Original Posted By: Michael Perez
Pietenpol-List: Bend in push pull tube
Re: Pietenpol-List: Tail braces in place of cables
Original Posted By: Michael Perez
hello Mike P., a local vender that does swaging of cables does them for under $10 per end on the cables. At this sum it is not cost effective to buy turnbuckles. Even when you toss in the price of the the threaded end and fork which by the way can be right and left hand thread they are much cheaper than buying four turnbuckles. They also look very nice. I have over the years cussed my rods out because of the constant corrosion issues.Ernie Moreno ----- Original Message -----
hello Mike P., a local vender that does swaging of cables does them for under $10 per end on the cables. At this sum it is not cost effective to buy turnbuckles. Even when you toss in the price of the the threaded end and fork which by the way can be right and left hand thread they are much cheaper than buying four turnbuckles. They also look very nice. I have over the years cussed my rods out because of the constant corrosion issues.Ernie Moreno ----- Original Message -----
Re: Pietenpol-List: Bend in push pull tube
Original Posted By: Michael Perez
A bend will drastically reduce the compression strength of the push rod. The bend adds moment arm and then you have something called "beam-column bending" which tends to greatly reduce the compression strength of a simple column.For a particular case, you'd need to do some analysis. One of the better references is by Bruhn, and a good technical library will have a copy. Otherwise the ASM that I'd previously recommended will do fine, but it's a bit more difficult to use.But you can always make one like that and give it a try on the ground. If you can put your maximum strength on the stick without bending or collapsing the tube, it's probably okay. Hint - don't try that on the real airplane. Try it on a mockpit with test hardware, not flight hardware.David Paule ----- Original Message -----
A bend will drastically reduce the compression strength of the push rod. The bend adds moment arm and then you have something called "beam-column bending" which tends to greatly reduce the compression strength of a simple column.For a particular case, you'd need to do some analysis. One of the better references is by Bruhn, and a good technical library will have a copy. Otherwise the ASM that I'd previously recommended will do fine, but it's a bit more difficult to use.But you can always make one like that and give it a try on the ground. If you can put your maximum strength on the stick without bending or collapsing the tube, it's probably okay. Hint - don't try that on the real airplane. Try it on a mockpit with test hardware, not flight hardware.David Paule ----- Original Message -----
Re: Pietenpol-List: Tail braces in place of cables
Original Posted By: Michael Perez
Re: Pietenpol-List: Bend in push pull tube
Original Posted By: Michael Perez
RE: Pietenpol-List: Bend in push pull tube
Original Posted By: owner-pietenpol-list-server(at)matronics.com [mailto:owner-pietenpol-lis
Michael,=C2-Here are some pics of my idler arm. My seat bottom is framed per plans. The push/pull rod travels up and down at the idler arm, approximately =C2=BE=9D.=C2-Just a thoughtif you ran two stringers along the bottom of your fuse, beyond the seat bottom, you could easily pick up another 1=9D of clearance.=C2-Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done,=C2-Fuselage=C2-on gear(16 ribs down)
Michael,=C2-Here are some pics of my idler arm. My seat bottom is framed per plans. The push/pull rod travels up and down at the idler arm, approximately =C2=BE=9D.=C2-Just a thoughtif you ran two stringers along the bottom of your fuse, beyond the seat bottom, you could easily pick up another 1=9D of clearance.=C2-Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done,=C2-Fuselage=C2-on gear(16 ribs down)
Re: Pietenpol-List: Bend in push pull tube
Original Posted By: Michael Perez
Another thing to consider is the effect of repeated bending on that push rod at the bend. =C2-Eventually that rod will weaken from fatigue. =C2-I don't know enough to tell you how to calculate when it would fail from fatigue, but eventually it probably would. =C2-It might be after 100hrs or 100,000hrs, I have no idea. =C2-It will depend on the bend angle, stick forces, etc.One elegant way to deal with this broblem is to put a bearing where you need the bend and attach two pushrods to it, one on each side, so you have translational motion on the first pushrod, purely rotational motion around the bearing, and then purely translational motion in a new direction via the second pushrod. =C2-I don't know what that is called, but you see it a lot on old warbirds, and you can change the direction of the pushrod to any angle you want with no concerns about durability.Steve RuseNorman, OK-- Sent from my Palm Pr=C4=93David Paule wrote:A bend will drastically reduce the compression strength of the push rod. =C2-The bend adds moment arm and then you have something called "beam-column bending" which tends to greatly reduce the compression strength of a simple column.=C2-For a particular case, you'd need to do some analysis. One of the better references is by Bruhn, and a good technical library will have a copy. Otherwise the ASM that I'd previously recommended will do fine, but it's a bit more difficult to use.=C2-But you can always make one like that and give it a try on the ground. If you can put your maximum strength on the stick without bending or collapsing the tube, it's probably okay. Hint - don't try that on the real airplane. Try it on a mockpit with test hardware, not flight hardware.=C2-David Paule=C2------ Original Message -----
Another thing to consider is the effect of repeated bending on that push rod at the bend. =C2-Eventually that rod will weaken from fatigue. =C2-I don't know enough to tell you how to calculate when it would fail from fatigue, but eventually it probably would. =C2-It might be after 100hrs or 100,000hrs, I have no idea. =C2-It will depend on the bend angle, stick forces, etc.One elegant way to deal with this broblem is to put a bearing where you need the bend and attach two pushrods to it, one on each side, so you have translational motion on the first pushrod, purely rotational motion around the bearing, and then purely translational motion in a new direction via the second pushrod. =C2-I don't know what that is called, but you see it a lot on old warbirds, and you can change the direction of the pushrod to any angle you want with no concerns about durability.Steve RuseNorman, OK-- Sent from my Palm Pr=C4=93David Paule wrote:A bend will drastically reduce the compression strength of the push rod. =C2-The bend adds moment arm and then you have something called "beam-column bending" which tends to greatly reduce the compression strength of a simple column.=C2-For a particular case, you'd need to do some analysis. One of the better references is by Bruhn, and a good technical library will have a copy. Otherwise the ASM that I'd previously recommended will do fine, but it's a bit more difficult to use.=C2-But you can always make one like that and give it a try on the ground. If you can put your maximum strength on the stick without bending or collapsing the tube, it's probably okay. Hint - don't try that on the real airplane. Try it on a mockpit with test hardware, not flight hardware.=C2-David Paule=C2------ Original Message -----
Re: Pietenpol-List: Bend in push pull tube
Original Posted By: Michael Perez
Another thing to consider is the effect of repeated bending on that push rodat the bend. Eventually that rod will weaken from fatigue. I don't knowenough to tell you how to calculate when it would fail from fatigue, buteventually it probably would. It might be after 100hrs or 100,000hrs, Ihave no idea. It will depend on the bend angle, stick forces, etc.One elegant way to deal with this broblem is to put a bearing where you needthe bend and attach two pushrods to it, one on each side, so you havetranslational motion on the first pushrod, purely rotational motion aroundthe bearing, and then purely translational motion in a new direction via thesecond pushrod. I don't know what that is called, but you see it a lot onold warbirds, and you can change the direction of the pushrod to any angleyou want with no concerns about durability.Steve RuseNorman, OK-- Sent from my Palm Pr=E7 _____ David Paule wrote:A bend will drastically reduce the compression strength of the push rod. The bend adds moment arm and then you have something called "beam-columnbending" which tends to greatly reduce the compression strength of a simplecolumn.For a particular case, you'd need to do some analysis. One of the betterreferences is by Bruhn, and a good technical library will have a copy.Otherwise the ASM that I'd previously recommended will do fine, but it's abit more difficult to use.But you can always make one like that and give it a try on the ground. Ifyou can put your maximum strength on the stick without bending or collapsingthe tube, it's probably okay. Hint - don't try that on the real airplane.Try it on a mockpit with test hardware, not flight hardware.David Paule----- Original Message -----
Another thing to consider is the effect of repeated bending on that push rodat the bend. Eventually that rod will weaken from fatigue. I don't knowenough to tell you how to calculate when it would fail from fatigue, buteventually it probably would. It might be after 100hrs or 100,000hrs, Ihave no idea. It will depend on the bend angle, stick forces, etc.One elegant way to deal with this broblem is to put a bearing where you needthe bend and attach two pushrods to it, one on each side, so you havetranslational motion on the first pushrod, purely rotational motion aroundthe bearing, and then purely translational motion in a new direction via thesecond pushrod. I don't know what that is called, but you see it a lot onold warbirds, and you can change the direction of the pushrod to any angleyou want with no concerns about durability.Steve RuseNorman, OK-- Sent from my Palm Pr=E7 _____ David Paule wrote:A bend will drastically reduce the compression strength of the push rod. The bend adds moment arm and then you have something called "beam-columnbending" which tends to greatly reduce the compression strength of a simplecolumn.For a particular case, you'd need to do some analysis. One of the betterreferences is by Bruhn, and a good technical library will have a copy.Otherwise the ASM that I'd previously recommended will do fine, but it's abit more difficult to use.But you can always make one like that and give it a try on the ground. Ifyou can put your maximum strength on the stick without bending or collapsingthe tube, it's probably okay. Hint - don't try that on the real airplane.Try it on a mockpit with test hardware, not flight hardware.David Paule----- Original Message -----
Re: Pietenpol-List: Bend in push pull tube
Original Posted By: Michael Perez
Another thing to consider is the effect of repeated bending on that push rod at the bend. =C2-Eventually that rod will weaken from fatigue. =C2-I don't know enough to tell you how to calculate when it would fail from fatigue, but eventually it probably would. =C2-It might be after 100hrs or 100,000hrs, I have no idea. =C2-It will depend on the bend angle, stick forces, etc.One elegant way to deal with this broblem is to put a bearing where you need the bend and attach two pushrods to it, one on each side, so you have translational motion on the first pushrod, purely rotational motion around the bearing, and then purely translational motion in a new direction via the second pushrod. =C2-I don't know what that is called, but you see it a lot on old warbirds, and you can change the direction of the pushrod to any angle you want with no concerns about durability.Steve RuseNorman , OK-- Sent from my Palm Pr=C4=93David Paule wrote:A bend will drastically reduce the compression strength of the push rod. =C2-The bend adds moment arm and then you have something called "beam-column bending" which tends to greatly reduce the compression strength of a simple column.=C2-For a particular case, you'd need to do some analysis. One of the better references is by Bruhn, and a good technical library will have a copy. Otherwise the ASM that I'd previously recommended will do fine, but it's a bit more difficult to use.=C2-But you can always make one like that and give it a try on the ground. If you can put your maximum strength on the stick without bending or collapsing the tube, it's probably okay. Hint - don't try that on the real airplane. Try it on a mockpit with test hardware, not flight hardware.=C2-David Paule=C2------ Original Message -----
Another thing to consider is the effect of repeated bending on that push rod at the bend. =C2-Eventually that rod will weaken from fatigue. =C2-I don't know enough to tell you how to calculate when it would fail from fatigue, but eventually it probably would. =C2-It might be after 100hrs or 100,000hrs, I have no idea. =C2-It will depend on the bend angle, stick forces, etc.One elegant way to deal with this broblem is to put a bearing where you need the bend and attach two pushrods to it, one on each side, so you have translational motion on the first pushrod, purely rotational motion around the bearing, and then purely translational motion in a new direction via the second pushrod. =C2-I don't know what that is called, but you see it a lot on old warbirds, and you can change the direction of the pushrod to any angle you want with no concerns about durability.Steve RuseNorman , OK-- Sent from my Palm Pr=C4=93David Paule wrote:A bend will drastically reduce the compression strength of the push rod. =C2-The bend adds moment arm and then you have something called "beam-column bending" which tends to greatly reduce the compression strength of a simple column.=C2-For a particular case, you'd need to do some analysis. One of the better references is by Bruhn, and a good technical library will have a copy. Otherwise the ASM that I'd previously recommended will do fine, but it's a bit more difficult to use.=C2-But you can always make one like that and give it a try on the ground. If you can put your maximum strength on the stick without bending or collapsing the tube, it's probably okay. Hint - don't try that on the real airplane. Try it on a mockpit with test hardware, not flight hardware.=C2-David Paule=C2------ Original Message -----
RE: Pietenpol-List: Bend in push pull tube
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Michael,Here are some pics of my idler arm. My seat bottom is framed per plans. Thepush/pull rod travels up and down at the idler arm, approximately =BE=94.Just a thought=85if you ran two stringers along the bottom of your fuse,beyond the seat bottom, you could easily pick up another 1=94 of clearance.Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done, Fuselage on gear(16 ribs down=85) _____
Michael,Here are some pics of my idler arm. My seat bottom is framed per plans. Thepush/pull rod travels up and down at the idler arm, approximately =BE=94.Just a thought=85if you ran two stringers along the bottom of your fuse,beyond the seat bottom, you could easily pick up another 1=94 of clearance.Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done, Fuselage on gear(16 ribs down=85) _____
Re: Pietenpol-List: Bend in push pull tube
Original Posted By: Michael Perez
Subject: Re: Pietenpol-List: Bend in push pull tubeBuilding my scout I had to route cables this way to stop any interference. My elevator cables do not rub, but had to use a double horn. string is to check alignment________________________________________________________________________________Date: Sat, 2 Jan 2010 18:45:59 -0800 (PST)
Subject: Re: Pietenpol-List: Bend in push pull tubeBuilding my scout I had to route cables this way to stop any interference. My elevator cables do not rub, but had to use a double horn. string is to check alignment________________________________________________________________________________Date: Sat, 2 Jan 2010 18:45:59 -0800 (PST)
Pietenpol-List: Bend in push pull tube
Original Posted By: douweblumberg(at)earthlink.net
Re: Pietenpol-List: gap sealing
Original Posted By:
Douwe, you must have used the wrong vinyl! I've used it on serveral planes and know others that use it and this is the first time I've heard of it being fragile. I use it in cold as well as hot weather. I wasn't awear there were different grades or thickness. I bought my vinyl from a sign maker. Very tough stuff. If you decide to try it again, you might check with the seller about the thickness.Gene----- Original Message -----
Douwe, you must have used the wrong vinyl! I've used it on serveral planes and know others that use it and this is the first time I've heard of it being fragile. I use it in cold as well as hot weather. I wasn't awear there were different grades or thickness. I bought my vinyl from a sign maker. Very tough stuff. If you decide to try it again, you might check with the seller about the thickness.Gene----- Original Message -----
Pietenpol-List: gap sealing
Original Posted By: Jim Markle