What Chris describes is not at all unusual. A number of aircraft fly better in an aft CG as the elevator gets too heavy with a forward CG. A C-182 is a good example. A 200 horse Muskateer is another. It flies better and is easier to land if your CG is a bit aft simply because the elevator gets so heavy during landing when the CG is forward even though both configurations are still within the acceptable CG range. Flying with a forward CG in these planes requires so much aft trim that the down force on the tail and trim drag is enough that the plane flies slower in a forward CG.
The stock KR has so little stabilizer that an aft CG configuration can get very pitchy. I flew my KR with the small tail for 500 hours before cutting it off and building a larger tail. I've flown it another 650 hours since with the larger tail, so I think I can comment on this from a position of first hand experience. After building a larger horizontal stabilizer and elevator, I really don't notice much difference in handling between a forward and aft CG in my KR as long as I stay within the 6" CG range as recommended by most builders. I built the new stab and elevator to an 8' span using the templates Mark provides on his web site. -Jeff Scott Los Alamos, NM ------------------------------- > Could you go into further detail about "how" it flew better with a forward > CG than an aft CG? Sure, the plane under normal conditions (no baggage) would require significant up trim to unload the stick, and when pulling power, would drop the nose unless you held onto the stick. "Lawn dart"is a description used more than once. Conversely, with plenty of stuff in the baggage compartment (at or near aft CG limit), the plane seemed to "float" in balance and handled much better and was faster to boot. A pure dream to fly. This was discussed often. It was considered by some to be good practice to ignore the front half of the CG envelope. It is possible that the CG envelope was shifted a bit forward than it should have been and in fact I spoke with someone in good authority that the aft limit was quite conservative and flying AT the published aft limit would in fact produce good results, and it did. > See http://www.n56ml.com/wb/index.html for more on the KR aft CG, which I'm > pretty sure is common to most aircraft. This story should scare you...it > certainly scared me! I actually had read that last year, another well written piece and in fact I am sure I saved it to PDF as well in my KR own knowlege base. _______________________________________________ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org