My Sonex spars took about 120 hours to complete, with about 20 of those hours being required to drill and re-rivet a bunch of the spar as I put the factory rivet heads on the wrong side of the spar-web (d'oh)! I would imagine that the Xenos spars - if built without mistakes that require re-work - would also take about this long. So consider the value of your time and how long you think it'll take you to build the plane, and then go from there. For the record, when I bought my Sonex plans in 2009 I thought my plane would fly in 2012. Then I started flying sailplanes a lot in the summer months, then I got engaged, then I got a promotion at work; and now its looking like it'll be late 2015 or early 2016 - if I'm lucky! But the point is: its not unreasonable that 100 hours of labor could be roughly a year you add/subtract to your build time.
As for the machined angle components: DO IT!!!
I started out scratch-building my Sonex, and began by buying a bunch of aluminum angle. I put about 50 hours into learning how to shape and refine the various angle components; and started feeling realllly good about what I was making. Then my work-life got busier and it became clear that I needed to get the kit if I was going to finish the plane. I bought the tail sub-kit, which comes with machined angle components. WOW, the difference between my "good" hand-shaped parts and the CNC-made parts was incredible. When placed side-by-side, my stuff looked like crap! On the one hand, it was a bit disheartening. But watching everything line up nicely and having lots of pilot-holes to work with was really awesome. It immediately convinced me of the value of the machined angle components. I went ahead and bought the rest of the Sonex kit with these components, and have never regretted it for an instant! Initially I thought I'd use a few of my hand-crafted parts anyways - just to honor the labor I'd put in, and the spirit of homebuilding. But the CNC parts are just so darned perfect that I haven't been able to bring myself to use a single one of the pieces I made! I've got a whole box of them still sitting quietly (and sadly) in the corner of the garage.
That's my $0.02,
--Noel Wade
Sonex #1339
Center-stick, TD, Turbo Aerovee, Acro-aileronsBuild time:
467 hours (tail complete, wings near-complete)