Aatually, I have exactly the same question on checking and verifying the weight & balance on my KR2... Is it right underneath the main spar of the wings, or 3 to 4 inches position from the leading edge going backward? The reason I think it's the CG spot because I used two jacks and lifted the whole thing (at empty weight, of course), and found the whole aircraft could stay balanced along the lateral axis...
Of course we can calculate the CG point if given design information, but I suspect that the ultimate verification of CG is to use 3 weight scales (one on each wheel) to find out the weight balance (empty or gross) point perhaps. Am I correct? Also, I wish to know what's the design error tolerance on the CG position for KR (not KR2S)? Such tolerance is determined by the capacity (surface area) of the stabilizer, correct? If there is any uncertainty about the CG spot, or to put the last two ponds of extra luggage during loading, we would much prefer to allow the tail heavier than otherwise, true or false? Kindly, Dr. Hsu On Sun, Aug 9, 2020, 10:50 AM Anthony Steinke via KRnet < krnet@list.krnet.org> wrote: > Hi Sam, thanks so much for taking the time to welcome me and give me all > that information! Do you have any suggestions on where to start when > figuring out weight and balance and have you had to rebuild the heads on > your engine often? I plan on reading through the archives between now and > spring and re-reading Mark's content. Thanks again for the huge welcome and > if I ever do make it out your way I'll be sure to let you know! > > Anthony Steinke > > Get Outlook for Android<https://aka.ms/ghei36> > > ________________________________ > From: KRnet <krnet-boun...@list.krnet.org> on behalf of Samuel Spanovich > via KRnet <krnet@list.krnet.org> > Sent: Sunday, August 9, 2020 12:05:44 AM > To: krnet@list.krnet.org <krnet@list.krnet.org> > Cc: Samuel Spanovich <spanovich...@gmail.com> > Subject: KR> New Guy > > Hey there Anthony, and welcome to the KR world! If you’re looking for a > plane that is cost effective, efficient, fast, and pretty reliable for the > most part (more of a function of the builder/engine), you could not find a > better airplane. You’ll find that most “stock” KR-2S’s can do about 120-130 > mph in cruise with a 65-70HP VW motor, at about 4-5 gallons per hour. > These are way better figures than you’ll get out of a Cessna 150/152 and > about on par (if not slightly better) than a Cessna 172/PA-28 series. If > you consider a KR-2S with a Corvair, or even an O-200, forget it, there is > no comparison there; you’ll be looking at a 160-170mph airplane. > > For gross weight considerations; this is mainly just a factor of who > builds and signs off on the plane. Since it’s experimental, the builder can > set the gross weight they desire. My KR weighs ~650 lbs empty, with a gross > weight of 1150, and holds 12 gallons of fuel; this gives me a payload of > about 430 lbs, which is good for me and my wife and a carry on bag of > luggage if we take a XC somewhere. I’ve heard of some builders set their > gross weight to 980 lbs, and some as high as 1200 lbs. > > On the other hand, while the gross weight is fairly forgiving, the center > of gravity is not. If you do purchase a KR, make sure you know EXACTLY (and > I mean exactly) where the center of gravity is when empty, and when full. > When you start getting into the aft 2” of the CG envelope, the plane gets > very squirrels, and even the most skilled pilots have trouble in this > configuration. I won’t elaborate too much right now, but CG is very > important in this airplane. Mark Langford has several terrific articles on > this subject (and virtually everything else as well). > > But assuming you have done everything correctly (which I have no doubt you > will), once you are up in the air, oh this plane is so fun to fly. While it > is not really a true “hands off” airplane (when compared to a > Cessna/Piper), it does fly very smooth In calm air. It doesn’t take > turbulence too well, since it is so light and the wing loading is fairly > minimal, but if you’re like me and are an adrenaline junkie, I love the > roller coaster ride! In regard to roll/pitch, the controls I feel are > crisp, but not too sensitive. The bubble canopy, and the crisp controls > also almost give the feel of a small tactical jet, just not nearly as fast, > which is unfortunate. > > You could find nearly a million engine choices for this airframe, but the > two most common seem to be Volkswagen variants (Revmaster, and Great > Plains), and Corvair 6 cylinder engines. Long story short, both are great > choices and there is a lot of information on this forum regarding both > engines. I am running a Revmaster 2100D with electronic ignition, 94mm > cylinders, and a CB2232 Camshaft. It produces about 80HP. > > You could write an entire novel about these airplanes given enough time, > so I’ll stop here for now, but please feel free to reach out to myself, or > virtually any other person on here if you want more info; we’re always > eager to discuss our airplanes! Good luck in your search for an airplane! > The KR is a solid choice! > > Lastly, I’m a bit far from Minnesota, but if you ever find yourself out in > Washington, please let me know when/where and I can show you my airplane! > > V/R > > Sam Spanovich > N6399U > 74S, Anacortes WA > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/krnet@list.krnet.org/. > 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 > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/krnet@list.krnet.org/. > 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 > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. 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
