Original Posted By: "Ed Grentzer"
As I have been going over and over it I have a strong suspiscion of what mayhave happened to Joe and his Celebrity.My dad had just talked to Joe a couple weeks before the accident. Joe hadcalled and asked my dad what his opinion was on fabric not being stitched tothe ribs. My dad told him there are alot of builders who just glue thefabric to the ribs, but it's a very smart idea to have them stitched.Especially since the ribs on joe's plane were 1/4 x 1/4 " capstrips. Not alot of glue surface for the fabric.The reason Joe was asking was because he had noticed an area(s) ofdelamination on one of the wings. My dad told him to ground the airplaneand fix the problem by re-covering/stitching.About a week later Joe called my dad again and said he had washed the planeand noticed that the fabric was tight again. My dad informed him that thatstill didn't sound good. Especially considering the fabric was at least10yrs old and the past 6 months the airplane had been sitting out in the AZsun on the ramp. The last few weeks have been 100+ weather.From what witnesses say the plane began to come apart in the air secondsbefore one of the wings folded. The parts that came from the plane prior towing failure were wood pieces. Joe's plane was the steel tube version of thefuse and had a wood wing.I'm thinkning that the fabric may have came loose in certain areas and gotsucked off. As it failed it probably pulled some of the internal wingstructure with it as well as the rest of the fabric, hence the wood piecescoming from the plane. At that point the drag was probably too great andthe wing folded back, or possibly once the fabric had been ripped from thewing, the plane went into a severe attitude which over stressed the wings.In any case I really think lack of stitching the fabric and it's hazardousdelaminating condidtion may have played a role.It seems to fit the scenario, but only time and the NTSB will really be ableto solve it.Have any of you heard of other accidents involving fabric comeing loose dueto lack of stitching?DJ VeghMesa, AZGN-1/Piet hybridwww.raptoronline.com N74DV________________________________________________________________________________
Pietenpol-List: my initial thoughts as to cause
RE: Pietenpol-List: my initial thoughts as to cause
Original Posted By: Kent Hallsten
This is an interesting point. Even if the fabric doesn't delaminate, beingglued to the ribs rather than stitched changes the rib loading fromcompression (with stitching) to tension, at least in the low-pressure partof the airfoil. We haven't heard much about rib loading in the "glue vs.stitch" debate.Gene________________________________________________________________________________
This is an interesting point. Even if the fabric doesn't delaminate, beingglued to the ribs rather than stitched changes the rib loading fromcompression (with stitching) to tension, at least in the low-pressure partof the airfoil. We haven't heard much about rib loading in the "glue vs.stitch" debate.Gene________________________________________________________________________________
RE: Pietenpol-List: my initial thoughts as to cause
Original Posted By: "Steve Eldredge"
DJ,I'm saddened to hear of your friend and his daughter, it's not easy thinkingabout it. As you keep going forward with your plane and focus on safebuilding practices, the time will help you feel better. Unfortunately toomany of us know this feeling. My friend, a pilot, went down with a family offour, two brothers and their sons. (It was not a homebuilt, by the way). Hewas about to start instructing me, too. It blew me away. I still wonderabout how he let it happen, 21 years later, but I hope I learned from it. If you can find out any more from this accident, please keep us informed. Iwould like to know what glue was used to assemble the ribs and wings, forexample. You mention how hot it was, and the plane sat outside for awhile.Right now you and your Dad know that Joe had questions about the covering,and asked for advice. Joe asked for help and it sounds like he got goodadvice from your Dad. We can't tell if he followed it, and you can't keepthinking "if only I did this, or that". You can eat yourself up thinkingabout how it happened or what you could have done. Let's hope Joe had hisplane inspected and looked at by other builders and knowledgeable people,and didn't blindly trust that just because it was a Fisher built plane itwas ok. You may try to ease your mind by thinking this happened fromsomething totally unforeseen, even at any inspection. A flaw deep in thespar, a micro crack in a bolt, something, anything, but the obvious. But Ican go along with your reasoning about the cause for now. You asked for other failures and one covering failure I remember was SteveWittman's O&O Special, a modified Tailwind design. Steve had fabric coveredplywood skinned wings. No rib stitching used here, but the adhesive he usedto attach the fabric was the wrong type , and the covering peeled off athigh speed, resulting in a crash taking Steve and his wife. Steve wasdesigning and building race planes from the 1930's, but with all hisknowledge this was something that got past him, and I think no matter howcareful you are, you just can't think of everything and check everything allthe time. Of course there was speculation about the cause, and guesses ofhow the accident happened. Many of them had nothing to do with the realreason for the accident and were way off base. When the report came out andtold what happened, it seemed so simple. But how could someone of Steve'scaliber and experience, who was way ahead of his time, have made a mistakeon something like that? As homebuilders we have access to many resources and information that didn'texist 10 or 15 years ago. It should be so easy not to make mistakes in thisday and age, but they still happen and they always will. Maybe we have anoverabundance of information and opinions, I don't know. I know that Iwouldn't be building if the internet hadn't happened. Really! I never knewthat regular guys like you and me could just build our own airplane! But wehave so much at our fingertips now it blows my mind. Just think for a minutehow much harder it would be to do what we do today if we couldn't writeinstantly to our buddies on the list and ask questions? And I'm notforgetting to use the local gurus either. You know, I met Leonard last nightat our chapter picnic. A guy who has been around about 70 years. He talkedabout stuff I can't even understand right now, from gasoline to airfoils,and it's sad to think about all his knowledge that won't get used by theyounger guys, and he lives right in town! I'm glad to be in his chapter,something should rub off on me.
Here on this list we have people all across the country ready to help,everyone is so eager to help. All we have to do is holler. But in the end Ibelieve nothing beats an extra pair of eyes. Get as many people involved inyour plane as possible. Let all the advice sink in, and take your time!Jeez DJ, your building pace is impressive. You must trust what you havedone completely, so keep going forward. It looks great from the web site,too. Everyone is different, our skills are different, our attitudes, etc.Don't take offense DJ, but it would be scary for me to build as quick as youhave. And I don't think you are doing anything wrong! I met another guy lastnight who built an RV-8 in a year! But my abilities and life experiencesare different. It has taken me about 5-6 months to build 18 ribs! And theyare not perfect, but somehow I trust them! But I haven't shown them toanyone in my chapter yet. Why not? I guess I don't want some body to saythey are not good enough. But I think, I'm only talking about a few dollarsworth of wood and glue! They are so easy to build! What can go wrong, Ithink? These things are cake! And only 41 hours of building. You see mypride showing, don't you? It could bite me later. But I won't let thathappen, I will show my chapter buddies and get re-assurance that everythingis good, and go from there. I'm glad you have your Dad to help, and he has you to help him. This tragedymay have a good effect in the building and completion of your GN-1 and yourDad's plane. It won't lessen the pain right away, but it will ease in timeas you both work together to build the safest aircraft you can. Keep up thegood work DJ. Kent________________________________________________________________________________Subject: RE: Pietenpol-List: my initial thoughts as to causeDate: Wed, 12 Jun 2002 09:02:56 -0600
DJ,I'm saddened to hear of your friend and his daughter, it's not easy thinkingabout it. As you keep going forward with your plane and focus on safebuilding practices, the time will help you feel better. Unfortunately toomany of us know this feeling. My friend, a pilot, went down with a family offour, two brothers and their sons. (It was not a homebuilt, by the way). Hewas about to start instructing me, too. It blew me away. I still wonderabout how he let it happen, 21 years later, but I hope I learned from it. If you can find out any more from this accident, please keep us informed. Iwould like to know what glue was used to assemble the ribs and wings, forexample. You mention how hot it was, and the plane sat outside for awhile.Right now you and your Dad know that Joe had questions about the covering,and asked for advice. Joe asked for help and it sounds like he got goodadvice from your Dad. We can't tell if he followed it, and you can't keepthinking "if only I did this, or that". You can eat yourself up thinkingabout how it happened or what you could have done. Let's hope Joe had hisplane inspected and looked at by other builders and knowledgeable people,and didn't blindly trust that just because it was a Fisher built plane itwas ok. You may try to ease your mind by thinking this happened fromsomething totally unforeseen, even at any inspection. A flaw deep in thespar, a micro crack in a bolt, something, anything, but the obvious. But Ican go along with your reasoning about the cause for now. You asked for other failures and one covering failure I remember was SteveWittman's O&O Special, a modified Tailwind design. Steve had fabric coveredplywood skinned wings. No rib stitching used here, but the adhesive he usedto attach the fabric was the wrong type , and the covering peeled off athigh speed, resulting in a crash taking Steve and his wife. Steve wasdesigning and building race planes from the 1930's, but with all hisknowledge this was something that got past him, and I think no matter howcareful you are, you just can't think of everything and check everything allthe time. Of course there was speculation about the cause, and guesses ofhow the accident happened. Many of them had nothing to do with the realreason for the accident and were way off base. When the report came out andtold what happened, it seemed so simple. But how could someone of Steve'scaliber and experience, who was way ahead of his time, have made a mistakeon something like that? As homebuilders we have access to many resources and information that didn'texist 10 or 15 years ago. It should be so easy not to make mistakes in thisday and age, but they still happen and they always will. Maybe we have anoverabundance of information and opinions, I don't know. I know that Iwouldn't be building if the internet hadn't happened. Really! I never knewthat regular guys like you and me could just build our own airplane! But wehave so much at our fingertips now it blows my mind. Just think for a minutehow much harder it would be to do what we do today if we couldn't writeinstantly to our buddies on the list and ask questions? And I'm notforgetting to use the local gurus either. You know, I met Leonard last nightat our chapter picnic. A guy who has been around about 70 years. He talkedabout stuff I can't even understand right now, from gasoline to airfoils,and it's sad to think about all his knowledge that won't get used by theyounger guys, and he lives right in town! I'm glad to be in his chapter,something should rub off on me.
Here on this list we have people all across the country ready to help,everyone is so eager to help. All we have to do is holler. But in the end Ibelieve nothing beats an extra pair of eyes. Get as many people involved inyour plane as possible. Let all the advice sink in, and take your time!Jeez DJ, your building pace is impressive. You must trust what you havedone completely, so keep going forward. It looks great from the web site,too. Everyone is different, our skills are different, our attitudes, etc.Don't take offense DJ, but it would be scary for me to build as quick as youhave. And I don't think you are doing anything wrong! I met another guy lastnight who built an RV-8 in a year! But my abilities and life experiencesare different. It has taken me about 5-6 months to build 18 ribs! And theyare not perfect, but somehow I trust them! But I haven't shown them toanyone in my chapter yet. Why not? I guess I don't want some body to saythey are not good enough. But I think, I'm only talking about a few dollarsworth of wood and glue! They are so easy to build! What can go wrong, Ithink? These things are cake! And only 41 hours of building. You see mypride showing, don't you? It could bite me later. But I won't let thathappen, I will show my chapter buddies and get re-assurance that everythingis good, and go from there. I'm glad you have your Dad to help, and he has you to help him. This tragedymay have a good effect in the building and completion of your GN-1 and yourDad's plane. It won't lessen the pain right away, but it will ease in timeas you both work together to build the safest aircraft you can. Keep up thegood work DJ. Kent________________________________________________________________________________Subject: RE: Pietenpol-List: my initial thoughts as to causeDate: Wed, 12 Jun 2002 09:02:56 -0600RE: Pietenpol-List: my initial thoughts as to cause
Original Posted By: owner-pietenpol-list-server(at)matronics.com
I believe this is what happened in Steve Whitman's crash. He was thedesigner of the Whitman Tailwind. Prelim reports point to fabric flutter onthe wings causing a wing failure, due to the fabric not being stitched, onlyglued.Mark Tracymtracy@prosoft-technology.comProsoft Technology, Inc.1675 Chester AveFourth FloorBakersfield, CA 93301Ph: 661-716-5110Fax: 661-716-5101-----Original Message-----
I believe this is what happened in Steve Whitman's crash. He was thedesigner of the Whitman Tailwind. Prelim reports point to fabric flutter onthe wings causing a wing failure, due to the fabric not being stitched, onlyglued.Mark Tracymtracy@prosoft-technology.comProsoft Technology, Inc.1675 Chester AveFourth FloorBakersfield, CA 93301Ph: 661-716-5110Fax: 661-716-5101-----Original Message-----
RE: Pietenpol-List: my initial thoughts as to cause
Original Posted By: owner-pietenpol-list-server(at)matronics.com
wow Kent.... an excellent reply. you are right about me being 110% sureon my GN-1. From this point forward I'm going to triple check evry inch andthen triple check it again.Thats the one benefit myself and my dad have over Joe. We are building ourown and will know every micro detail. Joe put alot of trust in his planeand it's builder. And to be honest when he first got it so id my dad and I.My dad flew it several times. My dad decided he was not going to fly itanymore until Joe stitched the ribs. I'm glad Joe called my dad to tell himabout that... otherwise my dad may have flown it.On a lighter note.... I figured I should not temporarily stop working on myplane. It's a stress releiver for me and this case is no different. Iinstalled the freshly silver powder coated control stick and rudder pedalsover the past couple nights. she's lookin good. pics are on my site.DJ VeghMesa, AZGN-1/Piet hybridwww.raptoronline.com N74DV-----Original Message-----
wow Kent.... an excellent reply. you are right about me being 110% sureon my GN-1. From this point forward I'm going to triple check evry inch andthen triple check it again.Thats the one benefit myself and my dad have over Joe. We are building ourown and will know every micro detail. Joe put alot of trust in his planeand it's builder. And to be honest when he first got it so id my dad and I.My dad flew it several times. My dad decided he was not going to fly itanymore until Joe stitched the ribs. I'm glad Joe called my dad to tell himabout that... otherwise my dad may have flown it.On a lighter note.... I figured I should not temporarily stop working on myplane. It's a stress releiver for me and this case is no different. Iinstalled the freshly silver powder coated control stick and rudder pedalsover the past couple nights. she's lookin good. pics are on my site.DJ VeghMesa, AZGN-1/Piet hybridwww.raptoronline.com N74DV-----Original Message-----
Re: Pietenpol-List: my initial thoughts as to cause
Original Posted By: "Mark Tracy"
A Tailwind wing is covered with ply wood. The fabric is glued on. Nostitching possible. Steve used nitrate dope to glue the fabric over theplywood which is fine for cotton but doesn't have much strength withpolyester fabric. He saved some money when he should have used somepoly-tac or super-seam cement. It didn't fail for about 10 years.----- Original Message -----
A Tailwind wing is covered with ply wood. The fabric is glued on. Nostitching possible. Steve used nitrate dope to glue the fabric over theplywood which is fine for cotton but doesn't have much strength withpolyester fabric. He saved some money when he should have used somepoly-tac or super-seam cement. It didn't fail for about 10 years.----- Original Message -----