Decided tjo install a NACA duct for cockpit cooling in right panel behind firewall. Using some tracing paper, I traced the inside opening.I transfered this to stock paper and then to the sheet metal. I carefully cut access holes so that I could use a nibbler. Once the rough opening was made, I started filing to make the openings match. I drilled and counterunk the sheet metal to accept the rivets to attach. Using 3m structural adhesive, I joined the two halves of the duct with soft rivets and allowed the adhesive cure. I then cut the duct outlet to match a 2" aluminum 'Y" to provide cooling air to both seats.
