From: To: Subject: krnet Digest 9 Mar 2001 15:17:53 -0000 Issue 187 Date: Friday, March 09, 2001 7:18 AM krnet Digest 9 Mar 2001 15:17:53 -0000 Issue 187 Topics (messages 4475 through 4502): Re: KRNet contributions from Canada 4475 by: Rick Hubka Re: more tail stuff 4476 by: jshays 4477 by: KR2616TJ.aol.com Unsubcribe 4478 by: KR2616TJ.aol.com are we having fun yet? 4479 by: Steven Eberhart 4481 by: flykr2s.execpc.com 4482 by: jshays 4499 by: Jim V. Wickert Longitudinal static stability or CONTROL EFFECTIVENESS? 4480 by: R.H.Mole.open.ac.uk Three Years Ago Today!!! 4483 by: flykr2s.execpc.com NO NEED TO BE NASTY 4484 by: Bill Gaudlip Bullets and flames 4485 by: Edwin Blocher Stability - ugh! - again - the last time - that's a promise! 4486 by: R.H.Mole.open.ac.uk Landing gear question ... 4487 by: Albert Pecoraro 4490 by: Edwin Blocher 4491 by: Troy Johnson 4493 by: Albert Pecoraro 4494 by: Donald Reid 4495 by: Tracy & Carol O'Brien 4500 by: Albert Pecoraro Flames !! 4488 by: Cleo Greenhaw 4497 by: Livingstone, Danny (DJ) 4501 by: Bruce S. Campbell Wing-attach drill fixture ... 4489 by: Albert Pecoraro Missed? 4492 by: Frank Ross Wheel pants 4496 by: Dean Selby Mom here 4498 by: BSHADR.aol.com tail stuff yet agan 4502 by: Manager Bill Administrivia: To subscribe to the digest, e-mail: To unsubscribe from the digest, e-mail: To post to the list, e-mail: ---------------------------------------------------------------------- Date: Thu, 8 Mar 2001 09:17:04 -0700 To: From: "Rick Hubka" Subject: Re: KR> KRNet contributions from Canada Message-ID: <001b01c0a7eb$562e4540$d15dfea9@cg.shawcable.net> Hi People Just a reminder and note... from Marks message a few weeks ago. The PayPal option of paying on this site will not accept a Canadian address for Credit Card use so be sure to send your contribution for our mail list by mail only if you're from the far north :) to: Firehouse Network Consulting Post Office Box 1896 Cary, NC 27502 Me... I mailed em $5 bucks. Happy Building.. Rick Hubka rick@hubka.com ----- Original Message ----- From: "Mark Langford" To: Sent: Friday, February 23, 2001 12:23 PM Subject: KR> KRNet contributions > KRNetHeads, > > People are always asking me what they can do to support the KRNet list, and > this is it. Last year at about this time KRNet got really flaky and > eventually crapped out entirely. I signed us up for this particular > mailinglists.org service because I knew it was fast and reliable from > previous experience. It has definitely proven itself so far. Initially > the fee was $110 ($10 to get started, and $100 for the first year) and Dr. > Dean agreed that it would be a fitting contribution for Trailing Edge > Technologies to pay that bill, so it wasn't a sacrifice on my part. I think > we've definitely gotten our money's worth in the last year. The only > problems we've had are people accidently unsubscribing themselves by > clicking on the wrong address at the bottom, so be careful! > > Anyway, Alan Clegg, the guy that runs the service, has changed to a donation > system whereby regular users can donate a small sum to keep his service > afloat. The web site to make these donations is at > http://www.mailinglists.org/donations.html . You can use "PayPal" to make > the payment, or just send him a little check for maybe three or four dollars > to: > > Firehouse Network Consulting > Post Office Box 1896 > Cary, NC 27502 > > Note that this has nothing to do with Ross's "official KRNet" web site at > www.krnet.org , which requires some real money to support too. I'll leave > comments regarding that to him. We usually take up a collection at the > Gathering for that purpose but it was forgotten this year, and since it will > be hosted by a non-netter this year, will probably be forgotten again. > > Thanks a lot, > > Mark Langford, Huntsville, Alabama > see KR2S project N56ML at http://home.hiwaay.net/~langford > > > > --------------------------------------------------------------------- > To post to the list, email: krnet@mailinglists.org > > > To UNsubscribe, e-mail: krnet-unsubscribe@mailinglists.org > For additional commands, e-mail: krnet-help@mailinglists.org > > ------------------------------ Date: Thu, 8 Mar 01 10:23:53 -0600 To: Krnet From: jshays Subject: RE: KR> more tail stuff Ouch!!! You guys are getting mean in this discussion. How about the technical discussion less the nasty remarks? Thanks. So far here's some of my thoughts: 1 - Most of the really hardcore technical changes I hear being made are to - Planes not yet flying ... 2 - The reasoning behind the changes in #1 are mostly reasonable when described. 3 - Lack of smoking holes in the ground will validate the above two. 4 - It isn't unreasonable for somebody to point out any of the above. Okay based on that - you guys can technically debate things, BUT talk is cheap. When some of these planes have been flying for a while, then I think it is reasonable that the designer/modifier/builder/pilots can reasonably walk into a room and say - "this is the way it is, I know because I did it". Okay, that's my two cents. Regards, Jeff Hays. ------------------------------ Date: Thu, 8 Mar 2001 11:54:15 EST To: krnet@mailinglists.org From: KR2616TJ@aol.com Subject: Re: KR> more tail stuff Message-ID: --part1_f4.7dc9140.27d91337_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 3/8/01 11:29:07 AM Eastern Standard Time, jshays@interaccess.com writes: > BUT > Agree totally, Troy and Dean are both now flying with a new airfoil and modified horizontal stab. With that said, It has been mostly a wonderful experience being subscribed to the KRNet from it time on AOL to it's present state. Much work has been done in an attempt to make a great little airplane even better. The data is out there for all to see and critique. For those of you who don't know him, Richard Mole is considered the Tony Bingelis of Europe. Welcome Richard. I have never said a derogatory word about the KR and never would. I will continue to defend the quality research done to this little airplane. I am a firm believer that without this KRNet, RR would be worse off today than it already is. Has anyone noticed Jeff Scott, Mark Langford, Mike Mims, etc. are not responding to anything? Happy flying, The unsubscribed, Dana Overall 1999 & 2000 KR Gathering host Richmond, KY mailto:kr2616tj@aol.com http://www.geocities.com/CapeCanaveral/hangar/7085/ --part1_f4.7dc9140.27d91337_boundary-- ------------------------------ Date: Thu, 8 Mar 2001 12:47:20 EST To: kids2fly@nm.net, krnet@mailinglists.org From: KR2616TJ@aol.com Subject: Unsubcribe Message-ID: --part1_dd.11305e7b.27d91fa8_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Manager Bill, I appreciate the work you did on lifting bodies and your turbo Navion along with the children's flight simulator. I would recommend you contact Richard Mole and analysis the data he has. I believe you will find all of the comments I have made are supported by well documented research. I didn't want to unsubscribe without clarifying that. Dana Overall 1999 & 2000 KR Gathering host Richmond, KY mailto:kr2616tj@aol.com http://www.geocities.com/CapeCanaveral/hangar/7085/ --part1_dd.11305e7b.27d91fa8_boundary-- ------------------------------ Date: Thu, 8 Mar 2001 13:11:25 -0600 (CST) To: From: Steven Eberhart Subject: are we having fun yet? Message-ID: I belong to EAA Chapter 21 which is made up of a very dedicated bunch of people. I really look forward to the monthly meetings and the between meeting visits to builders local airplane factories. Having said that the most fulfilling couple of years I have spent were the ones where KRNet pulled together and accomplished something almost unheard of. We developed a new family of airfoils. It was not only working with the KRNet members that supported the project but working with the University of Illinois, Dr. Michael Selig, Dr. Ashok Gopalarathnam and engineers around the world that contributed to the projects success. THis project was followed by many people that you may have heard of. This project followed sound scientific principles and the results were published, again following sound scientific principles, for peer review. We have yet to receive anything but praise from peers that have reviewed the published data or the documented flight characteristics of the first two aircraft to fly with the new airfoils. THis is my last post defending all of the work that was done. Anyone that disagrees with anything that has been published should, again following sound scientific principles, publish their rebuttal of the design process and/or test data. Everyone that was associated with the project would eagerly review any rebuttals to the process that was followed, CFD analysis, wind tunnel test data or the flight test data from the two aircraft that are currently flying with the new airfoils. I don't know what more could have been done. Designed, tested and flown with results meeting or exceeding the original design goals. The stability project is following the same procedures and process that was used for the airfoil project. The first proof of principle aircraft is constructed but hasn't flown yet, however, all of the detailed analysis and design work has been done. I don't know what more can be said so I will now be quiet. RIP KRNet Steve Eberhart mailto:newtech@newtech.com ONE TEST IS WORTH A THOUSAND EXPERT OPINIONS BUT A THOUSAND OPINIONS ARE EASIER TO GET. --plagiarized from an unknown author (DAMN, HE WAS ONE SMART DUDE) ------------------------------ Date: Thu, 8 Mar 2001 13:30:38 -0600 (CST) To: Steven Eberhart From: flykr2s@execpc.com Cc: krnet@mailinglists.org Subject: Re: KR> are we having fun yet? Message-Id: <200103081930.NAA70565@nm0.nwbl.wi.voyager.net> Well, lets see....a lot of people who are the top guns of the KR Family are divorcing the KR Net. We lost Dana Overall today and sounds as if Steve Eberhart is pulling out. Who is next? What do we have to do to drive them off? It is really ashame this is happening and is a great loss of expertise and the wealth of knowledge they bring to the table. So what we should be doing is complimenting the efforts of these individuals and begging them to stay on the net. I for one am very sorry to lose these Top Guns and am sure this will hit home for most of us. Mark Jones mailto:flykr2s@execpc.com http://sites.netscape.net/n886mj/homepage > RIP KRNet > > Steve Eberhart > mailto:newtech@newtech.com > > ONE TEST IS WORTH A THOUSAND EXPERT OPINIONS BUT A THOUSAND OPINIONS ARE > EASIER TO GET. --plagiarized from an unknown author (DAMN, HE WAS ONE > SMART DUDE) > > > --------------------------------------------------------------------- > To post to the list, email: krnet@mailinglists.org > > > To UNsubscribe, e-mail: krnet-unsubscribe@mailinglists.org > For additional commands, e-mail: krnet-help@mailinglists.org > ------------------------------ Date: Thu, 8 Mar 01 13:47:46 -0600 To: , Steven Eberhart From: jshays Subject: RE: KR> are we having fun yet? Hey you guys, all of you. Quit being idiots and getting pissed off for nothing. Go out, eat lunch, turn off email and come back tommorrow. This is just an email list, BIG DEAL!!! I like reading all the new wave KR stuff, and I think the factory supporters have some good points as well. Quitting the list... That's a little carried away don't you think? Hey you want an argument, my Kitfox will kick the crap out of all of your KR's in a short grass field contest, and seriously so! Not too mention it's IFR. So there. Oh yeah, I do have a set of KR-2S plans as well... -Jeff. >===== Original Message From Steven Eberhart ===== >I belong to EAA Chapter 21 which is made up of a very dedicated bunch of >people. I really look forward to the monthly meetings and the between >meeting visits to builders local airplane factories. Having said that the >most fulfilling couple of years I have spent were the ones where KRNet >pulled together and accomplished something almost unheard of. We >developed a new family of airfoils. It was not only working with the >KRNet members that supported the project but working with the University >of Illinois, Dr. Michael Selig, Dr. Ashok Gopalarathnam and engineers >around the world that contributed to the projects success. THis project >was followed by many people that you may have heard of. This project >followed sound scientific principles and the results were published, again >following sound scientific principles, for peer review. We have yet to >receive anything but praise from peers that have reviewed the published >data or the documented flight characteristics of the first two aircraft to >fly with the new airfoils. > >THis is my last post defending all of the work that was done. Anyone that >disagrees with anything that has been published should, again following >sound scientific principles, publish their rebuttal of the design process >and/or test data. Everyone that was associated with the project would >eagerly review any rebuttals to the process that was followed, CFD >analysis, wind tunnel test data or the flight test data from the two >aircraft that are currently flying with the new airfoils. > >I don't know what more could have been done. Designed, tested and flown >with results meeting or exceeding the original design goals. The >stability project is following the same procedures and process that was >used for the airfoil project. The first proof of principle aircraft is >constructed but hasn't flown yet, however, all of the detailed analysis >and design work has been done. I don't know what more can be said so I >will now be quiet. > > > >RIP KRNet > >Steve Eberhart >mailto:newtech@newtech.com > >ONE TEST IS WORTH A THOUSAND EXPERT OPINIONS BUT A THOUSAND OPINIONS ARE >EASIER TO GET. --plagiarized from an unknown author (DAMN, HE WAS ONE >SMART DUDE) > > >--------------------------------------------------------------------- >To post to the list, email: krnet@mailinglists.org > > >To UNsubscribe, e-mail: krnet-unsubscribe@mailinglists.org >For additional commands, e-mail: krnet-help@mailinglists.org > >. ------------------------------ Date: Fri, 9 Mar 2001 04:24:12 -0500 To: "INTERNET:flykr2s@execpc.com" From: "Jim V. Wickert" Cc: Steven Eberhart , krnet@mailinglists.org Subject: Re: KR> are we having fun yet? Message-ID: <200103090424_MC2-C833-DE9E@compuserve.com> Mark, = I agree with you, what is the KRnet going to do with out this eliet group= of builders that support the questions and the development???? If every time some one has an idea and or some concept for development and we Kill= them at the stake where would the KR be???? Ken and RR is no more yes the= y have a PO Box but.... Without a builders support network and without th= e people on the net that report the findings or success, where would the people who have developed the next generation KR concepts and benefits be= and where would the interest and success and progress BE???? I think everyone should take a few steps back and realize how valuable th= is network is. I am a grad doc in engineering and I must say I have not see= n, read or heard anything new or newfound on this net the would change the concept or design of the KR without a lot of people working together to prove the concept. No one in my mind is the total souce. Please give th= e people room and when they have done it let's liesten? Because there is a= world of developers that will help us When someone brings a point out let's be constructive not destroy. Just = to make a point of reality, everyone that has talked about the extension of the tail and the HS we must understand, has some one thought about what effect this has on the torsional stress on the main fuse. We can talk al= l day about what we think we know but did you design the plane??? Ken did a= nd there are a lot of the KR's flying??? There are also some very impressiv= e groups that have taken personal position of the development of the KR tod= ay and this has made a very much improved plane. Respect Respect? Jim W ------------------------------ Date: Thu, 8 Mar 2001 19:22:13 -0000 To: krnet@mailinglists.org From: R.H.Mole@open.ac.uk Subject: Longitudinal static stability or CONTROL EFFECTIVENESS? Message-ID: Bill, The issue of a forward cg and whether the elevator can supply sufficient pitch up control effectiveness in the landing configuration and in ground effect (not an academic point either - its a low wing remember?) is an issue of CONTROL not an issue related to STABILITY, as I am sure that you will agree - now that its been pointed out. Perkins and Hage titled their book 'Performance, Stability and Control' because these are related, but different concepts. The issue, with respect, is not whether there is adequate elevator effectiveness with fwd cg - No, netters, I haven't checked this analytically, because there had been no serious prior indication that this was ever a problem. If I'm wrong here then please be tolerant. I agree that it could become a limiting factor if the elevator is reduced in area. Whether there is adequate static margin stick free at the aft cg (and whether the stick force per g is acceptable) is primarily a STABILITY issue. If you haven't made a stability analysis, after all, then thats quite OK until you start to fire blanks at other people who have done so - then the hired gun starts to look rather like a would-be Emperor without any clothes? Richard ------------------------------ Date: Thu, 8 Mar 2001 14:31:47 -0600 (CST) To: krnet@mailinglists.org From: flykr2s@execpc.com Cc: Subject: Three Years Ago Today!!! Message-Id: <200103082031.OAA54527@nm2.nwbl.wi.voyager.net> Three years ago today I became a builder of a KR-2S as this was the day my spruce and plywood arrived from Wicks. Wow what a feeling to start building a airplane!!! Everyone in my family thought I was nuts and now they are all asking when will it be finished so they can ride in it. For those of you who are wondering what the cost of building is, I have invested a total of $6,047.31 as of today. This includes all major dollar components to finish my plane. I must admit I did get some real bargins on some parts. Also, it includes a Corvair engine which is very close to being finished. I have thoroughly enjoyed the building of my KR-2S and am sure the flying will even be better. I have also been a member of this list for three years and learned more here than anywhere else. I Thank all of you who have helped me with my plane. If any of you would like to see what stage my project is at today, visit my site at: http://sites.netscape.net/n886mj/homepage Mark Jones ------------------------------ Date: Thu, 8 Mar 2001 15:37:07 -0500 To: "KRNET" From: "Bill Gaudlip" Subject: NO NEED TO BE NASTY Message-ID: <004001c0a80f$8bb45140$d4131204@BillGaudlip> ------=_NextPart_000_003D_01C0A7E5.A1FAEE20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hey Fellow Netters, I have only been on the KR Net for = about a month but I've hooked up with a lot of super people!! My KR2 is finished and flying after eight and a half years and yes its = squirrelly and touchy and all that stuff but I sort of knew it was going = to be that way when I started building in ' 91.If I wanted to fly a = truck I'd have bought a Cessna or Cherokee or something. I know there is = certainly room for improvement but pissing people off isn't the way to = do it. I hope everyone can cool down and get back to business. By the way I'll be at Sun-N-fun and I'll look up the KR = booth and talk with as many as I can. I already contacted Frank Ross and = several others. See ya there!! No, I won't be flying in, I only have = 17.5 total hrs on the plane. Maybe next year. Bill Gaudlip Hooversville PA ------=_NextPart_000_003D_01C0A7E5.A1FAEE20-- ------------------------------ Date: Thu, 8 Mar 2001 15:54:32 -0600 To: "KRNet" From: "Edwin Blocher" Subject: Bullets and flames Message-ID: <000e01c0a81a$5d4b35c0$cfe879a5@computer> ------=_NextPart_000_000B_01C0A7E8.1137E160 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable If you want to shoot somebody down or flame them, do it off net. I = respect a lot of builders facts and ideas. If I don't I have learned how = to delete them. As for the tail end of the plane I'll go with Dana. = Now that said I'll report that I visited with Bill Kirkland = yesterday on the Emerald Coast of Florida. Looked at the pictures of his = KR and had a nice visit. What he hadn't told us (or I missed it) is that = he had a heart attack just before Christmas. He seems to be doing well = but has lost his medical for 6 months. = We are going to start building a new home for my KR = next month in Florida so my progress has slowed down for a few months. = Mark L., Bill is going to try to get in touch with you on his = way back to Ontario around the end of the month. Ed Ed Blocher Moody, Alabama kr-n899eb@mindspring.com ------=_NextPart_000_000B_01C0A7E8.1137E160-- ------------------------------ Date: Thu, 8 Mar 2001 22:28:02 -0000 To: krnet@mailinglists.org From: R.H.Mole@open.ac.uk Subject: Stability - ugh! - again - the last time - that's a promise! Message-ID: I felt that this post was required to try and clear the air. If you not a 'techie' its probably best to skip it completely. All the information in this posting is supplied without warranty of any sort implied or explicit. Aft cg limits shown here are calculated in good faith - but they have NOT been independently checked. They are not authoritative. They are one man's best shot. Results of own analysis; neutral points stick fixed and stick free. Datum: all aft of LE of stub wing kr2 Kr2S Stick fixed np 12.75" 13.5" Stick free np 11.8" 1.3 lbs/g at this limit 12.2" 1.3 lbs/g at this limit So there is very little difference, just 0.4", between the calculated aft cg for the kr2 and the kr2S. All numbers are power-off and the de-stabilising effects of power will bring them forward. Note that at least two Airworthiness authorities restrict the aft cg position: Australia aft cg limit is 12" aft of LE on stub wing (info posted by Malcom Bennet, krnet 23.12.98) South Africa aft cg limit is 13.44" aft of LE on stub wing (info posted by Kobus De Wet, 27.12.98) The stick fixed np is included in the table for interest only because the stick free case is always more stringent. It is possible to fly with the cg aft of the stick-free np but it is VERY dangerous and foolish to try this. The stick free manoeuvre margin is what makes it possible and this depends upon air density, so the margin reduces with density altitude. Bigger tails and moment arms both increase the tail volume and move the stick fixed np further aft. But this may be an illusory gain. What is really required is a rearward shift in the stick free n.p. The kr elevator floats with the relative wind because it has no aerodynamic balance. This floating tendency will always ensure that the stick free np is well forward of the stick fixed np whatever the tail volume may be. Aerodynamic balance is one (but only one) approach to improving the situation. Hence Dana's elevator horns. These horns add area and so they do improve the stick fixed np. More crucially, they reduce the tendency of the elevator to float with the relative wind. The stick free np is then much closer to the stick fixed np. It is hard to judge the correct horn geometry. Dana's horns are 'unshielded horns'. It is imperative to use the best data sheets available (ant to correct for the effects of the elevator cut-out). Do not try to eye-ball this for yourself as over-balancing is more dangerous than no balance. To do a longitudinal stability analysis requires a lot of work. These are some of the data that are required to be estimated to a high degree of accuracy. My full analysis covers 7 sides of single spaced paper. Estimates are required for: Wing lift slope a1 per rad (from Reynolds number, included angle at TE, transition point, Aspect ratio etc) Wing mean aerodynamic chord mac Tail lift slope a1t per rad (as for wing plus account of elevator cut out) Tail volume (from wing and tail areas, mac and tail arm) Rate of change of downwash with wing alpha Elevator lift slope a2 per rad Hinge moment rate due incidence b1 Hinge moment rate due elevator deflection b2 Stick free factor = 1- a2/a1t*b1/b2 Elevator gearing Longitudinal a/c relative density So it's a long haul and fraught with opportunity for unintended error and plain mistakes. The table at the start of this post is my best shot. It is offered in good faith. Richard ------------------------------ Date: Thu, 8 Mar 2001 18:20:41 -0500 To: "kr2s group" From: "Albert Pecoraro" Subject: Landing gear question ... Message-ID: <004701c0a826$6737aee0$f2d4b23f@steelcase.com> ------=_NextPart_000_003D_01C0A7FC.7BB301A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Netters, For taildraggers, does anyone know the general rule regarding the angle = of forward sweep of the axle centers with respect to the empty CG of the = plane? Is it somewhere between 15 and 20 degrees?=20 For example, let's say I were to look at a side-view drawing of my KR-2S = and calculate/estimate the center of gravity of the airplane (empty) as = being a point 4" above the forward center spar (and perpendicular with = the centerline). Let's call the position of the center of the main gear axle point A, the = CG point B, and a point C below point B such that the angle at C is 90 = degrees. Should angle B fall somewhere between 15 and 20 degrees? If this is so, = then my axles need to move another 4" forward - currently, they rest 4" = in front of the front of the main spar. I hope I haven't confused anyone. Thanks in advance. Albert ------=_NextPart_000_003D_01C0A7FC.7BB301A0-- ------------------------------ Date: Thu, 8 Mar 2001 17:27:08 -0600 To: "Albert Pecoraro" , "kr2s group" From: "Edwin Blocher" Subject: Re: KR> Landing gear question ... Message-ID: <003c01c0a827$4ca8dda0$cfe879a5@computer> Albert, It depends on your tail :). I couldn't resist that. Seriously that is a good question and one that I am looking at now. If I mount my spring gear on the front of the front spar I will have about 4 1/2". But then again it depends on the tail. Hope we can get some informative answers. Ed Blocher Moody, Alabama kr-n899eb@mindspring.com ----- Original Message ----- From: Albert Pecoraro To: kr2s group Sent: Thursday, March 08, 2001 5:20 PM Subject: KR> Landing gear question ... Netters, For taildraggers, does anyone know the general rule regarding the angle of forward sweep of the axle centers with respect to the empty CG of the plane? Is it somewhere between 15 and 20 degrees? For example, let's say I were to look at a side-view drawing of my KR-2S and calculate/estimate the center of gravity of the airplane (empty) as being a point 4" above the forward center spar (and perpendicular with the centerline). Let's call the position of the center of the main gear axle point A, the CG point B, and a point C below point B such that the angle at C is 90 degrees. Should angle B fall somewhere between 15 and 20 degrees? If this is so, then my axles need to move another 4" forward - currently, they rest 4" in front of the front of the main spar. I hope I haven't confused anyone. Thanks in advance. Albert ------------------------------ Date: Thu, 8 Mar 2001 16:48:18 -0700 To: "Albert Pecoraro" , "kr2s group" From: "Troy Johnson" Subject: RE: KR> Landing gear question ... Message-ID: <000401c0a82a$4040b850$0300a8c0@TROYS> ALbert, A while back I picked up Pazmany's book on landing gear design as I will have to construct a different landing gear for my "KR?"...It is quite technical in nature but the bottom line is yes 15 to 20 degrees ahead of the CG is a good guideline. Troy Johnson > -----Original Message----- > From: Albert Pecoraro [mailto:gryphonflier@earthlink.net] > Sent: Thursday, March 08, 2001 4:21 PM > To: kr2s group > Subject: KR> Landing gear question ... > > > Netters, > > For taildraggers, does anyone know the general rule regarding the > angle of forward sweep of the axle centers with respect to the > empty CG of the plane? Is it somewhere between 15 and 20 degrees? > > For example, let's say I were to look at a side-view drawing of > my KR-2S and calculate/estimate the center of gravity of the > airplane (empty) as being a point 4" above the forward center > spar (and perpendicular with the centerline). > > Let's call the position of the center of the main gear axle point > A, the CG point B, and a point C below point B such that the > angle at C is 90 degrees. > > Should angle B fall somewhere between 15 and 20 degrees? If this > is so, then my axles need to move another 4" forward - currently, > they rest 4" in front of the front of the main spar. > > I hope I haven't confused anyone. > > Thanks in advance. > > Albert > ------------------------------ Date: Thu, 8 Mar 2001 19:14:57 -0500 To: "kr2s group" From: "Albert Pecoraro" Subject: Re: KR> Landing gear question ... Message-ID: <007b01c0a82d$fbf05440$f2d4b23f@steelcase.com> > A while back I picked up Pazmany's book on landing gear design as I will > have to construct a different landing gear for my "KR?"...It is quite > technical in nature but the bottom line is yes 15 to 20 degrees ahead of > the CG is a good guideline. > > Troy Johnson Troy, Thanks for the feedback. Another question, if you don't mind: I know how to determine the CG along the longitudinal axis, but how do I determine it along the "yaw" axis? How far above/below the top of the spar is the CG? Wouldn't this be the point from which I would want to calculate my measurements? Thanks. Albert ------------------------------ Date: Thu, 08 Mar 2001 20:23:50 -0500 To: From: Donald Reid Subject: Re: KR> Landing gear question ... Message-Id: <5.0.2.1.0.20010308201534.009f5b20@pop.erols.com> --=====================_1932143==_.ALT Content-Type: text/plain; charset="us-ascii"; format=flowed >Thanks for the feedback. Another question, if you don't mind: > >I know how to determine the CG along the longitudinal axis, but how do I >determine it along the "yaw" axis? How far above/below the top of the spar >is the CG? Wouldn't this be the point from which I would want to calculate >my measurements? > >Thanks. In order to do this, you need to perform at least two different cg measurements. One with the fuselage level (just like normal), and at least one other with the tail displaced as far up or down as possible in a stable configuration. With a tail wheel aircraft, this means doing another w and b with the tail down. This process is not extremely accurate with the type of measuring equipment that you can find in the average home shop. The cg position that you calculate in each case are identical, but they "look" very different when you examine the raw numbers. Either mathematically or graphically, you find out where they intersect inside the fuselage. In practical terms in a KR, this point will be on the order of 6 inches above the wing. Don Reid mailto:donreid@erols.com Bumpass, Va Visit my web sites at: KR2XL construction: http://users.erols.com/donreid/kr_page.htm Aviation Surplus: http://users.erols.com/donreid/Airparts.htm EAA Chapter 231: http://eaa231.org Ultralights: http://usua250.org --=====================_1932143==_.ALT-- ------------------------------ Date: Thu, 08 Mar 2001 18:20:55 -0800 To: "Albert Pecoraro" , "kr2s group" From: Tracy & Carol O'Brien Subject: Re: KR> Landing gear question ... Message-Id: <3.0.3.32.20010308182055.00cbbd00@localaccess.com> Albert, et al, Pazmany's "Landing Gear Design for Light Aircraft, Volume 1" page 7 shows a profile view of a taildragger with the optimal angular relationship of 15 to 25 degrees shown: The airplane is in level flight position and the angle relationship is between the ground contact point of the tires and the aircraft CG. (The actual vertical location of the CG will affect the angular relationship. Paz's illustration looks like his PL4A and he shows the vertical CG about 4-5" below the top longeron for this design.) Regards, Tracy O'Brien >For taildraggers, does anyone know the general rule regarding the angle of forward sweep of the axle centers with respect to the empty CG of the plane? Is it somewhere between 15 and 20 degrees? > >For example, let's say I were to look at a side-view drawing of my KR-2S and calculate/estimate the center of gravity of the airplane (empty) as being a point 4" above the forward center spar (and perpendicular with the centerline). > >Let's call the position of the center of the main gear axle point A, the CG point B, and a point C below point B such that the angle at C is 90 degrees. > >Should angle B fall somewhere between 15 and 20 degrees? If this is so, then my axles need to move another 4" forward - currently, they rest 4" in front of the front of the main spar. > >I hope I haven't confused anyone. > >Thanks in advance. > >Albert > ------------------------------ Date: Fri, 9 Mar 2001 07:49:51 -0500 To: From: "Albert Pecoraro" Subject: Re: KR> Landing gear question ... Message-ID: <001801c0a897$6fa6bbe0$13d4b23f@steelcase.com> > >I know how to determine the CG along the longitudinal axis, but how do I > >determine it along the "yaw" axis? How far above/below the top of the spar > >is the CG? Wouldn't this be the point from which I would want to calculate > >my measurements? > > > In order to do this, you need to perform at least two different cg > measurements. One with the fuselage level (just like normal), and at least > one other with the tail displaced as far up or down as possible in a stable > configuration. With a tail wheel aircraft, this means doing another w and > b with the tail down. > > This process is not extremely accurate with the type of measuring equipment > that you can find in the average home shop. > > The cg position that you calculate in each case are identical, but they > "look" very different when you examine the raw numbers. Either > mathematically or graphically, you find out where they intersect inside the > fuselage. In practical terms in a KR, this point will be on the order of 6 > inches above the wing. Don and everyone who responded to this question: Thanks for sharing your knowledge on this area. I learned yet another thing from KRNet. :-) Based on this new information I have to extend my gear legs forward another 4" or so. I'll have to go back to the drawing board and modify the gear leg so that it swings out a bit more. Currently, the enter of the gear axles are 4" away from front of the main spar. This would have been fine if I had made my gear legs the same dimensions as the Diehl gear. For those of you who are familiar with Dr. Dean's gear leg design, his gear places the centers of the axles 10" forward of the main spar, and they are a bit longer than mine. I think mine will be around 8". Take care and happy building and/or flying. Albert ------------------------------ Date: Thu, 8 Mar 2001 17:34:26 -0600 To: From: "Cleo Greenhaw" Subject: Flames !! Message-ID: <001a01c0a828$528ffc20$406a67ce@cleogree> ------=_NextPart_000_0017_01C0A7F6.057019C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Netters: There are only a few people who think they are qualified to = blast other members and/or builders. I hope that the "Moms" will take = a hand in this and issue a warning to make this a friendly net, and not = a net for trying to admonish other members who seek help, not to follow = those on an ego trip, with their beliefs which are for the most part = are bogus anyway. Cleo@fullnet.net=20 ------=_NextPart_000_0017_01C0A7F6.057019C0-- ------------------------------ Date: Fri, 9 Mar 2001 07:25:57 +0200 To: krnet@mailinglists.org From: "Livingstone, Danny (DJ)" Subject: RE: KR> Flames !! Message-ID: Hello guys As a South African and no KR agent in the country to speak of, I rely heavily on the KR-net for most of my assistance on problems or queries I may have. If we loose the guys with all the know-how from the net it will be a sad day not to mention dangerous in some cases. I think that any member flames, etc. any other member the Net "moms" should suspend that person immediately and without warning until that person has facts to prove what he has said. That said, we will disagree with each other now and then but that is what "reply" button is for. It allows for personal communication between two parties. They can discuss the differences between them and if necessary send a more detailed explanation or retract their statement as the case may be. I hereby give the Net "moms" my support on this matter, I will make the "flamer" think twice before he flames someone over the net. I would like to say to those of you who made the KR-net what it is today, thank you for your effort, It is definitely appreciated by people like me. Don't leave the net, your input is valuable to more than most of us. Never mind the negative few. Danny Livingstone South Africa > -----Original Message----- > From: Cleo Greenhaw [SMTP:cleo@fullnet.net] > Sent: Friday, March 09, 2001 1:34 AM > To: krnet@mailinglists.org > Subject: KR> Flames !! > > Netters: There are only a few people who think they are qualified to > blast other members and/or builders. I hope that the "Moms" will take a > hand in this and issue a warning to make this a friendly net, and not a > net for trying to admonish other members who seek help, not to follow > those on an ego trip, with their beliefs which are for the most part are > bogus anyway. Cleo@fullnet.net ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. All opinions expressed are the sender's own and not necessarily that of the employer. ********************************************************************** ------------------------------ Date: Fri, 09 Mar 2001 08:00:25 -0500 To: Cleo Greenhaw From: "Bruce S. Campbell" CC: krnet@mailinglists.org Subject: Re: KR> Flames !! Message-ID: <3AA8D3E9.D29E4D81@gte.net> Many of the Moms have already dropped off--that tell you something? Bruce S. Campbell Tampa Cleo Greenhaw wrote: > Netters: There are only a few people who think they are qualified to blast other members and/or builders. I hope that the "Moms" will take a hand in this and issue a warning to make this a friendly net, and not a net for trying to admonish other members who seek help, not to follow those on an ego trip, with their beliefs which are for the most part are bogus anyway. Cleo@fullnet.net ------------------------------ Date: Thu, 8 Mar 2001 18:29:55 -0500 To: "kr2s group" From: "Albert Pecoraro" Subject: Wing-attach drill fixture ... Message-ID: <004e01c0a827$b023c8e0$f2d4b23f@steelcase.com> ------=_NextPart_000_004B_01C0A7FD.C5DC7DA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Netters, I had a friend at a local machine shop fabricate a wing-attach drill = fixture out of steel. He also put in drill bushings so that the = drill-bit won't wobble. If you are at the point where you have to drill the holes for your = wing-attach fittings and would like to use this tool, let me know so I = can plan on how to get this to you in the quickest/cheapest manner.=20 BTW: I haven't picked it up yet, and I'm going to be out of town this = weekend, so this won't happen for at least a few weeks. Nonetheless, let = me know if you are interested. Reply direct please: gryphonflier@earthlink.net Thanks. Albert ------=_NextPart_000_004B_01C0A7FD.C5DC7DA0-- ------------------------------ Date: Thu, 8 Mar 2001 16:03:16 -0800 (PST) To: krnet@mailinglists.org From: Frank Ross Cc: KR2616TJ@aol.com, Steven Eberhart Subject: Missed? Message-ID: <20010309000316.13842.qmail@web4703.mail.yahoo.com> Did I miss something? Someone is blasting the new airfoil again? I have been through all the postings and have not found anyone criticizing it and yet folks are leaving the sandbox because, they say, someone criticized the new airfoil. Where is it? Who did it this time? Is there anyone who hasn't heard how much time, effort, brains, sweat, tears, saliva and key-board pounding has gone into defending it? Why? I'd be embarrassed if I had designed that thing and so many used it as an excuse to beat to death everyone who disagreed with them on every little thing. The KRnet isn't going to die because a few want to go off and pout. I hope when they're through pouting, they'll come back and play another day. I also hope they'll quit acting like every little disagreement is about the new airfoil, or a reason to shut down the KRnet, or, especially quit attacking people who don't agree with them. Frank Ross, San Antonio, TX --- KR2616TJ@aol.com wrote: > > Agree totally, Troy and Dean are both now flying > with a new airfoil and > modified horizontal stab. > > With that said, > > It has been mostly a wonderful experience being > subscribed to the KRNet from > it time on AOL to it's present state. Much work has > been done in an attempt > to make a great little airplane even better. The > data is out there for all > to see and critique. > I am a firm believer that > without this KRNet, RR would be worse off today than > it already is. > > Has anyone noticed Jeff Scott, Mark Langford, Mike > Mims, etc. are not > responding to anything? > > Happy flying, > > The unsubscribed, > > Dana Overall __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ ------------------------------ Date: Thu, 8 Mar 2001 20:42:31 -0600 To: "krnet" From: "Dean Selby" Subject: Wheel pants Message-ID: <000c01c0a842$9791da40$4d5818d0@deans> ------=_NextPart_000_0009_01C0A810.4BE33B20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Does anyone know, or is he on this list, the guy at last years gathering = that was making fiberglass parts. The one part I may just buy instead = of make- wheelpants. If you remember please e-mail me with his name and = number. As I begin to clean up the plane I hope to see some pretty good = performance. Thanks, Dean Selby deans@usit.net ------=_NextPart_000_0009_01C0A810.4BE33B20-- ------------------------------ Date: Fri, 9 Mar 2001 03:01:08 EST To: krnet@mailinglists.org From: BSHADR@aol.com Subject: Mom here Message-ID: <41.874aeaa.27d9e7c4@aol.com> --part1_41.874aeaa.27d9e7c4_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Folks: I'm not sure why I have to come into the sandbox over all of this silliness. As my Mom would say "Don't make me come out there or I'll be giving you something to cry about..." How much more do I have to say on the subject? Lest I have to start carding each of you at the door, I believe everyone who signed up on the list is an adult. Now I might add that adults have a higher level of social responsibility for proper social discourse, tikes in a sandbox get off the hook with lower standards. If you are trying to convince me that you guys should have the "tike standard," I'm calling the truant officer and getting your butts hauled back to grade school. Some of you may be leaning a tad over the line in the (dis)respect department. Ask yourself why? Did you get your feelings hurt? Did someone call your baby ugly? So be it. Part of life--happens all the time! Attack and counter attack serves no good cause. Look at all of the "tribal" behavior around the world every day. "My people are better than your people...my God is better than your God...groups mass killing other groups who they don't like, etc..." Groups who do not learn from history are doomed to repeat same. Don't let this list degenerate to the level of the RecAviation list. Those of you who are offended, try exercising your pinkie on the delete key. It is good therapy. Me thinks all of us individually using the delete key will help keep Mom from doing it with more certainty in the subscribers department. I've met and otherwise know many of you, and frankly, some of the postings don't square with the person I think I know. What is a Mother to think? Convince a man against his will, he's of the same opinion still. Randy "Distraught NetMom" Stein Soviet Monica, CA PS - For those of you who had the stomach to read this far, get in the habit of posting the facts, supporting the facts, and only the facts. Opinions and disparaging comments, like armpits, are plentiful and they all happen to stink when they are not your own... PS PS - Don't start writing a bunch of "me too'" posting on the list about what I just rambled about above. Try post something good instead. How about some airplane construction talk or congrats to birds that just started flying or give us some links to new and interesting websites...well (sigh), you get the picture. --part1_41.874aeaa.27d9e7c4_boundary-- ------------------------------ Date: Fri, 09 Mar 2001 08:23:50 -0700 To: Krnet From: Manager Bill Subject: tail stuff yet agan Message-ID: <3AA8F583.19EFFEC9@nm.net> Tail Stuff again Thursday First things first: I have been challenged to knock off the discussion and publish the results of my calculations for the KR-2 and KR-2S. I did these calculations six years ago at the request of Jeannette Rand in response to concerns by the Australian CAA. The stick fixed, power off neutral point of the KR-2 is 7.24 inches aft of the wing 25 percent mean aerodynamic chord, or 31.06 inches aft of the aft face of the firewall. This is 3 inches further aft than the aft limit shown in the KR-2 manual I have had since about 1988. The stick fixed, power off neutral point of the KR-2S is 7.12 inches aft of the wing 25 percent mean aerodynamic chord, or 33.18 inches aft of the aft face of the firewall. This is a bit more than 5 inches behind the aft limit in the Rand manual (I assume the c.g. limits for the -2 and -2S are the same). The difference between the two locations is almost entirely due to the 2.0 inch difference between the locations of the 25 percent mean aerodynamic chords of the two airplanes, and this difference is due to the increased wingspan and reduced tip chord of the KR-2S relative to the KR-2. Note that within the accuracy of calculation, the neutral points are exactly the same distance behind the 25 percent mean aerodynamic chords of the two airplanes.( Incidentally, don’t take the .01 inch accuracy of the numbers too seriously, they are probably no better than about .15 inches.) For those who want to check my neutral point calculations, here are the numbers. For the KR-2: wing area 74.22 square feet wing span 20.21 square feet mean aerodynamic chord 3.52 feet aspect ratio 5.50 lift curve slope 4.401 per radian location of 25 percent mean aerodynamic chord 24.06 inches aft of the firewall aft face fuselage length 174 inches fuselage width 38.12 inches horizontal tail area 10.94 square feet horizontal tail span 20.21 feet mean aerodynamic chord 3.52 feet aspect ratio 3.20 lift curve slope 3.482 per radian location of 25 percent mean aerodynamic chords 121.05 inches aft of the firewall aft face and 30 inches above the zero lift plane of the wing. downwash derivative at the horizontal tail 0.36 degrees per degree angle of attack For the KR-2S: wing area 81.15 square feet wing span 23.54 feet mean aerodynamic chord 3.28 feet aspect ratio 6.83 lift curve slope 4.707 per radian location of 25 percent mean aerodynamic chord 26.06 inches aft of the firewall aft face fuselage length 190 inches fuselage width 38.12 inches horizontal tail dimensions are the same as KR-2 except the location of the 25 percent mean aerodynamic chord, which is 137.05 inches aft of the firewall and 34 inches above the wing zero lift line. In response to another question, I have not and am not building a KR, and I have never flown one of any kind. My personal airplane is a large, comfortable, very stable, ponderous, slow, and inefficient 1947 Navion; I have owned it since 1977. I have no axe to grind one way or another. However, I do lean toward improvements to the airplane that can be made by builders who are already flying. This is the reason I have stated that , as Dana Overall stated: stability is determined by the location of the center of gravity in relation to the center of pressure (lift). That is a qualitative, but nevertheless true, statement. More precisely, I will quote from NACA Technical Report No. 971, Appreciation and Prediction of Flying Qualities, by William H. Phillips, published in 1948: An airplane that is stable with stick fixed requires a forward movement of the stick to increase speed (same thing as decreasing angle of attack or lift coefficient) and a rearward movement of the stick to decrease speed (same thing as increasing angle of attack or lift coefficient). As the center of gravity moves aft toward the point of neutral stability, it takes less and less stick motion to pitch the airplane through its full range of lift, until at the neutral point, no motion at all is required, and aft of the neutral point the motion is reversed. This is a definition that anyone who flies can understand. Next, Phillips defines the stick-free stability: An airplane that is stable in pitch with its stick free requires not only forward motion to increase speed, but also requires that the stick must need a push force to move it forward and must need a pull force to move it aft. Because the elevator generally tends to float with the relative wind, the effective stabilizing area of a tail with the elevator free to move is less than with the stick fixed, and the aft limit of the center of gravity with stick free is more forward than the aft limit with stick fixed. This can result in a condition that appeals to the aerobatically inclined: there is a center of gravity that is slightly stable with stick held fixed, but that lets you move it back and forth with no resistance. This can be fun for awhile, but it gets tiresome if you are trying to fly straight and level on a cross country. Incidentally, stick free stability is what the FAA requires; in fact, it requires that the stability margin be high enough and control system slop and friction be low enough that with the airplane trimmed to zero stick force at any speed, it will return to within 10 percent of that speed if the stick is pushed or pulled for a moment and then released. Nothing here says that the only way to get more distance between the center of gravity and the stick-fixed or stick-free neutral points is by moving the neutral points to the rear. The same effect can be gotten by balancing the airplane so its center of gravity is more forward. Now, just how far forward can the center of gravity be? First, for a taildragger especially, it can’t be so nose heavy that it falls over when brakes are applied. Second, it can’t be so nose heavy that the tail can’t balance it throughout its speed range. The landing gear problem can be solved by tilting the gear legs forward, so let’s look at the tail effectiveness, starting with the condition for maximum lift. S.F. Hoerner in his book, Fluid Dynamic Lift, lists the max lift coefficient of the RAF 48 as 1.45. For the KR-2S wing, the angle of attack for this coefficient is 1.45/4.71 = .308 radians or 17.6 degrees. Including 3.5 degrees incidence, the zero lift line of the wing is approximately 3 degrees nose down, so the airplane angle of attack at maximum lift is 14.6 degrees. This should be the angle of attack of the horizontal tail, but that neglects the downwash behind the wing. The stability calculations gave the downwash as 36 percent, so the true angle of attack of the tail is 14.6 degrees minus 0.36 times 17.6 degrees, which equals 8.3 degrees. The max elevator deflection is 30 degrees up, and the elevator effectiveness, assuming 50 percent chord ratio, is about 65 percent. This means that 30 degrees elevator deflection is equivalent to 20 degrees angle of attack. Subtract 8.3 degrees from that, and the down tail load is what can be produced by 11.7 degrees angle of attack. The tail lift curve slope is 3.482, so the tail lift coefficient is -0.711. The area of the KR-2S tail is 10.94 square feet, and the dynamic pressure at max lift (1050 lb weight) is 8.94 pounds per square foot. Then the maximum tail down load with 30 degrees up elevator at maximum lift is 69.5 pounds. The 25 percent mean aerodynamic chord of the tail is 8.08 feet aft of the wing 25 percent mean aerodynamic chord, so the nose up moment at the 25 percent wing chord is 562 foot pounds. The airplane weighs 1050 pounds (in this example), but you can’t get a full forward center of gravity with two persons, so we should subtract 170 pounds. This reduces the dynamic pressure at stall to 7.49 pounds per square foot, so the maximum down load at the tail can only be 58.2 pounds and the nose up moment can only be 471 pounds. Then the furthest forward the center of gravity can be is 562/1050 = 0.535 feet, or 6.42 inches forward of the 25 percent wing mean aerodynamic chord. This is 17.6 inches aft of the aft face of the firewall. My KR-2 construction manual (NOTE: KR-2, not KR-2S) gives the forward limit as 8 inches aft of the wing leading edge, or only 4.0 inches forward of the 25 percent mean aerodynamic chord. So these calculations let you have 2.4 inches more forward center of gravity than specified in the plans. However, be aware that I have neglected the tail down load required to counter the nose-down moment of the wing-fuselage combination that is due to camber; I have neglected any power effects, and I have used an elevator effectiveness curve that ignores the gap between the elevator and the stabilizer. I have included all the details of this calculation to give you all an idea of what is involved in analyzing an airplane design. Note that I have not done the calculation of the tail angle of attack, elevator deflection, and down load required for the high speed dive condition, because I don’t have the zero lift pitching moment coefficient for the RAF 48. However, all this is mere discussion. The proof of the pudding is that dozens of KR-1’s and KR-2’s, and not a few KR-2S’s, have been built and flown for hundreds of hours. This does not mean it can’t be improved. The early Bonanza revolutionized the post WWII aviation market, but compared to the Bonanza that has evolved since 1946 it is completely outclassed. Let’s do the same for the KR. Well, I’ve gotten carried away by enthusiasm again. I had some other stuff but I will put it off until I get some feedback on what I’ve given you here. Now I’ve got to get cracking on static test loads for Chris Kogelmann. Keep the airspeed up and the dirty side down, guys! Bill Marcy old paper and pencil engineer ------------------------------ End of krnet Digest ***********************************