Brodhead Pietenpol Association

Original Posted By: "TOM STINEMETZE"

Original Posted By: "Bill Church"
Looks more like pitch pocket. I have attached a portion of ANC-19 that might help. You can download more information from ANC-19 about selecting wood at http://www.westcoastpiet.com/construction.htm look for a link to ANC-19 pg 118-126 (9.5mb). About mid page.Chris--------Chris TracySacramento, CAWestCoastPiet.comRead this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/anc_ ... __________

Original Posted By: "ALAN LYSCARS"
Mike,When in doubt, refer to AC 43.13-1B (available here, if you don't have it)http://www.airweb.faa.gov/Regulatory_an ... 43.13>From the photos, it looks like you might have a "pitch pocket", rather thana knot.And according to AC 43.13-1B (Chapter 1, paragraph 1-2):Notes for Table 1-11. Defects Permitted.e. Pitch pockets. Acceptable in center portion of a beam providing they areat least 14 inches apart when theylie in the same growth ring and do not exceed 1-1/2 inches length by 1/8inch width by 1/8 inch depth, and providingthey are not along the projecting portions of I-beams, along the edges ofrectangular or beveled unrouted beams, oralong the edges of the flanges of box beams.>From the photo, it looks like the defect is roughly 2" long, and 3/16" wide,and probably deeper than 1/8" (hard to tell). So it appears to be outside ofacceptable limits.Since this is going to be the main structural component of your wings, Idon't think I would take a chance on it. What's the cost of a new spar -$100 or so? I would buy a new piece. You will be able to use the board forother parts. The wood looks nice. What does the end grain look like?Bill C.________________________________________________________________________________Date: Wed, 12 Nov 2008 17:24:21 -0500

Original Posted By: "walt"
Tom,Just curious, but why are you asking whether a trim system is necessaryAFTER you have designed and built one? Since there is none in the plans, youmust have felt it to be necessary.In any case, from what I have read, a trim system really only gets used ifyou have your fuel tank in the fuselage, rather than the wing. As the weightof the fuel (located ahead of the CG) is depleted, the CG shifts, and havinga flight-adjustable elevator trim helps to ease the stick forces required tocompensate for the shift in weight. When the fuel is in the wing, the weightis centered pretty much on the CG, so, once the plane is trimmed properly,fuel burn does not have a major effect.As with all "added features" on the Pietenpol, a trim system comes with a"price" - added weight.I haven't yet heard a Pietenpol builder regret making his plane too light.Bill C. ________________________________________________________________________________Date: Wed, 12 Nov 2008 17:59:59 -0500

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Where did you get the head? I'm at the point where I'm thinking to get anengine built with some "improvements".Bob -----Original Message-----

Original Posted By: "Ryan Mueller"

Original Posted By: Bill Church
I don't like it either, even though fir is stronger than spruce.Is this the one with the bow?In any case a half inch of bow is outside the possibility ofstraightening it by cutting it straight. Since you've essentialygot 1/4" of extra depth to the material the spar end will stillbe 1/4" bowed on the opposite edge albeit for only one and ahalf feet. Then again from the last rib it's 4" cut down to thewing tip bow so the bowed in part will only be 14" with a depthof 1/8" at the last rib. You'd have to watch the newly createdrunout too.Also the grain runout appears to be on the edge of acceptabilityin the photo.And we still don't know what the end grain angle is.Clif"Trifles make perfection, and perfection is no trifle." (Michelangelo) ----- Original Message -----

Original Posted By: Jeff Boatright
Mike,-If you really want to "repair"-the pitch pocket you can always cut it out and do a proper splice joint in your spar. Again, refer to AC 43.13-1B Chapter 1 for details.-But, in my opinion (as always, take it or leave it) you're talking about spending maybe two hundred bucks more for a new piece of wood that's going to be holding you (and maybe somebody you care about) up in the air.-That's most likely to be-less than 2% of the cost of the complete airplane.-And you will still be able to use the "defective" board for other parts, so the net cost to you is much less.-Bill C.-________________________________________________________________________________Date: Thu, 13 Nov 2008 10:58:08 -0500

Original Posted By: "Ryan Mueller"
Mike,-If you really want to "repair"-the pitch pocket you can always cut it out and do a proper splice joint in your spar. Again, refer to AC 43.13-1B Chapter 1 for details.-But, in my opinion (as always, take it or leave it) you're talking about spending maybe two hundred bucks more for a new piece of wood that's going to be holding you (and maybe somebody you care about) up in the air.-That's most likely to be-less than 2% of the cost of the complete airplane.-And you will still be able to use the "defective" board for other parts, so the net cost to you is much less.-Bill C.-________________________________________________________________________________Date: Thu, 13 Nov 2008 10:43:07 -0600

Original Posted By: Bill Church
One of the two repairs listed for broken solid spars is to cut out the failure and splice in a good piece of wood. This is the same repair that you would have to execute to remove a pitch pocket. The other method is to use reinforcing plates of spruce or ply on both sides of the spar to restore the shear strength lost to a longitudinal crack, but that is a repair for a crack and not an open void such as a pitch pocket. There must be a enough of a difference in the loss of integrity and strength to a void than a crack to make it applicable in one case, and not in the other.RyanOn Thu, Nov 13, 2008 at 9:39 AM, Michael Perez wrote:I agree with you Bill. I plan on buying a new spar and use this defective one for other stock. I just found it odd that there was no repairs noted for such a thing, yet if the spar is broke, you can fix it. Doesn't make sense to me.--- On Thu, 11/13/08, Bill Church wrote:

Original Posted By: slowbilder(at)comcast.net
Except for the fact that you now have a larger void, and if the void is the issuein the first place you have only exacerbated the problem. True, it is a filledvoid, but a void nonetheless. I don't know enough about the issue to say whether or not that would be acceptable.If you were to perform such a repair I would think your DAR is going to wantdata to back it up. That is not an acceptable spar repair according to AC43.13, so that may be a problem. Off to work for the day. Have a good one,RyanOn Thu, Nov 13, 2008 at 10:24 AM, Michael Perez wrote:I was just looking at that Ryan. I am wondering if I can mill out the pocket, inserta plug with epoxy and the maybe add the plates.________________________________________________________________________________Date: Thu, 13 Nov 2008 18:41:35 +0000 (UTC)

Original Posted By: Michael Perez

Original Posted By: AMsafetyC(at)aol.com
Walt and others have it exactly right... if you have your fuel in the wing,elevator trim really isn't necessary. 41CC has the fuel in the nose and Ido notice a clear difference in stick position and pressure in cruise withfull fuel and part fuel. I installed a trim system in the airplane but I'vefound that I never adjust it after I initially set it... basically it uses abungee on the top arm ofthe elevator bellcrank behind the pilot's seat to make the elevator "light"(applies nose-up trim), and that has decreased the difference in stick feelwhen the fuel tank is full but it's still noticeable. Total weight of thetrim system is probably half a pound. As others have noted, the only timeyou really notice it is on long flights (over an hour or so). Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________

Original Posted By: Michael Perez
Subject: Re: Pietenpol-List: Elevator TrimI may be using a dual tank set up, one in the wings and one in front, now is a good time for me to be thinking about it so if anyone has pics to share on the best design and installation I would appreciate seeing them. Along with any type of description all suggestions are appreciated along with any suggested improvements in the design to make it most effective, reliable and easyto use.I may abandon the entire idea but would really like to see what goes into a trim system for a Piet before I make that decision.Thanks to all that participateJohnIn a message dated 11/13/2008 8:53:58 A.M. Eastern Standard Time, taildrags(at)hotmail.com writes:--> Pietenpol-List message posted by: Oscar Zuniga Walt and others have it exactly right... if you have your fuel in the wing,elevator trim really isn't necessary. 41CC has the fuel in the nose and Ido notice a clear difference in stick position and pressure in cruise withfull fuel and part fuel. I installed a trim system in the airplane but I'vefound that I never adjust it after I initially set it... basically it uses abungee on the top arm ofthe elevator bellcrank behind the pilot's seat to make the elevator "light"(applies nose-up trim), and that has decreased the difference in stick feelwhen the fuel tank is full but it's still noticeable. Total weight of thetrim system is probably half a pound. As others have noted, the only timeyou really notice it is on long flights (over an hour or so). Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net**************Get the Moviefone Toolbar. Showtimes, theaters, movie news & p://toolbar.aol.com/moviefone/download.html?ncid=emlcntusdown00000001)________________________________________________________________________________Date: Thu, 13 Nov 2008 06:35:41 -0800 (PST)

Original Posted By: Michael Perez
Michael:I have heard that there are those who have made their own spar stock up by laminating strips but I don't know about the criteria, so I suppose if you stock was tall enough and the grain was 100% straight throughout otherwise, you could run it through the table saw and rip out the offending 1/4 inch through the whole length and re-glue. But then you may as well order an other good length and rip that one with the pitch pocket up for cap strip. Don't know what the etiquette is on gussets but that may be an option as well if it is located in the right place and after you get your ribs on.Michael in Maine ----- Original Message -----

Original Posted By: Michael Perez
Mike,If you really want to "repair" the pitch pocket you can always cut it outand do a proper splice joint in your spar. Again, refer to AC 43.13-1BChapter 1 for details.But, in my opinion (as always, take it or leave it) you're talking aboutspending maybe two hundred bucks more for a new piece of wood that's goingto be holding you (and maybe somebody you care about) up in the air. That'smost likely to be less than 2% of the cost of the complete airplane. And youwill still be able to use the "defective" board for other parts, so the netcost to you is much less.Bill C. ________________________________________________________________________________Date: Thu, 13 Nov 2008 07:39:02 -0800 (PST)

Original Posted By: "Ryan Mueller"

Original Posted By: Michael Perez

Original Posted By: "Michael Silvius"
Jeff wrote->Given that you set it and forget it, would a trim tab not do the same for you?Yes. It will trim for a given configuration, which is pretty much what myadjustable setup does since I only set it once and never change it. Somehave preferred not to have fixed tabs on their control surfaces forappearance purposes but my airplane already has a tab on the rudder so Iwouldn't have cared. I thought I would like the adjustability but have not usedit much.>I would still like an in-flight trim solution, but I'd like to know your thoughts.I've seen various ones, including Mike Cuy's simple biasing spring setup with aleverunder the pilot's seat. Another one that I've seen is a lot more elaborate, withatrim wheel, bicycle chain segment, and cables/pulleys. I like trim wheels andit'sprobably what most of us are used to (except those who, like me, learned to trimbycranking a window handle either overhead or on the side of the cockpit). Thereis alsoa very simple system used in the Great Lakes and others, where you tug forwardor aft ona cable that runs along the side of the cockpit(s) against a friction device. I don'tthink I've seen one on a Piet but it could work. The beauty of that one is thatit canbe run to both cockpits with very little extra effort.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________

Original Posted By: slowbilder(at)comcast.net
send him one of these:http://www.flycorvair.com/6522223.jpg ----- Original Message -----

Original Posted By: Michael Perez
Lay it flat and run a tight string from end to end parallel tothe straightest section near the edge.Clif ----- Original Message -----

Original Posted By: "Marc Dumay"
Mike,Are you coming up with these ideas just to get a reaction out of people?If I read your question correctly, you are proposing carving recesses into thespar, so that the brackets that attach the lift struts to the wing will sit flushwith the faces of the spar. Your question begs another question...Why?Assuming that you had a solid 3/4" spar, and you routed a 1/8" deep slot for thefitting on each side, you will have effectively weakened your spar by 33%. Andthe benefit of this action would be... nothing.I have no idea why you would want the fittings to be flush with the faces of thespar. The recesses would do nothing other than weaken the spar. The epoxy bondbetween the steel strap and the wood can not be relied on to carry a load.The load is transferred from the fitting to the wood by two means: One is thebolts which pass through the fittings and the wood. The other is the metal strapacross the top of the spar. Ideally, this would be a single bent piece of metal,rather than three pieces welded, but to make this fitting in one piece isnot very feasible, thus it is designed as a welded fitting.I recall an earlier post of yours, indicating that you have capabilities in machining,but not in welding. Give in, Mike. You are either going to learn to weld,or find someone to do it for you. This old wooden airplane has lots of partsthat NEED to be welded.Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... __________

Original Posted By: "Bill Church"
This guy should be rich by now! :-)Clif send him one of these: http://www.flycorvair.com/6522223.jpg__ ... ___Subject: Pietenpol-List: Re: Resessed straps

Original Posted By: Michael Perez
>> Mike,>> If you really want to "repair" the pitch pocket you can always cut it out> and do a proper splice joint in your spar. Again, refer to AC 43.13-1B> Chapter 1 for details.>> But, in my opinion (as always, take it or leave it) you're talking about> spending maybe two hundred bucks more for a new piece of wood that's going> to be holding you (and maybe somebody you care about) up in the air. That's> most likely to be less than 2% of the cost of the complete airplane. And you> will still be able to use the "defective" board for other parts, so the net> cost to you is much less.>> Bill C.>>________________________________________________________________________________Date: Thu, 13 Nov 2008 08:24:33 -0800 (PST)