I have flown a KR2 only once (owned by a guy called "Sparky" in California-Thank you Sparky- Is he still around ??) and found it very responsive especially in pitch. I could handle it easily because of my experience in light helicopters. But it is definitely more sensitive than your average plane.
I would like to own one though!!!! I wondered if using a full flying tail (sometimes referred to as a "stabilator") would cure the stability problems ? FWIW Woody --- On Thu, 5/3/12, krnet-requ...@mylist.net <krnet-requ...@mylist.net> wrote: > From: krnet-requ...@mylist.net <krnet-requ...@mylist.net> > Subject: KRnet Digest, Vol 354, Issue 122 > To: kr...@mylist.net > Date: Thursday, May 3, 2012, 9:59 AM > Send KRnet mailing list submissions > to > kr...@mylist.net > > To subscribe or unsubscribe via the World Wide Web, visit > http://mylist.net/listinfo/krnet > or, via email, send a message with subject or body 'help' > to > krnet-requ...@mylist.net > > You can reach the person managing the list at > krnet-ow...@mylist.net > > When replying, please edit your Subject line so it is more > specific > than "Re: Contents of KRnet digest..." > > > Today's Topics: > > 1. Re: VG's (Jeff Scott) > 2. Re: VG's (rdrace...@aol.com) > 3. Re: VG's (Willie van der Walt) > 4. Fw: Re: KR> VG's (joe.kr2s.buil...@juno.com) > 5. Fwd: Definitely aero core (jon > kimmel) > 6. magazine article on Aero-Core > (jon kimmel) > 7. Doubler (Gary Robison) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 02 May 2012 00:07:38 -0400 > From: "Jeff Scott" <jscott.pla...@gmx.com> > Subject: Re: KR> VG's > To: virg...@bellsouth.net,"KRnet" > <kr...@mylist.net> > Message-ID: <20120502040738.50...@gmx.com> > Content-Type: text/plain; charset="utf-8" > > I'll say it's pitch sensitive. It is also dynamically > unstable in pitch. Whether builders want to accept it or > not, the original KR-2 tail in the plans lacks sufficient > horizontal stabilizer to stabilize it in flight. The lack of > stabilizer makes it very sensitive to upset by control > inputs and dimishes the feel in the stick. It is a common > problem with home built designs but the KR is one of the > worst offenders in tail design. By anybody's measure, the KR > has an unusually small tail as compared to the wing area. > The short fuselage only exacerbates the problem. > > If this wasn't an issue, why has the forum always had > discussions about how to hold the stick with you wrist > stabilized on your leg or an armrest or something else > stable? What other plane needs that kind of a crutch to aid > the pilot in flying straight and level? > > I flew my KR with the plans built stock KR-2 tail for 500 > hours. You can learn to adapt to it. I did in about two > flights and never really had a problem flying it. But that > doesn't make it right. After 500 hours flight time I cut the > tail off my KR and built a new stabilizer using the airfoil > from Mark Langord's web site using an 8 foot span (vs the 6 > foot original span). I've flown the plane another 390 hrs > since changing the tail. The change in stability was > dramatic. The elevator is still quite light, but the > instability is gone. The larger tail in no way diminished > the sporty feel of the plane. It only made it easier to fly > and added a little bit of feel to the stick. > > As for the question about vortex generators on the tail, > they help keep the flow attached to the elevator at high > angles of attack, making it even more effective. I wouldn't > expect VGs to help address the issue as described in your > post. > > FWIW, I recently purchased and installed Vortex Generators > on my SuperCub. I didn't install them on the tail as mine > really doesn't show that it needs to be more effective even > at very high angles of attack. The VGs on the wing didn't > lower the stall speed, but did keep the flow better attached > up to the point of stall, so the plane flys much more stable > with a lot less wallowing around in slow flight (27 mph > IAS). > > OK, you can accuse me of heresy , but I don't know of > anyone else that has flight tested and flown significant > hours in their KR with two vastly different tails. Note that > I have not tested the slightly larger -2S tail. I have my > expectations of how it would fly, but since I have not > flight tested it, I won't comment. > > Jeff Scott > Los Alamos, NM > > > > ----- Original Message ----- > > Who says the the Pitch is sensitive ? Virg On 5/1/2012 4:08 > PM, Robert Boyd wrote: > Just wondering, Instead of > adding some length to my horizontal > stabilizer, would > adding some VG's to the underside of the elevator do > > anything to help with pitch sensitivity? > > > ------------------------------ > > Message: 2 > Date: Wed, 2 May 2012 01:52:18 -0400 (EDT) > From: rdrace...@aol.com > Subject: Re: KR> VG's > To: kr...@mylist.net > Message-ID: <38164.328a7826.3cd22...@aol.com> > Content-Type: text/plain; charset="US-ASCII" > > In a message dated 5/1/2012 1:09:16 P.M. Pacific Daylight > Time, > ifly...@gmail.com > writes: > > Just wondering, Instead of adding some length to my > horizontal > stabilizer, would adding some VG's to the underside of > the elevator do > anything to help with pitch sensitivity? > > _______________________________________ > Search the KRnet Archives at http://mylist.net/private/krnet/ > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > > I'm again mystified by talk of pitch sensitivity. Is > it maybe a CG > problem or something. I believe my KR is plans built, > and after 50 hours haven't > noticed any pitch sensitivity at all. It doesn't > appear to have an > incredibly long elevator. Maybe if your is too sensitive you > could build some > kind of a control damper or something for it. > > Todd Thelin > Spanaway, WA > > > ------------------------------ > > Message: 3 > Date: Wed, 2 May 2012 08:13:34 +0200 > From: "Willie van der Walt" <touri...@intekom.co.za> > Subject: Re: KR> VG's > To: "KRnet" <kr...@mylist.net> > Message-ID: > <4FA6D1B2B39146FEA31317C86100EA62@WilliePC> > Content-Type: text/plain; format=flowed; > charset="iso-8859-1"; > reply-type=original > > With the 3300 Jubiru 120hp engine, in my standard KR2, I am > on the front C > of g limit with full tank. Slight back pressure on the stick > and I find no > sensitivity. When I bring the plane to the stall the speed > bleeds down to 52 > mph and start to mush. The nose does not fall through. > Running out of > elevator control. 262mm 62% > > -----Original Message----- > From: rdrace...@aol.com > Sent: Wednesday, May 02, 2012 7:52 AM > To: kr...@mylist.net > Subject: Re: KR> VG's > > In a message dated 5/1/2012 1:09:16 P.M. Pacific Daylight > Time, > ifly...@gmail.com > writes: > > Just wondering, Instead of adding some length to my > horizontal > stabilizer, ........ > > > > > ------------------------------ > > Message: 4 > Date: Wed, 2 May 2012 16:28:24 GMT > From: "joe.kr2s.buil...@juno.com" > <joe.kr2s.buil...@juno.com> > Subject: Fw: Re: KR> VG's > To: kr...@mylist.net > Message-ID: <20120502.122824.3119...@webmail08.dca.untd.com> > Content-Type: text/plain; charset=windows-1252 > > Great job Jeff,I think his information is just about right > on. I well venture a comment about the 2s tail. While my > plane has to many changes to evaluate which makes a > difference the plane is pretty dang stable and even with a > header tank burning fuel off over the course of a couple > hours can be flown without any trim changes. The tail volume > of my plane is stock per plans. The pitch is fine and nearly > every sole that has flown with me has been able to handle it > without a problem. So I would say that the horizontal > stabilizer is adequate from the plans of a 2s, But I do not > see any harm in increasing the volume either. I would take > issue with the volume of the vertical stabilizer and rudder > of the 2s plans. After over 800 landings with some of them > in conditions that I wouldn't do if given a choice. I would > increase the the height by at least 3 inches and maybe make > the leading edge further front. I would increase the > trailing edge of the rudder by an additional 2". Just to be > clear it all works as is for all normal flying but I think > this would help the cross wind component significantly. I > also love to slip right down to the deck and it would make > this slightly more effective.Food for thought,Joe Horton > > ---------- Forwarded Message ---------- > From: "Jeff Scott" <jscott.pla...@gmx.com> > To: virg...@bellsouth.net,"KRnet" > <kr...@mylist.net> > Cc: > Subject: Re: KR> VG's > Date: Wed, 02 May 2012 00:07:38 -0400 > > I'll say it's pitch sensitive. It is also dynamically > unstable in pitch. Whether builders want to accept it or > not, the original KR-2 tail in the plans lacks sufficient > horizontal stabilizer to stabilize it in flight. The lack of > stabilizer makes it very sensitive to upset by control > inputs and dimishes the feel in the stick. It is a common > problem with home built designs but the KR is one of the > worst offenders in tail design. By anybody's measure, the KR > has an unusually small tail as compared to the wing area. > The short fuselage only exacerbates the problem. > > > ____________________________________________________________ > 53 Year Old Mom Looks 33 > The Stunning Results of Her Wrinkle Trick Has Botox Doctors > Worried > http://thirdpartyoffers.juno.com/TGL3141/4fa160f077f03eea94dst02duc > > ------------------------------ > > Message: 5 > Date: Wed, 2 May 2012 12:23:51 -0500 > From: jon kimmel <jkimme...@gmail.com> > Subject: KR> Fwd: Definitely aero core > To: "kr...@mylist.net" > <kr...@mylist.net> > Message-ID: > > <CAFoZr_paSnO=nqrmtqfuod-fod3hjv6rc7jboigwzzn2mix...@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > ---------- Forwarded message ---------- > From: "jon kimmel" <jkimme...@gmail.com> > Date: May 2, 2012 12:17 PM > Subject: Definitely aero core > To: <kr...@mylist.net> > > I had to switch my account...looks like the recent spam > discussion may have > caused my isp to shut krnet out. > > For those who were interested in my fuselage question, the > article in > contact magazine issue 19 described the building process > exactly...including details about temporarily screwing the > strips to > temporary formers. I have permission from the editor > of contact to copy > the article and post it...although I haven't quite figured > how to do that > on the google site I was using (where's a ten year old kid > when you need > one). > > The aero core article was written in 1994 my fuselage was > built in 1999. > There was a balsa wood shortage around that time that forced > us to find an > alternate material for floor boards on the E-3...I wonder if > aero-core fell > victim to that shortage. > > If you are interested in the article before figure out how > to post it, > e-mail me directly at kimm...@cox.net. > > > ------------------------------ > > Message: 6 > Date: Wed, 2 May 2012 20:29:34 -0500 > From: jon kimmel <jkimme...@gmail.com> > Subject: KR> magazine article on Aero-Core > To: kr...@mylist.net > Message-ID: > > <CAFoZr_rsm4VWWmhBp0Cf56W9XD87ZvM37GHxJUe=j+y8txb...@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > I think I have it published now. My son used to do > this for me...you can't > keep them home forever. > > https://sites.google.com/site/mykr2stretch/ > > Jon Kimmel > kimm...@cox.net > > > ------------------------------ > > Message: 7 > Date: Wed, 02 May 2012 23:38:38 -0400 > From: "Gary Robison" <djgaryl...@verizon.net> > Subject: KR> Doubler > To: "KRnet" <kr...@mylist.net> > Message-ID: <FF128BF9A7BC4F29A6CE8F315DE29B98@GLR100> > Content-Type: text/plain; format=flowed; > charset=iso-8859-1; > reply-type=original > > The upper longeron forward doubler did you > glue it in before or after making the fuselage bend > > Just trying to make things easier > > Gary > > > > ------------------------------ > > _______________________________________________ > See KRnet list details at http://www.krnet.org/instructions.html > > End of KRnet Digest, Vol 354, Issue 122 > *************************************** >
