From: krnet-bounces+johnbou=speakeasy.net@mylist.net on behalf of krnet-request@mylist.net Sent: Saturday, December 20, 2003 12:00 PM To: krnet@mylist.net Subject: KRnet Digest, Vol 255, Issue 2 Send KRnet mailing list submissions to krnet@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-request@mylist.net You can reach the person managing the list at krnet-owner@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: KR Information (Mark Langford) 2. Re: airfoil design (Mark Langford) 3. Re: airfoil design (lloyd schultz) 4. RE: Calendar (Jack Cooper) 5. Re: airfoil design (Mark Langford) 6. Re: airfoil design (Dana Overall) 7. I've learned a lot! (Thomas Brock) 8. Why trailer a KR? (Thomas Brock) 9. Re: Why trailer a KR? (larry severson) ---------------------------------------------------------------------- Date: Sat, 20 Dec 2003 10:46:23 -0600 From: "Mark Langford" To: "KRnet" Subject: Re: KR>KR Information Message-ID: <0ce501c3c718$cd6f1ea0$1202a8c0@basement> References: <37.423bc220.2d1570d2@wmconnect.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 1 Larry Husky wrote: > I am new to this group and would love to have some information about > the KR. > I am wondering if there is any way to up the gross weight. Bigger > engine, extra spars. I am wanting to use a direct drive EA81 engine > for my power plant. > I really like the KR but need a little more gross weight. Any information > would be great I would suggest visiting the KRnet archive at http://www.maddyhome.com/krsrch/index.jsp and keying in "gross weight" into the search box. You'll find 472 messages that will probably answer your question a lot quicker than waiting on a reply here. You'll also learn a whole lot about KRs in a hurry. Check on Subarus too, and I think you'll find the Corvair a better alternative... Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ------------------------------ Date: Sat, 20 Dec 2003 10:54:46 -0600 From: "Mark Langford" To: "KRnet" Subject: Re: KR>airfoil design Message-ID: <0cf301c3c719$f974d840$1202a8c0@basement> References: <8539000.1071930367305.JavaMail.root@bigbird.psp.pas.earthlink.net><004701c3c70a$92d8d4b0$1202a8c0@basement> <3FE47B75.E1D730BA@earthlink.net> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 2 Lloyd Schultz wrote: > of the most docile airplanes out there. I can't help thinking that > making a > "sweet"-flying wing is like baking a really good pastry...it's as much > a result > of the chef's ability as the vitals used. No? I knew somebody would make this point. The aircraft factories that used this airfoil had a lot more expertise in taming aerodynamic problems than the guy who asked the question. I get the impression that anybody asking for airfoil advice probably isn't going to be a "chef" with a lot of ability. Now if he wants to learn all the tricks of the aero engineering trade, he's welcome to do it. He asked for opinions, I gave mine. He can do whatever he wants, but I can't fathom why anybody would want to reengineer the KR wing when one of the world's sharpest wing specialists has already designed one especially for this airplane, with reduced drag and increased speed one of the top priorities, while maintaining the docile stall characteristics of the stock RAF48. Just my opinion though... Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ------------------------------ Date: Sat, 20 Dec 2003 10:01:59 -0700 From: lloyd schultz To: KRnet Subject: Re: KR>airfoil design Message-ID: <3FE48087.77D16FC0@earthlink.net> References: <8539000.1071930367305.JavaMail.root@bigbird.psp.pas.earthlink.net> <004701c3c70a$92d8d4b0$1202a8c0@basement> Content-Type: text/plain; charset=us-ascii MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 3 Mark- After thinking about your post, I'm compelled to comment further. Understand going in that I'm as amateur as one can be, so I don't know what I'm talking about: It was mentioned that Roy Marsh's son is an aero engineer and chose 23012 for Roy's PURPOSE-BUILT KR2S speedster. The magazine article that so featured that airplane several years ago, stated clearly that Roy built it to win a specific race. If that's true, let's consider what things his son might have done vs stock, toward winning the race. 1. Clip the wing span to reduce wing area and increase wing loading...clip the exact amount that will result in the lowest total drag at low altitude at design speed. The article said Roy clipped his wings from those of a stock KR2S. 2.Choose a different airfoil from the stock one. My copy of THEORY OF WING SECTIONS is back home and I'm not, but I believe I remember that 23012 has a very small twisting moment, such that when Roy flew full tilt, his horizontal tail would have to lift downward very minimally. 23012 is also thinner. 23012, like the RAF family is turbulent, so good results were had from wood-and-composite constuction. Result of all this is lower total drag at design speed. 3. Retain the KR2 planform, or the KR2S planform. Again, I don't have the URL for the site, but the U of Ill sight showing posted data by Selig has a spot where Ashok's airfoil is discussed. Somewhere in a thread from that, I found Ashok discussing the stock planform. Planform can do much to reduce drag. Turns out the stock KR2 planform is about as near-perfect as a rectangular-with-tapered-tips can come vs optimal. Lower drag at design speed. 4. DON'T BUILD IN AS MUCH GEOMETRIC TWIST...aka washout...as you would for a plane you intended to fly regularly for enjoyable (aka "safe") sport. The safest amount of twists reduces the efficiency of the wing, because the roots are working harder than the tips...this is why the roots stall first, and because the tips stall later, you retain aileron control during stalls. Take twist out to the point the entire wing stalls all-at-once and you have a wing working equally tip-to-tip. Net result is lower total drag at design speed. 5. Turbocharge the thing so you can pull more-than-stock power yet remain within the rules?@#$%? More power is as good as less drag. Now, if all that was accomplished and the airframe were built very light, we'd expect an unusually fast machine at low altitudes that would stall the entire wing at once on every landing. And of course, once we'd set the record or won the race, we'd sell it. Or simply build another wing tailored for sport flying...like the stock KR2S using one or two of Ashok's new airfoils. I remind you, this is just conjecture on my part...I don't know what I'm talking about. -Lloyd Mark Langford wrote: > Bob Tallini wrote: > > >>The design I would like to use is the one Roy Marsh developed for > >>the KR2S > prototype. It is a modified NACA 230012. << > > Bob, I just plain wouldn't use a 23012, no matter how modified it was. > Although it was used on everything from Cherokees to Bonanzas, the > stall characteristic is not something you want to intentionally build > into any new aircraft. Visit > http://home.hiwaay.net/~langford/23012.gif and notice how the wing > stalls very abruptly. It goes from flying to stalled almost instantly > (the "cliff-like" plot on the left). I believe Roy once told me he > had to land at about 80 mph, and that doesn't surprise me. Why not > use an airfoil that was designed specifically for the KR2S by modern > methods with one of the design goals being a reasonable stall speed > and gentle stall characteristic (gradual). If you haven't seen it, > visit http://www.krnet.org/as504x/ for the details, and check the same > curves. You'll see something a lot more gentle. > > Making the spar thinner will give you problems with gear mounting, > wing tank capacity will be significantly reduced, and you have the > strength problem (weight will go up) that you're now faced with. Yes, > Roy did it, but Roy also sold his plane after a few short years. Ron > Lee bought it, flew a few times, and sold it quickly. Not sure if > anybody's flying it now, but I'm not convinced you really want to > replicate that wing. > > Funny thing about that plane is that it's the "poster child" for RR's > KR2S advertisements, although the wing is a completely different > animal than the plans call for. > > If you really want to do this, I've temporarily posted some > "shareware" software that will do that analysis for you at > http://home.hiwaay.net/~langford/spar.zip . Plug in the dimensions > and characteristics for a stock wing, then plug in the dimensions for > yours, and then tweak caps and plywood dimensions until you get > strength numbers the same or better than stock. This is just an > approximation, as there are fine points of plywood layers and such > that probably enter into it, but it's a good "ballpark" method of > making sure you don't do anything stupid. > > Still, I wouldn't touch that airfoil with a ten foot pole. You > mention this airfoil to an aerodynamicist, and he'll start shaking his > head. Yes, I know Roy's son is an aero engineer, and he specified > this airfoil, but he didn't have the AS504x airfoil at his disposal, > and he didn't have to fly it... > > Mark Langford, Huntsville, AL > N56ML "at" hiwaay.net > see KR2S project at http://home.hiwaay.net/~langford > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html ------------------------------ Date: Sat, 20 Dec 2003 12:27:06 -0500 From: "Jack Cooper" To: "KRnet" Subject: RE: KR>Calendar Message-ID: <410-22003126201727610@earthlink.net> Content-Type: text/plain; charset=US-ASCII MIME-Version: 1.0 Precedence: list Message: 4 I would like one. Let me know when and how much. Robert J. (Jack) Cooper kr2cooper@earthlink.net http://www.jackandsandycooper.com/kr2.html Why Wait? Move to EarthLink. > [Original Message] > From: Steve and Lori McGee > To: > Date: 12/19/03 7:36:10 PM > Subject: KR>Calendar > > For those that have sent pics - thank you! > BUT WE NEED MORE! > Also there has not been a huge response, so if you are inclined to get one let me know if you haven't already. > > Steve McGee > Endeavor Wi. USA > Building a KR2S widened. > lmcgee@maqs.net > > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html ------------------------------ Date: Sat, 20 Dec 2003 12:16:18 -0600 From: "Mark Langford" To: "KRnet" Subject: Re: KR>airfoil design Message-ID: <0d0101c3c725$5d701610$1202a8c0@basement> References: <8539000.1071930367305.JavaMail.root@bigbird.psp.pas.earthlink.net><004701c3c70a$92d8d4b0$1202a8c0@basement> <3FE48087.77D16FC0@earthlink.net> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 5 I think you just finished saying the same thing I did. It's probably not going to have a pleasant stall characteristic, and if you tune that out through other geometry changes, you'll be throwing away the speed. He's free to build it as he sees fit, but I hope it sees more time in the air than Roy's has seen. Roy is an ex-fighter pilot, and used to fly P-38s, among others, and he could apparently handle it (although I'd question that given that I saw a landing at Covington up-close and personal that was spectacular in the wrong way). I'm just trying to keep somebody from making what I consider to be a mistake. I didn't come up with this opinion on my own. I mentioned the 23012 to Lionheart designer Larry French about 10 years ago and he laughed and said "you'd have to be crazy to use that thing", and I've heard it echoed several times from other sources over the years. I'm not an aerodynamicist, but I'm smart enough to listen when one talks. I guess at the very least, if Bob wants to go ahead with the 23012, he should compare the curves for the 23012 and the AS5045 or AS5046 and see if there's anything to be gained by using the 23012 instead. Maybe he's already done that and has made his own judgement call. If so, great, go for it! Maybe I should just keep my mouth shut and answer his real question, which I did with the spar software that I posted. I reserve the right to say "I told you so" later on though... Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ------------------------------ Date: Sat, 20 Dec 2003 14:01:40 -0500 From: "Dana Overall" To: krnet@mylist.net Subject: Re: KR>airfoil design Message-ID: Content-Type: text/plain; format=flowed MIME-Version: 1.0 Precedence: list Message: 6 If I am not mistaken, this is the same or nearly the same airfoil on my Bonanza. While it is a great speed wing........trust me..........when it stalls, IT STALLS. If both wings are not absolutely identical you will see one wing drop dramatically sooner than the other. Great for a roller coaster ride but not a great wing for the KR. For what it matters, I was on the side of the runway at Covington and saw the wingtip up very, very, very close!! Dana Overall 1999 & 2000 National KR Gathering host Richmond, KY RV-7 slider, Imron black, "Black Magic" Finish kit Buying Instruments. Hangar flying my Dynon. http://rvflying.tripod.com do not archive _________________________________________________________________ Have fun customizing MSN Messenger — learn how here! http://www.msnmessenger-download.com/tracking/reach_customize ------------------------------ Date: Sat, 20 Dec 2003 10:50:01 -0900 From: Thomas Brock To: KRnet Subject: KR>I've learned a lot! Message-ID: <3FE4A7E3.31AF9149@arctic.net> Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854"; x-mac-creator="4D4F5353" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 7 Thanks to all of you veteran flyers and KR owners. I have a much better picture of what is needed for my location. Thanks to you, I was able to contact Bob Jennings in Anchorage, Alaska. Not only do I have his e-mail, but I spoke with him on the phone. I think he has agreed to "adopt" me as a future flyer. After speaking with Bob, I've learned that there are other KR planes in Alaska. I will see if I can locate these owners. Bob is amazing! He has quite a history as a pilot. In addition, his family has spent many years in the region where I live. He is very familiar with the weather, airports, and conditions in this part of the state. I keep you posted on my progress. Anyway, here's what I think is needed for me: 1. A tricycle gear 2. Largest engine I can find 2100 D, Corvair, or similar 3. Dual control, with throttle location in the middle of dash 4. A KR that is widened 5. A KR that will actually carry a flight instructor and a student pilot 6. A KR that has lights for night time VFR flying Bob also told me that Alaska recommends survival gear be carried. If I remember what he said correctly, it was that the survival gear would probably use most of the baggage area. Given the above requirements, do any of you know if such a KR aircraft exists? If not, could one be built that would meet these requirements? Am I still in the ball park as far as being able to realistically buy a KR? Again, I do not want a utility aircraft, but a fast flyer to use for cross country trips to improved airports. On, I forgot to mention in all of my previous posts, that our little town is basically built around our airport. We are a "hub" village and so feed other airstrips. As such, we have a new 5000 foot runway with just about all the bells and whistles: lights, nav aids, IFR capability, etc. We land cargo jets and Hercules aircraft here. It has been paved for about 2 years now. Let me know what you think. I am answering all individual replies as fast as I can. Thanks for slowing down and dampening my wide eyed blindness to the realities of these aircraft. Merry Christmas, Thomas ------------------------------ Date: Sat, 20 Dec 2003 10:57:42 -0900 From: Thomas Brock To: KRnet Subject: KR>Why trailer a KR? Message-ID: <3FE4A9B0.B573BC2F@arctic.net> Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854"; x-mac-creator="4D4F5353" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 8 I hope this is not too naive a question, but here goes: In my research, it seems that some very experienced pilots have bought their FLYING KR airplanes and trailered them to their home locations. Why would anyone want to disassemble the wings, buy a trailer, and drive the airplane back home? Am I missing something here? I can see if someone is buying an incomplete project plane, but a perfectly flying and operating KR? What gives here? In addition, you probably already know that there are some "silent" folks who are newbies that are learning lots from your explanations. I did not know this until people started contacting me and sharing their delight in my questions. So, please know that you are helping other people as well, whom you might not hear from. I will express their thanks also. Thomas ------------------------------ Date: Sat, 20 Dec 2003 11:44:20 -0800 From: larry severson To: tbsr@arctic.net, KRnet Subject: Re: KR>Why trailer a KR? Message-ID: <5.2.1.1.0.20031220114101.024c3d10@pop-server.socal.rr.com> In-Reply-To: <3FE4A9B0.B573BC2F@arctic.net> Content-Type: text/plain; charset="us-ascii"; format=flowed MIME-Version: 1.0 Precedence: list Message: 9 >Reasons to trailer the new aircraft, in increasing importance: 1. get your car home. 2. get to the area where you will have support as you start flying the plane. 3. get to where you can make repairs at your leisure if you ding it on the first flight. Larry Severson Fountain Valley, CA 92708 (714) 968-9852 larry2@socal.rr.com ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 255, Issue 2 *************************************