Submitted by Anonymous on Mon, 12/14/1998 - 21:00 Forums: LML Archive From: Rumburg, William <wrumburg [at] cdicorp.com> Subject: Hydraulic Power Pack/Relays Date: Mon, 14 Dec 1998 16:00:38 -0500 To: 'lancair.list [at] olsusa.com' <lancair.list [at] olsusa.com> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Angier - Do NOT install your master relay in the same area as the power pack. I and many others installed their battery behind the seatback on the passenger side. Simply make a flat mounting base for the battery out of 1/4" or 3/8" honeycomb. Cut the honeycomb so that it installs horizontally (with the plane horizontal), extending from the top of the aft spar rearward to the fuselage bottom (about 12"-16" long and wide enough for the Concorde RG-25 or RG-35 battery). As usual, cut back the edges of the honeycomb and backfill with micro. Install an additional 2 ply layup on each side of the honeycomb for extra strength. Go to a marine store and buy a nylon-strap type battery hold-down. Before potting the honeycomb, install the two clamps supplied for the nylon strap (template the locations forward and aft from the battery footprint and use 3/16 area washers on the bottom of the honeycomb). Pot the honeycomb mounting base in using micro and follow up with 3 ply reinforcing layups. Install the master relay on the seatback, directly above the battery. Just make small custom brackets from 1/4" phenolic, contoured to fit the seatback. Pot them to the seatback with micro and follow up with 3 ply layups. Do not get too fancy and make a cover for it. It needs to radiate the small amount of heat it generates. One builder reported in the LNN that he burned out his master relay by doing that. There are a LOT of variations on Hydraulic power pack location. I installed mine on the aft side of the baggage bulkhead and am happy with that. I'll write more on that later. Bill Rumburg N403WR (Sonic Boom)