From - Wed May 21 10:37:21 1997 Return-Path: Majordomo-Owner@lists.teleport.com Received: (from daemon@localhost) by greta.teleport.com (8.8.5/8.7.3) id KAA10094; Wed, 21 May 1997 10:22:03 -0700 (PDT) Date: Wed, 21 May 1997 10:22:03 -0700 (PDT) Message-Id: <199705211722.KAA10094@greta.teleport.com> To: rossy@teleport.com From: Majordomo@teleport.com Subject: Majordomo file: list 'krnet-l' file 'v01.n018' Reply-To: Majordomo@teleport.com X-UIDL: 3849f4472b401de56846cff1b29cd896 X-Mozilla-Status: 0001 Content-Length: 40103 -- From: owner-krnet-l-digest@ (krnet-l-digest) To: krnet-l-digest@lists.teleport.com Subject: krnet-l-digest V1 #18 Reply-To: krnet-l-digest Sender: owner-krnet-l-digest@ Errors-To: owner-krnet-l-digest@ Precedence: bulk krnet-l-digest Sunday, May 18 1997 Volume 01 : Number 018 ---------------------------------------------------------------------- Date: Sun, 18 May 1997 12:20:30 -0500 From: Paul Eberhardt Subject: Re: KR: Current Plans? Right - People seem to be forgetting that 10 lbs of fuel 3" from the cg has the same effect as 1 lb of fuel 30" away. The closer you can get the varying weight of the fuel to the cg, the better off you will be. Paul Eberhardt Micheal Mims wrote: > > At 08:38 PM 5/18/97 +1000, you wrote: > >Okay, but where is the CofG of the fuel? The aircraft's CofG should not > >go past the aft edge of the front spar, the fuel will be between the > >spars according to my plans so the CofG of the fuel will be well aft of > >the required aft CofG. When the nose tips up the fuel will run aft > >anyway consider takeoff, engine dies nose goes up, CofG goes back. Nota > good situation to be in. > > > >However if you like to live dangerously .... > > > > Dangerously? Not hardly, (of course my fuel is in a header tank but if I > had it to do over again I would build wing tanks only) For a couple of > reasons, > > 1) Buy having the fuel in your wings the aircraft becomes more stable as > fuel burns off, and > > 2) if the engine did quit after take off and there was uncontrolled impact > with the ground at least 25 gallons of fuel is out in the wings and not in > your lap! > > In the scenario you mention above, the fuel shifting aft during takeoff > will have negligible effect on the CG moving aft because of the lack of arm. > Also the shape of the tank (airfoil) doesn't allow the total mass to move > aft anyway. (the tank is smaller as you go aft) Do the numbers if you want > > Living Dangerously to me is having a 22 gallon header tank and taking two > 190 pound people on a long X-country and having to land at the other end > tired, and battling with an airplane on short final that is out of nose down > trim and has a greater possibility of ground looping once you touch down! > > Piper, Cessna, Beechcraft, Mooney, and hundreds of others cant be wrong! :-) > > _______________________ > ~~~~~~~~~~~~~~~~~~~~~~ > Micheal Mims > Just Plane Nutts > mailto:mimsmand@ix.netcom.com > > http://www.netcom.com/~mimsmand ------------------------------ Date: Sun, 18 May 1997 10:28:58 -0700 From: Micheal Mims Subject: KR: fuel and CG was(Current Plans?) At 12:20 PM 5/18/97 -0500, you wrote: >Right - >People seem to be forgetting that 10 lbs of fuel 3" from the cg has the >same effect as 1 lb of fuel 30" away. The closer you can get the >varying weight of the fuel to the cg, the better off you will be. > >Paul Eberhardt THANK YOU! :-) _______________________ ~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Sun, 18 May 1997 10:55:39 -0700 From: R Covington Subject: Re: KR: fuel and CG was(Current Plans?) >At 12:20 PM 5/18/97 -0500, you wrote: >>Right - >>People seem to be forgetting that 10 lbs of fuel 3" from the cg has the >>same effect as 1 lb of fuel 30" away. The closer you can get the >>varying weight of the fuel to the cg, the better off you will be. >> >>Paul Eberhardt > > >THANK YOU! :-) > >_______________________ >~~~~~~~~~~~~~~~~~~~~~~ >Micheal Mims Not to mention that even if the wing tanks are a little aft of ideal CG, with a header tank the CG will be moving back a good bit as the fuel is burned, but with the wing tanks, it will be moving forward if anything as it burns. I am not thrilled with header tanks, but I think a nice setup is to have a small header tank (a la Ercoupe) plus two wing tanks that you pump into the header tank to keep things fairly constant CG wise. The header tank can then have about an hour's fuel or so plus a small reserve. If your wing pumps kick off, then you have an hour to put it down before you kick off from a possibly bad deadstick landing. ;) Of course, in that case,if you have done the right thing when you built it, then you can eject the tail and the nose, and surf the wing on down. (I should illustrate that. :) I love that joke about night deadstick landings... " Proceed to land normally, at 50 feet AGL turn on landing light. If you don't like what you see, turn it back off ". :) Robert Covington ------------------------------ Date: Sun, 18 May 1997 14:09:32 -0400 (EDT) From: EagleGator@aol.com Subject: Re: KR: CG and Fuel Tanks, used to be Current Plans? How about some numbers, folks? Opinion is great, but calling the airplane "dangerous" without backup is a little irresponsible without giving us the basis in data for your statement. I've run plenty of numbers myself (long ago and they got lost when I moved) and we all know stablility is an issue we need to deal with, but "dangerous"? This has been way overused, but "Show me the data". And by the way, you have to offload fuel from a 172 to get 4 people in it, why isn't it considered "dangerous"? Know your airplane, plan your CG as you are building and EVERY TIME you fly, and "preparation and awareness" override "dangerous". Sorry for wasting the band width with this, if you have a response, please send it to me personally and let's stop wasting everyone's time.... unless, of course, someone has some data out there..... ;-} Passing the soap box to my right.... Cheers! Rick Junkin EagleGator@aol.com ------------------------------ Date: Sun, 18 May 1997 13:16:05 -0500 From: Paul Eberhardt Subject: Re: KR: fuel and CG was(Current Plans?) Oh Yeah, Another good reason to have fuel in the wings is that it takes that much weight off the spars. The weight of the fuel is supported directly from the wing skins, rather than adding to the load carried by the spars. Paul Eberhardt - "living dangerously" R Covington wrote: > > >At 12:20 PM 5/18/97 -0500, you wrote: > >>Right - > >>People seem to be forgetting that 10 lbs of fuel 3" from the cg has the > >>same effect as 1 lb of fuel 30" away. The closer you can get the > >>varying weight of the fuel to the cg, the better off you will be. > >> > >>Paul Eberhardt > > > > > >THANK YOU! :-) > > > >_______________________ > >~~~~~~~~~~~~~~~~~~~~~~ > >Micheal Mims > > Not to mention that even if the wing tanks are a little aft of ideal CG, > with a header tank the CG will be moving back a good bit as the fuel is > burned, but with the wing tanks, it will be moving forward if anything as > it burns. > > I am not thrilled with header tanks, but I think a nice setup is to have a > small header tank (a la Ercoupe) plus two wing tanks that you pump into the > header tank to keep things fairly constant CG wise. > The header tank can then have about an hour's fuel or so plus a small > reserve. If your wing pumps kick off, then you have an hour to put it down > before you kick off from a possibly bad deadstick landing. ;) > > Of course, in that case,if you have done the right thing when you built it, > then you can eject the tail and the nose, and surf the wing on down. (I > should illustrate that. :) > > I love that joke about night deadstick landings... " Proceed to land > normally, at 50 feet AGL turn on landing light. If you don't like what you > see, turn it back off ". :) > > Robert Covington ------------------------------ Date: Sun, 18 May 1997 14:35:05 -0400 (EDT) From: EagleGator@aol.com Subject: KR: BRS for KR-2S? I'm looking at some of the stability tests (there's that $*%# word again) I'm writing into our test plan, and can only safely go so far without a spin chute or ballistic recovery system. Has anyone looked into using a BRS in their airplane? The weight (I believe about 65 pounds?) may be prohibitive, but there are some flight test regimes I'm not willing to enter without one. Thanks for your help. Cheers! Rick Junkin EagleGator@aol.com ------------------------------ Date: Sun, 18 May 1997 13:28:44 -0600 (MDT) From: Ron Lee Subject: Re: KR: fuel and CG was(Current Plans?) At 13:16 97/5/18 -0500, you wrote: >Oh Yeah, >Another good reason to have fuel in the wings is that it takes that much >weight off the spars. The weight of the fuel is supported directly from >the wing skins, rather than adding to the load carried by the spars. > >Paul Eberhardt - "living dangerously" > Is the normal wing skin sufficiently strong to carry that weight and don't the wing loads get transferred to the spars? Ron ------------------------------ Date: Sun, 18 May 1997 15:47:27 -0400 From: Vince Bozik Subject: Re: KR: fuel and CG was(Current Plans?) Ron Lee wrote: > > At 13:16 97/5/18 -0500, you wrote: > >Oh Yeah, > >Another good reason to have fuel in the wings is that it takes that much > >weight off the spars. The weight of the fuel is supported directly from > >the wing skins, rather than adding to the load carried by the spars. > > > >Paul Eberhardt - "living dangerously" > > > > Is the normal wing skin sufficiently strong to carry that weight and don't > the wing loads get transferred to the spars? > > Ron I think what Paul was saying is: While the fuel is in the stubs/header/etc. and the wings carry the load of the plane "through the spars and Attach Fittings," moving the tanks to the wings will cause the wings to carry the load by themselves(because they provide the lift) Only by themselves, vs. Carrying a load that is located on the other side of the wing attach fittings. Either way the wings are doing work. How's this: Would you rather carry a gallon jug of fuel in your arms - close to your chest, or on the far end of a ten foot pole while you were holding the opposing end. Either way your arms are doing work, but the work and object are more localized. Gee, I hope I didn't make it worse! - -- Vince Bozik - Athens, Georgia Mailto:ICBM@ix.netcom.com ------------------------------ Date: Sun, 18 May 1997 15:57:48 -0400 From: Vince Bozik Subject: Re: KR: fuel and CG was(Current Plans?) Ron Lee wrote: > > At 13:16 97/5/18 -0500, you wrote: > >Oh Yeah, > >Another good reason to have fuel in the wings is that it takes that much > >weight off the spars. The weight of the fuel is supported directly from > >the wing skins, rather than adding to the load carried by the spars. > > > >Paul Eberhardt - "living dangerously" > > > > Is the normal wing skin sufficiently strong to carry that weight and don't > the wing loads get transferred to the spars? > > Ron I think I'll try and butcher this one again. Start with the wing. It provides the lift and carries the rest of the plane.(I'm not taking into consideration the lift provided by the stubs and fuselage, etc.) Wings pull up, pulling up on attach brackets, pulling up on stubs, pulling up on plane, pulling up on your butt. With the fuel in "outboard(detachable part of the)wings" the load is DIRECTLY carried by the wings, vs. wings to fittings to stubs to etc. etc. I think I'm making it worse! Whack Whack... Otherwise, we wouldn't need the wings. Great concept if you want a "KR-CM." (cruise missle) This just takes load off your spars, fittings, etc., cutting out the middlemen, and sticking it directly to the wings. Well, I'd think it would, but then again I'm not all that bright either! This horse might have a couple of good beatings left in him. Anybody, Bueller... - -- Vince Bozik - Athens, Georgia Mailto:ICBM@ix.netcom.com ------------------------------ Date: Sun, 18 May 1997 15:33:19 -0500 From: "Tim \"KitaruSapien\" Tracey" Subject: Re: KR: VW Cam Specs/ PC-Dyno Runs: >Thanks Ross for the cam specs, and if anybody has some other detailed specs on >other parts of the VW aircraft conversions (like carb CFM ratings, etc.) Please >post them, I'd like to refine the model a bit. > >TIA, > >Curt Martin (cmartin@america.com) >Ormond Beach, FL >http://www.america.com/~cmartin > I'm curious Curt, how's the engine life at these R's? I've always been told that even VW's don't appreciate revs in the 4500+ range...but thanks for the info! KitaruSapien > ------------------------------ Date: Sun, 18 May 1997 17:00:41 -0400 (EDT) From: Dennis Ambrose Subject: Re: KR: pitch sens. fix (MAJOR)Snip for the benifit of all!! >Hi, >What's this "particularly with regard to the safety issue of stability" quite a >statement of an non-flyer of a KR2. The KR2 is a stable aircraft, maybe a little >sensitive for pitch control, but this can be remedied quite easily with slight >revision/modification of the flight controls as I did mine. It is a sleek, fast, snip again >to keep my prop tips subsonic. >Adrian VE6AFY >cartera@cuug.ab.ca >http://www.cuug.ab.ca:8001/ > Adrian, for the benefit of the latecommers, what was your solution to your pitch sensitivity concerns and what were the results? SORRY if this is a dead horse, but I'm curious, since you have got (some??) time on the KR. I appreciate your comments. Regards Dennis. ;-D ------------------------------ Date: Sun, 18 May 1997 17:22:02 -0400 From: Carlos Sa Subject: RE: KR: link to MS Word Reader Look into KRlinks, it is there! http://www.axess.com/users/wings/krlinks.htm - ---------- From: Ron Lee[SMTP:ronlee@pcisys.net] Sent: May 17, 1997 10:08 To: krnet-l@teleport.com Subject: Re: KR: KR-2S Test Plan (no archive) > ><< Ok, after much gnashing of teeth, I've got the draft test plan Randy > mentioned uploaded at > > http://members.aol.com/eaglegator/kr2srev2.doc > A link to a Word reader is needed as well. Maybe I am the only person without word. Will check and see if I can find a site with the read only version and report back if I find it Ron begin 600 WINMAIL.DAT M>)\^(A 5`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$-@ 0` M`@````(``@`!!) &`" !```!````# ````,``# #````"P`/#@`````"`?\/ M`0```$<`````````@2L?I+ZC$!F=;@#=`0]4`@````!K``(P`0````4` M``!33510`````!X``S !````%0```&MR;F5T+6Q =&5L97!O``$P`0```!<````G:W)N970M;$!T96QE<&]R M="YC;VTG```"`0LP`0```!H```!33510.DM23D54+4Q 5$5,15!/4E0N0T]- M`````P``.0`````+`$ Z`0````(!]@\!````! ````````,&-0$(@ <`& `` M`$E032Y-:6-R;W-O9G0@36%I;"Y.;W1E`#$(`02 `0`?````4D4Z($M2.B!L M:6YK('1O($U3(%=O0T- +1:2TC`) Q M.3DW,1 P.AM \RS/)\U4;R\/*@LA8"R!V"UL0!/0*]!P%[$@4N,R#RW>=6)J M)=$T+RH,3F4YL!V0.[(M,@7P5 L'D 5 4!KQ(" H;H<=< K $7!I=F4I(A]? M"R@440OR)98^53Y ACS0/"!/:QX`80& %K$$;741<"!G;F%SXSV0&Q @;V8> M< G@'H!Y'@!))SVP0I EL!YR('QD42R M"8!'@@0@=S:0OTH0/0`PX4F@0\ ]4&U$4_LKL3$`<"#!`B ^50/P'H#["& % M0'=.(4_A3@`#$ ,@[Q%P!9 =($6Q(!&P1 `&D/U086,#D2/ 4^%-\ "0$]#_ M4A-$4TYB/E51`SVP$:!&P>=3PQ@0-L(@8@#0'2%48O]4XQX@/>PJT3WL/E\< M&$ -!1 Subject: Re: KR: fuel and CG was(Current Plans?) Ron Lee wrote: > > At 13:16 97/5/18 -0500, you wrote: > >Oh Yeah, > >Another good reason to have fuel in the wings is that it takes that much > >weight off the spars. The weight of the fuel is supported directly from > >the wing skins, rather than adding to the load carried by the spars. > > > >Paul Eberhardt - "living dangerously" > > > > Is the normal wing skin sufficiently strong to carry that weight and don't > the wing loads get transferred to the spars? > > Ron The whole plane is held up by the wing skins. The spars give structure to the skins. With the weight of the fuel already in the wings, it (the fuel's weight) is not added to the weight that is transferred to the wings via the spars and wing attach fittings. This is probably a minor point as I have never heard of a kr's wing coming off, but it can't hurt. Paul Eberhardt ------------------------------ Date: Mon, 19 May 1997 10:17:24 +1000 From: ginnwj Subject: Re: KR: Fuel Tank CofG Micheal Mims wrote: > > At 08:38 PM 5/18/97 +1000, you wrote: > >Okay, but where is the CofG of the fuel? The aircraft's CofG should not > >go past the aft edge of the front spar, the fuel will be between the > >spars according to my plans so the CofG of the fuel will be well aft of > >the required aft CofG. When the nose tips up the fuel will run aft > >anyway consider takeoff, engine dies nose goes up, CofG goes back. Nota > good situation to be in. > > > >However if you like to live dangerously .... > > > > Dangerously? Not hardly, (of course my fuel is in a header tank but if I > had it to do over again I would build wing tanks only) For a couple of > reasons, > > 1) Buy having the fuel in your wings the aircraft becomes more stable as > fuel burns off, and > > 2) if the engine did quit after take off and there was uncontrolled impact > with the ground at least 25 gallons of fuel is out in the wings and not in > your lap! > > In the scenario you mention above, the fuel shifting aft during takeoff > will have negligible effect on the CG moving aft because of the lack of arm. > Also the shape of the tank (airfoil) doesn't allow the total mass to move > aft anyway. (the tank is smaller as you go aft) Do the numbers if you want > > Living Dangerously to me is having a 22 gallon header tank and taking two > 190 pound people on a long X-country and having to land at the other end > tired, and battling with an airplane on short final that is out of nose down > trim and has a greater possibility of ground looping once you touch down! > > Piper, Cessna, Beechcraft, Mooney, and hundreds of others cant be wrong! :-) > > _______________________ > ~~~~~~~~~~~~~~~~~~~~~~ > Micheal Mims > Just Plane Nutts > mailto:mimsmand@ix.netcom.com > > http://www.netcom.com/~mimsmand All of the above is too true especially if you balance the aircraft assuming full wing tanks. However the plans have a fixed engine mount length which will give you CofG problems if you build according to the plans. The logical way to build is to construct the airframe firewall back, retract the wheels (if you have retractables), weigh the airframe with full wing tank fuel (if installed as per plans) and then work out the engine mount length to put the empty CofG where you want it. With the CofG in the right place you will have a stable aircraft. The ideal may be tanks in the leading edge of the outboard wing where at least the fuel would be "out there" in a crash and on the CofG anyway (the RV's have this arrangement). I wonder if anyone has put their fuel in the leading edge? I would prefer an aluminium tank in the LE to avoid problems with leaks. There will be some structural problems to solve although I suspect that the LE will be stronger with the fuel tank installed and wrapped in foam/glass. Getting the fuel out of the fuselage will also reduce the bending moment on the wing attach fittings, possibly make the aircraft more stable etc. The plumbing will be more complex (heavier) and you will still need a header tank (with about two hours of fuel). I am trying to design a suitable LE wing tank at the moment, any suggestions will be welcome. Bill ------------------------------ Date: Mon, 19 May 1997 10:20:43 +1000 From: ginnwj Subject: Re: KR: Wing fuel tank Paul Eberhardt wrote: > > You don't need to fill the section between the spars. I calculate (from > memory, I'm not looking at the plans) roughly 40 gallons of space in > EACH outboard section. I would be happy with about 15 gallons each. > I'll put it as close to the front spar as I can, and put the engine in a > place that makes it all work. This way I'll be most stable when > landing, not like having an empty header tank. > > Paul Eberhardt If you want to have the tanks behind the front spar, why not make it a long narrow tank running the length of the outboard wing, this will reduce the affect on CofG with the tank full and probably make it easier to drain. Tanks in the Leading Edge may be a better option. Bill > > ginnwj wrote: > > > Okay, but where is the CofG of the fuel? The aircraft's CofG should not > > go past the aft edge of the front spar, the fuel will be between the > > spars according to my plans so the CofG of the fuel will be well aft of > > the required aft CofG. When the nose tips up the fuel will run aft > > anyway consider takeoff, engine dies nose goes up, CofG goes back. Not > > a good situation to be in. > > > > However if you like to live dangerously .... ------------------------------ Date: Sun, 18 May 1997 17:23:57 -0700 From: Ross Youngblood Subject: Re: KR: Re: My GPS Wishlist Mike, I don't know if the tripmate will go faster than 99Mph. I saw that the Garmin will do 999Mph. I just figured for $125 plus goodies, it was worth it to try and see how gangly the PC would be for use in the cockpit. I'd rather find this out for $179, then blow $474 and decide I would rather have a handheld unit. I will take it on some rides in a Cessna 152 after I get it and see how it does. -- Ross Micheal Mims wrote: > > At 10:38 PM 5/16/97 -0700, you wrote: > >John, > > Too late... I blew $179 for the Tripmate GPS with Software. It > >uses standard GPS serial codes, so I'm thinking I can hack a driver > >to make it happy with other software. > > > > What did MentorPlus build? I havent a clue. > > Ross will the trip mate track over 99 mph? Most of the cheeper units will > only track about 99 mph and thats it! > > _______________________ > ~~~~~~~~~~~~~~~~~~~~~~ > Micheal Mims > Just Plane Nutts > mailto:mimsmand@ix.netcom.com > > http://www.netcom.com/~mimsmand - -- Ross Youngblood KRNET-L administrator mailto:rossy@teleport.com http://www.teleport.com/~rossy/N541RY.htm ------------------------------ Date: Sun, 18 May 1997 17:26:35 -0700 From: Ross Youngblood Subject: Re: KR: My GPS Wishlist (no archive) Ohh, yea. I forgot about that, however as I recall you get a "BOMB" icon on the screen when a Mac crashes. I haven't used a Mac since I sold my 512K Mac and it's windowing system is far superior to Win95... however the Mac's got messier when they put in the hypercard stuff... R Covington wrote: > > >At 12:48 97/5/15 -0700, you wrote: > >snip > >> We actually are not too far from the Rutan Laptop cockpit, the only > >>problem I see is Windows95. I wouldn't like to get the following > >>response on Final approach: > >> > >> "Altimeter: TASK NOT RESPONDING Code 0x3ffb23s at Address 0x823552" > >> > >> End Task or SHUTDOWN? > >> > >> -- Ross > >> > > > >Easy solution...use windows 3.1 > > > >Ron Lee > > Better solution, use Apple Powerbooks like Rutan does... > > :) > > Robert Covington - -- Ross Youngblood KRNET-L administrator mailto:rossy@teleport.com http://www.teleport.com/~rossy/N541RY.htm ------------------------------ Date: Mon, 19 May 1997 10:28:17 +1000 From: ginnwj Subject: Re: KR: CofG Jeffrey E. Scott wrote: > > On Sun, 18 May 1997 20:40:40 +1000 ginnwj writes: > >> Just plan your CG and mount the engine and heavier accessories > >> accordingly. It's surprisingly simple. In my project, the absolute > >> worst load configuration I can put in it will only go 4 1/2" aft of > >the > >> front of the CG range. That includes using 7 gallon tanks in each > >wing. > >> > >> ---- > >> Jeffrey Scott jscott.pilot@juno.com > >> See construction of KR-2S N1213W at > >> http://fly.hiwaay.net/~langford/kjeffs.html > >> ---- > >The only way to determine your engine mount I agree, however where is > >the empty CofG and will your aircraft stand on the normal wheel position > >or do you have a fix for the forward CofG (nosewheel?) > > > >bill > > > Mine is a taildragger sitting on the Diehl gear although I have 30" legs > rather than the standard 24" legs. My empty CG is 4.4 inches in front of > the forward CG limit. It's certainly light in the tail when empty, but > won't tip over without some help even with the header tank full. The > Diehl gear certainly puts the gear much farther forward than the > retractable. I don't know about Rand's springbar gear. You can see > several pictures of mine at the web site listed below or on John Bryhan's > web site at "http://www.laintra.com/jeb/krpage.htm" if you are interested > in seeing the configuration. > > ---- > Jeffrey Scott jscott.pilot@juno.com > See construction of KR-2S N1213W at > http://fly.hiwaay.net/~langford/kjeffs.html > ---- Thanks for the advice Jeffrey. I enjoyed your photos as well. I would be very interested to know: 1. Where will your loaded CofG be (two people say 170 lbs each, no header tank fuel and full wing tank fuel)? 2. What the load will be on your nosewheel with full header tank of fuel, empty wing tanks and no passengers/freight/missiles etc. 3. Which datum are you referring to, the LE of the inboard wing or another? 4. How heavy your engine + propellor + fittings will be and how long you intend to make your engine mount. Thanks Bill ------------------------------ Date: Mon, 19 May 1997 10:31:24 +1000 From: ginnwj Subject: Re: KR: fuel and CG Micheal Mims wrote: > > At 12:20 PM 5/18/97 -0500, you wrote: > >Right - > >People seem to be forgetting that 10 lbs of fuel 3" from the cg has the > >same effect as 1 lb of fuel 30" away. The closer you can get the > >varying weight of the fuel to the cg, the better off you will be. > > > >Paul Eberhardt > > THANK YOU! :-) > > _______________________ > ~~~~~~~~~~~~~~~~~~~~~~ > Micheal Mims > Just Plane Nutts > mailto:mimsmand@ix.netcom.com > > http://www.netcom.com/~mimsmand The effect of fuel on the CofG will of course vary with the total weight of the aircraft. A very light aircraft will be more affected by a given fuel moment than a heavy aircraft. It pays to work out the effect for the worst case configuration you are expecting. ------------------------------ Date: Sun, 18 May 1997 17:36:11 -0700 From: Ross Youngblood Subject: Re: KR: My GPS Wishlist (no archive) enewbold@sprynet.com wrote: > > Ross wrote: > >>>We actually are not too far from the Rutan Laptop cockpit, the only > >>>problem I see is Windows95. wouldn't like to get the following > >>>response on Final approach: > >>> "Altimeter: TASK NOT RESPONDING Code 0x3ffb23s at Address 0x823552" > >>> End Task or SHUTDOWN? > > Ron Lee wrote: > >> Easy solution...use windows 3.1 > > Ross responded: > >Windows 3.1 has other problems in this area. Windows 95 actually > >has some minor improvements here. > > The solution is to NOT rely only on any Windows product in you cockpit as the > "primary" source of instrumentation. Win 3.1 and Win 95 are far too unstable to > trust in that environment. I'm a professional PC programmer for Bank One, and > all too often these products will sieze up for no obvious reason whatsoever. > Yes, they do *usually* recover after a cold boot (hitting the power switch), but > in my own aircraft I will continue to rely upon more traditional > instrumentation. I use a Trimble handheld GPS as my primary navigation source > and a cheap Garmin as my backup. > > However, my REAL source of navigation are my sectionals! > Ed Newbold > Columbus, OH Ed, I agree that Win95 based products are not robust. However the hardware that runs Win95/Win3.1 is robust and cheap. The trick would be to develop a robust self correcting system based on this cheap hardware and software. Developing a robust OS in itself is too costly. Much research has been done on fault tolerant computing, and I think using this technology, a robust system based on cheap Win95 based PC's could be made to work. However, my panel has all the regular stuff in it today. -- Ross - -- Ross Youngblood KRNET-L administrator mailto:rossy@teleport.com http://www.teleport.com/~rossy/N541RY.htm ------------------------------ Date: Mon, 19 May 1997 10:34:39 +1000 From: ginnwj Subject: Re: KR: fuel and CG was(Current Plans?) R Covington wrote: > > >At 12:20 PM 5/18/97 -0500, you wrote: > >>Right - > >>People seem to be forgetting that 10 lbs of fuel 3" from the cg has the > >>same effect as 1 lb of fuel 30" away. The closer you can get the > >>varying weight of the fuel to the cg, the better off you will be. > >> > >>Paul Eberhardt > > > > > >THANK YOU! :-) > > > >_______________________ > >~~~~~~~~~~~~~~~~~~~~~~ > >Micheal Mims > > Not to mention that even if the wing tanks are a little aft of ideal CG, > with a header tank the CG will be moving back a good bit as the fuel is > burned, but with the wing tanks, it will be moving forward if anything as > it burns. > CofG calculations should really be done assuming the worst case of an empty header tank, that way you won't be heading into an unstable region of the CofG envelope. > I am not thrilled with header tanks, but I think a nice setup is to have a > small header tank (a la Ercoupe) plus two wing tanks that you pump into the > header tank to keep things fairly constant CG wise. > The header tank can then have about an hour's fuel or so plus a small > reserve. If your wing pumps kick off, then you have an hour to put it down > before you kick off from a possibly bad deadstick landing. ;) > > Of course, in that case,if you have done the right thing when you built it, > then you can eject the tail and the nose, and surf the wing on down. (I > should illustrate that. :) > > I love that joke about night deadstick landings... " Proceed to land > normally, at 50 feet AGL turn on landing light. If you don't like what you > see, turn it back off ". :) We need more good advice like this! Thanks Bill > > Robert Covington ------------------------------ Date: Sun, 18 May 1997 18:46:18 -0600 (MDT) From: Ron Lee Subject: Re: KR: Fuel Tank CofG >All of the above is too true especially if you balance the aircraft >assuming full wing tanks. However the plans have a fixed engine mount >length which will give you CofG problems if you build according to the >plans. The logical way to build is to construct the airframe firewall >back, retract the wheels (if you have retractables), weigh the airframe >with full wing tank fuel (if installed as per plans) and then work out >the engine mount length to put the empty CofG where you want it. With >the CofG in the right place you will have a stable aircraft. > This is exactly what some people have suggested and it makes sense. SNIP The plumbing >will be more complex (heavier) and you will still need a header tank >(with about two hours of fuel). > >I am trying to design a suitable LE wing tank at the moment, any >suggestions will be welcome. > >Bill > That depends. A mechanical engine pump and backup electric pumps would eliminate the need for a header tank. Assumes of course that you can mount an engine driven fuel pump. Ron Lee ------------------------------ Date: Sun, 18 May 1997 17:49:33 -0700 From: Ross Youngblood Subject: Re: KR: KR-2S Test Plan RE: Putting the link online. Randy, I will try and get this in... but it may take a few weeks. I'm behind.. BSHADR@aol.com wrote: > > In a message dated 97-05-17 03:18:18 EDT, you write: > > << Ok, after much gnashing of teeth, I've got the draft test plan Randy > mentioned uploaded at > > http://members.aol.com/eaglegator/kr2srev2.doc > > This is a preliminary draft, by no means complete, but I'm posting it as > food > for thought for the folks who are about to enter the flight test phase of > their project. I hope you find it useful. It's in MS Word v6.0, and is > best > viewed in outline mode. > > Cheers! > Rick Junkin > EagleGator@aol.com >> > > Could some of you KR Page guys (Mark, Mike, Ross, Jeff, John, etc.) post a > link from your pages to this. I think the value is too high to not share > this information with everyone. If not as an actual tool, then it still is > very good as an educational medium. > > Thanks > > Randy Stein > BSHADR@aol.com - -- Ross Youngblood KRNET-L administrator mailto:rossy@teleport.com http://www.teleport.com/~rossy/N541RY.htm ------------------------------ Date: Sun, 18 May 1997 19:47:09 -0500 From: Paul Eberhardt Subject: Re: KR: Wing fuel tank ginnwj wrote: > > Paul Eberhardt wrote: > > > > You don't need to fill the section between the spars. I calculate (from > > memory, I'm not looking at the plans) roughly 40 gallons of space in > > EACH outboard section. I would be happy with about 15 gallons each. > > I'll put it as close to the front spar as I can, and put the engine in a > > place that makes it all work. This way I'll be most stable when > > landing, not like having an empty header tank. > > > > Paul Eberhardt > > If you want to have the tanks behind the front spar, why not make it a > long narrow tank running the length of the outboard wing, this will > reduce the affect on CofG with the tank full and probably make it easier > to drain. > > Tanks in the Leading Edge may be a better option. > > Bill That's what I meant by keeping it as close to the spar as I can. A tank right behind the front spar that is 6.5"(avg) tall by 70" long only needs to be 9" deep to get over 16 gallons in it. This is plenty for me. (32 gals, that is). My keen sense of safety (coming from a guy whose first - and almost my last - solo was a 315' hop on a motorcycle) tells me that fuel in the LE is a bad idea. I can count 4 buggered up LE's on our field alone due to deer, and one with a duck print on it. An old (67) crop duster pilot at our field told me that to stay out of trouble when entering a wooded area in a forced landing, you try to get the trees lined up to break off your wings and leave the fuel behind. He said he had used that method and is still around because of it. An older (76) crop duster chimed in, saying that if a guy would be more careful, he wouldn't have such problems. Both pilots retire from crop dusting this summer. ------------------------------ Date: Sun, 18 May 1997 18:04:03 -0700 From: Ross Youngblood Subject: Re: KR: CG and Fuel Tanks EagleGator@aol.com wrote: > > How about some numbers, folks? I have decided to be silent on this until I weigh my aircraft again and do the Weight & BALANCE calculations. If I want to be conservative, I could calulate the moment arm of the fuel at the AFT spar, but I think someplace midway between forward and AFT would be more appropriate. -- Regards Ross - -- Ross Youngblood KRNET-L administrator mailto:rossy@teleport.com http://www.teleport.com/~rossy/N541RY.htm ------------------------------ Date: Sun, 18 May 1997 18:06:40 -0700 From: Ross Youngblood Subject: Re: KR: fuel and CG was(Current Plans?) Paul Eberhardt wrote: > > Oh Yeah, > Another good reason to have fuel in the wings is that it takes that much > weight off the spars. The weight of the fuel is supported directly from > the wing skins, rather than adding to the load carried by the spars. > > Paul Eberhardt - "living dangerously" Well, I don't know about that... the spars might be carrying the load and the skins might be "transferring" the load to the spars. I think you'd have to run the calulations on that under different loadings +/- G's to be sure. -- Ross - -- Ross Youngblood KRNET-L administrator mailto:rossy@teleport.com http://www.teleport.com/~rossy/N541RY.htm ------------------------------ Date: Sun, 18 May 1997 20:14:13 -0500 From: Paul Eberhardt Subject: Re: KR: fuel and CG was(Current Plans?) Yes, you are right. I should have been more specific and said "center spars and wing attach fittings" rather than just "spars". Paul Eberhardt Ross Youngblood wrote: > > Paul Eberhardt wrote: > > > > Oh Yeah, > > Another good reason to have fuel in the wings is that it takes that much > > weight off the spars. The weight of the fuel is supported directly from > > the wing skins, rather than adding to the load carried by the spars. > > > > Paul Eberhardt - "living dangerously" > > Well, > I don't know about that... the spars might be carrying the load and the > skins might be "transferring" the load to the spars. I think you'd have > to run the calulations on that under different loadings +/- G's to be sure. > > -- Ross > > -- > Ross Youngblood > KRNET-L administrator > mailto:rossy@teleport.com > http://www.teleport.com/~rossy/N541RY.htm ------------------------------ Date: Mon, 19 May 1997 11:25:39 +1000 From: ginnwj Subject: Re: KR: fuel and CG Paul Eberhardt wrote: > > Ron Lee wrote: > > > > At 13:16 97/5/18 -0500, you wrote: > > >Oh Yeah, > > >Another good reason to have fuel in the wings is that it takes that much > > >weight off the spars. The weight of the fuel is supported directly from > > >the wing skins, rather than adding to the load carried by the spars. > > > > > >Paul Eberhardt - "living dangerously" > > > > > > > Is the normal wing skin sufficiently strong to carry that weight and don't > > the wing loads get transferred to the spars? > > > > Ron > > The whole plane is held up by the wing skins. The spars give structure > to the skins. With the weight of the fuel already in the wings, it (the > fuel's weight) is not added to the weight that is transferred to the > wings via the spars and wing attach fittings. This is probably a minor > point as I have never heard of a kr's wing coming off, but it can't > hurt. > > Paul Eberhardt My two bob's worth: The tank in the wing is held up by the lower wing skin. With say 40 litres (12 or so US gals I think) you have about 30 lbs of fuel sitting in the tank. Allowing for say a 4 g load (heavy bounced landing or turbulence) you have to design the lower wing skin for 120lb sitting at the worst case say of the middle of the section between the spars. The CofG of the fuel will also be aft of the 25% MAC position so the fuel will contribute to a pitch moment on the wing structure (i.e. twist). Like all these changes, they have to be carefully considered. Over engineering is one option. Are there any aero engineers reading this column? Perhaps they would be interested in looking at the problem. Bill ------------------------------ End of krnet-l-digest V1 #18 ****************************