Original Posted By: "Jack Philips"
This email is primarily being sent to advise all Pietenpol builders of apotential problem. Hopefully I=92m the only one that this has or will happento, but I thought the Pietenpol community at large should be aware of it.Saturday, my wife and I flew from our home at Smith Mountain Lake, Virginiato Roxboro, NC to attend the annual Antique Fly-In of VAA Chapter 3, theCarolinas Virginia Antique Airplane Foundation. As I turned final forrunway 06, with a slight crosswind from the left (wind was 010=B0 at 5 knots),I noticed the rudder suddenly felt =93loose=94, although when I tried rudderinputs, it still worked. Karen commented on the intercom that she heard a=93clunk=94. I landed the airplane (made a good landing, for once), and then aswe slowed below rudder effectiveness speed, all Hell broke loose. A slightgust of wind hit from the left and the plane immediately turned left andheaded for the weeds. Tailwheel steering was completely gone. I got on thebrakes and got it straightened out, but it was the closest I=92ve come toground-looping in a long time. As we taxied to the flight line I lookedback over my shoulder and verified the rudder moved correctly with inputfrom my feet, although it felt funny. Tailwheel steering still didn=92t workat all, so I continued to steer with brakes and we got it to our place onthe flight line and shut it down.Once parked, I looked back at the rudder and the cables were slack ' notension at all. The rudder was banging back and forth in the breeze. Assoon as Karen got out of the front cockpit I removed the front seat to seewhat was going on. What I found was that the rudder bar pivot, the boltwith its head welded to the underside of the rudder bar mounting bracket,had broken completely off. The only thing holding the rudder bar atanything like the correct position was the single diagonal brace. No wonderthe rudder felt a bit strange!Assessing my options, I finally decided the only way to fix it and get backhome was to remove the bracket, drill out the welded bolt head and insert anew bolt. I built this system exactly according to the plans, except forthe use of 4130 chrome moly steel and I welded the bolt head to the bracketinstead of brazing it as the plans show (I had read that brazing 4130 wasnot recommended). The bolt broke right at the point where the shank met thehead and the crack was completely within the bracket so it was undetectable.I had just completed the annual condition inspection on the airplane twoweeks ago and as part of the inspection I had inspected and assured thesecurity of the rudder bar (as well as I could). This failure wascompletely hidden, and I don=92t know how it could have been detected, otherthan X-Ray inspection.To remove the bracket I had to cut a couple of holes in the fabric on thebelly of the airplane, because when I built it I was not smart enough toinstall nutplates for all the bolts that penetrate the floorboard. Evenworse, I had used castellated nuts with cotter pins, which made itespecially difficult to remove the nuts so I could repair the bracket. Once the bracket was free we examined the failure. Apparently the heat fromthe welding caused a small crack to form in the shank of the bolt adjacentto the head. Over the last 10 years and 317 hours of flying, the forces onthe rudder bar were sufficient to cause that crack to grow, to the pointthat it ruptured completely Saturday. The fractured bolt is shown below:Note the smooth almost polished appearance of the fracture.Here is an excerpt from the plans, showing the area in question:Of course, if you have to have a problem with your Pietenpol while away fromhome, it sure is nice to be at a fly-in like Brodhead or Oshkosh, or aVintage Airplane fly-in. People were very helpful, particularly Jimmy Deanand Jim Wilson, and a young man whom I only know as =93Dusty=94. As soon as Igot the bracket off, Dusty took it to his workshop and carefully drilled,then reamed a hole through the welded in bolt head and pressed a new 5/16=94AN5 bolt in it. Jimmy Dean and I reinstalled the bracket and mounted therudder bar. I patched the holes in the belly with Duct Tape and we wereback in business.So what can I learn from this and pass on to my friends in the Pietenpolcommunity? First, understand that there are some parts of these airplanesthat are very hard to inspect in a meaningful way. I had literallyinspected this part exactly two weeks before as part of the annual conditioninspection, and detected nothing wrong with a part that was obviously readyto fail catastrophically. I did inspect the security of the cotter pin inthe nut that secures the rudder bar to this bolt. I grabbed the rudder barand wiggled it to see if everything was tight, and the diagonal braceprevented any movement from alerting me to the failure. What more can bedone in an inspection? I don=92t know and am open to suggestions.What am I going to do with it now? I=92m going to make a new rudder barbracket, for one thing. I=92m not sure that brazing the bolt is the answer,so I think I=92m going to weld an extra thickness of 1/8=94 4130 in the middleof the bracket, then drill and ream an under sized hole and press fit thebolt in place. I=92m also going to add a second diagonal brace to withstandrudder bar forces better. Jimmy Dean said that the early Wacos had thistype of design and ended up adding a second brace to prevent failures. I=92malso going to install nutplates under the floorboard so it will be easier toremove and install the rudder bar bracket in the future. Then of courseI=92ve got to repair the holes I cut in the fabric.If you are building a Pietenpol and have not yet made these parts, study theplans carefully and determine how you want to do it. As I said, other thanusing 4130 for the bracket and welding the bolt head rather than brazing it,I made it exactly to the plans. I certainly would NOT weld the bolt head.If you can braze, then braze it. As far as I know there has not been afailure of a brazen bolt head, but then I haven=92t heard of any failures ofwelded ones until now. I do think two diagonal braces is better than oneand should provide much better bracing.Be careful up there,Jack PhillipsNX899JPSmith Mountain Lake, Virginia________________________________________________________________________________
Pietenpol-List: Caution - Rudder Bar Failure
RE: Pietenpol-List: Caution - Rudder Bar Failure
Original Posted By: owner-pietenpol-list-server(at)matronics.com
So glad it worked out OK, Jack. From my earlier flights with the old tailwheel, I know only too well the feeling of getting crossed up on the runway[yawn]. And, why do these things have to happen with an audience?! In yourcase it was just as well=85you got lots of good help. I had a forward rudderpedal break when I was allowing a friend to taxi from the front, and had tomake a forceful correction from the back. Close scrutiny at annual, and aquick look at pre-flight are in order. Good job with the brake work=85Gary BootheNX308MB
So glad it worked out OK, Jack. From my earlier flights with the old tailwheel, I know only too well the feeling of getting crossed up on the runway[yawn]. And, why do these things have to happen with an audience?! In yourcase it was just as well=85you got lots of good help. I had a forward rudderpedal break when I was allowing a friend to taxi from the front, and had tomake a forceful correction from the back. Close scrutiny at annual, and aquick look at pre-flight are in order. Good job with the brake work=85Gary BootheNX308MB
Re: Pietenpol-List: Caution - Rudder Bar Failure
Original Posted By: Jack Philips
Hi Jack,Thanks for your post, I'm doing an annual condition inspection and that's something to look out for.Your post and Dan Helspers' post about his prop are the things I really like about this list.Dick N. ----- Original Message -----
Hi Jack,Thanks for your post, I'm doing an annual condition inspection and that's something to look out for.Your post and Dan Helspers' post about his prop are the things I really like about this list.Dick N. ----- Original Message -----
Pietenpol-List: Re: Caution - Rudder Bar Failure
Original Posted By: "tstancy"
I packed up the project a few months ago in preparation to sell our house. We'llprobably buy land and build a new house.We found one set of plans that we like. Next to the two car garage is a enclosedworkshop/third garage. It measures 23'10" X 11' 10". With every foot I extendthis, I'm paying more for the slab (since it's part of the garage section) androof and walls (and heating).In a way, kind of dream to be able to design my play area. I may add two feetor so to make it 14' wide.I can always move my car out for smaller jobs as thetools are on rolling tables.What's your idea of the perfect construction area? Is there something you wishyou had? Where are you building now (or where did you build)? What if you coulddesign a room?--------JohnRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Caution - Rudder Bar Failure
I packed up the project a few months ago in preparation to sell our house. We'llprobably buy land and build a new house.We found one set of plans that we like. Next to the two car garage is a enclosedworkshop/third garage. It measures 23'10" X 11' 10". With every foot I extendthis, I'm paying more for the slab (since it's part of the garage section) androof and walls (and heating).In a way, kind of dream to be able to design my play area. I may add two feetor so to make it 14' wide.I can always move my car out for smaller jobs as thetools are on rolling tables.What's your idea of the perfect construction area? Is there something you wishyou had? Where are you building now (or where did you build)? What if you coulddesign a room?--------JohnRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Caution - Rudder Bar Failure
Original Posted By: "Douwe Blumberg"
In the spirit of gaining a greater understanding of why this type of failure occurred,I would like to present the following proposal:>From the Aircraft Spruce website for AN5 Bolts (5/16-24), on the Overview Tabit states, Hex head aircraft bolts are made of high-strength type 4037 or 8740alloy steel (type 8740 is the most commonly used).Ref: http://www.aircraftspruce.com/catalog/h ... 5.php>From the TW Metals website for 8740 Alloy Bar, the Minimum Tensile Yield Strengthis 152,000 psi.Ref: http://www.twmetals.com/8740-bar-rod-wire.htmlHowever, when an AN5 fastener is heated to 1500 degrees F (such as during the weldingprocess), the fastener becomes Annealed in the Heat Affected Zone and thenonly possesses a Tensile Yield Strength of 60,200 psi.Ref: http://asm.matweb.com/search/SpecificMa ... ultiplying the annealed Tensile Yield Strength value of 60,200 psi by the AN5bolts cross-section area (.07499 square inches at the bolts minimum design diameterof .309), we find the Annealed AN5 Bolt can handle 4,514 pounds of TensileForce before it begins to yield (permanently deform).Example: 60,200 (pounds/square inch) x .07499 (square inches) = 4,514 (pounds)Assumption: A human cannot apply 4,500 pounds of load to the Rudder Pivot Point,even with both feet and a lever arm of approximately 1 inch.Therefore, the following Static Strength Conclusion can be made: An Annealed AN5Bolt is more than strong enough to handle the Rudder Bar Pedal loads.So, what happened?A Stainless Steel Bolt when heated to a high temperature (i.e. welding) will absorbHydrogen molecules, if Hydrogen is present in the atmosphere during the elevatedtemperature period. These Hydrogen molecules combine with the Carbon thatis alloyed to the Iron to form Methane Gas. The Methane Gas collects in smallvoids along the grain boundaries where it builds up enormous pressures thatwill eventually initiate cracks. These cracks will initiate quicker and propagateunder load. This is called Hydrogen Embrittlement cracking.Ref: http://www.corrosionist.com/hydrogen_em ... s.htmThese micro-cracks would propagate during the cycling action of applying the Rudder.Therefore, Hydrogen Embrittlement fatigue cracking is the most likely causeof this Rudder Bar Bolt failure.To avoid absorbing Hydrogen molecules, you must remove all exposure to Hydrogenduring the welding process and continue to maintain a Hydrogen-free atmosphereduring the cooling process (i.e. continual inert gas flow).An alternative to Welding is Brazing (per the plan).Brazing occurs around 800 degrees F and provides sufficient mechanical strengthnecessary to create a Rudder Bar Pivot Point, even though the AN5 Bolt is annealedduring the Brazing process. At this reduced temperature, Hydrogen moleculesare not absorbed into the grain boundary of the Stainless Steel.Respectfully,Tom StancyRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
In the spirit of gaining a greater understanding of why this type of failure occurred,I would like to present the following proposal:>From the Aircraft Spruce website for AN5 Bolts (5/16-24), on the Overview Tabit states, Hex head aircraft bolts are made of high-strength type 4037 or 8740alloy steel (type 8740 is the most commonly used).Ref: http://www.aircraftspruce.com/catalog/h ... 5.php>From the TW Metals website for 8740 Alloy Bar, the Minimum Tensile Yield Strengthis 152,000 psi.Ref: http://www.twmetals.com/8740-bar-rod-wire.htmlHowever, when an AN5 fastener is heated to 1500 degrees F (such as during the weldingprocess), the fastener becomes Annealed in the Heat Affected Zone and thenonly possesses a Tensile Yield Strength of 60,200 psi.Ref: http://asm.matweb.com/search/SpecificMa ... ultiplying the annealed Tensile Yield Strength value of 60,200 psi by the AN5bolts cross-section area (.07499 square inches at the bolts minimum design diameterof .309), we find the Annealed AN5 Bolt can handle 4,514 pounds of TensileForce before it begins to yield (permanently deform).Example: 60,200 (pounds/square inch) x .07499 (square inches) = 4,514 (pounds)Assumption: A human cannot apply 4,500 pounds of load to the Rudder Pivot Point,even with both feet and a lever arm of approximately 1 inch.Therefore, the following Static Strength Conclusion can be made: An Annealed AN5Bolt is more than strong enough to handle the Rudder Bar Pedal loads.So, what happened?A Stainless Steel Bolt when heated to a high temperature (i.e. welding) will absorbHydrogen molecules, if Hydrogen is present in the atmosphere during the elevatedtemperature period. These Hydrogen molecules combine with the Carbon thatis alloyed to the Iron to form Methane Gas. The Methane Gas collects in smallvoids along the grain boundaries where it builds up enormous pressures thatwill eventually initiate cracks. These cracks will initiate quicker and propagateunder load. This is called Hydrogen Embrittlement cracking.Ref: http://www.corrosionist.com/hydrogen_em ... s.htmThese micro-cracks would propagate during the cycling action of applying the Rudder.Therefore, Hydrogen Embrittlement fatigue cracking is the most likely causeof this Rudder Bar Bolt failure.To avoid absorbing Hydrogen molecules, you must remove all exposure to Hydrogenduring the welding process and continue to maintain a Hydrogen-free atmosphereduring the cooling process (i.e. continual inert gas flow).An alternative to Welding is Brazing (per the plan).Brazing occurs around 800 degrees F and provides sufficient mechanical strengthnecessary to create a Rudder Bar Pivot Point, even though the AN5 Bolt is annealedduring the Brazing process. At this reduced temperature, Hydrogen moleculesare not absorbed into the grain boundary of the Stainless Steel.Respectfully,Tom StancyRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Re: Pietenpol-List: NEED ADVICE!!!!
Original Posted By: Ken Bickers
Hey guys,I just found out about a potential disaster..Turns out I have to do a presentation in Denver the Friday morning ofBrodhead. THIS CANT BE REAL!!!!!!!So, I'm trying to figure out where is the closest to Brodhead I could catcha flight Thursday night or super early Friday for Denver, do thepresentation Friday morning and fly back so I could be there for Sat morningdawn patrol. Marci will be there with our car to drive me and pick me up.Do any of you commercial dudes know which airports are around there? IsMadison decently large??Douwe________________________________________________________________________________Date: Wed, 27 May 2015 18:08:26 -0600Subject: Re: Pietenpol-List: NEED ADVICE!!!!
Hey guys,I just found out about a potential disaster..Turns out I have to do a presentation in Denver the Friday morning ofBrodhead. THIS CANT BE REAL!!!!!!!So, I'm trying to figure out where is the closest to Brodhead I could catcha flight Thursday night or super early Friday for Denver, do thepresentation Friday morning and fly back so I could be there for Sat morningdawn patrol. Marci will be there with our car to drive me and pick me up.Do any of you commercial dudes know which airports are around there? IsMadison decently large??Douwe________________________________________________________________________________Date: Wed, 27 May 2015 18:08:26 -0600Subject: Re: Pietenpol-List: NEED ADVICE!!!!
Pietenpol-List: Re: NEED ADVICE!!!!
Original Posted By: "curtdm(at)gmail.com"
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________________________________________________________________________________Subject: Pietenpol-List: Re: NEED ADVICE!!!!
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________________________________________________________________________________Subject: Pietenpol-List: Re: NEED ADVICE!!!!
Original Posted By: "Jack Philips"
Douwe,Southwest has non-stops from MKE to DENThursday 7:40pm lands 9:10Friday 5:35am lands 7:05ReturnFriday 4:00pm lands 7:10Friday 8:45pm lands 11:55--------Curt MerdanFlower Mound, TXRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Douwe,Southwest has non-stops from MKE to DENThursday 7:40pm lands 9:10Friday 5:35am lands 7:05ReturnFriday 4:00pm lands 7:10Friday 8:45pm lands 11:55--------Curt MerdanFlower Mound, TXRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
RE: Pietenpol-List: Re: Caution - Rudder Bar Failure
Original Posted By: owner-pietenpol-list-server(at)matronics.com [mailto:owner-pietenpol-list-server(at)matronics.com] On Behalf Of tstancy
Tom,I definitely think the bolt developed a crack from the welding process. I don'tknow if hydrogen embrittlement was the culprit (it's not stainless steel, butother forms of steel can be susceptible to hydrogen embrittlement as well).Your analysis is correct, and an annealed bolt should be more than strong enough,which is why I felt welding it was safe.I think the tension applied to the rudder bar by the tailwheel steering springs,counteracted by forces from the pilot's (my) feet, set up a slight oscillatingdisplacement which allowed the crack to propagate to the point of ultimatefailure.Brazing would be best, but I had read several articles that claim you should notbraze 4130 chromoly steel. Since 4130 is what I had, and I didn't have anybrazing rod, I decided to weld it. I'm not alone, nearly every Pietenpol builderI've talked to about this also welded theirs. The unsettling thing aboutthis failure is the inherent lack of inspectability.I do think adding a second diagonal brace going to the left side will vastly improvethe strength of the whole assembly. It has always bothered me how muchup and down play there can be at the ends of a Pietenpol rudder bar. Some ofthat is due to the fact that the assembly is not well constrained.So I agree with your conclusion, and recommend that all builders who are in theprocess should "build it to the plans" (have we heard that somewhere before?).Braze, rather than weld that bolt. And while you are at it, add the left handdiagonal brace, such as WACO airplanes did on their rudder bars.Jack PhillipsNX899JPSmith Mountain Lake, Virginia-----Original Message-----
Tom,I definitely think the bolt developed a crack from the welding process. I don'tknow if hydrogen embrittlement was the culprit (it's not stainless steel, butother forms of steel can be susceptible to hydrogen embrittlement as well).Your analysis is correct, and an annealed bolt should be more than strong enough,which is why I felt welding it was safe.I think the tension applied to the rudder bar by the tailwheel steering springs,counteracted by forces from the pilot's (my) feet, set up a slight oscillatingdisplacement which allowed the crack to propagate to the point of ultimatefailure.Brazing would be best, but I had read several articles that claim you should notbraze 4130 chromoly steel. Since 4130 is what I had, and I didn't have anybrazing rod, I decided to weld it. I'm not alone, nearly every Pietenpol builderI've talked to about this also welded theirs. The unsettling thing aboutthis failure is the inherent lack of inspectability.I do think adding a second diagonal brace going to the left side will vastly improvethe strength of the whole assembly. It has always bothered me how muchup and down play there can be at the ends of a Pietenpol rudder bar. Some ofthat is due to the fact that the assembly is not well constrained.So I agree with your conclusion, and recommend that all builders who are in theprocess should "build it to the plans" (have we heard that somewhere before?).Braze, rather than weld that bolt. And while you are at it, add the left handdiagonal brace, such as WACO airplanes did on their rudder bars.Jack PhillipsNX899JPSmith Mountain Lake, Virginia-----Original Message-----
Pietenpol-List: Re: Caution - Rudder Bar Failure
Original Posted By: goffelectric(at)comcast.net
Re: Pietenpol-List: NEED ADVICE!!!!
Original Posted By: Michael Perez
Dang it Douwe you will miss our Brat lunch! Sent from my iPadJack Textor> On May 27, 2015, at 7:04 PM, "Douwe Blumberg" wrote:> > Hey guys,> > I just found out about a potential disaster.> > Turns out I have to do a presentation in Denver the Friday morning of Brodhead. THIS CANT BE REAL!!!!!!!> > So, I=99m trying to figure out where is the closest to Brodhead I could catch a flight Thursday night or super early Friday for Denver, do the presentation Friday morning and fly back so I could be there for Sat morning dawn patrol. Marci will be there with our car to drive me and pick me up.> > Do any of you commercial dudes know which airports are around there? Is Madison decently large??> > Douwe> > 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D> ________________________________________________________________________________Date: Thu, 28 May 2015 12:12:20 +0000 (UTC)
Dang it Douwe you will miss our Brat lunch! Sent from my iPadJack Textor> On May 27, 2015, at 7:04 PM, "Douwe Blumberg" wrote:> > Hey guys,> > I just found out about a potential disaster.> > Turns out I have to do a presentation in Denver the Friday morning of Brodhead. THIS CANT BE REAL!!!!!!!> > So, I=99m trying to figure out where is the closest to Brodhead I could catch a flight Thursday night or super early Friday for Denver, do the presentation Friday morning and fly back so I could be there for Sat morning dawn patrol. Marci will be there with our car to drive me and pick me up.> > Do any of you commercial dudes know which airports are around there? Is Madison decently large??> > Douwe> > 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D> ________________________________________________________________________________Date: Thu, 28 May 2015 12:12:20 +0000 (UTC)
RE: Pietenpol-List: Re: Caution - Rudder Bar Failure
Original Posted By: owner-pietenpol-list-server(at)matronics.com [mailto:owner-pietenpol-list-server(at)matronics.com] On Behalf Of goffelectric(at)comcast.net
Keith,Based on my recent experience, I would say no. In actuality, it would probablybe fine, but since the area in question on the bolt can't be inspected (unlessyou have access to an X-Ray Inspection facility), you would never know if asmall crack developed from your tack welding. It just depends on how much riskyou are willing to live with in the control system of your airplane.Jack PhillipsNX899JPSmith Mountain Lake, Virginia-----Original Message-----
Keith,Based on my recent experience, I would say no. In actuality, it would probablybe fine, but since the area in question on the bolt can't be inspected (unlessyou have access to an X-Ray Inspection facility), you would never know if asmall crack developed from your tack welding. It just depends on how much riskyou are willing to live with in the control system of your airplane.Jack PhillipsNX899JPSmith Mountain Lake, Virginia-----Original Message-----
Pietenpol-List: Re: Caution - Rudder Bar Failure
Original Posted By: goffelectric(at)comcast.net