KRNetters I am in the process of determining the cg on my project. In comparing cg location, RR plans show the 8" cg range with the fwd edge of the range starting 8" aft of the leading edge of the wing. Based on the profile of the 48" rib, the leading edge of the cg range is 2" fwd of the front face of the main spar. I have Diehl RAF - 48 skins along with inboard skins that Jeannette Rand also produced. With those, the leading edge of the wing is 11.5" fwd of the front spar face, an 1.5" fwd of RR plans. Should I move the cg envelope fwd by that 1.5" or use the cg range set by RR. Next question: Preliminary calculations show my empty cg is approx. an 1" fwd of the RR cg location. Knowing that any weight added, passengers, fuel, baggage, etc will fall push the flying cg aft, should I fabricate my engine mount using this calculated engine position? I have done calculations with pilot plus 1/2 fuel and it falls at 2" into the RR cg range, and pilot & passenger plus 3/4 fuel and cg falls within 6" preferred cg range, the later coming in right at the aft edge of the preferred range. I'm thinking that I would like set the engine such that with me and 1/2 fuel that the cg falls right at the fwd cg limit.
Next question: The horizontal engine centerline with the temporary engine mount is 2.5" below the top of the upper longerons. I'd like to drop the centerline a little more, 1/2 to 3/4", for better clearance for engine cowling and cooling plenum. Anyone see a problem with that. All advise cheerfully accepted, Thanks in advance for any and all assistance. Pete Klapp
