krnet-l-digest Friday, May 2 1997 Volume 01 : Number 006 ---------------------------------------------------------------------- Date: Wed, 30 Apr 97 19:46:25 GMT From: mathewrz@iafrica.com (Rob Matthews) Subject: Fw: RE: Re: KR: RAF48 incidence, trim - -- Rob Matthews Have a nice day South Africa email mathewrz@iafrica.com - ----------------------------Forwarded Message-------------------------------- > Does Bill have the aerofoil data for the RAF 48? I am sure that if one were > to take a look at Pazmany's Light Aircraft Design book, one would find the > method of calculating incidence angle. My thinking on incidence is; 1) To > generate Cl max at the stall speed of around 55mph without knocking the tail > on the runway. This is vital in a tricycle; in a tail tragger - to produce a > three point landing, I would like a balance between the wing angle of attack > at Cl max and the stall speed. 2) If I had rigged my wing at -2 degrees. The > wing would still stall at Cl max and the related angle of attack BUT can you > imagine the stall attitude from the pilot seat! Dont kid yourselves, 5 > degrees is alot !! In designing my aircraft (not a KR2), I used the > relationship between the normal line of sight from the pilot, the fuselage > attitude and the angle of incidence of the wing at its Cl max, to determine > the rigging angle. > Steve > ---------- > From: SMTP1@K1 - Server@Servers[] > To: > Cc: > Subject: Fw: Re: KR: RAF48 incidence, trim > Date: Monday, April 28, 1997 2:59PM > > > -- > Rob Matthews Have a nice day > South Africa > email mathewrz@iafrica.com > ----------------------------Forwarded Message-------------------------------- > > > smithr wrote: > > > > > > Forgive me for beating this horse. > > > Incidence means little when the wing is flying. And we are only talking > > > about 3.5 degrees anyhow. I suspect that at equilibrium cruise (with 1 > > > person) the KR needs only a fraction of 1 degree, maybe about 0.5 deg to > > > generate enough lift. This means the fuselage is pointing down only 3 > > > degrees. This doesn't seem like much and probably improves visibility. > > > In a landing descent at 3 degrees, the KR fuselage would appear to be > > > pointing down 6 degrees (sounds pretty normal to me). I don't see a > > > problem. > > > I realize that drag is probably not optimized. But the > > > important concerns are whether or not enough trim is available (between > > > a 1 or 2 person load) and the relationship of the wing incidence (3.5 > > > deg) to the horizontal stabilizer incidence (0 deg ) which hopefully > > > stabilizes the plane. Will less than 3.5 decalage stabilize the KR? > > > I will probably lower my incidence very little to 3 deg. > > > Comments anyone? > > > > > > Bob Smith, KR2S , no aerodynamics credentials whatsoever > > > > Bob, another small point on incidence: the root incidence is 3 degrees > > however the tip incidence is of course less. The net result is the > > average incidence is less than 3 degrees. Also the RAF 48 aerofoil has > > a zero lift angle of attack of -2 degrees so the wing/body incidence in > > flight is hard to actually determine theoretically and practically. > > > > The required angle of attack (to support the weight will vary according > > to speed of course so not only has washout, angle of zero lift to be > > considered, but also the speed that you are setting the wing incidence > > for. > > > > An equally important factor is the engine thrust line. If this is not > > set optimally to take into account body angle at cruise and upwash in > > front of the wing, then the efficiency will be reduced affecting cruise > > speed for a given power setting. > > > > Well that's my 2 cents worth. > > > > bill > > > > ------------------------------ Date: Wed, 30 Apr 97 19:46:39 GMT From: mathewrz@iafrica.com (Rob Matthews) Subject: Re: KR: aileron linkage On 30/4/97 11:09AM, in message <1.5.4.32.19970430090913.00686154@pop.mindspring.com>, Bobby Muse wrote: > At 03:12 PM 4/29/97 +0000, you wrote: > Did you mount your rudder pedals on the floor or from the > >shelf? The "new" plans Jeanette has show the rudder cables routed along the > >fuselage sides. Using the nylon blocks or other techniques, isn't there a > >lot of friction when the cables are tensioned? Also, the "construction > >manual" (using the term very loosely) refers indirectly to adding return > >springs to the rudder cables to keep the cables tensioned. Any suggestions > >before I try to re-invent the wheel?> > > > > > FYI, > (1) It doesn't matter if the rudder pedals are mounted on he floor or > the shelf. Mine is mounted on the shelf but the master cyclinders would be > easier to install if the pedals wre mounted on the floor. > (2) The rudder cables are guided by nylon or phenolic(sp) blocks and > used plenolic blocks. The friction is not noticeable. But I would like to > suggest that you consider using Nynaflow tubing to route your cables thru as > used in the Lancair. With the Nynaflow tubing you can make major changes in > the direction of the cable with very little friction. If I would do it over > I would use Nynaflow, but the phenolic works good. > (3) A major reason for the return springs is to keep the rudder > pedals in the proper position when you take your feet off of the pedals. I > used a single spring connected between cables coming from the front of each > rudder pedal, thru pulleys mounted at the inside outboard corners of the > firewall. > > > Bobby Muse > bmuse@mindspring.com > Hi Bobby Please let me know how you mounted your master cylinders, when your pedals are mounted on the shelf. - -- Rob Matthews Have a nice day South Africa email mathewrz@iafrica.com ------------------------------ Date: Wed, 30 Apr 1997 18:23:36 -0700 From: Bill Reents Subject: Re: KR: Fuselage: Covering with 1.45 oz deck cloth At 12:53 AM 4/30/97 -0400, you wrote: >In a message dated 97-04-23 01:09:43 EDT, you write: > >>> Maybe I'm missing something, but if you are covering with glass I would >>> >assume it is for structural purposes. If not, why even bother. >>> >>> Yep your missing something! As we all know the KR doesn't need any >>> strength added! The layer of glass is too aid in sealing the plywood, so >>> don't overlap the dang joints! YOU don't have to use the layer of glass >if >>> you don't want too, but it is recommended by 9 out of 10 who have built >a >>> KR, of course there are some people who insist on not listening to people >>> who have been there! :-) >> >>I haven't met these other 9 folks. The first KR I saw looked terrific, and >>when >>I asked the owner what he did to seal the plywood, he indicated he just used >>primer >>and paint. I think he did seal the staple holes with filler however, thats >>when I >>decided that I didn't need to do anything to the plane. I guess I need to >go >>to >>a KR gathering and meet the 9 other guys. ;) > >To some extent, it depends on where you plan to store the plane, doesn't it? >Around here, I would never be able to afford a hangar, and the climate can be >pretty damp, with lots of rain and some snow in the winter. If a wood plane >is practical at all under such circumstances (and I think it is, with good >varnishing) I would want the fuselage to be watertight even if it got a nick >from a stone, etc, on the paint. To me, this would suggest deck cloth AND a >slight overlap. Guys in So. Cal. and Arizona may think differently. > >If anybody thinks a person without a hangar shouldn't build a wooden plane, >I'd be interested in hearing that discussion, also. > >Mike Taglieri > Hi I used lacquer primer and then (Nit tra stan ), This Fills small pin holes and small depressions .It dries in about 1 hr,depending how thick you spred it. I've used this for many years painting cars. You can buy it at any car paint store,About $6.00 a PT. Can. I dide't use any glass on my KR sides,and they still look good after 20 yrs. Bill Bill Reents http://www.geocities.com/CapeCanaveral/Lab/3050 ------------------------------ Date: Wed, 30 Apr 1997 20:32:02 -0400 (EDT) From: JEHayward@aol.com Subject: Re: KR: Fuselage Widening In a message dated 97-04-29 06:03:17 EDT, you write: << I have both sides of my fuselage built and am considering widening it by a couple inches to have a little more shoulder room. Some say it needs to be wider and others say the standard width is adequate. I am average build and a wider cockpit may be more trouble than it's worth. I would be interested in some comments from those who have "been there, done that" and what they would do if they could do it over again. Thanks, Austin Clark >> Hi Austin... I've widened my KR2-S cockpit 3" at it's widest point on the plans and 1" at the firewall. My wife and I are both about 5'8" and 160lbs. We sit snug in a C-150. I also built the fuselage framework first (sides, bottom, etc) then covered it with the plywood. It was much easier to work with. Jim Hayward ------------------------------ Date: Wed, 30 Apr 1997 17:55:59 -0700 From: David Moore Subject: KR: KR-3 To whom it may concern: A couple weeks ago I remember an article on the KR-3, the idea was abandoned, after Ken Rand's death. Does anyone know what the dimensions of the KR-3 were? I down loaded the article by Ernest Koppe, and was just wondering if anyone knew any of the stats. I know it was an amphib., with a pod mounted engine, but Ken was a nut on keep it light, keep it simple, so I was wondering if he was still using a 60hp VW? It is a good looking aircraft. I would like to see if enough information is availible to recreate this design. David Moore Hesperia,Calif. 92345 Turnkey1@MSCOMM.COM ------------------------------ Date: Wed, 30 Apr 1997 21:01:39 -0400 (EDT) From: JEHayward@aol.com Subject: Re: KR: Fuselage Skin In a message dated 97-04-30 02:21:11 EDT, you write: << Michael, Did you make your scarf joints in the plywood before installation or during installation? I am considering making the scarf joints and letting them cure before installing the skin. Austin Clark >> That's the way I did mine Austin. I traced out the members after getting everything together and left some extra just in case. Good thing since it was off just a bit. The scarf worked out very well tho doing it like that. I just set them on the wall on a couple of nails till I needed them. ------------------------------ Date: Wed, 30 Apr 1997 23:45:12 -0300 From: Raymond Keating Subject: Re: KR: Using AC Switches with DC At 12:53 AM 4/30/97 -0400, you wrote: >I didn't save the post about how electrical switches designed for AC have >less capacity with DC, but today I found a microswitch kicking around on my >desk with capacities listed for both, and I was shocked to discover how MUCH >less capacity they have for DC. This particular switch (Micro micro switch, >Freeport Ill, #V3-1171-D8) has a listed capacity of 10 amps at 125 or 250 >VAC, but only 1/4 amp at 250 VDC. Is this 40-fold decrease typical of all >switches, or just of this type of microswitch? > >Mike Taglieri > > The obvious response to this is that DC voltage is always remarkably lower than AC voltage, as it works on a quite different principle. For all intents and purposes, this is a switch good for almost 6 amps at 12V DC, which is the most practical DC application. It is quite like comparing apples and oranges, when was the last time you saw a piece of electronic equipment that drew 250V DC? My 2cents worth, Ray Keating ================================ Millennium Consulting 4-439 Lutz St. Moncton, NB Canada E1C 5H2 raykeat@auracom.com ================================ ------------------------------ Date: Wed, 30 Apr 1997 23:05:23 -0400 From: Carlos Sa Subject: KR: KRnet *** update *** Good evening, folks! Things have been busy up here! The last of the snow finally melted and we have had some seasonal temperature this week. And today was the last day to file the income tax forms. 4 of them (fed+provincial * me+wife). Fun! :oP But, despite all, I managed to squeeze a few hours to update the archives. I uploaded about half a megabyte. The site is taking a little more than 5 MB at his time! Info for the newcomers: What am I taling about? The KRnet archives. At least, that is how it started. All the postings (with a minimum of pertinent content) are archived and made available to anyone equiped with a web browser. The concept has evolved, and now different kinds of info are available. See below. I even had to change ISP in order to acomodate growth! So, here is the scoop: http://www.axess.com/users/wings/ (my personal homepage) http://www.axess.com/users/wings/krindex.htm (gateway to all things KR. From this page you can reach all other pages in the site) The other pages are: Links - URLs of several sites of interest (KR drivers, builders, parts, info, etc, etc) KR map - a map of N. America allows you to find out where you KR neighbours are (frames support required) KR drivers (in and out of N. America) same info as above, but with no frames. KR archives - KR net postings, in chronological order. Since Jan/96. KR archives, organized - same, but organized in several files according to the contents. KR Online links - pointers to all formats of KR Online available: Word, Acrobat, HTML,... I am hoping I will be able to do some more updating this weekend (the map, some new links, etc). That's all for now, I've taken enough bandwithm and it's almost "Pumpkin Time" on this side of the continent... Cheers Carlos ------------------------------ Date: Wed, 30 Apr 1997 23:22:23 -0500 From: robert k adams Subject: KR: kr colors ross thanks i needed that bit of encouragement as the paint job will cap off allmost a year of rebuilding so i would like to try to make it pretty. havn't had a good flight in it yet since i bought it so am looking forward to getting it airborn soon and hopefully looking good. bob adams mistic@vci.net ------------------------------ Date: Thu, 1 May 1997 00:29:26 -0400 (EDT) From: MikeTnyc@aol.com Subject: Re: KR: Fuselage Widening In a message dated 97-04-29 05:59:14 EDT, you write: >>>>>I have both sides of my fuselage built and am considering widening it by >a couple inches to have a little more shoulder room. Some say it needs to >be wider and others say the standard width is adequate. I am average build >and a wider cockpit may be more trouble than it's worth. I would be >interested in some comments from those who have "been there, done that" and >what they would do if they could do it over again. >>>>> > >I am average build I guess, 5' 11" 185lbs and my wife is 5'11" 130 lbs and >when we both sat in my KR, which is widened 4 inches we fit perfectly. We >both consumed about half of the width and were comfortable. If you do not >plan on using the pre molded parts make it wider! Two men will still be >tight in my KR!! When I got my first ride in a KR2 (standard width) I had >to sit sideways and put my arm around the pilot! If you learned to fly in a >C-150, imagine subtracting about 5 inches from its width and you and your >instructor crawling in! I recall seeing in one of the old (E. Koppe) Newsletters that widening beyond a couple of inches was not recommended because it could adversely affect airflow to the tail. (I'm assuming/guessing that what they were talking about was not normal operations but stalls or spins, but this is my fevered imagination rather than the Newsletter). Now that many wider KR's have been built, does anyone know how truth this turned out to be? Mike Taglieri ------------------------------ Date: Thu, 01 May 1997 00:48:25 EDT From: jscott.pilot@juno.com (Jeffrey E. Scott) Subject: Re: KR: Wood Repair (not a keeper for Archives) >> >Jim, > >I injected epoxy into a split in a longeron by wedging a very small >screwdriver into the split and moved it back and forth to work the epoxy >down into the wood. I clamped it and let it cure. I have more faith in >this repair than a scarfed joint. However, I oriented the longeron so that >the plywood skin will act as a doubler over the repaired area. I think I >would put a doubler over any repaired area if possible even if the only >benefit is piece of mind. > >Austin Clark > Good thinking. Glueing a plywood patch over a longintudinal crack in the grain of a piece of spruce is an FAA accepted standard repair. It's commonly found on the spruce spars of many of the old Champs, Cubs, T-crafts, etc., where they develop longitudinal cracks at the lift strut attach fittings. - ---- Jeffrey Scott jscott.pilot@juno.com See construction of KR-2S N1213W at http://fly.hiwaay.net/~langford/kjeffs.html - ---- ------------------------------ Date: Wed, 30 Apr 1997 21:07:42 -0400 (EDT) From: JEHayward@aol.com Subject: Re: KR: Fire Detector Fuses In a message dated 97-04-28 22:31:09 EDT, you write: << May issue of Kitplanes talks about using thermal fuses to sense fire in the engine compartment. A series of fuses are placed in hotspots and wired in series to a circuit that activates a buzzer or lamp when the circuit opens. ie when a fuse opens the lamp turns on. Anyone have some ideas on what value of fuses to use? I would figure on putting the fuses near fuel lines, pumps, exhaust manifolds, and the battery. >> The thermal fuses I'm familiar with are rated as a temperature in Centigrade that they open. I just replaced one a couple of days ago that was used to keep a crystal oscillator oven from overheating should the electronic temp control go bad which it had. The replacement was gotten from the RCA SK series electronic component line at our electronics supply outlet. Jim Hayward ------------------------------ Date: Thu, 1 May 1997 09:19:16 -0400 (EDT) From: JEHayward@aol.com Subject: Re: KR: Wood Repair (not a keeper for Archives) In a message dated 97-04-30 04:47:07 EDT, you write: << down into the wood. I clamped it and let it cure. I have more faith in this repair than a scarfed joint. However, I oriented the longeron so that the plywood skin will act as a doubler over the repaired area. I think I would put a doubler over any repaired area if possible even if the only benefit is piece of mind. Austin Clark >> I was thinking of using some of the 3/32 plywood on the inside to help plus the skin is already on the outside as you mention. Yep....peace of mind means a lot! Jim Hayward ------------------------------ Date: Thu, 1 May 1997 08:55:20 CDT From: "Rex Ellington" Subject: KR: KR construction G'Day All Now it is time to get serious. 1. Any projects with reasonable amounts of left-over wood or abandonded projects in the very earliest stages within reasonable driving distance of Oklahoma City that are interested in selling?? 2. Am considering a Dragon Fly canopy and wood turtleback over ply bulkheads. Would a 4x4 sheet of ply be enough to cover it?? 3. I believe I have seen reference on krnet to people who are build spread sheets with cost estimate for their entire projects. Any direct references as to how to get copies?? Rex Ellington Rex T. Ellington Science & Public Policy Program Energy Center, 100 E. Boyd Normal OK 73019 ellingto@gslan.offsys.uoknor.edu www.uoknor.edu/spp/ Scroll down to Faculty Associates ------------------------------ Date: Thu, 1 May 1997 12:25:04 -0500 From: "Mark Langford" Subject: Re: KR: Fuselage Widening Austin Clark wrote: > I think I can leave the > fuselage bottom width dimensions to plans. >From experience, I'd say let the bottom go where ever it wants to. Trying to force the boat in yet another direction is sure to yield worisome creaking noises, at best, big long cracks or breaks, at worst. Mark Langford langford@hiwaay.net http://fly.hiwaay.net/~langford ------------------------------ Date: Thu, 01 May 1997 11:54:27 -0400 From: smithr Subject: Re: KR: project update But my plan at the moment is to build a prop shaft that runs off of the flywheel end of the engine, Of course, there's a weight penalty associated with it, and with the Type 4, but longevity is a factor as well. Still going with the Rabbit CIS injection too. Just call me stupid... > > Mark Langford I don't think anyone would call you stupid. And no one would accuse you of being too conservative in your KR modifications either. Thats an interesting KR you're building. Bob Smith ------------------------------ Date: Thu, 01 May 1997 14:24:19 -0700 From: Donald Reid Subject: Re: KR: KR construction Rex Ellington wrote: > > > 2. Am considering a Dragon Fly canopy and wood > turtleback over ply bulkheads. Would a 4x4 sheet > of ply be enough to cover it?? > Just finished glassing the plug for a turtleback mold and I am using a Dragonfly canopy. The arch across the turtleback is approximately 60 inches long at the canopy; however, my canopy sits about two inches higher than most. My guess is that two sheets is more like it. Don Reid donreid@erols.com ------------------------------ Date: Thu, 01 May 1997 14:41:19 -0700 From: "David M. Gargasz" Subject: KR: glyde distance Without power cesna 150 will glyde from 1000' elv. a distance of 15000' under ideal conditions, what will a kr2 do? thanks, Gene Gargasz % dave@erienet.net ------------------------------ Date: Thu, 1 May 1997 18:45:09 -0400 From: Carlos Sa Subject: KR: RE: KR construction Rex, the spreadsheet you are talking about is a contribution of Rick Junkin. You can get a copy of it at http://www.axess.com/users/wings/kronline.htm (Scroll to the bottom of the page). Cheers Carlos - ---------- From: Rex Ellington[SMTP:rellington@ou.edu] Sent: May 1, 1997 09:55 To: krnet-l@teleport.com Subject: KR: KR construction XX SNIP XX 3. I believe I have seen reference on krnet to people who are build spread sheets with cost estimate for their entire projects. Any direct references as to how to get copies?? ------------------------------ Date: Thu, 1 May 1997 17:28:56 -0500 From: "Mark Langford" Subject: Re: KR: Fuselage Widening L.Palaniappan wrote: > Many have widened several inches at the shoulder of the fuse. > Does this involve a corresponding widening of the fuse base? If so > in what proportions? > I just let the bottom assume whatever shape it wanted except for slightly "helping" it to bend in a manner similar to the top, so that the top longerons didn't have to do all of the bending. But I didn't purposely try to keep the bottom dimensions to anything in particular. > Will the length of the fuselage from firewall to tail remain the same, > or become shorter due to increased curvature at the shoulders ? Sure, the tail will get slightly shorter, but the plans are already way off in that view. What's another fraction of an inch? Mark Langford langford@hiwaay.net http://fly.hiwaay.net/~langford ------------------------------ Date: Thu, 1 May 1997 18:01:53 -0600 (MDT) From: Ron Lee Subject: Re: KR: Fuselage Widening At 14:31 97/5/01 -0500, you wrote: >Owen Davies wrote: > >> Does anyone have a good grip on how much difference a wider >> fuselage makes to your cruise and top end? > >Although it could be calculated with some degree of accuracy, my guess is >that the percentage of drag with the width increase is minor, and so would >be the speed decrease. There are lots of other places that attention to >detail will make more difference than the slight increase in wetted area. >And what fun is it if you can't take somebody with you to show them how >cool it is? > >Mark Langford The Wind Tunnel article in the June 97b Kitplanes magazine (page 29) discusses drag and its impact on speed. It might be more valuable to consider its points (as Mark noted) rather than the impact of widening the fuselage a bit. Even IF you lose a knot or two, at least the passenger will not be so sore! Ron Lee ------------------------------ Date: Thu, 1 May 1997 20:03:50 -0400 (EDT) From: JEHayward@aol.com Subject: KR: Fuselage widening After setting the extra 3" of width I'd decided on I epoxied everything and checked it the next evening. Lifting the fuselage frame off the form allowed it to spring back about 2" so I had effectively only an inch increase in width. I questioned our EAA chapter Technical Advisor (a fellow of 70+ years who had been restoring J-3 Cubs for the past 50 or so as well as building a couple of wood planes) told me to wet the bend area with water and let it set. So I placed some aluminum foil on the table under the bend area and wet the top longeron, then wrapped it in a wet strip of torn up towel. This was a very wet cloth and since South Dakota is a bit dry, I wrapped the cloth in aluminum foil. I left this till the next night then removed the foil and cloth and allowed the wood to dry. The following evening I lifted the fuselage off the form and it kept it's shape so well that I could just set it back down on the form. The wood was perfectly dry and the epoxy joints stayed good as well. I suppose I wetted about a 10 to 12 inch length of longeron area. Jim Hayward ------------------------------ Date: Thu, 1 May 1997 20:47:29 -0500 From: "Mark Langford" Subject: KR: stupidity Bob Smith wrote: >I don't think anyone would call you stupid. Hey, who are you callin' NOT stupid? I know stupid when I'm it! Examples? Remember a few weeks ago I reminded everybody to build their copper foil antennas into their vertical stabs? Well yesterday I was admiring the wonderful job I did on my newly finished vertical stab. Know what? NO ANTENNA! Today I fit the rudder to the vertical stab and inserted the bolts. Despite going to the trouble of using my "foolproof" jig/template method to ensure perfect alignment, the top of the rudder was offset from the stabilizer by about 1/16". Doesn't sound like much, but it sure looked funny, and would probably fly that way too. So out comes the dremel tool to cut away the glass and foam, then clean away all the micro which I had "potted" the nuts with. Sure enough, those nuts almost never came out. Then I had to break the hinge off of the spar. Who needs bolts when epoxy works so good? Need more proof? Stay tuned, the weekend's coming up... Mark Langford langford@hiwaay.net http://fly.hiwaay.net/~langford - ---------- > From: smithr > To: krnet-l@teleport.com > Subject: Re: KR: project update > Date: Thursday, May 01, 1997 10:54 AM > > But my plan at the moment is to build a prop shaft that runs off of > the flywheel end of the engine, Of course, there's a weight penalty > associated with it, and with the Type 4, but longevity is a factor as > well. Still going with the Rabbit CIS injection too. Just call me > stupid... > > > > Mark Langford > > I don't think anyone would call you stupid. And no one would accuse you > of being too conservative in your KR modifications either. Thats an > interesting KR you're building. > > Bob Smith ------------------------------ Date: Thu, 1 May 1997 20:21:26 -0600 (MDT) From: Ron Lee Subject: KR: Rotary KR? Page 80 of the June 97 Kitplanes magazine shows a 5 cylinder VW cylinder prototype engine. 75 hp at 2150 rpm and it only weighs 122 pounds. Who will be first to use this engine? Ron ------------------------------ Date: Fri, 2 May 1997 03:47:21 -0400 From: "Curt Martin" Subject: KR: New guy with a question...KR-1 motor glider. Hello, I just subscribed to this list and have an interest in building a KR (if fact, I was eyeing up a partially completed KR-2 in this weeks "Aero Trader"...hmmm... can I scrounge up $4250 in a hurry...hmmmm.:) Actually, while everyone has been discussing widening the KR-2, has anyone lengthened a KR-1 ? Like making a tandem two seat KR-1. This is the direction I have been thinking of going... I'd like to build a two place motor-glider using the KR-1 as the basis (nice thin fuse with longer wings...sounds like a good motor-glider.) I know KR-1 has a long wing conversion for a single seat aircraft...it's stretching the fuse and the wings at the same time that concerns me. Anyone ever heard of something similar being done before? TIA, Curt Martin (cmartin@america.com) Ormond Beach, FL http://www.america.com/~cmartin ------------------------------ Date: Fri, 2 May 1997 07:12:37 -0600 (MDT) From: Ron Lee Subject: Re: KR: KR-1 motor glider. At 03:47 97/5/02 -0400, you wrote: > >Actually, while everyone has been discussing widening the KR-2, has anyone >lengthened a KR-1 ? Like making a tandem two seat KR-1. > One thing that pops up as a red flag is the CG problem. A two place KR can become too tail heavy (aft cg). That is in the side by side configuration. Put the passenger behind and you may really have problems. I believe the Sonerai has a two seat tandem option but the pilot sits in the back seat. The passenger serves to move the cg forward (hopefully not too much). This is the kind of change that you better know what you are doing, since it is major...and will require basically designing a new plane. You have that option Ron Lee >This is the direction I have been thinking of going... I'd like to build a two >place motor-glider using the KR-1 as the basis (nice thin fuse with longer >wings...sounds like a good motor-glider.) I know KR-1 has a long wing >conversion for a single seat aircraft...it's stretching the fuse and the wings >at the same time that concerns me. Anyone ever heard of something similar >being done before? > >TIA, > >Curt Martin (cmartin@america.com) >Ormond Beach, FL >http://www.america.com/~cmartin > > ------------------------------ Date: Fri, 2 May 1997 11:46:20 -0400 (EDT) From: Baleco@aol.com Subject: Re: KR: KR-1 motor glider. In a message dated 97-05-02 09:15:16 EDT, you write: << Sonerai has a two seat tandem option but the pilot sits in the back seat. The passenger serves to move the cg forward (hopefully not too much). >> In the Sonerai the pilot pretty much is sitting just on or just behind the CG. The front seat passenger sits just forward . The back seat pilot's legs are alongside the passenger. It's comfy, compact and pretty much on the CG. We don't have the CG concerns that the KR-2 does. Marty Hammersmith Sonerai N49WE ------------------------------ Date: Fri, 2 May 1997 11:47:02 -0400 From: "Curt Martin" Subject: Re: KR: KR-1 motor glider. > One thing that pops up as a red flag is the CG problem. A two place KR can > become too tail heavy (aft cg). That is in the side by side configuration. > Put the passenger behind and you may really have problems. I believe the > Sonerai has a two seat tandem option but the pilot sits in the back seat. > The passenger serves to move the cg forward (hopefully not too much). I was thinking along the same lines... stretching both directions.. moving the engine forward, and the pilot aft, so the aircraft has a CG is still above the main spar. The passenger would be seated at the same CG point.. increasing the gross weight but not changing the CG position. This is pretty much how most of the 2-place Tandem motor-gliders are built (like The Fournier/Sportavia) by stretching the fuse of a single place design and adding more structure. > This is the kind of change that you better know what you are doing, since > it is major...and will require basically designing a new plane. You have > that option > > Ron Lee As I was saying to Ross Youngblood, I have a few years of training in Aeronautical Engineering, but switched over to Computer Science. I could probably do the design myself, but would be more comfortable with a real engineer reviewing the design and double checking the math. Knowing someone else succeeded in stretching a KR-1 would be a big confidence boost :) Plan B would be to take a KR-2, beef up the center section of the wing, install longer wings, larger tail surfaces, and just live with the increased frontal area of a side-by-side design. If your wondering why I don't just start from scratch, the idea is to keep the cost down by using as much of an existing design as possible. (better to learn by example and have a supply of parts, than to go it alone and have to figure everything out from scratch.) Just out of curiosity, how much design data is included with the KR-2 plans? Any at all? Curt Martin ------------------------------ Date: Fri, 02 May 1997 09:07:59 -0700 From: Micheal Mims Subject: Re: KR: KR-1 motor glider. At 11:46 AM 5/2/97 -0400, you wrote: In the Sonerai the pilot pretty much is sitting just on or >just behind the CG. The front seat passenger sits just forward . The back >seat pilot's legs are alongside the passenger. It's comfy, compact and pretty >much on the CG. We don't have the CG concerns that the KR-2 does. > > Marty Hammersmith > Sonerai N49WE We wouldn't have CG concerns either if the seats were located in the right place! :-) But to answer the guys question, yes there have been tandem KRs built in the past. One concern is the motor glider wings were for a single place, there would be some major redesigning to do if you wanted to carry that extra FAA certified 170 pound passenger. Besides I think the motor glider idea was scraped, and you may have trouble getting Rand to sell you the plans. ________________________________ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Fri, 02 May 1997 09:10:39 -0700 From: Micheal Mims Subject: Re: KR: KR-1 motor glider. At 11:47 AM 5/2/97 -0400, you wrote: >Just out of curiosity, how much design data is included with the KR-2 plans? >Any at all? > NONE!! ________________________________ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Fri, 02 May 97 16:42:05 GMT From: mathewrz@iafrica.com (Rob Matthews) Subject: Fw: RE: Re: KR: Fuselage Widening - -- Rob Matthews Have a nice day South Africa email mathewrz@iafrica.com - ----------------------------Forwarded Message-------------------------------- > ---------- > From: SMTP1@K1 - Server@Servers[] > To: > Cc: > Subject: Fw: Re: KR: Fuselage Widening > Date: Wednesday, April 30, 1997 7:46PM > > Depends on whether you widen the fuselage to the detriment of wing span. If > you just widen the fuse by about an inch or two, I dont suspect a substantial > increase in the drag in reality. Theoretically, > Cdt = Hp * (prop efficiency)*(146,620)/{(Sw)*(Vmax)(Vmax)}. > Cdt = airplane total drag > Sw = wing area > Prop eff. = 0.75 assumed > > Steve > -- > Rob Matthews Have a nice day > South Africa > email mathewrz@iafrica.com > ----------------------------Forwarded Message-------------------------------- > > > Does anyone have a good grip on how much difference a wider > > fuselage makes to your cruise and top end? > > > > Many thanks. > > > > Owen Davies > > > > > ------------------------------ Date: Fri, 02 May 97 16:43:28 GMT From: mathewrz@iafrica.com (Rob Matthews) Subject: Fw: RE: Re: KR: Re: Incidence for retract gear - -- Rob Matthews Have a nice day South Africa email mathewrz@iafrica.com - ----------------------------Forwarded Message-------------------------------- > ---------- > From: SMTP1@K1 - Server@Servers[] > To: > Cc: > Subject: Fw: Re: KR: Re: Incidence for retract gear > Date: Wednesday, April 30, 1997 7:50PM > > > -- > Rob Matthews Have a nice day > South Africa > email mathewrz@iafrica.com > ----------------------------Forwarded Message-------------------------------- > > Hi Dennis > Crosswind conditions are most taxing on a pilot at takeoff and landing. Hence > when close to a runway and at slow speeds, it is reassuring to have excessive > aileron control available to handle the crosswind condition. At low speeds, > ample aileron power during flare can correct momentary trim changes in roll > and yaw. If the aileron is to small in chord or span, then when deflected > downwards they cannot generate enough incr. in Cl to provide the lift > required to raise a low wing. Since the ailerons provide lateral control, it > is obvious why weak ailerons cause a marginal rate of roll and almost > impossible to handle in gusty conditions. > > To be effective in changing wing camber, an aileron should have a chord aft > of the hinge line of 15% to 25% of wing chord (MAC) and a total area ( both > ailerons) of about 7% to 10% of the total wing area. Do the calculations and > satisfy yourselves. I have not yet. > > I dont have to % of MAC or Wing Area for the flaps at hand, because I am not > fitting flaps to my a/c. You may find it in Darryl Stintins Aircraft Design > book or even Pazmany's Light aircraft design book. > > Steve > > > -- > > Rob Matthews Have a nice day > > South Africa > > email mathewrz@iafrica.com > > ----------------------------Forwarded > Message-------------------------------- > > > > > Is it just me or does the aileron on the KR look very long? If you look > at a > > > picture of a lancair you'll notice that the ailerons are short and the > flaps > > > are 2 or 2 1/2 times longer! On the Katana I fly the whole trailing edge > is > > > used and is about 60% flaps and 40% ailerons. Why does the KR have such > > long > > > ailerons and short flaps? > > > > > > Regards Dennis > > > > > > ------------------------------ End of krnet-l-digest V1 #6 ***************************