I'm not building an 8 (long story but it involves RV4 wings) but I have a question, please. All of the Vans construction/drawings I've seen has a similar design philosophy; spars spliced together in a "box beam" type center section. So, my basic assumption would be the spar length is 1/2 the air frame span minus the wing tips (plus the ~ 1" of spar extension for construction). My assumption was you'd round to 23'/2 - ~8' (depending on wingtip), so just over 10.5 feet. Where's the missing length? What am I assuming wrong? Your knowledge is appreciated. My apologies to the OP for any thread hijack. Trying to get smarter here. Thanks