Sid Wood wrote: >> Ok, excellent suggestion on building the airplane to the forward end of the cg limit. Just exactly how does one do that? And still follow the plans? <<
There's an adequate page in my 1990 KR2 plans (page 114) that shows how to do the weight and balance, and an example on page 115. That defines where the correct range is, although it's an accepted fact in the KR community that the last 2" of the 8" range should be avoided (to put it diplomatically). What the plans does NOT address is how to get there, but clearly it means shifting the heavy stuff around in whatever fashion is required to put the plane in the safe range, whether pilot and fuel only or fully loaded with passenger and baggage (or whatever configurations are at the extremes of forward and aft CG). Moving the engine forward is the most obvious way to get the CG forward, and spacers under the mount, or making a new mount to accomplish the task, is the "easy" way to make large changes. To get the CG more aft (as I needed in my case), moving the battery from the firewall to somewhere like adjacent to the main spar is helpful, and it can even be put further aft of the aft spar a few bays (which is where I put my backup battery). In general, I see the engine as the rough balance, and when everything else is done, the weight and balance shows where the battery, ELT, backup battery, and other stuff needs to go. N891JF has 2" spacers between the engine mount and firewall, which was the "common knowledge" solution for the aft CG problem for the KR2. Really, the smart way to do it is build all of the airplane except the firewall forward, do a weight and balance, weigh the engine and mount, calculate where the CG of the engine needs to go, then redo the W&B to show where the mount/engine should go...shimming if necessary. We have control over this, and we know to avoid the aft end of the CG range, so arranging for a forward CG is the prudent way to go. That's what I did on N56ML as well. All of this stuff is detailed in the KR Newsletters, available at http://www.krnet.org/newsletter/. Mark Langford ML at N56ML.com http://www.n56ml.com
