Van's RV-8 Build. Ep 094. Wings 23. Main spar countersinking II - That Hippie Pilot Watch in HD on YouTube! Share on Facebook! Only two hours this evening. A busy day outside of the aero factory meant only enough time to finish off countersinking the right wing spar. With any luck, I'll be able to finish off the left wing tomorrow and move on to attaching the leading edges and top main skins.