As many of you know, I had the original KR-2 tail on my KR, then cut it off and built a significantly larger tail.? ? For some background, the boat for my KR was constructed prior to the release of the -2S plans.? It was becoming common at that time to extend the fuselage, so mine has a 14" extension (one bay) added to the aft fuselage as compared to a stock KR-2.? Otherwise, the fuselage matches the KR-2 plans.? I flew the plane for 500 hrs with the small 6' tail plane built according to the original plans.? Then I cut the tail off and used the plans provided by Mark for the 0009 tail airfoil, and built it to an 8' span.? Invariably when I talk about how much of an improvement this made to the handling, I apparently must be calling others babies ugly, so end up getting a lot of disparaging remarks about my piloting skills or lack there of.? Of course those that seem to think this is a poor modification have never flown a KR with an 8' span tail.? My description is that it is still just as sporty, and still quite light to the touch, but it has significantly better stability in pitch in that a large individual my size can reposition in the plane without creating an aerobatic experience.? The plane flies very nicely hands off.? While the elevator loads up a bit at speed (which I would not describe as heavy by any means), which actually helps to keep one from over-controlling, it also has a good solid feel even at very slow speeds.? The elevator is still light as compared to a Sonex or RV, but is much closer to that kind of feel than the original tail. ? I did not enlarge the vertical stab, but instead added some additional area by extending the cord of the rudder by an average 2-1/2"? That change significantly increased the rudder authority.? If I was doing it again, I would have also increased the height of the vertical stab and rudder and cord of the vertical stab at least to match the -2S plans, but using the 0009 airfoil.
With the changes to the elevator and rudder, the slow speed handling of the plane was significantly improved allowing me to significantly increase the manageable crosswind and gust factors for landing, so I get to fly my plane a lot more than I was able to before these mods. ? I don't have the dimensions of the fuselage available, but if you have the KR-2 plans, it's easy enough to derive.? I did not extend the front fuselage, but instead used a bit longer motor mount than was customary at the time to move the engine (originally a C-85, then an O-200) forward to balance the aircraft.? A number of KR builders have built their engine mounts from the plans I shared with the group. ? -Jeff Scott Los Alamos, NM Lots of info on the mods I've done at <http://jeffsplanes.com> -------------------? Morning Folks, ?? I would like some more dimensions for the length of existing KR2 and KR2S fuselages, (foreword face of main spar to back side of firewall and foreword face of main spar to the intersection point of the tail post to fuselage bottom) I have about 10 so far but I would like to get 3 or 4 times that many to have a decent data base. ( I would like to hear from more of the overseas guys... I'm pretty sure I can figure out how to covert to/from meters) ?? The conversation below brings out the same dimensional issue as I am trying to document with the fuselage .... when adding what is the total dimension. I don't have plans in front of me but are we talking about 5 feet wide, 6 feet, or even 7 feet I had mentioned it a few weeks ago with the vertical stab... when adding height what is ?that from and to. I mentioned at that time for the vertical it might be better to talk in sq. feet. ?? Please send any data to n357cj at ptd.net ?I would like to get this out posted with inn a month allowing to get as much feed back as I can. Thanks, Joe Horton ----- Original Message ----- From: "Mark Langford via KRnet" <krnet at list.krnet.org> Joe Nunley wrote: >> How much carbon fiber is enough? I built a 6 inch extension to my tail surface the way that Mark describe below. When I attach the new addition to the airplane I will t88 glue it to the tail and cover in carbon fiber. I want o overlap the old and new with carbon fiber. How far do I want to overlap? << I would have built the extension in place, as a piece of foam glued to the end, shaped using the existing airfoil, and then carbon-fibered in place, overlapping the existing stabilizer (after sanding to expose raw fiberglass) by something like 3"-4". ?T-88 isn't the first epoxy I'd have thought of for that job (the way I describe above), but given that it's already built, T-88 should work fine, as its thickness would help ensure all surfaces are in good contact. ?Rough it all up to ensure lots of "tooth", of course. Mark Langford ___ _______________________________________________ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html[http://www.krnet.org/info.html] see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org[http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org] to change options -------------- next part -------------- A non-text attachment was scrubbed... Name: Jeffs KR.jpg Type: image/jpeg Size: 29200 bytes Desc: not available URL: <http://list.krnet.org/mailman/private/krnet_list.krnet.org/attachments/20160217/7fd06358/attachment.jpg>
