraid to make a bad rib and throw it away. The second or third one will turn out fine and then so will the rest.

Cheers,
Pete