From: owner-krnet-l-digest@teleport.com[SMTP:owner-krnet-l-digest@teleport.com] Sent: Wednesday, June 03, 1998 5:24 AM To: krnet-l-digest@teleport.com Subject: krnet-l-digest V2 #89 krnet-l-digest Wednesday, June 3 1998 Volume 02 : Number 089 ---------------------------------------------------------------------- Date: Mon, 1 Jun 1998 02:24:24 EDT From: BSHADR@aol.com Subject: Re: KR: wheel fairings? In a message dated 98-05-31 15:08:46 EDT, you write: << Does anybody have a wheel fairing that you've used (or know of) that fits our teeny tires without being excessively large? I'm debating whether I should build them myself or order some from already made. It's not so much the money, but I don't want any huge boats under the wings. >> Mark: Just a thought, but I recall Mike Arnold (AR5) saying the length to dia ratio should be around 3.5 - 3.7 for lowest drag. Maybe some quick measurements and calcs would better help you target the correct way to go. Marty Roberts, who has the floats, has one quick KR, so there may be more too it than just looks. Sharp's Nemisis also has king size wheel pants. He wins every race, last time I heard FWIW. Randy Stein flames to: BSHADR@aol.com Soviet Monica, CA ------------------------------ Date: Sun, 31 May 1998 23:37:54 -0700 From: Micheal Mims Subject: Re: KR: wheel fairings? At 02:24 AM 6/1/98 EDT, you wrote: Marty Roberts, who has the floats, has one quick KR, so there may be more too it than just looks. Sharp's Nemesis also has king size wheel pants. He wins every race, last time I heard FWIW.>>> > Yep this is one place where big really is better! Is it 3.7 or 2.7 X the width for optimum aero advantage? Anyway I did the calcs on my wheels using Mike Arnold's formulas and they are supposed to be 34 inches long. zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Micheal Mims SP290,.. Filling and sanding now! mailto:mikemims@pacbell.net http://www.geocities.com/CapeCanaveral/Hangar/4136/ Irvine Ca Fax 714.856.9417 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ------------------------------ Date: Mon, 1 Jun 1998 07:15:18 EDT From: KR2616TJ@aol.com Subject: Re: KR: Trim Tab In a message dated 98-05-31 21:57:18 EDT, you write: << With my wing tanks and no header tank, and other differences, I won't have the problem with running out of trim, since passengers and fuel will sit very close to the CG of the plane, so I don't figure I'll need a very big trim tab. In fact, with the ground adjustable horizontal stabilizer, I'm very tempted not to bother with it, except for the spring tension setup that we discussed a while back. >> Mark, since I know of the spring tension setup you are referring too I understand where you are coming from. Don't get me wrong here, I understand the trim characteristics inherent in your design. For anyone who is considering not installing some type of elevator trim, or a minimal one, let me relay some experience. For the past month or so I have been doing the test flying of a Kitfox for a local builder. The horizontal stab is ground adjustable with no adjustable trim tab on the elevator. All of the ground testing revealed no bad characteristics. These tests included of course flying the tail, one wheel rollouts and light hops. Upon flying for the first time I had to apply a considerable amount of forward pressure on the stick for level flight. It came in pretty handy for the first three point landing though. We have used up all of the adjustment in the stab and have not fully relieved the forward pressure problem. Over the weekend he was going to install a ground adjustable (bendable) elevator tab. The winds were too high for any flying so we'll have to wait for these storms to settle to see how it works. As light as this plane is (about KR weight), he's never going to be able to get it fully in trim with fuel burnoff, passengers or whatever. Install something whether it is the tab, tension spring or making your entire elevator flight adjustable. Dana Overall Richmond, KY mailto:kr2616tj@aol.com http://www.geocities.com/CapeCanaveral/Hangar/7085/ ------------------------------ Date: Mon, 01 Jun 1998 07:15:14 From: Flesner Subject: Re: KR: Progress halted =========================================== >The insurance adjuster is supposed to be here tomorrow. Funny thing - I was >storing all of those new instruments, radios, GPS, etc for the plane (and >the receipts) in the attic and they must have all blown away. Imagine that! >;-) Seriously though, it makes me glad we paid all of those premiums. > >Toto, I don't think we're in Kansas anymore! >Dean >mailto:drdean@execpc.com > ============================================= Hi Dean, I'm glad to hear you and your family survived !!!! Several people didn't I'm sorry to say. I hope your losses are all temporary. When the insurance adjuster stops by, report you KR parts as anything other than aircraft parts. Call them electronic components or hobby supplies or something. I found out early on in my project that homeowners insurance excludes anything having to do with aircraft. Your project and any related items will need to be covered by aircraft builders insurance or something other than homeowners. I hope you and your neighbors have a speedy recovery from this loss and that it is the last time you experience such a thing!!! Most people , including me, spend more time mourning our losses than counting our blessings!!! It ought to be the other way around. Larry Flesner ------------------------------ Date: Mon, 01 Jun 1998 08:53:29 -0400 From: Donald Reid Subject: Re: KR: wheel fairings? Micheal Mims wrote: > At 02:24 AM 6/1/98 EDT, you wrote: > Sharp's Nemesis also has king size wheel pants. He > wins every race, last time I heard FWIW.>>> > > > Yep this is one place where big really is better! Is it 3.7 or 2.7 X the > width for optimum aero advantage? Anyway I did the calcs on my wheels using > Mike Arnold's formulas and they are supposed to be 34 inches long. > zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz All other things being equal, between 3-1 and 5-1 will work OK. The other way is to get profiles for some of the NACA 6 series symmetrical airfoils. Scale to fit the width. - -- Don Reid Bumpass, Va. mailto:donreid@erols.com KR2XL at http://www.erols.com/donreid/kr_page.htm Ultralights at http://www.erols.com/donreid/usua250.html ------------------------------ Date: Mon, 1 Jun 1998 10:25:49 CST From: "Rex Ellington" Subject: KR: Elevator area G'Day Netters In case it might be of interest to someone, I have spent the last week digging into the elevator area subject. As a result, I am going decrease my elevator area just a tad, because I pick up a bit of area with the counter balances I'll install at the tips. To dig into the area rationale, I talked to people with the most experience as our private strips: one who has built and rebuilt planes from the mid-30s, one who got into the Air Force late in WWII, got Korea and Nam twice and has flown everything from L2s, 51s, B52s, B47s, tankers, hurricane hunters, etc., and qualified for Blackbirds-except for age, an AI who repairs everything old, etc. To distill it down, in performace aircraft (not aerobatic) elevators must be able to control attitude at all speeds from power off stall to full power , as in hards turns for evasive action, whether it be from a Bonanza that doesn't see you to an enemy at 6 o'clock. I consulted a book on WW II a/c and laid graph paper on scaled top views and counting squares came up with the following results for elevator area as percent of horiz. tail: P51, land-based fighter = 37 % Spitfire, " " " = 42 % ME 109, " " " =35% FW 190, " " " = 41 % Mosquito, fighter/bomber = 46% F6F, carrier based fighter = 45 % needed lots of control at very low air speeds on carrier approaches F4U (my love), same = 52% Zero, land-based fighter =27% carrier version came later, also had long fuselage moment arm. RR/KR 2, = approx. 46% By the way, several have heard of the fuss about elevator control sensitivity. One oldster way taught the way to get rid of PIO was to lay your hand flat on top of the stick and control it that way for a while. Then move to stiff fingers and wrist on normal stick grip, then to fingers on stick with elbow resting on thigh. Thank for listening Rex Rex T. Ellington ellingto@gslan.offsys.ou.edu ------------------------------ Date: Mon, 1 Jun 1998 11:35:13 -0700 From: rdewees@juno.com Subject: KR: Re: Project update Hi KR netters.. I know a few of you personally from the Langford gathering and meeting at the Sun and Fun hot dog party but wanted to say that I am finally getting to the point of working on the Kr2 project I have had suspended from the ceiling of my one car garage for 7 months. The workshop was expanded and comopleted last week, and yesterday I got a gang of friends over and we the hauled the KR from the garage out to the street and up the neighbor's drive. We then took 8 feet of his fence down and carefully carried it down the 30 degree hill and into the shop. Big red letter day! For the first time I was able to sit in the fusalage and make motor noises. The wood work is completed , all foam and fiberglass done and canopy and turtle deck completed. I have no idea at all what weights are supposed to be for a stock KR on retracts without canopy or wings attached but was pleased to find only 62 pounds on each main gear and 37 on the tail. The glassed but unfinished wings are 31# each and instrument panel with vacuum is 20#. The jabiru 2 liter 80 hp motor with exhaust but less motor mount is 125# (according to the book) In short I am very encouraged with what I have. It's hard to take somebody else's weight off but I will sure be counting grams and ounces from here on. I added everything I could think of including a 25 pound battery that will be exchanged for a lot lighter one, didn't subtract any weight for the Deil tri gear that will replace the ole retracts and come up with 420#. I obviously can't anticipate weight for completing the glassing, paint,a lot of miscelaneous items like transponder and nav com, but I was really encouraged. I really hope to get it in at about 550 or less but I know It will be hard and I don't know all the problems I will run into that you other netters will be familiar with. One interesting thing I found was that it's a lot bigger in the cockpit that I ever imagined. On paper it didn't look possible to get two 6 footers inside, but have tried it out and it looks doable. The previous builder must have been 6 foot 6 or so as he raised the turtle deck and built a skirt extension around the canopy sides and I have 5 inches head room in the cabin (i'm 6 feet even) and my line of vision is only at the lower edge of the canopy so I will need to sit on pillows if I leave it the way it is. If anybody wants to swap a standard canopy for a heightened one please let me know as I am going to cut this one back to closer to original dimensions and take a tuck in the rear turtle deck or replace it alltogether. Thanks for all the tips in the past and be patient with my inevitable questions that will be showing up here in the future. Ron DeWees Atlanta, Ga rdewees@juno.com ------------------------------ Date: Mon, 01 Jun 1998 13:23:56 -0700 From: Tom Crawford Subject: KR: Alternator noise Now that I am flying with 2 aboard, I have found that I have so much electrical noise coming from the alternator thru the radio, that it prevents the intercom from working. The radio has priority over the intercom, and it thinks that buzzing is a radio transmission. I have verified this by switching off the alternator- the noise dissapears and the intercom works fine. I have tried an automotive noise filter from rodeo snack- 0.5uF capacitor without success, no change in the noise level. Methinks this may be too small? Any electronics gurus out there able to help me out? (Brian, Ross, Tom, etc.) By the way, my wife refuses to fly with me until I get the intercom fixed. Is this a good thing or a bad thing? #:-) Tom Crawford tomc@afn.org Gainesville, FL N262TC ------------------------------ Date: Mon, 1 Jun 1998 21:37:42 EDT From: Genseric@aol.com Subject: KR: Spruce quality I just got done inspecting my spruce shipment and I found one peice with a bow in. It's one of the virtical & rudder spars. I put the 45" long piece next to a straight edge and mesured a 3/16 inch gap. There also seems to be a surface defect running the lenght of the peice. Is this worth sending back for a new peice? Ben Raby Minnesota ------------------------------ Date: Mon, 1 Jun 1998 22:43:16 -0400 (EDT) From: jeroffey@tir.com (jeroffey) Subject: KR: Bahamas Congratulations Mike. John ------------------------------ Date: Mon, 1 Jun 1998 21:39:09 -0800 From: Robert Covington Subject: Re: KR: Spruce quality >I just got done inspecting my spruce shipment and I found one peice with a bow >in. It's one of the virtical & rudder spars. I put the 45" long piece next >to a straight edge and mesured a 3/16 inch gap. There also seems to be a >surface defect running the lenght of the peice. Is this worth sending back >for a new peice? > >Ben Raby >Minnesota One of my same pieces is like that, bow-wise. I don't know what surface defect you are talking about, but if that is tolerable, then use that particular spar piece in the place where it gets the 1/4" doubler behind it to straighten it out. This would be if the bow is an easy lengthwise bend, and not something wierd like bowing that much just in the last foot towards one side. You could just send it back, and not worry about it. ;) Might be the course to take. Robert Covington ------------------------------ Date: Tue, 2 Jun 1998 00:52:33 EDT From: JEHayward@aol.com Subject: Re: KR: Spruce quality In a message dated 6/1/98 7:39:05 PM Mountain Daylight Time, Genseric@aol.com writes: << There also seems to be a surface defect running the lenght of the peice. Is this worth sending back for a new peice? Ben Raby Minnesota >> If they'll pay for the shipping. I had a bad 14' longeron from Wicks when I got my wood shipment.... it had a compression fracture. They told me the replacement piece had to be shipped freight due to the length and charges would be about $40. They said that was why they included an extra 14' piece in the wood kit. Jim Hayward Rapid City, SD ------------------------------ Date: Tue, 2 Jun 1998 08:04:14 EDT From: KR2616TJ@aol.com Subject: Re: KR: Alternator noise-joke In a message dated 98-06-01 13:11:23 EDT, you write: << Any electronics gurus out there able to help me out? (Brian, Ross, Tom, etc.) By the way, my wife refuses to fly with me until I get the intercom fixed. Is this a good thing or a bad thing? #:-) Tom Crawford >> Tom since you haven't got any replies yet you know it may be time "ta do da chickin thang agin" :-)) Dana Overall Richmond, KY mailto:kr2616tj@aol.com http://www.geocities.com/CapeCanaveral/Hangar/7085/ ------------------------------ Date: Tue, 2 Jun 1998 07:56:50 -0400 From: "Griffing, Bruce F (CRD)" Subject: KR: RE: Alternator noise Tom- One disadvantage a composite vehicle has over a metal one is the lack of a good ground. The alternator, by its nature, generates a significant amount of ac you don't want on top of the dc you want to run the plane. The trick is to filter the ac out close to or at the alternator and let the dc run around and do its job. If the ac currents are developing voltages in your ground wiring it can add noise. Another way it can add noise is directly on the 12v side of the circuit. A third possibility radiated noise - a possibility facilitated by the lack of a metal structure in the kr. Since we don't know which of the three it is, I will suggest a few tests. First - sit in your cockpit, run the engine and listen with a few portable radios. Try a few types, with an am radio probably being the most sensitive to radiated interference. If you get none - good - you have eliminated radiated noise as a possible source If you do get some send me your wiring diagram and I'll suggest something else. If radiated noise is not the problem, I would next try putting an RF trap on the alternator. This is a device that consists of a very heavy inductor (all of the alternator current passes through it) and a few capacitors. Get one designed for a car alternator at a ham radio store. Make sure to ground it to the alternator itself. We are trying to make the ac run around this short loop and let the now cleaner dc pass to the airplane. If this doesn't work get back to me and we'll take the next step. Bruce Griffing > From: Tom Crawford[SMTP:tomc@afn.org] > Sent: Monday, June 01, 1998 4:23 PM > To: krnet-l@teleport.com > Subject: KR: Alternator noise > > Now that I am flying with 2 aboard, I have found that I have so much > electrical noise coming from the alternator thru the radio, that it > prevents the intercom from working. The radio has priority over the > intercom, and it thinks that buzzing is a radio transmission. > I have verified this by switching off the alternator- the noise > dissapears and the intercom works fine. > I have tried an automotive noise filter from rodeo snack- 0.5uF > capacitor without success, no change in the noise level. Methinks this > may be too small? > Any electronics gurus out there able to help me out? (Brian, Ross, Tom, > etc.) > > By the way, my wife refuses to fly with me until I get the intercom > fixed. Is this a good thing or a bad thing? #:-) > > Tom Crawford > tomc@afn.org > Gainesville, FL > N262TC > ------------------------------ Date: Tue, 02 Jun 1998 10:38:07 -0500 From: Bobby Muse Subject: Re: KR: Alternator noise At 01:23 PM 6/1/98 -0700, you wrote: >Now that I am flying with 2 aboard, I have found that I have so much >electrical noise coming from the alternator thru the radio, that it >prevents the intercom from working. The radio has priority over the >intercom, and it thinks that buzzing is a radio transmission. >I have verified this by switching off the alternator- the noise >dissapears and the intercom works fine. >I have tried an automotive noise filter from rodeo snack- 0.5uF >capacitor without success, no change in the noise level. Methinks this >may be too small? >Any electronics gurus out there able to help me out? (Brian, Ross, Tom, >etc.) > >By the way, my wife refuses to fly with me until I get the intercom >fixed. Is this a good thing or a bad thing? #:-) > >Tom Crawford >tomc@afn.org >Gainesville, FL >N262TC > Tom, I had the same problem. Besides shielding the alternator, mag and Tach wires, I used a 60uF/65 Volt capacitor on the dc side of the Voltage regulator/rectifier. I purchased it new from a electronic surplus store. I believe it was the type used in power supplies for computers, etc.. It is big...about 2 1/2" x 5", but it works. Bobby Muse(N122B) mailto:bmuse@mindspring.com Wimberly, TX ------------------------------ Date: Tue, 02 Jun 1998 20:31:30 -0500 From: N4DD Subject: Re: KR: wing tip lights/strobes Micheal Mims wrote: > > At 10:07 PM 5/27/98 EDT, you wrote: > > The corvair engine ? never heard of that power > >plant in a kr2......sounds like it would work , just be careful of the weight > >of complete engine assembly. Reliability too! > > Joe > > > > > > There is a KR2 here in Southern California with a corvair engine. He > started off with a reduction unit and the performance was marginal, he > switched to direct drive and said it will do an honest 180mph (verified with > GPS) flat out. That's not to shabby. He thinks he is making between 80 and > 90 hp. Oh yeah,..the extra weight up front made the plane handle better too. > zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz > Micheal Mims > SP290,.. Filling and sanding now! > mailto:mikemims@pacbell.net > http://www.geocities.com/CapeCanaveral/Hangar/4136/ > Irvine Ca > Fax 714.856.9417 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Mike Can you find out what prop he is using? Thanks Jean N4DD ------------------------------ Date: Tue, 02 Jun 1998 19:26:48 -0700 From: Micheal Mims Subject: KR: Corvair Prop At 08:31 PM 6/2/98 -0500, you wrote: >Mike >Can you find out what prop he is using? >Thanks >Jean>> Sure I will ask around, I met this guy only once about 6 months ago. I think I remember him saying he was using a Great American but don't bank on my memory! :o) zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Micheal Mims SP290,.. Filling and sanding now! mailto:mikemims@pacbell.net http://www.geocities.com/CapeCanaveral/Hangar/4136/ Irvine Ca Fax 714.856.9417 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ------------------------------ Date: Tue, 02 Jun 1998 20:36:02 -0700 From: Micheal Mims Subject: KR: Horizontal Stab (was Trim Tab) Anyone ever give any thought to using an airfoil on the stab that flat on top and has camber on the bottom? There are a few aircraft that use that trick. Heck you may even be able to retro a piece of foam to the bottom of an existing stabilizer and sand your airfoil so it produces more tail down force. Also what about adding strakes that are a little negative as far as incidence goes? They could provide some down force I am sure. These are all reasons not to paint my airplane until the test flying is over and I am happy with the way it flies. Its much easier to remove a little primer and add some glass and foam than to wreck a nice paint job! zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Micheal Mims SP290,.. Filling and sanding now! mailto:mikemims@pacbell.net http://www.geocities.com/CapeCanaveral/Hangar/4136/ Irvine Ca Fax 714.856.9417 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ------------------------------ Date: Tue, 2 Jun 1998 23:36:08 EDT From: HAshraf@aol.com Subject: KR: KR Travelling news letter. I am done with the copies. Please let me know who wants it next. Mike, I got your copies. Haris ------------------------------ Date: Tue, 02 Jun 1998 21:59:11 -0600 From: Ron Lee Subject: Re: KR: Horizontal Stab (was Trim Tab) These may be all great ideas but my initial reaction is that they are drag inducing compensations for an "improperly" set horizontal stab. Ron "Not an aero engineer even on KR-Net" Lee At 08:36 PM 6/2/98 -0700, you wrote: >Anyone ever give any thought to using an airfoil on the stab that flat on >top and has camber on the bottom? There are a few aircraft that use that >trick. Heck you may even be able to retro a piece of foam to the bottom of >an existing stabilizer and sand your airfoil so it produces more tail down >force. Also what about adding strakes that are a little negative as far as >incidence goes? They could provide some down force I am sure. These are >all reasons not to paint my airplane until the test flying is over and I am >happy with the way it flies. Its much easier to remove a little primer and >add some glass and foam than to wreck a nice paint job! >zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz >Micheal Mims >SP290,.. Filling and sanding now! >mailto:mikemims@pacbell.net >http://www.geocities.com/CapeCanaveral/Hangar/4136/ >Irvine Ca >Fax 714.856.9417 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > ------------------------------ Date: Tue, 02 Jun 1998 21:20:37 -0700 From: Micheal Mims Subject: Re: KR: Horizontal Stab (was Trim Tab) At 09:59 PM 6/2/98 -0600, you wrote: >These may be all great ideas but my initial reaction is that they are >drag inducing compensations for an "improperly" set horizontal stab. > >Ron "Not an aero engineer even on KR-Net" Lee Yeah I know, but I try to keep ideas floating around for those who are past the construction stage of the stab or even flying their KR and wish to try something different. Trust me there is more than just the stab "improperly" set on this air plane! Besides all the big companies do it. One should'nt give up on a design when there are so many things you can try to fix it. Heck look at a B-1900D next time your at the airport. That thing has crap sticking out all over the place but now it is finally a well behaved airplane. I have read strakes can reduce drag and I can almost guarantee you that an inverted airfoil will create much less drag than a deflected elevator. zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Micheal Mims SP290,.. Filling and sanding now! mailto:mikemims@pacbell.net http://www.geocities.com/CapeCanaveral/Hangar/4136/ Irvine Ca Fax 714.856.9417 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ------------------------------ Date: Wed, 3 Jun 1998 00:59:43 EDT From: DC4FREE@aol.com Subject: Re: KR: KR Travelling news letter. If nobody else has claimed them I'll raise my hand. Don Wright 11904 Meridian Ave So Everett, WA 98208 ------------------------------ Date: Tue, 02 Jun 1998 22:30:40 -0700 From: Micheal Mims Subject: KR: KR gathering video Just watched last years gathering video for the fourth or fifth time and I have to say Video Bob did an outstanding job last year! If any of you new subscribers haven't seen this video you need to buy one. Its fantastic. zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Micheal Mims SP290,.. Filling and sanding now! mailto:mikemims@pacbell.net http://www.geocities.com/CapeCanaveral/Hangar/4136/ Irvine Ca Fax 714.856.9417 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ------------------------------ Date: Tue, 02 Jun 98 11:15:13 CST From: "dboll" Subject: KR: test this is a test to see if this thing is working - ---------- > > Tom- > One disadvantage a composite vehicle has over a metal one is the lac= k > of a good ground. The alternator, by its nature, generates a significa= nt > amount of ac you don't want on top of the dc you want to run the plane. > The trick is to filter the ac out close to or at the alternator and let= the dc > run > around and do its job. If the ac currents are developing voltages in = your > ground > wiring it can add noise. Another way it can add noise is directly on = the 12v > side of > the circuit. A third possibility radiated noise - a possibility facili= tated > by the lack of > a metal structure in the kr. Since we don't know which of the three = it is, I > will suggest > a few tests. First - sit in your cockpit, run the engine and listen = with a > few portable > radios. Try a few types, with an am radio probably being the most sens= itive > to > radiated interference. If you get none - good - you have eliminated = radiated > noise > as a possible source If you do get some send me your wiring diagram > and I'll suggest something else. > If radiated noise is not the problem, I would next try putting an RF = trap > on the alternator. This is a device that consists of a very heavy indu= ctor > (all of > the alternator current passes through it) and a few capacitors. Get = one > designed for > a car alternator at a ham radio store. Make sure to ground it to the > alternator itself. > We are trying to make the ac run around this short loop and let the now > cleaner dc > pass to the airplane. If this doesn't work get back to me and we'll = take the > next step. > Bruce Griffing > > > From: Tom Crawford[SMTP:tomc@afn.org] > > Sent: Monday, June 01, 1998 4:23 PM > > To: krnet-l@teleport.com > > Subject: KR: Alternator noise > > > > Now that I am flying with 2 aboard, I have found that I have so much > > electrical noise coming from the alternator thru the radio, that it > > prevents the intercom from working. The radio has priority over the > > intercom, and it thinks that buzzing is a radio transmission. > > I have verified this by switching off the alternator- the noise > > dissapears and the intercom works fine. > > I have tried an automotive noise filter from rodeo snack- 0.5uF > > capacitor without success, no change in the noise level. Methinks thi= s > > may be too small? > > Any electronics gurus out there able to help me out? (Brian, Ross, = Tom, > > etc.) > > > > By the way, my wife refuses to fly with me until I get the intercom > > fixed. Is this a good thing or a bad thing? #:-) > > > > Tom Crawford > > tomc@afn.org > > Gainesville, FL > > N262TC > > ------------------------------ Date: Tue, 2 Jun 1998 23:13:15 -0700 From: wolfpacks@juno.com (Linda & Paul Martin) Subject: KR: Oregon EAA Fly-In Yikes! It's this weekend, June 6th & 7th, in sunny (I hope) Medford, OR. Free steak BBQ Saturday night for all fly-in pilots and their passengers, Fri. night spaghetti feed, pancake breakfast, burger lunch, FlyMart Young Eagles flights, hourly raffles, free camping, maybe even a sub-standard parts bonfire. Oscar, you up for it? If it's not looking like rain I'll bring my KR2 down to the field. She's not ready to fly yet but looks like she could. The satin look primer sort of hides where I still have to fill & sand. If rain is forecast I'd be happy to bring any of you up to our garage for a look at the plane. Let me know if you're coming to town. We have a nice guest room (dungeon) for any KRNetter who needs a place to stay Sat. night (if I survive the BBQ that is, I'm the cook :-). Paul M. (Martin) Ashland, OR _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866] ------------------------------ Date: Tue, 02 Jun 1998 23:49:57 -0700 From: george bell Subject: Re: KR: KR Travelling news letter. This is a multi-part message in MIME format. - --------------A2E6E9AF82B3FC21D76D65FC Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit I would like to have them next. George Bell 21851 Oceanview Lane Huntington Beach, CA 92646 714-968-2274 HAshraf@aol.com wrote: > I am done with the copies. Please let me know who wants it next. > > Mike, > I got your copies. > > Haris - --------------A2E6E9AF82B3FC21D76D65FC Content-Type: text/x-vcard; charset=us-ascii; name="vcard.vcf" Content-Transfer-Encoding: 7bit Content-Description: Card for George P. Bell Content-Disposition: attachment; filename="vcard.vcf" begin: vcard fn: George P. Bell n: Bell;George P. email;internet: gpbell@pacbell.net x-mozilla-cpt: ;0 x-mozilla-html: FALSE version: 2.1 end: vcard - --------------A2E6E9AF82B3FC21D76D65FC-- ------------------------------ Date: Wed, 3 Jun 1998 06:43:17 EDT From: KR2616TJ@aol.com Subject: Re: KR: KR gathering video In a message dated 98-06-03 01:30:53 EDT, you write: << Just watched last years gathering video for the fourth or fifth time and I have to say Video Bob did an outstanding job last year! If any of you new subscribers haven't seen this video you need to buy one. Its fantastic. zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Micheal Mims >> Met Video Bob at Sun & Fun, he said the forum video will be coming out. He also taped an interview with Tom Crawford. Hey, Tom have you heard from Sport Aviation about your photo proofs yet? Dana Overall Richmond, KY mailto:kr2616tj@aol.com http://www.geocities.com/CapeCanaveral/Hangar/7085/ ------------------------------ Date: Wed, 3 Jun 1998 06:52:31 -0400 From: "Griffing, Bruce F (CRD)" Subject: RE: KR: Alternator noise Tom and Bobby- I don't think the solution Bobby suggested is a good one. From Bobby's description of the capacitor it is a type called an electrolytic. I know from my experience at work that electrolytic capacitors are a source of unreliability in electronic systems. And they are made vulnerable by high temperature operation and vibration. Further, a common failure mode is a short. Do you really want this device across the output terminals of your alternator? I think not. A more robust solution will not be expensive, but may involve some trial and error. I will be glad to help out. If you want more hands on help - seek out a ham radio operator. He/she will be able to help. Bruce > ---------- > From: Bobby Muse[SMTP:bmuse@mindspring.com] > Sent: Tuesday, June 02, 1998 11:38 AM > To: krnet-l@teleport.com > Subject: Re: KR: Alternator noise > > At 01:23 PM 6/1/98 -0700, you wrote: > >Now that I am flying with 2 aboard, I have found that I have so much > >electrical noise coming from the alternator thru the radio, that it > >prevents the intercom from working. The radio has priority over the > >intercom, and it thinks that buzzing is a radio transmission. > >I have verified this by switching off the alternator- the noise > >dissapears and the intercom works fine. > >I have tried an automotive noise filter from rodeo snack- 0.5uF > >capacitor without success, no change in the noise level. Methinks this > >may be too small? > >Any electronics gurus out there able to help me out? (Brian, Ross, Tom, > >etc.) > > > >By the way, my wife refuses to fly with me until I get the intercom > >fixed. Is this a good thing or a bad thing? #:-) > > > >Tom Crawford > >tomc@afn.org > >Gainesville, FL > >N262TC > > > > Tom, I had the same problem. Besides shielding the alternator, mag and > Tach wires, I used a 60uF/65 Volt capacitor on the dc side of the Voltage > regulator/rectifier. I purchased it new from a electronic surplus store. I > believe it was the type used in power supplies for computers, etc.. It is > big...about 2 1/2" x 5", but it works. > > Bobby Muse(N122B) > mailto:bmuse@mindspring.com > Wimberly, TX > > > ------------------------------ Date: Wed, 3 Jun 1998 04:35:18 -0800 From: Robert Covington Subject: RE: KR: Alternator noise >Tom and Bobby- > I don't think the solution Bobby suggested is a good one. From Bobby's >description of the capacitor it is a type called an electrolytic. I know from >my experience at work that electrolytic capacitors are a source of >unreliability >in electronic systems. And they are made vulnerable by high temperature >operation >and vibration. Further, a common failure mode is a short. Do you really >want this >device across the output terminals of your alternator? I think not. A >more robust >solution will not be expensive, but may involve some trial and error. I >will be glad to >help out. If you want more hands on help - seek out a ham radio operator. >He/she will >be able to help. > Bruce The suggestion that Bobby came up with is the one that I would have tried out, and was going to suggest as well. I have experimented with electronics for a long time, and have often used electrolytics for spike absorbtion after conversion to DC. Seems to me that if it shorted, it would just fry the rectifier. Also seems that a fuse could be installed inline with the capacitor, and it would save your alternator and rectifier if the capacitor shorted, if it was going to short at all. Bobby's system has worked fine for a pretty long time, if I am not mistaken (if he installed it when he started flying). I don't know how much heat his gets baked with. Robert Covington ------------------------------ Date: Wed, 3 Jun 1998 07:52:45 -0400 From: "Griffing, Bruce F (CRD)" Subject: RE: KR: Alternator noise Robert- You are correct in saying that a short would just fry the rectifier in the alternator. But you would then be flying on the battery... You are also correct that electrolytics are commonly used for power supplies filters and other energy absorbing applications. But they are not used across automotive alternators. A fuse would reduce the risk of loosing the alternator. My point is that using one in an airplane across the alternator is an unnecessary risk when other more robust solutions exist. Further, they are not expensive. Why not fix it right? Bruce > ---------- > From: Robert Covington[SMTP:t88@primenet.com] > Sent: Wednesday, June 03, 1998 8:35 AM > To: krnet-l@teleport.com > Subject: RE: KR: Alternator noise > > >Tom and Bobby- > > I don't think the solution Bobby suggested is a good one. From Bobby's > >description of the capacitor it is a type called an electrolytic. I know from > >my experience at work that electrolytic capacitors are a source of > >unreliability > >in electronic systems. And they are made vulnerable by high temperature > >operation > >and vibration. Further, a common failure mode is a short. Do you really > >want this > >device across the output terminals of your alternator? I think not. A > >more robust > >solution will not be expensive, but may involve some trial and error. I > >will be glad to > >help out. If you want more hands on help - seek out a ham radio operator. > >He/she will > >be able to help. > > Bruce > > The suggestion that Bobby came up with is the one that I would have tried > out, and was going to suggest as well. I have experimented with electronics > for a long time, and have often used electrolytics for spike absorbtion > after conversion to DC. > > Seems to me that if it shorted, it would just fry the rectifier. Also seems > that a fuse could be installed inline with the capacitor, and it would > save your alternator and rectifier if the capacitor shorted, if it was > going to short at all. > > Bobby's system has worked fine for a pretty long time, if I am not mistaken > (if he installed it when he started flying). I don't know how much heat his > gets baked with. > > Robert Covington > > > ------------------------------ Date: Wed, 03 Jun 1998 06:21:49 -0600 From: Ron Lee Subject: Re: KR: Horizontal Stab (was Trim Tab) As you folks can see by Michael's response to my posting, my lack of engineering sense is obvious! Ron >>These may be all great ideas but my initial reaction is that they are >>drag inducing compensations for an "improperly" set horizontal stab. >> >>Ron "Not an aero engineer even on KR-Net" Lee > >Yeah I know, but I try to keep ideas floating around for those who are past >the construction stage of the stab or even flying their KR and wish to try >something different. Trust me there is more than just the stab "improperly" >set on this air plane! Besides all the big companies do it. One should'nt >give up on a design when there are so many things you can try to fix it. >Heck look at a B-1900D next time your at the airport. That thing has crap >sticking out all over the place but now it is finally a well behaved >airplane. I have read strakes can reduce drag and I can almost guarantee >you that an inverted airfoil will create much less drag than a deflected >elevator. >zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz >Micheal Mims >SP290,.. Filling and sanding now! >mailto:mikemims@pacbell.net >http://www.geocities.com/CapeCanaveral/Hangar/4136/ >Irvine Ca >Fax 714.856.9417 >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > ------------------------------ End of krnet-l-digest V2 #89 ****************************