krnet-l-digest Tuesday, May 6 1997 Volume 01 : Number 009 ---------------------------------------------------------------------- Date: Sun, 4 May 1997 19:46:44 -0400 From: "Curt Martin" Subject: Re: KR: Re: VW Carb placement > Curt, > I have a sheet that shipped with my GPASC cam. It is a SCAT > I always ASSUMED that a cam for TORQUE would be the best choice > where most Cams advertised in HOT VW's are for HIGH RPM operation. > I want good LOW end... which also supports long intake tube runners > (perhaps). > > -- Ross Thanks for the great info.. I'll run 'em through the dyno programs during the week to see what the Torque and HP curves look like. I tend to agree with your assumption... the kind of camshaft that would work best in a direct drive aircraft conversion would be something like a single profile economy/towing cam in the automotive world. (Like a VW Bus/pickup cam.. if such an animal exists.) In theory, if you could have a custom grind camshaft, probably a very short duration one, you could make a VW produce it's peak horsepower at 2500 RPM with a broad power band and high torque, I guessing at 50 peak horsepower @2500 RPM .... hmmm kinda sounds like a Lycoming doesn't it...:) Now it doesn't produce a lot of power compared to high RPM motors, but what it does produce would be all usable and have torque to spin a big prop with a lot of pitch. There are several companies that will custom grind a cam, Crower, Competition Cams, and Crane (though they would need the core or have to make it as a steel cam.) A lot of the others source their cams through these three and resell them under their own brand name. There are probably other custom grinders out there. One of my customers is Crane Cams in Daytona Beach. I know they do make Lycoming and Teledyne/Continental camshafts (at least the Grind Cards are in the system) but they only make one VW Type 1 Camshaft and it's a high RPM performance car cam.. RPM range way outside what we can use for direct drive without resorting to an itty-bitty propeller disk. I've got a lot to learn about VW motors and I know it. I've been reading everything I can find and trying to apply what I learned drag racing GM products to the VW. I wasn't paying much attention before and never realized how much of an aftermarket has grown up around the VW flat four. Looks like you can build the entire motor out of aftermarket parts. What I find really interesting are the aftermarket cases.. aluminum with lots of oiling capacity. I think it's quite possible to build an indestructible (except maybe for prop-strikes) VW powerplant that would behave like it's certified brethren at half the cost. Curt Martin (cmartin@america.com) Ormond Beach, FL http://www.america.com/~cmartin ------------------------------ Date: Sun, 04 May 1997 20:20:37 -0500 From: inet@intellisys.net (brian whatcott) Subject: Re: KR: Fuel System Question At 10:20 AM 5/4/97 -0700, krnet-l@teleport.com wrote: >At 10:55 PM 5/3/97 -0700, you wrote: > Option A might violate the KISS principle and I'm concerned about >>a wing tank becoming unported in a bank if it is a primary fuel source. >>(I don't think flop tubes will help this) I do have the baffles installed per >>plans. (May 86 rev Page 82 Photo#42). >> >> > >If you keep your slip skid ball centered in turns your fuel outlet should >not become unported! >Micheal Mims ...What he said - even if the wing is VERTICAL! Regards brian whatcott Altus OK ------------------------------ Date: Sun, 04 May 1997 19:44:06 -0700 From: Ross Youngblood Subject: Re: KR: feather-fill and progress Peter, Well about 5 years ago I was fat, dumb and happy, and never considered that Feather Fill was polyester over Epoxy. I sprayed it on my tail section. Most of it was sanded off, but I had a wonderfully smooth gray surface after that, well almost. I havent seen any problems with shrinkage or other surface adheasion problems with my horz-stab and elevator over those years. About half of that time was in Arizona, but now the plane is in Oregon, so the moisture has changed with no ill effects. I just sprayed some System III WR-255 primer last weekend and it looks pretty good. I can't gurantee that you won't have problems but it worked for me. I was using DOW Der 330 epoxy from Wicks back then, I'm now using AeroPoxy. I don't think this makes a major difference, but it could. -- Ross Peter Hudson wrote: > > Hi guys, > > First a little progress report. My port outer wing panel is > ready for finish. Wow... a real airplane part in the garage. > After a lot of micro and sanding, I brushed on a coat of epoxy > primer. It looks like there is still a lot more sanding and filling to > go. I'm going to try a patch of micro over the primer in an out of the > way place to see if I can still use it for filling the spots I thought > I'd already finished. > I guess I also need someone to "hold my hand" cause feather fill > scares me. the long-ez plans say use it first, then primer, then paint. > The rule of thumb says epoxy over polyester is okay but not polyester > over epoxy. The epoxy primer I used (Ditzler DT90 carbon black etc.) > says to let cure for XX days before using body fillers (I assume feather > fill fits in there). I brushed on the first coat of primer because that > really fills the pin holes well and it will give me a color warning > before I sand through fibers while sanding and feather-filling. > > I'm worried about the feather fill shrinkage with time and the > feather-fill bond to epoxy (primer or structural). Any comments on these > things before I make a mess? Ross Youngblood ------------------------------ Date: Sun, 04 May 1997 19:49:54 -0700 From: Ross Youngblood Subject: Re: KR: Weight of outer panel Peter, Thanks for the weight statistic, I will weigh my wings soon and post their weights too. I lifted them, and they seem HEAVY, but perhaps 36-40 pounds is about right. -- Ross Peter Hudson wrote: > > Hi again, > > I almost forgot to metion in my feather-fill post. I weighed my outer > panel. > > With micro, without primer,filler,or paint. > With Strobe power supply (1.6 lbs) and wiring (.5 lbs?) > with aileron, balance lead, and hinge > > it weighs 36 lbs. > > I'll let you know how much after filling and painting (I've seen 40 lbs > here a few times so it looks like I'm doing OK.) > > -Peter- Ross Youngblood ------------------------------ Date: Sun, 04 May 1997 21:57:09 -0500 From: ejanssen@chipsnet.com (Janssen Craig) Subject: Re: KR: Parts for sale. At 10:14 AM 5/4/97 -0700, you wrote: >I reached Clyde Lloyd who was selling his KR for $9K. I was going >to take some picutres. It turns out that a mesquite[sp?] bush jumped >out from nowhere and pushed the runway out from under the plane. >... (I'm taking poetic license), actually he had just lifted the >tail up and a gust of wind came up. > > Soo... there is a change. > > Instead of $9K, he is selling the engine (1835cc), new mag, Zenith >carb, instruments and a trailer for $3500. > > Contact: > Clyde LLoyd > Roseburg OR > graphicd@users.wizzards.net > (541) -- I posted the phone number earlier.. this would be the > best way to reach Clyde... I'm looking for it but have > to run.. my daughter is bugging me to go to the pet store > and buy a rabbit... I promised! She reminds me. > Has this aircraft been registered? Can't find it on the AVweb. Also noticed that Clyde is listed as a student pilot with no ratings. Ed Janssen ------------------------------ Date: Sun, 04 May 1997 20:07:55 -0700 From: Ross Youngblood Subject: Re: KR: Fuel System Question brian whatcott wrote: > ...What he said - even if the wing is VERTICAL! > > Regards > brian whatcott > Altus OK And doing my best Homer Simpson Impersonation "DOW!" I'm showing my stupidity again... I'll buy that, now what about side slips. Aren't those nifty to do on Final? I don't want to be thinking about fuel management when I'm in a crosswind landing. I like the overflow tube idea so far. -- Ross Ross Youngblood ------------------------------ Date: Sun, 04 May 1997 20:10:46 -0700 From: Ross Youngblood Subject: Re: KR: Parts for sale. Janssen Craig wrote: > Has this aircraft been registered? Can't find it on the AVweb. Also > noticed that Clyde is listed as a student pilot with no ratings. > > Ed Janssen Hmmm Student pilot in a tail dragger... Hmmm... Well I don't know the answers to those questions, I just thought someone could make out on airplane parts, but Hmmm. Where did you check on the ratings, I thought that was a terrific stroke of genius. Ross Youngblood ------------------------------ Date: Sun, 4 May 1997 21:33:16 -0600 (MDT) From: Ron Lee Subject: KR: Student in taildragger (no archive) > Hmmm Student pilot in a tail dragger... Hmmm... > >Ross Youngblood Actually I started out in a Cessna 140 (tail dragger). I had my near encounter with a shrub tree which I finally cut down. It was about 50' to one side of a dirt strip. That was within my early takeoff path :) Ron ------------------------------ Date: Sun, 4 May 1997 23:49:27 -0400 (EDT) From: EagleGator@aol.com Subject: KR: Progress Report What a weekend! I spent almost all of it fabricating and polishing the hinges for my empenage. I used the oilite bushing method, and man did they turn out nice! Incidentally, for those who are interested in using oilite bushings, the 3/16 ID flanged bushings that Wicks carries (part number FF303-01, 75 cents each) fit into the 1/8" thick hinge material without modification (i.e. the length of the bushing is 3/16", and the flange is 1/16" thick, leaving 1/8" of barrel to fit into the hinge). Current project status: boat complete, ready for glassing; all spars built up and plywood webs scarfed, ready for closing; all empenage wood structures fabricated and ready for hinges and trim servo to be mounted and then ready for foam/glass; tail wheel mounted; Diehl gear on the way, Cleveland wheels/brakes ready to mount; top deck premolds (courtesy of Mike Stearns) enroute and due to arrive early this week; deposit placed on Diehl wing skins for purchase in July (before I spend all my money at Oshkosh.... AGAIN!). If you didn't notice, I've reached a stopping point in each assembly where it reads "epoxy required". Temps are still getting down to 40 at night in my garage (and everywhere else in St Charles, I believe ;-}), still have a few weeks to wait for prime construction weather. I haven't been wasting my time, however, and am in the middle of writing my flight test plan. If anyone has a test plan that they have used or are working on, I'd appreciate a copy. No sense recreating too many more wheels here. OK, time to make the public proclaimation: My goal is to have this aerospace vehicle finished and tested in time to take it to Oshkosh '98. That will be a total of about 25 months from the time I started construction (June '96 ). Yes, before you ask, I am TOTALLY insane, and plan to work day and night (as the day job will permit) to make this come to fruition. Anybody with me??!!! I sure hope so, I'm going to need someone to kick me in the butt when I reach those inevitable periods of disappointment and frustration, and help keep me motivated toward this goal. I'll have to admit that this list has been a monumental source of inspiration and information, thanks to everyone!! Now, back to that test plan.... Cheers! Rick Junkin EagleGator@aol.com ------------------------------ Date: Sun, 4 May 1997 21:39:20 -0700 From: "John Bouyea" Subject: KR: KR2S Missing Data I got my table jigged up today and laid out the first side longerons. Hooray, the spruce is FINALLY out of the box! Before I start cutting the uprights, does anybody know the length of the vertical upright at station "O" or "N"? bou John/Johnna Bouyea johnbouyea@worldnet.att.net ------------------------------ Date: Sun, 4 May 1997 21:44:43 -0700 From: "John Bouyea" Subject: KR: KR2S For Sale in Salem, Oregon John Esch pointed out a KR2S for sale that I've been looking at in Salem, Oregon. I just don't have the funds to drop $6500 right now... Anyhow, it is about to hit the Trade-A-Plane and GAN Flyer. If someone is wanting to buy a KR2S with 40 hours (still no sign-off as far as I can tell), drop me a line and I'll forward details to you. bou John/Johnna Bouyea johnbouyea@worldnet.att.net ------------------------------ Date: Sun, 04 May 1997 22:25:41 -0700 From: Micheal Mims Subject: Re: KR: KR2S Missing Data At 09:39 PM 5/4/97 -0700, you wrote: >I got my table jigged up today and laid out the first side longerons. >Hooray, the spruce is FINALLY out of the box! > >Before I start cutting the uprights, does anybody know the length of the >vertical upright at station "O" or "N"? Gee you mean you want to know the dimensions of something? You builders sure ask a lot! It would be nice if the plans included things as simple as how long key pieces are hu? Actually there isn't an upright at "O" but the distance from the top of the top longeron to the bottom of the lower longeron is somewhere around 11.25 inches. I got this off of sheet number one by measuring the distance against the bottom rib, now hopefully the drawing is to scale! :-) If this information is somewhere in the plans someone please let us know where, because I couldn't find it! And as far as "N" goes you just cut it to fit after setting station "O" at 11.25. and "I" at 19 inches. Have fun! Micheal Mims ------------------------------ Date: Mon, 5 May 1997 02:33:56 -0400 (EDT) From: LVav8r@aol.com Subject: Re: KR: KR2S Missing Data In a message dated 97-05-05 01:31:45 EDT, you write: << it would be nice if the plans included things as simple as how long key pieces are hu? Actually there isn't an upright at "O" but the distance from the top of the top longeron to the bottom of the lower longeron is somewhere around 11.25 inches. I got this off of sheet number one by measuring the distance against the bottom rib, now hopefully the drawing is to scale! :-) If this information is somewhere in the plans someone please let us know where, because I couldn't find it! And as far as "N" goes you just cut it to fit after setting station "O" at 11.25. and "I" at 19 inches. Have fun! >> I'm at this same spot in the construction on my first fuselage side too. I had already cut and fitted a vertical piece for position "O" when I went to look at the drawings and manual. Well I guess I'll just use that piece for good ole gusset blocks. My question is about a piece that looks like it hangs from a line representing the trailing edge of the turtledeck between positions "N" & "O" on drawing "A". A similar piece shows on drawing "1" between "M" & "N". The side panels dont show this to my satisfaction. How have you guys that have already passed this part interpreted this? Do I need to forget about this for now and make it when it's time to install the horizontal stabilizer or do I need to make it now? And to answer your question Mike, KR-2 Drawing #1 shows a dimension of 11.0" at position "N", that should be the same as position "O" on KR-2S Drawing "A". Thanks, Tom Kilgore Las Vegas, NV LVav8r@aol.com ------------------------------ Date: Mon, 05 May 1997 04:00:13 -0500 From: Bobby Muse Subject: Re: KR: aileron linkage At 07:46 PM 4/30/97 GMT, you wrote: >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 > > Well, that was a problem. In an effort to build my KR to be aesy to maintain, I wanted to have easy access to the master cyclinders and of course have the braking system work correctly. I didn't want to have to crawl upsidedown under the forwaed deck to bleed/maintain the brake system. I have about 250 hours on my KR and have never had to do anything(nothing) to my brake system. So maybe I was overly concerned. So what I did was...... (1) made brake pedals using the design as layed out in one the supplement pages of the KR construction manual. (2) mount the master cyclinders on the forward side(center) of the forward spar(I have a fixed gear). The mount was constructed so that the master cyclinder is vertical and the plunger arm is held stationary. (3) attach the bottom(base) of the master cyclinder to a bellcrank and then to the brake pedals via bicycle cables. That's right, bicycle cables, haousing and all. The top quality bicycle cables are aircraft quality and work great. The bellcranks actually lift the masters cyclinders thus creating the pressure to the wheel cyclinders. This may sound a little complex but it is actually quite simple. I hope this helps! Bobby Muse bmuse@mindspring.com ------------------------------ Date: Mon, 05 May 1997 04:58:25 -0500 From: Bobby Muse Subject: Re: KR: Fuselage Widening At 05:28 PM 5/1/97 -0500, you wrote: > > 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. > 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 > > > Mark, Aren't you concerned with any changes in angle of incidence of the horizonal stablizer? Bobby Muse bmuse@mindspring.com ------------------------------ Date: Mon, 05 May 1997 04:58:27 -0500 From: Bobby Muse Subject: Re: KR: Is the turtledeck structural? At 11:15 AM 5/3/97 -0400, you wrote: >> >> The turtledeck,indeed the whole top everything is not structural, so you could make it removeable, some people have done that. >> >> Robert Covington > > Gee, since the weight is already there, it seems that someone would have made it structural, along with a few other mod's, and came up with what could possibly be a lighter and stronger aft section. Any thoughts on the matter?? > >-- >Vince Bozik - Athens, Georgia > Mailto:ICBM@ix.netcom.com > Why? Why would you want make the turtledeck removable? What not a simple access panel? Isn't building a experimental airplane compicated enough? KISS Bobby Muse bmuse@mindspring.com ------------------------------ Date: Mon, 05 May 1997 05:22:11 -0500 From: Bobby Muse Subject: Re: KR:Prop came off At 10:17 PM 5/3/97 -0700, you wrote: >Craig Sellers wrote: >> The hub was a Great Plains Force 1 hub. It appears that the washer which holds the hub on was not hardened - it became dish shaped - this caused the retaining bolt to become loose, the cotter pin then sheared, the bolt holding the hub on became unscrewed and the hub and prop came off the engine. It is VERY VERY important that anyone using a Great Plains force 1 hub make sure that you have a hardened washer holding the hub on. >> This would obviously be a very bad thing to happen in flight. These hubs were purchased about 3 years ago. >> >> Craig Sellers KR2 N34SS > > I have the standard taper hub, not the FORCE-1 hub, and >think I also have a washer behind the retaining bolt, should I inspect this? > > > -- Ross >-- F.Y.I. I have a Revmaster 2100-D. Once during the assembly of the engine, I replaced the soft alumnium peop bolt washer with a hardened washer. After takeoff at 4000' I noticed oil rain-like spots on the windshield. During inspection I found oil leaking past this hardened washer. I replaced the washer with the soft alumniun washer and everything is now fine. Apparently, the soft washer acts as a gasket.Bobby Muse bmuse@mindspring.com ------------------------------ Date: Mon, 05 May 1997 08:39:48 -0700 From: Micheal Mims Subject: Re: KR: KR2S Missing Data At 02:33 AM 5/5/97 -0400, you wrote: And to answer your question Mike, KR-2 Drawing #1 shows a dimension of >11.0" at position "N", that should be the same as position "O" on KR-2S >Drawing "A". Interesting, mine does not show a measurement! Or maybe Im missing it. Where in relation to "N" is it? The aft horizontal spar bulkhead (mounting tab) is installed when you install your horizontal stab. I guess its a custom fit per each KR. Micheal Mims ------------------------------ Date: Mon, 5 May 1997 12:18:22 -0400 (EDT) From: LVav8r@aol.com Subject: Re: KR: KR2S Missing Data In a message dated 97-05-05 11:45:11 EDT, you write: >Interesting, mine does not show a measurement! Or maybe Im missing it. >Where in relation to "N" is it? >> Mike, I guess your data really is missing! My plans show the 11.0" dimension with a vertical arrow right behind the vertical at position "M" and just ahead of the aft horizontal spar bulkhead on KR-2 drawing #1. If you made yours 11.25" instead of 11.0" I don't think I would worry about it, but then I'm definitly not an engineer ( I flunked calculus ). If you measure it on an angle of 7deg from verticle rather than straight verticle it does work out to 11.25". That's using the 4 to 1 scale of the drawings and a compass. Anyway, thanks for the word on the horiz. spar bulkhead. I found a post discussing this from May 3rd AFTER I sent the question, but it still didn't answer my question as well as your response. Tom Kilgore Las Vegas, NV LVav8r@aol.com ------------------------------ Date: Mon, 5 May 1997 14:52:02 -0400 From: "Car Honeywell" Subject: KR: rear spar repair First time post. Pardon any errors. I am rebuilding a KR-2 whaich has seen better days. I am actually pretty close to being finished, less paint. I had a local AME and a few of the EAA types look it over, and for the most part, seems to be pretty good now that most of the work is done, except... When taking the wings on and off, a previous owner was a little too enthusiastic and managed to spear the read spars with the mounting brackets from the outboard sections. Result is a split fracture from the butt end, going back through the mounting hardware bolt area. Main spar is ok. My question: would it be easier to totally remove the old spar and rebuild/remount it, or should I just 12-to-1 slice them and go from there. Any comments welcome. - - Cary Honeywell - C-172-F C-FRRB KR-2 (1977) C-GJMW Email me at cary@storm.ca if you want to be sure I will receive your reply! ------------------------------ Date: Mon, 05 May 1997 13:03:50 -0700 From: Ross Youngblood Subject: Re: KR: Progress Report Rick, Go Rick GO!!! See you at Oshkosh '98! -- Ross ------------------------------ Date: Mon, 05 May 1997 13:09:02 -0700 From: Ross Youngblood Subject: Re: KR: KR2S Missing Data John Bouyea wrote: > > I got my table jigged up today and laid out the first side longerons. > Hooray, the spruce is FINALLY out of the box! > > Before I start cutting the uprights, does anybody know the length of the > vertical upright at station "O" or "N"? > > bou > John/Johnna Bouyea > johnbouyea@worldnet.att.net I believe I measured all the uprights from the plans and multiplied them by the scaling factor to see what I came up with. Most of these I transcribed to my Jig table. I did not trust the drawing to physically be accurate, but I don't recall what second check I did to feel comfortable with the uprights where dimensions were not specified in the drawing. -- Ross ------------------------------ Date: Mon, 05 May 1997 14:16:07 -0700 From: Micheal Mims Subject: Re: KR: KR2S Missing Data At 12:18 PM 5/5/97 -0400, you wrote: >Mike, > I guess your data really is missing! My plans show the 11.0" dimension >with a vertical arrow right behind the vertical at position "M" Well I went home for lunch and checked and sure enough it was there! I don't know how I missed it! I could blame it on the fact that it wasn't in the same location as the other measurements but I wont, I just flat missed it! Good thing the drawing is to scale because if you measure most things on it and multiply four times you get pretty close. ________________________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Micheal Mims Just Plane Nutts mailto:mimsmand@ix.netcom.com http://www.netcom.com/~mimsmand ------------------------------ Date: Sat, 5 Apr 1997 19:05:55 -0700 From: jeb@laintra.com (John Bryhan) Subject: KR: Re: Horiz stab I built horiz stab on table, foam, glass everything, then mounted it on boat, worked fine that way. John jeb@laintra.com http://www.laintra.com/jeb/krpage.htm - ---------- : From: JEHayward@aol.com : To: krnet-l@teleport.com : Subject: KR: Horiz stab : Date: Sunday, May 04, 1997 9:31 AM : : One other question before I get started on the stab.... is it : better/easier to install the spars THEN install the foam or install the : foam/spars as an assembly? ------------------------------ Date: Mon, 5 May 1997 20:43:10 -0500 From: "Mark Langford" Subject: KR: adjustable horizontal stabilizer Bobby Muse wrote: > Mark, Aren't you concerned with any changes in angle of incidence of the horizonal stablizer? Bobby, I made my horizontal stabilizer adjustable, but for various other reasons... Mark Langford langford@hiwaay.net http://fly.hiwaay.net/~langford - ---------- > From: Bobby Muse > To: krnet-l@teleport.com > Subject: Re: KR: Fuselage Widening > Date: Monday, May 05, 1997 4:58 AM > > At 05:28 PM 5/1/97 -0500, you wrote: > > > > 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. > > > 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 > > > > > > > Mark, Aren't you concerned with any changes in angle of incidence of the horizonal stablizer? > > Bobby Muse > bmuse@mindspring.com > > > ------------------------------ Date: Mon, 5 May 1997 20:49:29 -0500 From: "Mark Langford" Subject: KR: Re: Re: Horiz stab Jim Hayward wrote: > : One other question before I get started on the stab.... is it > : better/easier to install the spars THEN install the foam or install the > : foam/spars as an assembly? Jim, I built my horizontal stab and elevator at the same time, to ensure that everything was perfectly aligned. Check http://fly.hiwaay.net/~langford/kht.html for photos and details. Mark Langford langford@hiwaay.net http://fly.hiwaay.net/~langford ------------------------------ Date: Mon, 05 May 1997 14:58:12 -0700 From: Donald Reid Subject: KR: Elevator control failure I spent a number of hours reviewing the archived info since I joined recently (KUDOS to the folks that did all the work), and I noticed one thread that was about the fatal crash that involved a failed elevator control. I got the NTSB report (attached) that I want to share. I also found a related report that involved a failure on the elevator cable. - -- NOV-12-94 at PORTLAND, IN Aircraft: LESSEL KR-2, registration: N95RJ Injuries: 1 Fatal. Witnesses reported seeing the airplane touch down followed by the application of power. The airplane began to veer to the left side of the runway prior to lifting off. The airplane entered what was described as a 80 nose up attitude and then, according to a witness, the nose "fell over" and the airplane descended to impact. Post accident inspection revealed the nose down elevator cable failed at the elevator attach point. Probable Cause The failure of the elevator control cable attach point and the pilot's subsequent inability to control the airplane. AUG-05-93 at OREGON, IL Aircraft: DARST KR-1, registration: N585D Injuries: 1 Fatal. Approximately 12 miles southwest of the airplane's departure airport, witnesses observed the airplane making three erratic excursions in the vertical. Each ended in a stall and fall off, the last to ground collision. Pieces of the elevator control cable were sent to the NTSB metallurgical laboratory for eamination. The lab found a partial separation of the cable in the area of the pulley assembly which resulted in the malfunction of the elevator control cable system. Probable Cause The partial separation of the elevator control cable. In the first case, it sound to me like a failure after touchdown. My guess is either bad workmanship in the original part and/or cables that were too tight. In the second, a good annual and prefight inspections should have found the problem early. In any case, I added two inspection ports under the elevator, one on each side, aligned with the control. I used a hole saw to make the port and a 2.5 mm birch backing ring. Then a round piece of thin plexiglass will be RTV'd in the recess. On the top, I plan on making a fillet shaped piece of plexi for each side. My turtleback will be removeable from the front elevator spar to the cross piece in front of the elevator. I hope this helps someone else. Don Reid donreid@erols.com ------------------------------ Date: Mon, 5 May 1997 22:23:09 -0400 (EDT) From: Dennis Ambrose Subject: Re: KR:Prop came off >Anyone who could post tips on how to check an unused washer for hardness is >encouraged to post. I have the standard taper hub, not the FORCE-1 hub, and >think I also have a washer behind the retaining bolt, should I inspect this? >Or run the engine a bit then check it. > > -- Ross If you take a file to a hardened washer the file won't touch it. A non-hardened washer will file. This is only a crude test but it will reveal a standard washer vs. hardened. The ONLY true qualitive test is the rockwell test, but use it as a starting point. Regards Dennis ------------------------------ Date: Mon, 5 May 1997 23:46:38 CST From: kustom4@juno.com (Rodny E Sebby) Subject: Re: KR: KR2S For Sale in Salem, Oregon Hi Please send me more info on the KR2S. why is he selling at such a reasonable price? Send me additional info if you would.........Thanks Rod Sebby - Kansas City kustom4@juno.com ------------------------------ Date: Tue, 06 May 1997 22:13:46 +1000 From: ginnwj Subject: Re: KR: adjustable horizontal stabilizer Mark Langford wrote: > > Bobby Muse wrote: > > > Mark, Aren't you concerned with any changes in angle of incidence of the > horizonal stablizer? > > Bobby, An adjustable stabilizer would be the ideal way to go, however the structural problems seem to be huge. Most jets have an elevator and automatic stabilizer incidence change system so that the elevator is kept in the neutral position at all times which gives minimum drag and the stick is kept centred. With the stick centred you also have full elevator control available at all times. I have my doubts about the incidence stated in the plans being correct. As the CofG varies so will the position of the stick (elevator) to maintain the correct pitch. In the end with a tail heavy aircraft you are likely to be flying with a displaced stick, preseumably forward. I wonder how the incidence was determined - - relative to the top longerons? this will change depending on the bowing of the fuselage. - - for what CofG position? - - for what speed? However I might be barking up the wrong tree. Bill Ginn > > I made my horizontal stabilizer adjustable, but for various other > reasons... > > Mark Langford > langford@hiwaay.net > http://fly.hiwaay.net/~langford > > ---------- > > From: Bobby Muse > > To: krnet-l@teleport.com > > Subject: Re: KR: Fuselage Widening > > Date: Monday, May 05, 1997 4:58 AM > > > > At 05:28 PM 5/1/97 -0500, you wrote: > > > > > > 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. > > > > > 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 > > > > > > > > > > > Mark, Aren't you concerned with any changes in angle of incidence of the > horizonal stablizer? > > > > Bobby Muse > > bmuse@mindspring.com > > > > > > ------------------------------ Date: Tue, 06 May 1997 09:23:27 -0500 From: Bobby Muse Subject: Re: KR: adjustable horizontal stabilizer At 08:43 PM 5/5/97 -0500, you wrote: >Bobby Muse wrote: > >> Mark, Aren't you concerned with any changes in angle of incidence of the >horizonal stablizer? > > >Bobby, > >I made my horizontal stabilizer adjustable, but for various other >reasons... > >Mark Langford >langford@hiwaay.net >http://fly.hiwaay.net/~langford > Mark, I'm sorry, I meant to ask about the 'angle of attack' of the horizonal stabilizer. For the builder that is considering making changes in the width or length of the KR, shouldn't they be concerned? Bobby Muse bmuse@mindspring.com ------------------------------ Date: Tue, 6 May 1997 10:43:00 CDT From: "Rex Ellington" Subject: (Fwd) KR: Elevator control failure - ------- Forwarded Message Follows ------- 05 May 1997 Donald Reid wrote: I spent a number of hours reviewing the archived info..., and I noticed one thread that was about the fatal crash that involved a failed elevator control. I got the NTSB report (attached) that I want to share. I also found a related report that involved a failure on the elevator cable...... In helping review the large drawings for the KR2S, I have gone back and reviewed notes on my earlier effort. In a couple of places, there were references to binding of the elevator cables. It seems the argument was based on unequal length. When I hooked mine up, I made a change to mitigate the problem, but the final notes seem to have been in a folder that went out the open walls of the garage with the tornado. Since then I have been very interested in going to pushrod control to mitigate this problem and reduce play in the system. There are many examples out there, Dart, Kitfox, etc. They involve one rod from the stick to a walking beam behind the seat, and a second rod from the beam to the elevator control arm. Someone must have done this on a KR, but I'm not aware of it. I hope someone has good drawings, on a proven installation, that could be reviewed and published as an optional part of the plans. Rex Ellington ellingto@ gslan.offsys.uoknor.edu 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: Tue, 6 May 1997 16:12:59 -0500 From: "Mark Langford" Subject: Re: KR: adjustable horizontal stabilizer Bobby Muse wrote: > Mark, I'm sorry, I meant to ask about the 'angle of attack' of the horizonal stabilizer. For the builder >that is considering making changes in the width or length of the KR, shouldn't they be concerned? Bobby, I wouldn't think that changing width would make much difference to air flow over the tail, since the taper of the fuselage is so shallow that flow would stay somewhat attached (although turbulent, I'm sure). The moment caused by the horizontal tail would be directly proportional to any change in length, but I'm not convinced that it is set right in the plans to begin with. And, there have been so many KRs built with so many other variables involved which would have even greater effects. Below is a description of how I made my horizontal stabilizer adjustable. It wasn't that tough, and I feel that it is stronger than the plans call for (but heavier too). The following is small excerpt from my KR2 diatribe "KR Opinions", at http://fly.hiwaay.net/~langford/kopinion.html. If you haven't read it, you might find it interesting. This is probably what Don Reid was referring to when he made his recent comments to Ross about incidence. - -------- My wing incidence is set at 1 degree, with 1.5 degrees of washout. Obviously, the horizontal stabilizer incidence will need to change as well. Since I'm using a new airfoil with a slightly higher pitching moment, at a different incidence, I have made my horizontal stabilizer ground adjustable by adding a 2" x .75" .125" thick aluminum angle on each face of both horizontal spars connecting them to the longerons. This way I can fly the plane at cruise speed, trim it to fly level, and land without disturbing the pitch control. Then, on the ground, the h.s. will be adjusted to reflect what the trim tab is trying to compensate for. By iterating on this procedure, I will eventually arrive at a point where my trim tab will be in line with the rest of the elevator, and my h.s. will be set perfectly for cruise speed with standard pilot and fuel. I will probably epoxy everything in place at that point for safety reasons, assuming no major CG altering modifications are foreseen. - ---------- A detailed photo of my adjustable setup is available from the URL above, or http://fly.hiwaay.net/~langford/kmlht14.jpg. Mark Langford langford@hiwaay.net http://fly.hiwaay.net/~langford - ---------- > From: Bobby Muse > To: krnet-l@teleport.com > Subject: Re: KR: adjustable horizontal stabilizer > Date: Tuesday, May 06, 1997 9:23 AM > > At 08:43 PM 5/5/97 -0500, you wrote: > >Bobby Muse wrote: > > > >> Mark, Aren't you concerned with any changes in angle of incidence of the > >horizonal stablizer? > > > > > >Bobby, > > > >I made my horizontal stabilizer adjustable, but for various other > >reasons... > > > >Mark Langford > >langford@hiwaay.net > >http://fly.hiwaay.net/~langford > > > Mark, I'm sorry, I meant to ask about the 'angle of attack' of the horizonal stabilizer. For the builder that is considering making changes in the width or length of the KR, shouldn't they be concerned? > > Bobby Muse > bmuse@mindspring.com > > > ------------------------------ End of krnet-l-digest V1 #9 ***************************