Saturday, May 4, 2013

Beautiful spring day for a Goat

I'm sitting outside on the porch looking over an amazing sight: the first time Dan's Goat has been assembled with the wings on.


Now I started down the path of a cable-braced wing and will be switching to using wing struts, so use your imagination to remove many of the temporary lines.  However, this is the first time I have the big-picture view of sitting in the pilot's seat and looking down the length of the wings above me.  Such a cool sight.

During assembly, there were a few lessons learned already.  Handling the wings is a challenge at this stage, with a lot of flexing and wobbling to move them into position.  I know with covering on they'll get more torsionally rigid, so there's no cause for concern, just noting an 18ft by 4ft panel is big to move around.  The LE and TE pins aren't too tough to align and install.


Next is the fuselage attachment.  This involves awkwardly standing the fuselage on the tail, pinning the LE tube, then moving the fuse into place for pinning the cabanes.  Now on the strutted version this will be different, but no doubt it's going to be a magic step.  I also definitely need a piece of carpet or something to toss on the ground and keep the tip of the fuselage from poking into the dirt.


Rotating the fuselage and wings up is going to be a lot easier with rigid struts.  Using some 150lb test cord I had laying around, I rigged up the kingpost and flying wires.  It definitely took pulling a lot more tension in the upper lines than I initially thought to keep the wing with positive dihedral.  There is a lot of stretch in my thin lines.  But once the wing and fuselage are triangulated together, they rotate up as a unit just fine by pulling on the nose to rotate everything up onto the wheel.


Since it's so nice outside, I had to attach the tail as well.  This too is a little awkward as the fuselage attach point is leaned a little so the vertical tail assembly needs to be rotated as well.  Attach the lower pin first, then the upper pin, not too tough.  The horizontal stabilizer is a piece of cake from there.  Then connecting all the control cables is quick and painless.  Viola, Goat!


What else can I say?  It's coming together.  This feels like I've crossed the half-way point.  Structurally, I have the struts, their respective attach points, and the jury struts remaining.  Then it's all secondary structure for the wing: lots of ribs, wing tips, control surfaces, hinging, control rigging, and d-tube sheeting.


Oh I also weighed the current structure while assembled: 62.8 + 6.8 + 17.2 = 86.8lb  This doesn't represent any particular reference state, but does give me a warm-fuzzy that there is 60-something pounds to stay in the Part 104 glider class.  The struts aren't light and there is a lot of aluminum in the ribs and control surfaces to go.  Then covering / paint.  Fingers crossed guys.

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